[Cornell Mniversity Library BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Henry W. Saqe 1891 N.O4Y36 23/3/95 ye Cornell ‘University ‘Library : : arV19069 i iit "oti, ane 1924 031 255 890 MANUAL OF BOTANY. By the same. In one volume, royal 8vo, pp. III7, price 21s. CLASS-BOOK OF BOTANY, Illustrated with 1800 Wood Engravings. Unitorm with above, price 7s. 6d. PALZONTOLOGICAL BOTANY. In foolscap 8vo, illustrated, price 3s. 6d. ELEMENTS OF BOTANY. In fcap. 8vo, second Edition, with Map, 3s. 6d. THE FLORA OF EDINBURGH. A MANUAL OF BOTANY BEING AN INTRODUCTION TO THE STUDY OF THE STRUCTURE, PHYSIOLOGY, AND . CLASSIFICATION OF PLANTS BY JOHN HUTTON BALFOUR, A.M., M.D. Epin., FBS, Sec. BSE, PLS, PROFESSOR OF MEDICINE AND BOTANY AND DEAN OF THE MEDICAL FACULTY IN THE UNIVERSITY OF EDINBURGH, HER MAJESTY’S BOTANIST FOR SCOTLAND, AND REGIUS KEEPER OF THE ROYAL BOTANIC GARDEN. FIFTH EDITION WITH UPWARDS OF NINE HUNDRED ILLUSTRATIONS EDINBURGH ADAM AND CHARLES BLACK 1875 ~ Printed by R. & R. CrarK, Edinburgh, ORIGINAL DEDICATION IN 1849. TO ROBERT KAYE GREVILLE, LL.D. AS A SMALL BUT SINCERE MARK OF REGARD FOR HIS EMINENCE AS A BOTANIST, OF GRATITUDE FOR HIS KIND BOTANICAL SERVICES, AND OF ESTEEM FOR HIS CHARACTER AS A CHRISTIAN FRIEND, THE FOLLOWING PAGES ARE DEDICATED BY J. H. BALFOUR. ' PREFACE. —p— In drawing up this Manual of Botany, the object has been to give a comprehensive, and, at the same time, a condensed view of all departments of the science, including the microscopical structure of plants and their morphology, the functions of their various organs, their classification and distribution over the globe, and their condition at various geological epochs. Care has been taken to notice the plants used for commercial and economical purposes, and particularly those having medicinal properties. The principles of adaptation and order which prevail in the vegetable kingdom have been promi- nently brought into view, with their bearings on symmetry and arrangement. The physiology of plants has been considered in connec- tion with the anatomical structure of their different organs, and the recent views in regard to the embryogenic process in flowering and flowerless plants have been brought under notice. In the department of classification, the system of De Candolle has been more or less completely followed, and the characters of the Natural Orders have been briefly given. Tt has been shown that the great object of classification is to arrange plants according to their affinities in all important particulars, and thus to trace, what may be considered to be, Vili PREFACE. the plan of the Almighty and all-wise Creator. At the same time, in all systems it is necessary to have artificial means to aid in the study of genera and species. Such means, like an index, must be easily applied so as to assist the beginner in his studies. It is only the Botanist, who has an extended knowledge of the vegetation of the globe, who has examined the effects produced on vegetation by climate and other cir- cumstances of existence, and who has studied aberrant forms in connection with natural orders, that can take a correct view of the alliances of plants. The divisions of geographical and paleontological Botany are still in an imperfect state, and are undergoing constant changes from the discoveries of naturalists in various parts of the world. All that has been attempted in this volume is to give a very general outline of these subjects, and to call the attention of the student to the points which still require elucidation. In the Appendix will be found a description of the microscope, of its use as an instrument of research in histological Botany, and of the mode of making vegetable preparations. There are also added directions as to the col- lecting of plants and the formation of a herbarium, with hints as to alpine travelling, and as to the examination of a country in a botanical point of view. A full glossary of the ordinary botanical terms is likewise given. The study of Botany is well fitted to call the observant faculties into active exercise. It teaches the student to mark the differences and resemblances between objects, and leads to habits of correct observation and diagnosis, In the present day there is a growing feeling of its importance in mental PREFACE. ix culture, and a tendency to include it as a subject of study in the curriculum of Arts, as well as in that of Medicine. It is now also taking a place in our school-books, and thus becom- ing part of the education of the young. It is a science fitted for all ages, for all ranks, and for all seasons. “In youth, when the affections are warm and the imagination vivid ; in more advanced life, when sober judgment assumes the reins ; in the sunshine of fortune and the obscurity of poverty, it can be equally enjoyed. The opening buds of spring; the warm luxuriant blossoms of summer ; the yellow bower of autumn ; and the leafless desolate groves of winter, equally afford a supply of mental amusement and gratification to the Botanist.” It is hoped that the present Manual may aid in the promotion of a science the study of which is so well cal- culated to contribute to the enjoyment and wellbeing of mankind. The examination of the plants which clothe the surface of the globe, of the lilies of the field, and of the meanest moss or lichen in our path, is well fitted to call forth exalted views of the eternal power and Godhead of Him who hath made all these for His own glory, and whose providential care extends to the clothing of the grass of the field, which to-day is, and to-morrow is cast into the oven. 27 InvERLEITH Row, EDINBURGH, April 1875. INTRODUCTORY REMARKS. —_—_4+>—_ It has too often been supposed that the principal object of Botany is to give names to the vegetable productions of the globe, and to arrange them in such a way that these names may be easily found out. This is a most erroneous view of the science, and one which was perhaps fostered by some of the advocates of the Linnean system. The number of species collected by a botanist is not considered now-a-days as a measure of his acquirements, and names and classifications are only the mechanism by means of which the true principles of the science are elicited. The views in regard to a natural system proposed by Ray and Jussieu did much to emancipate Botany from the trammels of artificial methods, and to place it in its proper rank as a science. Their labours have been ably carried out by De Candolle, Brown, End- licher, Lindley, Hooker, Arnott, Bentham, and others. The -relative importance of the different organs of plants, their structure, development, and metamorphoses, are now studied upon philosophical principles. The researches of Gaudichaud, Mirbel, and Trecul, as to the structure and formation of wood ; the observations of Schleiden, Schwann, and Mohl on cell-develop- ment; the investigations of Brown, Schleiden, Fritzsche, Amici, Hofmeister, Tulasne, Darwin, Strasburger, Pringsheim, Cohn, Her- mann Miiller, and others, into the functions of the pollen, the fertilisation of plants, both phanerogamous and. cryptogamous, the development of the ovule and spore, and the formation of the embryo ; the experiments of Schultz, Decaisne, and Thuret, on the movements observed in the cells, vessels, and spores of plants, and various other physiological inquiries, have promoted much our knowledge of the alliances and affinities of plants. Thus the labours of vegetable anatomists and physiologists all tend to give xi INTRODUCTORY REMARKS. correct views of the relation which plants bear to each other, of the laws which regulate their development, and of the great plan on which they were formed by the Creator. There is a tendency, however, to speak of the laws of nature as if they were in themselves executive, and this has led to erroneous views of the system of the universe. Some there are who attempt to shut out God from His works by this means. The Creator is regarded as looking at the development of His plan, and watching its progress, but not requiring to exercise constant and unwearied superintendence of the minutest event. Nay, even when He creates animals with certain instincts, and plants with certain functions, He is represented like an imperfect work- man taking a lesson from the operations of the beings which He has made, and which, by their own efforts of selection, or by their own struggles for existence, complete what the Creator had set on foot. A certain mechanism is set agoing in some unknown way, and it continues to work according to definite laws. But what are laws unless there is some one to carry them out? The great Author of these laws must be always working in them and by them, and upholding them in their integrity and efficiency. No doubt the Creator is a God of order and method, and the operations of His wisdom and power are displayed in what we call laws. The execution of these laws, however, is just as won- derful and miraculous as is a fiat of creation, and requires equally the exercise of Almighty power. The uniformity of nature de- pends on the wisdom that made these laws and adapted them to all the varying conditions of the universe. In the course of Providence, however, there are every now and then marked events which seem to be at variance with this uniformity, as when a deluge overwhelms mankind, or when a sudden convulsion destroys the cities of the plain. Such events show that all things do not continue as they were from the beginning of the creation. Those who look for a progressive development and a gradual and eternal advance towards perfection in the living beings which cover the earth, without further creative fiats or movements per saltwm, forget, in their speculations, that a time is coming when, as the Apostle says, “the earth and the works that are therein INTRODUCTORY REMARKS. xiii shall be burned up,” and then shall there be ushered in “a new earth,” wherein righteousness shall dwell. We cannot but honour the man, who, by his genius and talent, has been enabled to develop one of the great laws of nature, and who feels and ac- knowledges that he has been the humble instrument to lift the veil to a certain extent which conceals the workings of the Almighty; but we have no sympathy with that discoverer in science, who, puffed up with intellectual superiority, puts the laws which he has elucidated in the place of the Creator, whose per- sonality and ever-working omnipresence he ignores. In studying, therefore, the laws which are exhibited in the economy of living beings, let us never, in. the pride of science and philosophy, forget Him who not only created all things but upholds all things, and by whom all things consist. While we apply ourselves with the earnestness of zealous students to examine those wondrous works which are sought out of all that have pleasure therein, let us take everything in connection with that Word which is the sole record of Truth, and which, as coming from the God of nature, must be in perfect harmony with the laws of nature. The Botanist, in prosecuting his researches, takes an en- larged and comprehensive view of the vegetation with which the earth is clothed. He considers the varied aspects under which plants appear in the different quarters of the globe, from the Lichen on the Alpine summits or on the Coral reef, to the majestic Palms, the Bananas, and Baobabs of tropical climes— from the minute aquatics of our northern pools to the gigantic Victoria of the South American waters—from the parasitic fungus, only visible by the aid of the microscope, to the enormous parasite discovered by Raffles in the Indian Archipelago. It is interesting to trace the relation which all these plants bear to each other, and the mode in which they are adapted to different climates and situations. The lichens are propagated by spores or germs so minute as to appear like thin dust, and so easily carried by the wind that we can scarcely conceive any place which they cannot reach. They are the first occupants of the sterile rock and the coral-formed island—being fitted to derive xiv INTRODUCTORY REMARKS. the greater part of their nourishment from the atmosphere and the moisture suspended in it. By degrees they act on the rocks to which they are attached, and cause their disintegration. By their decay a portion of vegetable mould is formed, and in pro- gress of time a sufficient quantity of soil is produced to serve for the germination of the seeds of higher plants. In this way the coral island is, in the course of years, covered with a forest of coco-nut trees. ‘Thus it is that the most despised weeds lay the foundation for the denizens of the wood; and thus, in the pro- gress of time, the sterile rock presents all the varieties of meadow, thicket, and forest. The Creator has distributed His floral gifts over every part of the globe, from the poles to the equator. Every climate has its peculiar vegetation, and the surface of the earth may be divided into regions characterised by certain predominating tribes of plants. The same thing takes place on the lofty mountains of warm climates, which may be said to present an epitome of the latitudinal distribution of plants. Again, if we descend into the bowels of the earth, we find there traces of vegetation—a vegeta- tion, however, which flourished at distant epochs of the earth’s history, and the traces of which are seen in the coal, and in the fossil plants which are met with in different strata. By the labours of Brongniart, Goeppert, Schimper, and others, these fossil remains have been rendered available for the purposes of science. Many points have been determined relative to their structure, as well as in regard to the climate and soil in which they grew, and much aid has been afforded to the Geologist in his investigations, The bearings which Botany has on Zoology are seen when we consider the lowest tribe of plants, such as Diatomaces. These bear a striking resemblance to the lowest animals, and have been figured as such by Ehrenberg and others. The observations of Thwaites on Conjugation have confirmed the view of the vegetable nature of many of these bodies. There appear, however, to be many productions which occupy a sort of intermediate territory between the animal and vegetable kingdom, and for the time being the Botanist and Zoologist must consent to joint occupancy. The application of botanical science to Agriculture and Horti- INTRODUCTORY REMARKS. xV culture has of late attracted much attention, and the chemistry of plants has been carefully examined by Liebig, Miilder, and Johnston. The consideration of the phenomena connected with germination and the nutrition of plants has led to important conclusions as to sowing, draining, ploughing, the rotation of crops, and the use of manures. The relation which Botany bears to Medicine has often been misunderstood. The medical student is apt to suppose that all he is to acquire by his botanical pursuits is a knowledge of the names and orders of medicinal plants. The object of the connec- tion between scientific and mere professional studies is here lost sight of. It ought ever to be borne in mind by the medical man, that the use of the collateral sciences, as they are termed, is not only to give him a great amount of general information, which will be of value to him in his after career, but to train his mind to that kind of research which is essential to the student of medicine, and to impart to it a tone and a vigour which will be of the highest moment in all his future investigations. What can be more necessary for a medical man than the power of making accurate observations, and of forming correct distinctions and diagnoses? These are the qualities which are brought into constant exercise in the prosecution of the botanical investigations to which the student ought to turn his attention, as preliminary to the study of practical medicine. In the prosecution of his physiological researches, it is of the highest importance that the medical man should be conversant with the phenomena exhibited by plants. For no one can be reckoned a scientific physiologist who does not embrace within the range of his inquiries all classes of animated beings; and the more extended his views, the more certain and comprehensive will be his generalisations. To those who prosecute science for amusement, Botany pre- sents many points of interest and attraction. Though. relating to living and organised beings, the prosecution of it calls for no painful experiments nor forbidding dissections. It adds pleasure to every walk, affords an endless source of gratification, and it can be rendered available alike in the closet and in the field. The prosecution of it combines healthful and spirit-stirring recrea- xvi INTRODUCTORY REMARKS. tion with scientific study ; and its votaries are united by associations of no ordinary kind. He who has visited the Scottish Highlands with a botanical party, knows well the feelings of delight connected with such a ramble—feelings by no means of an evanescent nature, but lasting during life, and at once recalled by the sight of the specimens which were collected. These apparently insignificant remnants of vegetation recall many a tale of adventure, and are associated with the delightful recollection of many a friend. It is not indeed a matter of surprise that those who have lived and walked for weeks together in a Highland ramble, who have met in sunshine and in tempest, who have climbed together the misty summits, and have slept in the miserable shieling—should have such scenes indelibly impressed on their memory. There is, moreover, something peculiarly attractive in the collecting of alpine plants, Their comparative rarity, the localities in which they grow, and frequently their beautiful hues, conspire in shed- ding around them a halo of interest far exceeding that connected with lowland productions. The alpine Veronica displaying its lovely blue corolla on the verge of dissolving snows ; the Forget- me-not of the mountain summit, whose tints far excel those of its namesake of the brooks ; the Woodsia, with its tufted fronds, adorning the clefts of the rocks; the nival Gentian concealing its eye of blue in the ledges of the steep crags ; the alpine Astragalus enlivening the turf with its purple clusters ; the dwarf mountain Lychnis choosing the stony and dry knoll for the evolution of its pink petals ; the Sonchus, raising its stately stalk and azure heads in spots which try the enthusiasm of the adventurous collector ; the pale-flowered Oxytropis confining itself to a single British cliff ; the Azalea forming a carpet of the richest crimson ; the Saxifrages, with their white, yellow, and pink blossoms, clothing the sides of the streams; the Saussurea and Erigeron crowning the rocks with their purple and pink capitula; the pendent Cinquefoil blending its yellow flowers with the white of the alpine Cerastiums and the bright blue of the stony Veronica; the stemless Silene giving a pink and velvety covering to the decomposing granite ; the yellow Hieracia, whose varied transition forms have been such a fertile cause of dispute among Botanists; the slender and deli- INTRODUCTORY REMARKS. Xvii cate grasses, the chickweeds, the carices, and the rushes, which spring up on the moist alpine summits ; the graceful ferns, the tiny mosses, with their urn-like thece, the crustaceous dry lichens, with their spore-bearing apothecia ; all these add such a charm to Highland Botany, as to throw a comparative shade over the vegetation of the plains. Many are the important lessons which may be drawn from the study of plants when prosecuted in the.true spirit of Wisdom. The volume of Creation is then made the handmaid of the volume of Inspiration, and the more that each is studied, the more shall we find occasion to observe the harmony that subsists between them. It is only Science, falsely so-called, which is in any way opposed to Scripture. Never, in a’single instance, remarks Gaus- sen, do we find the Bible in opposition to the just ideas which Science has given us regarding the form of our globe, its magni- tude, its geology, and the productions which cover the surface. “The invisible things of God from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead.” The more minutely we examine the phenomena of the material world, and the more fully we compare the facts of Science with Revealed Truth, the more reason shall we have to exclaim, in adoring wonder, with the Psalmist of old, “O Lord! how manifold are thy works! in wisdom hast thou made them all; the earth.is full of thy riches.” TABLE OF CONTENTS. —_>—_ Page PREFACE. és 2 . 3 s : 5 s vii INTRODUCTORY REMARKS . 2 fs : ‘ ‘ xi PART I.—VEGETABLE ANATOMY, ORGANOGRAPHY, AND PHY- SIOLOGY . : . . . . ‘ . 1 CHAPTER I.—ELEMENTARY ORGANS, OR VEGETABLE TISSUES 1 SEcTIoN I.—CELLULAR TISSUE. : 3 3 3 3 1. Form and Arrangement of Cells . . 4 3 2. Contents of Cells ; : a 8 3. Development and Functions of Cells ¢ : : 13 Sxction II.—VascuLaR TIssuE : ; : : 16 1. Form and Arrangement of Vessels 7 ‘ : 16 2. Development and Functions of Vessels . i : 21 Tabular Arrangement of Vegetable tissues . < ‘ 23 CHAPTER JI.—COMPOUND ORGANS FORMED BY THE TISSUES 25 Srction I.—OrGaNs OF NUTRITION OR VEGETATION. ; 25 1. Structure, Arrangement, and RE Functions. , 25 General Integument s ‘ 3 25 Stomata : A . : i 28 Hairs . ‘ ‘ ‘ ? ‘ 30 Glands ‘ . ‘ 34 Functions of the Epidermis ; A j : 36 Root or Descending Axis . : ‘ , 37 Structure of Roots. ‘ : si i 37 Forms of Roots ‘ y e . 40 Functions of Roots . : ‘ 2 43 Stem or Ascending Axis . y r Z ; 44 Forms of Stems - ; : . . 44 Internal Structure of Stems. é : ‘ 49 Exogenous or Dicotyledonous Stem. . ‘ 49 Anomalies in its Structure 7 . ‘ 60 Endogenous or Monocotyledonous Stem P 3 64 Acrogenous or Acotyledonous Stem. 70 Formation of the different al of ee and their special Functions 75 Leaves and their Appendages : ‘ - : 79 Structure of Leaves . ; : ; , 79 XxX TABLE OF CONTENTS. Venation of Leaves Forms of Simple Leaves Forms of Compound Leaves Petiole or Leaf-Stalk . Stipules Anomalous Forms of Leaves and Petioles Structure and Form of Leaves in the Great Divisions of the Vegetable Kingdom Phyllotaxis, or the Teer of Leaves on the Axis Leaf-buds ‘ Vernation Aerial and Subterranean Leaf- buds ‘ a Anomalies and Transformations of Leaf-buds . Tendrils Special Functions of Leaves Section II.—GENERAL VIEW OF THE FUNCTIONS OF THE NUTRI- 1. 2. 3. 4. TIVE ORGANS Food of Plants, and Sources whence they derive their Nourishment é e ‘ “ Chemical Composition of Plants Organic Constituents and their Sources Inorganic Constituents and their Sources . Chemical Composition of Soils Application-of Manure ~ : Various kinds of Manure Epiphytic and Parasitic Plants A Absorption and Circulation of Fluids Respiration of Plants . Effects of Certain Gases on n Living Plants Products and Secretions of Plants . ‘ Section IIJ.—Orcans or REPRODUCTION rE Structure, Arrangement, and Functions Inflorescence or the emeneentent of the flowers on the axis Tabular View of Inflorescence or Anthotaxis . Bracts or Floral leaves x . The Flower and its Appendages Flower-bud, estivation External Floral ve or the Floral Envelopes Calyx Corolla. Nectaries and Anomalies of the Petals. fi Inner Floral ey or the Essential Ongens of if Repro: duction Stamens Pollen . Disk. Pistil, Carpels, and Placenta Ovule . Functions of the Floral Envelopes 5 ‘ : . Functions of the Stamens and Pistil; Fertilisation or Fecundation 121 124 124 124 126 128 134 136 136 141 142 155 159 161 171 171 172 188 189 191 193 195 195 200 209 211 212 228 234 235 251 258 264 TABLE OF CONTENTS, Fertilisation in Cryptogamous or Flowerless Plants Fertilisation in Phanerogamous or Flowering Plants - Embryogenic process in Gymnnepermine Flower- ing Plants . Embryogenic process in Angiospermous Flower- ing Plants 6. Fruit or the Pistil arrived at maturity : Fruits which are the produce of a single ‘flower ‘ Fruits which are the poe of several ae united . Tabular arrangement of Fruits é 7. Maturation of the Pericarp Ripening of Fruits Grafting 8. Seed or Fertilised Ovule arrived at Maturity Embryo é 9. Functions of. the Seed . ‘ 6 “ Germination . g Vitality of Seeds Transportation of Seeds Direction of Plumule and Radicle Proliferous Plants “ é Duration of the Life of Plants 10. General Observations on the Organs of Plants, and on the mode in which they are arranged Symmetry of Organs. 5 Teratology : Szction IV.—Some GENERAL PHENOMENA CONNECTED WITH ‘VEGETATION : . . Vegetable Irritability , i : . Temperature of Plants ‘ . . Luminosity of Plants . . Colours of Plants . Odours of Flowers . Diseases of Plants Aor Doe PART II.—SYSTEMATIC BOTANY, TAXONOMY, OR THE CLASS- IFICATION OF PLANTS. . CHAPTER I,—SYSTEMS OF CLASSIFICATION Nomenclature and Symbols Linnean System ‘ ‘ é Natural System : : si " System of Jussieu ‘ i 7 System of De Candolle System of Endlicher System of Lindley . ‘ Henslow’s Comparison of Systems 7 é Natural arrangement by Hooker ‘ xxi, Page 266 281 291 295 298 309 316 318 319 320 323 325 335 343 344 348 349 352 357 359 362 363 365 374 374 388 389 390 396 397 405 405 411 413 415 418 418 419 420 422 423 TABLE OF CONTENTS. Page CHAPTER IIL—CHARACTERS OF THE CLASSES AND NATURAL ORDERS . s : ‘ 5 423 Sus-Kinepom I.—PHANEROGAMOUS PLANTS . 425 Class I.—Dicotyledones or Exogenz : : 425 Sub-class 1.—Thalamiflore . 7 . 425 1. Ranunculacee . 426, 20. Tremandracer. 442) 39. Aceracee . 458 2. Dilleniacee. . 428] 21. Tamaricacee . 442] 40. Sapindacee . 458 8. Magnoliaceer . 428/ 22. Frankeniacer .°443| 41. Meliaceze . 459 4, Anonacee . . 429] 23. Elatinacen . . 448| 42. Cedrelacer. . 460 5. Menispermaceer 430| 24. Caryophyllacee 444] 43. Ampelidee. . 460 6. Berberidacer . 4806| 25. Portulacacee . 445] 44. Geraniacee. . 462 7. Nymphezacee . 431} 26. Malvacer . . 446] 45. Vivianacee . 463 8. Sarraceniacee . 482] 27. Sterculiacee . 448] 46. Linacee . . 463 9. Papaveracee . 433] 28. Byttneriacew . 449|/ 47. Balsaminacer . 464 10. Fumariacee . 434) 29. Tiliacee . 450} 48. Oxalidacee. . 464 11. Crucifere . . 434] 30. Dipterocarpacer 451] 49. Tropeolaceer . 465 12. Capparidacee . 437] 31. Chlenacee. . 451] 50. Pittosporacee . 465 13. Resedacee . . 438} 32. Ternstroemiacee 452) 51. Zygophyllacee. 466 14. Cistacez . 489] 33. Olacacee . . 453] 52. Rutacez . 467 15. Canellacee. . 4389] 34. Aurantiacee . 453] 53. Kanthoxylacee 468 16. Bixacez . . 489] 35. Hypericacee . 455] 54. Simarubacee . 468 17. Violacese . 440| 36. Guttifere . . 456] 55. Ochnacew . . 469 18. Droseracee. . 441] 37, Erythroxylacee 457| 56. Coriariacer . 470 19. Polygalacee . 4411 38. Malpighiacee . 457 Sub-class 2.—Calyciflore. Section 1.—Polypetele. . 470 57. Stackhousiacee 470 69. Rhizophoracee 488| 81. Turneraceer. . 498 58. Celastracee . 471] 70. Vochysiacee . 488] 82. Paronychiacer . 498 59. Staphyleacee . 472| 71. Combretacer . 488] 83. Crassulacer . 499 60. Rhamnacee . 472| 72. Melastomacee. 489| 84. Ficoidee - 500 61. Anacardiacee . 473] 73. Philadelphaceew 489| 85. Cactacex - 500 62. Burseracee. . 475| 74. Myrtacee . . 490] 86. Grossulariacere 502 63. Connaracee . 476| 75. Onagracen . . 492) 87. Saxifragacee . 502 64. Leguminose . 476| 76. Halorageaceer . 493} 88. Bruniacee. . 504 65.-Moringacee . 482| 77. Loasacee . 493} 89. Hamamelidacez 504 66. Rosacez . 483| 78. Cucurbitacee . 494] 90. Umbellifere . 505 67. Calycanthacer. 487| 79. Papayacee. . 496] 91. Araliacese . 509 68. Lythracee . . 487! 80. Passifloracee . 497| 92. Cornacer . 509 Sub-class 2.—Calyciflore. Section 2.—Gamopetale. 510 93. Caprifoliacee . 510) 97. Calyceracee . 515)101. Stylidiacer. . 523 94, Rubiaces . 511) 98. Composite . . 517/102. Campanulacer. 524 95. Valerianaceee . 514] 99. Brunoniacee . 522/108. Lobeliacew. . 525 96. Dipsacacee. . 515|100. Goodeniacer . 522/104. Vacciniacer . 525 Sub-class 8.—Corolliflore . . . 526 105. Ericacex . 526,112. Jasminacez . 531/119. Gentianacemr . 539 106. Epacridacee . 527/113. Columelliacew. 532/120. Bignoniacee . 540 107. Ebenacee . . 528)114. Oleacer. - 582/121. Gesneracer . 541 108. Styracacee. . 529/115. Salvadoracee . 534]122, Polemoniacee . 541 109. Aquifoliacee . 529/116, Asclepiadacer. 534 | 123. Hydrophyllaces 542 110. Sapotacee . . 530)117. Apocynacer . 586)124. Convolvulacer. 542 111. Myrsinacee . 531|118, Loganiaceer . 537/125. Cordiacer . . 545 126. 127. 128. 129. 137. 138. 139, 140. 141, 142, 148. 144. 145. 146. 147. 148. 149, 150. 151. 152. 183. 185. 186. 187. 188. 197. 198, 199. 200. 209. 210. 213. 215. 216. 221.° Page Boraginacer . 545 Solanacee . . 547 Orobanchacee . 550 Scrophulariaceee 551 TABLE OF CONTENTS. xxiii Page Page 130. Labiate . . 5521134. Primulacee . 557 131. Verbenacee . 555|135. Plumbaginacer 559 132. Acanthacee . 556|186. Plantaginacee. 559 183. Lentibulariacee 557 Sub-class 4.—Monochlamydee. Section A.— Angiospermae . 560 Nyctaginacee . 560 Amaranthacee 562 Chenopodiaceee 562 Phytolaccaceer 563 Polygonacee . 563 Begoniaceer . 566 Lauracee . . 566 Myristicaceee . 569 Proteacee . . 570 Eleagnaces . 570 Peneacee . . 571 Thymeleacee . 571 Aquilariacez . 572 Chailletiacese . 572 Samydacee . 573 153. Santalacee. . 574/168. Podostemacee. 588 154. Loranthacee . 574| 169. Stilaginacer . 588 155. Aristolochiacee 575}170. Monimiacee . 588 156. Balanophoracee 577 | 171. Atherospermacee 589 157. Cytinacee . . 5771172. Lacistemacee . 589 158. Rafilesiacee . 577|173. Chloranthacee 590 159. Nepenthacese . 578|)174. Saururacee . 590 160. Datiscacee. . 578|175. Piperacee . . 590 161. Empetracee . 5791176. Salicacew . . 591 162. Euphorbiacee, 579|177. Myricacee . . 592 163. Urticacee . . 583|178, Casuarinacee . 593 164. Cannabinacer . 584/179. Betulacer . . 593 165, Ulmacee . . 585|180. Platanacee. . 593 166. Moracee . 586|181. Corylacer . . 594 167. Ceratophyllacex 588 1182. Juglandacee . 595 Homaliacer . 573 Section B.—Gymnosperme . : Z 529 Conifers 596 | 184. pesos . ; 600 Class II.—Monocotyledones or Endogenze ‘ ‘ : 601 Sub-class 1.Petaloideze é ‘ i 601 a.—Epigyne . - ‘ : : é 2 601 Hydrocharidacese601 | 189. Musacew . . 607 | 193. Dioscoreacer. 610 Orchidacee . 602| 190. Iridacee . . 608| 194. Amaryllidacee 611 Zingiberaceee . 605 Marantacee . 606 6.—Hypogyne Liliacee . . 613 Melanthacee . 616 191. Burmanniacese . 610 | 195. Hypoxidacee 612 192. Hemodoracee . 610 | 196. Bromeliacee . 612 - 7 . r ‘ 613 201. Gilliesiacee . 618| 205. Palme . 619 202. Pontederiacee . 618 | 206. Commelynacee 622 Smilacew . . 617 | 203. Xyridacer . . 618 | 207. Alismacee . 623 Trilliaceer . . 617 | 204. Juncacen . . 619 | 208. Butomacer . 623 c.—Incomplete ee , - : : 624 Pandanacez 624; | 211. Naiadacee . s . 626 Aracex 625 | 212. Restiacee . ‘ . 627 / Sohne 2.—Glumiferee : 4 ‘i 627 Cyperacese . 627 | 214, Graminez . . ' 628 Sus-Kinepom II.—Cryrrocamous PLANTS 2 z a . 635 Class ILI.—Acotyledons 7 ‘ : A ; 3 635 Sub-class 1.—Acrogene ‘ : 5 3 635 Equisetacess . 636 Filices . . 637 217. Marsileacee . 640{ 219. Musci. 641 218. Lycopodiaceee 640 | 220. Hepatice . 643 Sub-class 2.—Thallogene . ; : 7 644 Lichenes . . 644 | Additional Remarks 292, Fungi . . . 647 | 223, Characee . 651 224, Algo . . . . 652 on Fertilisation of Graminese 3 5 656 Xxiv TABLE OF CONTENTS. PART IIIL—GEOGRAPHICAL BOTANY, OR THE DISTRIBUTION OF PLANTS OVER THE GLOBE. I,—EPIRRHEOLOGY, OR THE INFLUENCE OF VARIOUS EXTERNAL AGENTS ON PLANTS < ‘ : ‘ 7 1. Effects of Temperature 2. Effects of Moisture 38. Effects of Soil, Light, and other Agents . II.—DIssEMINATION OF PLANTS 1. Agents employed in their Dissemination 2. General and Endemic Distribution of Plants 3. Conjectures as to the mode in which the Earth was origin- ally clothed with Plants * 4, Distribution of Plants considered Physiognomically and Statistically . Physiognomy of Vegetation - 675 | Statistics of Vegetation 5. Phyto-geographical Division of the Globe . Latitudinal Range of Vegetation 678 | Altitudinal Range of Vegetation Schouw’s Phyto-geographic Re- Zones of Marine Vegetation gions . . 679 | Distribution of Plants in Britain Meyen’s Phyto-geographical, Zones 692 | Acclimatising of Plants . PART IV.—FOSSIL BOTANY Character and arrangement of Fossil Fossiliferous Hed Plants. : s é 719 | Fossil Plants of different Strata 1. Flora of the Primary or Paleozoic Period . 4 - Reign of Acrogens : : 2. Flora of the Secondary or Mesozoic Period Reign of Gymnosperms ‘ ‘ 38. Flora of the Tertiary or Cainozoic Period : Reign of Angiosperms < = . APPENDIX . ‘ z I.—On THE Use OF THE AsoRRbORE IN Bedusenaa RESEARCHES II,—Ow CoLLECTING AND EXAMINING PLANTS, AND ON THE Forma- TION OF A HERBARIUM j ; GLOSSARY . : : : : . i : ‘ABBREVIATION S AND SYMBOLS . é r “; zB INDEX ‘ a . Page 657 657 658 662 662 668 668 670 671 675 677 678 695 699 702 716 718 723 724 728 728 745 745 750 750 761 761 795 809 830 831 PART I. VEGETABLE ANATOMY, ORGANOGRAPHY, AND PHYSIOLOGY, —~+—_ Borany is that branch of Biological science which comprehends the knowledge of all that relates to the Vegetable kingdom. It embraces a consideration of the external configuration of plants, their structure, the functions which they perform, the relations which they bear to each other, and the uses to which they are subservient. It takes a comprehensive view of the vegetation with which the earth is clothed at the present day, and of that which covered it at former epochs. It has been’ divided into the following departments :—1. Structural Botany, or Organography, having reference to the anatomical structure and the forms of the various parts of plants, including vegetable histology, or the microscopical examination of tissues ; and morpho- logy, or the transformations which the organs undergo. 2. Physiological Botany, the consideration of the functions performed by the living plant, or the phenomena of life as exhibited by its various organs during the processes of development, growth, and multiplication. 3. Systematical, or Taxological Botany, the arrangement and classifica- tion of plants, 4. Geographical Botany, the distribution of plants in space, 5. Fossil, or Paleontological Botany, the distribution of plants in time, with a description of the form and-structure of the plants found in a fossil state in the various geological formations. CHAPTER I. ELEMENTARY ORGANS, OR VEGETABLE TISSUES. In their earliest and simplest state plants consist of minute vesicles, each of them bounded by a transparent membrane, which is composed of a substance called Cellulose, This.substance is of general occurrence, and constitutes the basis of vegetable tissues. It is composed of carbon, hydrogen, and oxygen, and the chemical formula representing B 2 ELEMENTARY ORGANS. it is OC, H,, 0,.* It was long considered as essentially a vegetable product, not found in animal structures ; but it has now been de- tected in the tissues of the ascidia, and other molluscous animals. It is a white substance, insoluble in water, alcohol, or ether, but soluble in an ammoniacal solution of cupric oxide. It is allied to starch, into which it is convertible by the action of heat, the addition of sulphuric acid, or caustic potash. It becomes yellow on the addition of iodine, and when acted upon by iodine and sulphuric acid, a blue colour, like that of iodide of starch, is produced. The acid appears to convert the cellulose into starch. When cellulose is acted on by a mixture of equal volumes of strong sulphuric and nitric acid it forms gun-cotton (pyroxylin), (vie, fire, and EvAov, wood), and this when dissolved in a mixture of ether and alcohol yields a solution called collodion. The membrane formed by cellulose is permeable by fluids, and becomes altered in the progress of growth, so as to acquire various degrees of consistence. A modification of cellulose occurs in the form of woody matter or lignin. The hard cells in the stone of the peach, in the shells of other fruits, and in the coats of seeds, consist of cellulose, with deposits of lignin. In the advanced stages of growth, plants consist of two kinds of tissue, Cellular and Vascular, which, under various modifications, constitute their Elementary organs ; and these, by their union, form the Compound organs, by which the different functions of plants are carried on. The elementary organs are vesicles and tubes, which vary in form and size, and, when united in different ways, constitute the tissues. Vesicles or cells may be defined as closed sacs, composed of 9 solid membrane, containing fluid or semifiuid matter, and having a diameter nearly equal in every direction (fig. 1) ; Fig. 1. while tubes or vessels are similar sacs with the longitudinal much exceeding the transverse diameter (figs. 3, 4). Cellular tissue is formed by a combination of these cells or vesicles ; a similar union of vessels constitutes vascular tissue. Fig. 1. Vesicles or small cells, each of them enclosed by a membrane of cellulose. “+ These symbols indicate the equivalents of Carbon (C), Hydrogen (H), and Oxygen (0), which enter into the composition of cellulose. For the meaning of these and other chemical symbols, see Chap, II. Sect. I. Div. 2, on the Food of Plants. CELLULAR TISSUE. 3 Section: I.—CELLULAR Tissue. 1.—Form and Arrangement of Cells. CELLULAR TissvE is formed by the union of minute vesicles or bladders, called ceils, cellules, or utricles, This tissue is often called Parenchyma (vugd, through, and ¢yxvc, an infusion). The terms Parenchymatous, Areolar, Utricular, and Vesicular, when applied to vegetable tissues, may be considered as synony- mous, The individual cells of which this tissue is com- posed, when allowed to develop equally in all directions, are usually of a more or less rounded form (figs. 5, 6, 7) ; but during the progress of development they frequently 4 become more elongated in one direction than in another | (fig. 2), and often assume angular or polyhedral forms (fig. 8 Figs. <3 Neal “ "9: 18. 4, Fig. 5. Fig. 6. Fig. 7. Fig. 8. The following names have been applied by Morren and other authors to the tissue made up of variously-formed cells :—1. Paren- chyma, a general name for cellular tissue, but often applied to that consisting of dodecahedral cells (figs. 8, 12, 13), which, when cut in any direction, exhibit a hexagonal form (figs. 14, 15), and hence the .tissue is sometimes called hexagonenchyma (#&dywvos, six-angled) ; it is . : NUN Fig. 9. Fig. 10. Fig. 11. Fig. 12. ‘ Fig. 13. seen in the pith of the Elder, and in young palm stems, 2. Spheren- chyma (spaiga, a sphere), spheroidal cells (fig. 5). 3. Merenchyma e Fig.2, Fusiform or spindle-shaped cell. _— Figs. 3, 4. Tubes or vessels. Figs. 5, 6, 7 8, Cells, or utricles, separate and combined. Figs. 9, 10, 11, 12, 13. Figures representing the forms of cells. 4 FORM AND ARRANGEMENT OF CELLS. (ungia, to revolve), ellipsoidal cells (fig. 6). 4. Ovenchyma (adv, an egg), oval cells. Round, elliptical, and oval cells, are common in herbaceous plants. 5. Conenchyma (xéivos, a cone), conical cells, as hairs. 6, Columnar cellular tissue, divided into Cylindrenchyma (xtAwégos, a cylinder), cylindrical cells (fig. 17 a), as in Chara, and Prismenchyma (xgiowa, a prism), prismatical cells, seen in the bark of some plants (fig. 10). When flattened, prismatical- cells form the muriform (murus, a wall, like bricks of a building) tissue of the medullary rays of woody stems, and when much shortened they assume a tabular form, constituting Pinakenchyma (iva, a table), tabular cells (fig. 11), or square cells (fig. 9). 7. Prosenchyma (sgés, indicating addition), or Atractenchyma (dreuxros, a spindle), fusi- form or spindle-shaped cells, seen in woody structures (fig. 2). 8. Colpenchyma (xéAros, a sinus or fold), sinuous or waved cells, as in the cuticle of leaves. 9. Cladenchyma (xAd6oc, a branch), branched cells, as in some hairs. 10, Actinenchyma (duric, a ray), stellate or radiat- ing cells, as in Juncus and Musa (fig. 16). 11. Dedalenchyma (daidadros, entangled), entangled cells, as in some Fungi. 3 & Fig. 14, Fig. 15. Fig. 16. * The size of cells varies not less than their figure in different plants, and in different parts of the same plant. They are frequently seen from stu, stv, to rvs of an inch in diameter. In cork, which is cellular, there are about a thousand in the length of an inch. In’ the pith of Elder cells rio of an inch in diameter are seen, In many succulent vegetables, and in the pith of some aquatic plants, large cells ranging from ¢o to vo of an inch in diameter occur ; while the cells in spores of Fungi have been computed at scx of an inch in diameter. In a cubic inch of the leaf of a carnation, there are said to be upwards of three millions of cells. , Each cell has originally a separate membranous wall, but in the progress of growth the walls of contiguous cells may become united. When cells are united by their extremities (fig. 17), their, partitions are occasionally absorbed so as to form continuous tubes. When cells are united in a rectilinear manner, those in contiguous rows are Figs. 14, 15. Hexagonal cells, cut longitudinally and transversely. Fig. 16. Branching, stellate, or radiating cells of Vicia Faba, the common bean. 11, Intercellular lacune, or air-spaces between the cells. FORM AND ARRANGEMENT OF CELLS. 5 either directly opposite to each other, that is, are placed at the same height (fig. 18), or are alternate, from being placed at different heights (fig. 19) ; cells sometimes communicate with each other later- ally (fig. 20 aa). Isolated cells, as spores of sea-weeds, occasionally have free filaments, or cilia (ciliwm, an eyelash), developed on their surface, Fig. 17. Fig. 18. Fig. 19. The simplest kinds of plants, as mushrooms and sea-weeds, are composed entirely of cellular tissue, and are called Cellulares, The pulpy and succulent parts of all plants contain much cellular tissue, and the object of horticultural operations is to increase the quantity of this tissue in ordinary fruits and vegetables. The pith of trees, and plants during their early development are cellular; so also are cotton and rice-paper. The cell may be considered as the ultimate struc- tural element of all organisms. In the simplest vegetable forms, as in unicellular alge, it is adequate to all the purposes of plant life. Vital operations are carried on in all plants by means of cells, the constitu- tion and functions of which vary according to the nature of the plants and the position in the scale of organisation which they occupy. In the higher classes of plants, certain cells are concerned in the secre- tion:of organisable products, which are elaborated by others into new tissues. The life of the higher species of plants results from the regular action of cells, which are of unequal value as regards the for- mation of new organs and new products. In cells there are observed the absorption and movements of fluids, the elaboration of these by exposure to air and light, and the formation of new cells. Schacht remarks that a plant is composed of one or more cells, and that it is only. in the lowest species that the cells are of the same value ; in other words, are of the same chemical and physical nature, and of the same physiological importance. Even amongst the mushroom and sea- weed orders, it is only the lowest plants which have cells concerned alike in the processes of vegetation and reproduction. The higher plants of these orders are composed of parts having different values. Figs. 17, 18, 19. Cells united together by their extremities, Fig. 20. Elongated thickened cells from the root of the Date Palm. aa, Canals of communication. 6 FORM AND ARRANGEMENT OF CELLS. In general, no visible openings can be detected in cells, although fluids pass readily into and out of them. Harting and Miilder, how- ever, state, that they have observed perforations in the cells of Hoya carnosa, Asclepias syriaca, Cycas revoluta, Virginian spiderwort, and Traveller’s joy. In one cell (from a Euphorbia), having a transverse diameter of 0:03777 millimetres,* they counted 45 minute holes. In some mosses, also, openings have been found in the cells, as in Sphagnum and Leucobryum glaucum. Porous on Prrrep Cetzs are those in which the membrane is thickened at certain parts, leaving thin rounded spots intervening, which, when viewed by transmitted light, appear like perforations or pores (figs. 21, 28). The unequal deposit of the internal en- crusting cellulose or woody matter, is the cause of this condition. The pores of contiguous cells usually corre- spond as regards position, and sometimes the membrane becomes absorbed between them, so as to allow a direct communication by means of lateral canals, as is seen in 3 the cells from the root of the Date (fig. 20, aa). When ss oe porous cells are united end to end, so as to form tubes, ; " the tissue is denominated articulated Bothrenchyma or Taphrenchyma (R60gog and régeos, a pit), on account of their bead- like appearance, and the pits or depressions in their thickened walls (fig. 22). Pitted cells are seen in Elder pith. Frerous ok SPrraL CELLS are those in which there is a spiral elastic fibre coiled up in the inside of the membrane (fig. 23). When united they form jibro-cellular tissue, or Inenchyma (ives, fibres). These Fig. 24, Fig. 25. Fig. 26. cells generally consist of membrane and fibre combined, but the former appears to be sometimes absorbed wholly or partially during the progress of growth. The membrane, in some instances, is easily dissolved by water, and then the elastic close convolutions of the fibre spring out with considerable force, as in the outer covering of the seeds of Collomia linearis, and in the pericarp of Salvia. Spiral cells Fig. 21. Porous cell, from the Elder (Sambucus nigra). Fig. 22, Articulated Both- renchyma, or Taphrenchyma, from Mistleto, having a moniliform appearance. Figs. 23, 24,25. Spiral, annular, and reticulated cells, from Mistleto (Viscum album). Fig. 26. Scalariform and dotted cell, from Elder (Sambucus nigra). * A millimetre is about 1-25th of an English inch. FORM AND ARRANGEMENT OF CELLS. 7 abound in many of the Orchidaceous plants, as Oncidium and Pleurothallis ruscifolia, also in the garden Balsam, in the leaf of the moss called Sphagnum, and in the Cactus tribe. They are also found in the inner covering of anthers, in the spore-cases of many of the lower tribes of plants, and in the coats of the seeds'of Acanthodium spica- tum, Sphenogyne speciosa, Calempelis scaber, and Cobza. The spiral filaments sometimes exhibit peculiar movements when placed in water. The fibre in these cells varies from about seov to rotvs of an inch in diameter ; it is solid, and presents either a circular, an elliptic, or a quadrangular section. The coils of the fibre sometimes separate from each other, and become broken up and united in various ways, so as to appear in the form of rings, bars, or dots, thus giving rise to annular (fig. 24), reticulated (fig. 25), scalariform and dotted cells (fig. 26), which constitute the spurious or imperfect Inenchyma of authors. Annular cells are met with in Opuntia, and in the endothe- cium of Cardamine pratensis ; reticulated cells, caused by fibres forming a sort of mesh or network, are seen in the wing of the seed of Swietenia, the pericarp of Picridium tingitanum, the leaf of Sanseviera guineensis, and the pith of Rubus odoratus and Erythrina Corallodendron, as well as in the endothecium of the sea-pink and the butterwort. In certain parts of plants cells are placed closely together, and touch each other by flat surfaces, filling up space completely, and leaving no intervals; they then form the perfect Parenchyma of Schleiden (figs. 8, 27). In lax tissues, however, the. cells retain a rounded shape, and then touch each other at certain points only, leaving intervals of various sizes and shapes, and forming the ¢tniper- fect Parenchyma of Schleiden (figs. 7, 28). These intervals, when of moderate size and continuous, are called intercellular passages or canals ; when large, irregular, and circumscribed, intercellular spaces, or Lacune (fig. 16, 72). Fig. 27. Fig. 28. A difference of opinion prevails as to the mode in which cells are united together. Some maintain that the cell-walls in the young Fig. 27. Cellular tissue, from pith of Elder. Fig. 28. Porous merenchyma, from Houseleek (Sempervivum tectorwm). u, Intercellular canal. 8 CONTENTS OF CELLS. state unite together directly, and become agglutinated, more or less, according to their places of contact. Others, as Mohl and Henfrey, hold that there is an intercellular matter which acts as a sort of cement, or Collenchyma (xéAAc, glutinous matter). In sea-weeds, the cells, of which the entire plant is composed, are placed at a distance from each other (fig. 29, aa), and the intervals are filled up by this intercellular substance (fig. 29, b), which thus forms a large part of their bulk. In the higher classes of plants, when the cells touch each other, the layer of intercellular matter must be very thin, except in the intercellular canals or spaces. Mirbel looks upon it as the Fig. 29, Fig. 30. remains of the mucilaginous fluid in which the cells were originally developed, and which has become thickened to a greater or less de- gree, as in the root of the Date (fig. 30), where aaa indicate the cells, and 6 6 b the interposed substance. 2.—Contents of Cells. The external membrane of cells is composed of the unazotised substance called Cellulose, and in their interior a mucilaginous matter is contained, which undergoes changes in the progress of growth. This mucilaginous matter is the Protoplasm (aearog, first, and rAdoue, formative matter) of Mohl, the Cytoblastema (xiros, a cell, and Br.déornwx, growth) of some authors. It is at first homogeneous, but ultimately assumes a granular form. The appearance of granules may be regarded as the earliest evidence of the formative process. Protoplasm contains nitrogen in its composition, or is azotised, and it assumes a brownish colour when acted upon by iodine. It forms a mucilaginous layer on the inner surface of the cell-wall, and thus gives rise to the internal utricle of Harting and Milder, the primordial utricle of Mirbel. This inner membrane is visible in the young state of the cell, and under the action of tincture of iodine may be made to contract and separate from the outer cell-wall. It may also be rendered distinct by the action of strong hydrochloric acid, and by diluted sulphuric acid. When the process of lignification or thickening has advanced, this utricle dis- appears, in consequence of becoming incorporated with the cell-wall. Fig. 29. Cellular tissue of Sea-weed (Himanthalia lorea). aa, Cells. 6, Intercellular matter. Fig. 30. Central portion of young root of Date. aaa, Thickened cells. bbb, ntercellular substance of Mirbel. CONTENTS OF CELLS. 9 When small portions of vegetable tissue are soaked in Beale’s Car- mine solution, only those cells containing protoplasm appear stained. The nuclei and granules in the protoplasm seem alone to be affected. The depth of colouring depends on the number of granules in the protoplasm and the size of the nuclei. In certain cells the membranous wall consists throughout life of a thin layer of cellulose, while in others it becomes thickened by the deposition of matter on its inner side. These secondary deposits are sometimes of a gelatinous consistence ; at other times they are hard, In the latter case, the matter is looked upon as a modification of cellulose, and has received the name of kignin (lignum, wood), or sclerogen (oxAngds, hard, and yevdew, to generate). On making sec- tions of such cells, in a transverse (fig. 31) or longitudinal direction (fig. 32), the successive layers may be seen either continuous all round, or leaving parts of the membrane uncovered. Cells of this kind are well seen under the microscope in thin sections of the hard shell of the Coco-nut, and Attalea funifera, and of the hard seed of the Ivory Palm. In all cell deposits there is a tendency to a spiral arrangement. When the deposition is uniform over the whole surface, this arrangement may not’ be detected; but when interruptions take place, then the continued coil becomes evident. In spiral cells the fibre seems to be formed before the full development of the cell, the coils of the fibre being at first in contact, and afterwards separated, whereas the second- ary thickening layers are deposited after the cell is fully formed. Ac- cording to the observations of Barry, Agardh, and others, the filamentous origin of fibrous structures is recognisable in the earliest stage of cell growth, and the interweaving of these filaments constitutes the cell-walls. Each cell is found to contain at some period of its existence a small body called a nucleus (fig. 33, x), in which there are often one or two, rarely more, minute spots called nucleoli, The nucleus is of a round or oval shape, granular and dark, or homogeneous and trans- parent, bearing some resemblance to a smaller in- ternal cell. Nucleoli are not always present. They are either vesicles and granules contained in the nucleus, or minute cavities in its substance. The latter view is supported by Barry, who holds that a peculiar substance called hyaline (Uados, glass) is developed there, which, according to him, is the origin of the nucleus. The nucleus is situated at different parts of the cell. It is either free in its cavity, or connected with its walls by mucilaginous Fig. 31. Fig. 33. Fig. 31. Transverse section of cells from pulp of Pear. Fig. 32. Longitudinal section ofthe same. Fig. 33. Nucleated cells from the Beet. 10 CONTENTS OF CELLS. threads, or embedded in the substance of the membrane. The addi- tion of acetic acid often renders the nucleus distinct. STARCHY MATTER is found in cells, which constitute the tissue called by Morren, Perenchyma (area, a sac). Starch exists in the form of granules, which are minute cells (perhaps nuclei, as Miilder states), in which nutritious matter is stored up. This matter may be deposited in such a way as to give the appearance of strie surrounding a point or hilum, which is considered as an opening into the cell. Allman says the starch granule consists of a series of lamella, in the form of closed hollow shells, included one within another, the most internal inclosing a minute cavity filled with amorphous amylum. The concentric striz visible on the granule indicate the surface of contact of these lamelle, and the so-called nucleus of Fritsche corre- sponds to the central cavity. The external and internal lamelle differ in consistency, and in other conditions of integration. The lamelle are deposited centripetally. The starch granule differs from a true vege- table cell in the absence of a proper nucleus, and in presenting no chemical difference between the membrane and the contents. The grains of starch are well seen in the cells of the potato (fig. 34). In Fig. 34. Fig. 35. Fig. 36. wheat (fig. 35), and in maize (fig. 36), the form of the granules, and the successive layers of deposit, are also seen. The grains in the stem of Nuphar luteum show the centripetal formation, that is, the increase by layers deposited within each other. The addition of iodine causes the grains of starch to assume a blue colour, and marks the difference between them and the walls of the cell containing them. Schleiden affirms that starch is the most widely diffused substance in the vegetable kingdom ; its presence may be regarded as in a measure indicating the age of the cell, With its formation in many cells, we have a limitation of vital activity, by which the organism is brought into such a condition that the power of germination may be preserved for a very long period. Crystats are found in the interior of cells. They probably owe their origin to the union between the acids produced or taken up by plants, as oxalic, phosphoric, malic and carbonic, and the alkaline matter, as lime and potash, absorbed from the soil and circulating in the sap. The crystals usually lie loose in the cells (figs. 37, 38) ; but they are sometimes found in a distinct tissue called a cystolith (xvoris, bladder, and Asoc, a stone), suspended from the wall of a Fig. 34. Cell of Potato, containing striated starch grains. Fig. 35. Grains of starch of Wheat. Fig. 36. Grains of starch of Maize. CONTENTS OF CELLS. 11 large cell (fig. $39)—filling what some have supposed to be the base of an undeveloped hair. The crystals are of different sizes and forms. Occasionally, a single large crystal nearly fills a cell, as in the outer scales of the onion, but in general there are numerous erystals united to- gether. Sometimes the crystals radiate from a common point (figs. 40, £1), and form a conglomerate mass ; at other times they lie parallel, and have the appearance of bundles of fine needles (figs. 37, 38). To the latter, the name of Raphides (2a2/:, a needle), or acicular crystals (acus, a needle), was originally given. It has been said ; that these crystals exist also in the intercellular spaces; 9 PS *- but this seems to depend on the mode in which the section of the plant is made, for when raphidian cells (fig. 42, r r r r) are situated close to a lacuna, the crystals may easily be pushed into it accidentally by the knife. Raphides consist principally of phosphate and oxalate of lime. They abound in some plants, especially Cacti, and they are common in Squill, and in the officinal Turkey Rhubarb, the latter of which owes its grittiness to their presence. One hundred grains of rhubarb root Fig. 41. contain about 30 or 40 grains of oxalate of lime crystals. Acicular crystals may be easily seen by making a section of any Liliaceous plant. as the hyacinth, and spreading the thick mucilaginous matter of the cells on the field of the microscope. Radiating raphides are seen in the sepals of Geranium robertianum and lucidum ; the crystals, consisting of oxalate of lime, fill the whole of the cells in the middle of the sepal, their size varying from zv'sv to rs'ow of an inch. Quekett found them in all the species of Pelargonium and Monsonia that he examined, and he thinks that they are as general as the beautiful markings in the cuticle of the petals of these plants. Clustered crystals have been detected in Malvaceous plants, under the cuticle of the Fig. 37. Cellular tissue of Arum maculatum. ¢, Cells containing chlorophyll. rr, Raphidian cells. Fig. 38. Cells of Arum maculatum. Clusters of raphides in a large oval cell surrounded by smaller cells. Fig. 39. Cellular tissue from leaf of Ficus elastica c, A large cell. 7, Cystolith, an agglomeration of erystals (spheraphides) suspended in a sac by atube,# «, Utricles filled with grains of chlorophylL__ Fig. 40. Cells of Beet with conglomerate radiating crystals, a. >, Separate erysials of different forms. Fig. 41. Con- glomerate crystals of oxalate of lime from Rhubarb. 12 CONTENTS OF CELLS. Marvel of Peru, and in the sepals of the strawberry ; numerous _ acicular crystals have been observed in Fuchsias, and solitary cubical crystals in the superficial cells of the sepals of Prunella vulgaris and Dianthus Caryophyllus. In the outer covering of the seed of Ulmus campestris, the sinuous boundaries of the | compressed cells are traced out completely by minute rectangular crystals adhering to each other. Unger detected oxalate of lime crystals in Ficus indica and Calathea zebrina. Accord- ing to Dr. Gulliver the presence or absence of raphides may be used for distinguishing certain natural orders. He says that Balsaminacez, Onagracez, and Galiacez, may be specially called Raphis-bearing orders. In the epidermal cells of many Urticacez concretions of carbonate of lime (cystoliths) are found.* CHLOROPHYLL (yAweds, green, and @uAAov, a leaf), or the green colouring matter of plants, floats in the fluid of cells, accompanied by starch grains. It differs from starch in being confined to the super- ficial parenchyma, and in being principally associated with the phe- nomena of active vegetable life. It has a granular form (fig. 39, w ; 42, c), is soluble in alcohol, and is developed under the agency of light. It is well seen in leaves, Under the influence of darkness it under- goes changes which are seen in the phenomenon of blanching or etiola- tion. Its granules are usually separate, but sometimes they unite in masses (fig. 37, c). Stokes says that the chlorophyll of land plants consists of four substances, two green and two yellow, all possessing highly distinctive optical properties. The green substances yield solutions exhibiting a strong red phosphorescence; the yéllow sub- stances do not. These substances are soluble in the same solvents. Green sea-weeds agree with land plants. Red sea-weeds in addition to chlorophyll contain a red colouring matter of an albuminoid nature. Chlorophyll is important in a physiological point of view. It is developed under the influence of light, and the granules exhibit marked movements, as have been observed in the leaves of some mosses. Chlorophyll gives a black band in the red of the spectrum. Green vesicles or granules allied to chlorophyll are found in some of the lower animals, as Hydra viridis. Other kinds of colouring matter are also produced during vegetation, and occur in the form of fluids or of granules in the interior of cells, \ Oris and RESINOUS MATTER are found in the interior of cells, as well as in intercellular spaces. The cavities containing them are denomi- nated cysts, reservoirs of oil, and receptacles of secretions, They are easily Fig. 42. Cellular tissue of Colocasia odora. cc, Cells with grains of chlorophyll. rrr, Raphidian cells projecting into a lacuna or intercellular space. Fig. 42. * See Papers by Dr. Gulliver, in the Annals of Natural History, 3d ser. xv. et seq. DEVELOPMENT OF CELLS. 13 detected in the rind of the orange and lemon, and in the leaves of Myr- taceze and Hypericacese, When small portions of the fresh leaf of Schinus Molle are thrown on water, the resinous matter, by its rapid escape, causes them to move by jerks, and the surface of the fluid is covered with the exudation. In the bark of the Fir tribe there are cavities with thick walls containing turpentine, In the fruit of Umbellifere, canals occur called vittce (vitta, a head-band, from surrounding the fruit), containing oil. Arr-CELLS, or cavities containing air, consist either of circumscribed spaces surrounded by cells (fig. 43), or of lacune formed: by the rupture or disappearance of the septa between a number of contiguous cells, as in grasses, Equisetum, Umbelliferous plants, and pith of Walnut. They are often large in aquatic plants, and serve the purpose of floating them, as in Pontederia, Trapa, Aldrovanda, and sea-weeds. The air-cells of Limnocharis Plumieri are beautiful objects. 3.—Development and Functions of Cells, The subject of Cell-development, or Cytogenesis (xbrog, a cell, and ' yéveorc, origin), has given rise to great diversity of opinion among physiologists. We have already noticed that in the interior of grow- ing cells there is a mucilaginous matter called protoplasm, which con- tains granules. The first lining of the cell-wall arising from the protoplasm, is the primordial utricle. It forms a sort of film around the protoplasm, and in certain cases it may supply the place of the proper cell-membrane. In the protoplasm cavities are sometimes seen filled with a watery sap, and called vacuoles. In the interior of the young cell may be seen a nucleus or cytoblast (xdros, a cell, and BaAaorés, a germ), (fig. 33), composed of protoplasmic matter, and con- taining granules, called nucleoli. The nucleus often becomes attached to one side of the utricle. It is sometimes, however, retained in the centre of the cell by means of cords of protoplasm, which ultimately form the boundaries of vacuoles, or spaces containing fluid. Most physiologists think that the cyto- blast is not specially concerned in cytogenesis, but only takes part in the various chemical and other changes which occur in the contents of the cell during its growth and nutrition. , It is supposed by some that cells may be formed by the simple cageregation of granular matter, which becomes enveloped in a mem- brane, and thus forms a cell with granular contents. Dr. Bennett advocates a molecular view of cell formation. He traces cytogenesis to the presence of histogenetic (iords, veil, web, or tissue, and yéveors, origin) molecules, which unite together to form the cell-wall. New Fig. 43, Air-cells in Ranunculus aquatilis, ’ 14 DEVELOPMENT OF CELLS. cells are also produced by the division of the primordial utricle, which gradually folds inwards about the middle, forming an annular constriction, and ultimately a complete separation of the utricle into two parts. Each of these afterwards becomes covered by a permanent cell-wall. This is seen in Palmella (fig. 44). Henfrey has supported this view by observations made on the hairs of a S Tradescantia and of Achimenes grandiflora, in which @ ~®) he has traced the gradual formation eo sare Unger traces in Alge the development of new cells »@B) SS: by a fissiparous (fissus, split, and pario, I produce) Fig. 44. or merismatic (wegioudc, division) separation of the old ones into two or four divisions, in the same way as occurs in pollen, In some of the most simple plants, multi- plication takes place by a sort of sprouting of new cells from old ones, like buds from a stalk: the portion thus shooting out being afterwards separated from the parent plant by a partition. This is seen in Torula, the yeast plant. The various theories of cell-development (cytogenesis) may be re- duced to the following: 1. Formation of cells in protoplasm, existing in the interior of a cell; 2. Formation of cells in protoplasm, not Pp contained in a cell, but isolated; 3. Formation of i cells by merismatic division of the primordial utricle, or protoplasmic lining of the cell; 4. Formation of cells by a process of budding. Cells are also formed by what has been called Conjugation, or by the union of two cells, which by their mutual action give origin to a third. This is particularly seen in some of the lower Algze, such as Zygnema (fig. 45). The formation of cells goes on with great rapidity, especially in the case of fungi. From an approxi- mative calculation, it is found that in Bovista gigantea 20,000 new cells are formed every minute. Ward has noticed a similar occurrence in Phallus impudicus. In warm climates, at the commencement of the wet - season, the production of cells in the higher classes of plants proceeds with astonishing rapidity. In connection with the propagation of cellular plants much discus- sion has taken place as to the existence of their germs in the atmo- sphere, which, coming in contact with fluids of various kinds, are said to give rise to different species of fungi, such as Torula, Penicillium, , Fig. 44. Unicellular Alga (Palmella cruenta). The cell, a, absorbs, secretes, and forms new cells, by a process of fissiparous division, first into two, b b, and then into four parts, c. Fig. 45. Two filaments of a cellular plant (Zygnema), uniting together by means of tubes, p. The plant consists of a filament formed by a series of cells united in a single row. The cells, c c, appear to have different functions. Cell, s, produced by conjugation. DEVELOPMENT OF CELLS. 15 Bacterium, ete. The doctrine of biogenesis (Gos, life), panspermism ( wéty, all, oécua, seed), or the development of cells in fluid from germs introduced from the atmosphere, has been advocated by Pasteur and his followers ; while the doctrine of abiogenesis (a, privative, and Bios, life), heterogenesis (fregos, different, diverse), or what is called spon- taneous generation, has been supported by Pouchet and his followers. All that is known in regard to the growth of the lower class of plants, and their appearance in islands recently elevated by volcanic forces in the midst of the ocean, seems, independently of laboratory experi- ments, to favour Pasteur’s views.* The organised cells of plants appear to be the more immediate seats of the various changes which constitute the functions of nutrition and teproduction. In cellular plants they are the only form of elementary tissue produced throughout the whole of life. They absorb nourish- ment through their walls, elaborate secretions, and give rise to new individuals. In the newly-formed tissue of vascular plants, cells alone at first exist. Fluid matters are absorbed by them, and are transmitted from cell to cell by a process of transudation. The name of Endosmose (édov, inwards, wdéw, %, I seek), and Exosmose " (a, outwards), were given by Dutrochet to the process of transuda- tion, which leads to the motions of fluids of different densities placed on opposite sides of animal and vegetable membranes. ‘This process appears to be of universal occurrence in plants, being concerned in the movements of the sap, the opening of seed-vessels, and many other phenomena, The capsule of the Elaterium, for instance, opens with great force by a process of endosmose going on in the cells, and such is also the case with that of the Balsam. The power which cells possess of absorbing fiuids is well seen in sea-weeds, which after being dried can easily be made to assume their natural appearance by immersion in fluids. It is also observable in the spores of the Equisetum, the teeth of Mosses, the seed-vessels of some Fig-mari- golds, the Rose of Jericho (Anastatica), and some Lycopodia. Various organic secretions, which are necessary for growth and nourishment, are formed by the internal membrane of cells. It is in cells that the azotised and unazotised matters are deposited, which are afterwards applied to the purposes of vegetable life. In them we meet with the protein compounds, albumin, fibrin, and casein, consisting of carbon, oxygen, hydrogen, and nitrogen, with proportions of sulphur and phosphorus ; as well as starch, gum, sugar, oil, and colouring matters, in which no nitrogen occurs. Some of the organic matters found in plants have been artificially formed by chemical means, while others have as yet only been met with in the living organism, Spiral cells sometimes contain air. * See Professor Lister on Bacteria, in Medical Journal, October 1873; and Dr. Petti- grew’s Lecture on Physiology, in Lancet, 15th November 1873. 16 FORM AND ARRANGEMENT OF VESSELS. Section II.—Vascutar TIssvE. 1, Form and Arrangement of Vessels. VascuLaR TIssvE, or Angienchyma (d&yyos, a vessel), consists of tubes, whose length greatly exceeds their breadth. These may be formed of membrane only, or of membrane altered in various ways by deposits of fibre, or of thickening matter. Frsrovs Tusss, or Lignrous Tissue, Pleurenchyma (wreugd, a rib, from its firmness), (fig. 46), consists of tubes, or, according to some, elongated cells, of a fusiform (fusws, a spindle) or spindle-like shape (fig. 3), having their walls thickened so as to give great firm- ness. This form of tissue does not exist in cellular plants. Some have called this tissue Prosenchyma, a term, however, generally ap- plied to shortened fusiform cells only. Pleurenchyma- tous vessels lie close together, overlap each other, and, by their union, give strength and solidity to the plant. Their membrane becomes thickened by successive deposits of layers of cellulose and sclerogen, and in a transverse section the tubes present the appearance of concentric circles, occasionally with intervals, where the ligneous _| matter is deficient (fig. 47). The wood of trees is made “| |?| up of fibres or tubes of this kind, and they are found in :| the inner bark, and in the veins of leaves. The fibrous tissue may be separated from the cellular parts of plants by maceration. In this way Flax and Hemp are pro- cured, as well as the Bast used for mats. The strength of the fibres of different plants varies. Thus, New Zea- land Flax, the produce of Phormium tenax, is superior in tenacity to Common Hemp; while the latter, in its turn, excels Common Flax, as well as Pita Flax, which is the produce of Agave americana. Linen is formed from woody tissue. Cotton, on the other hand, consists of elongated cells or hairs, the membrane of which be- comes contracted in the process of drying, so as to appear twisted when viewed under the microscope. By this cha- racter mummy cloth was shown to be composed of linen. Fibrous tissue, in fabric, forms muslin, lace, etc. (some fine Indian muslins only are formed from this tissue ; other muslins are made of cotton); when reduced to small fragments they constitute the pulp whence paper is made, ay ano * ts Se Fig. 46. Fibres of Pleurenchyma, from Clematis Vitalba. Fig. 47. Transverse section of the same. FORM AND ARRANGEMENT OF VESSELS. 17 In their ordinary form, Pleurenchymatous tubes have no definite markings on their walls; but in some instances markings present themselves in the form of simple discs (fig. 48), or of discs with smaller circles in the centre (fig. 49). These dises occur in the wood of Firs, Pines, and Winter’s bark, which has received the name of glandular or punctated woody tissue. The markings are formed by concave depres- sions on the outside of the walls of contiguous tubes, which are closely applied to each other, forming lenticular cavities between the vessels, like two watch-glasses in apposition, and when viewed by transmitted light they appear like discs (fig. 48). In the centre of the depression there is a canal, often funnel-shaped, and the part of the tube corresponding to it being thus io Figs. 49, 50. thinner than the surrounding texture, gives the aspect of a smaller circle in the centre (fig. 49). When a thin section is made through two parallel lines of punctations, the slits or fissures are seen which give rise to the appearances mentioned (fig. 50). That these markings are cavities between the fibres was proved by Quekett in the case of fossil pine wood, where he separated lenticular masses of solid matter from the discs. There is sometimes observed a thicken- ing layer, in the form of a spiral fibre, surrounding the discs more or less completely, as in the yew. The discs are usually arranged in single rows, but they occur also in double and triple rows, as in Araucaria, where the markings alternate with each other. Frsro-VascuLaR Tissvx, or Trachenchyma (trachea, windpipe ; rgayvs, rough), is formed of membranous tubes tapering at each end, less firm than Pleurenchyma, and either having a fibre coiled up spirally in their in- terior, or having the membrane marked with rings, bars, or dots, arranged in a more or less spiral form. TRUE SPIRAL VESSELS (spirotdea, trachew), constituting the typical form, present themselves as elongated tubes clustered together, overlapping each other at their conical extremities, and having a spiral fibre or fibres surrounding the interior of the cylinder (fig. 51). Their outer mem- brane is thin, and consists of cellulose, At the point 5 58. Fig. 48. Woody tubes, with circular spots where the membrane is thin, Bignonia. Fig. 49. Punctated woody tissue, with double circles or dises, from common Scotch fir. Fig. 50. Lon- gitudinal section of the same, showing the union between the fibres, and the mode in which the circles are formed. Fig. 51. Two spiral vessels united. Fig. 52. Simple trachea, with fibre uncoiled. Fig. 53. Spiral vessel with a ribband of united fibres (Pleiotrachea),from the Banana, Cc 18 FORM AND ARRANGEMENT OF VESSELS. where they overlap, it is sometimes absorbed, so as to allow direct com- munication between the vessels. The fibre or spiral filament is generally single, forming simple trachew (fig. 52); but sometimes numerous fibres, varying from two to more than twenty, are united together, as in the banana, assuming the aspect of a broad ribband (fig. 53), and constituting Pleiotrachea (wheswy, more). The fibre is elastic, and can be unrolled. This can be seen by taking the leaf of a Pelargonium, and after making a superficial cut round the stalk, pulling the parts gently asunder, when the fibres will appear like the threads of a cobweb. Spiral vessels were first noticed as early as 1661, by Henshaw. They occur principally in the higher classes of plants, and are well seen in annual shoots, as in Asparagus ; in the stems of Bananas and Plantains, where the fibres may be pulled out in handfuls, and used as tinder; in many aquatics, as Nelumbium and Nymphea; and in Lili- aceous plants. In hard woody stems they are principally found in the sheath sur- rounding the pith, and they are traced from it into the leaves. They are rarely found in the wood, bark, or pith. Spiral vessels occasionally exhibit a branched ap- pearance. This may arise from the union of separate vessels in an angular or jointed ’ 3 manner, as where a leaf or branch is given one eS ae (fig. 54, wa), or it may depend on a regular division of the fibres, as is seen in the Mistleto, House-leek, and Gourd (fig. 55). The fibre is on the inside of the membrane. Quekett has shown this in silicified spiral vessels, where the mark of the spital was on the outside of the mineral matter filling the tube. The fibre usually turns from left to right, if we suppose the observer placed in the axis of the tube (fig. 56), or from right to left, if we suppose him looking at the vessel in its natural position. The fibre retains its direction throughout the length of the vessel. When | examined under the microscope there is often the appear- Figs. ance of the crossing of fibres (fig. 56), in consequence of 56. 57. the transparency of the membrane, and the observer seeing the fibre on each side of the vessel at the same time. In twining plants, the direction of the fibre does not always correspond with Fig. 54. Spiral vessels, united so as to have a branched appearance. Fig. 55. Branch- ing fibre, from spiral vessels of Gourd (Cucurbita Pepo). Fig. 56. Spiral vessels. Coils seen on both sides. Fig. 57. Coils of fibre, much separated in trachea of Gourd. FORM AND ARRANGEMENT OF VESSELS. 19 that of the stem. The coils of the spiral fibre may be close together (fig. 52), or be separated (fig. 57). Sometimes they become united together, and to the membrane of the tube, so that they cannot be unrolled. Such vessels are called closed trachem, or closed ducts, and are-seen in ferns. Fatse orn Spurious TRACHEA, the ducts of some authors, are vessels in which the internal fibre does not form a complete spiral coil. The chief varieties are annular, reticulated, and scalariform vessels, or ducts. In annular vessels (annulus, a ring), the fibres eS COC CC Fig. 58. Fig. 59. Fig. 60. Fig. 64. Fig. 63. form complete rings round the tubes (fig. 58). They resemble the tracheze: of animals more than spiral vessels do. The rings are by no means regular ; they may be horizontal or inclined, simple or forked (fig. 59), placed near to each other or separated by considerable intervals, the intermediate spaces being sometimes occupied by a fibre of an elongated spiral form, which is continuous with the rings or distinct from them (fig. 60). All these forms are easily recognised in the common Balsam. Occasionally, the ring becomes very much thickened in a direction perpendicular to the walls of the vessel, so as to leave only a small space in the centre, as in some of the Cactus tribe. When separate fibres cross each other, forming a kind of net- work on the walls of the tubes (fig. 61), the vessels become reticulated Figs. 58, 59, 60. Annular vessels from the stem of the Common Balsam. Fig. 61. Spiral vessel. Wide coil, and fibre dividing. Fig. 62. Vessel showing rings of fibre and dots. Fig. 63. Scalariform vessel from the Vine. Fig. 64. Prismatic scalariform vessel from Royal Fern (Osmunda regalis). 20 FORM AND ARRANGEMENT OF VESSELS. (reticulum, a net); and the name dotted is sometimes applied when the fibre is so broken up as to leave small isolated portions adhering to the membrane (fig. 62). In scalariform vessels (scala, a ladder), there are short horizontal lines or bars, composed of fibre, arranged along the sides of the tubes, at nearly equal distances, like the steps of a ladder, and presenting a striated ‘appearance. In some cases, as in the Vine (fig. 63), they are composed of tubes united to each other by thin, broad, oblique extremities ; at other times they taper like spiral vessels. They generally assume a prismatic form, the angles being unmarked by lines, as is seen in Ferns (fig. 64). Pirrep VesseLs.—Another kind of vessel common in plants is the pitted vessel, so called from the appearance of pits or depressions on its surface. The tissue formed by pitted vessels has received the name of Vasiform tisswe, Pitted tissue, Bothrenchyma, or Taphrenchyma (Bébgos or régeos, a pit), The vessels are of large size, and are easily observed in the Vine (fig. 65), Sugar Cane, Bamboo, Gourd (fig. 116 ter), and other plants, in which the sap circulates rapidly. They consist of cylinders more or»less elongated, in which the thickening matter is so deposited as to leave part of the membrane un- covered, thus giving rise to the porous or pitted appearance. The uncovered portions of membrane are sometimes absorbed in old vessels, and a direct communica- tion is established between them. The pits or so-called pores have sometimes a bordered aspect, which, according to Schleiden, depends on air contained in-+he cavities between contiguous ves- sels, Pitted or porous vessels are usually united to each other by a broad and often oblique septum. This kind of vessel occasion- ally presents a beaded appearance, as if formed by pitted cells, with distinct constrictions at their point of union (fig. 67). This arti- culated Bothrenchyma is by some considered as a form of cellular tissue (fig. 22). To vessels exhibiting contractions of this kind, whether spiral or pitted, the terms moniliform (monile, a necklace), or vermiform (vermis, a worm), have been applied; and the tissue com- & ff ao q Fig. 65. Fig. 66. Fi Fig. 65. Pitted vessel (Bothrenchyma) from the Vine, showing its connection with woody fibres, and the broad septa or partitions of the vessel itself. Fig. 66. Pitted vessel from Traveller’s joy (Clematis Vitalba). Fig. 67. Moniliform pitted vessels from the Common Balsam. : . ' DEVELOPMENT OF VESSELS, 21 posed of these moniliform vessels has been denominated phileboidal (pAz}, PAEBic, a vein). Laticirerovs VussEts (latex, fluid, and fero, I bear) form the tissue called Cinenchyma (xwéw, I move, from movements observed in their contents). They are the Milk-vessels, and the Proper vessels of old authors, and have been particularly described by Schultz. They consist of long, branched, homogeneous tubes, having a diameter of about rzsoo of an inch, which unite or anastomose freely (fig. 68), thus resembling the vessels of animals. At first the tubes are very slender and uniformly cylindrical (fig. 69 a); but afterwards they enlarge and present irregular distensions at different parts of their course (figs. 69 6, 70), giving rise to an articulated appearance. Their walls vary in thickness, and are not marked by any depressions or Fig. 68. Fig. 70. fibres. These vessels are met with in the inner bark, and they con- tain a granular fluid called Jutec, which is at first transparent, but often becomes of a white, yellow, or reddish colour. Some suppose that these vessels are simply intercellular canals lined with a con- tinuous membrane, containing a peculiar fluid. The tissue can be easily examined in the India-rubber tree, in Dandelion, Lettuce, and Celandine, and in various species of Ficus and Euphorbia. 2. Development and Functions of Vessels, : The simple cell is the form in which vegetable tissue first makes its appearance. It is the primary form of all the textures subsequently Fig. 68. Laticiferous vessels (Cinenchyma) from Euphorbia dulcis. Figs. 69, 70. Vessels of Latex from Celandine (Chelidonium majus). 4 22 _ FUNCTIONS OF VESSELS. produced in vascular plants. To the elongation of cells, and the deposition of thickening layers and fibres in their interior, the various vessels owe their origin. Thus when cells are elongated, as spindle- shaped tubes, and their walls are thickened and hardened by depo- sitions of ligneous matter, they give rise to Pleurenchyma ; and when elongated membranous tubes are strengthened by spiral fibres, the different kinds of Fibro-vascular tissue are produced. The spiral vessel may be considered as the type of the last-mentioned tissue, and all its varieties may be traced to different conditions in de- velopment of the fibre. In the case of some vessels, their forma- tion can be distinctly traced to cells placed end to end, the partitions between which have been ab- sorbed. The moniliform or beaded appearance often presented by the different kinds of vessels, more espe- cially the Pitted, plainly indicates this mode of for- mation. Occasionally cellular prolongations are seen in the interior of pitted vessels, giving rise to what has been called Tylosis (rbAos, swelling or protru- us" sion), It has been noticed in the vessels of Oak, Fig. 71. Chestnut, Walnut (fig. 71 a), Ash, Elm, ete. As in cells, so in vessels, the walls are composed of cellulose, and there are usually no visible perforations ; the communication between them taking place by imbibition or osmose. In some instances, when vessels are closely applied to each other, especially when they overlap, the membrane becomes absorbed, and direct communication takes place. This has been seen in spiral and pitted vessels, The pits or depressions on the walls of vessels, and the thinning of the tissue at particular points, appear to serve the purpose of allowing the rapid transmission of fluids. Pleurenchyma, in its early state, contains fluids, and conveys them from one part of the plant to another. In the progress of growth, the secondary deposits obliterate the vessels, as in the perfect or heart wood of ordinary trees. These deposits are often of a very hard nature, and assume particular colours in different kinds of trees. From the firmness of this tissue, it is well fitted to give solidity to the stems and to strengthen the eaves of plants. In Spiral vessels, the fibre adds to their elasticity, and keeps the tubes always pervious, The fibre, when once formed, does not increase much in thickness, and the secondary deposits do not obliterate the canal. Various opinions have prevailed regarding the contents of these vessels. The name Trachex, given by Grew and others, was partly from their structure, and partly from the idea that they contained air. The accurate experiments of Bischoff lead to the conclusion that the perfect spiral Fig. 71. Longitudinal section of the stem of a species of Walnut (Juglans cinerea), showing ylosis in pitted vessels, a. FUNCTIONS OF VESSELS. 23 vessels convey air, which often contains an excess of oxygen in its composition. Hales showed that air was evolved from the vessels of the Vine when cut, and Decandolle thought that part of the air in these vessels was derived from the pores of the leaves. Hoffman from his experiments concludes that spiral vessels in the ordinary state contain air, but that when a large quantity of fluid is applied to the leaves it enters the spirals. Other authors look upon these vessels as conveying fluids, while a third set maintain that both air and fluids are present, the air being derived in part from decompositions going on in the interior of the plant. The other kinds of vascular tissue, and especially the pitted vessels, are the means by which the fluids taken up by the roots of plants are conveyed to the leaves, and to all parts of the plants. Laticiferous vessels contain, according to Schultz, the elaborated sap or latex on its return from the leaves to the bark. This latex is either transparent or opaque, colourless or coloured. These vessels, when examined with the microscope in the living plant, exhibit movements in their fluid contents of a peculiar kind, which will be considered under Cyclosis, The cell has been already shown to be the type of all the tissues of plants, and to be the basis of all vegetable structure. It is of equal im- portance as regards function. In the lowest plants, as the Palmella (Protococcus) nivalis, or the Alga found in red snow, and other species of Palmella (fig. 44), also in Nostoc and Hematococcus, cells constitute the whole substance, and perform all the functions of life ; they absorb and assimilate, thus performing the functions of nutrition and secretion, and they form new cells, thus reproducing individuals like them- selves. When a more complex structure exists, as in the higher tribes of plants, certain cells are appropriated for absorption, others are con- cerned in assimilation, and others in forming and receiving secretions. When a certain degree of solidity is required to support the stem, leaves, and flowers, ligneous matter is deposited, and bast fibres are formed. When the transmission of fluids and air is carried on rapidly, the elastic fibres of the fibro-vascular tissue seem to keep the elongated cells and vessels pervious, and when the elaborated sap is conveyed continuously without interruption, anastomosing tubes occur in the form of laticiferous vessels. Cells and vessels are thus differ- entiated for the performance of special functions. TABULAR ARRANGEMENT OF VEGETABLE TISSUES. A.—Cellular Tissue (Parenchyma), composed of membrane, or of membrane and fibre, having the form of vesicles whose length does not greatly exceed their breadth. 1. Membranous Cellular Tissue ; cells formed by membrane alone, of varying thickness, but without markings on it ; when thickened and fusiform they constitute prosenchyma, composed of bast cells. 24 ARRANGEMENT OF VEGETABLE TISSUES. 2. Pitted Cellular Tissue; cells formed by membrane, which has been un- equally thickened in such a way as to leave rounded depressions at regular intervals. 8. Fibrous Cellular Tissue (Inenchyma) ; cells formed by membrane and fibre ; occasionally formed by fibre alone. a. Spiral Cells, with a complete spiral fibre inside. b. Dotted Cells, with opaque spots, which are isolated portions of fibre. B.—Vascular or Tubular tissue (Angienchyma), composed of cylindrical tubes, which are more or less continuous, and usually overlap each other, or are united by broad oblique extremities. I. Membranous Vascular Tissue ; tubes formed by membrane alone, of varying thickness, but without markings on it. 1. Ligneous Tissue (Pleurenchyma), composed of fusiform tubes with thick- ened walls, 2. Laticiferous Tissue (Cinenchyma), composed of tubes which anastomose, often present irregular dilatations, and convey a peculiar fluid, called Latex ; this tissue may be formed by intercellular canals lined with a continuous membrane, II. Pitted Vascular Tissue ; tubes formed by membrane, with markings of a more or less circular form on their walls. 1. Pitted Vessels (Bothrenchyma or Taphrenchyma) ; large pitted tubes usually ending in broad extremities, the markings on their walls de- pending on internal depressions. This tissue sometimes exhibits con- tractions at regular intervals, as if formed of cells placed end to end, and then is called Moniliform, or Beaded (Articulated Bothrenchyma). 2. Punctated Vessels (Glandular Woody Tissue) ; fusiform woody tubes, the markings on the walls depending on external depressions, and pre- senting the appearance either of single or double circular discs. III. Fibro-Vascular Tissue, composed of tubes in which the thickening matter is deposited in the form of spiral fibres, rings, bars, or dots. a. Perfect Fibro-Vascular Tissue, composed of tubes, in which there is a complete spiral fibre. _ : 1. Spiral Vessels (Trachez, Trachenchyma), in which the spiral fibre is elastic, and may be unrolled. 2. Closed Spiral vessels, or closed Trachez, in which the spiral fibre is brittle, or its coils so united to each other, and to the membrane, that they cannot be unrolled. b. Imperfect Fibro-Vascular Tissue, composed of tubes marked by rings, lines, or dots, but without a complete fibre inside. 1, Annular Vessels or Ducts, having fibres in the form of detached rings, which are occasionally united by portions of fibre. 2. Reticulated Vessels, having fibres which cross each other, or are disposed so irregularly as to form a network. 8. Scalariform Vessels, having their walls marked by isolated portions of fibre, in the form of ladder-like bars. 4, Dotted Vessels, having their walls marked by isolated portions of fibre in the form of opaque dots or points. Any of the vessels included under the Fibro-vascular tissue may exhibit con- tractions at regular intervals, so as to become moniliform. .two layers ; a superficial called ORGANS OF NUTRITION OR VEGETATION. 25 CHAPTER II, COMPOUND ORGANS FORMED BY THE TISSUES, Some plants consist of cells only, which continue throughout life to produce new cells, and to perform all the vital functions. The great mass of flowering plants, however, although originally cellular, pro- duce organs composed of cells and vessels variously arranged, and ° covered by an epidermis. These compound Organs may be divided into Nutritive, or those concerned in the nourishment of the plant ; and Reproductive, or those which are employed in the production of new individuals. The former consist of the stem, root, and leaves ; the latter, of the flower and fruit. Section ]L—Orcans or NUTRITION oR VEGETATION. 1.—Structure, Arrangement, and Special Functions, Under this head will be considered the tissues of which the various nutritive organs are composed, the mode in which the parts are arranged, and the particular function which each of the ‘organs performs. ‘ General Integument. GENERAL IntreGuMENT is the name given to the external cellular covering of plants. It can be ‘easily detached from ?young leaves and stems, usually in the form of a colourless trans- parent membrane. By pro- longed maceration it has been shown to consist frequently of Cuticle or Pellicle (fig. 72 pp), and a deep layer, usually called *- the Epidermis (fig. 72 ee). Dr. Carpenter thinks that the term epidermis should be dropped as regards plants. . He applies the term cuticle to the general integument. Tur SUPERFICIAL CUTICLE or PELLICLE (cutis and pellis, Fig. 72, General integument of a leaf of Iris germanica, pp, The Cuticular pellicle with slits, f, lying upon the proper epidermis, ¢ e, formed of hexagonal cells, and furnished with stomata, ss, 26 SUPERFICIAL CUTICLE OR PELLICLE. skin) is a very thin continuous membrane, which is spread over all parts except the openings called stomata ; in some cases entering these openings, and lining the cavities beneath them. It is formed from the epidermal cells below it. Treviranus, Schleiden, and Payen, consider it as a secretion on the outside of the cells, while Moh] and Henfrey look upon it as com- posed of the altered primary walls of the cells. Mitscherlich regards it as a corky substance, which preserves the humidity of the plant by preventing the evaporation of moisture. This substance is considered by him to be an im- portant constituent of the cell-wall. In many plants we meet with a corky epidermis com- posed of cells containing air. The cork cells h are flat and thin-walled; and in some cases Fig. 73. they can be peeled off, as in the cork oak. In fig. 73 the pellicle is represented as detached from the leaf of the cabbage, forming a sheath over the hairs, hhhh, and leaving slits, ss, corresponding to the openings of the stomata. The pellicle is perhaps similar to the intercellular substance sur- rounding cells, and to the definite mucus (collenchyma) which is seen in seaweeds (fig. 29 0). It is possible that this matter, in place of being produced on the outside of cells, may be formed within them, and ultimately deposited externally by passing through their parietes. On the inner surface of the pellicle the impressions of the epidermal cells are sometimes observed. The pellicle is the only layer of in- tegument which is present in aquatic plants, and in some of the lower trikes. THe Eprpermis (é7/, upon, and dégua, skin), (fig. 72 ¢ ¢), is ex- tended over all the parts of plants exposed to the air, except the stigma. The internal cavities of seed-bearing organs are lined by a delicate membrane, termed Epithelium (éq/, upon, 8&AAesv, to flourish). On the extremities of newly-formed roots the integument consists of loose cells, which are either the ordinary cellular tissue of the plant, or an imperfectly-formed epidermis, which has received the name of Epiblema (é/, upon, and BAymu«, wound, as being the tissue which first covers wounds). This latter kind of tissue occupies the place of the epidermis, in the parts of plants which are always under water. The cells forming the sheath of young roots are often densely filled with granular protoplasm, and contain nuclei. They become coloured in Beale’s carmine solution, On the aerial roots of Orchidaceous Fig. 73. Pellicle of Cabbage, detached by maceration, covering the hairs, hhhh, and having openings, s s, corresponding to the stomata. EPIDERMIS. 27 plants, there is an epidermal layer consisting of spiral cells (fig. 23), containing air. The epidermis is usually formed by a layer or layers of compressed cells, which assume a more or less flattened tabular shape, and have their walls bounded by straight or by fiexuous lines. Fig. 72 ee, represents an epidermis formed of regular hexagonal cells; fig. 75, one composed of irregular hexa- gons ; while in fig. 74 the bound- aries of the cells, e, are flexuous and wavy. The cells of the epi- dermis are so intimately united together, as to leave no inter- cellular spaces (fig. 77 ¢ e). The epidermis is sometimes thin and soft, at other times dense and hard. In the former case it may be easily detached from the subjacent cells; in the latter the sa cells have become thickened by de- ici posits, and sometimes the layers are so produced as to leave uncovered spots, which communicate with the interior of the cell by canals passing through the thickening layers, as in Cycas. In Rochea falcata (fig. Fig. 75. Fig. 76. © 76), the epidermis, ¢ ¢, consists of two layers of cells—the outer ones large, the inner small. The epidermis of Agave and Hoya is thickened by numerous secondary deposits ; such is also the case with that of the branches of the mistleto. The cells of epidermis are usually filled with colourless fluid, but they sometimes contain resinous and Fig. 74. Epidermis, from lower surface of the leaf of Madder (Rubia tinctorum). e, Cell of the Epidermis. s, Stoma. Fig. 75. Epidermal layer, from upper surface of a leaf of Ranunculus aquatilis when growing out of water. ee, Epidermal cells. ssss, Stomata. Fig. 76. Vertical section of lower epidermis of the leaf of Rochea falcata. ¢¢, Double epider- mal layer, with very large external cells, small internal ones, pierced by a stoma, s, which communicates with a lacuna, 7. p, Parenchyma of the leaf. 28 STOMATA. other substances. Waxy matter is occasionally found in the epi- dermis, silica is met with in the integument of grasses and Equiseta, and carbonate of lime in that of Chara. The colour of the epi- dermis generally depends on that of the subjacent parenchymatous cells, from which it can be separated as a colourless layer. The epidermal cells are usually larger than those of the tissue below them ; but sometimes, for instance in Ficus elastica, they are smaller. Sromata (oréwa, a mouth) are openings existing between some of the cells of the epidermis on parts exposed to the air. They consist usually of two semilunar cells surrounding an oval slit or orifice (figs. 72 ss, 74 s), supposed to resemble the lips and the orifice of the mouth. Stomata open or close according to the state of moisture or dryness in the atmosphere,— these changes depending on the hygroscopic character of the cells. By examining, under the micro- scope, thin stripes of epidermis in a moist and dry state, it will be seen that in the former case the lips are distended, they assume a crescentic or arched form, and leave a marked opening between them ; while in the latter they collapse, approach each other, and close the orifice. : The cells surrounding the openings of stomata are sometimes numerous, as in Marchantia. In, Ceratopteris thalictroides, Allman observed stomata formed by three cells; two of which, in their open condition, are crescentic and concave inside, while the third surrounds them, except at a small space at the end of the long axis of the stoma, and has on this account been called peristomatic (wegi, around). In Ficus elastica four cells form the stoma. In Equisetum, the stomata, which are about sév of an inch in their greatest diameter, consist of four pieces ; two of which are arched and thick at their outer convex margin, becoming thin at their inner concave edge, where two other bodies occur, having numerous processes like the teeth of a comb, hence called pectinate (pecten, a comb). Occasionally the stomatic cells become united, so as to appear in the form of an uninterrupted rim ; and at other times the stoma is a minute orifice in the walls of a cavity. Stomata communicate with intercellular spaces (figs. 76 s, 77 s), the connection being sometimes kept up by means of a funnel-shaped prolon- gation inwards of the cuticle, called, by Gasparrini, a cistoma (x/orn, a cyst or bag, and oréwa,a mouth), They are scattered over the surface of the epidermis in a variable manner. Sometimes they are placed at regular intervals corresponding to the union of the epidermal cells (fig. 72 s); at other times they are scattered without any apparent order (figs. 74, 75); and in other instances they are united in sets of two or three, or in clusters at particular points, as may be seen in Begonia, Saxifraga (fig. 78 s s), Crassula, and some Proteaces., Stomata occur on the green parts of plants, especially on the leaves STOMATA. 29 and their appendages. They are, however, also met with on parts not green, as on coloured sepals or petals, as those of the Marsh Mari- gold and Ornithogalum. They have also been seen on internal organs, as the replum of some cruciferous plants, They are not usually found in Fig. 77. Fig. 78.7 cellular plants, nor in plants always submerged, nor in pale parasites. This is not, however, a universal rule, for stomata have been detected in Marchantia and some other Cellulares ; also in the submerged leaves of Eriocaulon setaceum,.and in the pale parasite Orobanche Eryngii. They do not exist on roots, nor in plants kept long in darkness so as to be blanched or etiolated, and they are rare or imperfectly developed in succulent plants, Stomata vary in their form. The oval form is very common, and may be easily seen in Lilia- ceous plants ; the spherical occurs in Oncidium altissimum and the Primrose, the quadrangular in Yucca and Agave. In the Ole- ander, in connection with the sto- mata, there are cavities in the epi- Fig. 79. dermis protected by hairs (fig.79s), The development of stomata has been traced by Mirbel and Mohl. In the Hyacinthus orientalis, they appear first between the epidermal cells in the form of quadrangular spaces containing granular matter, which gradually collects towards the centre of the space, where a sep- Fig. 77. Vertical section of epidermis, from the lower surface of the leaf of Madder, showing the intimate union of the epidermal cells, ¢ ¢, the loose subjacent parenchyma, p, with intercellular canals, m, and lacuna, 1. s. Stoma. Fig. 78. Epidermis of leaf of Saxi- fraga sarmentosa, showing clusters of stomata, s s, surrounded by large epidermal cells, ¢ e. The cells among which the stomata occur are very small, Fig. 79. Vertical section of lower epidermis of the leaf of Neriwm Oleander. ¢, Epidermis composed of several layers of cells. p, Parenchyma of the leaf. s, Cavity filled with hairs, at the bottom of which is a stoma. : 30 EPIDERMAL APPENDAGES—HAIRS. tum or partition is formed. This septum ultimately splits, leaving a slit or opening which constitutes the stoma. Mohl has traced this process throughout the same leaf in different stages of growth. In Mar- chantia, Mirbel found several tiers of cells forming the stoma, and he supposed that the opening was produced by the absorption of a central cell, leaving the others to form the rim or border. : The number of stomata varies in different parts of plants. They are most abundant on the under surface of leaves exposed to the air, and are often entirely wanting on the upper surface, more especially when it has a dense shining cuticle. In floating leaves the stomata, when present, are on the upper surface only. When plants usually under water are made to grow for some time in the air, their leaves exhibit stomata, When leaves grow vertically, the stomata are often equal in number on both sides. The number of stomata varies from a few hundreds to many thousands on a surface of one inch square. The following table exhibits the number of stomata in the leaves of a few plants :— STOMATA IN ONE INCH SQUARE OF SURFACE OF THE LEAF. Upper Side. Under Side. Mistleto (Viscum album) Z ‘ : 200... 200 Spiderwort (Tradescantia) . : » 2,000 ... 2,000 Rhubarb (Rheum palmatum) . . - 1,000... 40,000 Crinum amabile . : ji ‘ . 20,000 ... 20,000 Aloe . : ‘ : ‘ : . 25,000 ... 20,000 Carnation (Dianthus Caryophyllus . 38,500 ... 38,500 Yucca . . ‘ ‘ ‘ ‘ . 40,000 ... 40,000 Mezereon (Daphne Mezereum) ; - None. aie 4,000 Peony . : 7 ‘ é z . None. -. 18,000 Agave americana . é A c - None. wee 1,560 Holly (Ilex Aquifolium) ‘ . None. ... 68,600 Olive (Olea europea) . ¢ ‘ . None. ... 57,600 Potamogeton natans. 3 ‘ 7,800 ... None. Victoria regia * ‘i . é - 21,600 ... | None. Vine (Vitis vinifera). : : - None. .. 18,600 Cherry-laurel (Laurocerasus communis) . None. .» 90,000 Lilac (Syringa vulgaris) . ‘ : . Few. «. 160,000 APPENDAGES OF THE EPIDERMIS, or APPENDICULAR ORGANS.— The epidermis frequently exhibits projections or papille on its surface, in consequence of some cells being enlarged in an outward direction (fig. 76 ¢ ¢). When these assume an elongated or conical form they constitute hairs (pili or villi). Harrs, then, are composed of one or more transparent delicate cells proceeding from the epidermis, and covered with the cuticle (fig. 73), They are erect (fig. 80 ¢), or oblique, or they lie parallel to the sur- face, and are appressed. Sometimes they are formed of a single cell, which is simple and undivided (fig. 80), or forked (fig. 81) or EPIDERMAL APPENDAGES—HAIRS. 31 branched (fig. 82); at other times they are composed of many cells either placed end to end, as in moniliform or necklace-like hairs (fig. 83), or united together laterally, and gradually forming a cone, as in ¥ Fig. 80. Fig. 81. Fig. 82. compound hairs (fig. 84), or branched (fig. 85). When several hairs proceed from a common centre, they become stellate (stella, a star), or radiated (fig. 86). The latter arrangement occurs in hairs of the Mallow tribe, and is well seen in those of Deutzia scabra, and on the stem of the Rice-paper plant (Fatsia papyrifera). When stellate hairs are placed closely together, so as to form a sort of membranous ex- pansion (fig. 87), a scale or scurf is produced. In Bromeliacee the scurfiness of the leaves is a marked character. To such expansions of the epidermis the name lepis (Aewic, a scale) is applied, and the surface is said to be lepidote. These scales have sometimes a beau- in e Fig. 84. Fig. 85. Fig. 86. tiful silvery appearance, as in Eleagnus and Sea-buckthorn (fig. 87). Surrounding the base of the leaves of Ferns, a brown chaffy substance Figs. 80-86. Forms of hairs. e, Epidermis. 80. Simple hair formed of a single, undi- vided, elongated, and tapering cell, 81. Forked or bifurcate hairs of Sisymbrium Sophia, formed by one cell of the epidermis, e, dividing into two. 82. Branched hair of Arabis alpina, formed by a simple hair of the epidermis, -e, dividing into numerous conical cellular branches. 83. Moniliform hair, from Lychnis chalcedonica. Fig. 84. Partitioned, unbranched hair, from stem of Bryonia alba. Fig. 85. Partitioned, branched hair, from flower of Nicandra anomala. Fig. 86. Stellate or star-like hair, from leaf of Althea rosea. EPIDERMAL APPENDAGES—HAIRS, occurs, consisting of elongated cells, to which the name of ramentaceous hairs, or ramenta (ramentum, a shav- ing), has been given. In Palms also a similar substance (but of firmer tex- ture) occurs, called reticulum (reticulum, a net), or mattulla, (matta, a ‘iat Prickles or aculei, as in the Rose, are hardened hairs connected with the epidermis, and differ from spines or thorns, which have a deeper ori- gin, Sete are bristles or stiff hairs, and the surfaces on which they occur are said to be setose or setaceous, Some hairs, as those of Drosera, or sundew (fig. 88), have one or more spiral fibres in their interior. * Various names have been given to the different forms of hairs; they are clavate or club-shaped (clava, a club), gradually expanding from the base to their apex ; capitate, having a distinct rounded head ; rough or scabrous, with slight projections on their surface ; hooked or wneinate (uncus, a hook), A with a hook at their apex pointing downwards and to one side; barbed or glochidiate (yAwyic, a barb), with i Fig. 87. Scale or scaly hair, from leaf of Hip- A pophaé rhamnoides. Fig. 88, Drosera dichotoma, i double-leaved sundew, showing leaves covered with glandular hairs. The gland is terminal, and there is a spiral fibre inside the stalk supporting the land. Fig. 88 ee EPIDERMAL APPENDAGES—HAIRS. 33 two or more hooks around the apex; shield-like or peltate (pelta, a buckler), when attached by their middle, and projecting horizontally on either side, as in Malpighia urens (fig. 89), and in many cruciferous plants ; ciliated (ctlium, an eyelash), when surrounding the margin of leaves, On the pod of the Cowitch (Mucuna pruriens), hairs are pro- duced with projections on their sur- face, which cause irritation of the skin. In Venus’ Fly-trap (Dionea muscipula), stiff hairs exist on the blades of the leaf (fig. 202 e), which, when touched, cause their closure. Hairs occur on various parts of plants ; as the stem, leaves, flowers, seed-vessels, and seeds, and even in the interior of vessels. In the interior of the spathe of some palms numerous ovate cells, analogous with hairs, occur in clusters, and when the spathe is dried they can be shaken out in the form of powder. Cotton consists of the hairs sur- rounding the seeds of Gossypium herbaceum and other species of Gossy- pium. Hairs are developed occasionally to a great extent on plants exposed to elevated temperatures, as well as on those growing at high altitudes. When occurring on the organs of reproduction they are connected with fertilisation, as the hairs on the style of Goldfussia, and the retractile hairs on the style of Campanula. Different organs of plants are transformed into hairs; as may be seen in the flowering stalks of the Wig-tree (Rhus Cotinus), and in the calyx of Composite. Names are given to the surfaces of plants according to the presence or absence of hairs, as well as the nature of the hairs which cover them. The followimg are the more important terms :— Glabrous, smooth, having no hairs; hairy (pilosus), furnished with hairs ; pubescent, covered with soft, short, downy hairs ; villous, having long, weak, often oblique hairs; sericeous, covered with long, closely ap- pressed hairs, having a silky lustre ; hispid (hispidus, hirtus), covered with long stiff hairs not appressed ; hirsute, having long tolerably dis-. tinct hairs, not stiff nor appressed ; velvety (velutinus), with a dense covering of short down, like velvet ; tomentose, covered with crisp, rather rigid, entangled hairs like cotton, which form a sort of felt (tomentum) ; woolly, with long curled and matted hairs like wool ; bearded or stupose (orien, tow), when hairs occur in small tufts. The hairs which are most frequently met with in plants are called lymphatic, from their not being connected with any peculiar secretion. Those, on the other hand, which have secreting cells at their base or apex, are denominated glandular, and are not to be distinguished from glands, under which therefore they will be considered. Lymphatic hairs occur on parts exposed to the air, and are wanting in blanched Fig. 89. Peltate hair of Malpighia urens, p p, arising from epidermis, ¢. g, The gland, which communicates with the hair. ! D Fig. 89. 34 EPIDERMAL APPENDAGES—GLANDS. plants. On young roots cellular projections occur (fig. 97 h), which may be called radical hairs. Young leaves and buds are frequently thickly covered with protecting hairs. In this instance the hairs grow chiefly along the veins ; and as the leaves increase in size, and the veins are separated, the hairs become scattered and apparently less abundant. On the parts of the flower (as in the Iris), coloured hairs occur which have been called corolline. GLANDs are collections of cells forming secretions. The term has been vaguely applied to all excrescences occurring on the surfaces of plants, They are either stalked (petiolate, stipitate), or not stalked (sessile). a The former may be called glandular hairs, having the secreting cells at the apex. Stalked glands, or glan- dular hairs, are either composed of a single cell, with a dilatation at the apex (fig. 90 a), or of several cells united together, the upper one being the secreting cell (fig. 90 6). In place of a single terminating secreting cell, there are occasionally two (fig. 90 c) or more (fig. 90 d). Hairs sometimes serve as ducts through which the secretion of glands is discharged ; these are glandular hairs, with the secreting cells .at the base. Such hairs are seen in the nettle (fig. 91), in Loasa or Chili nettle, and in Malpighia (fig. 89), and are commonly called stings. In the nettle they are formed of a single conical cell, dilated at its base (fig. 91 6), and closed at first at the apex, by a small globular button placed Fig. 90. Glandular hairs. e, Epidermis. a, Hair formed by a single cell, from Sisym- brium chilense. 6, Hairs formed of several cells terminated by a secreting cell, from flower-stalk of Antirrhinum majus. c, Hair composed of several cells, terminated by two secreting cells united laterally, from flower-stalk of Lysimachia vulgaris. d, Compound hair, terminated by several secreting cells united end to end, from Geum urbanum, Fig. 91, Conical hair of Urtica dioica, or common nettle, ending in a button or swelling, s, with a dilatation or bulb at its base, b, which is surrounded by epidermal cells, ue, In this hair there are currents of granular protoplasm, ff. EPIDERMAL APPENDAGES—GLANDS. 35 obliquely (fig. 91 s). This button breaks off on the slightest touch, when the sharp extremity of the hair enters the skin, and pours into the wound the irritating fluid which has been. pressed out from the elastic epidermal cells at the base. When a nettle is grasped with violence, the sting is crushed, and hence no injury is done to the skin. The globular apex of glandular hairs sometimes forms a viscid secretion, as in the Chinese primrose and sundew (fig. 88). The hairs of the latter plant, by this secretion, detain insects which happen to alight on them. The hairs gradually close on the insects, electrical phenomena taking place during the movement. Some think that in this case the insects are used as food by the plant. When glands are sessile, they consist of epidermal cells either surrounding a cavity or enclosing small secreting cells. In fig. 92 is represented a gland taken from the flower-stalk of Dictamnus albus, cut vertically, to show the cavity surrounded by cells, which is filled with a greenish oil ; while in fig. 93 there is a gland with a short thick stalk, full of cells, taken from Rosa centifolia, These figures show the transition from sessile to stalked glands. Some of the superficial cells of the epidermis are sometimes slightly elevated above the rest, and contain peculiar fluids. In the Ice-plant, the appearance of small pieces of ice on the surface is produced by cells containing a clear fluid, which is said to have an alka- line reaction ; in the Chick-pea, similar superficial cells contain an acid fluid. Clear glands are also seen on the under surface of the leaf of Passiflora lunata. Resinous glands are seen in the Hop and Hemp plants. Glandular depressions or pits occur, surrounded by secreting cells. At the base of the petals of the Crown-imperial, for instance, cavities are seen containing a honey-like fluid, secreted by what are called nectariferous glands. Cavities containing sac- charine matter, surrounded by small thin-walled cells, are met with in the leaves of Acacia longifolia, also in Viburnum Tinus, and Clerodendron fragrans. The cavities communicate with the surface of the leaves by means of canals, Peculiar glands are found at the inner side of the base of the petioles of Cinchona and Tpecacuan plants (fig. 94). Glands are occasionally sunk in the epidermis, so as merely to have Fig. 92, Fig. 93. Fig. 92. Gland from flower-stalk of Dictamnus albus, cut vertically, showing central cavity, 1, filled with greenish oil, and surrounded by a layer of cells, c, which contain a red juice, and are connected with the epidermis, e. Fig. 93. Gland from Rosa centifolia ; e, the epidermis. Fig. 94. Cluster of ovate-oblong cellular glands from the base of the stipule of the Ipecacuan plant (Cephaelis Ipecacuanha). 36 FUNCTIONS OF EPIDERMIS. the apex projecting ; at other times they lie below the epidermal cells, as in the Myrtle, Orange, St. John’s-wort, and Rue. In the latter case they are sometimes called vesicular, and are formed by cells sur- rounding cavities containing oil (fig. 95). When they occur in the leaves, they give rise, when viewed by transmitted light, to the appearance of transparent points or dots. Verruce, or warts, are collections of thickened cells on the surface of plants, assuming a rounded form, and containing starch or other matters. Lenticels, or Lenticular glands, are cellular projections on the surface of the bark, arising from its inner part. Trecul says that lenticels result from the formation of corky matter under decayed or decaying tissues, the corky particles surrounding sub-stomatic cavi- ties. The corky matter protects the internal tissue from injurious atmospheric influence. Other lenticels are simply cracks of the epi- dermis before the production of cork or periderm, while a third set are produced on the surface of a peridermic layer. Tur Sprcrat Funcrions of the epidermis and its appendages are to protect the parts beneath from various atmospheric and meteoro- logical influences. In plants growing in dry climates, the epidermis is often very thick, and coated with a waxy secretion, to prevent too great transpiration or exudation of fluids, In those which inhabit humid places the epidermis is thin and absorbent ; while in submerged aquatics there is no proper epidermal covering. The stomata regulate the transpiration ; opening and closing, according to the state of humid- ity and dryness of the atmosphere surrounding them. When a plant is growing vigorously, the constant passage of fluids keeps the regu- lating cells around the stomata in a distended state, and thus opens the orifice ; whereas, when the circulation is languid and the fluids are exhausted, the cells collapse and close the opening. The opinion that the succulency of plants is.a sort of dropsical condition, caused by the absence of stomata to carry off the fluids, has not been confirmed by observation. Hairs, according to their structure, serve various pur- poses. Lymphatic hairs protect the surface, and regulate evaporation. Plants thickly covered with hairs, as Verbascum Thapsus (Great Mullein), have been known to resist an extended period of drought. When organs become abortive they sometimes assume the form of hairs. Glandular hairs, and glands in general, form secretions which are em- ployed in the economy of vegetation, or are thrown off as excretions no longer fitted for the use of the plant itself. Many of these secre- tions constitute important articles of materia medica, Lenticels keep Fig. 95. Vesicular gland from Ruta graveolens, or Common Rue. 4g, Gland formed by large transparent cells, surrounding a central lacuna, 1, e, Epidermis from upper surface of the leaf. wc, wc, Cells filled with Chlorophyll. STRUCTURE OF ROOTS. 37 up & connection between the air and the inner bark, and probably per- form the function of stomata in the advanced period of the growth of the plant. They are considered by Decandolle and others as being the points where young roots are produced in certain circumstances, and on that account they have been called Rhizogens (éiZa, a root, and yewdew, to produce). They are conspicuous in Willows, the young branches of which form roots very readily when placed in moist soil. Some hairs occurring on the styles of plants are called collecting hairs, from the functions which they perform in taking up the pollen. In the species of Campanula, these hairs are so formed that after the pollen has been discharged, their upper part is drawn within the lower. In many hairs, as in the nettle, a circulation of fluids takes place, connected apparently with their nutrition and development (fig. 91). In nettle hairs and in the moniliform purple hairs on the stamens of Tradescantia, or Spiderwort, this movement may be easily seen under the microscope. The subject of the circulation in hairs will be con- sidered under Rotation, Root orn Descenpine AXIs. Structure of Roots. Before proceeding to the consideration of the special nutritive organs, the root, stem, and leaves, a few remarks are required in reference to the general division of plants into three great classes, Acotyledons, Monocotyledons, and Dicotyledons. The first of these embraces flowerless plants, -having a cellular embryo, and no seed-leaf, or, as it is called, Cotyledon. Such plants as Ferns, Mosses, Lichens, Sea-weeds, and Mushrooms, belong to this class. The second includes flowering plants having an embryo with one seed-leaf or Cotyledon, such as Lilies, Palms, Grasses ; while the third includes plants which have two seed- leaves or Cotyledons, such as ordinary forest trees, and the majority of flowering plants. In these classes there are marked differences in the structure of the nutritive organs, to the consideration of which we now proceed. In the young state there is no distinction between stem and root, as regards structure; both being cellular, and prolongations of each other in opposite directions. In stemless plants, as Thallogens, the root remains in 4 cellular state throughout the life of the plants. The root is afterwards distinguished from the stem by the absence of a provision for the development of leaf-buds, and by increasing from above ° downwards. It is not always easy to distinguish between a stem and aroot. Many so-called roots bear at their upper part a portion called their crown, whence leaf-buds arise. Underground stems and roots are often confounded. Some plants, as the Moutan Peony, the Plum-tree, 38 STRUCTURE OF ROOTS. Pyrus japonica, and especially Anemone japonica, have a power of forming buds on their roots. The last-mentioned plant develops these buds on every part of its extensively ramifying roots, which may be chopped into numerous pieces, each capable of giving rise to a new plant. Such is also the case with the annulated root of Ipecacuan. The part where the stem and root unite is the collwm or neck. In woody plants, the fibres of the stem descend into the roots, and there is an internal arrangement of woody layers, similar to that seen in the stem itself. Roots are usually subterranean and colourless. Externally, they havea cellular epidermal Govering of a delicate texture, sometimes called epiblema (p. 26), in which no stomata exist. Their internal structure consists partly of cells, and partly of vascular bundles, in which there are no vessels with fibres which can be unrolled. Roots do not ex- hibit true pith, nor a medullary sheath. The axis of the root gives off branches which divide into radicles or fibrils (fig. 96), the ex- ye Fig. 96. Fig. 97. tremities of which are composed of delicate cellular tissue, and have been erroneously called spongioles or spongelets, They are not separate organs, and have nothing of the character of a sponge. Over these root extremities a very thin layer of cells is extended, called a Pileorhiza (aw ros, a cap, and éi€a, a root). This sometimes becomes thickened, and separates in the form of a cup, as in Screw-pines (fig. 98), and in Lycopodia (fig. 138), Occasionally the extremities of roots are enclosed in a sheath, or ampulla, as in Lemna. Cellular papillz Fig. 96. Tapering root of Malva rotundifolia, giving off branches and fibrils, Fig. 97. Young root of Madder, showing cellular processes, hhh, equivalent to hairs, ve, Outer cells of the root not elongated into hairs. STRUCTURE OF ROOTS. 39 and hairs are often seen in roots, but no true leaves. These hairs consist of simple elongated cells, which occur singly, and appear to serve the purpose of absorption (fig. 97, hhh). Roots increase principally by additions to their extremities, which are constantly renewed, so that the minute fibrils serve only a temporary purpose, and represent deciduous leaves. The tissue at the extremities of roots is older and more dense than that immediately below it, so as to form a protecting covering. Roots, in some instances, in place of being subterranean, become aerial. Such roots occur in plants called Epiphytes, or air-plants (é/, upon, and gurdy, a plant, from growing on other plants), as in Orchi- dace ; also in the Screw-pine (Pandanus), (fig. 98), the Banyan (Ficus indica), and many other species of Ficus, where they assist in supporting the stem and branches, and have been called adventitious or abnormal. In Screw-pines these aerial roots follow a spiral order of development. In Mangrove trees (fig. 99) they often form the entire support of the stem, which has decayed at its lower part. The name of adventitious is applied to roots arising from the sides of stems, as for instance those which are formed when portions of stems and branches of the Willow and Poplar are planted in moist soil. They appear first as cellular projections, into which the fibres of the stem are prolonged, and by some are said to proceed from lenticels. They frequently arise from points where the epidermis has been in- jured. A Screw-pine, in the palm-house of the Edinburgh Botanic Garden, had one of its branches injured close to its union with the ’ Fig. 98, Pandanus odoratissimus, the Screw-pine, giving off numerous aerial roots near the base of its stem. Fig. 99. Rhizophora Mangle, the Mangrove tree, supported, as it were, upon piles, by its numerous roots, which raise up the stem. The plant grows at the muddy mouths of rivers in warm climates. 40 FORMS OF ROOTS. stem. This branch was at the distance of several feet above the part where the aerial roots were in the course of formation. At the part, however, where the injury had been inflicted, a root soon appeared, which extended rapidly to the earth, and then divided so as to form rootlets ; thus the branch was firmly supported. The extremities of the aerial roots of Orchids are covered with a layer of delicate whitish tissue, composed of spiral cells. This layer is called velamen radicum, or covering of the roots. Green-coloured aerial roots are frequently met with in endogenous plants. Such roots possess stomata. In the Ivy, root-like processes are produced from the stem, by means of which it attaches itself to trees, rocks, and walls. Those processes are subservient to the pur- poses of support rather than nutrition. In parasites, or plants which derive nourishment from other plants, such as Dodder (Cuscuta), roots are sometimes produced in the form of suckers, which enter into the cellular tissue of the plant preyed upon. When roots have been exposed to the air for some time, they occasionally assume the functions of stems, losing their fibrils, and developing abnormal buds. Duhamel proved this experimentally, by causing the branches of a willow to take root while attached to the stem, and ultimately raising the natural roots into the air. Forms of Roots, The forms of roots depend upon the mode in which the axis descends and branches. When the central axis goes deep into the ground in a tapering manner, without dividing, a tap-root is produced (fig. 96). This kind of root is sometimes shortened, and becomes succulent, forming the conical root of carrot, or the fusiform, or spindle- shaped root of radish, or the napiform root of turnip, or it is twisted, as in the contorted root of Bistort. When the descending axis is very short, and at once divides into thin, nearly equal fibrils, the root is called fibrous, as in many grasses ; when the fibrils become short and succulent the root is fasciculated, as in Ranunculus Ficaria and Asphodelus luteus (fig. 100) ; when the succulent fibrils are of uniform size, and arranged like coral, the root --is coralline, as in Corallorhiza innata; when some of the fibrils are developed in the form of tubercules, containing starchy matter, the root is tubercular ; the tubercules, in such cases, are in reality stem- tubers, as seen in the Jerusalem Artichoke (Helianthus tuberosus), and in Orchis (fig. 101) ; when the fibrils enlarge in certain parts only, the root is nodulose, as in Spireea Filipendula (fig. 102), or moniliform, as in Pelargonium triste (fig. 103), or annulated, as in Ipecacuan (fig. 104). Some of these so-called roots are formed of a stem and root combined, FORMS OF ROOTS, 41 and when cut in pieces they give rise to buds and new plants. This occurs in the Ipecacuan plant, Fig. 101. Fig. 100. Fig. 102. In some Dicotyledonous roots, as in the Car- rot and Beet, there is a circle of fibro-vascular bundles, which are separated by medullary rays. In the turnip these bundles are immediately under the rind, and in the inner portion of the root the bundles are separated from each other by a great development of cellular tissue. In these peculiar thickened roots it is often difficult to determine their structure. They have more of the ‘aspect of stems, and have been called Hypo- cotyledonary stems. The structure in several % fleshy Dicotyledonous roots resembles that of Fig. 104. . Monocotyledons, In Dicotyledonous plants the root, in its early state, or the radicle, as it is then called, is a prolongation of the stem, and elongates directly by its extremity. It then continues to grow in a simple or branched state (fig. 98). From this mode of root development, these plants have been called Exorhizal (2€w, outwards, and ¢/fu, a Fig. 100. Fasciculated root of Asphodelus luteus. Fig. 101. Tubercular roots or stem- tubers of Orchis. Several of the radical fibres retain their cylindrical form, while two are tubercules containing starchy matter. Fig. 102, Nodulose root of Spirza Filipendula. Fig. 103. Moniliform root of Pelargonium triste, Fig. 104. Ipecacuan (Cephaelis Ipeca- cuanha), with an annnlated root. 42 FORMS OF ROOTS. root), by Richard. In their after progress these roots follow the arrangement seen in the woody part of the stefan. In some cases, as in the Walnut and Horse-chestnut, there is a prolongation of the pith into the root to a certain extent. f ’ In Monocotyledonous plants the young root or radicle pierces the lower part of the axis (fig. 105 r), is covered with a cellular sheath, ¢ ; numerous fibrils, 7’ 7’ 7’ 7’, are then developed like adventitious roots. These plants are therefore called by Richard, Endorhizal (évéor, within) ; and the sheath is denominated Coleorhiza (norsis, a sheath). In their after progress they usually retain their compound character, consisting of fibrils, most of which often remain unbranched (figs. 100, 101). The first-formed roots which surround the axis, if the plant is perennial, gradually die, and others are produced in ‘succession farther from the central axis. In Endogenous roots, the same structure is observed asin the stem, Thus, fig. 106 represents a section of a root of a Palm, composed of cellular tissue, porous vessels, v p, modified spiral vessels, v s, fibrous or woody tissue, f, and latici- ferous vessels, 2. Roots are pushed out from various parts of the stems of many Palms, and are applied closely to the surface of the stem. Fig. 105. Grain of wheat germinating. g, The mass of the grain. #, The young stem begin- ning to shoot upwards. 7, The principal root from the axis. Lateral roots, 1’ 7’ 7’ 7’, covered, like the preceding, with small hairs or threads. Coleorhiza or sheath, cc c, with which each of the roots is covered at its base, while piercing the superficial layer of the embryo. Fig. 106. Transverse section of part of the root of a Palm (Diplothemiwm maritimum), to show the mode in which the cells and vessels are arranged. v p, Large porous vessels situated in the interior. vs, Scalariform or modified spiral vessels more external, and becoming smaller the farther they are from the centre. ff, Fibrous tissue, or elongated cells, accompany- ing the vessels, 1, Groups of laticiferous vessels of different sizes, the larger being inside. FUNCTIONS OF ROOTS. 43 In Acotyledonous -plants the young root is a development of super- ficial cells from no fixed point, and they have been called Heterorhizal '(éregos, diverse). In their subsequent progress these roots present appearances similar to those seen in the stem. They frequently appear in the form of fibres on the outer part of the stem, giving rise, by their accumulation at the base, to the conical appearance repre- sented in fig. 135, r a. Functions of Roots. Roots either fix the plant in the soil or attach it to other bodies, They absorb nourishment by a process of imbibition or endosmose (flow inward), through their spongioles or cellular ex- tremities. The experiment of Duhamel and Senebier, conducted by inserting at one time the minute fibrils alone into fluid, and at another the axis of the root alone, showed clearly that the cellular extremities were the chief absorbing parts of the roots. Hence the importance, in transplanting large trees, of cutting the roots some time before, in order that they may form young fibrils, which are then easily taken up in an uninjured condition, ready to absorb nourishment. When an acorn is put into the ground, it first sends down a long tap root. This is not well fitted for feeding young stems and leaves, and hence numerous fibrous roots appear near the surface of the ground. The more numerous these fibres the more rapid the growth. The tap root is sometimes cut about seven inches under ground at an early period, and this causes numerous fibres to be thrown out. The elongation of the roots by their extremities enables them to accommodate themselves to the soil, and allows the extremities of the rootlets to extend deeply without being injured. Roots, in their lateral extension, bear usually a relation to the horizontal spreading of the branches, so as to fix the plant firmly, and to allow fluid nutritive substances to reach the spongioles more easily. It is of importance to permit the roots to extend easily in all directions, By restricting or cutting the roots, the growth of the plant is to a certain degree prevented, although it is sometimes made to flower and bear fruit sooner than it would otherwise have done. The system of re- strictive potting, formerly practised in green-houses, often injured the natural habit of the plants. The roots filled the pots completely, and even raised the plants in such a way as to make the upper part of the root appear above the soil. To roots there are sometimes attached reservoirs of nourishment, in the form of tubercules, containing starch and gum (fig. 101), which are applied to the nourishment of the young plant. These are seen 44 FUNCTIONS OF ROOTS. in the Dahlia and in terrestrial Orchids, In epiphytic Orchids, on the other hand, the roots are aerial, and the stems are much de- veloped, forming pseudo-bulbs. Upon the roots of Spondias tube- rosa there exist round black-coloured tubercules, about eight inches in diameter, consisting internally of a white cellular substance, which is full of water. These tubercules seem to be intended to supply water to the tree during the dry season. They are often dug by travellers, each of them yielding about a pint of fluid of excellent quality. Roots also give off excretions of different kinds. These are eliminated by a process of exosmose (flow outwards), and con- sist both of organic and inorganic matter. They were examined by Macaire and Decandolle, and at one time they were thought to be injurious to the plant, and by their accumulation to cause its deterioration. It was also supposed that while they were prejudicial to the species of plant which yielded them, they were not so to others, and that hence a rotation of crops was neces- sary. Daubeny and Gyde have found by experiment that these excretions are not injurious, and it is now shown that the necessity for rotation depends on the want of certain nutritive matters in the soil,* In very rich and fertile land the same crop may be grown successively for many years, Stem or AscenpinG AXIs. Forms of Stems, The stem is that part of a plant which bears the leaves and flowers. It receives the name of Caulis in ordinary herbaceous plants which do not form a woody stem, Culm in grasses, Truncus in trees, Caudex or Stock in Palms and in some Cacti, and Stipe in Ferns. Herba- ceous stems are those of annual and biennial plants, as well as the young yearly shoots of perennial plants. Theterm haulmisprobablya - corruption of culm ; it is used by farmers to designate the stem of grasses and the herbaceous stems of plants. The stem is not always conspicuous. Plants with a distinct stem are called caulescent ;- those in which it is inconspicuous are acaules. Some plants are truly stemless, and con- sist only of expansions of cellular tissue, called a Thallus, and hence are denominated Thadlogens, or Thallophytes (@uAAds, a frond, yevvcesy, to produce, gurdy, a plant), They have no true vascular system, but are composed of cells of various sizes, which sometimes assume an elongated tubular form, as in Chara, The cells are sometimes united * This subject is considered when the sources whence plants derive their nourishment are treated of. FORMS OF STEMS. 45 in one or several rows, forming simple filaments, as in Confervee 5 or branched and interlaced filaments, as in some Fungi; or cellular expansions, as in Lichens and sea-weeds. Stems have usually considerable firmness and solidity, but some- times they are weak, and either lie prostrate on the ground, thus becoming procumbent; or climb on plants and rocks by means of rootlets like the Ivy, being then called scandent; or twist round other plants in a spiral manner like Woodbine, becoming volubile, Twining plants turn either from right to left, as the French bean, Convolvulus, Passionflower, and Dodder, Periploca, and Gourd ; or from left to right (left-handed screw), as Honeysuckle, Twining Polygonum, Hop, and Tamus. Bryony tendrils twine from right to left, and left to right, alternately. In warm climates twining plants (danas) often form thick woody stems ; while in temperate regions they are generally herbaceous. Exceptions, however, occur in the case of the Clematis, Honeysuckle, and Vine; the twining stem of the vine has been called sarmentum (sarmentum, a twig, or cutting of a vine). Some stems are developed more in diameter than in height, and present a peculiar shortened and thickened aspect, as Testudinaria or Tortoise- plant, Cyclamen, Melocactus, Echinocactus, and other Cactacez. Stems have a provision for a symmetrical arrangement of leaves and branches,—nodes (nodus, a knot), or points whence leaf-buds are produced, being placed at regular intervals. No such provision occurs in roots, which ramify irregularly, according to the nature of the soil. The intervals between nodes are called internodes, The mode in which branches come off from the nodes gives rise to various forms of trees, such as pyramidal, spreading, or weeping; the angles formed with the stem being more or less acute or oblique. In the Italian Poplar and Cypress the branches are erect, forming acute angles with the upper part of the stem; in the Oak and Cedar they are spreading or patent, forming nearly a right angle; in the weeping Ash and Elm they come off at an oblique angle; while in the weeping Willow and Birch they are pendulous from their flexibility. The comparative length of the upper and under branches also gives rise to differences in the contour of trees, as seen in the conical form of Spruce, and the umbrella-like form of the Italian Pine (Pinus Pinea), The branching of some trees is very peculiar. In the Amazon district many Myris- ' ticacese and Monimiacee have verticillate branches coming off in fives, Some Amazon trees taper remarkably downwards, so as to have a form like an inverted cone or pyramid. This is seen in the Mulatto tree (Eukylista Spruceana), one of the Cinchonacez. The buds of trees are developed in different ways. In some, such as the Oak and Birch, the terminal bud of each shoot produces yearly a new portion of the shoot, while the flowers come off from axillary buds. Again, in other trees, as Lilac and Horse-chestnut, the t 46 FORMS OF STEMS. buds at the extremity produce inflorescence, which thus terminates the axis of the shoot, while the shoots of the succeeding year are from axillary buds. When the branches of trees bearing terminal buds have the axis of the shoot destroyed by wounds or by insects, then the lateral leafy buds become developed, giving rise to anomalous appearances seen in the Birch and other trees. Plants which form permanent woody stems above ground are denominated trees and shrubs, while those in which the stems die down to the ground are called herbs. The term tree (arbor) is ap- plied to those plants which have woody stems many times exceeding the height of a man, the lower part free from branches being the trunk ; a small tree (arbusculus) is one not above 25 feet high; a shrub (frutex) has a stem about three times taller than a man, and branches from near the base: an wndershrub (suffrutex or fruticulus) does not exceed the length of the arm; while a bush (dumus) is a low diminutive shrub, with numerous branches near the base. The terms arborescent, fruticose, suffruticose, and dwmose, are derived from these. The cylindrical form of the trunk of trees is sometimes interfered with by peculiarities in the production of woody tissue. In this way protuberances are formed of various kinds, This is very remarkable in some kinds of Bombax, and in the Bottle-tree of Australia, where the whole stem appears in the form of a large flask or bottle, taper- ing to each end, and swollen in the middle. So also, by interruption to the growth of the root and other causes, knobby stems are formed, as in the Yew (fig. 128). Stems have usually around form. They are sometimes compressed or flattened laterally, while at other times they are angular: being triangular, with three angles and three flat faces; trigonous (resis, three, and ywvia, an angle), with three convex faces; triquetrous (triquetrum, a triangle), with three concave faces; quadrangular, or square; quinguangular, or five-angled ; octangular, or eight-angled, etc. Various terms are applied to the forms of stems, as cylindrical or terete, jointed or articulated—that is, with contractions at intervals, many-angled or polygonal. ‘ The stem has been called the ascending axis, from being developed in an upward direction. It does not, however, always ascend into the air; and hence stems have been divided into aerial, or stems which appear wholly or partially above ground; and subterranean, or those which are entirely under ground. The latter are often called roots, but they are distinguished by producing leaf-buds at regular intervals, Underground stems are common in Monocotyledons, and it is often found that the structure of Dicotyledonous underground stems, such as Jerusalem artichokes, resemble in structure Monocotyledons, The following are some of the more important modifications of stems :— The Crown of the root is a shortened stem, often partially under ground, FORMS OF STEMS. 47 ‘ which remains in some plants after the leaves, branches, and flower- stalks have withered. In this case the internodes are very short, and the nodes are crowded together, so that the plant appears to be stem- less. It is seen in perennial plants, the leaves of which die ‘down to the ground annually. A Rhizome or root-stock (fig. 107) is a stem which runs along the surface of the - ground, being partially cover- ed by the soil, sending out roots from.its lower side and leaf-buds from its upper. It occurs in Ferns, Iris, Hedy- Fig. 107. chium, Acorus or Sweet Flag, Ginger, Water-lily, many species of Carex, Rushes, Anemone, Lath- rea, etc. By many the term rhizome is applied to stems creeping horizontally, whether they are altogether or only partially subterranean. The short underground stem of Arum maculatum differs from the rhizome of Solomon’s Seal, in the presence of the old axes in the latter, and their decay in the former. A rhizome may then be considered as a series of corms united together, the internodes or individual axes being more or less elongated, and usually covered with leaf scales. In rhizomes, called definite, the terminal bud gives off flowers, and the lateral buds form the stem; while in indefinite rhizomes the terminal leaf-bud is formed annually. A rhizome sometimes assumes an erect form as in Scabiosa succisa, in which the so-called premorse (premorsus, bitten at the end) root is ‘in reality a rhizome, with the lower end decaying. The erect rhizome of Cicuta virosa shows hollow internodes, separated by partitions. A Pseudo-bulb is an enlarged bulbous-like aerial stem, common in Orchidaceous plants. It is succulent, often contains numerous spiral cells and vessels, and is covered with a thick epidermis. In the Kohl-rabi a peculiar thickened turnip-like stem is met with. A Soboles is a creeping underground stem, sending roots from one part and leaf-buds from another, as in couch grass, Carex arenaria, and Scirpus lacustris (fig. 108). It is often called a creeping root, but is really a rhizome with narrow elongated internodes. A Tuber is a thickened stem or branch produced by the approximation of the nodes and the swelling of the internodes, as in the potato (fig. 109 t). The eyes of the potato are leaf-buds. Tubers are sometimes aerial, occupying the place of branches, .Fig. 107. Portion of Rhizome, r, of Polygonatum multifiorum, Solomons Seal, forming buds and adventitious roots. a, A bud in the progress of development. 6, A bud developed as a branch at the extremity of the,rhizome. ce, Cicatrices or scars, indicating the situa- tion of old branches which have decayed, 48 FORMS OF STEMS. The ordinary herbaceous stem of the potato, when cut into slips and planted, sometimes sends off branches from its base, which assume the d Fig. 108. form of tubers. These tubers occasionally become nodulated, or elon- gated, or curved in various ways. Arrow-root is derived from the scaly tubers of Maranta arundinacea. In the Orchis the radicular bodies called tubercules, or by some tubers, belong to the root system (fig. 101). In the didymous (twin) tubers of Orchis mascula, we find at the end of the season one of them withered, while the other is vigorous, and bears a bud at its apex. The lowest leaf of this bud gives rise to another bud, and when the oldest tuber decays this new one enlarges, and next season be- comes the bud-tuber, while its parent pro- duces the flowering stem. A Cormisa solid underground stem which does not spread by sending out shoots, but remains of a rounded form, and is covered by thin scales on the outside (fig. 110). The scales are modified leaves specially developed on subterraneous stems, and they may produce buds in their axils, The corm occurs in Colchicum, Crocus, and Fig. 110. Fig. 108. Soboles, or creeping subterranean stem, 7, of Scirpus lacustris. fe, fe. Scales or modified leaves on the stem. pa, Aerial portion of the plant. tt, Level of the earth. Fig. 109. Lower portion of a potato plant. ss, Level of earth. pa, pa, Aerial portion” bearing leaves. t, Subterranean portion, showing stem-tubers. 7, Tuber showing eyes or leaf- buds, covered by scales, 6, which are equivalent to leaves. Fig. 110. Corm or under- ground stem of Colchicum autumnale. +, Roots. f, Leaf. «’, Ascending axis of preceding year, withered. a", Axis of the year. a’”, Point where axis of next year would be formed. — STRUCTURE OF STEMS. 49 Gladiolus. A Corm’is only of one year’s duration, while a rhizome or root-stock consists of a string of annual growths, persistently con- nected. It is distinguished from a root by sending off buds annually in the form of small corms or thickened branches, either from the apex, as in Gladiolus, or from the side, as Colchicum (fig. 110 a”), These buds feed on the original corm a’, and absorb it. In the Crocus, after flowering, may be seen the withered parent corm; new corms, which are in reality the basis of the flowering axis, branching from the old corm; and in the axil of the leaves of the flowering stem small buds ready for another season. In Colchicum autumnale (Meadow Saffron), we find in autumn the flowering stem united to the side of the corm at its base. The two lowest sheaths of the flowering stem produce buds in their axils. The flowering stem withers, and the internodes between the two buds form a new corm, while the old one decays. Internal Structure of Stems, Stems, according to their structure, have been divided into three classes :— Exogenous (¢&w, outward, and ysvvéew, to produce), when the bundles of vascular tissue are produced regularly in succession exter- nally, and go on increasing indefinitely in an outward direction. Endogenous (évdov, within), when the bundles of vascular tissue are produced in definite bundles and converge towards the interior, addi- tions being thus in the first instance made internally. Acrogenous (éxeos, summit), when the vascular bundles are developed at the same time and not in succession, the addition to the stem depending on the extension of the growing point or summit. The plants which exhibit these three kinds of stem are distinguished also by the structure of their embryo. Thus exogenous stems are met with in plants having an embryo or germ which has two cotyledons or seed-lobes, hence they are called Dicotyledonous (d/¢, twice, and xorvAnday, a seed-lobe); plants with endogenous stems have only one cotyledon, and are called Mono- cotyledonous (4.6v0g, one) ; while plants with acrogenous stems have no cotyledons, and are called Acotyledonous (a, privative). The terms connected with the embryo will.be afterwards fully explained. Exogenous or Dicotyledonous Stem. ‘The Exogenous or Dicotyledonous stem characterises the trees of this country. It consists of a cellular and vascular system ; the for- mer including the outer bark, medullary rays, and pith ; the latter, the inner bark, woody layers, and medullary sheath. In the early stage of growth the young dicotyledonous stem is entirely cellular ; but ere long fusiform tubes appear, forming bundles, having the E 50 EXOGENOUS OR DICOTYLEDONOUS STEM. appearance of wedges (fig. 111 ww) arranged in a circle round a cen- tral cellular mass of pith (fig 112 p), which is connected to the outer part or bark by means of cellular processes called medullary rays (fig. lll rrr). At first the cellu- lar portion is large,—the pith, bark, and rays occt- pying a large portion of the stem ; but by degrees new vascular bundles are formed, which are deposited be- tween the previous ones (fig. 112 nnn). By this means the pith is more cir- cumscribed, the medullary rays become narrow, and the bark more defined. Such is the structure presented by an annual herbaceous dicotyledonous stem, consisting of pith, a circle of fibro- vascular and woody tissue, medullary rays, bark, and epidermis. The stems of trees and shrubs in their young state exhibit an arrangement similar to that represented as occurring in the herbaceous stem (fig. 112), with this difference, that the vascular circle is more firm and solid. As ligneous stems continue-to grow, further changes take place by which their diameter is increased, and they are rendered more dense. The shoots or young branches given out annually, how- ever, are similar in structure to annual herbaceous stems; and in making successive sections from the apex of a branch, which is suc- culent and green, to the base of a trunk, which is comparatively dry and hard, the various changes which take place can be easily traced. Fig. 113 represents a horizon- tal or transverse section of the upper part of a young branch of Acer campestre. In the centre, m, is the pith, very large at this period of growth, and occupying Fig. 111. Fig. 112. Fig. 113. Fig. 111. Young Dicotyledonous or Exogenous stem. w w, Vascular bundles in the form of wedges. p, Pith. rr 7, Medullary rays. Fig. 112. Same stem further advanced ; the letters as in fig. 111, nnn, New vascular wedges interposed between those first formed. Fig. 113. Horizontal section of young stem of Acer campestre, magnified twenty- six diameters. m, Pith. em,em, Medullary sheath. fb, fb, woody bundles. v p, Pitted vessels. rm, Medullary rays, c¢, Cambium or zone of tissue between the xylem or wood portion, and phloem or bark portion. fe, Fibresof Endophleum. » 1, Laticiferous vessels. ec, Cellular envelope, Mesophleum. p, Corky envelope, Epiphleum, e p, Epidermis. EXOGENOUS OR DICOTYLEDONOUS STEM. 51 at least one-half of the whole diameter, its cells diminishin g in size as they approach the circumference. Immediately surrounding the pith is a layer of a greenish hue, the medullary sheath, em, from which the medullary rays, rm, proceed towards the circumference, dividing the vascular circle into numerous compact segments, which consist of woody vessels, f b, and of pitted vessels, vp. These are surrounded by a moist layer of greenish cellular tissue, c, called the cambium layer, which is covered by three layers of bark, fc, ec, and p, with laticiferous vessels, v 2, the _ whole being enclosed by the epidermis, ep. On making a thin vertical section of a portion of the same branch, and viewing it under the microscope, the parts composing the different portions become more obvious (fig. 114). The pith, m, with its hexagonal cells decreasing Fig. 115. , in size outwards, surrounded by a narrow fibro-vascular zone, the medullary sheath, consisting chiefly of spiral vessels, ¢; the medullary ray, rm; the vascular zone, consisting of pitted vessels, v p, of large diameter, and forming the large round apertures seen in a transverse section ; the fibres of the wood, f 2, with their thick walls and smaller apertures ; the inner bark or liber, f c, with the layer of cambium cells, c; the second layer of bark, or the cellular envelope, ec, with the laticiferous vessels, v 2; the outer or suberous layer of bark, p, with the thin layer of epidermis, ¢ p, having hairs scattered over its surface. A transverse section of a bundle of vascular tissue of a dicotyledonous plant, magnified 230 times, is represented in fig. 115. The arrow indicates the direction from within outwards. We here perceive the vascular bundle surrounded by a large-celled tissue (246 f). The Fig. 114, Vertical section of the same stem more highly magnified. ¢, Trachez or spiral vessels. fl, fl; fl, Woody fibres. The other letters as in fig. 113. Fig. 115. Transverse section of a bundle of vascular ‘tissue of a Dicotyledonous plant. ad, Epidermis. b, Large- celled tissue of bark. e¢, Fibres of bast layer. d, d’, Woody layers and laticiferous vessels of inner bark, d’, Cambium cells. gg, and hh, Large pitted vessels. e, Woody tubes. Jf, Large cells, 52 EXOGENOUS OR DICOTYLEDONOUS STEM. quadrangular cells, a é, form the epidermis, to which succeeds the cellular tissue of the bark, b. The latter surrounds a bundle of bast (phloem) fibres, c, and ligneous layers of inner bark, with laticiferous vessels, d d', which are separated, in the direction towards the interior, by a layer of cambium cells, d’, from the proper vascular tissue (xylem), consisting of pitted vessels with thick walls, g g, and others with thin walls, hh, mixed with woody tubes, e. Such is the structure of a young shoot during the first year of its growth. At the end of a second year the shoot is found to have increased in diameter by the formation of a zone of vessels consisting Fig. 116: Se up- ee we OF Fig. 116 di. of porous and woody tissue, and a zone of fibrous bark, the medullary rays being at the same time continued from within outwards. This is represented in fig. 116, where 1, 1 indicates the section of the stem of the first year’s growth (the letters referring to the same parts as in figs. 114, 115); and 2 shows the interposed zones of the second year, by which the diameter of the stem is increased. Tue Pra, or the central part of a dicotyledonous stem, is com- Fig. 116. Vertical section of a branch of common maple (Acer campestre) two years old, where (1, 1) indicates the portion formed the first year, and (2) that formed tle second. The letters as in figs. 114 and 115. Fig. 116 bis. Certain parts of the preceding magnified, in order to show the structure of the vessels and cells, as well as their form and direction. Fig. 116 ter. A portion of a pitted vessel from the gourd, magnified. EXOGENOUS STEM—PITH. 53 posed of cellular tissue, which is developed in an upward direction, the cells diminishing in size towards the circumference, and being often hexagonal. In the young plant it occupies a large portion of the stem, and sends cellular processes outwards at regular intervals to join the medullary rays (figs. 111,112 p). The pith has at first a greenish hue, and is full of fiuid, but in process of time it becomes pale- coloured, dry, and full of air. These changes take place first in the central cells. Sometimes the pith is broken up into cavities, which have a regular arrangement, as in the Walnut, Jessamine, and Cecropia peltata ; it is then called discoid or disciform (d/oxoc, a disc, from the circular parti- tions). At other times, by the rapid growth of the outer part of the stem, the pith is ruptured irregularly, and forms large cavities as in the fistular stem of Umbelliferous plants. Cireumscribed cavities in the internal cellular portions of stems are by no means unfrequent, arising either from rupture or absorption of the cells. In some rare instances vessels occur in pith, as in Elder, Pitcher-plant, and Ferula ; and occasionally its cells are marked by pores indicating the formation of secondary deposits. The extent of pith varies in different plants, and in different parts of the same plant. In Ebony it is small, while in the Elder it is large. In the Shola plant, Auschynomene aspera, the interior of the stem is almost entirely composed of cellular tissue or pith ; from this a kind of rice-paper is made, and light hats. The same kind of tissue occurs in the Papyrus of the Nile. Large pith is also seen in Fatsia papyrifera, or Chinese rice-paper plant. When the woody circle of the first year is completed, the pith remains stationary as regards its size, retaining more or less its dimensions, even in old truriks, and never becoming obliterated. Tae Meputtary Suzarta is the fibro-vascular layer immediately surrounding the pith. It forms the inner layer of the vascular bundle of the first year (fig. 114 ¢), and consists chiefly of true spiral vessels, which continue to exercise their functions during the life of the plant, and which extend into the leaves. With the spiral vessels there are a few woody fibres intermingled. The processes from the pith are pro- longed into the medullary rays between the vessels of the sheath. Woopy Layers.—During the first year the vascular circle con- sists of an internal layer of spiral vessels forming the medullary sheath, and external bundles of pitted and ligneous vessels. In subsequent years the layer of spiral vessels is not repeated, but concentric zones of pitted vessels (fig. 116 ter) and pleurenchyma are formed, consti- tuting what are commonly called the woody circles of trees. The vascular bundles, from their mode of development in an indefinite manner externally, have been called Exogenous; and, for the same reason, Schleiden has denominated them Indefinite, Exogenous plants have sometimes received the name of Cyclogens (xinAos, a circle), in consequence of exhibiting concentric circles in their stems, Ona 54 EXOGENOUS STEM—WOOD. transverse section, each zone or circle is usually seen to be separated from that next to it by a well-marked line of demarcation. This line, as in the Oak (figs. 117, 118), and in the Ash, is indicated by holes which are the openings of large pitted vessels ; the remainder of the tissue in the circle being formed by pleurenchyma, with thickened walls and of smaller calibre, In some trees, as the Lime, Hornbeam, and Maple, the line is by no means so well marked, as the openings are smaller and more generally diffused ; but there is usually a deficiency of pitted vessels towards the outer part AW ZE ) of the circle. In cone-bearing plants, : as the Fir, in which the woody layers consist entirely of punctated woody tissue (fig. 49), without any large pit- ted vessels, the line of separation is marked by the pleurenchyma becoming dense and often coloured. In some kinds of wood, as Sumach, the zones are separated by a marked development of cellular tissue. The separation between the zones is said to be owing to the interruption in the growth of the tree during autumn and winter, and hence it is well defined in trees of temperate and cold climates. But even in tropical trees, the lines, although often inconspicuous, are still visible; the dry season, during which many of them lose their leaves, being their season of repose. The woody layers vary in their texture at dif- ferent periods, At. first the vessels are pervious and full of fiuid, but by degrees thickening layers are deposited which con- tract their canal, and sometimes obliterate it. The first-formed layers are those which soonest become thus altered. In Fig. 117. Horizontal section of the stem of an oak eight years old. b, Wood, showing concentric circles or zones, separated by points which correspond to the opening of the large pitted vessels, or Bothrenchyma. ¢, Bark, showing also eight concentric’ circles, thinner and less distinct. The wood and bark are traversed by medullary rays, some of which extend from the bark to the pith, and others reach only a certain way inwards. Fig. 118. Horizontal section of two woody bundles of Cork-oak, separated from each other by the medullary ray, rm’. The two primary bundles are divided by secondary rays, rm”, rm”, rm”, which vary in extent according to the period when they originated. m, Pith. ec, Cellular envelope, p, Corky envelope, which is highly developed, and exhibits several layers, Fig. 117. Fig. 118. EXOGENOUS STEM—woop., 55 old trees, there is a marked division between the central Heart-wood or Duramen (durus, hard), and the external Sap-wood or Alburnum (albus, white): the former being hard and dense, and often coloured, with its tubes dry and thickened; while the latter is ‘less dense, is of a pale colour, and has its tubes permeable by fluids. The difference of colour between these two kinds of woods is often * very visible. In the Ebony tree, the duramen or perfect-wood is black, and is the part used for furniture, while the alburnum is pale; in the Beech, the heart-wood is light-brown ; in the Oak, deep-brown ; in Judas tree, yellow ; in Guaiacum, greenish. The alteration in colour is frequent in tropical trees. In those of temperate climates, called white-wood, as the Willow and Poplar, no change in colour takes place; this is also the case in the Chestnut: and Bombax. The relative pro- portion of alburnum and duramen varies in different trees. Duhamel says that in the oak, six inches in diameter, the alournum and duramen are of equal extent ; in a trunk one foot in diameter they are as two to seven; in a trunk two feet in diameter, as one to nine. The heart-wood is more useful than the sap-wood, and less liable to decay. The wood: of different trees varies much in its durability. Pieces of wood 28 inches square, were buried to the depth of one inch in the ground, and decayed in the following order :—Lime, American Birch, Alder, and Aspen, in three years ; Willow, Horse-chestnut, and Plane, in four years ; Maple, Red Beech, and Birch, in five years; Elm, Ash, Hornbeam, and Lom- bardy Poplar, in seven years; Robinia, Oak, Scotch Fir, Weymouth Pine, Silver Fir, were decayed to the depth of half an inch in seven years ; while Larch, common Juniper, Virginian Juniper, and Arbor Vite, were uninjured at the end of that time. From the mode in' which the woody layers are formed, it is obvious that each vascular zone is moulded upon that which precedes it; and as, in ordinary cases, each woody circle is completed in the course of one year, it follows, that, by counting the concentric circles, the age of a tree may be ascertained. Thus fig. 117 represents an oak eight years old, having eight woody layers, 6. This computation can only be made in trees having marked separations between the circles. There are, however, many sources of fallacy. In some instances, by interruption to growth, several circles may be formed in one year, and thus lead to an erroneous estimate. Care must be taken to have a complete section from the bark to the pith, for the circles sometimes vary in diameter at different parts of their course, and a great error might occur from taking only a few rings or circles, and then estimating for the whole diameter of the tree. When by the action of severe frost, or other causes, injury has been done to the tender cells from which’ the young wood is developed, while, at the same time, the tree continues to live, so as’ to form perfect woody layers in subsequent years, the date of the injury may be ascertained by counting the 56 EXOGENOUS STEM—CAMBIUM. number of layers which intervene between the imperfectly formed circle and the bark. In 1800, a Juniper was cut down in the forest of Fontainbleau, exhibiting near its centre a layer which had been affected by frost, and which was covered by ninety-one woody layers, showing that this had taken place in the winter of 1709. Inscriptions made in the wood become covered, and may be detected in after years when a tree is cut down; so also wires or nails driven into the wood. As the same development of woody layers takes place in the branches as in the stem of an Exogenous tree, the time when a branch was first given off may be computed by countipg the circles on the stem and branch respectively. If there are fifty circles, for instance, in the trunk, thirty in one branch and ten in another, then the tree must have been twenty years old when it produced the first, and forty when it formed the other. : In Exogenous stems the pith is not always in the centre. The layers of wood on one side of a tree may be larger than those on the other, in consequence of their fuller exposure to light and air, or the nature of the nourishment conveyed, and thus the pith may become excentric. Zones vary in size in different kinds of trees, and at different periods of a plant’s life. Soft wooded trees have usually broad zones, and old trees form smaller zones than young ones. There are certain periods of a plant’s life when it seems to grow most vigorously, and to form the largest zones. This is said to occur in the oak between twenty and thirty years of age. CamBium. — External to the woody layers, and between them and the bark, there is a layer of mucilaginous semifluid matter, which is particularly copious in spring, and to which the name of Cambium (cambio, I change, from the alterations that take place in it) has been given (figs. 113, 114 c). In this substance cells are formed, called cambium cells, of a delicate texture, in which the protoplasm and primary utricle are conspicuous. These cells undergo changes, so as to assume an elongated fusiform shape, and ultimately become thick- -ened pleurenchyma. So long as the primary utricle can be detected they appear to be in an active state, and capable of developing new cells. This cambium layer marks the separation between the wood and the bark, and may be regarded as constituting the active forma- tive tissue of Dicotyledonous stems. It constitutes the thickening zone, by means of which the stem is enlarged—the cambium cells situated most internally being subservient to the purposes of the wood forma- tion, while the external ones give origin to the new bark. According to Schacht this is the proper nourishing tissue. BaRK oR Corvicat (cortex, bark) System lies external to the wood, and, like it, consists of several layers. In the early state it is entirely cellular, and is in every respect similar to the pith ; but as the vascular bundles are developed, the bark and pith are separated, and the former EXOGENOUS STEM—BARK. 57 gradually becomes altered by the formation of secondary deposits. The bark consists of a cellular and vascular system. In this respect it resembles the wood, but the position and relative proportion of these two systems is reversed. In the bark the cellular system is external, and is much developed ; while the vascular is internal, and occupies comparatively a small space. The cellular portion of the bark con- sists of an external layer, or Epiphleum (é/, upon, on the outside, and pros, bark), and the cellular envelope, or Mesophlawm (£00¢, middle) ; while the vasular system forms the internal portion called Liber, or Endophieum (évéoy, within). The inner bark, or endophleum (fig. 116 f c), is composed of elongated pleurenchyma mixed with laticiferous vessels and some cellular tissue. It is separated from the wood by the cambium layer. The pleurenchymatous tubes are thickened by concentric deposits in their interior, and thus they acquire a great degree of tenacity. The liber of the Lime tree and of Antiaris saccidora (the sack tree of Coorg) are used to form mats, cordage, and bags ; and the toughness of the fibres of the inner bark of flax, hemp, and of many of the nettle and mallow tribe, render them fit for various manufacturing purposes. The liber is sometimes, from its uses, called the bast-layer, Occasionally it is continuous and uninterrupted, as in the Vine and Horse-chestnut ; at other times, as in the Oak, Ash, and Lime, the fibres are separated during the progress of growth, and form a sort of network, in the interstices of which the medullary rays are seen. The fibres of the lace-bark tree (Lagetta lintearia) are similar. In figure 119 is represented the bark of Daphne Laureola; jf indicating the woody fibres of liber, and r the medullary rays. The en- dophleeum increases by layers on its inside, which are thin, and may be separated like the leaves of a book, and hence the application of the name liber. The term liber may be derived from the fact of the inner bark being used for writing upon. The cellular envelope, or mesophiewm, lies immediately on the outside’ of the liber. It consists of polyhedral, often prismatical cells (fig. 116 ec), usually having chlorophyll, or green colouring matter, in their interior, but sometimes being colourless, and containing raphides. They are distinguished from those of the epiphleum by their form and direction, by their thicker walls, their green colour, Fig. 119. Fig. 119. Network formed by liber of Daphne Laureola. ff, Fibrous bundles. rr, Medullary rays. 58 EXOGENOUS STEM—BARK,. and the intercellular spaces which occur among them. This covering is usually less developed than the outer suberous layer, but sometimes, as in the Larch and common Fir, it becomes very thick, and separates like the epiphleum. In the cellular envelope laticiferous vessels occur. The Zpiphiaum is the outer covering of the bark, consisting of cells which usually assume a cubical or flattened tabular form (fig. 116 bis, p). The cells have no chlorophyll in their interior, are placed close together, and are elongated in a horizontal direction ; and thus they are distinguished from the cells of mesophleum. In the progress of growth they become often of a brown colour. This cover- ing may be composed of a single layer of tabular cells; but in some trees it consists of numerous layers, forming the substance called cork, which is well seen in Quercus Suber, the Cork-oak (fig. 118 p) ; hence the name suberous, or corky layer, which is given to it. The form of its cells varies in some instances, being cubical at one part, and more compressed or tabular at another, thus giving rise to the appearance of separate layers. After a certain period (sometimes eight or nine years), the corky portion becomes inactive, and is thrown off in the form of thickish plates, leaving a layer of tabular cells or periderm below. On the exterior of the epiphloum is situated the epidermis, which has already been described. It is formed of a layer of cells, which in woody stems serve only a temporary purpose, becoming ultimately dry, and being thrown off in the form of plates or shreds. The bark, in its increase, follows an order exactly the reverse of that which occurs in the woody layers. Its three portions increase by additions to their inside. The layers of liber owe their increase to the cambium cells, which, by their constant reproduction, mark the separation between the vascular bundles of the wood and the fibres of the endophleeum. These layers are often so compressed and united together as to be counted with difficulty, while at other times they are separated by rings of cellular tissue, and thus remain conspicuous. In the case of the cellularportions of the bark there are also succes- sive additions, sometimes to a great exent, but they do not usually éxhibit any marked divisions. As the additions are made to the woody layers on the outside, and to the bark on the inside, there is a constant distension going on, by which the bark becomes compressed, its layers of liber are condensed, the fibres are often separated (fig. 119) so as to form meshes (as in the lace-bark), its epidermis is thrown off, and the epiphlcum is either de- tached along with it, or, when thick, is ruptured in various ways, 80 as to give rise to the rugged appearance presented by such trees as the Elm and Cork-oak. In some instances the bark is very disten- sible, and its outer cellular covering is not much developed, so that the surface remains smooth, as in the Beech. The outer suberous layer sometimes separates with the epidermis, in thin plates or scales. EXOGENOUS STEM—RAYS. 59 In the Birch, these have a white and silvery aspect. There is thus a continual destruction and separation of different portions of the bark. The cellular envelope and liber may remain while the epi- phlceum separates, or they also may be gradually pushed off—the parts which were at first internal becoming external. In the case of some Australian trees, both the cellular and fibrous portions are detached in the form of thin flakes, and occasionally each annual layer of liber pushes off that which preceded it. The epidermis separates early, and no renewal of it takes place. There is, however, an internal covering, which is formed of various portions of the bark. To this covering the name Periderm (eg, around, and déeua, skin) has been given by Mohl. From the mode ip which the outer layers of bark separate, it fol- lows that inscriptions made on them, and not extending to the wood, gradually fall off and disappear. A nail driven into these layers ulti- mately falls out. In consequence of the continued distension of an exogenous stem, it is found that woody twining plants cause injury, by interrupting the passage of their fluids. Thus a spiral groove may be formed on the surface of the stem by the compression exercised by a twining plant, such as honeysuckle: From what has been stated relative to the changes which take place in the bark, it will be under- stood that it is often difficult to count its annual, layers, so as to esti- mate the age of the tree by means of them. This may, however, be done in some cases, as shown at fig. 117, where there are eight layers of bark, e, corresponding to eight woody layers, 6. MeEpuLLARY Rays orn Prats. — While the bark and pith become gradually separated by the intervention of vascular bundles, the connection between them is kept up by means of processes called medullary rays (figs. 111, 112 r). These form the silver grain of carpenters ;- they communicate with the pith and the cellular envelope of the bark, and they consist of cellular tissue, which becomes com- pressed and flattened so as to assume a muriform appearance (fig. 120 mr). At first they occupy a large space (fig. 111 r); but as the vascular bundles increase they become more and more narrow, forming thin lamine or plates, which separate the woody layers. On making a transverse or horizontal section of a woody stem, the medul- lary rays present the aspect of narrow lines running from the centre to the circumference (figs. 117, 118 7 m); and in making a vertical section of a similar stem through one of the rays, the appearance represented in fig. 120 will be observed, where a medullary ray, m 1, composed of flattened muriform cells, passes from the pith, p, to the cellular envelope, ¢ e, crossing the trachez of the medullary sheath, ¢, the ligneous tissue, J, the pitted vessels of the wood, }, and the fibres of the liber, cf, The laminee do not by any means preserve an unin- terrupted course from the apex to the base of the tree, They are 60 ANOMALOUS EXOGENOUS STEMS. broken up by the intervention of woody fibres, as seen in a vertical section of a woody stem (fig. 121), tangentially to the medullary rays m7, m1, m7, which are separated by similar interlacing fibres, (2. The medullary rays are usually continuous from the pith to the Fig. 121. bark, additions being made to them as they proceed outwards. But, occasionally, secondary rays arise from the outer cells, which pass only to a certain depth between the vascular bundles, as in the Cork- oak (fig. 118, 7 m," 7m"). Medullary rays are conspicuous in the Cork-oak, Hazel, Beech, Ivy, Clematis, Vine. They are not so well marked in the Lime, Chestnut, Birch, Yew. Anomalies in the Strueture of the Exogenous Stem. The stems of Dicotyledonous plants occasionally present anomalous appearances in the structure and arrangement of their wood, bark, and medullary rays. In place of concentric circles there are some- times only a few rows of wedge-shaped vascular bundles produced during the life of the plant, additions being made by the interposition of bundles of a similar kind annually, resembling in this respect the formation of woody bundles in the early growth of herbaceous plants (fig. 112). In the Pepper tribe, Aristolochiaceze, and Menisper- macez, these anomalous stems occur. In Gnetum (fig. 122), the Fig. 120. Vertical section of a one-year old branch of Acer campestre, highly magnified, and extending from the pith to the bark, parallel to the medullary rays. mr, A medullary ray or plate extending from the pith, p, to the bark, ¢ e, crossing trachee, t, fibres of xylem or wood, J, pitted vessels, b, and cortical fibres,c f. Fig. 121. Vertical section of the same branch at right angles to medullary rays. 11, fibres of wood (xylem) which interlace, leaving spaces, mr, mr, mT, where the medullary rays pass. ANOMALOUS EXOGENOUS STEMS. 61 vascular bundles, 6 6 db 6, form zones, which are each the produce of several years’ growth, and are separated by layers, 110001, which may be con- sidered as representing dif- ferent zones of liber. In some of the Meni- spermum tribe, the sepa- rating layers are of a cellular and not of a fibrous nature. In Banisteria nigrescens fig. 123), the young stem 1) presents a four-lobed surface ; the lobes become more evident (2); and ul- timately (3) the stem is divided into a number of separate portions, the central one of which alone exhibits pith and medullary rays. The portions are separated by interposed cortical layers. : Many of the Malpighiacez, Sapindacez, and Bignoniacex of Brazil, exhibit stems in which the woody layers are arranged in a very irre- 3 Fig. 122, Fig. 123, gular manner. In the stem of Calycanthus floridus, and of some Fig. 122.—Horizontal section of stem of Gnetum. m, Pith. e m, Medullary sheath. 6bbbb, Woody bundles forming seven concentric zones, each of which is the produce of several years, 1112111, Fibres of liber forming interposed circles, equal in number to the woody zones. Fig. 123, Horizontal section of stem of Banisteria nigrescens at different ages. 1. Stem presenting four superficial lobes. 2. Six more marked lobes, with inter- mediate divisions. 3, The lobes separated by cellular tissue, the middle one alone having pith and medullary sheath. The dots indicate the orifices of pitted vessels. 62 ANOMALOUS EXOGENOUS STEMS. Brazilian Sapindacez, such as Paullinia pinnata (fig. 124), Serjania triternata and Selloviana, there is a central woody mass with from three to ten small secondary ones round it. ach of the masses con- tains true pith, derived either from the cortical cellular tissue, or from the original medullary centre. Gaudichanud and Jussieu state that around these separate collections of pith there is a medullary sheath and spiral vessels. No annual rings have been detected in the secondary masses, but medullary rays exist usually in their outer portion (fig. 124). In these anomalous Sapindacez, the central and Fig. 126. Fig. 127. lateral woody masses are enclosed in a common bark, with a continuous layer of liber. Some have supposed that the lateral masses are un- developed branches united together under the bark ; but Treviranus Fig. 124. Horizontal section of the stem of Paullinia pinnata, one of the Sapindaces of Brazil, showing numerous secondary woody masses surrounding a central one. Each of the separate masses has pith, often excentric, with a medullary sheath, containing spiral vessels, and a few medullary rays chiefly towards the circumference of the stem. Fig. 125. Horizontal section of the stem of Bignonia capreolata, showing the crucial division of the woody layers. Fig. 126. Horizontal section of stem of Heteropterys anomala, one of the Brazilian Malpighiacez, showing an irregularly lobed surface. The dots indicate porous vessels. Fig. 127. Fragment of a stem of climbing species of Banisteria (B. scandens), showing the effects of compression. ANOMALOUS EXOGENOUS STEMS. 63 considers them as connected with the formation of leaves, and as depending on a peculiar tendency of the vascular bundles to be de- veloped independently of each other round several centres. In some Bignoniacee (fig. 125), the layers of wood are di- ‘vided in a crucial manner into four wedge-shaped portions by the intervention of plates differing in texture from the ordinary wood of the plant, and probably formed by introversion, or growing inwards of the liber. In some Guayaquil Bignonias, Gaudichaud perceived first four of these plates, next eight, then sixteen, and finally thirty-two. In Aspidosperma excelsum (Paddle-wood) of Guiana, and in Heteropterys anomala (fig. 126), the stem assumes a peculiar lobed and sinuous aspect ; and in some woody climbing plants, pres- sure causes the stems to become flattened on the side next the tree on which they are supported, while from being twisted alternately in different directions, they present a remarkable zigzag form, having the woody layers developed only on one side (fig. 127). In Firs the wood is occasionally produced ‘in an oblique in place of a per- pendicular manner, thus injuring _ the timber, and causing it to split in an unusual way. The young plants produced from the seed of such twisted-wooded firs are said to inherit the peculiarity of their pa. rents. Occasionally the dicotyledonous stem, be- comes swollen at certain places, especially near the root, and thus exhibits a tuberous appear- Fig. 128. Swollen stem of Irish Yew (Taxus baccata, var. stricta). Fig, 128. 64 ENDOGENOUS OR MONOCOTYLEDONOUS STEM. ance, as shown in fig. 128, which represents an Irish yew with an anomalous stem. This peculiar appearance is said to be liable to occur in coniferous plants grown from cuttings. A Sequoia (Welling- tonia) gigantea is mentioned in which a tuberous mass was produced 1 foot 6 inches in circumference, on a plant grown from a cutting, the plant being only 3 feet in height, with a stem 24 inches in circum- ference. Endogenous or Monocotyledonous Stem. This kind of stem is composed of cells and vessels which are differently arranged from those of the Exogenous stem. The vascular bundles are scattered through the cellular tissue, and there is no dis- tinction between pith, wood, or bark. There are no medullary rays, nor concentric circles (fig. 129). . In the young state, the centre of the stem is occupied entirely by cells, which may be said to represent pith, and around this the vessels are seen, increasing in number towards the circumference. The central cellular mass has no medullary sheath. In some cases its cells are ruptured, and disappear during the progress of growth, leaving a hollow cavity (fig. 130); but in general it remains per- manent, and is gradually encroached upon by the development of the vascular system. The latter consists of vessels arranged in definite bundles, which do not increase by additions to. their outside after being once formed, although they are developed in @ progressive manner. (hime TE These bundles may be considered as representing \ " i | the vascular wedges, produced during the first mi Ip’ year of an exogenous stem’s growth (fig, 111). Fig. 130. They consist of woody vessels enclosing some cellular tissue between them, with spiral and pitted vessels, The outer part of the stem is not formed by a sepa- rable bark, but consists of a dense mass of fibrous tissue, mixed with laticiferous vessels and cells. It is intimately connected to the inner part of the stem, without the intervention of medullary rays. On making a transverse section of a young endogenous stem (fig. 131), there is observed a mass of cells or utricles, u, of various Fig. 129. Part of the stem of Asparagus cut transversely, showing the vessels as poiuts distributed through the cellular tissue. 1, Leaf in the form of ascale. Fig. 130. Trans- verse section of stem of Phragmites communis, or common reed. ‘The cellular tissue in the centre has disappeared, leaving a fistular or hollow stem, with a ring of cells and vessels, the latter indicated by dots. », Node where the fibres cross, so as to form a solid partition. ' ENDOGENOUS OR MONOCOTYLEDONOUS STEM. 65 sizes, often small in the vicinity of the vascular bundles, spiral vessels or trachex, ¢, large pitted vessels, v », laticiferous vessels, 2, and bast fibres, f, resembling those of liber, thickened by internal deposits. A similar section of a farther advanced endogenous stem, as of a Palm (fig. 132), shows numerous bundles of vessels dispersed irregularly in cellular tissue; those near the centre, m, being scattered at a distance from each other, while those towards the outside are densely aggregated, forming a darkish zone, 6, and are succeeded at the cir- cumference by a paler circle of less compact vessels, 2, with some com- pressed cells, covered by an epidermis, e, The peripherical portion, Ze, differs from true bark, in not being separable from the rest of the tissue. It has received the name of false bark, and consists of the epidermal TEE ine Fig. 131. Fig. 182. cells, e, and what has been called the cortical integument, 7. This portion of the stem is often very inconspicuous, but sometimes it is much developed, as in'Testudinaria elephantipes, in which it is rugged, and is formed of a sftbstance resembling cork in many respects. Mohl states that in the stem of a Palm there may be distin- guished a central region, a fibrous layer, and a cortical region; and the same divisions are pointed out by Henfrey in the stem of Spar- ganium ramosum and other monocotyledons. The central portion, representing the pith of dicotyledons, consists in Sparganium of spherical cells, containing starch, while the cortical or outer portion is formed by irregular cells, which are usually destitute of starch, It was at one time stipposed that the woody portion of these Fig. 131. Horizontal section of a vascular bundle from the stem of a Palm (Corypha frigida). t, Trachez, or spiral vessels. vp, Large pitted vessels, w, Cells or utricles of various kinds surrounding the vessels, and forming the parenchyma. 1, Laticiferous vessels. f, Fibres analogous to those of liber, thickened by concentric deposits. Fig. 132. Transverse section of part of the stem of a Palm (Astrocarywm Murumura). m, Central or medullary portion, in which the woody bundles are distant and scattered. b, External woody portion, where the fibres are numerous and densely aggregated, so as to form a dark zone. 1, Paler circle of more slender and less compact fibres, which may be considered as analogous to liber. ¢, Cellular epidermal portion. F 66 ENDOGENOUS OR MONOCOTYLEDONOUS STEM. stems was increased by additions to the centre, so that the first- formed fibres were gradually pushed towards the circumference by those which succeeded them, in the manner represented in Fig. 133, 1: hence the term Endogenous (260, within, and yevvcew, to pro- duce), meaning internal growth. : a But Mohl has shown that this is not strictly correct. For although the fibres connected with the leaves, in the first in- stance, are directed towards the centre, and are therefore always internal to those previously c formed, yet, when they are traced downwards, they are found not to continue in a parallel direc- tion, but to arch outwards, so as ultimately to reach the circum- ference. Hence, the newly-form- ed fibres really become external i at the base, although internal above. On making a vertical section of an endogenous stem, as of a Palm, there is observed an interlacing of fibres, similar to what is represented in Fig. 133, 2, where the four vascular bundles, abc d, are first direct- ed towards the centre, and then curve outwards towards the cir- cumference, so that those last formed ultimately become ex- ternal. The term Endogenous will, therefore, only apply strict- ly to the fibres at the early part of their course. Of late years, the terms Endogenous and Exo- genous have been discarded by many writers, the terms Mono- cotyledonous and Dicotyledonous being substituted. The true dis- tinction between Exogenous and Endogenous stems is, that in the former the woody or vascular bundles increase indefinitely at their 1 2 Fig. 133. Fig. 138. Diagrams illustrating the arrangement of four pairs of vascular bundles (a a, bb, cc, dd), in endogenous stems. 1, According to the old idea of internal development throughout the stem. 2. According to the view of Mohl, who has shown that the fibres interlace, and that those which are at first internal become external, lower down. ENDOGENOUS OR MONOCOTYLEDONOUS STEM. 67 periphery, while in the latter they are arrested in their transverse growth at a definite epoch. The investing bark of the former permits an unlimited extension of woody growth beneath it; the fibrous cor- tical layer of the latter, by maintaining an intimate union with the subjacent tissue, prevents unlimited increase in diameter. Hence we find that true endogenous stems do not attain the enormous diameter exhibited by some exogenous trees, such as Sequoia (Wellingtonia) gigantea and the Baobab,—the former of which has been measured 116 feet in circumference. The composition of the vascular bundles, in different parts of their course, varies, Thus, at the upper part, tracing them from the leaves towards the centre, they contain spiral vessels, pitted vessels with some cellular tissue, a few laticiferous vessels, and woody fibres resembling those of liber (fig. 131). As we descend, the spiral vessels disappear, then the pitted vessels; and when the bundles have reached the periphery, and have become incorporated with it, nothing but fibrous tissue, or pleurenchyma, remains, forming a complicated ana- stomosis or network. Thus, at the commencement, the bundles are large, but as they descend they usually become more and more atten- uated. In some instances, however, as in Ceroxylon Andicola, they increase at different parts of their course, probably by interstitial growth, and give rise to irregular swellings of the stem. This disten- sion takes place occasionally at the base of the stem, as in Euterpe montana. There are many herbaceous plants in this country, as Lilies, Grasses, etc., having endogenous stems, in which the course of the vascular bundles may occasionally be traced, but there are no British endogenous plants with permanent aerial woody stems. All the British trees are exogenous, Illustrations of endogenous stems must therefore be taken from trees of foreign countries, Palms furnish the best examples, In them the stem forms a cylinder of nearly uniform diameter throughout. The leaves are produced from a single terminal and central bud, called a Phyllophor or Phyllogen (pUAAoy, a leaf, and pogewv to bear, and yewdew, to produce). Connected with the leaves are the vascular bundles, and the bases of the leaves remain attached to the outer part of the stem, surrounded by the mattulla or reticulum. While the leaves produced by: one bud decay, another bud is de- veloped in the centre. As the definite vascular bundles are produced, the stem acquires increased thickness, but it is arrested in its trans- verse diameter at a certain epoch. The bundles, although developed progressively, do not multiply indefinitely; and thus a Palm-stem seldom becomes of great diameter. In consequence of this mode of formation, the outer part of a Palm-stem is the hardest and densest, and after acquiring a certain degree of firmness it resists all further distension, and frequently be- 68 ENDOGENOUS OR MONOCOTYLEDONOUS STEM. comes so hard as to withstand the blow of a hatchet. It has been already stated that in the exogenous stem provision is made for unlimited extension laterally, by the development of bundles of woody fibres and vessels indefinitely, and the formation of a separable bark which can be distended ; but in the endogenous stem there is no such provision. Hence, when the first formed or lowest part of the stem has increased to a certain amount, its progress is stopped by the hard indistensible outer fibrous covering ; and the same thing takes place successively in the higher parts of the stem, till at length all have ac- quired a comparatively uniform size, as is seen in the coco-nut palm (fig. 134, 1). In consequence of the small lateral increase of Palm- stems, a woody twining plant does less injury to them than to trees of exogenous growth. The growth of endogenous stems may be said to resemble an upward growth of an Exogen by terminal buds only, for there is no cambium layer, and no peripherical increase. In Palms, while the terminal shoot is developed, there are no an- nual rings. The hardening of the stem depends, in all pro- bability, partly on internal changes in the bast fibres, similar to what takes place in the heart-wood of Exogens, Occasionally, at the upper part of a palm-stem, there is an ap- pearance of zones, but it does not continue throughout the stem. From the absence of concentric circles, the age of a Palm cannot be estimated in the same way as that of an exo- genous tree. The elongation, however, of each species of Palm is pretty regular, and by it some idea may be formed Fig. 134. of its age. The rings on the stem do not usually indicate yearly growth. Fig. 134. Two endogenous or monocotyledonous trees, belonging to different fami- lies. 1. Cocos nucifera, or coco-nut, belonging to the Palm family. 2. Pandanus odora- tissimus, or screw-pine, belonging to Pandanacee. The first has a simple unbranched stem, with a cluster of leaves at the summit ; the second has a branched stem, with nume- rous leafy clusters, and peculiar aerial roots, proceeding from different parts of the stem. Two figures are given to indicate the height of the trees. ENDOGENOUS OR MONOCOTYLEDONOUS STEM. 69 In Palms, there is in general no provision for lateral buds, and no branches are formed. Hence, destroying the central bud will kill the tree. In some Palms, however, as the Doum palm of Egypt (Hy- phone thebaica), the stem divides in a forked or dichotomous (dinga, two ways, and réuve, to cut) manner. Gardner, in his travels in Brazil, noticed a Palm in which the central bud having been de- stroyed, two side ones had been produced, so as to give it a forked appearance. Other plants with endogenous stems also produce lateral buds. In fig. 134, 2, there is a representation of such a stem, in the case of the Screw-pine (Pandanus odoratissimus), and examples are seen in Grasses as the Bamboo, in Asparagus, Cordyline, and Dracena. In these cases the stem is more or less tapering, like that of Exogens, and the destruction of the terminal bud is not neces- sarily followed by the death of the plant. The development of lateral buds is often accompanied by an increased diameter of the stem. ‘The famous Draceena Draco, or Dragon tree of Orotava, in the Canary Islands, had a hollow stem capable of holding several men; and the fact of its living in this state is marked by Jussieu as an argument against the strict endogenous formation ; for, if the centre were the youngest and newest part, its destruction would put an end to the existence of the tree in the same way as the removal of the outer part of the wood would destroy an exogenous stem. Professor Piazzi Smyth remarked that this famous Dragon tree was covered on the out- side with root-like fibres, which descended from the branches to the ground. The tree is now destroyed. The branches in such plants are formed on the same principle as the stems; but their fibres do not proceed to the centre of the stem, but extend outside the pre-existing bundles, between them and the outer false bark (fig. 132, 2 e), and thus give rise to lateral increase. In Grasses, the stem or culm is usually hollow or fistular (fig. 130), in consequence of the outer part, by its rapid increase, causing the rupture and ultimate disappearance of the internal cellular portion. The fibres in some Grasses cross from one side to the other, forming partitions, as in Bamboo, which add much to the strength of the stem. When the internodes of the caudex of a Palm are not much elongated, the scars of the leaves are seen forming spirals on the stem, as in the coco-nut and date. In Xanthorrhcea Hastile the same arrangement is observed. In Palms, such as species of Chameedorea, the internodes are much lengthened, and rings are seen on the stem at distant intervals, showing thickened node-like joints. Some Palm stems, as those of Calamus Rudentum, the common cane, are very thin and slender. In many Endogenous or Monocotyledonous plants the stem remains below ground, developing shoots which are simple, as in Banana and Plantain, or branched, as in Asparagus, In the former, the stem above ground is an herbaceous shoot, composed 70 ACROGENOUS OR ACOTYLEDONOUS STEM. of the sheaths of the leaves. It dies after fruiting, and is succeeded by other shoots from the subterranean stem. The shoots or buds from such stems occasionally remain in part below ground in the form of bulbs, as in Lilies, Tulips, and Hyacinths; or as corms, in Col- chicum, Crocus, Gladiolus, and Arum. Tn some instances the aerial stem has the usual endogenous struc- ture, while in the underground stem the vascular bundles are in the form of wedges, with cellular tissue in the centre, thus resembling Exogens. This structure has been remarked in the Smilax or Sarsa- parilla family. Lindley calls these plants Dictyogens (dixrvov, a net), from their netted leaves, by which they differ from most Endogens. Henfrey holds that the ring of woody fibres in these plants, as seen in Tamus and Smilax, is an alteration of the parenchymatous cells of the periphery, and is not produced in the same way as the zones of Dicotyledons. He considers this ring as probably analogous to the liber, and not to the indefinite vascular bundles of Exogenous stems. Acrogenous or Acotyledonous Stem. This stem, in its general external aspect, resembles that of Endogens. It is unbranched, usually of small, nearly uniform diameter, and produces leaves (fronds) at its summit. It is easily distinguished by its internal structure. Tree Ferns furnish the best example of this kind of stem. In them it is denominated a Stipe, and it often attains the height of 120 feet (fig. 135). A transverse section of the stem (fig. 136) exhibits an irregular circle of vascular bundles, composed of masses, z J, of various forms and sizes, situated near the circumference ; the centre, m, being formed of cellular tissue, and often becoming hollow. On the outside of the vascular circle, cells exist, p, covered by an epidermal layer or cellular integument, ¢, often of hard and dense consistence, and marked with the scars of the fronds. The vascular bundles are formed simultaneously, and not pro- gressively, as in the stems already noticed; and additions are made in an upward direction, The stem is formed by additions to the summit, and by the elongation of vessels already formed ; hence the name Acrogenous (éxgos, summit). The plants are also called Acrobrya (déxeos, summit, and Pete to germinate). The vascular system is of greater density than the rest of the tissue, and is usually distinguished by the dark colour of the pleurenchyma or prosenchyma (fig. 136 f), which surrounds the paler vessels in the centre (fig. 136 v v). There is a continuous woody cylinder in the Fern stem. The vascular bundles, however, do not follow a straight course, but unite and separate, leaving spaces between them, similar ACROGENOUS OR ACOTYLEDONOUS STEM. 71 to the meshes seen in the liber of Exogens (fig. 119). In these spaces vessels of communication pass between the outer or cortical, and the inner or central portions of the stem. From the point where the vascular bundles unite or anastomose, other vessels are given off to supply the fronds, and some pass into the ad- ventitious roots, which are often pro- duced abundantly on the outside of the stipe (fig. 135 ra). The trunk of the Acrogen differs from that of the Exogen, by having its Fig. 136. a vascular cylinder penetrated by only bh one kind of horizontal tissue, namely, EN the vascular bundles belonging to the fronds ; while the Exogen has in addi- tion another horizontal tissue, namely, ‘medullary rays, composed of cellular tissue, and performing a totally different function. The acrogenous stem in the young state is solid, but it frequently be- comes hollow in the progress of, growth, by the rupture and absorp- Fig. 135. Tree fern (Alsophila perrotetiana), of the East Indies. Stem or stipe is cylindrical, unbranched, and presents at its base, r a, a conical enlargement, formed by a mass of adventitious roots. The leaves are terminal, and in the young state are rolled up in a circinate manner. Fig. 186. Transverse section of the stem of a Tree fern (Cyathea). m, Cellular tissue, corresponding to pith, occupying the central part. 21, Vascular circle composed of numerous irregularly-formed masses. jf, Dark-coloured woody or prosenchy- matous fibres, forming the borders of the vascular masses. vv, Pale-coloured vessels, chiefly scalariform, occupying the centre of the masses. p, Parenchymatous or cellular external zone, communicating with the central portion, e, Hard epidermal envelope, occupying the place of the bark. 72 ACROGENOUS OR ACOTYLEDONOUS STEM. tion of the walls of the cells in the centre. The bases of the leaves remain long attached, but ultimately fall off, leaving marked scars which are at first close together, but often separate afterwards by interstitial growth. On these scars or evcatrices (cicatriz, a wound) the markings of the vessels are easily seen, arranged in the same manner as those of the stem, with which they are continuous. The vascular system of ferns consists chiefly of scalariform vessels (fig. 64), mixed with annular (fig. 62), woody and pitted vessels (fig. 116 ter). There are no true tracheze with fibres which can be unrolled. In the stems of Lycopodiacee closed tracheze or ducts occur; and in Kqui- setacez the rings of the annular vessels are closely united. The stem of Ferns is generally of small diameter; it does not increase much laterally, after having been once formed, and it does not produce lateral buds. Sometimes it divides into two (fig. 137), by the formation of two buds at its growing point. This, however, is an actual division of the stem itself, and differs from the usual branching of Exogenous and Endogenous stems, In the Ferns of this country the stems usually creep along and under the ground, and the leaves which they produce die annually, with- out giving origin to a conspicuous trunk. In the common Brake (Preris aquilina), the arrange- ment of the vascular system may be seen by making a transverse section of the underground stem. The plant has received its name aquilina, from a supposed resemblance to a spread eagle, presented by the vessels when thus cut across. The axis of Lycopodiaceze or Club-mosses (fig. 138) exhibits a vascular bundle of scalariform vessels and closed spirals. The bundle is developed in an upward direction as the stem grows, each inter- node having its permanent bundle. Vessels pass from the stem to the leaves. In Equiseta or Horse-tails (fig. 139) there is a circle of vascular bundles towards the exterior of the aerial stem; this vascular ring is covered by cortical cells of different kinds. The Equiseta have underground stems, from which the aerial branches are sent up annually. In some species the aerial stem attains a height of upwards of 30 feet. The largest species in Britain (Equisetum maximum), may be seen 5 to 6 feet high, with a diameter of half- an-inch. The aerial stem of the plant consists of hollow internodes, each with a transverse diaphragm at the base, and a sheath at the Fig. 187. Fig. 137. Vertical section of part of the forked stem or stipe of Alsophila perrotetiana. m, Cellular central portion. 21,21, Vascular zone, consisting chiefly of woody fibres and scalariform vessels. The forking is caused by an actual division of the stipe. ACROGENOUS OR ACOTYLEDONOUS STEM. 73 upper end. The sheath of the lower internode embraces the base of the internode above it (fig. 139). The vascular bundles unite to form a hollow cylinder im the stem. In fig. 140 is shown the structure of a vascular bundle of Equisetum hyemale, with a hollow cavity or lacuna, 2, round which are large annular and spiral vessels, J v, smaller vessels, s v, and peculiar cells, ¢ v; which, Fig. 138. Lycopodium clavatwm, a species of Club-moss, showing a branch, J, covered with minute pointed leaves, from which proceeds a stalk bearing at its extremity two spikes, f, consisting of modified leaves with fructification. Fig, 139. Fructification of a species of Horse-tail (Equisetwm maximum). The stalk is surrounded by a series of membranous sheaths, ss, which are fringed by numerous sharp processes or teeth. The fructification, J, is at the extremity of the shoot, in the form of a pyramidal mass of polygonal scales, ‘bearing spores on their under surface. The fructification in some species is on the same branch with the leaves, while in others it is on a separate branch. 74 ACROGENOUS OR ACOTYLEDONOUS STEM. by their union, and the partial absorption of their transverse walls, form what are called cribriform or sieve-like vessels (vasa propria), thickened bast cells (6 p), and bast fibres (0 f). Fig. 140. In some Thallogens the thallus or frond is supported by a stalk, in which there are concentric parenchymatous circles, with divisions in the form of rays, but no vascular bundles. These appearances are presented by some large antarctic seaweeds (species of D’Urvillea and Lessonia), and by some lichens, as Usnea. Fig. 140. Section of vascular bundle of stem of Equisetum hyemale x 310. Lacuna ora cavity, 1; parenchyma, a form of starch cells, p p ; large vessels, J v ; small vessels, s v; bast cells, 6 p; and bast fibres, b f; cribriform vessels, c v, formed by united cells, with a partial absorption of their transverse walls.—Trans. Bot. Soc. Edin. DEVELOPMENT AND FUNCTIONS OF STEM. 75 There are thus three kinds of stems in the vegetable kingdom, which may be defined generally as follows :— 1. Exogenous or Dicotyledonous, having a separable bark ; distinct concentric circles, composed of progressive indefinite vascular bundles, increasing at their periphery, the density diminishing from the centre towards the circumference ; pith enclosed in a longitudinal canal or medullary sheath, with cellular prolongations in the form of medullary’ rays. : 2. Endogenous or Monocotyledonous, having no separable bark ; no distinct concentric circles ; vascular bundles progressive and definite, not increasing at their periphery, the density diminishing from the circumference to the centre; no distinct pith, no medullary sheath nor medullary rays, the cellular tissue being interposed between the vascular bundles. / 3. Acrogenous or Acotyledonous, having no separable bark ; no con- centric circles; vascular bundles simultaneous, forming an irregular ‘circle ; additions being made to the summit; no distinct pith, no medullary sheath nor medullary rays ; conspicuous scars left by the bases of the leaves, stem in some cases entirely cellular. Formation of the different parts of Stems, and their special Functions. The stem produces the buds from which branches, leaves, and flowers are developed ; it exposes these organs to the atmosphere and light, conveys fluids and air, and receives secretions. Stems vary much in their size, both as regards height and diameter. Some oaks in Britain have a height of nearly 120 feet ; forest trees in France have attained to 120 and 130 feet, and in America even to 450 feet. Some Palms attain a height of 200 feet. The trunks of the Baobab and Welling-. tonia are sometimes 30 or 40 feet in diameter. The pith, in its early state (fig. 111 p), is of a greenish colour, and contains much fluid, which is employed in the nourishment of the young plant. After serving a temporary nutritive purpose it becomes dry, or disappears by rupture and absorption of the walls of the cells which enter into its composition. The medullary sheath, which is the first formed vascular layer (fig. 113 em), keeps up a connection between the central parts of the stem and the leaves, by means of spiral vessels, which seem to be concerned partly in the conveyance of air. This is the part of a Dicotyledonous stem in which these vessels ordinarily occur. The medullary rays (fig. 114 7m) preserve a com- munication between the bark and the pith. The cells of which they are composed are concerned in the production of leaf-buds, and they assist in the elaboration and conveyance of secretions. They have a direct connection with the cambium cells (fig. 114 ¢), or the cells be- tween the wood and bark, whose function is to aid in the formation of 76 FORMATION OF WOOD. new wood. The bark (fig. 114 fc, e¢, p) protects the tender wood, conveys the elaborated sap downwards from the leaves, and is the part in which many valuable products, such as gum, tannin, and bitter principles, are formed and deposited. The vascular bundles (fig. 114 fl, vp) convey the sap from the root to the leaves. This function is carried on during the life of the plant by the annular vessels and ‘the pitted vessels, as well as other kinds of fibro-vascular tissue ; but in the fibres of the wood it ceases at a certain epoch, in consequence of the tubes being filled up by secondary deposits, so as to form the perfect wood, which gives strength and stability to the stem. Considerable differences of opinion have arisen on the subject of the formation of wood. All agree that it cannot be properly formed unless the leaves are exposed to air and light, but physiologists differ as to its mode of formation. Some say that it is produced in a hori- zontal, others in a vertical direction. There seems to be no doubt that the cambium cells perform an important part in the formation of wood, and that their activity depends on the proper development of leaves. These formative cells, although most easily detected in exo- genous stems, are also present in the other forms of stems which have been described. In Monocotyledonous stems these cambium cells are situated in the centre of the bundles, and are concerned in the forma- tion of the vascular tissue surrounding them. In woody Acotyle- , donous stems, as in Tree-ferns, these cells surround the vascular bundles. After a certain time the cambium zones in these stems be- come ligneous, and then the vascular bundles only grow at their ex- tremity by means of unchanged cambium cells. In both these kinds of stems the vascular bundles are limited, and the stems can only increase laterally by ramifying or dividing dichotomously (fig. 137). Knight espoused what is called the vertical theory, considering the wood as developed in a downward direction by the leaves, and in this view he was supported by Petit-Thouars and Gaudichaud. These phy- siologists maintain that there are two vascular systems in plants, an ascending and descending; the one connected with the leaf-forma- tion, or the spiral vessels ; the other connected with the production of roots, or the ligneous fibres ; the cellular tissue being more especi- ally concerned in horizontal development. Every bud is thus, accord- ing to them, an embryo plant fixed on the stem, sending leaves upwards, and roots downwards. The dicotyledonous embryo was supposed to be formed by two phytons (guréy, a plant) united, having each an ascending and descending system of vessels, while the monoco- tyledonous embryo was composed of one such phyton. In Palms, Dracznas, and other Endogenous stems, the peculiar manner in which the fibres interlace (fig. 133, 2) favours the opinion that they are developed like roots, by additions to their extremities ; and this is also strengthened by the formation of adventitious or aerial roots, FORMATION OF WOOD. 77 which burst through different parts of the stem in Palms, Screw- pines (fig. 134, 2), the Banyan, and in the Fig tribe generally. In Vellozias and Tree Ferns, the surface of the stem is often covered with thin roots, protruding at various parts, and becoming so incor- porated with the stem as to appear to be a part of it. In the Tree- Fern, represented in fig. 135, the lower part of the stem is enlarged in a remarkable degree by these fibres, so as to give it a conical form. In exogenous stems, when ligatures are put round the stem, and when portions of bark are removed, a swelling takes place above the parts where the injury has been inflicted, thus apparently proving that the new matter is developed from above downwards, Gaudichand endeavours to account for various anomalous forms of stems (figs. 123-126), by considering them as depending on the arrangement of the leaves, and on the mode in which the woody fibres are sent down from them. Thus, the four secondary masses surrounding the central one in the stem of Calycanthus floridus are traced to four vascular bundles from the leaves, penetrating the cellu- lar tissue of the bark, distinct from the central wood and from each other, except at the nodes, where the cross bundles unite them so as to form a ring round the central mass. New fibres are formed on the inner side of these bundles, and by degrees they assume a crescentic shape, while the horns of the crescent ultimately unite on the outer side (centrifugally), and enclose a portion of the bark, which thus forms a kind of spurious excentric pith, with numerous woody layers on the inside, and a smaller number on the outside. Again, in Brazilian Sapindace (fig. 124), with five, seven, nine, or ten woody masses, the same thing is said to occur, with this difference, that the pith of each of the masses is derived from the original medullary centre, por- tions of which are enclosed by the vascular bundles in a centripetal manner, or from without, inwards. Treviranus states that the fibrous and vascular bundles descending from the leaves are destined in general to unite around a common centre, but that they retain a certain degree of independence, and may be developed separately in some instances, giving rise to ano- malous fasciculated stems. Gardner, from an examination of Brazilian Palms, adopts the vertical theory. It is, however, opposed by most vegetable physio- logists, who consider the development of the vascular bundles as proceeding from below upwards; in Dicotyledons, by peripherical production of woody and vascular tissue from cambium cells ; and in Monocotyledons, by a definite formation of woody and vascular bundles by means of terminal buds ; the hardening of the stem de- pending on the interstitial changes which take place afterwards in the woody fibres. , All physiologists agree in believing that the formation of woody 78 FORMATION OF WOOD. matter depends mainly on the functions of the leaves being car- ried on properly, and this can only be effected by exposure to. air and light. The more vigorously the plant grows, the better is the wood produced. Experiments made in the British dockyards proved that those oaks which had formed the thickest zones yielded the best timber. Barlow’s experiments at Woolwich showed that a plank of quick-grown oak withstood a greater strain than a similar plank of slow-grown oak, The stumps of fir-trees sometimes exhibit a circle of woody tissue which has been formed after the trees have been cut down, and without the agency of leaves. In some cases the vigour of these stumps has been traced to the roots being grafted into those of adjoining trees bearing branches and leaves. In order that trees may grow well, and that timber may be pro- perly formed, great care should be taken in planting at proper dis- tances, and in soil fitted for the trees. Firs ought to be planted from 6 to 8 feet apart ; and hardwood trees, for a permanent plantation, 28 feet distant, the spaces being filled up with larch, spruce, or Scotch fir, according to soil and situation. Hardwood is of no value till it has attained some age, while larch and spruce may be applied to use in ten or twelve years ; and thus judicious thinning may be practised. When trees are set too close their leaves are interrupted in their functions ; many of them fall off, leaving the stems bare ; the wood is imperfectly formed, and the roots are not sent out vigorously. When such plantations are allowed to grow without being thinned, the trees are drawn up without having a hold of the ground ; and when some of them are subsequently removed the remainder are easily blown over by the wind. In thick plantations it is only in the trees next the outside, where the leaves and branches are freely formed, that the wood and roots are properly developed. When a tree is fully exposed to air and light on one side only, it is frequently found that the woody zones on that side are largest. When trees are judiciously planted, there is a great saving both in the original outlay and in the subsequent treatment. Pruning, or the shortening of branches, and the removal of superfluous ones, ought to be cautiously practised. It is only applicable to young branches and twigs ; and is had recourse to chiefly in the case of fruit-trees, when the object is to make the plants produce flowers and fruit. If forest trees are pro- perly planted and thinned, little pruning is required. STRUCTURE OF LEAVES. 79 LEAVES AND THEIR APPENDAGES. Structure of Leaves. Leaves are expansions of the bark, developed in a symmetrical manner, as ‘lateral appendages of the stem, and having a connection with the internal part of the ascending axis. They appear at first as small projections of cellular tissue, continuous with the bark, and ‘closely applied to each other. The points from which they arise are called nodes. In the early stages of their development they are undivided. The cellular papillee, from which they originate, gradually expand in various ways, acquire vascular tissue, and ultimately assume _. their permanent form and position on the axis. They may be divided into aerial and submerged leaves, the former being produced in the air, and the latter under water. Ariat Leaves.—These leaves consist of vascular tissue in the form of veins, ribs, or nerves, of cellular tissue or parenchyma filling up the interstices between the veins, and of an epidermal covering. The Vascunar Sysrem of the leaf is continuous with that of the stem, those vessels which occupy the internal part of the stem becoming superior in the leaf, while the more ex- ternal become inferior. Thus, in the upper part of the leaf, which may re- present the woody layers, there are spiral vessels (fig. 141 ¢), annular, reticulated, and pitted vessels, v, and ligneous fibres, Ff; whilst in the lower side, which may re- present the bark, there are laticiferous vessels and fibres, resembling’ those of liber, 2. There are usually two layers of fibro-vascular tissue in the leaf, which may be separated by maceration, They ¥ may be seen in what are called skeleton leaves, in which the cellular part is re- moved, and the fibro-vascular tissue is left. The vascular system of the leaf is distributed through the cellular tissue Fig, 141. in the form of simple or branching veins. The Eprpermis (fig. 142 ¢ s,e¢ +), composed of cells more or less compressed, has usually a different structure and aspect on the two Fig. 141. Bundle of fibro-vascular tissue, passing from a branch, }, into a petiole, ». The vessels are first vertical, then nearly horizontal, but they continue to retain their telative position, Changes take place in the size of the cells at the articulation a. tt, Traches or spiral vessels in which the fibre can be unrolled. vv, Annular vessels. f/f, Fibres of wood. 11, Cortical fibres, or fibres of liber, or the inner bark. 80 STRUCTURE OF LEAVES. surfaces of the leaf. It is chiefly on the epidermis of the lower sur- face (fig. 143 ¢ +), that stomata, ss, are produced, occupying spaces between the veins, and it is there also that hairs usually occur. In these respects the lower epidermis resembles the outer bark of young stems, with which it may be said to correspond. The lower epidermis is often of a dull or pale-green colour, soft, and easily detached. The Sern rs Fig. 143. shining, and sometimes becomes very hard and dense. Many tropical plants present on the upper surface of their leaves several layers of compressed epidermal cells. These appear to be essential for the pre- servation of moisture in the leaf. In leaves which float upon the sur- face of water, as those of the water-lily, the upper epidermis alone possesses stomata (p. 30). On removing a strip of epidermis, part of the parietes of the cells below is often detached in the form of a green net- work (fig. 144 pp), and on examina tion under the microscope, the stomata, 8 Ss, are seen communicating with colourless spaces, / J 1, surrounded by green matter. The ParmncHyma of the leaf is the cellular tissue surrounding the Fig. 144. vessels, and enclosed within the epi- dermis (fig..142 ps, pw.) It has sometimes received the names of Diachyma (sé, in the midst, and xin, tissue), or Mesophyllum (uéoos, middle, and plA?.ov, a leaf), or Diploé (didn, a fold). It is formed of two distinct series of cells, each containing chlorophyll or green-coloured granules, but Fig. 142. Thin vertical section of the leaf of a Lily, highly magnified. es, Epidermis of upper pagina or surface. ei, Epidermis of lower surface. ps, Parenchyma of upper por- tion of the leaf, composed of close vertically-placed cells. pi, Parenchyma of lower portion, composed of loose horizontal cells, m, Intercellular passages. 11, Lacune. Fig. 143. Similar section of the leaf of Balsam. The letters denote the same parts as in fig. 142. ss, stomata. Fig. 144. Strip of the lower epidermis, ¢ ¢, of the leaf of Balsam, showing a network formed by a portion of the parenchyma below, p p, being detached. The spaees of the net are lacune, 711, often corresponding to stomata, ss. STRUCTURE OF LEAVES. 81 differing in form and arrangement. This may be seen on making a ver- tical section of a leaf, as in figs. 142 and 143. Below the epidermis of the upper side of the leaf there are one or two layers of oblong blunt cells, placed perpendicularly to the surface (fig. 142 s), and applied so closely to each other as to leave only small intercellular’ spaces (fig. 142 m), except when stomata happen to be present. On the under side of the leaf the cells are irregular, often branched, and are arranged more or less horizontally (fig. 142 p <), leaving cavities between them, 11, which often communicate with stomata (fig. 143 ss). On this account the tissue has received the name of cavernous. The form and arrangement of the cells, however, depend much on the nature of the plant, and its exposure to light and air. Sometimes the arrangement of the cells on both sides of the leaf is similar, as occurs in leaves which have their edges presented to the sky. In very succulent plants the cells form a compact mass, and those in the centre are often colourless. In some cases the cellular tissue is deficient at certain points, giving rise to distinct holes in the leaf, as in Monstera Adan- sonii; such a leaf has been called pertuse (pertusus, bored through), In Victoria regia perforations in the leaf seem to be subservient to the purposes of nutrition, in permitting the gases collected beneath the large expanded leaf to escape, and thus allowing its under surface to be brought into immediate contact with the water. ‘ SuBMERGED Lzaves.—Leaves which are developed under water differ in structure from aerial leaves. They have usually no fibro- ait PR E SEEGER eS EED a ae eo en <<] FER Be ae ‘i SS EELS EES NCGS i oe Fig, 145. Fig. 146. vascular system, but consist of a congeries of cells, which sometimes become elongated and compressed so as to resemble veins. They have a layer of compact cells on their surface (fig. 145 p), but no true epidermis, and no stomata, Their internal structure consists of cells, disposed irregularly, and sometimes leaving spaces which are filled with air for the purpose of floating the leaf (fig. 145 7), When exposed to the air these leaves easily part with their moisture, and become shrivelled and dry. In the submerged leaves of Trapa and Fig. 145. Perpendicular section through a small portion of the submerged leaf of Pota- mogeton perfoliatus. p, Parenchyma. J, Lacune. Fig. 146, Fenestrate leaf composed of filamentous cells, with intervening spaces, G 1 82 STRUCTURE OF LEAVES. Callitriche, spiral vessels have been seen. In some instances there is only a network of filamentous-like cells formed (fig. 146), the spaces between which are not filled with parenchyma, giving a peculiar skeleton appearance to the leaf, as in Ouvirandra fenestralis (lat- tice plant). Such a leaf has been called fenestrate (fenestra, a window). A leaf, whether aerial or submerged, generally consists of a flat expanded portion (fig. 147 1), called the blade, limb, or lamina, of a narrower portion called the petiole (petiolus, a little foot or stalk) or stalk (fig. 147 p), and sometimes of a portion at the base of the petiole, which forms a sheath or vagina ( (fig. 147 g), or is developed in the form of leaflets, called stipules (fig. 205). The sheathing portion is sometimes in- corporated with the stem, and has been called tigellary (tige, Fr., a stem or stalk) by Gaudichaud. These portions are not always present. The sheath- ing or stipulary portion is frequently wanting, and occasionally only one of the other two is developed. When a leaf has a distinct stalk it is called petiolate ; when it has none, it is sessile (sessilis, from sedeo, I sit). When sessile leaves embrace the stem, they are called amplemcaul (amplexor, I embrace, and caulis, a stem). The part of the leaf next the petiole or the axis is the base, while the opposite extremity is the apex, The surfaces of the leaf are called the paginw (pagina, a flat page), and its edges or margins form the circumscription of the leaf. The leaf is usually horizontal, so that the upper pagina is directed towards the heavens, and the lower pagina towards the earth. In some cases leaves, or leaflike petioles, are placed vertically, as in Australian Acacias, Eucalypti, etc. In other instances, as in Alstrémeria, the leaf be- comes twisted in its course, so that what is superior at one part becomes inferior at another. The upper angle formed between the leaf and the stem is called its avil (a«illa, armpit), and everything arising at that point is called avillary. It is there that leaf-buds (p. 108) are usually developed. The leaf is sometimes articulated with the stem, and when it falls off a scar or cicatricula remains; at other times it is continuous with it, and then decays gradually, while still attached to the axis. In their early state all leaves are continuous with the stem, and it is only in their after growth that articulations are formed. When leaves fall Fig. 147. Fig. 147. Leaf of Polygonum Hydropiper, with a portion of the stem bearing it. 1, Limb, lamina, or blade. p, Petiole or leaf-stalk. g, Sheath or vagina, embracing the stem, and terminated by a fringe, f. STRUCTURE OF LEAVES. 83 off annually, they are called deciduous ; when they remain for two or more years, they are evergreen, The laminar portion of a leaf is occasionally articulated with the petiole, as in the Orange (fig. 201), and a joint at times exists between the v4ginal or stipulary portion’ and the petiole, Distribution of the Veins, or Venation of Leaves, The distribution of the veins has been called Venation, sometimes Nervation, In most leaves this can be easily traced, but in the case of succulent plants, as Hoya, Agave, Stonecrop, and Mesembryanthemum, the veins are obscure, and the leaves are said to be Hidden-veined (figs. 186, 187). In the fronds of the lower tribes of plants, as seaweeds, and in submerged leaves, there are no true veins, but only condensations of elongated cellular tissue, and the term Veinless (avenia) is applied. In an ordinary leaf, as that of Lilac or Chestnut, there is observed a central vein larger than the rest, called the midrib (fig. 148 nm); this gives off veins laterally (primary veins) ns ns ns, which either end in a i Fig. 148. Fig. 149, Fig. 150. curvature within the margin, as in Lilac and Belladonna (fig. 148), or go directly to the edge of the leaf, as in Oak (fig. 149) and Chestnut. If they are curved, then external veins and marginal veinlets are inter- Fig. 148. Leaf of Belladonna. p, Petiole or leaf-stalk. mm, Midrib. ns ns ns, Primary veins, ending in curvatures at their extremities. Fig. 149. Leaf of Oak, pinnatifid or divided into lateral lobes ; feather-veined, the veins going directly to the margin. ’ Fig. 150. Leaf of Banana (Musa), showing the midrib, with the primary veins running parallel to each other in a transverse manner, and proceeding to the margin. No reticulation. Plant monocotyledonous. 84. STRUCTURE OF LEAVES. spersed through the parenchyma external to the curvature. There are also other veins of less extent (costal veins) given off by the midrib, and these give origin to small veiniets. In some cases, as Sycamore and Cinnamon, in place of there being only a single central rib, there are several which diverge from the part where the blade joins the petiole or stem. Thus, the primary veins give off secondary veins, and these in their turn give off tertiary veins, and so on, until a com- plete network of vessels is produced. To such a distribution of veins the name of Reticulated or Netted venation has been applied. In the leaves of some plants there exists a central rib or midrib, with veins running nearly parallel to it from the base to the apex of the leaf, as in grasses (fig. 210); or with veins diverging in more or less parallel lines, as in Fan Palms; or with veins coming off from it throughout its whole course, and running parallel to each other in a straight or curved direction towards the margin of the leaf, as in Plan- tain and Banana (fig. 150). In these cases the veins are often united by cross veinlets, which do not, however, form. an angular network, These are called Parallel-veined, Leaves may thus be divided into two great classes, according to their venation—Reticulated or netted-veined leaves, in which there is an angular network of vessels, as seen generally in dicotyledonous plants ; and Parallel-veined leaves, in which the vessels run in a straight or curved manner from base to apex, or from the midrib to the margin of the leaf, and in which, if there is a union, it is effected by transverse veins which do not form an angular network. This kind of leaf occurs commonly in monocotyledonous plants. In many acotyledonous plants there is no true vascular venation, but when it is present, there is frequently a tendency in the veins to divide in a forked (furcate) manner. This is seen in many Ferns, which have hence been called Fork-veined, Condensed cellular tissue forming false venation is seen in mosses and in seaweeds. TABULAR ARRANGEMENT OF VENATION. A.—Reticulated Venation. I. Unicostate (wnus, one). A single rib or costa in the middle (midrib). 1. Primary veins coming off at different points of the midrib. w. Veins ending in curvatures within the margin (fig. 148), and forming what have been called true netted leaves (Lilac’). 4, Veins going directly to the margin (fig. 149), and forming feather-veined leaves (Oak and Chestnut). 2. Primary veins coming off along with the midrib (fig. 158) from the base of the leaf. Il. Multicostate (multus, many). More than one rib. In such cases there are frequently three (tricostate), as in fig. 177, or five (quinquecostate), as in fig. 173. Authors usually give to these leaves the general name of costate or ribbed. 1. Convergent, Ribs converging, running from base to apex in a curved FORMS OF SIMPLE LEAVES. 85 manner, as in Cinnamon and Melastoma (fig. 173). There is occa- sionally an obscure rib running close to the edge of the leaf, and called intramarginal, as in the Myrtle. 2. Divergent. Ribs diverging or proceeding in a radiating manner (fig. 159). This is called radiating venation, and is seen in Sycamore, Vine, Geranium, Castor-oil plant (fig. 161). B.—Parallel Venation.—The term parallel is not strictly applicable, for the veins often proceed in a radiating manner, but it is difficult to find a comprehensive term. This venation may be characterised as not reticulated. I, Veins proceeding transversely from midrib to margin, usually with convexity towards the midrib, as in Musa (fig. 150) and Canna, II. Veins proceeding longitudinally from base to apex. 1. Veins more or less convergent (fig. 188), as in Iris, Lilies, Grasses (fig. 210). 2. Veins more or less divergent, as in Fan Palms. C.—Furcate Venation (furca, a fork). Veins dividing in a forked manner, as in the case of many Ferns. Forms of Leaves, Leaves are divided into simple and compound. The former have no articulation beyond the point of their insertion on the stem or Fig. 151. Fig. 152. Fig. 153. branch, and consist of a single blade, which, however, may be vari- ously divided (figs. 151, 152, 153, etc.) The latter have one or more articulations beyond the point of their insertion on the stem, and con- Fig. 151. Leaf of Ulmus effusa. Reticulated venation ; primary veins going to the margin, which is serrated. Leaf unequalatthe base. Fig. 152. Pinnatifid leaf of Valeriana dioica. Fig. 153. Bipinnatifid leaf of Papaver Argemone. Feather-veined. 86 FORMS OF SIMPLE LEAVES. sist of one or more leaflets (foliola) separately attached to the petiole or leaf-stalk (fig. 156). In a single leaf the blade may be either’ attached to a petiole or sessile on the stem ; while in a compound leaf the blades or leaflets are separately attached to the petiole. In the earliest stage of growth all leaves are simple and undivided, and it is only during the subsequent development that divisions appear, which may commence at the base or at the apex of the leaf. The forms which the different kinds of simple and compound leaves assume are traced to the character of the venation, and to the amount of parenchyma produced. SrmmpLrE Leaves.—When the parenchyma is developed symme- trically on each side of the midrib or stalk, the leaf is equal (fig. 164); if otherwise, the leaf is wnequal or oblique (fig. 151), as in Begonia, If the margins are even and present no divisions, the leaf is entire (i- teger), as in figs, 164 and 165; if there are slight projections of cellular or vascular tissue beyond the margin the leaf is not entire (fig. 151); when the projections are irregular and more or less pointed, the leaf is dentate or toothed (fig. 170); when they lie regularly over each Fig. 154. Fig. 155. Fig. 156, Fig. 157. Fig. 158. Fig, 159. other, like the teeth of a saw, the leaf is serrate (figs. 151, 169); when they are rounded, the leaf is crenate (fig. 174). If the divisions extend more deeply than the margin, the leaf receives different names accord- ing to the nature of the segments: thus, when the divisions extend about half-way down (figs. 149, 159), it is cleft (fissws), and its lines of separation are called fissures (fissura, a cleft); when the divisions extend nearly to the base or to the midrib (fig. 185), the leaf is partite, and its lines of separation are called partitions, These divisions take place in simple leaves exhibiting different kinds of venation, and give rise to marked forms, Thus, if they occur in a feather-veined leaf (fig. 152), it becomes either pinnatifid (pina, a wing or leaflet, and jissus, cleft), when the segments extend Fig 154. Lyrate leaf of Barbarea. Fig. 155. Panduriform, a fiddle-shaped leaf of Rumex pulcher. Fig. 156. Compound leaf, ternate, the leaflets being obcordate, Fig. 157. Compound leaf; quaternate, the leaflets being rotundate-cuneiform, or wedge- shaped with rounded apices. Fig. 158. Two-lobed leaf, somewhat cordate at the base, emarginate, and mucronate. Fig. 159. Palmate leaf, the divisions acute and serrated at their margins, Radiating venation. FORMS OF SIMPLE LEAVES. 87 to about the middle and are broad ; or pectinate (pecten, a comb), when they are narrow ; or pinnatipartite, when the divisions extend nearly to the midrib, ‘These primary divisions may be again subdivided in a similar manner, and thus a feather-veined leaf will become bipinnatifid (fig. 153), or bipinnatipartite ; and still further subdivisions give origin to tripinnatifid and laciniated leaves. If the divisions of a pinnatifid leaf are more or less triangular, and are pointed downwards towards the base, the extremity of the leaf being undivided and triangular, the leaf is runcinate (runcina, a large saw), as in the Dandelion. When the apex consists of a large rounded lobe, and the divisions, which are also more or less rounded, become gradually smaller towards the base (fig. 154), as in Barbarea, ‘the leaf is called lyrate, from its resemblance to an ancient lyre. Under the term lyrate some include compound pinnate leaves in which the several pinnz are united at the apex of the leaf, and the others become gradually smaller towards the base. When there is a concavity on each side of a leaf, so as to make it resemble a violin, as in Rumex pulcher (fig. 155), it is called panduri- form (ravdotgn, a fiddle). The same kinds of divisions taking place in a simple leaf with radiating venation, give origin to the terms lobed, cleft, and partite (figs. 161, 189). "When the divisions extend about half-way through the leaves, they may be three-lobed, five-lobed, seven-lobed, many-lobed ; or, trifid, quinquefid, septemfid, multifid, according to the number of divisions. The name of palmate, or palmatifid (fig. 159), is the general term applied to leaves with radiating venation, in which there are several lobes united by a broad expansion of parenchyma, like the palm of the hand, as in Passion-flower and Rheum palmatum. The divisions of leaves with radiating venation may extend to near the base of the leaf, and the names bipartite, tripartite, quinque- partite or digitipartite, and septempartite, are given according to the number of the partitions, two, three, five, or seven. In Drosera dichotoma (fig. 88), bipartite and tripartite leaves are seen. The term dissected is applied to leaves with radiating venation, having numerous narrow divisions, as in Geranium dissectum. When in a radiating leaf there are three primary partitions and two lateral ones, spreading and forming divisions on their inner margin only, as in Helleborus (fig. 185), the leaf is called pedate or pedatifid (pes, a foot), from a fancied resemblance to the claw of a bird. In all the instances already alluded to the leaves have been considered as flat expansions, in which the ribs or veins spread out on the same planes with the stalk. In some cases, however, the veins spread at right angles to the stalk. If they do so equally on all sides, and are united by parenchyma, so that the stalk occupies the centre (fig. 160), the leaf becomes orbicular (orbis, a circle), as in Hydrocotyle ; if unequally, so that the stalk is not in the centre, the leaf is peltate 88 FORMS OF SIMPLE LEAVES. (pelta, a buckler), as in the Castor-oil plant (fig. 161). The edges or margins of orbicular and peltate leaves are often variously divided. . It has been thought by some that the order of the venation in the leaf bears a close analogy to the ar- rangement of the branches on the stem ; that a cer- tain unity so pervades vegetable organisation, that the root, the stem, and the leaves, may, in their ultimate arrange- ment, be regarded as being typical the one of the Eig: 16; Fig. 161, other. M‘Cosh states, that the angles at which the veins are given off in the leaves are the same as those at which the branches come off from the stem. The angles as given by him vary from 30° to 70°.* Without attempting to notice all the forms of leaves, the following are enumerated as the most important. When the veins do not spread out, but run from the base to the apex with a narrow strip of paren- chyma, the leaf is linear or acicular (acus, a needle), (fig. 162), as in Pines and Firs. These trees are hence called in Germany nadel- holzer, or needle trees. When the veins diverge, those in the middle being longest, and the leaf tapering at each end (fig. 181), it be- Figs. 162, 163, 164. 165. 166. 167. 168. 169, Fig. 160. Orbicular leaf of Hydrocotyle vulgaris. Radiating venation. y, Petiole. 1, Lamina. Fig. 161. Peltate leaf of the Castor-oil plant (Ricinus communis). Radiating venation. yp, Petiole or leaf-stalk. 1, Lamina or blade. Fig. 162. Linear, or acicular leaf of Fir. Fig. 163. Spathulate leaf of Daisy. Fig. 164. Oval leaf. Fig. 165. Oblong leaf. Fig. 166, Petiolated, reticulated, somewhat oblong leaf, truncate at the base. Fig. 167. Ovate pointed leaf. Fig. 168. Cordate pointed leaf. Fig. 169. Ovato-lance- olate leaf, 4.e, lanceolate in its general contour, but ovate at the base ; doubly serrated, or having large and small serratures alternately at the margin. * M‘Cosh on the plant morphologically considered. Proceed. of the Edin. Bot. Soc., July 1851. Bot. Gazette, September 1851. FORMS OF SIMPLE LEAVES. : 89 comes lanceolate (lancea, a lance). If the middle veins only exceed the others slightly, and the ends are convex, the leaf is either rounded (rotundatus), as in fig. 179, elliptical (fig. 177), oval (fig. 164), or oblong (fig. 165). If the veins at the base are longest, the leaf is ovate or egg-shaped, as in Chickweed (fig. 167), and if those at the apex are longest, the leaf is obovate, or inversely egg-shaped. Leaves are cuneate (cuneus, a wedge) or wedge-shaped, in Saxifraga (fig. 170) ; spathulate, or spatula-like, having a broad rounded apex, and tapering down to the stalk- in the Daisy (fig. 163); subulate (fig. 182), . narrow and tapering like an awl (subula); acuminate, or drawn out into a long point, as in Ficus religiosa (fig. 174), mucronate, with a hard stiff point or mucro at the apex (figs. 175 and 158), When 170. 171, 172. 173. 174, 175, the parenchyma is deficient at the apex so as to form two rounded lobes, the leaf is obcordate or inversely heart-shaped ; when the deficiency is very slight, the leaf is called emarginate (fig. 158) as having a portion taken out of the margin; when the apex is merely flattened or slightly depressed (fig. 172), the leaf is retuse (retusus, blunt) ; and when the apex ends abruptly in a straight margin, as in the Tulip tree (fig. 178), the leaf is trun- cate, When the venation is prolonged downwards at an obtuse angle with the midrib, and rounded lobes are formed, oni ; ; sian Dog-yiolet, tte leaf is Fig. 176. Fig. 177. Fig. 178. cordate or heart-shaped (fig. 168), or kidney-shaped (reniform) when the apex is rounded (fig. 176), as in Asarum. When the lobes are prolonged Fig. 170. Cuneate or wedged-shaped leaf of Saxifraga, ending in an abrupt or truncate manner, and toothed or dentate at the apex. Fig. 171. Perfoliate leaf of Bupleurum perfoliatum, formed by lobes uniting at the base on the opposite side of the stem from that to which the leaf is attached. Fig. 172. Retuse leaf, i.e. slightly depressed at the apex. Margin slightly waved. Fig. 173. Ovate five-ribbed leaf. Fig. 174. Rounded acuminated leaf of Ficus religiosa, with the margin crenate or slightly sinuous. Fig. 175. Sub-ovate, retuse, mucronate leaf. Fig. 176. Reniform or kidney-shaped entire leaf of Asarum. Radiating venation. Fig. 177. Elliptical and-somewhat lanceolate leaf; three- ribbed. Fig. 178. Three-lobed, truncate, or abrupt leaf of Liriodendron tulipiferum. 90 FORMS OF SIMPLE LEAVES. downwards and are acute (fig. 180), the leaf is sagittate (sagitta, an arrow) ; when they proceed at right angles, as in Rumex Acetosella, the leaf is hastate (hasta, a halbert) or halbert-shaped. When a simple leaf is divided at the base into two leaf-like appendages (fig. 184), it is called awriculate (auricula, little ear). When the veins spread out in various planes, and there is a large development of cellular tissue, so as 179. 180, 181. 182. to produce a succulent leaf, such forms occur as conical, prismatical, ensiform or sword-like (ensis, a sword), acinaciform (acinaces, a scimitar) or scimitar-shaped (fig. 187), and dolabriform (dolabra, an axe) or axe-shaped (fig. 186). When the development of cells is such that they more than fill up the spaces between the veins, the margins become wavy, crisp, or wndulated, as in Rumex crispus and Rheum undulatum (fig. 189). By cultivation the cellular tissue is often Figs. 185. 186. 187, 188. 189. much increased, giving rise to the curled leaves of Greens, Savoys, Cresses, Lettuce, etc. In rushes the shoots which act as leaves are Fig. 179. Rounded entire leaf, ending in a short point. Fig. 180. Sagittate or arrow- shaped leaf of Sagittaria. Fig. 181. Lanceolate, acute leaf, with minute teeth or dentations atthe margin. Fig. 182. Subulate or awl-shaped leaf. Fig. 183. Whorl or verticil of linear-obovate leaves, Fig. 184. Auriculate lanceolate leaf, oblique at the base, with minute toothings at the margin. Fig. 185. Pedate or Pedatifid leaf of Hellebore. Radi- ating venation. Fig. 186. Dolabriform or axe-shaped fleshy succulent leaf. Hidden- veined. Fig. 187, Acinaciform or scimitar-shaped succulent leaf. Hidden-veined. Fig. 188. Oval leaf with converging veins; not reticulated. Fig, 189, Palmately-lobed leaf, crisp or undulated at the margin. Radiating venation. , FORMS OF COMPOUND LEAVES. 91 often terete. They are either barren or bear flowers. Their cellular tissue is often stellate, and the shoots some- times exhibit a pe- culiar spiral twisting. (Fig. 190.) CompouND LEAVES are those in which the divisions extend to the midrib, or petiole (fig. 191), and receive the name of foliola or leaf- lets, The midrib, or petiole, has thus the appearance of a branch with separate leaves attached to it, but it is considered properly as one leaf, because in its earliest state it arises mT TINT UT Nat Fig. 190. Fig. 191. Fig. 192, Fig. 190. Juncus effusus, variety, with spiral leaves, called Screw-rush. _. Fig. 191, Leaf of Robinia pseudacacia, often called Acacia, The leaf is impari-pinnate, or alternately pin- nate. The pinnew are supported on stalks or petiolules. , Petiole or leaf-stalk. 1, Lamina -- or blade divided into separate leaflets or pinne, Fig. 192. Septenate leaf of Horse Chest~- nut (4sculus Hippocastanwm). pp, Petiole. 1, Lamina divided into seven separate leaflets. 92 FORMS OF COMPOUND LEAVES, from the axis as a single piece, and its subsequent divisions in the form of leaflets are all in one plane. The leaflets are either sessile (fig. 192), or have stalks, called petiolules (fig. 191), according as the vascular bundles of the veins spread out or divaricate at once, or remain united for a certain length. Compound leaves have been classified according to the nature of the venation, and the development of parenchyma. If we suppose that in a simple feather-veined unicostate leaf, the divisions extend to the midrib, and each of the primary veins spreads out or branches so as to become covered with parenchyma, and thus form separate leaflets, which are usually articulated to the petiole or midrib (fig. 193), the leaf becomes compound and pinnate (pinna, a wing or feather), If the midrib and primary veins are not covered with parenchyma, ent PAC Bs HNN Fig. 194. Fig. 195. while the secondary (or those coming off in a feather-like manner from the primary veins) are, and separate leaflets are thus formed which are usually articulated with the veins, the leaf is bipinnate (fig. 194). In this case the secondary veins form as it were partial petioles, A farther subdivision, in which the tertiary veins only are covered with parenchyma and have separate leaflets, gives tripinnate or decompownd, in which case the tertiary veins form the partial petioles; and a leaf divided still more is called supradecompound (fig. 195). When a pinnate leaf has one pair of leaflets, it is unijugate (unum, one, and jugum, a yoke); when it has two pairs, it is bijugate; many Fig. 193. Pari-pinnate leaf with six pairs of pinne (seajugate). Fig. 194. Bipinnate leaf, with sessile foliola or leaflets, Fig. 195. Part of the supradecompound leaf of Laserpitium hirsutum. FORMS OF COMPOUND LEAVES. 93 pairs, multijugate (fig. 191). When a pinnate leaf ends in a pair of pinne (fig. 193) it is equally or abruptly pinnate (pari-pinnate) ; when there is a single terminal leaflet (fig. 191), the leaf is unequally pinnate (impari-pinnate) ; when the leaflets or pinne are placed alternately on either side of the midrib, and not directly opposite to each other, the leaf is alternately pinnate (fig. 191); and when the pinne are of dif- ferent sizes, the leaf is interruptedly pinnate (fig. 196). In the case of a simple multicostate leaf with radiating venation, if we suppose the ribs to be covered with parenchyma, so as to form separate leaflets, each of which is articulated to the petiole, the digitate form of compound leaf is produced ; if there are three leaflets, the form AN SX Ne "KS 1 Fig. 196. Fig. 197. Fig. 198. is ternate (figs. 156, 197); if four, quaternate (fig. 157); if five, quinate ; if seven, septenate (fig. 192), and so on. If the three ribs of a ternate leaf subdivide each into three primary veins, which become covered with parenchyma so as to be separate articulated leaflets, the leaf is biternate ; and if another three-fold division takes place, it is triternate fig. 198). : pee summary of facts connected with the venation and con- formation of leaves :— 1. Leaves of flowering plants are either netted-veined (reticulated) or parallel- veined. . 2. Leaves have either a single midrib (unicostate), or several ribs (multicostate); and the latter are either radiating (spreading out from one point), or con- ‘vergent. 3. Unicostate leaves have veins proceeding at different angles from various points of the midrib, and arranged more or less like the parts of a feather. Fig. 196. Impari- alternately and interruptedly pinnate leaf. Leaflets or pinne sessile, and serrated at the margin. Fig. 197. Ternate leaf of Strawberry, Margin of leaflets, toothed or dentate. ip, Petiole with projecting hairs. 2, Lamina divided into three leaflets. Fig. 198. Triternate leaf. Leaflets cordate. 94. FORMS OF PETIOLES OR LEAF-STALKS. 4, The conformation of leaves depends partly on the venation, and partly on the mode in which the parenchyma is developed. 5. Leaves are either simple, ¢.e. composed of one piece, or compound, 7.¢. com- posed of one or more articulated leaflets. 6. Simple leaves are either entire or divided into segments. When the divisions are marginal, they are dentate, serrate, or crenate ; when the divisions are deeper, cleft or partite. 7. Simple unicostate (one-ribbed) leaves having their parenchyma cut laterally into various lobes, so that the divisions extend to about the middle of each half of the lamina, may be referred to the Pinnatijid type, including bipinnatifid, pectinate, panduriform, runcinate, and lyrate forms ; when the divisions extend nearly to the midrib the form is pinnati-partite. 8, Simple multicostate (many-ribbed) leaves, with the ribs divergent, when cut longitudinally into various lobes, the divisions extending to about the middle of the lamina, may be referred to the Palmatifid type, including trifid, quinquefid, pedate, and dissected forms ; when the divisions extend to near the base the forms are palmately-partite or dissected. 9, Simple leaves, with convergent ribs, are rarely divided deeply, and such is also the case with parallel-veined leaves, the margins of which are often entire. 10. Simple leaves, whether unicostate or multicostate, with lobes or divisions at their base, exhibit reniform, cordate, sagittate, and hastate forms; with lobes or divisions at their apex, emarginate and obcordate forms. 11. Compound unicostate leaves, having lateral articulated leaflets, may be referred to the Pinnate type, including bipinnate, tripinnate, and decom- pound forms. 12. Compound multicostate leaves, with divergent ribs, divided longitudinally into articulated leaflets, may be referred to the Digtiate type, including ternate, triternate, quaternate, and quinate forms. PetioLe oR Lear-SraLK.—This is the part which unites the limb or blade of the leaf to the stem (figs. 147 and 191 p). It is absent in sessile leaves, and in many sheathing leaves is not well defined. It consists of one or more bundles of vascular tissue, with a varying amount of parenchyma. The vessels are spiral vessels, connected with the medullary sheath in Exogens, and with the fibro-vascular bundles in Endogens, porous vessels and other forms of fibro-vascular tissue, woody tissue, and laticiferous vessels. These vessels are enclosed in an epidermal covering, with few stomata, and are more or less compressed. When the vascular bundles reach the base of the lamina they separate and spread out in various ways, as already described under venation. A large vascular bundle is continued through the lamina to form the midrib (fig. 148, » m), and sometimes several large bundles form separate ribs (figs. 161, 177), whilst the ramifications of the smaller bundles constitute the veins and veinlets. At the place where the petiole joins the stem there is frequently an articulation, or a constriction with a tendency to disunion, and at the same time there exists a swelling (fig. 220 p), called pulvinus (pulvinus, a cushion), formed by a mass of cellular tissue, the cells of which occasionally exhibit the phenomenon of contractility. At other times the petiole is not articulated, but is either continuous with the stem, or forms a sheath around it. At the point where the petiole is FORMS OF PETIOLES OR LEAF-STALKS. 95 united to the lamina, or where the midrib joins the leaflets of a com- pound leaf, there is occasionally a cellular dilatation called struma (struma, a swelling), with an articulation. This articulation or joint is by many considered as indicating a compound leaf, and hence the leaf of the orange is considered as such, although it consists of one undivided lamina (fig. 201). In articulated leaves, the pulvinus may be attached either to the petiole or to the axis, and may fall with the leaf, or remain attached to the stem. When articulated leaves drop, their place is marked by a cicatrix or scar, seen below the bud in fig. 220, In this scar the remains of the vascular bundles, ¢, are seen ; and its form furnishes characters by which particular kinds of trees may be known when not in leaf. In the case of many Palms and Tree-ferns, the scars or cicatrices of the leaves are very conspicuous, In fossil plants important characters are founded on them. | The petiole varies in length, being usually shorter than the lamina, but some- times much longer. In some Palms it is fifteen or twenty feet long, and is so firm as to be used for poles or walking-sticks, In Fig. 199. "Fig. 200. Fig. 201. general, the petiole is more or less rounded in its form, the upper surface being flattened or grooved. Sometimes it is compressed laterally, as in the Aspen, and to this peculiarity the trembling of the leaves of this tree is attributed. In aquatic plants, the leaf-stalk is sometimes distended with air (fig. 199 p), as in Pontederia and Trapa, so as to float the leaf. At other times it is. winged, or has a leaf-like appearance, as in the pitcher plant (fig. 200 p), orange (fig. 201 p), Fig. 199. Leaf with a quadrangular toothed lamina or blade, J, and an inflated petiole, p, containing air-cells. Fig. 200. Ascidium or pitcher of Nepenthes. , Winged petiole which becomes narrowed, and then expands so as to form the pitcher a, by folding on itself. e, The operculum or lid, supposed to be formed by the blade of the leaf, and articu- ‘lated to the pitcher. Fig. 201. Leaf of Orange, which some call compound. 9, Dilated or winged petiole, united by an articulation to the blade. In such a leaf, if the vessels of the petiole were developed in a circular manner, so as to form a pitcher, the lamina or blade would form the jointed lid. ~ 96 FORMS OF PETIOLES OR LEAF-STALKS. lemon and Dionza (fig. 202 p). In some Australian Acacias, and in some species of Oxalis, Bupleurum, etc., the petiole is flattened in a vertical direction, the vascular bundles separating immediately after quitting the stem, and running nearly parallel from base to apex. This kind of petiole (fig. 204 p) has been called Phyllodiwm (piAaroy, a leaf, and ¢760¢, form). In these plants the laminz or blades of the leaves are pinnate, bipinnate, or ternate, and are produced at the extremities of the phyllodia in a horizontal direction (fig. 204 2) ; but Fig. 202. Fig. 203. Fig. 204. in many instances they are not developed, and the phyllodium serves the purpose of a leaf. Hence some Acacias are called leafless. These phyllodia, by their vertical position and their peculiar form, give a remarkable aspect to vegetation. On the same Acacia, there occur leaves with the petiole and lamina perfect; others having the petiole slightly expanded or winged, and the lamina imperfectly developed ; and others in which there is no lamina, and the petiole becomes large and broad. Some petioles, in place of ending in a Fig. 202. Leaf of Dionza muscipula, or Venus’ Fly-trap. p, Dilated or winged petiole. e, Jointed blade, the two fringed halves of which fold on each other, when certain hairs on the upper surface are touched, Fig. 2038, Ascidium, or Pitcher of Sarracenia, formed by the petiole of the leaf. The lid is not articulated to the pitcher as in Nepenthes (fig. 200). Fig. 204, Leaf of Acacia heterophylla. p, Phyllodium or enlarged petiole, with straight venation. 11, Lamina or blade, which is bipinnate. The blade is fréquently wanting, and the phyllodium is the only part produced. STRUCTURE AND FORMS OF STIPULES. 97 lamina, form a tendril or cirrus (p. 120), so as to enable the plant to climb. Stipules. At the place where the petiole joins the axis, a sheath (vagina) is sometimes produced, which embraces the whole or part of the cir- cumference of the stem (fig. 147 g). This sheath is formed by the divergence of the vascular bundles, which separate so as to form a hollow cavity towards the stem. The sheath is occasionally developed to such a degree as to give a character to the plants, Thus, in the Rhubarb order, it is large and membranous, and has received the name of ochrea or boot (fig. 147 g) ; while in Palms it forms a kind of net- work, to which the name of reticulum has been given (p. 32); and in umbelliferous plants it constitutes the pericladiwm (wegi, around, and xAd6os, a branch). In place of a sheath, leaves are occasionally pro- duced at the base of the petiole (fig. 205 ss), which have been denominated stipules (stipula, straw or husk). These stipules are often two in number, and they are important as sup- plying characters in certain natural orders, Thus they occur in the Pea and Bean family, in Rosaceous plants, and the Cinchona bark family. They are rarely met with in Mono- cotyledons, or in Dicotyledons with sheath- ing petioles, and they are not common in Dicotyledons with opposite leaves. Plants having stipules are stipu- late; those having none are exstipulate. Stipules are formed by some of the vascular bundles diverging as they leave the stem, and becoming covered with parenchyma, so as to resemble true leaves. Like leaves they are large or small, entire or divided, deciduous or persistent, articulated or non-articulated. Their lateral position at the base of the petiole distinguishes them from true leaves. In the Pansy the true leaves are stalked and crenate, while the stipules: are large, sessile, and pinnatifid. In Lathyrus Aphaca, and some other plants, the true pinnate leaves are abortive, the petiole forms a tendril, and the stipules alone are developed, perform- .. ing the office of leaves. When stipules are attached separately to the stem at the base of the leaf, they are called caulinary. Thus, in fig. 205, r is a branch of Salix aurita, with a leaf, f, having a bud, b, in its axil, and two caulinary stipules, s s. When stipulate leaves are opposite to each other, at the same height on the stem, it occasionally happens that the Fig. 205. a Fig. 205. Portion of a branch, 7, of Salix aurita bearing a single petiolate leaf, f, which has been cut across. . ss, Caulinary stipules. b, Bud in the axil of the leaf, H 98 FORMS OF STIPULES. stipules on either side unite wholly or partially, so as to form an inter- petiolary or interfoliar (inter, between) stipule (fig, 206 s), as in Cin- chona and in Ipecacuan. In the case of alternate leaves, the stipules at the base of each leaf are sometimes united to the petiole and to each other, so as to form an adnate, adherent, or petiolary stipule, as in the Rose (fig, 207 s), or an asillary stipule, as in Houttuynia Fig. 208, Fig. 209. cordata (fig. 208 s). In other instances the stipules unite together on the side of the stem opposite the leaf, and become synochreate (oty, together), as in Astragalus (fig. 209 s). The union or adhesion of. Fig. 206. Branch, r, and two leaves, ff, of Cephalanthus occidentalis. s, Interpetiolary or interfoliar stipule, formed by the partial union of two. Fig. 207. Portion of a branch, r, of Rosa canina, or dog-rose, bearing a single. leaf, f, with its petiole, p, its petiolary or adnate stipules, s, its axillary bud, b, and its aculei or prickles, a. Fig. 208. Portion of a branch, 7, of Houttuynia cordata, with a leaf, f, and an axillary stipule, s, formed by the union of two. Fig. 209. Branch, 7, and portion of the leaf, f, of Astragalus Onobrychis, with a synochreate stipule, s, formed by the union of two stipules on the opposite side of the branch from that to which the leaf is attached. The leaf is pinnate, and in the figure three pairs of leaflets or pinnz are left. ANOMALOUS LEAVES AND PETIOLES. 99 stipules is not an accidental occurrence taking place after they have been developed, but is intimately connected with the general law, in accordance with which the parts of the plants are formed. Stipules are sometimes large, enveloping the leaves in the young state, and falling off in the progress of growth, as in Ficus, Magnolia, and Potamogeton ; at other times they are so minute as to be scarcely distinguishable without the aid of a lens, and so fugaceous as to be visible only in the very young state of the leaf. They may assume a hard and spiny character as in Robinia pseudacacia, or may be cirrose, as in Smilax, where each stipule is represented by a tendril ; while in Cucurbitaceze there is only one cirrose stipule. In grasses the sheath or sheathing petiole (fig. 210 g v) has a prolongation or fold- ing of the epidermis at its upper part, distinct from the leaf, to which the name of ligule (ligula, a small slip) has been given (fig. 210 97). Some consider it as equivalent to a stipule. It is either long or short, acute or blunt, entire or divided, and thus gives rise to various characters. At the base of the leaflets or foliola of a com- pound leaf, small stipules are occasionally pro- duced, to which some have given the name of stzpels, Anomalous Forms of Leaves and Petioles, Variations in the structure and forms of leaves and leaf-stalks . are produced by the increased development of cellular tissue, by the abortion or degeneration of parts, by the multiplication or repetition of parts, and by adhesion. When cellular tissue is developed to a great extent, leaves become succulent, and occasionally assume a crisp or curled appearance. Such changes take place naturally, but they are often increased by the art of the gardener ; and the object of many horticultural operations is to increase the bulk and succulence of leaves. It is in this way that Cabbages and Savoys are rendered more delicate and nutritious. In some plants true leaves are not produced, their place being occu- pied by dilated petioles or phyllodia (p. 96), or by stipules (p. 97). In other instances scales are formed instead of leaves, as in Orobanche, Lathrea, and young Asparagus (fig. 129 2). Divisions take place in Fig. 210. Portion of a leaf of Phalaris arundinacea, one of the grasses. f, Laminar merithal or blade of the leaf, with straight parallel venation. gv, Vaginal, or sheathing portion, representing the petiole, ending in a membranous process or ligule, g 1, 100 ASCIDIA OR PITCHERS. leaves when there is a multiplication of their parts; and a union of two or more leaves, or of parts of leaves, occurs in many cases. When two lobes at the base of a leaf are prolonged beyond the stem and unite (fig, 171), the leaf is perfoliate (per, through, and folium, leaf), the stem appearing to pass through it, as in Bupleurum perfolia- tum, and Chlora perfoliata ; when two leaves unite by their bases they become connate (con, together, and natus, born), as in Lonicera Caprifolium ; and when leaves adhere to the stem, forming a sort of winged or leafy appendage, they are decurrent (decurro, to run down or along), as in Thistles. The vascular bundles and cellular tissue are sometimes deve- loped in such a way as to form a circle, with a hollow in the centre, and thus give rise to what are called fistular (fistula, a pipe) or hollow leaves, and to ascidia (doxidsv, a small bag) or pitchers, Hollow leaves are well seen in the Onion. Pitchers are formed either by petioles or by laminz, and they are composed; of one or more leaves. In some Convallarias, two leaves unite to form a cavity. In Sarracenia (fig. 203) and Heliamphora, the pitcher is composed apparently of the petiole of the leaf. In Nepenthes (fig. 200) and perhaps in Cephalotus, while the folding of a winged petiole, », forms the pitcher, a, the lid, e, which is united by an articulation, corre- sponds to the lamina. This kind of ascidium is called calyptrimor- phous (xadrdrrpa, a covering, and joggq, form), and may be con- sidered as formed by a leaf such as that of the Orange (fig. 201) ; the lamina, ¢, being articulated to the petiole, », which, when folded, forms the pitcher. In Dischidia Rafflesiana, a climbing plant of India, the pitchers, according to Griffith, are formed by the lamina of the leaf, and have an open orifice into which the rootlets at the upper part of the plant enter. These pitchers would seem therefore to contain a supply of fluid for the nourishment of the upper branches of the plant. In Utricularia, the leaves form sacs called ampulla, Some suppose that pitchers are not due to folding and adhesion, but that they are produced by a hollowing out of the extremity of the stalk. Structure and Form of Leaves in the Great Divisions of the Vegetable Kingdom, Leaves or Dicotytepons.—In Dicotyledons, the venation is reticulated, the veins, coming off at various angles, form an angu- lar network of vessels (fig. 151), and the tracheze communicate with the medullary sheath. They are frequently articulated, ex- hibit divisions at their margin, and become truly compound. There are no doubt instances in which the veins proceed in a parallel man- ner, but this will be found to occur chiefly in cases where the petiole may be considered as occupying the place of the leaf. Examples of LEAVES OF EXOGENS, ENDOGENS, AND ACROGENS. 101 this kind are seen in Acacias (fig. 204), as well as in Ranunculus gramineus and R. Lingua. LEAVES OF MonocoryzEpons. —In Monocotyledons, the leaves do not present an angular network of vessels, nor do they exhibit divisions on their margin (figs. 150, 210). Exceptions to this rule occur in some plants, as Tamus and Dioscorea, which have been called Dictyogens by Lindley, on account of their somewhat netted venation ; and in Palms, in which, although the leaves are entire at first, they afterwards become split into various lobes. Leaves of Monocotyle- dons are rarely stipulate, unless the ligule of grasses be considered as. being a stipule. Their leaves are often sheathing, continuous with the stem (forming a spurious stem in Bananas), and do not fall off by an articulation. When there is only a slight divergence of their veins, they may be looked upon more as enlarged and flattened petioles than as true lamine. This remark is illustrated by the leaves of Typha and Iris. In some Monocotyledons, as in Sagittaria sagitti- folia, the submerged and floating leaves are narrow, like petioles, while those growing erect above the water expand and assume an arrow-like shape (fig. 180). Leaves of ACoTYLEDONS.—In Acotyledons, such as Ferns and their allies, the leaves vary much ; being entire or divided, stalked or sessile, often feather-veined, occasionally with radiating venation, the extremities of the veins being forked, The fibro-vascular bundles of the leaves resemble those of the stem both in structure and arrange- ment, In Thallogens, the leaves when present have no vascular venation. In many of them, as Lichens, Fungi, and Alge, there are no true leaves. Phyllotaais, or the Arrangement of the Leaves on the Axis, Leaves occupy various positions on the stem and branches, and have received different names according to their situation. Thus leaves arising from the crown of the root, as in the Primrose, are called radical; those on the stem are cauline ; on the branches, ramal ; on flower-stalks, floral leaves, The first leaves developed are deno- minated seminal (semen, a seed), or cotyledons (xorvAnday, a name given to a plant or a seed-lobe) ; and those which succeed are primordial (primus, first, and ordo, rank), The arrangement of the leaves on the axis and its appendages is called phyllotaxis (pbrAov, a leaf, and ré&s¢, order). In their arrange- ment leaves follow a definite order. It has been stated already, p. 45, that there are regular nodes or points. on the stem (fig. 211 n) at which leaves appear, and that the part of the stem between the nodes is the internode (fig. 211 m). Each node is capable of giving origin to a leaf. Occasionally several nodes are approximated so as to form 102 PHYLLOTAXIS OR LEAF-ARRANGEMENT, as it were one, and then several leaves may be produced at the same height on the stem. When two leaves are thus produced, one on Fig. 211. Fig. 212. each side of the stem or axis, and at the same level, they are called opposite (fig. 212) ; when more than two are produced (figs. 183, 213), they are verticillate (verto,I turn), and the circle of leaves is then called a verticil or whorl. When leaves are opposite, the pairs which are next each other, but separated by an internode, often cross at right angles (fig. 212 wb), or decussate (decusso, I cut cross- wise), following thus a law of alternation. The same occurs in verticils, the leaves of each whorl being alternate with those of the whorl next to it ; or, in other words, each leaf in a whorl occupying the space between two leaves of the whorl next to it. There are considerable irregularities, however, in this respect, and the number Fig. 218. of leaves in different whorls is not always uniform, as may be seen in Lysimachia vulgaris (fig. 213). Fig. 211. Portion of a branch of a Lime tree, with four leaves arranged in a distichous man- ner, or in two rows. a, The branch with the leaves numbered in their order, n being the node, and m the internode or merithal. 0 Is a magnified representation of the branch, showing the cicatrices of the leaves and their spiral arrangement, which is expressed by }, or one turn of the spiral and two leaves. Fig. 212. Opposite, decussate leaves of Pimelea decussata. a, A pair of opposite leaves. 6, Another pair placed at right angles. Fig. 218. Leaves of Lysimachia vulgaris, in verticils or whorls of three. The leaves of each ver- ticil alternate with those of the verticils next it. In this plant the number of the leaves in a verticil often varies, PHYLLOTAXIS OR LEAF-ARRANGEMENT. 103 When a single leaf is produced at a node, and the nodes are sepa- rated so that each leaf occurs at a different height on the stem, the leaves are alternate (fig. 214). The relative position of alternate leaves varies in different plants, although it is tolerably uniform in each species. In fig. 211, leaf 1 arises from a node, n; leaf 2 is separated by an internode, m, and is placed to the right or left ; while leaf 3 is situated directly above leaf 1. The arrangement in this case is distichous (dlc, twice, and cries, order), or the leaves are arranged in two rows. In fig. 215, on the other hand, the fourth leaf is directly above the first, and the arrangement is trist’chous (rge7, three, and oriyos, order). The same arrangement continues throughout the stems, so that in fig. 215 the 7th leaf is above the 4th, the 10th above the 7th; also the 5th above the 2d, the 6th above the 3d, and so on. There is thus throughout a tendency to a spiral arrangement, the number of leaves in the spire or spiral cycle, and the number of turns, varying in different plants. In. plants whose leaves are close to each other, the spiral tendency is easily seen. In the Screw pine (Pandanus odoratissimus), in the Pine-apple family, and in some Palms, as Copernicia cerifera, the screw-like arrangement of the leaves is obvious. This mode of development prevails in all parts of plants, and may be considered as depending on their manner of growth in an upward and at the same time in a lateral direction. Alternation is looked upon as the normal arrangement of all parts of plants. This arrangement is liable to be interrupted by many causes, so that its distinct existence cannot be always detected. In a regularly-formed straight branch covered with leaves, if a thread is passed from one to the other, turning always in the same direction, a spiral is described, and a certain number of leaves and of complete turns occur before reaching the leaf directly above that from which the enumeration commenced. This arrangement has been expressed by a fraction, the numerator of which indicates the number Fig. 214. Fig. 214. Part of a branch of a Cherry with six leaves, the 6th being placed vertically over the first, after two turns of the spiral. This is expressed by 2 or the quincunx. a, The branch, with the leaves numbered in order. b, A magnified representation of the branch, showing the cicatrices of the leaves or their points of insertion, and their spiral arrangement, 104 PHYLLOTAXIS OR LEAF-ARRANGEMENT. of turns, and the denominator the number of leaves in the spiral cycle. Thus, in fig. 214, a 6, the cycle consists of five leaves, the 6th leaf being placed vertically over the Ist,’ the 7th over the 2d, and so on; while the number of turns between the Ist and 6th leaf is two: hence, this arrange- ment is indicated by the fraction 2, In other words, the distance or divergence between the first and second leaf, ex- pressed in parts of a circle, is2 of a circle, or 360° +%=144°. In fig. 211, a b, the spiral is 4, 7.2. one turn and two leaves ; the third leaf being placed verti- cally over the first, and the divergence between the first and second leaf being one-half the circumference of a circle, 360°+4 = 180°. Again, in fig, 215, ab, the number is %, or one turn and : three leaves, the angular divergence being Fig. 215. 120°. The general forms of Phyllotaxy may be brought out by a con- tinued fraction— 1 a+1+1+4+141, ete, where a may have the values 1, 2, 3, or 4, ete. The actual fractions thus resulting are—when a= 1.432 £ 4s, ete a= 2... 42 2 4s, ete. @ = 3..3 £ # sr ae, ete. a= 4.44 % 3% as, ete. Each fraction being obtained by adding together the numerator and denominator in the two preceding fractions. When the leaves or scales are alternate, and run in a single series, they are unijugate ; when the leaves are opposite, and there are two parallel rows produced, the arrangement is bijugate, while in the case of whorled leaves the arrangement may be trijugate or quadrijugate. Fig. 215.—Young plant of Cyperus esculentus, with leaves in three rows, or tristichous, expressed by the fraction 3, or one turn and three leaves. a, The plant, with its leaves numbered in their order. b, Magnified representation of the stem, showing the insertion of the leaves and their spiral arrangement, PHYLLOTAXIS OR LEAF-ARRANGEMENT. 105 In cases where the internodes are very short, and the leaves are closely applied to each other, as in the House-leek, it is difficult to trace what has been called the generating spiral, or that which passes through every leaf of the cluster. Thus in fig. 216, there are thirteen leaves which are numbered in their order, and five turns of the spiral marked by circles in the centre (,, indicating the arrangement) ; but this could not be detected at once. So also in Fir cones (fig. 217), which are composed of scales or modified leaves, the generating spiral cannot be determined easily. In such cases, however, there are secondary spirals running parallel to each other, as is seen in fig. 217, where spiral lines pass through scales numbered 1, 6, 11, 16, etc., ‘ Fig. 216. Fig. 217. and 1, 9, 17, etc., and by counting those which run parallel in differ- ent directions, the number of scales intervening between every two in the same parallel coil may be ascertained. Thus, in fig. 217, it will be found that there are five secondary spirals running towards the right and parallel to each other, the first passing through the scales 1, 6, 11, 16, ete. ; the second through 9, 14, 19, 24, etc.; the third through 17, 22, 27, 32, 37, etc. ; the fourth through 30, 35, 40, 45, etc. ; the fifth through 43, 48, 53, etc. -The number of these second- ary spirals indicates the number of scales intervening between every Fig. 216. Cycle of thirteen leaves placed closely together so as to form a rosette, as in Sempervivum. A is the very short axis to which the leaves are attached. The leaves are numbered in their order, from below upwards. The circles in the centre indicate the five turns of the spiral, and show the insertion of each of the leaves. The divergence is expressed by the fraction 5-thirteenths. Fig. 217. Cone of Abies alba, with the scales or modified leaves numbered in the order of their arrangement on the axis of the cone. The lines indicate a rectilinear series of scales, and two lateral secondary spirals, one turning from left to right, the other from right to left. 106 PHYLLOTAXIS OR LEAF-ARRANGEMENT, two scales in each of these spirals—the common difference being five. Again, it will be found on examination that there are secondary spirals running to the left, in which the common difference between every two scales is eight, and that this corresponds to the number of secondary spirals, the first of which passes through the scales 1, 9, 17, etc. ; the second through 6, 14, 22, 30,-etc. ; the third through 5 11, 19, 27, 35, 43, and so on. Thus it is that, by counting the secondary spirals, all the scales may be numbered, and, by this means the gene- rating spiral may be discovered. In the cone of the American larch (fig. 218) there is a quincuncial arrangement of scales marked by the fraction 3. There are five vertical ranks, as marked in the tabular numerical view at the side of 15: : ; : thecone—viz.,2,7,12; 4,9, 14; 1, 6,11; >: i i14 i 38, 8,13; 5, 10, 15, the common difference :138 : : + in each row being 5. On looking at the cone ad : 12 we find also parallel oblique ranks, two of 1 i: i : Which, ascending to the left, are marked by : 9 : the numbers 1, 3, 5, which, if the diagram 8 : : : is coiled round a cylinder, continue in the : : 7 numbers 7, 9, 11, 13, 15; and 2, 4, 6, 8, : : } 10, continued into 12,14. There are thus Fig. 2, : : 4 : two left-handed spirals, with 2 as the com- : : 3 : : : mon difference in the numbering of the scales. : : : 2 Again, three oblique: parallel spirals ascend 1: = to the right, marked by the numbers 1, 4, 7, running into 10, 13; 3, 6, 9, 12, going on to 15; and 5, 8, a 14: here the common ‘numbering of the scales is 3, corresponding with the oblique right-handed spirals. The primitive or generating spiral may pass either from right to left or from left to right. It sometimes follows a different direction in the branches from that pursued in the stem. When it follows the same course in the stem and branches, they are homodromous (éwors, similar, and dgémos, a course) ; when ‘the direction differs, they are heterodromous (éregos, another or diverse), In different species of the same genus the phyllotaxis frequently varies. Considering alternation as the usual leaf-arrangement, some have supposed that opposite leaves are due to the development of two spirals in opposite directions, while others look upon them as pro- duced by two nodes coming close together without an internode. A verticil, in the latter view, will be the result of the non-development of more than one internode, and may occur in plants, the normal Fig. 218. Cone of a species of Larch (Laria microcarpa), taken from Professor Asa Gray’s work, with the scales numbered so far as seen, The arrangement is in the five- ranked series. There are five vertical rows of scales, 1, 6, 11; 4, 9, 14; 2, 7,12; 5, 10,15; and 3, 8, 13, as shown in the diagram. PHYLLOTAXIS OR LEAF-ARRANGEMENT. 107 arrangement of whose leaves is alternate. Thus, in fig. 211, if the space between 1 and 2 were obliterated, or the internode, m, not developed, the leaves would be opposite. In fig. 214, if the spaces between each of the leaves were obliterated, there would be a verticil of five leaves. In many plants there is a law of arrestment of development, by which opposite and verticillate leaves are naturally produced: but in such cases the alternation is still seen in the arrangement of the different clusters of leaves. / In some cases the effect of interruption of growth, in causing alternate leaves to become opposite and verticillate, can be distinctly shown, as for instance in Rhododendron ponticum. In other cases, . parts which are usually opposite or verticillate become alternate by the vigorous development of the axis: and on different parts of the same stem, as in Lysimachia vulgaris, there may be seen alternate, opposite, and verticillate leaves. When the interruption to develop- ment takes place at the end of a branch the leaves become fasciculate (fascicudus, a bundle) or clustered, as in the Larch. A remarkable instance of the shortening of internodes and the clustering of leaves occurred in the Palm-house of the Botanic Garden of Edinburgh, in the case of a Bamboo, which was exposed for many months to a low temperature, during the time that the roof of the house was being renewed. The plant had been growing rapidly, with its internodes of the usual length, but it was suddenly arrested near the summit, the internodes became gradually shortened, till the nodes were close to each other, and the leaves came off in bunches. All modifications of leaves follow the same laws of arrangement as true leaves—a fact which is of importance in a morphological point of view. In Dicotyledonous plants, the first leaves produced, or the cotyledons, are opposite. This arrangement often continues during the life of the plant, but at other times it changes. Some tribes of plants are distinguished by their opposite or verticillate, others by their alternate, leaves. Labiate plants have decussate leaves, while Boraginacez have alternate leaves, and Tiliacez usually have distichous leaves ; Cinchonaceze have opposite leaves; Galiacee, verticillate. Such arrangements as 2, 3, ,5,, and 8, are common in Dicotyledons. The first of these, called guincunsx (quincunz, an arrangement of five), is met with in the Apple, Pear, and Cherry (fig. 214); the second, in the Bay, Holly, Plantago media; the third, in the cones of Pinus (Abies) alba (fig. 217); and the fourth, in those of the Pinus (Abies) Picea. In Monocotyledonous plants there is only one seed-leaf or cotyledon produced, and hence the arrangement is at first alternate ; and it generally continues so more or less. Such arrangements as 4,4 (fig. 215), and 2, are common in Monocotyledons, as in Grasses, Sedges, and Lilies. In Acotyledons the leaves assume all kinds of arrangement, being opposite, alternate, and verticillate. It has been 108 LEAF-BUDS AND BRANCHES. found in general that, while the number 5 occurs in the phyllotaxis of Dicotyledons, 3 is common in that of Monocotyledons. Although there is thus, in the great divisions of the vegetable kingdom, a tendency to certain definite numerical arrangements, yet there are many exceptions. In speaking of Palms, which are Mono- cotyledonous plants, Martius states that the leaves of different species exhibit the following spirals—s, 2, $, & 5, fs, 3%, 34. In the species of the genus Pinus, 2, +, 2%, 4%, #4, occur. Thus, while it has been shown that the phylloplastic (g4AAo», a leaf, and tAworixéc, formative) or leaf-formative power moves in a spiral round the axis, it has been found impossible to apply phyllotaxis satisfactorily to the purposes of classification. The spiral arrangement of the leaves allows all of them to be equally exposed to air and light, and thus enables them to carry on their functions with vigour. The form of the stem is also probably connected with the leaf-arrangement. M. Cagnat has remarked that an analogy in arrangement of leaves and character of stem may be traced. The leaves of juniper are in verticils of three, and the pith is triangular ; the leaves of cypress being opposite, the pith presents the form of across. When. leaves are opposite and decussate, the stems are often square, as in Labiate plants. The ordinary rounded stem appears to be associated with a certain degree of alternation in the separate leaves, or in the different pairs of leaves when they are opposite. The study of the structure, forms, and arrangement of leaves, is of great importance, when it is considered that all parts of plants are to be looked upon as leaf-formations variously modified, in order to serve special purposes in the economy of vegetation. The morpho- logical relations of leaves, or the varied forms which they assume, will be illustrated during the consideration of the organs of reproduction, and of the doctrine of metamorphosis, as propounded by Goethe and others. It is only by looking upon all the organs of plants in their relation to the leaf as a type, that a philosophical view can be given of the great plan on which they have been formed. Leaf-buds, Lzar-Bups contain the rudiments of branches, and are found in the axtl of previously-formed leaves (fig. 219 ba, ba, ba); or, in other words, in the angle formed between the stem and leaf. They are hence called aazl/ary, and may be either terminal, bt, or lateral, ba, They commence as cellular prolongations from the medullary rays bursting through the bark. The central cellular portion is surrounded by spiral vessels, and is covered with rudi- mentary leaves. In the progress of growth, vascular bundles are LEAF-BUDS AND BRANCHES. 109 formed continuous with those of the stem; and, ultimately, branches are produced, which in every respect resemble the axis whence the buds first sprang. The cellular portion in the centre remains as pith with its medullary sheath, which is closed and not continuous with that of the parent stem, Thus, in the stem and “branch, this sheath forms a canal which. is closed at both extremities, and which’ sends prolongations of spiral vessels to the leaves. As the axis or central portion of the leaf-bud increases, cellular projections appear at regular intervals, which are the rudimentary leaves. A leaf-bud may be removed in a young *-— state from one plant and grafted upon another, by the process of budding, so as to continue to form its different parts; and it may even be made to grow in the soil, in some instances, immediately after removal. In certain cases leaf-buds are naturally detached during the life of the parent, so as to form independent plants, and thus propagate the individual. Leaf- buds have on this account been called fiwed embryos, by Petit-Thouars and others, who’ look upon them as embryo plants fixed to the axis, capable of sending stems and leaves in an upward direction, and bast or ligneous fibres downwards, which, according to them, may be con- sidered as roots. A tree may thus be said to consist of a series of leaf-buds, or phytons (purty, a plant), attached to a common axis or trunk. In ordinary trees, in which there is provision made for the formation of numerous lateral leaf-buds, any injury done to a few branches is easily repaired ; but in Palms, which only form central leaf-buds, and have no provision for a lateral formation of them, an injury inflicted on the bud in the axis is more likely to have a prejudicial effect on the future life of the plant. In the trees of temperate and cold climates the buds which are developed during one season lie dormant during the winter, ready to burst out under the genial warmth of spring. They are generally protected by external modified leaves in the form of scales, teymenta or perule (tegmenta, coverings ; perule, small bags), which frequently exhibit a firmer and coarser texture than the leaves themselves, These scales or protective appendages of the bud consist either of the altered lamine, or of the enlarged petiolary sheath, or of stipules, as in the Fig and Magnolia, or of one or two of these parts combined. Fig. 219. Fig. 219. Upper portion of a branch of Lonicera nigra in a state of hibernation, that is to say, after the fall of the leaves ; covered with leaf-buds. 6%, A terminal bud. ba, ba, ba, Axillary lateral buds. Below the buds the cicatrix or scar left by the fallen leaves is seen, 110 VERNATION OR PRAFOLIATION. They serve a temporary purpose, and usually fall off sooner or later after the leaves are expanded. The bud is often protected by a coat- ing of resinous matter, as in the Horse-chestnut and Balsam poplar, or by a thick downy covering, as in the Willow. Linnzus called leaf- buds Aibernacula, or the winter quarters of the young branch. In the bud of a common tree, as the Sycamore (fig. 220), there is seen the cicatrix left by the leaf of the previous year, c, with the pulvinus or swelling, p, then the scales, ¢ ¢, arranged alternately in a spiral manner, and overlying each other in what is called an imbricated (imbrex, a roof tile) manner. On making a transverse section of the bud (fig. 221), the overlying scales, ¢ ¢ ¢ ¢, are dis- tinctly seen surround- ing the leaves, f, which are plaited or folded round the axis orgrow- ing point. In plants of warm climates the- buds are often formed by the ordinary leaves without any protecting appendages ; such leaves are called naked, VERNATION.—The arrangement of the leaves in the bud has been denominated vernation (ver, spring), or prafoliation (pre, before, and folium, leaf), or gemmation (gemma, a bud). In considering vernation we must take into account both the manner in which each individual leaf is folded and also the arrangement of the leaves in relation to each other. These vary in different plants, but in each species they follow a regular law. The leaves in the bud are either placed simply in apposition, as in the Mistleto, or they are folded or rolled up longitudinally or laterally, giving rise to different kinds of vernation, as delineated in fig. 222 an, where the dot represents the axis and the folded or curved lines represent the leaves, the thickened part in- ‘dicating the midrib; figs. a and g being vertical sections ; b-f and h-n, horizontal. , The leaf taken individually is either folded longitudinally from apex to base (fig. 222 a), as in the Tulip-tree, and called reclinate or replicate; or rolled up in a circular manner from apex to base, as Fig. 210. Leaf-bud of Sycamore (Acer pseudo-platanus) covered with scales. 7, The branch. p, Pulvinus or swelling at the base of the leaf which has fallen, leaving a scar or cicatricula, c, in which the remains of three vascular bundles are seen, ee, Imbricated scales of the bud. Fig. 221, Transverse section of the same leaf-bud. ¢ eee, Thescales arranged in an imbricated manner, like the tiles on a house. /, The leaves folded ina plaited manner, exhibiting plicate vernation. Fig 220. Fig. 221. VERNATION OR PRASFOLIATION. 111 in Ferns (fig. 222 9), and called circinate (circino, I turn round) ; or folded laterally, conduplicate, as in Oak (fig. 222 6); or it has several folds like a fan, plicate or plaited, as in Vine and Sycamore (figs. 221 f, 222 c), and in leaves with radiating vernation, where the ribs mark the foldings ; or it is rolled upon itself, convolute or supervolute, as in Banana and Apricot (fig. 222 d); or its edges are rolled inwards, involute, as in Violet (fig. 222 ¢) ; or outwards, revolute, as in Rose- mary’ (fig. 222 f). The different divisions of a cut leaf may be folded or rolled up separately, as in Ferns, while the entire leaf may have either the same or a different kind of vernation. Other kinds of vernation receive their names from the arrange- ment of the leaves in the bud, taken as a whole. Leaves in the bud are opposite, alternate, or verticillate ; and thus different kinds of vernation are produced. Sometimes they are nearly in a circle at the same level, remaining flat, or only slightly convex externally, and placed so as to touch each other by their edges, thus giving rise to valvate vernation (fig. 222, h). At other times they are at different levels, and are applied over each other, so as to be imbricated, as in Lilac, and in the outer scales of Sycamore (figs. 220, 221); and occasionally the margin of one leaf overlaps that of another, while it, in its turn, is overlapped by a third, so as to be twisted, spiral, or con- tortive (fig. 2227). When leaves are applied to each other, face to face, without being folded or rolled together, they are appressed. When the leaves are more completely folded they either touch at their Fig. 222. Diagrams to show the different kinds of vernation. a-g, The folding of indi- vidual leaves ; a and g being vertical sections, b ¢ d e and f being horizontal. a, Reclinate or replicate. 6, Conduplicate. c¢, Plicate. d, Convolute. e, Involute. f, Revolute, g Circinate. h-n, Folding of leaves when united together in the leaf-bud. The sections are horizontal or transverse, and show the relative position of the leaves, and the mode in which each of them is folded. h, Valvate. 4, Twisted, spiral, or contortive. %, Opposite or accumbent, with the margins reduplicate. J, Induplicate. m, Equitant. mn, Obvolute or half-equitant, In all the figures the thickened portion indicates the midrib of the leaf and the dot marks the position of the axis, 112 i LEAF-BUDS AND BRANCHES. extremities and are accumbent or opposite (fig. 222 &), or are folded inwards by their margin, and become induplicate (fig. 222 1); ora conduplicate leaf covers another similarly folded, which in turn covers a third, and thus the vernation is equitané (riding), as in Privet (fig. 222 m); or conduplicate leaves are placed so that the half of the one covers the half of another, and thus they become halj- < equitant or obvolute, as in Sage (fig. 222 n). The scales of a bud sometimes exhibit one kind of vernation, and the leaves another (fig. 221). The same modes of arrangement occur in the flower-buds, as will be afterwards shown. ; Leaf-buds, as has been stated, are either terminal or lateral. By the production of the former (fig. 219 b¢), stems increase in length, while the latter (fig. 219 ba, ba, ba) give rise to branches, and add to the diameter of the stem. The terminal leaf-bud, after pro- ducing leaves, sometimes dies at the end of one season, and the whole plant, as in annuals, perishes ; or part of the axis is persistent, and remains for two or more years, each of the leaves before its decay producing a leaf-bud in its axil, This leaf-bud continues the growth in spring. In some trees of warm climates, as Cycas, Papaw-tree, Palms, and Tree ferns, the production of terminal buds is well seen. In these plants the elongation of the stem is generally regular and uniform, so that the age of the plant may be estimated by its height. Such stems (often endogenous) may thus be considered as formed by a series of terminal buds, placed one over the other. From this mode of growth they do not attain a great diameter (fig. 134, 1). In other trees, especially Exogens, besides the terminal bud there are also lateral ones. These, by their development, give rise to branches (rami), from which others, called branchlets or twigs (ramuli) arise. Such buds being always produced in the axil of leaves are of course arranged in a manner similar to the leaves. By the continual production of lateral leaf-buds, the stem of exogenous plants acquires a great diameter. Although provision is thus made for the regular formation of leaf-buds, there are often great irregularities in consequence of many being abortive, or remaining in a dormant state: Such buds are called latent, and are capable of being developed in cases where the terminal bud, or any of the branches, have been injured or destroyed. In some instances, as in Firs, the latent buds follow a regular system of alternation ; and in plants with opposite leaves, it frequently hap- pens that the bud in the axil of one of the leaves only is developed, and the different buds so produced are situated alternately on opposite sides of the stem. ' When the terminal bud is injured or arrested in its growth, the elongation of the main axis stops, and the lateral branches often acquire increased activity. By continually cutting off the terminal LEAF-BUDS AND BRANCHES. 113 buds, a woody plant is made to assume a bushy appearance, and thus pollard trees are produced. Pruning has the effect of checking the growth of terminal buds, and of causing lateral ones to push forth. The peculiar bird-nest appearance often presented by the branches of the common Birch depends on an arrestment in the terminal buds, a shortening of the internodes, and a consequent clustering or fascicula- tion of the twigs. In some plants there is a natural arrestment of the main axis after a certain time, giving rise to peculiar shortened stems. Thus the crown of the root (p. 46) is a stem of this nature, forming buds and roots. Such is also the case in the stem of Cyclamen, Testudinaria Elephantipes, and in the tuber of the potato. The pro- duction of lateral in place of terminal buds sometimes gives the stem a remarkable zigzag aspect. In many plants with a shortened axis, the lateral buds produce long branches. Thus the flagellum (flagellum, a whip or twig), or runner of the Strawberry and Ranunculus, is an elongated branch, developing buds as it runs along the ground ; the propagulum (pro- pago, a shoot), or offset, is a short thick branch produced laterally in fleshy plants from a shortened axis, and developing a bud at its ex- tremity, which is capable of living when detached, as in Houseleek, Fig. 223 repre- sents a strawberry plant, in which a’ is the primary axis, ending in a cluster of green leaves, 7, and some rudi- mentary leaves, f, and not elongating ; from the axil of ° one of the leaves proceeds a branch or runner, «”, with a rudimentary leaf, f’, about the Fig. 228. middle, and another cluster of leaves, f” and 1’, forming a young plant with roots; from this a third axis comes off, 7”, and so on. In many instances the runner decays, and the young plant assumes an independent existence. Gardeners imitate this in the propagation of plants by the process of layering, which consists in bending a twig, fixing the central part of it into the ground, and, after the production of adventitious roots, cutting off its connection with the parent. When the stem creeps along the surface of the ground, as in the Rhizome (fig. 107), or completely under ground, as in the Soboles Fig. 223, Flagellum or Runner of the Strawberry. a’, One axis which has produced a cluster of leaves, the upper, 7, green, the lower, f, rudimentary. From the axil of one of the latter a second axis, a”, arises, bearing about the middle a rudimentary leaf, /’, and a cluster of leaves, r, partly green and partly rudimentary, f’, at its extremity. From the axil of one of the leaves of this cluster a third axis, a, proceeds, I 114 AERIAL AND SUBTERRANEAN LEAF-BUDS. or creeping stem (fig. 108), the terminal bud continues to elongate year after year, thus making additions to the axis in a horizontal manner. At the same time buds are annually produced on one side which send shoots upwards and roots downwards. Thus, in fig. 108 (soboles of a Rush), 7 is the extremity of the axis or terminal bud, f e the leaves in the form of scales, p a the aerial shoots or branches, ¢ ¢ being the level of the ground. Again, in fig. 107 (rhizome of Solomon’s seal), a is the terminal bud which has been formed subsequently to 6, b the bud which has sent up leaves, and which has decayed, ¢ ¢ being the scars left by the similar buds of previous seasons. AERIAL AND SUBTERRANEAN LeEaF-BupDs.— According to the nature of the stems, leaf-buds are either aerial or subterranean; the former occurring in plants which have the stems above ground, the latter in those in which the stems are covered. In the case of Asparagus and other plants which have a perennial stem below ground, subterranean buds are annually produced, which appear above ground as shoots or branches covered with scales at first (fig. 129 J), and ultimately with true leaves, The young shoot is called a Turto (turio, a young branch). These branches are herbaceous and perish annually, while the true stem remains below ground ready to send up fresh shoots next season. In Bananas and Plantains, the apparent aerial stem is a shoot or leaf-bud sent up by an underground stem, and perishes after ripening fruit. In some plants several branches are sent up at once from the underground stem, in consequence of a rapid development of lateral as well as terminal buds ; and in such cases the lateral ones may be separated as distinct plants in the form of suckers (surculi). The potato is a thickened stem or branch capable of developing leaf-buds, which in their turn form aerial and subterranean branches, the former of which decay annually, while the latter remain as tubers to propagate the plant. Thus, in fig. 109, s's is the surface of the soil, p a is the aerial portion of the potato covered with leaves, tis the subterranean stem or tuber covered with small scales or pro- jections, as represented at T 6, from the axil of which leaf-buds are produced. This provision for a symmetrical development of axillary leaf-buds at once distinguishes the tuber of the potato from fleshy roots, like those of the Dahlia. Buisp.—A good example of a subterranean bud occurs in the Bulb, as seen in the Hyacinth, Lily, and Onion. This is a subterranean leaf-bud covered with scales, arising from a shortened axis. From the centre of the bulb a shoot or herbaceous axis is produced which dies down. New bulbs, or cloves, as they are called, are produced in the axil of the scales arising from the subterranean axis. At the base of the scales there is a flattened disc, varying in thickness, which is formed by the base of the buds, and which has sometimes been called the stem. The parts of the bulb are seen in fig. 224, where » marks the . SUBTERRANEAN LEAF-BUDS, BULB, AND CORM. 115 disc or round flat portion formed by the bases of the lateral buds from which the fasciculated roots, 7, proceed, e the scales or modified leaves, and f the true leaves. In the vertical section (fig. 225), b is the new bulb, formed like a bud in the axil of a scale. The new bulb some- times remains attached to the parent bulb, and sends up an axis and leaves ; at other times it is detached in the course of growth, and Fig. 295. Fig. 226. forms an independent plant. The new bulbs feed on the parent one, and ultimately cause its absorption. The scales are sometimes all fleshy, as in the scaly or naked bulb of the white lily (fig. 226 ¢ ¢ e), or the outer ones are thin and membranous, overlapping the internal fleshy ones, and forming a tunicated bulb, as in the Onion, Squill, Tulip, and Leek (fig. 224). The scales in bulbs vary in number. In Gagea there is only one scale ; in the Tulip and Fritillaria imperialis they vary from 2 to 5; while in Lilies and Hyacinths there are a great number of scales. In the Tulip a bud is formed in the axil of an outer scale, and this gives rise to a new flowering axis, and a new bulb, at the side of which the former bulb is attached in a withered state. In some Liliaceous plants the bulbs continue for two or more years. The bulb may bear on the same axis growths belonging to two seasons ; or it may bear numerous growths or shortened axes of several years. In the common hyacinth-there may be seen axes of four distinct generations on one bulb. The Corm (xogués, a stump) has already been noticed under Fig, 224. Tunicated bulb of Allium Porrum, or the Leek. 1, Roots. yp, A circular disc, or shortened stem intervening between the roots and the bulbous swelling. ee, Scales or subterranean modified leaves. jf, Upper leaves which become green. Fig, 225 Vertical section of the tunicated bulb of the Leek. The letters indicate the same parts as in the last figure. 0, Bud situated in the axil of a scale, which, by its development, forms a new bulb. Fig. 226. Scaly or naked bulb of Lilium album. 1, Roots. ¢¢ e, Scales or modified underground leaves. t, The flowering axis, cut. 116 ANOMALIES AND TRANSFORMATIONS OF LEAF-BUDS. the head of subterranean stems (p. 48, fig. 110). It may be considered as a bulb in which the central portion or axis is much enlarged, while the scales are reduced to thin membranes. Some have called it a solid bulb, A Corm may be generally distinguished from a Bulb by a transverse section of the latter presenting a series of circles, equal in number to the fleshy scales arranged around its central axis. It is seen in the Colchicum, Crocus, and Gladiolus. It produces either terminal buds, as in Gladiolus and Crocus, in which several annual additions to the corm remain attached together, and the newly pro- duced corms come gradually nearer and nearer to the surface of the soil ; or lateral buds, as in Colchicum, represented at fig. 110, where r indicates the roots, f the leaf, a’ the stem or axis of the preceding year withered, a’ the secondary axis, or the stem developed during the year, and taking the place of the old one, and which, in its turn, will give origin to a new axis, a’”, on the opposite side, according to the law of alternation. The new axes or corms being thus produced alternately at either side, there is very little change in the actual position of the plant from year to year. Bulbs and corms contain a store of starch and of other substances, for the nourishment of the young plants. ANOMALIES AND TRANSFORMATIONS OF Lzrar-Bups.—Leaf-buds arise from the medullary system of the plant, and in some instances they are found among the cellular tissue, without being in the axil of leaves. In this case they are extra-axillary, and have been called adventitious or abnormal, Such buds are produced after the stem and leaves have been formed, and in particular circumstances they are developed like normal buds. What have been called embryo-buds are woody nodules seen in the bark of the Beech, Elm, and other trees. They are looked upon as partially developed abnormal buds, in which the woody matter is pressed upon by the surrounding tissue, and thus acquires a very hard and firm texture. When a section is made, they present woody circles arranged around a central pith, and traversed by medullary rays (fig. 227). The nodules sometimes form imots on the surface of the stem, at other times they appear as large excrescences, and in some cases twigs and leaves are produced by them. Some consider embryo-buds as formed by layers of woody matter, which originate in the sap conveyed downward by the bark and cambium cells, and are deposited round a nucleus or central mass. Fig. 227, Fig. 227. Vertical section of a nodule, n, or embryo-bud embedded in the bark of the Cedar. It forms a projection on the surface. The woody layers form zones round a kind of pith. ANOMALIES AND TRANSFORMATIONS OF LEAF-BUDS. 117 r Leaf-buds sometimes become extra-axillary (fig. 228 6), in con- sequence of the non-appearance or abortion of one or more leaves, or on account of the adhesion of the young branch to the parent stem. In place of one leaf-bud, there are occasionally several accessory ones produced in the axil, giving origin to numerous branches (fig. 229 b). Fig. 298, Fig. 229, Such an occurrence is traced to the presence of latent or adventitious buds. Fig. 228 represents a branch, 7, of walnut, » the cut petiole, and 6 two buds, of which the upper is most developed ; while fig. 229 exhibits a branch of Lonicera tartarica, with numerous buds, 6, in the axil of the leaves, the lowest of which are most advanced. By the union of several such leaf-buds, branches are produced, having a thickened or flattened appearance, as is seen in the Fir, Ash, and other trees, These fasciated ( fascia, a band) branches, in some cases, however, are owing to the abnormal development of a single bud. In the axil of the leaves of Lilium bulbiferum, Dentaria bulbifera, and some other plants, small conical or rounded bodies are produced, called buwlbils or bulblets (fig. 230 666). They resemble bulbs in their aspect, and consist of a small number of thickened scales enclos- ing a growing point. These scales are frequently united closely together, so as to form a solid mass. Bulbils are there- fore ,transformed leaf-buds, which are easily detached, and are capable of pro- ducing young plants when placed in favourable circumstances, Occasionally leaf-buds are produced naturally on the edges of Fig. 228. Portion of a branch, 7, of the walnut, bearing the petiole, p, of a leaf which has been cut. In the axil of the leaf, several buds, 6, are produced, the highest of which are most developed. Fig. 229, Portion of a branch, 7, of Lonicera tartarica, bearing two opposite leaves, one of which has been cut, the other, f, being preserved. In the axil of the leaves clusters of buds, }, are seen, the lowest of which are most developed. Fig. 230. Portion of the stem of Lilium bulbiferum, with three alternate leaves, f/f, and three bulbils or bulblets, 6 b b, in their axils. 118 ANOMALIES AND TRANSFORMATIONS OF LEAF-BUDS. leaves, as in Bryophyllum calycinum and Malaxis paludosa (fig. 5a and on the surface of leaves, as in Ornithogalum thyrsoideum (fig. 232 These are capable of forming independent plants. Similar buds are also made to appear on the leaves of Gesnera, Gloxinia, and Achimenes, by wounding various parts of them, and placing them in moist soil ; this is the method often pursued by gardeners in their propagation. The Ipecacuan plant has been propagated by means of leaves inserted in the soil. In this case the lower end of the leaf becomes thickened like a corm, and from it roots are produced, and ultimately a bud and young plant, as shown in fig. 233. The cellular tissue near the surface of plants seems therefore to have the power of developing abnormal leaf- Fig. 231. Extremity of a leaf, 2, of Malaxis paludosa, the margin of which is covered with adventitious buds, 6b; thus becoming proliferous. Fig. 232. Portion of the blade of a leaf, f, of Ornithogalum thyrsoideum, on the surface of which are developed adventitious or abnormal buds, bbb, some of which are large. Fig. 233. Ipecacuan leaf, with petiole, annulated root, and young plant. a, Lamina or blade of leaf. , Petiole or leaf-stock. c, Swelling at the end of the petiole after being placed in the soil. d, Root proceeding from a oe showing an annulated form. e, Young plant arising from the swelling of the petiole. SPINES OR THORNS. - 119 buds in certain circumstances, Even roots, when long exposed to the air, may thus assume the functions of stems. Leaves bearing buds on their margin are called proliferous (proles, offspring, and fero, I bear). Sprnes or THoRNs. Branches are sometimes arrested in their development, and, in place of forming leaves, become trans- formed into spines and tendrils, Spines or thorns are undeveloped branches, ending in more or less pointed extremities, as in the Hawthorn. Plants which have spines in a wild state, as the Apple and Pear, often lose them when cultivated, in consequence of their being changed into branches ; in some cases, as in Prunus spinosa, or the Sloe (fig. 234), a branch bears leaves at its lower portions, and terminates in a spine. Leaves them- Fig. 234, Fig. 237. Fig. 238, Fig. 234, Branch of Prunus spinosa, or Sloe, with alternate leaves, and ending in a spine or thorn, Fig. 235. Pinnate leaf of Astragalus massiliensis, the midrib of which, 7, ends ina spine. s, Petiolary stipules. jf, Nine pairs of leaflets. Fig. 236. Branch of Berberis vulgaris, or Barberry, the leaves of which, fff, are transformed into branching spines, In the axil of each, a cluster, r 77, of regularly formed leaves is developed. Fig, 237. Base of the pinnate leaf of Robinia pseudacacia, the stipules of which, ss, are converted into spines or thorns. b, Branch. +, Petiole. Fig. 238, Branch of Ribes Uva-crispa, in which the pulvinus or swelling, ¢ cc, at the base of each of the leaves, fff, is changed into a spine, which is either simple, or double, or triple. 0 b, Leaf-buds arising from the axil of the leaves, 120 SPINES OR THORNS, AND TENDRILS. selves often become spiny by the hardening of their midrib or primary veins, and the diminution or absence of parenchyma, as in Astragalus massiliensis (fig. 235 r), where the midrib becomes spiny after the fall of some of the leaflets ; in the Holly, where all the veins are so; and in the Barberry (fig. 236), where some of the leaves, f f f, are produced in the form of spiny branches, with scarcely any paren- chyma. In place of producing a lamina or blade at its extremity, the petiole sometimes terminates inaspine. Stipules are occasionally trans- formed into spines, as in Robinia pseudacacia (fig. 237 s s), and such is also the case with the swelling or pulvinus at the base of the leaf, as in Ribes Uva-crispa (fig. 238 ce c). Branches are sometimes arrested in their progress at an early stage of their development, and do not appear beyond the surface of the stem ; at other times, after having grown to a considerable size, they undergo decay. In both instances the lower part of the branch becomes embedded and hardened among the woody layers of the stem, and forms a knot. TEnpDRits.—A leaf-bud is sometimes developed as a slender spiral or twisted branch, called a tendrid or cirrus (cirrus, a curl). Tendrils have their homologues in various organs, such as stems, branches, leaves, stipules, buds, midribs, parts of the flower, etc. When tendrils occupy the place of leaves, and appear as a con- tinuation of the leaf-stalk, they are called petiolary, as in Lathyrus Aphaca, in which the stipules perform the func- tion of true leaves. In Flagellaria indica, Gloriosa superba, Anthericum cirrha- tum, and Albuca cirrhata, the midrib of the leaf ends ina tendril ; and in Vetches, the terminal leaflet, and some of the lateral ones at the extremity of their pinnate leaves, are changed, so as to form a branching tendril. In the Passion-flower the lateral buds are thus altered, Fig. 239. Portion of a branch of the Vine (Vitis vinifera). a’, First axis, terminated by a tendril or cirrus, v’, which assumes a lateral position, and bears a leaf, f’, From the axil of this leaf a second axis, a”, comes off, which seems to be a continuation of the first, and is terminated also by a tendril, v’, bearing a leaf, f”. From the axil of this second leafa third axis, a”, arises, terminated by a tendril, v’”, and bearing a leaf, f’”, from the axil of which a fourth axis, a’”, arises. Fig. 239. TENDRIL OR CIRRUS. 121 with the view of enabling the plant to climb. In the Vine the tendrils are looked upon as the terminations of separate axes, or as transformed terminal buds, and are sometimes called sarmenta. In the Vine there are no young buds seen in the angle between the stem and leaves, nor between the stem and tendrils ; and the latter are not axillary. Fig. 239 represents the branch of a Vine, in which @ is the primary or first formed axis, ending in v’, a tendril or altered terminal bud, and having a leaf, f’,on one side. Between this leaf and the tendril, which repre- sents the axis, a leaf-bud was formed at an early date, producing the secondary axis, or branch, a", ending in a tendril, v", with a lateral leaf, f', from which a tertiary axis or branch, a”, was developed, ending in a tendril v”, and so on, The tendrils of Ampelopsis Veitchii are termi- nated by discs which secrete a sticky matter, by means of which they adhere to walls, etc. The tendrils, like those of the Vine, are modi- fications of the axis. Tendrils twist in a spiral manner, and enable the plants to rise into the air by twining round other plants. The direction of the spiral frequently differs from that of the climbing stem which produces the tendril. In the Vine, the lower part of the stem is strong, and needs no additional support ; the tendrils therefore occur only in the upper part, where the branches are soft, and require aid to enable them to support the clusters of fruit. In the vanille plant. (Vanilla aromatica) the tendrils are produced opposite the leaves, until the plant gains the top of the trees by which it is supported ; the upper tendrils being then developed as leaves. The midrib is sometimes prolonged in a cup-like or funnel-shaped form ; this is occasionally seen in the common cabbage, and seems to depend on the vascular bundles of the midrib spreading out at their extremity in a radiating manner, and becoming covered with parenchyma in such a way as to form a hollow cavity in the centre. Special Functions of Leaves, Leaves expose the fluids of plants to the influence of air and light, The fluids so exposed are elaborated, and thus fitted for the formation of the various vegetable tissues and secretions. For the proper performance of this function the structure of the leaves and their arrangement on the stem and branches, renders them well adapted. A plant, if constantly stripped of its leaves, is destroyed, from non-development of tissue and absence of secretions. On this principle, weeds, with creeping stems and vigorous roots, which are with difficulty eradicated, may be killed. The elaboration of fluids in the leaves necessarily implies interchange of their constituents with those of the surrounding atmosphere ; hence two processes are inevi- table—a passing inwards into the leaf of the atmospheric elements 122 FUNCTIONS OF LEAVES. by a process of absorption, and an outward current of the components of the plant-juices by a process of exhalation, In the cells of the leaves changes take place under the agency of light, by which oxygen is given off and carbon fixed. These will be considered under the head of vegetable respiration. The absorption of carbonic acid and of fluids is carried on by the leaves, chiefly through their stomata, and most rapidly by the under surface of ordinary leaves in which the cuticle is thinnest, the cellular tissue least condensed, and stomata most abundant; the upper surface of the leaf, which usually pre- sents a polished and dense epidermis, with few stomata, taking little part in such a process. Hoffman has ascertained that leaves absorb fluids in large quantities ; that during a fall of rain the vegetable fluids undergo from such a cause a process of dilution, leading to an immediate and more rapid descent of sap, which under such circum- stances is capable of general diffusion throughout the several vege- table tissues. Some physiologists have expressed doubts as to absorp- tion being carried on by the leaves in ordinary circumstances. Leaves also absorb gaseous matters, Saussure states that oxygen is absorbed by the leaves during night, the quantity varying according to the nature of the plant. . Boussingault found that the leaves of the Vine absorbed carbonic acid from the air. Other experiments prove that ammonia and nitrogen are similarly acted on. Leaves also give off gases and liquids by a process of exhalation or transpiration. A moderate amount of carbonic acid is exhaled during darkness, and a large quantity of liquid is given off by tran- spiration. The number and size of the stomata regulate the transpi- ration of fluids, and it is modified by the nature of the epidermis. The absorbing power of leaves depending on similar causes, is capable of being increased by any process which removes either natural or imposed obstructions to the free action of their surface. It is thus that rain, while supplying the material for absorption, at the same time renders the leaf more capable of such action. In plants with a thick and hard epidermal covering, exhalation is less vigorous than in those where it is thin and soft. Some succulent plants of warm climates have a very thick covering. The peculiar character of the phyllodia of Australian plants is probably connected with the dry nature of the climate. The process of transpiration is more under the influence of light than of heat. It assists the process of endosmose, by rendering the fluid in the cells thicker, and thus promotes the circulation of sap. The quantity of fluid exhaled varies in amount in different plants. A Sunflower three feet high gave off twenty ounces of watery fluid daily. Hales found that a Cabbage, with a surface of 2736 square inches, transpired on an average nineteen ounces per day; a Vine, of 1820 square inches, from five to six ounces. Deheran found that EXHALATION OR TRANSPIRATION. 123 large leaves of Colza evolved in an hour from one to two per cent of their weight of water. Experiments have shown that the mean amount of water contained in the leaves of the Cherry’ Laurel is 63-4 per cent, and of this only about 6 per cent could be easily removed by sulphuric acid or chloride of calcium, In the sun leaves transpire most in a saturated atmosphere. In the shade transpiration ceases when the atmosphere is loaded with watery vapour. Experiments on exhalation may be made by taking a fresh leaf with a long petiole, putting it through a hole in a card which it exactly fits, and applying the card firmly and closely to a glass tumbler, about two-thirds full of water, so that the petiole is inserted into the water, then inverting an empty tumbler over the leaf, and exposing the whole to the sun, the fluid exhaled will be seen on the inside of the upper tumbler. The ex- periment may be varied by putting the apparatus in darkness, when little or no exhalation takes place, or in diffuse daylight, when it is less than in the sun’s rays. This process of exhalation imparts moisture to the atmosphere, and hence the difference between the air of a wooded country and that of a country deprived of forests. The cells in the lower side of a leaf where stomata exist are chiefly concerned in the aeration of the sap, whilst other assimilative processes go on in the upper cells. Leaves, after performing their functions for a certain time, wither and die. In doing so, they frequently change colour, and hence arise the beautiful and varied tints of the autumnal foliage. This change of colour is chiefly occasioned by the diminished circulation in the leaves, and the higher degree of oxidation to which their chlorophyll has been submitted. Leaves which are articulated with the stem, as in the Walnut and Horse-chestnut, fall and leave a scar, while those which are continuous with it remain attached for some time after they have lost their vitality, as in the Beech. Most of the trees of this country have deciduous leaves, their duration not extending over more than a few months ; while in trees of warm climates, the leaves often remain for two or more years. In tropical countries, however, many trees lose their leaves in the dry season. This is seen in the forests of Brazil, called Catingas, The period of defoliation varies in different countries according to the nature of their climate. Trees which are called evergreen, as Pines and Evergreen-oak, are always deprived of a certain number of leaves at intervals, sufficient being left, however, to preserve their green fappearance. Various causes - have been assigned for the fall of the leaf. In cold climates, the deficiency of light and heat in winter causes a cessation in the functions of the cells of the leaf ; its fluids disappear by evaporation ; its cells and vessels become contracted and diminished in their calibre ; various inorganic matters accumulate in the texture ; the whole leaf becomes drys; its parts lose their adherence ; a process of disjunction 124 FUNCTIONS OF NUTRITIVE ORGANS. takes place by a folding inwards of the tissue at the point where the leaf joins the stem or branch, and this gradually extends ; complete separation then takes place, and the leaf either falls by its own weight or is detached by the wind. In warm climates the dry season gives rise to similar phenomena. Section IL.—GeENERAL VIEW OF THE FUNCTIONS OF THE NutTRITIVE ORGANS. In order. that plants may be nourished, food is required. This food, in a crude state, enters the roots by a process of absorption or imbibi- tion; it is then transmitted from one part of the plant to another, by means of the circulation or progressive movement of the sap ; it reaches the leaves, and is there submitted to the action of light and air, which constitutes the function of respiration ; and thus the fluids are finally fitted for the process of assimilation, and form various vegetable products and secretions, 1.—Food of Plants and Sources whence they derive their Nourishment. Chemical Composition of Plants, The nutriment of plants can’ only be ascertained when their chemical composition has been determined. The physiologist and chemist must unite in this inquiry, in order to arrive at satisfactory conclusions. Much has been done by chemists to aid the botanist in his investigations, and to place physiological science on a sound and firm basis. It is true that many processes take place in plants which cannot as yet be explained by the chemist, and to these the name of vital has been applied. This term, however, must be considered as implying nothing more than that the function so called occurs in living bodies, and in the present state of our knowledge cannot be fully explained by chemical or physical laws. A greater advance in science may clear up many difficulties in regard to some of the vital functions, while others may ever remain obscure. Plants are composed of certain chemical elements, which are com- bined in various ways, to form organic and inorganic compounds. The former are composed of carbon, oxygen, hydrogen, and nitrogen or azote, with a certain proportion of sulphur and phosphorus ; while the latter consist of various metals, combined with oxygen, other metal- loids, and acids. In all plants there is a greater or less proportion of water, the quantity of which is ascertained by drying at a temper- ature a little above that of boiling water. By burning the dried plant the organic constituents disappear, and the inorganic part is left in CHEMICAL COMPOSITION OF PLANTS. 125 the form of ash. The relative proportion of these constituents varies in different species, as seen in the following table by Solly, in which the proportions are given in 10,000 parts of the fresh plants :-— Water. Organic Matter. Inorganic. Potato. 5 “ . 7718 tes 2173 A 114 Turnip. ‘ , . 9308 its 588 sath 104 Sea Kale . 2 . 9238 ase 705 see 57 French Beans . . - 9317 ees 619 Ha 64 Red Beet . 2 ¥ . 8501 ile 1390 aa, 109 Asparagus : ; . 9210 ae 735 oe 55 Water Cress. ‘ . 9260 es 633 vei 107 Sorrel . : ‘ - 9207 ae 702 ae 91 Parsley . : : . 8430 sae 1299 sd 271 Fennel . j . . 8761 ee 1048 an 191 ‘Salsafy . 7 . 7951 is 1929 le 120 Mustard 2 . - 9462 eA 436 se 102 An analysis of 100 parts of Fruits gives the following results :— Water. Organic. - Inorganic. Strawberry . , « 90°22 eis 9°37 = 0°41 Green Gage, whole fruit. 83°77 ses 15°83 ee 0°40 Cherry, do. . 82°48 is 17°09 i 0.43 Pear, do. » 82°55 oie 16°04 00 0°41 Apple, do. » 84-01 as 15°72 ee 0:27 Gooseberry . 7 - 90°26 ee 9°35 mae 0°39 The following table, by Johnston, represents the constituents in 1000 parts of plants and seeds, dried at 230° Fahrenheit, and in the state in which they are given to cattle; the organic matter being indicated by the carbon, oxygen, hydrogen, and nitrogen ; the inorganic by the ash :— Wheat. Oats. Peas. Hay. Turnips. Potatoes. Carbon . . 455 ... 507... 465 ... 458 2. 429 2. 441 Hydrogen Bh wee 64 we 61 wg, 50 eee BG es. 58 Oxygen. . 4380 ... 867 ... 401 ... 887... 422 ... 439 Nitrogn * . 385 .. 22 .. 42 2. 15 .. 17 1. 12 Ash. © BB ac, “AO a, BI as “90 ex 26 sex. 50 By the process of drying, the 1000 parts of these substances lost water in the following proportions :— Wheat 166 vie Peas 86 si Turnips 925 Oats 151 ae Hay 158 Sod Potatoes 722 As plants have no power of locomotion, it follows that their food must be universally distributed. The atmosphere and the soil ac- cordingly contain all the materials requisite for their nutrition. These materials must be supplied either in a gaseous or a liquid form, and hence the necessity for the various changes which are constantly going on in the soil, and which are aided by the efforts of man, Plants are capable of deriving all their nourishment from the mineral kingdom. 126 ORGANIC CONSTITUENTS OF PLANTS. The first created plants in all probability did so, but in the present day the decaying remains of other plants and of animals are also con- cerned in the support of vegetation. Organic Constituents and their Sources. Caron (C) is the most abundant element in plants. It forms from 40 to 50 per cent of all the plants usually cultivated for food. When plants are charred the carbon is left, and as it enters into all the tissues, although the weight of the plants is diminished by the process, their form still remains. When converted into coal (a form of carbon), plants are frequently so much altered by pressure as to lose their structure, but occasionally it can be detected under the microscope. Carbon is insoluble, and therefore cannot be absorbed in its uncombined state. When united with oxygen, however, in the form of carbonic acid, it is readily taken up either in its gaseous state by the leaves, or in combination with water by the roots. The humus or vegetable mould in the soil contains carbon, and in soils of a peaty nature it exists in very large quantity. The carbon in the soil is converted into carbonic acid in order to be made available for the purpose of plant-growth. Carbon has the power of absorbing gases, and in this way, by enabling certain combinations to go on, it assists in the nourishment of plants. In the atmosphere, carbonic acid is always present, averaging about zs'cv part, arising from the respiration of man and animals, combustion, and other processes. A certain atmospheric equilibrium is thus maintained, consequent on the dif ference between vegetable and animal respiration, the latter giving out carbonic acid, which the former consumes. OxyceEn (QO) enters into the composition of all plants, but never in quantity sufficient to convert all the hydrogen and carbon present in the plant into water and carbonic acid. In the ash of plants, oxygen, next to carbon, is the most abundant constituent. Oxygen in the air amounts to about 20°9 per cent, and it forms $ by weight of water. Combined with various elements it forms a great part of the soil and solid crust of the earth. It is chiefly in its state of combina- tion with hydrogen to form water (H,O) that oxygen is taken up by plants, but also as carbonic acid (CO,) and oxysalts. Hyprocen (H) is not found in a free state in nature, and with the exception of coal, it does not enter into the composition of the - mineral masses of the globe. It forms + by weight of water, and it is present in the atmosphere in combination with nitrogen. It is also found in the air united with sulphur (8) and carbon, as a product of vegetable decay. It is mostly from the decomposition of water by the combined action of chlorophyll and sunlight that plants obtain their supply of hydrogen. ‘ ‘ ORGANIC CONSTITUENTS OF PLANTS. 127 Nirrocen (N) is another element found in plants. It forms 79:1 per cent of the atmosphere, and abounds in animal tissues. It is therefore requisite for the purposes of animal life that nitrogen be furnished in food. Those vegetables containing the greatest quantity of nitrogenous matter are the most nutritive. Animal matters, during their decay, give off nitrogen, combined with hydrogen, in the form of ammonia (NHs), which is absorbed in large quantities by carbon, is very soluble in water, and seems to be the chief source whence plants derive nitrogen. In tropical countries where thunderstorms are frequent, the nitrogen and oxygen of the air are sometimes made to combine, so as to produce nitric acid (N2O;), which, either in this state, or in combination with alkaline matters, furnishes a supply of nitrogen. Daubeny thinks that the ammonia and carbonic acid in the atmosphere are derived in part from volcanic actions going on in the interior of the globe. The continued fertility of the Terra del Lavoro, and other parts of Italy, is attributed by him to the disengage- ment of ammoniacal salts and carbonic acid by volcanic processes going on underneath ; and to the same source he traces the abundance of glutin in the crops, as evidenced by the excellence of Italian macaroni, Miilder maintains that the ammonia is not carried down from the atmosphere, but is produced in the soil by the combination between the nitrogen of the air and the hydrogen of decomposing matters. The same thing takes place, as in the natural saltpetre caverns of Ceylon, with this exception, that, by the subsequent action of oxygen, ulmic, humic, geic, apocrenic, and crenic acids, are formed, in place of nitric acid. These acids consist of carbon, oxygen, and hydrogen, in different proportions, and they form soluble salts with ammonia. By all porous substances, like the soil, ammonia is pro- duced, provided they are moist, and filled with atmospheric air, and are exposed to a certain temperature. It is thus, he states, that moist charcoal and humus become impregnated with ammonia, . These four elementary bodies then are supplied to plants, chiefly in the form of carbonic acid (OO2), water (H.O), and ammonia (NH,). In these states of combination they exist in the atmosphere, and hence some plants can live suspended in the air without any attach- ment to the soil. When a volcano or a coral island appears above the waters of the ocean, the lichens which are developed on it are nourished in a great measure by the atmosphere, although they sub- sequently derive inorganic matter from the rocks, to which they are attached. Air plants, as Bromelias, Tillandsias, some Orchidacee, and many species of Ficus, can grow for a long time in the air. In the Botanic Garden of Edinburgh a specimen of Ficus australis lived in this condition for upwards of twenty years, receiving no supply of nourishment except that afforded by the atmosphere and 128 INORGANIC CONSTITUENTS OF PLANTS. common rain water, containing, of course, a certain quantity of in- organic matter. The elementary bodies already mentioned, in various states of combination, constitute the great bulk of plants. They occur in the form of binary compounds, as water and oily matters ; ternary, as starch, gum, sugar, and cellulose; quaternary, as glutin, albumin, casein, and fibrin. The latter compounds seem to require for their composition not merely the elements already noticed, in the form of a basis, called Protein, but certain proportions of sulphur and phosphorus in addition ; thus, albumin = 10 Pr. + 1 P + 28; fibrin = 10 Pr. +1P +15; casein = 10 Pr. +158. The tissues, into the com- position of which these protein compounds enter, are tinged of a deep orange-yellow by strong nitric acid. These compounds are highly important in an agricultural point of view, and the consideration of them will be resumed when treating of the application of manures. Inorganic Constituents and their Sources, The consideration of the inorganic constituents of plants is no less important than the study of their organic elements. The organic. substances formed by plants are decomposed by a moderately high temperature ; they easily undergo putrefaction, especially. when ex- posed to a moist and warm atmosphere, and few of them have been formed by human art. Their inorganic constituents, on the other hand, are not so easily decomposed ; they do not undergo putrefaction, and they have been formed artificially by the chemist. The organic part of plants, even in a dried state, forms from 88 to 99 per cent of their whole weight. Consequently, the ash or inorganic matter constitutes a very small proportion of the vegetable tissue. It is not, however, on this account to be neglected, for it is found to be of great importance in the economy of vegetation, not merely on account of its entering directly into the constitution of various organs, but also from assisting in the production of certain organic compounds. Some of the lower tribes of cellular plants can exist apparently without any inorganic matter. Thus Miilder could not detect a particle of ash in Mycoderma vini, nor in moulds pro- duced in large quantity by milk sugar. Deficiency of inorganic matter, however, in general injures the vigour of plants, and it will be found that, in an agricultural point of view, this requires par- ticular attention—a distinct relation subsisting between the kind and quality of the crop, and the nature and chemical composition of the soil in which it grows. It has been shown, by careful and repeated experiments, that when a plant is healthy and fairly ripens its seeds, the quantity and quality of the ash is nearly the same in whatever soil it is grown; and that, when two different species are grown in INORGANIC CONSTITUENTS OF PLANTS. 129 the same soil, the quantity and quality of the ash varies—the dif- ference being greater the more remote the natural affinities of the plants are. The following are the inorganic elements of plants and their combinations :— Chlorine (Cl.) combined with metals forming chlorides. Iodine (I.) woe) MOtals iodides. Bromine (Br.) wove =6 Metals... bromides, we wee (Metals. sulphides, : sulphuretted hydrogen, or Sulphur (S.) whe hydrogen ... oe 2 ag se ORY ae, sulphuric acid. Phosphorus (P.) we ow. «Oxygen, phosphoric acid, A ia Ate, COXYBOD: sie potash. Potacsmien (i) .» s. Chlorine ... chloride of potassium. we owe) OXYGEN, soda. Sodium (Na.) } :.. @hlevivie chloride of sodium. av (common salt.) ‘ oxygen... lime. cplernen(e) vos. chlorine... chloride of calcium. Magnesium (Mg.) wo... oxygen... -magnesia, Aluminum (Al.) we wee) OKYGEN alumina. Silica (Si.) ee. ORYEED ss silica. Tron (Fe.) et oxides Manganese (Mn.) aoe a and. Copper (Cu.) P sulphides. To these we may add Fluorine (F), the presence of which in plants has been recently noticed. The extraordinary attraction of this element for Silica renders it a matter of impossibility to procure it in a separate state for examination. It is found in those vegetable structures in which Silica abounds, as in the stems of the Graminez and Equisetacez. , The quantity of inorganic matter or ash left by plants varies in different species, and in different parts of the same plant. The dried leaves usually contain a large quantity. Saussure found that— Dried bark of Oak oe i : 60 parts of ash in 1000 Dried leaves ‘ - 53 bis ht Dried alburnum r , ‘ é 4 Dried duramen ; - . 2 2 The dried leaves of Elm contain more than 11 per cent of inorganic matter, while the wood contains less than 2 per cent; the leaves of the Willow, 8 per cent, wood, 0°45 ; leaves of Beech, 6°69, wood, 0°36 ; leaves of Pitch- -pine, 3: 5, wood 0:25. Thus, the decaying leaves of trees restore a large quantity of inorganic matter to the soil. The following tables show the relative proportion of inorganic compounds present in the ash of plants :— K 130 INORGANIC CONSTITUENTS OF PLANTS. According to Sprengel, 1000 Ibs. of wheat leave 11°77 Ibs., and of wheat straw 35°18 lbs. of ash, consisting of— Grain. Straw. Potash ‘ : ‘ fi i 2°25 bai 0°20 Soda . : 5 ‘ ‘ : 2°40 Sts 0:29 Lime . ‘ : : : 5 0:96 re 2°40 Magnesia. : : . F 0°90 as 0°32 Alumina with trace of Iron. i 0°26 es 0°90 Silica. i 3 . z i 4:00 ae 28°70 Sulphuric acid 5 * 7 0°50 ws 0°37 Phosphoric acid. & : é 0-40 ee 1°70 Chlorine - 3 r ‘i z 0°10 wi 0°30 11°77 lbs. 35°18 lbs. In 1000 Ibs. of the grain of the Oat are contained 25°80 Ibs., and of the dry straw 57°40 lbs. of inorganic matter, consisting of— Grain. Straw. Potash f , 3 ¢ : 1°50 ok 8°70 Soda . . ‘ , r ‘ 1°32 oe 0°02 Lime . - z ‘ 4 : 0°86 ies 1°52 Magnesia. 2 z : é 0°67 see 0:22 Alumina ss : : 7 A 0-14 isis 0°06 Oxide of Iron 5 5 ‘ « 0°40 is 0°02 Oxide of Manganese . ‘ . 0°00 ss 0:02 Silica . , 3 3 2 . 19°76 — 45°88 Sulphuric acid i 3 a 7 0°35 ie 0°79 Phosphoric acid. : . 5 0°70 Set 0°12 Chlorine , , ‘ Fi : 0-10 ae 0°05 25°80 lbs. 57°40 Ibs. In 1000 Ibs, of the field Bean, field Pea, and Rye-grass hay, after being dried in the air, the following is the amount of ash, and its composition :— Field Bean. Field Pea. Rye-grass. Seed. Straw. Seed. Straw. Hay. Potash 7 : » 415 1656 ... 810 2°35 .. 8°81 Soda fi a » 816 050 ... 7°89 — .« 38°94 Lime ‘ » 165 6:24 ... 0°58 27:30 ... 7:34 Magnesia ‘i é » 158 2:09 ... 1°36 3°42 ... 0°90 Alumina . é . 0384 O10 .. 020 0°60 ... 0°31 Oxide of Iron. . — 007 ... O10 0:20 _— Oxide of Manganese . — 0°05 — 007 «. — Silica & » 1:26 220 ... 410 9°96 ... 27°72 Sulphuric acid. » 089 034 ... 0°53 3°37 ... 3°58 Phosphoric acid . » 292 2:96 ... 1°90 2°40 ... 0°25 Chlorine. , » O41 0°80 ... 0°38 0°04 ... 0°06 21°36 31°21 24°64 49°71 52°86 Dr. R. D. Thomson gives the following analysis of the inorganic matter in the stem and seeds of Lolium perenne :— INORGANIC CONSTITUENTS OF PLANTS. 131 Stem. Seed. Silica . . : é ‘ . 64°57 ie 42-28 Phosphoric acid. . ‘ 7 » 12°51 wes 18°89 Sulphuric acid =. : : 7 — wee 3°12 Chlorine ‘ ‘ 5 fs —_ sii trace. Carbonic acid é f 7 ° _— sas 3°61 Magnesia. ' é : ‘ 4:01 a 5°31 Lime . : ey bs } 6°50 Fis 18°55 Peroxide of Tron ; . ‘ : 0°36 wwe 2°10 Potash . ; « 7 j ‘ 8°03 wee 4°80 Soda . : A ‘ a . 2°17 ia 1°38 These inorganic elements are variously combined in plants, in the form of sulphates, phosphates, silicates, and chlorides. Some plants, as Wheat, Oats, Barley, and Rye, contain a large quantity of Silica in their straw ; others, such as Tobacco, Pea-straw, Meadow-clover, Potato-haulm, and Sainfoin, contain much lime ; while Turnips, Beet- root, Potatoes, Jerusalem-artichoke, and Maize-straw, have a large proportion of salts of potash in their composition. Sulphates and phosphates are required to supply part of the material necessary for the composition of the nutritive protein compounds found in grain. Sizica (SiO,) abounds in Grasses, in Equisetum, and other plants, giving firmness to their stems. The quantity contained in the Bamboo is very large, and it is occasionally found in the joints in the form of Tabasheer. Reeds, from the quantity of siliceous matter they contain, are said to have caused conflagrations, by striking against each other during hurricanes in warm climates. In species of Equisetum, the silica in the ash is as follows :— Ash. Silica. Equisetum arvense 5 ‘ : 13°84 wis 6°38 limosum. if 15°50 aa 6°50 hyemale ‘ ‘ 11°81 gis 8°75 maximum . ‘ ‘ 23°61 na 12°00 The third of these furnishes Dutch Reed, used for polishing mahogany. The silica is deposited in a regular manner, forming an integral part of the structure of the plant. Many insoluble matters, as silica, seem to be deposited in cells by a process of decomposition ; thus, silicate of potash in a vegetable sap may combine with oxalic acid, by which oxalate of potash and silicic acid will be produced, as in the cells of Grasses and Equisetum. Chara translucens has a covering of silicic acid, while CO. vulgaris has one composed of silicic acid and carbonate of lime ; and Chara hispida has a covering of carbonate of lime alone. Silica, the only known oxide of Silicon, contains 28 parts silicon, and * 32 parts oxygen. It is in reality an acid, though a very weak one at ordinary temperatures. Its insolubility in water prevents the mani- festation of its acid properties under ordinary circumstances. In those plants in which silica most abounds, Fluorine has also been discovered. 132 INORGANIC CONSTITUENTS OF PLANTS. The test for the presence of the latter rests in acting on the fluoride with concentrated sulphuric acid, and so producing hydrofluoric acid, which possesses the property of etching glass ; the glass being coated with wax, and the design to be etched traced with a pointed instru- ment. _ Lime is found in all plants, and in some it exists in large quantity. It occurs sometimes in the form of carbonate on the surface of plants, Thus, many of the Characese have a calcareous encrustation. The crystals or raphides (p. 10), found in the cells of plants, have lime in their composition. In the roots of Turkey and East India Rhubarb the crystals of oxalate of lime have been estimated at about 25 per cent, while in those of the English plant the proportion is about 10 per cent. In the Cactus tribe crystals of the same kind have been observed, the presence of which, in excessive quantity, imparts brittle- ness to the stem of the old plant. Sopa AND PorasH occur abundantly in plants. They are taken up from the soil in combination with acids. Those growing near the sea have a large proportion of soda in their composition, while those growing inland contain more potash. Various species of Salsola, Salicornia, Halimocnemum, and Kochia, yield soda for commercial purposes, and are called Halophytes (@As, salt, and girov, plant). The young plants furnish more soda than the old ones. There are certain species, as Armeria maritima, Cochlearia officinalis, Plantago maritima, and Silene maritima, which are found both on the sea- shore and high on the mountains removed from the sea. In the former situation they contain much soda and some iodine; while in the latter, potash prevails, and iodine disappears. Inon, Mancanese, and Copper, especially the two latter, exist in small quantity in plants. Iron exists in the soil either as an oxide, sulphide, or carbonate, usually occurring as peroxide. Iron when held in solution as carbonate is capable of being absorbed into the vegetable tissues. ' Copper has been detected in coffee. All these inorganic matters are derived in a state of solution from the soil, and plants are said to have, as it were, a power of selection, certain matters being taken up by their roots in preference to others. Saussure made a series of experiments on this subject, and stated that when the roots of plants were put into solutions containing various saline matters in equal proportions, some substances were taken up by imbibition in larger proportion than others. Bouchardat doubts the accuracy of Saussure’s conclusions on this point. He thinks that errors arose from the excretions of the plants and other causes. He performed similar experiments with plants of Mint, which had been growing for six months in water previous to experi- ment, and he found that in watery solutions of mixed salts the plant ‘absorbed all in equal proportions. Daubeny states, that if any par- ROTATION OF CROPS. 133 ticular salt is not present, the plant frequently takes up an isomor- phous one. The differences in the absorption of solutions depend, perhaps, on the relative densities alone, and not on any peculiar selecting power in roots, for it is well known that poisonous matters are absorbed as well as those which are wholesome. The following experiments show that poisonous matters in solution, varying from half a grain to five grains in the ounce of water, are taken up by roots, and that some substances which are poisonous to animals do not appear to act energetically upon plants :— Growing Plants. Zincic chloride i on beans Zincic sulphate Zi . cabbages and wheat Cupric sulphate . . beans Cupric nitrate s . beans 7 Cupric acetate . . cabbages quickly destroyed. beans Mercuric chloride 4 wheat cabbages -Arsenious acid : . cabbages and wheat weak solutions did not de- Potassic arseniate . . barley and cabbages stroy. Plumbic acetate . . beans destroyed in a few days. Potassic bichromate . cabbages, beans, barley eo males: ‘nwo. tt Paes ae . beans destroyed in a few days. Baric chloride i . beans . Baric nitrate . . . cabbages and wheat qunclely destenyed: Strontic nitrate . . beans Se tinless 80: Calcic chloride, sul- beana improved when very di- phate, and nitrate : luted. Magnesic chloride and injured, and if strong de- sulphate beans and cabbages stroyed. Sodic phosphate . . beans and cabbages see ; Sodic chloride : . beans and cabbages no injury when diluted. Rotation or Crops.—As the inorganic materials which enter into the composition of plants vary much in their nature and relative proportions, it is evident that a soil may contain those necessary for the growth of certain species, while it may be deficient in those re- quired by others. It is on this principle that the rotation of crops is founded; those plants succeeding each other in rotation which require different inorganic compounds for their growth. In ordinary cases, except in the case of very fertile virgin soil, a crop if grown for several years in succession in the same field will deteriorate in a marked degree. This has been tested by growing plants on the same and on different plots in successive years, with the following results :— 134 COMPOSITION OF SOILS. Average of 5 years. in the same plot : F : : 72:9 lbs. tubers. Eetelors | in different plot: , 4 : 9228) har os Flax same A ‘ 7 : . 15°0 Ibs, different : ¥ : ‘ ue same F é ‘ : ‘ ‘ : Beans - ) different bk a) ae ot 84'3 same 3 > 3 ‘ ‘ ; Barley -jdifferent. . . 3 . - i865 2 same : = 5 : 5 ‘| Taemips different . ‘ 3 i r ‘ pee \ same 5 ‘ < m : : : Oats different . 5 ; 7 ‘ 7 32:4 This shows a manifest advantage in shifting crops, varying from 1 to 75 per cent ; the deficiency of inorganic matter being the chief cause of difference. As this matter is of great importance to plants, it follows that the composition of soil requires special notice. CHEMICAL CoMPOSITION oF SoILs. Soils have been divided according to the proportion of clay, sand, and lime, which they possess, into— 1. Argillaceous soils, possessing little or no calcareous matter, and above 50 per cent of clay. . Loamy soils, containing from 20 to 50 per cent of clay. . Sandy soils, not more than 10 per cent of clay. . Marly soils, 5 to 20 per cent of calcareous matter. . Calcareous soils, more than 20 per cent of carbonate of lime. Humus soils, in which vegetable mould abounds. Ov O9 bo Below the superficial soil there exists what is called subsoil, which varies in its composition, and often differs much from that on the surface. Into it- the rain carries down various soluble inorganic matters, which, when brought to the surface by agricultural opera- tions, as trenching and subsoil ploughing, may {materially promote the growth of crops. The advantages of subsoil ploughing are dependent on the nature of the soil, By means of it the subsoil is loosened, so as to be easily acted upon by air and water, and the efficiency of the drainage is increased, It is not fitted for all soils, and in some instances it may do harm. A knowledge of the chemical as well as mechanical nature of soils guides the agriculturist to a certain extent in his operations ; since, by the judicious application of manures, certain deficiencies may be supplied, and, by admixture, soils may be rendered more suitable for the purposes of vegetation. Humvs, or decaying woody fibre, called also ulmine, or coal of humus, exists in soils. It is soluble in alkalies, yielding a brown solution, which, when treated with an acid, produces a brown pre- cipitate, said to contain humic, ulmic, and geic acids ; but the separate yal COMPOSITION OF SOILS. 135 existence of these compounds as definite acids is somewhat doubtful. Humus absorbs ammonia, and it is slowly acted upon by the atmo- sphere, so as to form carbonic acid by combination with oxygen. Peaty soils contain much of this substance. When peroxide of iron is present in such soils it loses part of its oxygen, and is converted into the protoxide. Sinica, in greater or less quantity, is found in all soils; but it abounds in sandy soils. In its ordinary state it is insoluble, and it is only when acted upon by alkalis in the soil that it forms compounds which can be absorbed by plants. Silica, in a soluble state, exists in minute quantities in soils, the proportion, according to Johnston, varying from 0:16 to 0°84 in 100 parts, while the insoluble siliceous matter varies from 60°47 to 83°31 in 100 parts. Wiegman and Polstorf found that plants took up silica from a soil composed entirely of quartz sand, from which everything organic and soluble had been removed. The following table shows the plants which germinated, the height to which they grew previously to being analysed, the quantity of silica they contained when planted, and the increase :— Silica in the ash. Silica had Height. Seed. Plant. increased Barley . - U5imches ... 0°084 ... 0°355 ... 10 times. Oats . oS ys « 0°064 ... 0°54 ... 54 ,, Buckwheat . 18 ,, = 0°004 ... 0075 ... 18 ,, Vetch . 2 AO 4, -. 0013 ... 01385 ... 10 = ,, Clover . . 3s .. 0:009 ... 0091 ... 10 4, Tobacco ADS aa: «. 07001 ... 0°549 ... 500 ,, Atumina exists abundantly in clayey soils, but it does not enter largely into the composition of plants, It has the power of absorbing ammonia and saline matters, and may prove beneficial in this way. Lime is an essential ingredient in all fertile soils. In 1000 lbs. of such soil there are, according to Johnston, 56 Ibs. of lime; while a soil is barren which contains only 4 lbs. The presence of phosphoric acid in soils, in the form of phosphates of potash, soda, and lime, is essential for the production of certain azotised compounds in plants ; and sulphuric acid, similarly combined, is required for the formation of others. Calcareous soils contain upwards of 50 per cent of lime. The addition of lime to soils is often highly beneficial, by destroying noxious weeds, and preventing disease in crops. Lime is a forcing agent, and is useful in stiff clayey soils where it decomposes the silicate of potash, forming silicate of lime, and liberating the potash which is taken up by the plants, In marly soils lime exists in the proportion of 5-20 per cent. In loamy soils lime is in smaller quantity, A rough way of estimating the general nature of a soil is thus given by Professor Johnston :— 136 APPLICATION OF MANURE. 1. Weigh a given portion of soil, heat it and dry it. The loss is water. 2. Burn what remains. The loss is chiefly vegetable matter. 8. Add hydrochloric acid to the residue, and from this the quantity of lime may be determined. 4, Wash a fresh portion of soil to determine the quantity of insoluble siliceous sand. Such an analysis, however, is by no means sufficient for the pur- poses of the farmer. The chemical composition of a plant being known, conclusions can be drawn as to the soil most suitable for its growth. This is a matter of great importance both to the farmer and to the planter. In order that a plant may thrive, even in a suitable soil, exposure and altitude must also be taken into account. It is only by attention to these particulars that agricultural and foresting operations can be successful. As regards trees, the following practical observations are given as an illustration of what has been stated. The Scotch Fir thrives best in a heathy soil, incumbent on a pervious subsoil, and at a high altitude; Larch in loam, with a dry subsoil, in a high situation, and on sloping banks ; Spruce and Silver firs in soft loam or peaty soil, in a low moist situation, but they will also grow in a dry soil, and at a pretty high altitude; Oak in any soil and situation under 800 feet above the level of the sea, but it thrives best in clayey loam, on a rather retentive subsoil, and on gently sloping ground; Ash and Elm, on a gravelly loam, on gravel or sand, at an altitude under 500 feet above the level of the sea ; Sycamore, at 100 feet higher than the ash or elm, and in a more retentive soil and subsoil ; Beech, on a dry gravelly soil, and in a rather high situation, but it is often luxuriant on strong retentive clay, and in a low damp situation. 1 APPLICATION oF Manure. If the soil does not contain the ingredients required for a crop, they must be added in the form of manure. The principle of manur- ing is to supply what the plant cannot obtain from the soil, and to render certain matters already in the soil available for nutrition. In order that this may be properly practised, there must be an analysis of the soil, of the plant, and of the manure. Hence the importance of agricultural chemistry to the farmer. Various kinds of Manure. Narurat Manures, as farmyard dung, are more valuable than simple manures ; inasmuch as the former furnish all the substances required for the growth of plants, while the latter only supply a particular ingredient. Natural manures may be regarded as confer- VARIOUS KINDS OF MANURE. . 187 ring on the soil the most lasting advantage, as from the slowness of their decomposition their beneficial effects are not so readily exhausted. Plants themselves, in a soluble state, would be the best manure. In ordinary farmyard manure the straw is again made available for the purpose of the plant. The whole crop of wheat and oats, however, cannot be returned to the soil, as part must be retained for food. A substitute, therefore, must be found for the portion thus taken away. This contains both azotised and unazotised matters, the former con- sisting of protein compounds which supply nitrogen for the muscular tissue of man and animals; the latter of starchy, mucilaginous, and saccharine matters, which furnish carbon as a material for respiration and the formation of fat. The object of manuring is chiefly to increase the former, and hence those manures are most valuable which contain soluble nitrogenous compounds. The value of manures is often estimated by the quantity of glutin which is produced by their application. Hermbstaedt sowed equal quantities of the same wheat on equal plots of the same ground, and manured them with equal weights of different manures, and from 100 parts of each sample of grain produced he obtained glutin and starch in the following proportions :— Glutin. Starch. Without manure. ‘ “ - ee OF ba 66°7 Cow dung 7 : - - . . 12°0 ss 62°3 Pigeons’ do... : . ‘ . 12:2 als 63°2 Horse do. . ‘ 3 7 5 . 13°7 ais 61°6 Goats’ do. . : , < ‘ . 82°9 sia 42-4 Sheep do . A “ i “ » wae sie 42°8 Dried night soil 3 : < d - 83'1 a 41°4 Dried ox blood . - = . . 842 ee 41°3 Manures containing ammonia owe their excellent qualities to the nitrogen which enters into their composition ; hence the value of sulphate of ammonia, ammoniacal liquor of gas-works, and urine. The value of guano, or the droppings of sea-fowl, depends chiefly on the ammo- niacal salts, and the phosphates which it contains ; thus supplying the nitrogen and phosphorus requisite for the protein compounds which furnish the elements for flesh and blood. The guano which is im- ported is the excrement of numerous sea-fowl which frequent the rainless shores of South America and Africa. It often contains beautiful specimens of Diatoms, as Campylodiscus, Coscinodiscus, etc. The guano found in caves on the coasts of Malacca and Cochin-China is the produce of frugivorous and insectivorous bats, and of a species of swallow—the last being the best. : The following analyses, by Dr. Colquhoun of Glasgow, which are the result of an examination of a large number of samples, give a general idea of the composition of guano, The term ammoniacal 138 . VARIOUS KINDS OF MANURE. matter includes urate of ammonia and other ammoniacal salts, such as oxalate, phosphate, and chloride, as well as decayed organic matter of animal otigin. The term bone earth includes phosphate of lime (always the principal ingredient), phosphate of magnesia (always in small amount), oxalate of lime; and in African guano a minute quantity of carbonate of lime, and from 4 to 2 per cent of fragments of sea-shells, ‘The jiaed alkaline salts are various salts of sodium, as chloride, phosphate, and sulphate ; a little of a potash salt has been detected. South American Guano. ees Middling. Inferior. Low Qualities, Ammoniacal matter 62 es 42 if 28 eee 12... 15 Bone earth , 20 — 24 aks 30 ne 50 ... 37 Fixed alkaline salts 10 ee 14 ist 21 ey LO! 2. 5, Rock, sand, earth O58... 5 oe 3 a 15... 34 Water. : i ee 15 nok 18 ts 13... 9 100°0 100 100 100 100 African Guano, Best Ichaboe. Inferior. Low Quality. Ammoniacal matter x : 45 id 28 a 20 Bone earth . . ‘i 3 20 oe 21 ne 17 Fixed alkaline salts ‘ ‘ 12 Sup 16 ‘ion 14 Rock, sand, earth 5 i 1 as 3 tg 25 Water i f ‘ ‘ 22 a 32 2s 24 100 100 100 The guano from the islands on the British coasts contains the same ingredients, but the soluble salts are generally washed out by the action of rain. The following is the analysis, by Dr. R. D. Thomson, of guano gathered on Ailsa Craig :— Water 2 z . 3 é : 7 . ‘ 50°30 Organic matter and ammoniacal salts, containing 3°47 per cent of ammonia . , 5 p é is e 12°50 Phosphates of lime and magnesia . i 7 . , 12°10 Oxalate of lime . : 5 : ‘ ‘ 3 : 1:50 Sulphate and phosphate of potash, and chloride of potassium 1:00 Earthy matter and sand 5 “i : e , 15-00 Simpte Manvres supply only one or two of the materials re- quired for the growth and nourishment of plants. The ammoniacal liquor of gas-works, in a very diluted state, has been advantageously applied to the soil, on account of the nitrogen which it contains, Soot has also been used, from furnishing salts of ammonia. Nitrates of potash and soda have been recommended not only on account of the VARIOUS KINDS OF MANURE. 139 alkalies, but also on account of the nitrogen which they contain, in the form of nitric acid. The quantity of glutin is said to be increased by the use of nitrates. Carbonate of potash and soda, and chloride of sodium, are frequently used as manures. The latter is especially use- ful in the case of plants cultivated inland, which were originally natives of the sea-shore, as Cabbage, Asparagus, and Sea-kale. As lume is found in all plants, the salts containing it are of great import- ance. It may be used in the caustic state with the view of decom- posing vegetable matter. It also neutralises any acids previously in the soil, such as occur occasionally in boggy and marshy land, abound- ing in species of Juncus, Carex, and Eriophorum, with some Calluna vulgaris. Lime also combines with certain elements of the soil, and sets potash free, which reacts on the silica, and renders it soluble. Lime is sometimes washed down into the subsoil ; and in such cases trenching improves the land. Phosphate of lime is a valuable manure, both on account of the lime, and of the phosphorus which it contains. Without the presence of phosphates, glutin and the protein compounds of plants cannot be formed. Phosphate of lime exists abundantly in animal tissues, and hence it must be furnished by plants. The use of bone-dust as a manure depends in a great measure on the phos- phate of lime which it contains. Besides phosphate of lime, bone-ash contains from 3 to 12 per cent of phosphate of magnesia, carbonate of lime, and salts of soda. The gelatine of bones also seems to act beneficially, by forming carbonic acid and ammonia. Bones are best applied after being acted on by sulphuric acid, so as to form soluble phosphates by decomposition. They are broken into pieces, and mixed with half their weight of boiling water, and then with half their weight of sulphuric acid. The superphosphate thus formed is applied to the soil, either in a dry state by the drill, with sawdust .and charcoal added, or in a liquid state, diluted with 100 to 200 parts of water. Phosphates and other inorganic matters sometimes exist potentially in the soil, but in a dormant state, requiring the addition of something to render them soluble. Allowing the ground to lie fallow, stirring and pulverising it, are methods by which air and moisture are admitted, time being allowed for the decomposition of the materials, which are thus rendered available for plants. Sulphur exists in considerable quantity in some plants, as Crucifere, and it forms an element in albumin ; hence the use of sulphuric acid and of sulphates as manures. Sulphate of lime or gypsum is well fitted as a manure for clover, by supplying sulphur and lime, and absorbing ammonia. Charcoal in a solid state has been applied with advan- tage as a manure. It acts partly by taking up ammonia in large quantity, and partly by combining slowly with oxygen, so as to form carbonic acid. The effects of carbonic acid on vegetation are said to be remarkably conspicuous in some volcanic countries, in which this 140 VARIOUS KINDS OF MANURE. gas is evolved from the bottom of lakes. When it accumulates in large quantities, however, it destroys plants as well as animals. Manvurine with GREEN Crops is sometimes practised. The mode adopted is to sow certain green crops, the roots of which extend deeply into the soil; and when the plants have advanced considerably in growth, to plough them in, and sow a crop of some kind of grain, In this way the nutritive matter from the deeper part of the soil is brought within reach of the roots of the grain crop. Manuring with seaweeds is also resorted to in cases where they are accessible. They supply abundance of carbonate, phosphate, and sulphate of lime, be- sides chloride of sodium. There are considerable differences in their chemical composition ; thus, while in Laminaria saccharina, alkaline carbonates, potash, and iodine, predominate ; in Fucus vesiculosus and serratus, sulphates and soda are in excess, and iodine is less abundant, In the cultivation of the Coco-nut Palm seaweeds act beneficially. Liquip Manurss have of late years been much employed, and the formation of tanks for their reception has been strongly recom- mended, in which the ammonia is fixed by the addition of sulphuric acid or charcoal. They can be applied after vegetation has advanced, and they are in a state to be at once available to the crop. Some have advocated steeping seeds and grains in certain solutions before sowing them. Professor Johnston suggests a mixture of phosphate of soda, sulphate of magnesia, nitrate of potash, common salt, and sulphate of ammonia (1 1b. of each), in ten gallons of water, to steep 300 lbs. of seeds, which are afterwards to be dried with gypsum or quicklime. The following experiment, conducted by Mr. Wilson, at Knock, near Largs, shows the mode of estimating the effects of manures. The land was a piece of three-year-old pasture, of uniform quality. It was divided into ten lots, and these.were treated with different kinds of manure, The quantity of well-made hay is given in lbs.— Produce Rate per Lot. per Acre, Lot 1. Left untouched . ig . 420 ... 3360 », 2 2% barrels Irish quicklime . : . 602 ... 4816 >, 8. 20° cwt. Lime of gasworks 3 - 651 ... 5208 » 4 44 cwt. Wood charcoal eee « 665 .» 5820 >» 5. 2 bushels Bone-dust 7 . 698 ... 5544 1» 6. 18 Ibs. Nitrate of potash ‘ » 742... 5936 > ¢@ 20 lbs. Nitrate of soda . 2 . 784 .. 6272 », 8 24 bolls Soot. ‘ » 819 ... 6552 5395 23 lbs. Sulphate of ammonia . 874 ... 6776 >, 10. 100 gallons Ammoniacal liquor of gas- i 945 7560 works, 5° Twaddell’s hydrometer ( os The value of each application was the same, all were applied at the same time, and the grass also was cut at the same time. EPIPHYTES’ AND PARASITES. 141 Plants are thus employed to form from the atmosphere and soil those organic products which are requisite for the nourishment of man and animals. Nutrition derivable from the atmosphere being generally diffused, is accessible to all plants, and is perpetually re- newed. Nutrition derivable from the soil being fixed to certain localities, requires that those elements contributing to it be mechani- cally supplied as they become exhausted. While an animal consumes carbon so as to form carbonic acid, gives off ammonia in various excretions, transforms organised into mineral matters, and restores its elements to air and earth ; a plant, on the other hand, fixes carbon in its substance, and gives off oxygen, forms from ammonia solid compounds, transforms mineral into organised matters, and derives its elements from the air and earth. Thus, says Dumas, what the atmosphere and soil yield to plants, plants yield to animals, and animals return to the air and earth, a constant round, in which matter merely changes its place and form. EpipHytic AND Parasitic PLANTS. Some.plants grow without any attachment to the soil, and are able to derive in a great measure, from the atmosphere, all the materials required for their growth. Such plants are called Epiphytes (27, upon, and guroy, a plant), or air-plants, and may be illustrated by the Til- landsias, Bromelias, and Orchids of warm climates. Such plants, when attached to the surface of trees, may perhaps derive some nourishment from the inorganic matter in the decaying bark ; but they do not become incorporated with, nor do they send prolongations into, the trees. Orchidaceous plants, which are always perennial, are found in the greatest variety and profusion in those regions where heat and moisture abound. Extremes of cold or dryness are the least favour- able to their growth. Tillandsias and Bromelias flourish in dry hot air without any contact with the earth. There are other plants, however, which are true Parasites (raed, beside, and o/ros, food, deriving food from another), sending prolonga- tions of their tissue into other plants, and preying upon them. Many _ Fungi, for instance, develop their spores (seeds) and spawn (mycelium) in the interior of living or dead plants, and thus cause rapid decay. The diseases of corn, called smut and rust, and the dry rot in wood, are due to the attacks of these parasitic Fungi. The minute dust or powder produced by these plants consists of millions of germs which are easily carried about in the atmosphere, ready to fix themselves on any spot where they can find a nidus. There are also flowering plants which grow parasitically, and they may be divided into two classes : ‘1. Those which are of a pale or brownish colour, and have scales in place of leaves ; and 2. Those which are of a green colour, and have 142 CIRCULATION OF THE SAP. ‘leaves. The former, including Orobanche or broom-rape, Lathrza or toothwort, Cuscuta or dodder, derive nourishment entirely from the plant to which they are united ; while the latter, as Loranthus, Viscum or mistleto, Myzodendron, Thesium, Euphrasia, Melampyrum, and Buchnera, elaborate sap in their leaves under the action of air and light. By this power of elaboration, the mistleto is able to grow on different species of plants, as on the apple, beech, oak, etc. Some parasites are attached by suckers to the roots of plants, as in the case of Broom-rape, Toothwort, and Thesium, and are called root-parasites ; while others, as Dodder, Mistleto, etc. derive nourishment from stems, and are called stem-parasites. The specific names of many parasites are taken from the plants on which they grow. The species of Cuscuta or dodder inhabit all the temperate and warm parts of the globe, and are peculiarly destructive to clover and flax. They are produced from seed which at first germinates in the soil like other plants ; but after the stem has coiled closely round another plant, and become attached to it by means of suckers, then all connection with the soil is severed, and the Dodder lives as a true parasite. A re- markable genus of parasites, called Rafflesia, has been found in Sumatra and Java. The species are leafless, and produce brown-coloured flowers, which are sometimes three feet in diameter. On account of their only producing a flower and root they are denominated Rhizanths (giZa, a root, and dvéos, a flower). 2,—Absorption and Circulation of Fluids. While the leaves and other aerial organs of plants have the power of absorbing fluids, it is chiefly by the roots that this process takes place. The cells of the spongioles or fibrils of the roots are covered by a very delicate membrane (p. 38), which allows the imbibition of fluids to proceed rapidly ; and as additions are made to their extremi- ties, they are constantly placed in circumstances favourable for the reception of fresh nutriment for the plant. Animals having the power of locomotion are enabled, as they exhaust the nutritive matter of one locality, to remove to another. Plants having no provision for locomotion would perish, after taking up all the nourishment in the soil in their immediate neighbourhood, were it not that the roots spread over large areas in search of food. The nutritive materials in the soil, partly derived from the decomposition of its organic and inorganic materials, and partly from the atmosphere, are supplied to the roots in a state of solution ; and as the substances in the cells of plants are usually colloid and denser than the external liquid crystalloid matters, a process of endosmose takes place by which the latter pass in large quantities into the cell through its membranous covering, while a small portion of the former is excreted by exosmose. These move- CIRCULATION OF THE SAP. 143 ments in the contents of cells and vessels take place when fluids of different densities are separated by an animal or vegetable mem- brane. ; If, on opposite sides of an animal or vegetable membrane, we place two fluids of unequal density, having an affinity for the interposed membrane and for each other, the fluid on the one side being thick and gelatinous, whilst the other is thin and watery, two unequal and opposite currents are at once established—the thin fluid setting with a strong and full current through the membrane towards the thicker fluid, which it penetrates ; the thicker fluid, with a more feeble current and in less quantity, reaching the thin fluid with which it mingles. This constitutes Osmose. The inequality in strength and amount of the two currents depends, not so much on the density of the liquids, as on their character, those of a gluey or albuminous nature passing slowly, whilst those of a more liquid’ nature transude very rapidly. If the membrane form a sac or bladder, in which the thick gelatinous fluid is contained, then the thin fluid rapidly passing inwards into the sac penetrates the thick fluid, and thus the amount of fluid in the bladder is increased and its walls are distended. To this inward current the term Endosmose is applied, and conversely, Exos- mose refers to the slow and feeble outward current of the thick contained fluid. In this instance the Endos- mose current is the stronger, but a reversal of the relation of the fluids to the membrane renders the Exosmose current the stronger, consequently the con- tents of the sac are diminished in amount and its walls collapse. The relative rapidity of the Exosmose and Endosmose currents depends on the position of the liquids as regards the membrane ; the strongest cur- rent always setting in towards the most colloid body. In fig. 240 is represented the mode of showing en- dosmose by meahs of a bladder full of syrup, which is attached to the end of a tube, and immersed in water. In this case the water passes rapidly into the bladder by endosmose, so that the fluid rises in the tube, while a portion of the thicker fluid passes out by exosmose. The force of this endosmose may be measured by a graduated tube, as in the figure, or by a tube with a double curvature, as fig. 242, the lower part of which is filled with mercury. In the Jatter case the mercury is pushed upwards into a graduated tube, and thus an endosmometer (“érgov, a measure), or measure of the force of endosmose, is formed. Fig. 240. Fig. 240. Instrument to show Endosmose and Exosmose, consisting of a bladder con- taining syrup attached to a tube, and plunged in a vessel of water. The inward motion of the water (endosmose) exceeds the outward movement of the syrup (exosmose). 144 CIRCULATION OF THE SAP. Dutrochet found that with a membrane of 40 millimetres in diameter, a tube of 2 millimetres, and a solution of sugar, the density of which was 1-083, the fluid rose 39 millimetres in the space of an hour and a half; with syrup, of density 1-145, the rise was 68 milli- metres ; and with syrup, of density 1-228, the rise was 106 millimetres, Syrup, of density 1:3, produced a current capable of raising a column of mercury of 127 inches, which is equal to a pressure of 44 atmo- spheres. Thus the velocity and force of the rise depend in this instance on the excess of density of the enclosed liquid over that of the water outside. Different’ substances act with varying intensity in producing endosmose. The following ratio expresses the variable intensity of endosmose in different cases in which the density of the solution was the same :—Solution of gelatin, 3; of gum, 5:17; of sugar, 11; of albumin, 12. In order that endosmose and exosmose may take place, the liquids must have an affinity for the interposed membrane, and an affinity for each other, and be miscible. The interposed membrane, whether animal or vegetable, is very actively concerned in the intensity and direction of the endosmotiec current. Graham assigns a chemical character to osmose, accompanied with a constant decomposition of membrane. In the living plant the renewal of the membrane forming the septum is constantly taking place, and thus the osmotic action is kept up. The fiuid matters, absorbed by the roots, are carried upwards through the cells and vessels of the stem, as ascending sap; they pass into the leaves, where they are exposed to the influence of air and light, and afterwards return through the inner bark as descending or elaborated sap, and a portion ultimately reaches the root, where it is either excreted or mixed with the new fluid entering from the soil, The presence of light is essential for the elaboration of the sap. Vegetable growth cannot progress unless the vegetable circulation be perfectly accomplished. This act of vegetable vitality may, however, be effected while the plant is removed from the action of light, but the oxygenation of the juices cannot be perfected without their free exposure to its influence, Numerous experiments have been performed in order to show the course of the fluids in oxogenous stems, such as making incisions or notches in the bark and wood of trees at different heights, and noting the points where the sap first made its appearance at different periods of the year, more especially in spring ; also in plunging plants, with their roots, entire into certain coloured solutions, and marking the course of the coloured fluids, These experiments led to the con- clusion that the sap ascends chiefly through the alburnum or newer wood, proceeds to the leaves, and returns by the bark to the root. If incisions are made into the trunk of a tree at different heights early in spring, it is found that the flow of sap (called bleeding) CIRCULATION OF THE SAP. 145 takes place, first from the lower parts of the incisions, and chiefly from the alburnum ; while at a later period of the year it occurs on both sides of the incision, chiefly from the new wood on the lower side, and from the bark on the upper side. If a plant be plunged into a weak solution of acetate of lead (which is capable of being absorbed), the metal may be detected by means of a salt of iodine, first in the new wood, next in the leaves, and then in the bark. A similar experiment may be made by means of weak solutions of potassic ferrocyanide, and of a persalt of iron. From the minuteness of the tissue, and the difficulty of examining the circulation in a living plant, it is not easy to determine the vessels through which the sap moves. In its upward course it appears to pass through the intercellular spaces, the recent woody tissue and the porous vessels, and in its downward course through the laticiferous vessels and cellular tissue of the bark, being also transmitted laterally through the cells of the medullary rays. In some cases, when the bark has been removed, the descent of the sap takes place by the cells of the medullary rays. The sap nourishes the different organs, its carbonic acid’ and water are partly decomposed, combinations’ take place with nitrogen, protoplasm or formative matter is produced, and various secretions are formed in the cells and intercellular passages. Gaseous matters are taken up by the roots of plants, and circulated along with the sap as well as in the spiral vessels. These usually consist of air, carbonic acid, and oxygen. Hales showed the existence of air in the vessels of the Vine, and Geiger and Proust proved that the sap of this plant contained carbonic acid. Some plants, as Ponte- deria and Trapa, float in water by means of air contained in the vessels or in the intercellular spaces. In Vallisneria, the large cells in the centre of the leaves are surrounded by air-cavities, which are seen as dark lines under the microscope. Changes take place in the composition and density of the sap in its upward course. The chief alterations in it take place in the leaves, where it is exposed to the influence of light and air. By this means carbon is fixed, oxygen is given off, and an exhalation of watery fluids takes place. The fluids pass from cell to cell through the leaves, where they are acted upon by air through the stomata, and reach "the vascular and cellular tissue of the bark, where further changes take place. Walker, from his experiments, concluded that no descent takes place until after the development of the leaves. 1 The sap, after being elaborated in the leaves, is sometimes clear _and transparent, at other times it is milky or variously coloured and opaque. The elaborated sap has been called latex, and the vessels transmitting it have been denominated laticiferous (p. 21). The latex contains granules, which exhibit certain movements under the microscope. The movements are analogous to those observed in the L 146 CYCLOSIS. capillary circulation of animals. On account of these movements in the latex, the laticiferous vessels have been denominated Cinenchymatous (aivéw, I move), and the movements themselves are included under the name Cyclosis (xbxAos, a circle). The plants in which the movements are best observed are those having the latex milky or coloured, such as various species of Ficus, Euphorbia, and Chelidonium. In fig. 241 there is represented a small fragment of a leaf of Chelidonium majus (celandine), which shows the current of orange granules in the lati- ciferous vessels, their direction being indicated by arrows. If the young unexpanded sepal of the Celandine is removed from the plant, and put under the microscope, or if the inner lining of the young stipule of Ficus elastica be treated in a similar manner, very obvious motion is seen in the granular contents of the vessels, and this motion is modified by pricking the vessels or by pres- sure, If the microscope be applied to the stipule of Ficus elastica, while still attached to the plant and uninjured, pres- sure with any blunt object on the stipule will be observed to cause a marked oscillation in the vessels, thus showing their continuity. There will also be seen a regular movement from the apex towards the base, independent of external influences, when the stipule is allowed to lie on the field of the microscope without any pressure or injury whatever. This movement has been observed to continue for at least twenty minutes. It is of importance to distinguish between those molecular movements which are caused by injury and pressure, and those which depend on changes going on in the interior of the living plant, The elaborated sap descends through the vessels of the liber. It appears, then, that in the case of Exogenous plants, the fluid matter in the soil, containing different substances in solution, is absorbed by the extremities of the roots, ascends to the stein, passes Fig, 241. Fig. 241. Small portion of the leaf of Chelidonium majus or Celandine (highly magnified), showing a network of laticiferous vessels. The direction of the currents in the vessels is indicated by the arrows. CIRCULATION OF THE SAP. 147 through the woody tissue, porous vessels, and cells, dissolving starch and other matters, and appropriating various new substances. Pro- ceeding upwards and outwards, this sap reaches the leaves, where it is exposed to the air, and is elaborated by the function of respiration, It then returns, or descends chiefly through the bark, either directly or in a circuitous manner, communicating with the central parts by the medullary rays, depositing various secretions, more especially in the bark, and giving origin to substances which are destined to nourish and form new tissues. Finally, it reaches the extremity of the root, where absorption commenced ; a small portion is there excreted, while the remainder mixes with the newly-absorbed fluids, and again circulates in the sap. The rapidity with which the sap ascends is dependent on the endosmotic property of the cells in the roots, and on the density of the fluids, An absorption of water, con- taining various matters in solution, is constantly going on through the extremities of the rootlets. The sap thus formed is carried forward through the cells, vessels, and intercellular passages, by a force which acts by propulsion. The stimulus of light, acting on the cellular tissue of the leaves, enables them to elaborate the organic compounds which are necessary for vegetable nutrition. The leaf-action may be reckoned one of attraction or suction, transpiration ‘giving rise to a constant flow of fluids to supply the place of those exhaled. Dr. Pettigrew has given the following views as to the circulation in plants, and has illustrated them in the accompanying diagram (fig. 242). In spring the sap being mainly concerned in the growth of the branches, development of buds, and evolution of leaves—a vigorous and rapid movement takes place in an upward direction, as at a. During summer, when the plant is elaborating secretions, and storing up nourishment, the course of the sap is partly upwards and partly downwards, represented by the arrows at cd; the ascending and descending currents are indicated as continuous in the direction of the leaves and roots, and thus as it were constituting a true circulation. In autumn, owing to the fall of the leaf, excess of moisture, and a general waning activity in the plant, there is a marked descent of the sap, as shown at b. But besides, and consequent on, those main currents, others exist. Thus the ascending spring and descending autumn currents, being in great measure endosmotic, give rise to unequal Fig. 242. Diagram representing the ascending, descending, and transverse currents in the plant. u, Ascending or spring current. 6, Descending or autumn current, ed, Ascending and descending currents of summer ; these being continuous in the direction of the leaves and roots. ac, Transverse currents. The arrows in this diagram represent the endosmotic currents, the darts the exosmotic ones. 148 PROGRESSION OF THE SAP. exosmotic currents in an opposite direction—i.e, downwards and upwards respectively. In summer exosmotic currents flow equally in both directions. These counter-currents are indicated on the dia- gram by darts pointing in a direction opposite to that of the arrows. One other current exists—viz., a lateral current, represented by hori- zontal darts. By this current, sap which has been abstracted from the currents passing along the main channels, is diffused into sur- rounding tissue. Although the upward and downward currents are respectively most vigorous in spring and autumn, still at all periods of the year currents of sap pass both upwards, downwards, and transversely. In the case of Endogenous plants, observations are still wanting by which to determine the exact course of their fluids. The vascular bundles contain woody vessels, which probably are concerned in the ascent of the sap, and vessels equivalent to those of the bark and of the latex, by which it descends. The cellular tissue is also probably concerned in the movements. Cambium is produced in these plants in the neighbourhood of the vascular bundles, and is thus generally diffused through the texture of the stem. In Acrogenous stems it is likely that the sap follows the same course as in Endogens, although, in regard to both, experiments are still wanting ; according to Hoff- mann there is no channel for the descent of fluids in Acrogens, the sap simply ascending and diffusing itself in the substance of the plant in its progress. In cellular plants transmission of the sap takes place from one cell to another ; and as their texture is often delicate, the movements are rapid. Many of these, as seaweeds, when plunged into water, after having been dried by evaporation, imbibe the fluid with very great rapidity. The CaUSE OF THE PROGRESSION OF THE Sar has been investi- gated by numerous physiologists. While the capillarity of the vessels in the higher plants operates to a certain degree, it would appear that the process of endosmose is that by which the continued imbibition and movement of fluids is: chiefly carried on. From the loss of its watery contents, by exhalation, and the metamorphoses going on during the process of nutrition and secretion, the sap becomes gradually more and more dense, and thus throughout the whole plant there is a forcible osmotic transmission of the thinner fluids, and a constant change in the contents of the cells and vessels. These movements will of course take place with greater vigour and rapidity according to the activity of the processes going on in the leaves, which thus tend to keep up the circulation. While the ascending movement of the sap is powerfully promoted by the active operation at the surface of the leaves, its lateral movements are no less influenced by the individual relations of each distinct cell, since the different func- tions of separate cells, when actively exercised, call into action those vital agencies by which a transmission of the cellular contents is effected. PROGRESSION OF THE SAP, 149 Draper attributes the movement of the sap to capillary attraction, which he considers as an electrical phenomenon. This attraction takes place when a fiuid moistens a capillary tube, and there can be no flow unless a portion of this fluid is removed from the upper extremity ; for capillarity will not of itself raise a fluid beyond the end of the tube. Evaporation and transpiration, which take place in the leaves, remove a portion of the vegetable fluids, and thus they promote the capillary action of the vessels. When two fluids of different kinds come into contact in a tube on different sides of a membrane (which membrane, being porous, may be considered as made up of numerous short capillary tubes), that will pass through most rapidly which wets it most completely, or has the greatest affinity for it. Hence, Draper explains the phenomena of endosmose and exosmose by referring them to capillary attraction, aided by transpiration. Liebig adopts a somewhat similar view of the phenomena, He states that the accurate experiments of Hales have shown the effects of evaporation and transpiration on the movements of sap. Transpira- tion takes place chiefly in clear and dry weather ; and, consequently, is regulated by the hygrometric state of the atmosphere. When the weather is cloudy and the atmosphere moist, transpiration is checked, and stagnation of the juices takes place. The greater the transpira- tion, the greater the supply of fluid necessary. Hence, plants kept in the dry atmosphere of rooms fade from want of a due supply to compensate for transpiration ; and hence the importance of pruning plants before transplanting them, so as to diminish the evaporating surface, and of performing the operation in dull and moist weather, so as to allow the absorption of fluids to keep pace with the transpiration. This process of transpiration, therefore, by forming a vacuum, assists capillary attraction and the atmospheric pressure, and thus the fluids rise. As the process of endosmose and exosmose depends on the chemical affinity and physical character of the fluids on each side of a membrane, the porosity of the membrane, and the attraction existing between it and either of the fluids, it follows that the nature of the parietes of the cells and vessels of plants must have a marked effect on their contents and secretions. The observations of physiologists and chemists thus lead to the conclusion that there are four factors concerned in the circulation of the sap in plants—viz. nutrition, acting as a wis a fronte, as is shown by the current setting most strongly in the direction of most rapid growth ; osmose, indicated by the difference in density between the fluids of the plants and those supplied to it from without ; capillary attraction, consequent on the character of the vessels ; and lastly, evaporation, by which the capillary attraction is kept up, osmose favoured, and nutrition facilitated. To these another may be added,—intermittent mechanical strain, produced by swaying in the 150 PROGRESSION OF THE SAP. wind, which, as Mr. Spencer has shown, exercises considerable in- fluence not only propulsive on the main ascending and descending currents, but also extravasating into the lateral flows. It may be said that there is a vis a tergo, without the presence of leaves, as shown by the experiments of Hales (fig. 243), combined with a vis a fronte, depending on the suction power of the leaves. When cut twigs or flowers are put into water, their functions are kept up for some time by endosmose and capillarity. The latter power has great influence in such a case, and hence the cleaner the cut the better, so that no lacerated or ragged edge may interrupt its operation. In these circumstances, also, small solid particles and colouring matters will enter the tubes. Boucherie found that felled trees, the extremities of which were immediately immersed in various solutions, continued to. imbibe them with great force and rapidity for many days, A Poplar, 92 feet high, absorbed in six days nearly sixty-six gallons of a solution of pyrolignite of iron. Heat and light have a powerful influence on the movements of the sap, by promoting transpiration and the action of the cells. After the winter’s repose the first genial sunshine of spring stimulates the sap to activity, and after the leaves are expanded the circulation goes on with vigour. The effect of leaf-buds in promoting the movement of sap, may be exhibited by introducing a single branch of a vine grow- ing in the open air into a hothouse during winter, thus exposing it to the action of heat as well as light. In this case the leaves are de- veloped, and the fluids are set in motion from the roots upwards, so as to supply this single branch, although in the other branches there is no increase in the circulation. In spring, the first effect of light and warmth is to stimulate the leaf-buds. These enlarge, and the osmotic action commences in their cells. The matter stored up during the winter undergoes changes ; certain substances are dissolved, and thus the sap is thickened, so that. the endosmotic process is powerfully increased, and the whole plant exhibits an active and vigorous circulation. The starch deposited in the previous season becomes converted into sugar and dextrin, it is thus readily acted on by the ascending fluids, and in a state of solu- tion admits of being generally diffused. Towards the latter part of the season when the heat and light decrease, the leaves perform their functions more languidly, and there is a near approach to equilibrium in the density of the fluids, and ultimately there is a cessation of the circulation. The height to which the sap rises in the case of lofty trees with spreading roots is very great. The force with which it ascends has been measured by Hales, and is found to vary according to the state of the weather and the vigour of the plant. By fastening a bent tube, containing mercury, on the stem of a vine, he found in one of his MOVEMENTS IN CELLS—ROTATION. 151 experiments that the sap raised the mercury upwards of thirty inches, The apparatus used by Hales is similar to that used by Dutrochet, to measure endosmose, as is represented at fig. 243, where c is the stem of a L vine cut, tis a bent glass tube fitted {i to the cut extremity of the vine by { a copper ring, v, carefully luted and i secured by a bit of bladder, m; nn, 2h represents the level of the mercury i in the two branches of the lower curvature, before the experiment, and n’ nw’ the level at the conclusion of it. He calculated that the force of the sap in the vine, in some of his experi- ments, was five times greater than that of the blood in the crural artery of the horse. Spectra, MoveMENtTs oF FLUIDs. —Besides this general circulation of the sap, special movements have been observed in the individual cells of plants, which have been included under the name of Rotation (rota, a wheel) or Gyration (gyrus, a circuit or circle). These motions have been de- tected in the cells of many aquatic plants, especially species of Chara and Vallisneria, and in the hairs of Trades- cantia. The currents proceed in a more or less spiral direction, and are rendered visible by the granules of chlorophyll which they carry along with them, There exist also other granules in the fluids, which are coloured yellow by iodine, and are probably of a nitrogenous nature. The species of Chara (fig. 244) in which rotation has been observed, are aquatic plants growing in stagnant ponds, and composed of a series of cylin- drical cells, placed end to end. Some- Fig. 243. Apparatus of Hales, to show the force of ascent of the sap. c, Stem of a vine cut. ¢, Aglass tube with a double curvature attached to the upper part of the vine-stem, by means of a copper cap, v, which is secured by means of a lute and piece of bladder, m mn, Level of the column of mercury in the two portions of the tube at the commencement of the experiment. 2 n/, Level of the mercury at the conclusion of the experiment. 152 MOVEMENTS IN CELLS—ROTATION. times the plant consists of a single central cell ; at other times there are several smaller ones surrounding it, which must be removed in order that the movements which occur in the central cell may be seen. Many of the species are incrusted with calcareous matter, and thus become opaque, while others, as Chara or Nitella flexilis, have no incrustation, and are transparent. Those plants with unincrusted tubular, cells best exhibit movements. In these plants the movements take place between the two membranes of which the cell-wall is composed. They are not interrupted when a division of the cell has been made by <_—& Geo? aw pe se ol »-——> Caress if 1 3 Fig. 245, means of a ligature ; an evident movement may still be observed in either section. Some granules, of a green colour, are attached to the cell-wall, while others are carried with the current which passes along one side and returns by the other, following an elongated spiral direc- tion. In the cells of the branches the descending current is next to the axis. In figure 244 the course of the currents in different cells is indicated by arrows. In Vallisneria spiralis (which includes V. Micheliana and Jac- Fig. 244. A small portion of a Chara, magnified to show the intracellular circulation. The arrows mark the direction of the fluid and granules in the different cells, The clear spaces are parts where there is no movement. The circulation in each cell is independent of that in the others, Fig. 245. Large internal cell of Vallisneria, showing the direction of the currents in intracellular rotation. There is an occasional nucleus seen in the course of the circulation along with the chlorophyll grains, MOVEMENTS IN CELLS—ROTATION. 153 quiniana), the cells in all parts of the plant, leaf, root, flower-stalk, and calyx, contain numerous green granules, and an occasional cyto- blast or nucleus, which, under certain circumstances, are carried, with the juices of the plant, in continual revolution round the walls of each cell (fig. 245). Although in different cells the currents proceed often in different directions, still in any given cell the rotation is uniform ; for if stopped by cold ‘it resumes the same direction. Rotation will continue in detached portions of the plant for several days, or even for three or four weeks. The best way of showing these motions is to take a small portion of a young leaf and divide it in halves, by making a very oblique section on the plane of the leaf, by which means a transparent end is obtained. This should be done at least an hour before it is put under the micro- scope. The part is to be viewed in water, between two pieces of glass ; and a little heat is some- times useful in promoting the movements. In Vallisneria the motion ceases at about 45° Fahr., while in Chara it goes on at a lower temperature ; if the temperature be raised above 150° the motion ceases. A similar intracellular cir- culation is seen in species of Potamogeton, Hydrocharis, and Anacharis, as well as in the moniliform purple hairs on the filaments, and in the calycine hairs, of Tradescantia virginica. In the examination of these hairs a higher microscopic power is required than in the case of the plants previously mentioned. A nucleus is usually seen in the cells of these hairs, and it may either remain immovable, or may be carried along with the current. The movements ap- f ‘ i pear to be confined between a Fig. 246 double cell-wall. Fig. 246 shows : a calycine hair, p, of Tradescantia virginica, with a small portion of Fig. 246. Hair, p, taken from the calyx of Tradescantia virginica, with a small portion of the epidermis, e e, on which there is a stoma, s. In each of the epidermal cells there is a nucleus, m, and currents (rotation), the direction of which is indicated by the arrows. 154 MOVEMENTS IN CELLS—ROTATION. the epidermis, ¢ e, on which a stoma, s, is seen. In each of the cells, both of the epidermis and the hair, there is a nucleus, n, and rotatory currents, the direction of which is indicated by the arrows. In each cell, as seen at a, there are several currents, which cross each other at the point where the nucleus is situated, thus giving rise to the appearance of an irregular network. The hairs of many other flowering plants exhibit rotation (fig. 90), and it is probable that in all young cells these currents may be observed. The circulating fluid is a mucilaginous protoplasm or formative matter, and in Chara and Vallisneria it forms a uniformly investing layer on the inner surface of the cell. The motions would appear to be connected in some way with the nutrition of cells and the formation of new ones; and while they continue throughout life in aquatics, they often cease in plants living in air, after they have attained a certain development. Mohl’s experiments have shown that at the temperature of 66° Fahrenheit the quickest motion was 1-125th of a Parisian line,* the slowest, 1-600th, and the mean, 1-185th. Schleiden says that in the Vallisneria cells it is not the cell-sap that is in motion, but a mucilaginous fluid, with which the chloro- phyll granules and the nucleus are connected, and which flows in an uninterrupted manner along the cell-walls, In Chara, also, he states it is not the cell-sap which moves, but a denser fluid, present in large quantity, and occupying the outer part of the cell cavity. Mohl thinks that a homogeneous protoplasm fills these cells at first com- pletely, but that during growth it becomes hollowed out into one or more cavities, and that around these the mucilaginous matter circulates. The velocity of the currents in various plants, at 66° to 68°" Fahrenheit, is thus given by Mohl :— Filamental hairs of Tradescantia virginica,—3}y to $y of a Parisian line in a second ; mean, ¢$z- Leaves of Vallisneria spiralis—quickest, 4; ; slowest, giy ; mean, z$;; of a line in a second. Stinging hairs of Urtica baccifera—quickest, g}7 ; slowest, s+, ; mean, 7}. Cellular tissue of young shoot os Sagittaria sogtinitonia, rho to rosy 3 Mean, shz i leaf of do., yyy to Te00 ; mean, Tast Hairs of Cucurbita Pepo—quickest, 77> ; slowest, s7gq ; mean, zes7- The measurements were made by noting the passage of the globules across the field of a micrometer, fixed in the ocular of the microscope, and counting the strokes of a seconds pendulum. These movements appear more rapid to the observer ; but then it must be recollected that the parts are seen in a highly magnified state. The cause of those intracellular movements is obscure ; both vital * Parisian line = ‘088815 of an inch. RESPIRATION OF PLANTS. 155 and physical causes having been adduced in explanation. By some they are considered as connected with the nourishment of the cell, the presence of the nucleus, and the process of cytogenesis, Certain authors have referred the phenomena to endosmdse, dependent on varying density in the cell-contents, while electrical agency has been called into requisition by others. In Chara the chlorophyll granules lining the walls of the cells have been supposed to exercise a galvanic action upon the sap, and thus give rise to the motion. Dr. Pettigrew, from experiments by which he succeeded in inducing similar movements artificially, concludes that the ultimate causes are mainly physical, of which absorption, resulting in endosmose and exosmose, and evaporation, are the chief; and that the phenomena are influenced by the general circulation. He says, “‘ while the cells in the root of the plant inaugurate the general circulation, the general circulation in its turn influences the intracellular circulation. This follows, because when a current of fluid travels up the one side of a thin porous cell-wall, and another and opposite current travels down the other or opposite side, a certain proportion of the currents pass obliquely through the cell-wall, and cause the fluid contents of the cell to gyrate or move in a circle. The cell-contents are made to gyrate, even in the absence of opposing currents outside the cell, if endosmotic and exosmotic currents are induced within it; or if evaporation or capillarity be made to act at- certain points.” 3.—Respiration of Plants. The changes which are produced in the atmosphere by living plants have been included under the title of Vegetable Respiration. The experiments of Priestley, in 1771, show that plants when ex- posed to light in an atmosphere containing a considerable proportion of carbonic acid, purify the air by removing carbon and producing oxygen. Air in which animals had died was thus rendered again fit for breathing. Percival confirmed those observations. Scheele made a series of experiments with nitrogen in place of carbonic acid, and he found that plants did not purify an atmosphere composed of nitrogen alone. The foul air then, in his experiments, differed com- pletely from that in Priestley’s experiments, and hence the difference of results, Ingenhouz and Senebier performed numerous experiments, which proved that during the day plants gave out oxygen gas, while during darkness this process was suspended. The former has shown that the green portions of all vegetables, irrespective of their specific properties, are equally available for such operations ; that it is from the under surface of the matured leaves that oxygen is chiefly given off; and that in plants placed in shade the action of the leaves does. not prevent deterioration of the air, Saussure stated that 156 RESPIRATION OF PLANTS. during the night oxygen gas was absorbed in different quantities by plants. Fleshy plants absorbed least ; next came evergreens, and then deciduous trees and shrubs. This absorption of oxygen is attended with the formation of carbonic and other acids. It has been said that some leaves, on account of this process of oxidation, are acid in the morning, and become tasteless during the day. De- candolle, Ellis, Daubeny, and numerous other observers, have con- firmed the conclusions drawn by the early experimenters. The results, of all these observations are, that plants, more especially their leaves and green parts, have the power of decomposing carbonic acid under the influence of solar light, and of evolving oxygen. While in dark- ness no such decomposition takes place, oxygen is absorbed in moderate quantity, and some carbonic acid is given oft. The former process, caused by the deoxidising or rather decarbonising power of plants, much exceeds the latter in amount. And thus the respiratory process in plants and in animals is antagonistic, consisting in the former of the elimination of oxygen, while in the latter it is the elimination of carbon. Burnett endeavoured to show that there are two processes con- stantly going on in plants, one being what he calls digestion, consisting in the fixation of carbon and the evolution of oxygen, and only carried on during the day ; the other being what he calls proper respiration, consisting in the evolution of carbonic acid gas, and carried on at all periods of a plant’s growth. He thinks that his experiments prove the disengagement of carbonic acid from the leaves of plants both during night and day. Carpenter entertains similar opinions, believing that under all circumstances vegetable respiration is a process continued throughout, and essential for vegetable life; that it consists of the elimination from the system of the superfluous carbon, either by its entering into combination with the oxygen of the air, or by giving off carbonic acid to replace the oxygen absorbed. Mr. Pepys is of opinion that the evolution of carbonic acid indicates an abnormal condition of the leaf, which, in the process of healthy active vegetation, absorbs carbonic acid and disengages oxygen. He believes that the action of light leads to the greater perfection of this function, which is less energetically performed if not wholly suspended during the night. The changes produced in the atmosphere are mainly caused by the superficial green parts of plants. The oxygen evolved by plants appears to be derived from the carbonic acid of the atmosphere, the carbon of which is appropriated, and probably partly from the water, the hydrogen of which is assimilated. Light is necessary for these decompositions, and it is probable that the alkalies taken up by the roots aid the process, If the leaves of a plant are bent under an inverted tumbler of water, in a pneumatic trough, and exposed to the sun, bubbles of gas RESPIRATION OF PLANTS. 157 will soon be given off, which are found to be pure oxygen; and any carbonic acid in the water will be diminished in quantity. The same leaves in darkness will not evolve any oxygen, light being essential for the process. The brighter and longer continued the light, the more oxygen is given off, and the greater the quantity of carbon added to the plant. Ifa healthy plant is covered by a bell jar, and exposed to light for twelve hours, oxygen will be formed, and if carbonic acid be added to the air, it will be decomposed, and the oxygen will increase, During the night the action is reversed, and if the plant is left twelve hours in darknéss, the oxygen will decrease, while carbonic acid will increase. Daubeny, from his experiments respecting the action of plants on a known amount of atmospheric air, states that leaves are requisite for the purification of the air, that the action of light on them gives rise to the emission of oxygen and the decomposition of carbonic ‘acid, that for the elimination of oxygen the presence of carbonic acid is requisite, and that the greatest amount of oxygen which can, by vegetable respiration, be added to air confined within a jar is 18 per cent. The following is a simple experiment showing the production of oxygen by green leaves under the action of light. If a green leaf is placed in an atmosphere composed of hydrogen and carbonic acid, and a stick of phosphorus is introduced, no apparent action takes place in the dark, but the moment a beam of light, or the electric light rays, are thrown on it, white fumes of phosphorous anhydride are instantly produced, indicating the combination of the free oxygen, evolved from the leaf under the action of light, with the phosphorus. _ The following are the results of Boussingault’s experiments on the functions of leaves :— . The volume of CO, decomposed, is identical with that of the oxygen produced. . Leaves decompose pure carbonic acid with extreme slowness. . Leaves in presence of ordinary air and CO, effect readily the decomposition of the latter. Leaves decompose CO, in sunlight, when it is diluted with hydrogen, nitrogen, carbonic oxide, or marsh gas. . Leaves lose the power of decomposing carbonic acid as they lose water (becoming a ot F whe . The aoe surface of thick leaves, such as those of the Cherry Laurel, decom- pose more CO, than the under, in the proportion of 4 to 1 in the sun; whereas in the shade it isas 2t0 1. Jueaves having a thin parenchyma do not differ in'the power of decomposing in the upper or under surface. The fixation of carbon probably takes place gradually, giving rise, at different stages, to the formation of various organic compounds, Thus, two molecules of carbonic acid, by losing one atom of oxygen, become oxalic acid ; this oxalic acid, with the aid of water, may yield other acids, from which, by the elimination of oxygen and the addition of the elements of water, various unazotised matters, as starch, gum, and sugar, may be derived; these changes being promoted by the 158 RESPIRATION OF PLANTS. presence of alkalies. The fixation of carbon and hydrogen from the decomposition of carbonic acid and water gives rise to the formation of the various secretions found in the bark and external cells, as chloro- phyll, resin, oil, caoutchouc, and wax. Carbonic acid in solution, as has already been noticed, is taken up in large quantity by the roots of plants from the soil, and it is also absorbed from the atmosphere by the leaves. It may even be formed in the cells of plants during the various chemical changes connected with the elaboration of their juices and secretions. In the interior of plants it is changed in various ways, but it is in the leaves more especially that its decomposition takes place. At night it is given off unchanged, by what Liebig considers as a mere process of exosmose, in consequence of the dissolved acid being no longer assimilated by the action of light. The quantity of this acid given off during the night is by no means equal to that which is absorbed by the plant during the day. The parts of plants which are not green seem to absorb oxygen. Thus, roots and subterranean organs act in this way, and the presence of oxygen seems to be necessary for their growth. There are also certain periods in the life of a plant when carbonic acid is very largely given off, even during the day, depending on a chemical change taking .place in the starch of the plant, by which it is converted into sugar. These periods are germination, flowering, and fruiting. The changes alluded to will be discussed when these subjects are considered, When plants are decaying, or are in an unhealthy state, they undergo chemical changes, by which carbonic acid is formed. : Aquatic plants have the power of decomposing carbonic acid highly developed, and thus the preservation of the purity of lakes and ponds is provided for. In Batavian ponds Pistia Stratiotes is remarkable for its purifying effects, and Sir-H. Davy notices the great vigour of aquatic plants in the lake Solfatara, where carbonic acid was constantly bubbling up on the surface. The oxygenation of the water by aquatics has also been observed by Morren of Geneva. In conclusion, three views of the respiratory process in plants have been advanced— 1. That oxygen is exhaled in large quantity during the day, and a moderate quantity of carbonic acid given off during the night. 2. That carbonic acid is exhaled in greater or less quantity at all times, but during the day it is decomposed, so that oxygen is evolved. 3. That no carbonic acid is evolved by leaves in a healthy state of the plant, but the elimination of oxygen only occurs. The last view is not now accepted by physiologists, Of the others each has a number of adherents—many able physiologists EFFECTS OF GASES ON PLANTS. 159 ranging on either side. The view generally adopted is, that plants give out carbonic acid at certain times, and that the green parts of plants under the influence of light decompose the gas, fix the carbon, and eliminate the oxygen. Experiments have been made as to the effect of the different rays of the spectrum in aiding the decomposition of carbonic acid, by the green parts of plants. The light-giving rays, or those nearest the yellow, appear to have the greatest effect in the fixation of carbon, and in the production of wood ; while the heat-giving, and the tithonic or chemical rays, have scarcely any influence. The tropics and warm climates, where a sky seldom clouded per- mits the'glowing sun rays to shine on a luxuriant vegetation, are the constant and inexhaustible source of oxygen, thus contributing to the respiration of the animals, not only of their own latitudes, but also of the temperate and colder zones, where artificial light and warmth must replace the deficient light and heat of the sun, and which thus produce a copious supply of carbonic acid, to be expended on the nutrition of the tropical plants. The life of animals is thus connected intimately with the vegetable productions of the globe, not merely as regards the materials of their food, but also in reference to the air which they breathe. While the breathing of man and animals, and the various pro- cesses of combustion, are constantly abstracting oxygen from the atmosphere, and substituting carbonic acid, plants are decomposing this noxious gas, and restoring the oxygen. Effects of certain Gases on living Plants. It has been already stated that plants can live in an atmosphere containing a considerable proportion of carbonic acid, provided they are exposed to the light. Thus, an atmosphere which could not be breathed by man and animals is capable of supporting vegetable life. Experiments show, however, that plants will not continue to exercise their functions in pure carbonic acid gas, but that in all cases a certain quantity of free oxygen must be present. It has been found that though plants do not thrive in pure nitrogen, nor in hydrogen gas, yet their vitality is not destroyed by the presence of these gases. Saus- sure observed that a plant of Lythrum Salicaria lived for five weeks in an atmosphere of hydrogen gas, Nitrogen has been proved to be innocuous. These gases seem of themselves to have no directly injurious effects, but to act chiefly by depriving the plants of carbon and oxygen. i There are certain gases, however, which have very prejudicial effects on plants, as proved by the experiments of Turner and Christison. Some of them act as irritant poisons, causing local dis- 160 EFFECTS OF GASES ON PLANTS. organisation ; others as narcotic poisons, inducing a drooping and decay of the entire plant. To the former class belong sulphurous acid gas, hydrochloric acid gas, chlorine and nitrous acid gas; while amongst the latter are included sulphuretted hydrogen, cyanogen, carbonic oxide, and ammonia. SutpHurous Actp Gas is highly injurious to plants. It pro- duces greyish-yellow dry-looking spots on the leaves, which gradually extend until the leaves are destroyed. The effect resembles much the ordinary decay of the leaves in autumn. The proportion of gas, in some experiments, was only 1 in 9000 or 10,000 parts of air, and the quantity + of a cubic inch; and yet the whole unfolded leaves of a mignonette plant were destroyed in forty-eight hours. This proportion of the gas is hardly or not at all discoverable by the smell. Hyprocutoric Acip Gas produces effects similar and scarcely inferior to those of the last-mentioned gas. When ¢ of a cubic inch is diluted with 10,000 parts of air, it acts destructively on Laburnum and Larch, destroying the whole vegetation in less than two days. Even when in quantity not perceptible by the smell, it still acts as an irritant poison. SULPHURETTED HyprocENn acts in a different way from the acid gases. The latter attack the leaves at the tips first, and gradually extend their operation to the leaf-stalks. When in considerable proportion, their effects begin in a few minutes ; and, if diluted, the parts not attacked generally survive if the plants are removed into the air. But in the case of sulphuretted hydrogen, the leaves, without being injured in texture or colour, become flaccid and drooping, and the plant does not recover when removed into the air. It requires a larger quantity of this gas to produce the effects stated. When six cubic inches are added to sixty times their volume of air, the droop- ing begins in ten hours. This gas then acts like a narcotic poison, by destroying life throughout the whole plant at once. These observations point out the great injury which is caused to plants by the gases given off during the combustion of coal, and more especially by certain chemical works. In the vicinity of the latter, the vegetation, for a considerable distance around, is often destroyed, - particularly in the direction of the prevailing winds of the locality. The atmosphere of large manufacturing towns, in which fuliginous matter and sulphurous gases abound, is peculiarly hurtful to vegetable life. In order to protect plants from such prejudicial influences, Mr. N. B. Ward has invented close glass cases, in which plants can be grown independently of the noxious atmosphere around. These cases consist of a trough containing soil, and a frame of glass, which is accurately fitted upon it. The soil is well supplied with water at first, and after the plants are put in, they are kept exposed to the GROWTH OF PLANTS IN WARD’S CASES. 161 light. In these circumstances they will continue ‘to thrive for a long time, even for years, without any fresh supply of moisture or any direct exposure to the air. These Cases are well fitted for rooms where the dryness of the atmosphere interferes with the vigour of plants, by causing greater exhalation than can be compensated by the absorption of moisture by the roots. Some plants, as Ferns, requiring a humid atmosphere, thrive well in such Cases. But it is not merely as objects of luxury and curiosity that these Cases deserve notice. They supply an important means of transport- ing plants, in a living state, to and from foreign climates; and they are in constant use for that purpose. Plants have thus been brought to this country which could not have retained their vitality in the form of seed, and which would have been destroyed by exposure to the sea-breeze and to the vicissitudes of climate experienced during ‘their transport. Plants of Musa Cavendishii have been thus intro- duced into the South Sea Islands, and Tea, Ipecacuan, and Cinchona into our Indian possessions. The stillness of the atmosphere in the Case contributes materially to prevent injurious consequences, In June 1833, Mr. Ward filled two Cases with Ferns,’ Grasses, etc., and sent them from Britain to Sydney, where they arrived in January 1834. The plants were taken out in good condition, and the Cases were re- filled at Sydney, in February 1834, the thermometer then being between 90° and 100° Fahrenheit. In their passage to England they encountered very varying temperatures, The thermometer fell to 20° on rounding Cape Horn, and the decks were covered a foot with snow. In crossing the line the thermometer rose to 120°, and fell to 40° on their‘arrival in the British Channel in the beginning of November, eight months after they had been enclosed. The plants were not once watered during the voyage, and received no protection by day or by night, nevertheless they reached London in a healthy and vigorous condition. It is a mistake to suppose that the air in the Cases remains un- changed. They are not hermetically sealed ; and by the law of diffu- sion of gases there is a constant although gradual mixture of the external air with that inside, free however from many impurities. Plants will continue to grow for a long time, even in Cases hermeti- cally sealed, if supplied at first with abundance of good soil and water. By the united action of the plant and light, the air undergoes constant changes, and thus continues fit for vegetable life. 4.—Products and Secretions of Plants. The sap in its progress through the cells and vessels, and especi- ally in its passage through the leaves, is converted into organisable products, from which the vegetable tissues are nourished and the M 162 VEGETABLE PRODUCTS—STARCH. secretions are elaborated. Light, by enabling plants to fix carbon, has an important influence over these secretions. When plants are kept in darkness they become etiolated or blanched, and do not form their proper sécretions, Gardeners resort to the practice of blanching when they wish to diminish or destroy certain secretions, | and to render plants fit for food ; a familiar example of which may be seen in their culture of Apium graveolens (Celery). In speaking of the contents of cells and vessels, allusion has already been made to some of the more important organisable products. It is proposed in this place to take a general view of those vegetable secretions which are connected with the nutrition of plants, or which are important on account of their medicinal or commercial uses. Some of these occur in small quantity, and are limited to certain plants only ; others are abundant, and more universal in their distribution. Thus, while quinia and morphia, the active ingredients respectively of Peruvian bark, and opium, are circumscribed, both as regards quantity and distribution, starch, gum, sugar, woody matter, and certain nitrogenous compounds, are more abundant, and more generally diffused through- out the vegetable kingdom. The latter substances therefore demand special attention. Ifa plant is macerated in water and all its soluble parts removed, lignin is left, and the water in which it has been macerated gradually deposits starch, If the liquid is boiled a scum coagulates, formed of albumin and some azotised matters, while gum and sugar remain in solution. : Srancu is a general product, being laid up as a store of nourish- ment, and undergoing changes at certain periods of a plant’s life, which fit it for further uses in the economy of vegetation. It is not usually found in animal cells. It consists of C, H,, O,, and occurs in grains of various sizes and shapes, having an external membrane, enclosing a soluble substance. By boiling in water, the pellicle bursts, and the contents are dissolved, becoming gelatinous on cooling. The circular markings and striee seen on the grains, and the part called the hilum, have already been noticed (p. 10). The grains of potato starch, seen by polarised light, exhibit a well-marked black cross, the centre of which corresponds with the hilum. Some plants, such as potato, arrow-root, and wheat, contain a large quantity of starch, which varies, however, in quantity according to the period of growth. Thus, while starch abounds in the potato towards the latter part of the season, it decreases when the tubers begin to germinate in spring. It was found that 240 lbs. of potatoes, left in the ground, contained of starch— In August . . 3 23 to 25 lbs., or 9°6 to 10°4 per cent. », September . 32 ,, 88 4, 4,133 ,, 16 55 »» October “ : 32 ,,40 , 41383 ,, 166 ,, » November . ji 385, 45> 55. 5,16 5 187 3; »Aprl . . . 88, 288, 4 16 4 116, » May. : 3 28 ,,20 , 116, 83 ,, VEGETABLE PRODUCTS—GUM. 163 The quantity of starch remained the same during the dormant state in winter, but decreased whenever the plant began to grow. Starch is stored up in many seeds. It exists in roots, especially in those which are fleshy ; in stems; in the receptacles of flowers ; and in pulpy fruits. The seed-lobes of the Bean and Pea, and many other leguminous plants ; the roots and the underground stem of Maranta arundinacea (arrow-root), and of Canna coccinea (tous- les-mois), Canna Achiras and C. edulis ; the stem of Sago Palms (Sagus Rumphii and farinifera), and of the Cycas order ; the receptacle of the artichoke, and the pulp of the apple, are familiar instances of parts in which starch abounds, The grains of potato-starch are of large size, with pearly or sparkling lustre, having one or more hila, and frequently cracks on the surface. Those of arrow-root are small, and have a dull white appearance, while those of tous-les-mois are larger, and glisten like potato-starch. In some cases starch is associated with poisonous or acrid juices, as in Jatropha Manihot, which yields Cassava and Tapioca, and in Arum maculatum, the underground stem of which furnishes Portland sago. Inulin (Cs H,, O,) is a substance analogous to starch, to which Iodine communicates a brown colour. It is found in the roots and tubers of Inula Helenium (Elecampane), Dahlia variabilis, and Helianthus tuberosus (Jerusalem artichoke); while Lichenin is a variety of starch occurring in Cetraria islandica (Iceland moss). Lichenin or lichen starch consists of O, H,, O,, and is de- posited on the primary cell-wall of the plant, in the form of an encrust- ing layer. By the action of malt, or of sulphuric acid upon starch, by long boiling in water, or by heating up to 400° Fahrenheit, a soluble gummy substance is produced called deatrin* (C, H,, O,), which, when dried, constitutes British gum. It is one of the steps in the process of the conversion of starch into sugar. Gum is one of the substances which are produced abundantly in the vegetable kingdom. Its composition is C,, H,, 0,,, the same as that of Cane-sugar. It exists in many seeds, exudes from the stems and twigs of many trees, and is contained in the juices of others from which it does not exude. It is one of the forms through which organic matter passes during the growth of plants, The different kinds of gums have been divided into those which are soluble in eold water (Arabin, mucilage), and those which only swell up into a gelatinous matter (Bassorin or Tragacanth, Cerasin, and Pectin), Arabin is familiarly known by the name of gnm-arabic or gum-senegal, and is the produce of various species of Acacia, chiefly natives of Arabia, Egypt, Nubia, and Senegambia, such as Acacia Ehrenbergii, tortilis, Seyal, arabica, vera, and albida. From the bark of these plants it exudes in the form of a thick juice, which afterwards concretes into * Dextrin is so called from possessing the property of effecting the right-handed rotation of the plane of polarisation of a ray of polarised light. 164 VEGETABLE PRODUCTS—SUGAR. tears, The characters of gum from the same species of plant are liable to considerable variation ; the same tree may yield a transparent or an opaque, a light or a dark coloured gum. Old stunted trees, in hot and dry seasons, yield most gum. Arabin exists with cerasin in the gum of the Cherry and Plum. Mucilage is present in many of the Mallow tribe, as Malva sylvestris, and Althzea officinalis or marsh mal- low, also in Linseed. In Spherococcus crispus, mucilage is present, of which the formula is C,, H,, 0, Bassorin (C,, H,, O,,) forms the chief part of gum-tragacanth (the produce of several species of Astra- galus), and of gum-bassora. It exists in Salep, procured from the tubercules of Orchis mascula, Cerasin (C,, H,, O,)) is that part of the gum of the Cherry (Cerasus), Plum, and Almond trees, which is insoluble in cold water. Pectin is a substance procured from pulpy fruits, as the apple and pear. It forms a jelly with water, and when dried, resembles gum or isinglass. It is changed by alkalies into pectic acid, which is found in many fruits and esculent roots, Sucar.—This substance, which forms an important article of diet, exists in many species of plants. Sugars have been divided into those which undergo vinous fermentation, as Cane and Grape sugar, and those which are not fermentescible, as Mannite. Cane sugar, C,, H,, O,,, is procured from Saccharum officinarum (sugar-cane), Beta vulgaris (beet-root), Acer saccharinum (sugar-maple), and many other plants. It has been conjectured that the Calamus or sweet cane mentioned in the Old Testament, may be the sugar cane. At all events, the plant was known as early as the commencement of. the. Christian era. In the East and West Indies, at the present time, numerous varieties of cane are cultivated, such as Country cane, Ribbon cane, Bourbon cane, Violet or Batavian cane, which are distinguished by their size, form, the position and colour of their joints, their foliage, and their glumes. Bourbon cane is richest in saccharine matter. Canes demand a fertile soil, and for their perfect maturation they require from twelve to fourteen months. Those which are grown from planted slips are plant-canes, those which sprout up from the old stems are rattoons, After being cut, the canes are crushed (the pressed canes being called begass), the saccharine juice is extracted, evaporated, and crystallised, as Raw or Muscovado sugar, which is afterwards refined in vacuo, so as to form loaf sugar. In 1870 the import of unrefined sugar in Great Britain amounted to 12,798,631 cwts., and of refined sugar 1,710,176 cwts. Maple Sugar is much used in America. It is procured from the sugar maple (Acer saccharinwm) by making perforations in the stem, and allowing the sweet sap to flow out. Two or three holes, at the height of eighteen or twenty inches from the ground, are said to be sufficient for an ordinary tree. The season of collecting is from the beginning of February to the middle of April. Beet Sugar is the VEGETABLE PRODUCTS—LIGNIN. 165 produce of the root of Beta vulgaris, and is extensively manufactured in many parts of the Continent. Manna Sugar, or Manmnite, differs’ from the others in not being fermentescible. Its composition is C5 H,, O,. It is the chief ingredient of Manna, which exudes from the Ornus europea and rotundifolia. From Sicily and Calabria it is imported under the name of flake-manna. Mannite is found in the juices of Mushroom, in Celery, and in Laminaria saccharina, and Eucalyptus mannifera. Dr. Stenhouse has determined the quantity of Mannite in some sea-weeds as follows :— Laminaria saccharina =. 7 . 12 to 15 per cent of Mannite. Halydris siliquosa . ‘ . 5 to 6 per cent o Laminaria digitata ‘ a 4to 5 per cent is Fucus serratus ¢ : 4 rather Jess se Alaria esculenta . ‘ ‘ . about the same 59) Rhodymenia palmata. ‘i 7 2 to 3 per cent 55 Fucus vesiculosus . é 3 1 to 2 per cent 35) Fucus nodosus . é : ‘ nearly the same is Knop and Schnederman have detected Mannite in Agaricus piperatus, and other chemists have found it in Cantharellus esculentus, and Clavellaria coralloides. Grape Sugar, called also Starch sugar or Glucose, is composed of C, H,, O,. It occurs in the juices of many plants, and is a product of the metamorphosis of starch, cane sugar, and lignin. It may be extracted from dry grapes, and may be prepared from starch by the action of an infusion of malt, or of a substance contained in malt, called Diastase. It is less soluble and less sweet than cane sugar. It gives sweetness to gooseberries, currants, apples, pears, plums, apricots, and most other fruits. It is also the sweet substance of the chestnut, of the brewer’s wort, and of all fermented liquors. LicNIn is the substance which gives hardness and. solidity to the cells and vessels of plants. It exists abundantly in the woody tubes, which may be said to be composed of cellulose forming the parietes, and lignin or sclerogen, forming the encrusting matter in the in- terior. The latter dissolves in strong nitric acid, forming oxalic acid, while the former is left undissolved. Lignin cannot be separated in the pure state, and hence its exact composition is unknown, When a portion of the stem of a herbaceous plant, or of newly cut wood, is reduced to small pieces and boiled in successive portions of water, alcohol, ether, diluted acids and alkalies, until everything soluble in these agents is removed, a white fibrous mass remains. This fibrous matter exists in linen and paper; and these substances, when sub- jected to the action of sulphuric acid, are converted into grape sugar. Lignin gives support to the vegetable texture, and is often deposited in concentric layers, It occurs in large quantity in the wood of trees, and is also present in the stem of herbaceous plants, In some ‘ 166 AZOTISED VEGETABLE PRODUCTS. cellular plants it is absent, and the object of many horticultural ‘operations, as blanching, is to prevent its formation. Beet-root and white turnips contain only 3 per cent. Lignin is not coloured by iodine. All these organic substances, consisting of carbon united with'the elements of water, are easily convertible into each other by the action of sulphuric acid and heat. Similar changes are induced during the growth and development of plants, as will be noticed under the head of flowering, fruiting, and germination. In many unazotised matters the proportion of elements is the same, that is, they are isomeric, Thus, cellulose and starch have the same composition (C, H,, O,), and are said to be isomeric. The difference in their qualities seems to depend on the mode in which the atoms which make up the molecule are grouped. The form is altered by a re-arrangement of the component atoms. The unazotised products which have been noticed supply materials for the respiration of man and animals, and probably assist in the formation of fat. It is impossible to notice all the compounds of carbon, oxygen, and hydrogen, found in plants. For example, Salicin, C,, H,, O,, a bitter neutral crystalline substance, is procured from the bark of Salix alba, Helix, purpurea, viminalis, pentandra, etc. ; and Phlorizin, C,, H,, O,,, an analogous substance, occurs in the bark of the roots of the apple, pear, cherry, and plum. AzotTIsED Propucts.—There are certain azotised products which exist in greater or less quantity in plants, and which are particularly abundant in grains and seeds. The nutritive matter of wheat consists of starch or unazotised matter, separable by washing, and of azotised matter or glutin. Glutin is composed of certain protein compounds (fibrin, casein, albumin, emulsin), containing carbon, oxygen, hy- drogen, and nitrogen, with some phosphorus and sulphur. Vegetable Jibrin is the essential part of the glutin of wheat, and of the cereal grains, It may be procured by treating with ether the glutinous mass left after kneading wheat flour in linen bags under water. Vegetable casein or legumin is an essential part of the seeds of Leguminous plants, and also of oily seeds. It may be procured in solution from kidney beans and peas, by bruising them in a mortar with cold water, and straining. Vegetable albumin occurs in a soluble form associated with casein. It forms a small proportion of cereal grains, Wheat is said to contain # to 14 per cent; Rye, 2 to 32 per cent; Barley, z, to 4 per cent; and Oats,z to $ per cent. It is distinguished by coagulating at a temperature of 140° to 160°, and by not being pre- cipitated by acetic acid. Zmulsin, or synaptase, has never been obtained in a state of purity. It is a nitrogenous compound, found in certain oily seeds, as in almonds, It exists in the milky emulsion which these seeds form in water, and it is coagulated by acetic acid, and by heat. In bitter almonds it is associated with a substance a VEGETABLE OILS. 167 called amygdalin (O,, H,, NO,,), on which it acts in a peculiar manner, producing hydrocyanic acid. Diastase is an azotised substance procured from malt, and developed during the germination of plants. It is probably fibrin i in an altered state, and it has the power of promoting the conversion of starch into sugar. The azotised products of plants have a composition similar to blood and muscular fibre, and hence their value in the food of man and animals. The following table gives a general view of the quantity of azotised and unazotised matters occurring in certain plants, with the amount of water and inorganic matter :— Azotised Carbonaceous Water. matter. matter. Ashes. Peas . ei ‘ 16 sa 29 ee 52 3 Beans i ‘ 14 ca 31 Se 52 3 Lentils é ‘ 16 i 33 ata 48 3 Oats . 7 ‘ 18 ish 11 sat 68 3 ; Barley : z 16 a 14 ie 69 2 Potatoes. 7 72 is 2 25 25 1 Turmips . 7 89 sam 1 se 9 1 The following arrangement is given by Fromberg of the compara- tive value of various plants as articles of food, taking into account the protein compounds, and the starch, gum, and saccharine matter which they contain, the highest value being 100 :— Beans . ‘ rn 100 Rye. 5 i ‘ 55 Peas ‘ . 80 Barley. % e 50 Oats “ és 75 Potatoes . ‘ , 45 Wheat . . ‘ 70 Rice . 2 ‘ ‘ 35 Maize. a f 60 As regards the produce of different crops per acre, Johnston. gives the following estimate of the nutritive products which they yield :— Average produce per No. of Ibs. of true acre of tubers and nutriment in pro- grain. duce of an acre. Beet, Mangel-warzel, and. aa: 30 tons . 672 Ibs, Beans 7 80 bushels, or "1980 Ibs. 594 ,, Potatoes. . 7 ‘ 8 tons. . 358 ,, Peas ‘i 2 : . 20 bushels, or 1160 ‘Tos. 348 ,, Barley . i ; 36 bushels, or 1872 Ibs. 248 ,, J erneelGil Artichokes « ‘ 10 tons . . 224 ,, Wheat 3 : : 7 25 bushels, or 1500 Ibs. 180 i Oats . 3 . . . 30 bushels, or 1200 Ibs. 132 ,, Frxep O1ts are found in the cells and intercellular spaces of the fruit, leaves, and other parts of plants. Some of these are drying oils, as Linseed oil, from Linum usitatissimum ; others are fat oils, as that from Olives (fruit of Olea europea); while others are concrete, as Palm oil, The solid oils or fats procured from plants, are Butter of 168 VEGETABLE OILS. Cacao, from Theobroma Cacao ; of Cinnamon, from Cinnamomum zeylanicum ; of Nutmeg, from Myristica moschata ; of Coco-nut, from Cocos nucifera ; of Laurel, from Laurus nobilis; Palm oil, from Elais guineensis ; Shea butter, from Bassia Parkii; Galam butter, from Bassia butyracea; and Vegetable tallow, from Stillingia sebifera in China, from Vateria indica in India, and from Pentadesma butyracea in Sierra Leone. These oils contain a large amount of stearin, and are used as substitutes for fat. Castor Oil, from the seeds of Ricinus communis, differs from other fixed oils in its composition. Decandolle gives the following table to show the quantity of oil got from seeds :— Hazel-nut . 60 per cent by weight. | White Mustard 36 per cent by weight. Garden Cress 57 ,, 45 Tobacco . . 384 4 3 Olive. . . 50 4, is Plum. . . 83 4 a Walnut . . 50 ,, 55 Woad. . . 80 4 i Poppy . . 48 4» ” Hemp .. 2 , ” Almond . . 46 ,, ss Pies ee 3) BA mas ” Euphorbia Lath- Sunflower . 15 ,, 55 yrs. . 41 y 4 Buckwheat . 14 ,, ss Colzaa. . . 38 yy ” Grapes . . 12 4, 5 VEGETABLE Wax is a peculiar fatty matter sometimes found in the stem and fruit of plants. It is procured from several species of Palms, as Ceroxylon Andicola, and Copernicia cerifera, and from the fruit of Myrica cerifera (candle-berry myrtle) and Myrica cordifolia, By boiling these plants in water and compressing them the wax exudes, floats on the water, and may be collected and melted. It is of a greenish yellow colour. By saponification it yields stearic, margaric, and oleic acids, along with glycerin. It therefore more nearly approxi- mates the character of fat than that of wax. Waxy matter also occurs on the exterior of fruits, giving rise to the bloom of grapes, plums, etc., on the outer surface of the bracts of Musa paradisiaca, and on the leaves of many species of Encephalartos. In Cork there exists a fatty substance which, when acted upon by nitric acid, yields suberic acid. Chlorophyll, or the green colouring matter of leaves, is allied to wax in its nature, being soluble in ether and alcohol, but insoluble in water. VoLATILE oR EssENTIAL OILs occur in the stem, leaves, flowers, and fruit of many odoriferous plants, and are procured by distillation along with water. They are called essences, and contain the concen- trated odour of the plant. They usually exist ready-formed, but occasionally they are formed bya kind of fermentation, as oil of bitter almonds, and oil of mustard. Some of them consist of carbon and hydrogen only, as oil of turpentine, procured from various species of Pinus and Abies; oil of juniper, from Juniperus communis ; oil of savin, from Juniperus Sabina ; oil of lemon and orange, from the rind RESINOUS PRODUCTS—CAOUTCHOUC. 169 of the fruit ; and oil of neroli, from orange flowers. A second series contain oxygen in addition, as oil of cinnamon, from Cinnamomum zeylanicum ; otto or attar of roses, from various species of Rose, especially Rosa centifolia ; oil of peppermint, from Mentha viridis ; oil of caraway, from Carum Carui; oil of cloves, from Caryophyllus aromaticus. Oils of this kind are procured from many Labiate, as _ species of Lavandula, Origanum, Rosmarinus, Thymus ; and from the fruit of Umbelliferee, as species of Anethum, Foeniculum, Coriandrum, Cuminum, Petroselinum, Pimpinella; and from some Composite, as species of Anthemis, Pyrethrum, and Artemisia. A third series have also sulphur in their composition, and have a peculiar pungent, often alliaceous smell, with an acrid burning taste, as oil of garlic, and of onion, procured from the bulbs of Allium sativum and Cepa; oil of assafcetida, from Narthex Assafoetida ; and oil of mustard, which is obtained from the seeds of Sinapis nigra when macerated in water by a kind of fermentation induced by the action of a nitrogenous body, myrosin, on a substance called myronic acid, or myronate of potash. A similar oil exists in many Crucifere, as in Alliaria officinalis, Armoracia rusticana, and Cochlearia officinalis, and in several Um- belliferee, yielding gum-resin, as Opoponax, Ferula, Galbanum, etc. Many of the essential oils deposit a solid crystalline matter, called Stearoptene, allied to camphor. This latter substance, which consists .of carbon, oxygen, and hydrogen, is procured from Camphora offici- narum, a native of Japan and India. There is also another kind of camphor, produced in Borneo, from Dryobalanops Camphora. Restnous Propucts.—The milky and coloured juices of plants . contain frequently resins mixed with volatile oils, in the form of balsams, besides a quantity of caoutchouc. The resinous substances found in plants are either fluid or solid. The former may be illus- trated by Balsam of Tolu, procured from Myroxylon toluiferum ; Balsam of Peru, from Myroxylon Pereire ; Balsam of Copaiba from various species of Copaifera, especially Copaifera officinalis and mul- tijuga ; Carpathian Balsam, from Pinus Pinea ; Strasburg turpentine, from Abies pectinata (silver fir) ; Bordeaux turpentine, from Pinus pinaster ; Canada Balsam, from Abies balsamea (Balm of Gilead fir) ; Chian turpentine, from Pistacia Terebinthus, etc. The latter may be illustrated by common resin or Colophony, and Burgundy pitch, from Pinus sylvestris ; Mastich, from Pistacia Lentiscus ; Sandarach, from Callitris quadrivalvis ; Elemi, from several species of Amyris ; Guaiac, from Guaiacum officinale ; Dragon’s-blood, from Dracaena Draco, and Calamus Draco; Dammar, from Dammara australis and orientalis ; Labdanum, from Cistus creticus, and other species ; Tacamahaca, from Calophyllum Cadaba, and from Elaphrium tomentosum ; Resin of Jalap, from Exogonium Purga; Storax, from Styrax officinale; Benzoin, from Styrax Benzoin; Copal, from Vateria indica, etc. Lac, from 170 — ACIDS, ALKALOIDS, AND COLOURING MATTERS. various species of Ficus, as Ficus indica, after attacks of Cocci, and from Aleurites laccifera, and Erythrina monosperma; Euphorbium, from Euphorbia officinarum, antiquorum, and canariensis. Caoutcnovc is in some respects analogous to essential oils. It is found associated with them and with resinous matters, in the milky juice of plants. It is the inspissated juice of various species of Ficus, as Ficus elastica, Radula, elliptica, and prinoides, also of Urceola elastica, Siphonia elastica, and Vahea gummifera, A kind of caout- chouc, called gutta percha, imported from Singapore and Borneo, is procured from Isonandra Gutta, one of the Sapotacee. The milky juice of many orders of plants, as of Euphorbiacez, Asclepiadacez, Apocynaces, Artocarpaceze, and Papayaces, contains caoutchouc or gum elastic. Some of these coloured juices are bland, as that produced by the Cow-tree (Galactodendron utile) ; others are narcotic, as those of Poppy and Chelidonium ; others are purgative, as Gamboge ; others diuretic, as Taraxacum. Orcanic Acips are produced by processes going on in living plants, and exist in vegetable juices often combined with peculiar bases and alkaloids. Thus Citric acid occurs in the fruit of the orange, lemon, lime, red currant, etc. ; Tartaric acid, in the juice of the grape, and in combination with potash in tamarinds ; Malic acid, in the fruit of the apple, gooseberry, and mountain ash ; Tannic acid or Tannin, in oak bark and nut-galls ; Gallic acid, in the seeds of Mango ; Meconic acid, in the juice of Papaver somniferum ; Kinic acid, in the bark of various species of Cinchona. Besides these, there are numerous others, which are characteristic of certain species or genera, To these may be added Hydrocyanic acid, as found in Prunus Laurocerasus, etc., and Oxalic acid, which exists in combination with potash in Rumex acetosa, and Acetosella, Oxyria reniformis, Oxalis Acetosella, and in combination with lime in Rhubarb, and many species of Parmelia and Variolaria. ALKALOIDS OR ORGANIC BASES are azotised compounds found in living plants, and generally containing their active principles. They occur usually in combination with organic acids. Quinia and Cincho- nia exist in the bark of Cinchona, the former predominating in yellow bark, the latter in pale bark; Morphia, Narcotin, Codeia, Thebaia, and Narcein, occur in the juice of Papaver somniferum ; Solania is an alkaloid found in many species of Solanum, as Solanum tuberosum, nigrum, and Dulcamara; Veratria exists in Veratrum Sabadilla and album ; Aconitia in Aconitum Napellus ; Strychnia in Strychnos Nux- -vomica, Sancti Ignatii, Colubrina and Tieuté ; Brucia also in Nux-vomica or false Angustura bark ; Atropia in Atropa Belladonna ; Beberia in Nectandra Rodiei ; Piperin i in Piper longum and nigrum ; Emetina in Cephielis Tpecacuanha ; Caffein (Thein and Guaranin) in Coffea arabica, Thea Bohea and viridis, Paullinia sorbilis and ORGANS OF REPRODUCTION. 171 Ilex paraguensis ; Theobromin in the seeds of Theobroma Cacao or chocolate ; besides numerous others of less importance. These Alka- loids are often found in plants having poisonous properties. CoLoURING MATTERS are furnished by many plants, either directly or by a process of fermentation. Yellow colouring matters are procured from the roots of Curcuma longa (turmeric), from the pulp surround- ing the seeds of Bixa orellana (arnotto), from the Ceylon Gamboge plant (Hebradendron Cambogioides), and various species of Garcinia, as Garcinia Cambogia and’ elliptica, from the flowers of Carthamus tinctorius (saflower), from the stigmata of Crocus sativus (saffron), from a kind of Mulberry (Morus tinctoria), from Reseda Luteola (weld), and from some Lichens, as Parmelia parietina (parietin or chrysophanic acid). Red colouring matters are produced from the root of Anchusa tinctoria (alkanet), from Pterocarpus santalinus, Draceena Draco aeeecien the root of Rubia tinctorum or madder (aliza- rin), the root of Morinda citrifolia (sooranjee), from Heematoxylon campechianum (logwood), Ozesalpinia braziliana (Brazil wood), Cam- wood, Carthamus tinctorius (carthamine), and from some Lichens, as Roccella tinctoria (archil and litmus). Blue colouring matters are furnished by the flowers and fruits of many plants, and from the leaves of some, by chemical action. Indigo, a most valuable dye, is procured by fermentation from various species of Indigofera, as Indigofera tinc- toria, Anil, ceerulea and argentea, as well as from Wrightia tinctoria, Marsdenia tinctoria, Nerium tinctorium, Gymnema tingens, and Isatis tinctoria, etc. The plants in full flower are cut and put into vats with water, fermentation takes place, and a peculiar substance is formed, which, by absorption of oxygen, becomes blue. The best and the largest quantity of indigo is produced on the Delta of the Ganges. Several Lichens yield nitrogenous colouring matters, which give blue and purple colours with alkalies, ete. Lecanora tartarea yields cud- bear (Gyrophoric acid). This acid also exists in Gyrophora pustulata, Section IIJ.—Orcans or REPRODUCTION. Structure, Arrangement, and Functions, The reproductive organs consist of the flower and its appendages, the essential parts being the stamens and pistil. When the flower, or at least the essential organs, ‘are conspicuous, the plants are called Phanerogamous (pavegds, conspicuous, and yé0s, union or marriage), or Flowering plants ; when they are inconspicuous, the plants are Crypto- gamous (xevrrds, concealed, and yémos, union or marriage), or Flower- less plants, The former include Exogens and Endogens, the latter Acrogens and Cellular plants. On careful examination it will be / 172 INFLORESCENCE OR ANTHOTAXIS. found that the organs of reproduction and of nutrition are modifications of each other. The parts of the flower, as regards their development, structure, and arrangement, may all be referred. to the leaf as a type. They commence like leaves in cellular projections, in which fibro- vascular tissue is ultimately formed ; they are arranged in a more or less spiral manner, and are often partially or entirely converted into leaves. 1.—Inflorescence, or the Arrangement of the Flowers on the Amis, The arrangement of the flowers on the axis, or the ramification of the floral axis, is called Inflorescence or Anthotaxts (dvbos, a flower, and ré&sc, order). Flower-buds, like leaf-buds, are produced in the axil of leaves, and these are called floral leaves or bracts. A flower-bud has not in ordinary circumstances any power of extension’ by the develop- ment of its central cellular portion. In this respect it differs from a leaf- bud. In some cases, however, of monstrosity, especially seen in the Rose (fig. 247) and Geum, the central part, A, is prolonged, and bears leaves or flowers. In such cases the flowers are usually abortive, the essential organs being so altered as to unfit them for their functions. Such metamorphoses confirm Goethe’s doctrine, that all the parts of the flower are modified leaves. The general axis of inflorescence is sometimes called rachis (géyic, the spine) ; the stalk supporting a flower, or a cluster of flowers, is a peduncle (pes, a foot (fig. 252 a’); and if small branches are given off by it, they are called pedicels (fig. 252 a"). A flower having a stalk is called pedunculate or pedicellate (fig. 252); one having no stalk is sessile (fig. 258). In deserib- Fig. 247. ing a branching inflorescence, it is common to speak of the Rachis as the primary floral axis, its branches as the secondary floral axes, their divisions as the tertiary floral axes, and so on; thus avoiding Fig. 247. Proliferous or monstrous Rose, showing the prolongation of the axis beyond the flowers. c, Calyx transformed into leaves. , Petals multiplied at the expense-of the stamens, which are reduced in number. /, Coloured leaves representing abortive carpels. u, Axis prolonged, bearing an imperfect flower at its apex, INFLORESCENCE OR ANTHOTAXIS. 173 any confusion that might arise from the use of the terms rachis, peduncle, and pedicel, The PEDUNCLE may be cylindrical, compressed, or grooved ; simple, bearing a single flower, as in Prim- tose; or branched, as in London-pride. It is some- times succulent, as in the Cashew (fig. 248 p), in which it forms the large coloured expansion porting the nut; spiral, as in Cyclamen and Val- sup- Fig. 248. Fig. 249. lisneria (fig. 249); or spiny, as in Alyssum spinosum. In some rushes there is-a green terete and sometimes spiral floral axis (fig. 190). Sometimes the peduncle proceeds from radical leaves; that is, from an axis which is so shortened as to ‘bring the leaves close together in the form of a cluster, as in the Primrose, Auricula, Hyacinth, etc. In such cases it is termed a scape. The floral axis may be shortened, assuming a flattened, convex, or concave form, and bearing numerous flowers, as in the Artichoke, Daisy, and Fig. In these cases it is called a Receptacle or Phoranthium (pogéw, I bear, and évéos, flower), or Clinanthium (xAivn, a bed, and évéos, flower). The Floral axis sometimes assumes a leaf- like or phylloid (pvAdov, a leaf, and ¢fdos, form) appearance, bearing numerous flowers at its margin, as in Xylophylla longifolia (fig. 250), and in Ruscus ; or it appears as if formed by several peduncles united together, constituting a fasciated axis, as in the Cockscomb (fig. 251), in which the flowers form a peculiar crest at the apex of the flattened peduncles. Adhe- sions occasionally take place between the peduncle and the bracts or leaves of the plant, as in the Lime tree, Helwingia, Chailletia, several species of Hibiscus, and in Zostera. The adhesion of the peduncles to the stem Fig. 248. Fruit of Cashew (Anacardiwm occidentale). p, Enlarged peduncle. a, Fruit, or nut. Fig. 249. Pistilliferous plant of Vallisneria spiralis, showing spiral peduncles or flower-stalks, by the uncoiling of which the flowers reach the surface of the water, previous to fertilisation. Fig. 250. Leaf-like (phylloid) flattened peduncle, r, of Xylo- phylla longifolia. f/f, Clusters of flowers developed in a centrifugal or cymose manner, 174 INFLORESCENCE OR ANTHOTAXIS. accounts for the extra-axillary position of flowers, as in many Solanacez. When this union extends for a considerable length along the stem, several leaves may be interposed between the part where the peduncle becomes free, and the leaf whence it originated, and it may be difficult to trace the connection. The peduncle occasionally becomes abortive, and in place of bear- ing a flower, is transformed into a tendril (p. 120); at other times it is hollowed at the apex, so as apparently to form the lower part of the outer floral envelope, as in Eschscholtzia. ( The termination of the peduncle, or * the part on which the whorls of the " flower are arranged, is called the Thala- mus or Torus. The term receptacle’ is also sometimes applied to this, whether expanded and bearing several flowers, or narrowed so as to bear one. It may be considered as the growing point of the axis, which usually is arrested by the production of the flowers, but which sometimes becomes enlarged and ex- panded. Thus, in the Geranium, it is prolonged beyond the flower in the form of a beak; in the Arum it is a club-shaped fleshy column (fig. 260, 2, a); in the Strawberry it becomes a conical succulent mass, on which the seed-vessels are placed; while in Nelumbium it forms a truncated tabular expansion, enveloping the seed-vessels, In some cases it bears naked seeds. In some monstrous flowers, as in Rose and Geum, it is prolonged as a branch bearing leaves (fig. 247). The flowers follow a spiral course round the floral axis, which is subject to laws similar to those which regulate phyllotaxis ; this is easily traced in such plants as Banksia, There are two kinds of injlorescence—one in which flowers are pro- duced in the axil of leaves, beyond which the axis continues to elongate and bears leaves and flowers ; whilst in the other the axis ends in a single terminal flower. In the former the flowers are axillary, the axis extends in an indefinite manner, and the flowers, as they successively expand, spring from floral leaves placed higher on the axis than the leaf from which the first flower was developed. In the latter the single solitary flower terminates and arrests the axis, and the flowers developed subsequently, arise from floral leaves below this central flower, and therefore farther removed from the centre. The first kind of inflorescence is Indeterminate, Indefinite, or Axillary. Fig. 251. Fig. 251. Upper part of flattened or fasciated flowering stem of Celosia cristata (Cocks- comb), having the form of a crest, covered with pointed bracts, and supporting flowers on its summit, INFLORESCENCE. OR ANTHOTAXIS. 175 Here the axis is either elongated, producing flower-buds as it grows, the lower expanding first; or it is shortened and depressed, and the outer flowers expand first. The expansion of the flowers is thus centripetal, that is, from base to apex, or from circumference to centre. This kind of inflorescence is shown in fig. 252, where the leaf from which the cluster of flowers is produced, f, represents the bract or floral leaf. The rachis, or primary axis of the flower, is a’; this produces small leaflets, 6, which bear smaller flower-leaves or bractlets, from which peduncles or secondary axes spring, each bearing single flowers. The whole inflorescence is the product of one branch, the lower flowers having expanded first, and bear- ing fruit, while the upper are in bud, and the middle are in full bloom. In fig. 253, the same kind of inflorescence is shown on a shortened axis, the outer flowers expanding first, and those in the centre last. Fig. 252. The second kind of Inflorescence is Determinate, Definite, or Terminal. In this the axis is either elongated and ends in a solitary flower, which thus terminates the axis, and if other flowers are produced, they belong to secondary axes farther from the centre; or the axis is shortened and flattened, producing a number of separate floral axes, the central one expanding first, while the others are developed in succession farther from the centre. The expansion of the flowers is in this case centri- Jugal, that is, from apex to base, or from centre to circumference. It is illustrated in fig. 254, where a representation is given of a plant of Ranunculus bulbosus ; @ is the primary axis swollen at the base in a bulb-like manner, 6, and with roots proceeding from it. From the Fig. 252. Raceme of Barberry (Berberis vulgaris), produced in the axil of a leaf or bract, J, which has been transformed into a spine, with two stipules, s, at its base. a’, Primary floral axis, bearing small alternate bracts, 6, in the axil of which the secondary axes, a” a”, are produced, each terminated by a flower: The expansion of the flowers is centripetal, or from base to apex; the lower flowers have passed into the state of fruit, the middle are fully expanded, and those at the top are still in bud. Indeterminate simple inflorescence. Fig. 253, Head of flowers (capitulwm) of Scabiosa atro-purpurea, The inflorescence is simple and indeterminate, and the expansion of the flowers centripetal, those atthe circum- ference opening first. 176 INDEFINITE INFLORESCENCE. leaves which are radical proceeds the axis ending in a solitary terminal flower, 7. About the middle of this axis there is a leaf or bract, from which a secondary floral axis, a’, is produced, ending in a single flower, f", less advanced than the flower f. This secondary axis bears a leaf also, from which a tertiary floral axis is produced, a”, bearing an unexpanded solitary flower, f”. From this tertiary axis a fourth is in progress of formation. Here f is the termination of the primary axis, and this flower expands first, while the other flowers are developed centrifugally on separate axes. It is a definite inflo- rescence, with numerous floral axes. Fig, 255. InpeEFinite InFLoREscEeNcE.—The simplest form of this inflores- cence is when single flowers are produced in the axils of the ordinary Fig. 254, Plant of Ranunculus bulbosus, showing determinate inflorescence. a’, Primary floral axis dilated at its base, so as to form a sort of bulb, b, whence the roots and radical leaves proceed. /’, Solitary flower, terminating the primary axis. About the middle of the axis a leaf is developed which gives origin to a secondary axis, a”, ending in a solitary flower, Jf”, which is not so advanced as f’.. On the secondary axis a leaf is formed, from the axil of which a tertiary axis, a”, proceeds, ending in a flower, f”, which is still in bud. On this axis another floral leaf and bud is in the progress of formation. Fig. 255. Branching raceme or so-called panicle of Yucca gloriosa. a’, Primary axis or rachis. a”, Secondary axes or smaller peduncles, «a’”, Tertiary axes or pedicels bearing flowers. } bb b, Bracts and bractlets, in the axil of which the axes are produced. The inflorescence is indeterminate and consists of a series of racemes on a common axis, a’, The expansion of the whole in- florescence is centripetal, and such is also the case with each of the racemes forming it, the flowers at the base of the successive axes opening first. ‘ INDEFINITE INFLORESCENCE, - 177 leaves of the plant, the axis of the plant elongating beyond them, as in Veronica hederifolia, Vinca minor, and Lysimachia nemorum. 'The ordi- nary leaves in this case become floral leaves or bracts, by producing flower-buds in place of leaf-buds. The flowers, being all offshoots of the same axis, are said to be of the same generation or degree, and their number, like that of the leaves of this main axis, is indefinite, varying with the vigour of the plant, Frequently, however, the floral axis, arising from a more or less altered leaf or bract, instead of ending in a solitary flower, is prolonged, and bears numerous leaflets, called bracteoles or bractlets, from which smaller peduncles are produced, and those in their turn may be branched in a similar way. According to the nature of the subdivision, and the origin and length of the flower- stalks, numerous varieties of floral arrangements arise. When the primary peduncle or floral axis, as in fig. 252 a’, is elongated, and gives off pedicels, a’, of nearly equal length ending in single flowers, a raceme or cluster is produced, as in Currant, Hyacinth, and Barberry. If the secondary floral axes give rise to tertiary ones, the raceme is branch- ing, and forms-what is by some called a panicle ; but it is better to restrict this term to the lax inflorescence of some grasses andrushes, In Fig. 257. fig. 255 is represented a branching raceme or so-called panicle of Yucca gloriosa, a’ being the primary axis or rachis with bracts, giving off numerous secondary axes, a’, which in their turn develop tertiary axes, Fig. 256. Corymb of Cerasus Mahaleb, produced in the axil of a leaf which has fallen, and terminating an abortive branch, at the base of which are modified leaves in the form of scales, e. a’, Primary axis, or peduncle, or rachis, producing alternate bracts, 0 b, from the axil of which secondary axes or pedicels, a” a”, arise, each bearing a single flower. The expansion of the flowers is centripetal. Fig. 257. Branching corymb of Pyrus torminalis. a’, Primary axis. a” a”, Secondary axes. a” a”, Tertiary axes or pedicels bearing the flowers. 00, Bracts. N 178 INDEFINITE INFLORESCENCE. a a, The development in each of the secondary axes is centripetal, bbdb being the bracts from which the separate axes are produced. If in a raceme the lower flower-stalks are elongated, and thus all the flowers are nearly on a level, a corymb is formed, which may be simple, as in fig. 256, where the primary axis, a, divides into secondary axes, a’ a’, which end in single flowers ; or branching, as in fig. 257, where the secondary axes again subdivide. Fig. 258. Fig, 259. Fig. 260. If the peduncles or secondary axes are very short or awanting, so that the flowers are sessile, a spike is produced, as in Plantago and. Verbena officinalis (fig. 258). The spike sometimes bears unisexual flowers, usually staminiferous, the whole falling off by an articulation, as in Willow or Hazel (fig. 259), and then it is called an amentum or catkin ; at other times it becomes succulent, bearing numerous flowers Fig. 258. Spike of Verbena officinalis, showing sessile flowers on a common rachis ; the in- florescence indefinite, and the evolution of the flower centripetal. The flowers at the lower part of the spike have passed into fruit, those towards the middle are in full bloom, and those at the top areonlyin bud. Fig. 259. Amentum or catkin of Hazel (Corylus Avellana), consisting of an axis or rachis covered with bracts in the form of scales (squame), each of which covers a male flower, the stamens of which are seen projecting beyond the scale. The catkin falls off in a mass, separating from the branch by an articulation. Fig. 260. Spadix or succulent spike of Arum maculatum, 1 Exhibits the sagittate leaf, the spathe or sheath- ing bract, 0, rolled round the spadix, the apex of which, a, is seen projecting. 2 Shows the spathe, 6, cut longitudinally, so as to display the spadix, a. f, Female flowers at the base. m, Male flowers. On the spadix above the male flowers there are numerous abortive flowers indicated by hair-like projections. INDEFINITE INFLORESCENCE, 179 surrounded by a sheathing bract or spathe, and then it constitutes a spadix, which may be simple, as in Arum maculatum (fig. 260), or branching, as in Palms. A spike bear- ing female flowers only, and covered with scales, is either a strobilus, as in the Hop ; or a cone, as in the Fir (figs, 217, 218). In grasses there are usu- ally numerous sessile flowers arranged in small spikes, called Locuste or sptkelets, which are either set closely along a central axis, or are produced on secondary axes formed by the branching of the central one; to the latter form the term Panicle is applied. Fig. 262. : If the primary axis, in place of being elongated, is contracted, Fig. 261. Several umbels, o’ o' o’ o’, of Aralia racemosa. a, General Axis or the apex of the branch terminated by a single umbel farther advanced than the rest. a’ a a’ a’, Axes arising from it, which are secondary as respects the general axis, a; each of them bears an umbel, and as regards this inflorescence they are primary. a” a” a”, Secondary axes, or the radii of the umbel. 00, Bracts placed alternately on the general axis. d, Shows a double pbudgproceeding from the axil ofZone of these bracts, and thus giving rise to two stalked or stipitate umbels, 47%, Verticillate bracts, forming involucres at the base of the radii of the umbels. Fig. 262. Compound umbel of Carrot (Daucus Carota) a’, Primary axis shortened and depressed, so as to present a convex surface. a” a’, Secondary axes, or radii of the general umbel, each ending in a partial umbel or umbellule, 0” 0” 0” 0”. a’” a”, Tertiary axes or radii of the partial umbels or umbellules. 7¢, Pinnatipartite bracts, form- ing the general involucre. 7” i”, Simple bracts, forming the partial involucre or involucel. Fig. 263. Capitulum, Anthodium, or Head of flowers of Scorzonera hispanica. 0, Imbricated bracts, forming an involucre. /j, Florets or small flowers on the receptacle, having a centri- petal evolution. 180 INDEFINITE INFLORESCENCE. it gives rise to other forms of indefinite inflorescence. When the axis is so shortened that the secondary axes arise from a common point, and spread out as radi of nearly equal length, each ending in a single flower, or dividing again in a similar radiating manner, an Umbel ig produced, as in figs. 261 and 262. In fig, 261 the floral axes, a a’ a’, end in simple umbels, o' o’ o’, and the‘ umbels are called stipitate or stalked ; while in fig. 262 the primary floral axis, a, is very short, and the secondary axes, a’ a’, come off from it in a radiating or umbrella-like manner, and end in small umbels, 0", which are called partial umbels or umbellules, to distinguish them from the general wmbel arising from the primary axis. This inflorescence is seen in Hemlock, and other allied plants, which are hence called Umbelliferous. : If there are numerous flowers on a flattened, convex, or slightly Fig. 265. Fig. 266, concave receptacle, having either very short pedicels or none, a capi- tulum (head) or anthodiwm (dvéog, a flower, 60é¢, a way or method), Fig. 264. Capitulum of Scorzonera hispanica cut vertically. +, Receptacle, Phoran- thium, or the flattened and depressed apex of the peduncle, bearing the florets, f, which are surrounded by bracts, 0. Fig. 265. Inflorescence of Dipsacus sylvestris. Capi- tulum, or head of flowers, each of which is surrounded by long pointed bracts. The flowers are evolved ina centripetal manner. e i, The first expanded, followed by those at em, while those at the apex, es, are in bud, Fig. 266. Inflorescence of Dorstenia Con- trayerva, consisting of a broad slightly concave receptacle, 7, in which numerous male and female flowers, f, are placed. Fig. 267. Inflorescence of Fig (Ficus Carica), showing the hollow receptacle, r, or peduncle (which is popularly called the fruit), covered with flowers, f, of various kinds. INDEFINITE INFLORESCENCE. 181 or calathiwm, (xardééiov, a small cup), is formed, as in Dandelion, Daisy, and other composite plants (figs. 263 and 264); also in Scabiosa (fig. 253), .and Dipsacus (fig. 265). Such a receptacle or shortened peduncle may sometimes be folded so as to enclose partially . a = i ail LOS fy - Fig. 268, ot completely a number of flowers (generally unisexual), giving rise to the peculiar inflorescence of Dorstenia (fig. 266), or to that of the Fig (fig. 267), where f indicates the flowers placed on the inner sur- face of the receptacle, and provided with bracteoles. This inflorescence has been called Hypanthodium (iad, under, &véos, a flower). Lastly, we have what are called compound indefinite inflorescences, Fig. 268. Anemone nemorosa. a, Subterranean stem. f, Leaf. d, Floral axis producing bracts, b, which form a three-leaved involucre, e, Solitary flower terminating the axis. In- florescence definite. 182 DEFINITE INFLORESCENCE. Thus we may have a group of racemes arranged in a racemose manner, on a common axis forming a raceme of racemes or a compound raceme, as in Astilbe. In the same way we may have compound umbels, as in Hemlock and most Umbellifere (fig. 262), a compound spike, as in Rye-grass, a compound spadix, as in some palms, and a compound capitulum, as in the Hen-and-Chickens Daisy. Again, there may be a raceme of capitula, that is, a group of capitula disposed in a race- mose manner, as in Petasites, a raceme of umbels as in Ivy, and so on, all the forms of inflorescence being indefinite in disposition. On reviewing these different kinds of inflorescence, it will be observed that the elongation or shortening of the axis, and the pre- sence or absence of stalks to the flowers, determine the different varieties. Thus, a spike is a raceme in which the flowers are not stalked, the umbel is a raceme in which the primary axis is shortened, the capitulum or head is a spike in which the same shortening has taken place. Derinitz INFLORESCENCE.—The simplest form of this inflores- cence is seen in Anemone nemorosa (fig. 268), or in Gentiana acaulis (Gentianella), where the axis termi- nates in a single flower ; and if other flowers are produced, they arise from the leaves below the first-formed flower. The general name of Cyme is applied to the arrangement of a group of flowers in a definite inflor- escence. It is sometimes difficult to understand the mode of development or evolution of the flowers in such an inflorescence, if the axes are much contracted, and the flowers them- selves are numerous. It may be distinctly traced, however, in plants with opposite leaves, in which the different axes are clearly developed. Fig. 269. In fig. 269 is represented the flower- ing branch of Erythreea Centaurium. Here the primary axis, a’, ends in a flower, f’, which has passed into the state of fruit, At its base two leaves are produced, each of which is capable of developing buds. These are flower-buds, and constitute secondary axes, a” a’, ending in single flowers, f" f”, which are thus terminal and solitary; and at Fig. 269. Flowering branch of Erythrea Centaurium. a’, Primary axis, a” a”, Two secondary axes. a” a” a, Tertiary axes, four in number. a’ a!” a”, Quaternary axes, eightin number. The flowérs are shown in various stages of development. /’, Solitary flower which has passed into fruit, terminating the primary axis. jf”, Flowers less advanced, ter- minating the secondary axes. f”, Flowers in bud at the extremity of the tertiary axes, and s0.0n. Inflorescence definite or determinate, Evolution of flowers centrifugal. DEFINITE INFLORESCENCE. 183 the base of these axes a pair of opposite leaves is produced, giving rise to tertiary axes, a” a” a”, ending in single flowers, f” f” f”, and soon. The divisions in this case always take place by two, or in a dichotomous (dia, in two ways, and réwvey, to cut) manner, Had there been a whorl of three leaves in place of two, the division would have been by three, or trichotomous (ree, in three ways). This inflorescence constitutes the Cyme, by which we mean an inflorescence formed by the successive development of unifloral axes from pre-existing axes, limited in extent only by the vigour of the plant ; the floral axes being thus evolved in a centrifugal manner. The cyme, elongated according to its development, has been cha- racterised as biparous (bis, twice, and pario, I produce), or uniparous (unus, one). In figs. 270 and 271, the biparous cyme is represented Fig. 270. Fig. 271. in two species of Cerastium, belonging to the natural order Caryo- phyllaceze, in which cymose inflorescence is of general occurrence. The leaves in the figures are small bracts giving origin to flower-buds in the same way as in fig. 269 ; the flowers at a’ a’ being the termination of the primary axis, and expanding first, the others being subsequently developed in a centrifugal order. In some of the Pink tribe, as Dianthus barbatus, Carthusianorum, etc., in which the peduncles are Fig. 270. Inflorescence (biparous cyme) of Cerastium grandiflorum. 6 b b, Opposite bracts produced at each of the branchings. The axes are indicated as in last figure. The primary axis, a’, ends in a flower which has passed into fruit. Inflorescence determinate. Evolution of flowers centrifugal. Fig. 271. Inflorescence (biparous cyme) of Cerastium tetrandrum, Letters have the same meaning as in the last two figures, In the quaternary axes, a’, the inflorescence becomes unilateral by the non-development of the flower-buds on one side. , 4 a: 184 DEFINITE INFLORESCENCE. short, and the flowers closely approximated, with a centrifugal expan- sion, the inflorescence has a contracted cymose form, and receives the name of fascicle, A similar inflorescence is seen in such plants as Xylophylla longifolia (fig. 250). When the axes become very much shortened, the arrangement is more complicated in appearance, and the nature of the inflorescence is only indicated by the order of opening of the flowers. In labiate plants, as the dead-nettle (Lamium), the flowers are produced in the axil of each of the leaves, and might be looked upon as ordinary whorls, but on examination it is found that the central flower expands first, and from its axis two secondary axes rise, and the expansion is thus centrifugal. The inflorescence is therefore a contracted biparous cyme, the flowers being sessile, or nearly so, and the clusters are called werticillasters (verticillus, a kind of screw). Sometimes, especially towards the summit of a biparous cyme, owing to the exhaustion of the growing power of the plant, one of the bracts only gives origin to a new axis, the other remaining empty, and thus the inflorescence becomes uni- lateral, and further development is arrested (fig. 271 6). Pig. 279 A branching biparous cyme is an] observed in the privet (fig. 272). In this the primary floral axis a’ gives rise to secondary axes a’ a’, along its whole length. These, in a similar manner, produce tertiary axes, a”, which again dividing in a cymose manner, the whole inflorescence acquires an appearance not unlike a bunch of grapes, and has re- ceived from some the name of thyrsus. In the uniparous cyme a number of floral axes are successively de- veloped one from the other, but the axis of each successive generation, instead of producing a pair of bracts, produces only a single one. Here the basal portion of the successive axes collectively forms an apparent or false axis, and the inflorescence thus simulates a raceme. In the raceme, however, we find only a single true axis, producing in succes- Fig. 272. Branching biparous cyme or thyrsus of Privet (Ligustrum vulgare). The primary axis, a’, gives off secondary axes, a” a”, which are opposite to each other, and produce ter- tiary axes, a’ a, which are dichotomous, and consequently end in small three-flowered cymes, cc. Of the three flowers terminating these tertiary axes, the central one expands first, the evolution of the others being centrifugal. DEFINITE INFLORESCENCE. 185. ‘sion a series of bracts, from which the floral peduncles arise, and thus each flower is on the same side of the true axis as the bract, in the axil of which it is developed; but in the uniparous cyme the flower of each of these axes, the basal part of which unites to form the false axis, is situated on the opposite side of the. axis to the bract from which it apparently arises (fig. 275). But this bract is not the one from which the axis terminating in the : es flower arises, but is a bract produced upon that axis, and gives origin in its axil to a new axis, the basal portion of which, constituting the next part of the false axis (as in fig. 275), intervenes between this bract and its parent axis. The uniparous cyme presents two forms, the scorpioid (scorpio, a scorpion), and the helicoid (¢u&, a spire, and pQ 60s, form). In the scor- 7 pioid the flowers are ar- ranged alternately in a double row along one side of the false axis (fig. 274), the bracts when developed Fig. 273. forming a second double Fig. 274, row on the opposite side, as seen in the Henbane; the whole in- florescence usually curves on itself like a scorpion’s tail, hence its name. In fig. 273 we have a diagrammatic sketch of this arrangement. The false axis abc d is formed by successive genera- tions of unifloral axes, the flowers being arranged along one side alternately and in a double row; had the bracts been developed they would have formed a similar double row on the opposite side of the false axis ; the whole inflorescence is represented as curved on itself. In fig. 274 (Forget-me-not) the same scorpioid form of uniparous cyme is seen, with the double row of flowers on one side of the false axis, but in this case the bracts, which should appear on the opposite side, are not developed, and hence the cyme is not complete. In the helicoid cyme there is also a false axis formed by the basal portion of the separate axes, but the flowers are not placed in a double row, but in a single row, and form a spiral or helix round the false axis. In Alstrémeria, as represented in fig. 275, the axis, a’, ends in a flower (cut off in the figure) and bears a leaf. From ' the axil of this leaf, that i is between it and the primary axis, a’, arises a secondary axis, a”, ending in a flower f’, and producing a leaf about the middle. From the axil of this leaf, a tertiary floral axis, Fig. 273. Diagram to show the formation of a scorpioidal cyme, consisting of separate axes,abede. Fig. 274. Scorpioidal or gyrate cyme of Forget-me-not (Myosotis palustris). 186 MIXED INFLORESCENCE, a", ending in a flower f”, takes origin. In this case the axes are arranged, not in two rows along one side of the false axis, but are placed at regular intervals, so as to form an elongated spiral round it. In the Bell-flower (Campanula), (fig. 276), there is a racemose uni- parous cyme, developed in a very irregular manner, and giving rise to a peculiar mixed inflorescence ; a a’ is the primary axis, ending in a flower, f', which has withered, and giving off secondary axes, a” a’, each terminated by a flower, and developed centripetally, the lowest being most expanded. In Streptocarpus polyanthus, and in several calceolarias, we probably have examples of compound definite inflores- cence. Here there are scorpioid cymes of pairs of flowers, each pair con- sisting of an older and a younger flower. Mrxep INFLORESCENCE.—Forms of inflorescence occur, in which’ both the definite and indefinite types are represented. Thus, in Com- posites, such as Hawkweeds (Hieracia), the heads of flowers, taken as a whole, are developed centrifugally, the terminal head first ; while the Fig. 275. False raceme or helicoid cyme of a species of Alstrémeria. a/ a” a” a’. Separate axes successively developed, which appear to form a simple continuous raceme, of which the axes form the internodes, It isa definite uniparous inflorescence, however, with centrifugal evolution. Each of the axes is produced in the axil of a leaf, and is terminated by a flower, f’ f” f” f’", opposite to that leaf, and the axes have a spiral arrangement. Fig. 276. Uniparous racemose cyme, or cymose raceme of Campanula, a/, Primary axis, termi- nated by a flower, j’, which has already withered, and is beginning to pass into the state of fruit. a’ a” a’, Secondary axes, each terminated by flowers, f”, which are more advanced tthe lower they are in their position, MIXED INFLORESCENCE. 187 florets, or small flowers on the receptacle, open centripetally, those at the ‘circumference first. So also in Labiate, such as dead-nettle (Lamium), the different whorls of inflorescence are developed centripetally, while the florets of the verticillaster are centrifugal. Sometimes this mixed character presents difficulties in such cases as Labiatw, where the leaves, in place of retaining their ordinary form, become bracts, and thus might lead to the supposition of all being a single inflorescence. In such cases, the cymes are described as spiked, racemose, or panicled, according to circumstances. In Saxifraga umbrosa (London pride), and in the horse-chestnut, we meet with a raceme of scorpioid cymes ; in sea-pink, a capitulum of contracted scorpioid cymes (often called a glomerulus) ; in Laurustinus a compound umbel of dichotomous cymes. In concluding this subject of inflorescence, the following diagrams may serve to illustrate the different types of inflorescence :— a, Fig, 277. Fig. 278. Fig. 279. Fig. 277 shows an indefinite inflorescence—i.c. one in which all the flowers belong to the same axis. Here we have a single elongated axis, giving off laterally a floret (1), which expands first ; beyond this the axis elongates and gives off another floret (2), which expands after the first one—and so on were the axis elongated farther, _ Thus, in this case, the flowers develop from below upwards, and if we were Fig. 277 shows indefinite inflorescence, in which the lower floret (1) expands first, and then the upper floret (2). Fig. 278 shows definite inflorescence, where the terminal floret (1) opens first, and then the lower floret (2). Fig. 279 shows definite inflorescence with numerous floral axes, The first floral axis bears a flower (1), which opens first ; from this axis come off two floral axes (2 2), the flowers of which expand next; then each of these gives off two floral axes (3 3, 8 3), which expand third in order, and so on. 188 TABULAR VIEW OF INFLORESCENCE. to shorten the axis, and have all the flowers rising from its contracted termination, we should find that the outer flowers expanded first and were followed by the inner ones, the development being then centri- petal, and as the development of flowers from the main axis is limited only by the vigour of the plant, the inflorescence is called indefinite, Fig. 278 shows a definite inflorescence. In this case all the flowers do not belong to the same axis, but the first axis elongates and terminates in a single floret (1), and no more flowers are produced on this axis, but if another flower exist in the inflorescence it consti- tutes the terminal floret of a new axis (2), similar to the first, and arising from it. And the flower of this new axis expands after that of the central axis, hence the expansion of florets is from above down- wards, or from within outwards, 7.¢. centrifugal. And as each axis has the power of producing only one floret which terminates it, the inflorescence is definite. If more florets exist in this inflorescence, each one terminates an axis which arises in a manner similar to that already described. Thus the number of florets in such an inflores- cence will depend on the number of bracts which are produced upon the several axes, and which give rise to new unifloral axes, Fig. 278 represents such a definite inflorescence, where two bracts are produced on each axis, giving rise to similar new axes ; the whole inflorescence in this case being a biparous cyme. TaBuLaR VIEW OF INFLORESCENCE. A. Indefinite Centripetal Inflorescence. I. Flowers solitary, axillary. Vinca, Veronica hederifolia. II. Flowers in groups, pedicellate. 1. Elongated form (Raceme), Hyacinth, Laburnum, Currant. (Corymb), Ornithogalum. 2. Contracted or shortened form (Umbel), Cowslip, Astrantia. III. Flowers in groups, sessile. 1. Elongated form (Spike), Plantago. (Spikelet), Grasses. ——— (Amentum, Catkin), Willow, Hazel. ——— (Spadix) Arum, some Palms. (Cone), Fir, Spruce. (Strobilus), Hop. 2. Contracted or shortened form (Capitulum), Daisy, Dandelion, Scabious. IV. Compound indefinite inflorescence. . Compound Spike, Rye-grass. Compound Spadix, Palms. Compound Raceme, Astilbe. d. Compound Umbel, Hemiock and most Umbellifere. e. Raceme of Capitula, Petasites, J. Raceme of Umbels, Jvy. B. Definite Centrifugal Inflorescence. I. Flowers solitary, terminal, Gentianella, Peony. soe BRACTS OR FLORAL LEAVES. 189 II. Flowers in Cymes. 1. Uniparous Cyme. u. Helicoid Cyme (axes forming a spiral). * Elongated form, Alstrdmeria. ** Contracted form, Witsenia corymbosa. b. Scorpioid Cyme (axes unilateral, two rows). * Elongated form, Forget-me-not, Symphytum,, Henbane. ** Contracted form, Hrodium, Alchemilla arvensis. 2. Biparous Cyme (Dichotomous), including 3-5-chotomous Cymes, a. Elongated form, Cerastium, Stellaria. b. Contracted form (Verticillaster), Dead-nettle, Pelargonium. 8. Compound Definite Inflorescence. Streptocarpus polyanthus, many Calceolarias, C. Mixed Inflorescence. 1. Raceme of Scorpioid Cymes, Horse-chestnut. 2. Scorpioid Cyme of Capitula, Vernonia centriflora. 8. Compound Umbel of Dichotomous Cymes, Lauwrustinus. 4, Capitulum of contracted Scorpioid Cymes (Glomerulus), Sea-pink. Fe 2.—Bracts or Floral Leaves. Flowers arise from the axil of leaves, called Bractew, bracts or floral leaves, The term bract is properly applied to the leaf, from which the primary floral axis, whether simple or branched, arises, while the leaves which arise on the axis between the bract and the outer envelope of the flower are bracteoles or bractlets. Bracts some- times do not differ from the ordinary leaves, and are then called leafy, as in Veronica hederifolia, Vinca, Anagallis, and Ajuga. Like leaves, they are entire or divided. In general, as regards their form and appearance, they differ from ordinary leaves, the difference being greater in the upper than in the lower branches of an inflorescence. They are distinguished by their position at the base of the flower or flower-stalk. Their phyllotaxis is similar to that of the leaf. When the flower is sessile the bracts are often applied closely to the calyx, and may thus be confounded with it, as in Malvaceze and Rosacez, where they have received the name of epicaly« (p. 198). In many cases bracts seem to perform the function of protecting organs, within or beneath which the young flowers are covered in their earliest stage of growth. When bracts become coloured, as in Amherstia nobilis, Euphorbia splendens, Erica elegans, and, Salvia splendens, they may be mistaken for parts of the corolla, They are sometimes mere scales dt threads, and at other times they are abortive, and remain undeveloped, giving rise to the ebracteated inflorescence of Cruciferze and some Boraginacee. Sometimes no flower-buds are produced in their axil, and then they are empty, A series of empty coloured bracts terminates the inflores- cence of Salvia Horminum. The smaller bracts or bracteoles, which occur among the subdivisions of a branching inflorescence, often produce no flower-buds,, and thus anomalies occur in the floral arrangements, _ 190 BRACTS OR FLORAL LEAVES. Bracts are occasionally persistent, remaining long attached to the base of the peduncles, but more usually they are deciduous, falling off early by an articulation. In some instances they form part of the fruit, becoming incorporated with other organs. Thus, the cones of Firs (figs. 217, 218) and the strobili of the Hop are composed of a series of bracts arranged in a spiral manner, and covering fertile flowers ; and the scales on the fruit of the Pine-apple (fig. 280 a) are of the same nature. In Amenta or catkins (fig. . 259) the bracts are called squame or scales, As regards their arrangement, they follow the same law as leaves; being alternate, opposite, or verticillate. At the base of the general umbel in umbelliferous plants, a whorl of bracts often exists, called a general involucre (fig. 262 7’), and at the base of the smaller umbels or umbellules there is a similar leafy whorl called involucel or partial involucre (fig. 2627”). In Composite, the name involucre is applied to the leaves, scales, or phyllaries, surrounding the head of flowers (fig. 263 b), as in Dandelion, Daisy, Artichoke. This involucre is frequently composed of several rows of leaflets, which are either of the same or of different forms and lengths, and often lie over each other in an im- bricated manner. When the bracts are arranged in two rows, and the outer row is perceptibly smaller than the inner, the involucre is sometimes said to be caliculate, as in Senecio. The leaves of the in- volucre are spiny in Thistles and in Dipsacus (fig. 265, e «), and hooked in Burdock. Such whorled or verticillate bracts may either remain separate (polyphyllous), or may be united by cohesion (gamophyllous), as in many species of Bupleurum, and in Lavatera. In the acorn they form the cupula or cup (fig. 281, c), and they also form the husky covering of the Hazel-nut. In the yew the bracts form a succulent covering of the seed. When bracts become united together, and overlie each other in several rows, it often happens that the outer ones do not produce flowers, that is, are empty or sterile. In the artichoke, the outer imbricated scales or bracts are in this condition, and it is from the membranous white scales or bracts (palew) forming the choke attached Fig. 280. Fig. 280. Fruit of Pine-apple (Ananassa sativa), composed of numerous flowers united into one mass ; the scales, a, being modified bracts or floral leaves. The crown, 0, consists of a prolongation of the axis bearing leaves, which may be considered as a series of empty bracts, i.e. bracts not producing flowers in their axil. THE PARTS OF THE FLOWER. 191 to the edible receptacle, that the flowers are produced. The sterile bracts of the Daisy occasionally produce capitula, and give rise to the Hen-and-Chickens Daisy. In place of de- veloping flower-buds, bracts may, in certain circumstances, as in proliferous or viviparous plants, produce leaf-buds. A sheathing bract enclosing one or several flowers is called a spatha or spathe. It is com- mon among Monocotyledons, as Narcissus, Snow- flake, Arum (fig. 260 5), and Palms. In some Palms it is 20 feet long, and encloses 200,000 flowers. Itis often associated with the spadix, and may be coloured, as in Richardia zthiopica, sometimes called the Aithiopian or Trumpet lily. When the spadix is compound or branching, as in Palms, there are smaller spathes, sur- rounding separate parts of the inflorescence, to which the name spathella has sometimes been given. The spathe protects the flowers in their young state, and often falls off after they are developed, or hangs down in a withered form, as in some Palms, Typha, and Pothos, In grasses the outer scales of the spikelets have been considered as sterile bracts, and have received the name of glumes; and in Cyperacez: bracts enclose the organs of reproduction. Fig. 281. 3.—The Flower and its Appendages, The Flower consists of whorled leaves placed on an axis, the internodes of which are not developed. This shortened axis is the Thalamus or torus, There are usually four of these whorls or verticils:—1. The calyx, the outer one. 2. The corolla, 3, The stamens, 4, The most internal one, the pisti, Each of these consists normally of several parts, which, like leaves, follow a law of alternation. Thus, the flower of Crassula rubens (fig. 282) presents a calyx, cc, composed of five equal parts arranged in a whorl; a corolla, p », also of five parts, placed in a whorl within the former, and occupying the intervals be- Fig. 282. tween the five parts of the calyx; five stamens, ¢¢ ¢, in the space between the parts of the corolla, and consequently opposite those of the calyx ; and five parts of the pistil, o 0, which follow the same law ‘Fig. 281, Acorn, or Fruit of the Oak. v, Cupula or cup, formed by the union of numerous bracts or floral leaves, the free points of which are seen arranged ina spiral manner. Fig. 282. Flower of Crassula rubens. ¢c, Foliola of calyx or sepals. p, p, Petals. ee, Stamens, 00, Carpels, each of them having a small scale-like appendage, a, at their base. 192 FLORAL ENVELOPES. of arrangement, Again, in Scilla italica, the parts are arranged in sets of three in place of "five, as shown in fig. 283, where p' p’ p’ are three parts of the external whorl ; iP pp", three of the next whorl ; ¢’, an outer row of stamens; e”, an inner row ; 0, the pistil formed of three parts. It is distinctly seen in these instances that the parts of the flower are to be regarded as leaves arranged on a depressed or shortened axis. When all the parts of the flower are separate, and normally de- veloped, there is no difficulty in tracing this arrangement; but in many cases it is by no means an easy matter to do so, on account of changes produced by the union of one part to another, by degeneration, by the abortion or non-development of some portions, and by the multiplication or folding of others, Of the four whorls noticed, the two outer (calyx and corolla) are called floral envelopes ; the two inner (stamens and pistil) are called essential organs, When both calyx and corolla are present, the plants are Dichlamydeous (dis, twice, BIg: 288; and yAauds, a covering); occasionally one or both become abortive, and then the flower is either Mono- chiamydeous (w6vos, single), having a calyx only, or Achlamydeous (a, privative) or naked, having only the essential organs, and no floral envelope. The Frorat ENVELOPES consist of the calyx and corolla, In most cases, especially in Di- cotyledons, these two whorls are easily distinguishable, the first being external and green, the latter internal, and more or less highly coloured. If there is only one whorl, then, what- ever its colour or degree of de- velopment, it is the calyx. Some- times, as in many Monocotyledons, the calyx and corolla both display Fig. 283, Flower of Beilla italica. -p’ p’p', Three external leaflets, or divisions of the Perianth or Perigone. pp” p” p’, The three internal leaflets. ¢’, Stamens, opposite to the first or external leaflets. ¢’, Stamens, opposite the second or internal leaflets. 0, Ovaries united together into one. s, Three styles, consolidated so as to form one. Fig. 284. Flower of White Lily (Liliwm album). p, Perianth or Perigone, having three parts exterior, pe, alternating with three interior, pi. e, Stamens, having versatile anthers attached to the top of the filaments. s, Stigma at the apex of the style. . FLOWER-BUD—ZSTIVATION. 193 rich colouring, and are apt to be confounded. In such cases, the term Perianth (weg, around, édvbos, flower), or Perigone (egi, and youn, pistil) has been applied to avoid ambiguity. Thus, in the Tulip, Crocus, Lily, Hyacinth, authors speak of the parts of the perianth, in place of calyx and corolla, although in these plants, an outer whorl (calyx) may be detected, of three parts, and an inner (corolla), of a similar number, alternating with them. Thus, the perianth of the white Lily (Lilium album, fig. 284 ) consists ‘of three outer parts, pe, alternating with three internal parts, pi, surrounding the essential organs, g, the stamens, and s, the pistil. The ‘term perianth is usually confined to the flowers of Mono- cotyledons, whatever colour they present, whether green, as in Aspa- ragus, or coloured, as in Tulip, Some use the term perianth as a general one, and restrict the use of perigone to cases where a pistil ‘only is present. In some plants, as Nymphea alba (fig. 342), it is not easy to say where the calyx ends and the corolla begins ; as these two whorls pass insensibly into each other. FLoWER-BUD.—To the flower-bud, the name alabastrus (meaning rose-bud) is sometimes given, and its period of opening has been called anthesis (&vénoic, flower opening), whilst the manner in which the parts are arranged with respect to each other before opening is the estivation (estivus, belonging to summer), or prefloration (pre, before, and flos, flower). The latter terms are applied to the flower-bud in the same way as vernation is to the leaf-bud, and distinctive names have been given to the different arrangements exhibited, both by the leaves individually and in their relations to each other. Thus the sepals and petals may be conduplicate, or they may be rolled outwards or inwards in various ways, or may be folded transversely, becoming crumpled or corrugated, as in the poppy. When the parts of a whorl are placed in an exact circle, and are applied to each other by their edges only, without overlapping or being. folded, thus resembling the valves of a seed-vessel, the zestivation is valvate, as in the calyx of Guazuma ulmifolia (fig. 285 c). The edges of each of the parts may be turned either inwards or outwards; in the former case, the zstiva tion is induplicate, as in the corolla of Guazuma ulmifolia (fig. 285 _p), in the latter: reduplicate, as in the calyx of Althza rosea (figs. 286 c, 287 c). When the parts of a single whorl are placed in a circle, "each of them exhibiting a torsion of its axis, so that by one ol’ its sides it overlaps its neighbour, whilst its side is overlapped in like manner by that standing next to it, the estivation is twisted or contortéve, as in the corolla of Althea rosea (figs. 286 p, 288 p). This arrangement is characteristic of the flower-buds of Malvaceze and Apocynaces, and it is also seen in Convolvulaceze and some Caryo- phyllaceez. When the flower expands, the traces of twisting often disappear, but sometimes, as.in Apocynacex, they remain. 0 194 FLOWER-BUD—ASTIVATION. In these instances of zstivation, the parts of the verticils are con- sidered as being placed regularly in a circle, and about the same height, Fig. 285. Fig. 286. Fig. 287. Fig. 288. and they are included under circular estivation.. But there are other cases in which there is a slight difference of level, and then the true spiral a ae exhibits itself. This is well seen in the leaves of the calyx of Camellia japonica (fig. 289 c), which cover each other partially like tiles on a a house. This estivation is imbricate. At other times, as in the petals of Camellia (fig. 289 p), the parts envelop each other completely, so as to become convolute. This is also seen in a transverse section of the calyx of Magnolia grandiflora (fig. 291), where each of the three leaves embraces that within it. When the parts of a whorl are five, as occurs in many Dicotyledons, and the imbrication is such that there are two parts external, two internal, and a fifth which partially covers one of the internal parts by its margin, and is in its turn partially covered by one of the external parts, the estivation is quincuncial (fig. 290). This quincunx is com- mon in the corolla of Rosacex. Fig. 290 is a transverse section of the calyx in the flower-bud of Convolvulus sepium, in which the parts are numbered according to their arrangement in the spiral cycle, and the course of the spiral is indicated by dotted lines. In fig. 292, a section is given of the bud of Antirrhinum majus, showing the imbri- cate spiral arrangement. In this case it will be seen, when contrasted Fig. 289. Fig. 285. Diagram of calyx, c, and corolla, p, in the bud of Guazuma ulmifolia. istiva- tion of calyx valvate, of petals induplicate. Fig. 286. Diagram of calyx, c, and corolla, p, in the flower-bud of Althea rosea. Astivation of calyx reduplicate, of petals contortive or twisted. Fig. 287. Flower-bud of Althea rosea in a young state, showing calyx, ¢, still completely enveloping the other parts, and the edges of its divisions touching each other. Fig. 288, The same in a more advanced state, where the calycine divisions, c, are separated so as to allow the expansion of the corolla, the petals of which, p, are contortive in estivation. Fig. 289. Flower-bud of Camellia japonica. c, Imbricated sepals of the calyx. yp, Petals with convolute estivation. FLORAL ENVELOPES—CALYX, 195 with fig. 290 that the part marked 2 has, by a slight change in posi- tion, become overlapped by 4. In flowers, such as those of the Pea (p. 205, fig. 316), one of the or 2 parts, the vexillum, is often é “\ 5 . large and folded over the : Wt \ CO “\ others, giving rise to vewillary * yi, « yy Nise ncor JF 3 ~—” estivation, or the carina may “ax perform a similar office, and ‘ : then the estivation is carinal, Mig. 200. Fig. 291. Fig. 292. The several verticils often differ in their mode of estivation. Thus, in Malvacee, the corolla is contortive and the calyx valvate, or reduplicate (fig. 288); in St. Johns-wort the calyx is imbricate, and the corolla contortive. In Convolvulacez, while the corolla is twisted, and has its parts arranged in a circle, the calyx is imbricate and exhibits a spiral arrangement (fig. 290). In Guazuma (fig. 285), the calyx is valvate, and the corolla induplicate. The circular estivation is generally associated with a regular calyx and corolla ; while the spiral estivations are connected with irregular as well as regular forms. The different parts of the flower, besides having a certain position as regards each other, bear also definite relations to the floral axis whence they arise. An individual part of a flower may be turned to one or other side of the axis, to the right or to the left. This law often holds good with whole groups of plants,'and a means is thus given of characterising them. If a whorl of the flower consists of four} parts, that which is turned towards the floral axis is called superior or posterior, that next the bract whence the pedicel arises is inferior or anterior, while the other two are lateral. If, again, there are five parts of the whorl, then two may be inferior, two lateral, and one superior, as in the corolla of the Pea tribe; or one may be in- ferior and two superior, as in the corolla of the Rose tribe. In plants having blossoms like the Pea, the vexillum, or odd petal, is the superior part ; whilst in the calyx the odd part, by the law of alter- nation, is inferior. Sometimes the twisting of a part makes a change in the position of other parts, as ‘in orchids, where the twisting of the ovary changes the position of the labellum. External Floral Whorls, or Floral Envelopes, Catyx.—The calyx is the external envelope of the flower, and consists of verticillate leaves, called sepals, foliola or phylla (foliwm, Fig. 290. Transverse section of calyx in flower-bud of Convolvulus sepium. Calyx con- sists of five sepals corresponding to the numbers in the figure, and the dotted lines indicate the direction of the spiral according to which they are arranged. Fig. 291. Transverse section of the bud of Magnolia grandiflora, showing the convolute estivation of the three outer leaflets (calyx). Fig. 292, Arrangement of the parts of the calyx in the flower of Frogsmouth (Antirrhinum majus). The arrangement differs from that in fig. 290, on ac- count of a slight twisting and overlapping of the parts. 196 FLORAL ENVELOPES—CALYX. and giA)ov, a leaf). These calycine leaves are sometimes separate from each other, at other times they are united to a greater or less ex- tent; in the former case, the calyx is dialysepalous (d:addverv, to divide), polysepalous or polyphyllous (woAvs, many); in the latter, gamosepalous or gamophyllous, monosepalous or monophyllous (ydmos, union, sudvos, one). The divisions of the calyx present usually all the characters of leaves, and in some cases of monstrosity they are converted into the ordinary leaves of the plant. This is frequently seen in the Rose (fig. 247 c, p. 172), Peony, etc. Their structure consists of cellular tissue or parenchyma, traversed by vascular bundles, in the form of ribs and veins, containing spiral vessels, which can be unrolled, deli- cate woody fibres, and other vessels,—the whole being enclosed in an epidermal covering, having stomata and often hairs on its outer sur- face, which corresponds to the under side of the leaf. In the great divisions of the vegetable kingdom, the venation of the calyx is similar to that of the leaves ; parallel in Monocotyledons, reticulated in Dicotyledons. The leaves of the calyx are usually entire (fig. 293), but occasionally they are cut in various ways, as in the Rose (fig. 294 cf), and they are sometimes hooked at the margin, as in Rumex uncatus (fig. 295 ci). In the last-named plant there Fig. 293. Fig. 204, Fig. 295. are two whorls of calycine leaves, the outer of which, ce, are entire, while the sepals of the inner whorl have hooked margins and have also swellings, gy, in the form of grains or tubercles on the back. The outer leaves, ce, may be looked upon in this case as bracts, occupying an intermediate place between leaves and sepals. It is rare to find Fig. 293. Pentaphyllous or pentasepalous calyx of Stellaria Holostea; sepals entire. Fig. 294. Flower of Rose, cut vertically. ct, Tube of the calyx. of, Limb of calyx divided into leaflets. ee, Stamens. oo, Ovaries, each having a style which reaches beyond the tube of the calyx, and ends in a stigma, s. vr, Receptacle. Fig. 295. Calyx of Rumex uncatus, composed of two verticils or whorls; the outer, ce, having short and entire divisions ; the inner, ci, having larger divisions, which exhibit at the margin narrow hooked projections, and have on the back a tubercular swelling, g. FLORAL ENVELOPES—CALYX. 197 the leaves of the calyx stalked. They are usually sessile leaves, in which the laminar portion is only slightly developed, and frequently the vaginal part is alone present. Sepals are generally of a more or less oval, elliptical, or oblong form, with the extremity either blunt or acute. In their direction they are erect or reflexed (with their apices downwards), spreading outwards (divergent or patulous), or arched in- wards (connivent). They are usually of a greenish colour, and are called foliaceous or herbaceous; but sometimes they are coloured,. as in the Fuchsia, Tropzolum, Globe-flower, and Pomegranate, and are then called petaloid. Whatever be its colour, the external envelope of the flower must be considered as the calyx. The nature of the hairs on the calyx gives rise to terms similar to those already mentioned as applied to the surfaces of other parts of plants (p. 33). The vascular bundles sometimes have a promi- nent rib (figs. 296, 297), which indicates the middle of the sepal, at other times they have several ribs (fig. 298). Thevenation is use- ful as pointing out the number of leaves which form a gamosepalous calyx. At the part where two sepals unite, there is occasionally 297. Fig. 298, a prominent line, formed by the union of the vessels of each (fig. 298), which divides near the apex into two branches, each following the course of their respective sepals. In a polysepalous calyx, the number of the parts is marked by Greek numerals prefixed. Thus, a trisepalous calyx has three sepals, pentasepalous or pentaphyllous, five, as in Stellaria Holostea (fig. 293), and soon. The sepals occasionally are of different forms and sizes. In Aconite, one of them is shaped like a helmet, and has been called galeate (gale, a helmet). In Calcophyllum one of the sepals en- larges after the corolla falls, and assumes a pink colour. In Clero- dendron Thomsonz the white calyx becomes pinkish after the scarlet corolla withers. In a gamosepalous calyx the sepals adhere in various ways, some- times very slightly, as in Ginothera ; and their number is marked by the divisions at the apex. These divisions are either simple projections in the form of acute or obtuse teeth (fig. 297); or they extend down the calyx as fissures about half-way, the calyx being trifid (three-cleft), quinquefid (five-cleft), as in Primula elatior (fig. 296), according to their number ; or they reach to near the base in the form of partitions, Fig. 296. Quinquefid or five-cleft calyx of Primula elatior, the oxlip. Fig. 297. Five- toothed inflated calyx of Silene inflata. Fig. 298. Calyx, c, of Hibiscus, with its caliculus or epicalyx, b. / 198 FLORAL ENVELOPES—CALYX. the calyx being tripartite, quadripartite, quinguepartite, etc. The adhesion or union of the parts may be complete, and the calyx may be quite entire or truncate, as in some Correas, the venation being the chief indication of the different parts. The adhesion is sometimes irregular, some parts uniting to a greater extent than others ; thus a two-lipped or dabiate calyx is formed, which, when the upper or posterior lip is arched, becomes ringent. The upper lip is often com- posed of three parts, which are thus posterior or next the axis, while the lower has two, which are anterior. The part formed by the union of the sepals is called the tube of the calyx ; the portion where the sepals are free is the limb. Sometimes a gamosepalous calyx assumes an angular or prismatic form, as in Lamium and Primula, and then the angles are marked by the midribs of the sepals which form it. Occasionally the calyx has a globular form, as in the globe- flower, at other times it is bell-shaped, funnel-shaped, turbinate (like a top), or inflated as in Silene inflata (fig. 297). Occasionally, certain parts of the sepals undergo marked enlargement. In the Violet, the calycine segments (lacinia) are prolonged downwards beyond their inser- tions, and in the Indian Cress (Tropzolum) this prolongation is in the form of a spur (calcar), formed by three sepals (fig. 299 e) ; in Delphinium it is formed by one. When one or more sepals are thus enlarged, the calyx is calcarate or spurred, In Pelar- gonium the spur from one of the sepals is adherent to the flower-stalk. In some plants, as in the Mallow tribe, the flower appears to be provided with a double calyx, which has been denominated caliculate, the outer calyx being the epicalyx. In fig. 298, ¢ represents the calyx of Hibiscus, and b the smaller calyx or epicalyx outside ; and in fig. 300, the same thing is shown in Potentilla verna. Many authors look upon this epicalyx as a collection of whorled bractlets, forming an involucre immedi- ately below the flower. In some cases the project- ing teeth between the divisions of the calyx, as in Rosacez, are to be traced to the transformed stipules of the calycine leaves. Degenerations take place in the calyx, so that it becomes dry, scaly, and glumaceous (like the glumes of grasses), as in Fig. 300. the Rush tribe ; hairy, as in Compositz ; or a mere rim, as in some Umbelliferse and Acanthacez, when it is called obsolete or marginate. Fig. 299. Fig. 299. Calcarate calyx of Tropzolum, Indian cress. e, Spur or calcar. , Pedicel. Fig. 300. Calyx, cc, of Potentilla verna, with its epicalyx or caliculus, 0 b. FLORAL ENVELOPES—CALYX. 199 In Composite, Dipsacaces, and Valerianaces, the calyx is at- tached to the pistil, and its limb is developed in the form of hairs, called pappus. This pappus is either simple (pilose) (fig. 302), or feathery (plumose) (fig. 303). In cases where, to the naked eye, the hairs appear to be simple, the examination by a lens sometimes exhibits distinct tooth-like projections often irregularly scattered. In figs. 301, 302, 303, there are examples of calyces, c, which are attached to the pistil, while their limbs, 7, show the transition from the narrowed thread-like form in Catananche cerulea (fig. 301) to the pilose in Scabiosa atro-purpurea (fig. 302), and thence to the plumose in Pterocephalus palestinus (fig. 303). In Valeriana the superior calyx is at first an obsolete rim, but as the fruit ripens, it is shown to consist of hairs rolled inwards, which expand so as to waft the fruit. Fig. 301. Fig. 303, The calyx sometimes falls off before the flower expands, as in Poppies, and is caducous; or along with the corolla, as in Ranunculus, and is deciduous ; or it remains after flowering, as in Labiatz, Scrophu- lariaceze, and Boraginacee ; or its base only is persistent, as in Datura Stramonium. In Eschscholtzia and Eucalyptus the sepals remain united at the upper part, and become disarticulated at the base or middle, so as to come off in the form of a lid or funnel. Such a calyx is operculate (operculum, a lid), or calyptrate (xaAlarea, a cover- ing). The existence or non-existence of an articulation determines the deciduous or persistent nature of the calyx. In the case of Esch- scholtzia the axis seems to be prolonged so as to form a sort of tube, from which the calyx separates. In Eucalyptus the calyx consists of leaves, the laminze or petioles of which are articulated like those of Figs. 301-303, Examples of calyces, the limbs of which, J, gradually pass into the state of hairs or pappus. ct, Calyx, united to the ovary, and forming a narrow column above it ; in figs. 302, 303, the calyx ends in numerous simple or feathery hairs, J. 4, Involucre or gamosepalous bracts cut vertically. Fig. 301. Calyx of Catananche cerulea. _Fig. 302. Calyx of Scabiosa atro-purpurea. Fig. 303, Calyx of Pterocephalus palestinus, 200 FLORAL ENVELOPES—COROLLA. the Orange, and the separation between the parts occurs at this articulation. The receptacle bearing the calyx is sometimes united to the pistil, and enlarges, so as to form a part of the fruit, as in the Apple, Pear, Pomegranate, Gooseberry, etc. In these fruits the withered calyx is seen at the apex. Sometimes a persistent calyx increases much after flowering, and encloses the fruit, without being incorporated with it, becoming accrescent (accresco, I increase), as in various species of Physalis (fig. 304); at other times it remains in a withered or marcescent (marcesco, I decay) form, as in Erica ; sometimes it becomes inflated or vesi- cular, as in sea campion. In Trifolium fra- giferum the union of the inflated calyces produces the strawberry-like appearance of the head of flowers when in fruit. Corotta.—The corolla is the more or less coloured inner floral envelope, forming the whorl of leaves between the calyx and the stamens. It is generally the most con- spicuous whorl, The gay colours and fra- grant odours of flowers are resident init. It is present in the greater number of Dicoty- ledons. It is composed of parts which are Fig. 804. usually disposed in one or more verticillate rows, and which are called petals (rérarov, a leaf). The petals some- times form a continuous spiral with the calycine segments, but in general they are disposed in a circle, and alternate with the sepals. Petals differ more from leaves than sepals do, and are much more nearly allied to the staminal whorl. In some cases, how- ever, they are transformed into leaves, like the calyx, and occasionally leaf-buds are developed in their axil. They are seldom green, although occasionally this colour is met with, as in some Cobeas, Hoya viridi- flora, Gonolobus viridiflorus, and Pentatropis spiralis. As a rule they are highly coloured, the colouring matter being contained in cells, and differing in its nature from the chlorophyll of the leaves. As regards their structure, petals consist of cellular tissue traversed by true spiral vessels, and thin-walled tubes. In delicate flowers, as Convol- vulus and Anagallis, these vessels are easily seen under the microscope. Petals do not usually present numerous layers of cells like the leaves, neither is the epidermis always distinct, although in some instances it may be detached, especially from the surface next the calyx. The cuticle of the petal of a Pelargonium, when viewed with a 4 or 4 inch object glass, shows beautiful hexagons, the boundaries of which are ornamented with several inflected loops in the sides of the cells. Fig. 304. Accrescent calyx, c, connected with the fruit of Physalis Alkekengi. FLORAL ENVELOPES—COROLLA. 201 On the outer surface of petals, corresponding to the lower side of leaves, stomata are sometimes found. Petals are generally glabrous or smooth ; but, in some instances, hairs are produced on their surface. Petaline hairs, though sparse and scattered, present occasionally the same arrangement as those which occur on the leaves: thus in Bom- bacez they are stellate. Coloured hairs are seen on the petals of Menyanthes, and on the segments of the perianth of the Iris. Although petals are usually very thin and delicate in their texture, they occasionally become thick and fleshy, as in Stapelia and Rafflesia ; or dry, asin Heaths; or hard and stiff, as in Xylopia. A petal often consists of two portions—the lower narrow, resembling the petiole of a leaf, and called the unguis or claw ; the upper broader, like the blade of a leaf, and called the lamina or limb. These parts are seen in the petals of the Pink (fig. 305), where o is the claw, and 1 Fig. 805. the limb. The claw is often wanting, as in the Rose, and the petals are then sessile. Petals having a claw are unguiculate, Petals, properly so called, belong to Dicotyledonous plants, for in Monocotyledonous the flowers consist of a perianth or perigone, which is referred to the calycine envelope. Hence the venation of petals resembles that of the leaves of Dicotyledons. In the claw the vessels are approximated, as in the petiole, and in the limb they expand. There may be a median vein whence lateral veins go off, at the same or different heights, forming reticulations; or there may be several primary veins diverging from the base of the limb, and forming a sort of fan-shaped venation. At other times the median vein divides into two. According to the development of veins, and the growth of cellular tissue, petals present varieties similar to those already noticed in the case of leaves, Thus the margin is either entire or divided into lobes or teeth. These teeth sometimes form a regular fringe round the margin, and the petal be- comes fimbriated (fimbria, a fringe), as in the Pink (fig. 305); or laciniated, as in Lychnis Flos-cuculi ; or crested, as in Poly- gala. Sometimes the petal becomes pinna- tifid, as in Schizopetalum. The median Fig. 806. Fig. 807. vein is occasionally prolonged beyond the Fig. 305. An unguiculate petal of Dianthus monspessulanus. o, Unguis or claw. 1, Limb, which is fimbriated, or has a fringed margin. Fig. 306, A petal of Eryngium campestre, with the apex inflexed or turned down towards the base. __ Fig. 807. A bipartite petal of Stellaria media, or common Chickweed. 1, The limb split into two. 0, The claw. 202 FLORAL ENVELOPES—COROLLA. summit of the petals in the form of a long process, as in Strophanthus hispidus, where it extends for seven inches ; and at other times it ends in a free point or cuspis, and the petal becomes cuspidate ; or the pro- longed extremity is folded downwards or inflexed, as in Umbelliferee (fig. 306), so that the apex approaches the base. If the median vein divides into two, the space between. the divisions may be filled up so as to leave only a slight deficiency, and thus the petal becomes emarginate ; or the deficiency may be greater, while the limb gradually expands from below upwards, and its extremity becomes two-lobed, so that the petal is obcordate, If the separation extends to the middle, it is bifid; if to near the base, bipartite, as in Chickweed (fig. 307 1). In the same way as in leaves, the venation of the petals is sometimes unequal, and the cellular tissue is developed more on one side than on the other, thus giving rise to an oblique petal. The limb of the petal may be flat or concave, or hollowed like a boat, cymbiform or navicular (cymba, a boat, navis, a ship), or like a spoon, cochleartform (cochleare, a spoon). In the case of the navicular petal, the median vein forms a marked keel. In Hellebore the petals become folded in a tubular form, resembling a horn; in Aconite (fig. 308) some of the petals, p, resemble a hollow curved horn, supported on a grooved stalk ; while in Colum- bine (fig. 309) Violet, Snap- dragon, and Centranthus, one or all of them are prolonged in the form of a spur, and are calcarate (calcar, a spur). In Valeriana, Antirrhinum, and Corydalis, the spur is very short, and the corolla or petal is said to be gibbous (gibbus, a bunch or swelling), or saccate at the base. In some Bora- ginacee (fig. 322) there are foldings at the upper part of the tube of the corolla, 7, forming projections concave outwardly, which might be considered as small internal spurs. When a petal is narrow throughout, as if formed by a prolongation Fig. 308. Fig. 310. Fig. 308. Part of the flower of Aconitum Napellus, showing two irregular horn-like petals, p, supported on grooved stalks, 0. These used to be called nectaries, s, The whorl of stamens inserted on the thalamus, and surrounding the pistil. Fig. 309. Single spurred petal of Aquilegia vulgaris, common Columbine, formed by a folding of the margins. Fig. 310. Cordate or cordiform petal of Genista candicans, v, The claw. 1, The limb. i a FLORAL ENVELOPES—COROLLA. 203 of the claw, it is called linear ; when the limb is prolonged at the base, so as to form two rounded lobes, it is cordate, as in the petal of Genista candicans (fig. 310) ; and when the lobes are acute, it may be sagittate or hastate. The meaning of the terms indicating the forms of petals will be understood by considering those applied to leaves. As arule, the terms refer to the limb of the petal, which is frequently the only portion developed. In the Poppy, the petals have a puckered or corrugated appearance, arising from their delicacy, and the mode in which they are folded in eestivation. Other petals have a crisp or wavy margin. A corolla rarely consists of one petal, and when this occurs, as in Amorpha, it depends on the abortion or non-development of others. Such a corolla is unipetalous (unus, one), a term quite distinct from monopetalous. In general, the corolla consists of several petals, equal- ling the sepals in number, or being some multiple of them. When this is the case, the floral envelopes are said to be symmetrical ; when, however, by the abortion of some of the petals the numbers do not correspond, then the flower becomes unsymmetrical. Under the head of floral symmetry the various changes consequent on non-development of petals will ‘be noticed. A corolla is dipetalous, tripetalous, tetra- petalous, or pentapetalous, according as it has two, three, four, or five separate petals, The general name of polypetalous (woAds, many), or dialypetalous (dsaAver, to divide), is given to corollas having separate petals, while monopetalous or gamopetalous (wévos, one, and yawos, union) is applied to those in which the petals are united, This union generally 2 takes place at the base, and extends more or less towards the apex; in Phyteuma the petals are united at their apices also. In some polypetalous corollas, as that of the Vine, the petals are separate at the base, and adhere by their apices. That a monopetal- ous corolla consists of several petals united is shown in such plants as Phlox amena, where some specimens have petals more or less completely disunited, while others ex- hibit the normal form of coherent petals. ; When the petals are equal as regards their e\W development and size, the corolla is regular; _ ” when unequal itis trregular, Even although the separate petals are oblique, still, if they are all equally so, as in oe Fig. 811. Fig. 312. ' Fig. 811. Regular monopetalous or gamopetalous tubular corolla of Spigelia marylandica. ¢, Calyx. t, Tube of the corolla, 1, Limb of the corolla. s, Stigma at the summit of style. Fig. 812. Irregular gamopetalous or monopetalous corolla of Digitalis purpurea, Fox- glove. c, Calyx. y, Corolla. t, Tube. J, Limb. 204. POLYPETALOUS COROLLAS. many Malvacee with twisted zstivation, the corolla is regular. The size of the corolla as compared with the calyx, the number, direction, and form of its parts, and their relation to the axis of the plant, require attention. When a corolla is gamopetalous, it usually happens that the claws are united into a tube (figs. 311 ¢, 312 t), while the upper parts are either free or partially united, so as ‘to form a common limb (fig. 311 1), the two portions being separated by the faux or throat, which often exhibits a distinct constriction or dilatation. The number of parts forming such a corolla can be determined by the divisions, whether existing as teeth, crenations, fissures, or partitions; or if, as rarely Fig. 318. Fig. 314. happens, the corolla is entire, by the venation. The union may be equal among the parts, or some may unite more than others. Some- times the tubular portion is bent, as in Lycopsis ; at other times the limb is curved at its apex, as in Lamium. RecuLaR PoLtyPeTatous CoRoLLas. —Among them may be noticed the rosa- ceous corolla, in which there are five spreading petals, having no claws, and arranged as in the single Rose (fig. 313) and Potentilla; the caryophyllaceous co- rolla, in which there are five petals with long narrow tapering claws, as in many Fig. 313. Polypetalous flower of Rosa rubiginosa, the Sweet-brier. b, Bract or floral leaf. ct, Hollow torus, which forms the conspicuous part of what is commonly called the fruit. ¢f, ef, ef, cf, of, Sepals or foliola of the calyx. pp pp, Petals without a claw. ¢, Stamens attached to the calyx. Fig. 314. Polypetalous flower of Dianthus monspessu- Janus. 6, Bracts. c, Calyx. pp, Petals with their claws, 0, approximated so as to form a tube. Fig. 315. Cruciferous flower of Cheiranthus Cheiri, Wallflower. c, Lobes of the sepals ; the two external sepals being prolonged at the base, so as to form a sort of spur or swelling (gibbous orsaccate). pp, The four petals arranged like a cross. e, The four longer stamens, the summits of the anthers being visible, Fig. 315. GAMOPETALOUS COROLLAS. 205 of the Pink tribe (figs. 305, 314); the alsinaceous, where the claw is less narrow, and there are distinct spaces between the petals, as in some species of Chickweed ; cruciform, having four petals, often un- guiculate, placed opposite in the form of a cross, as seen in Wall- flower (fig. 315), and in other plants called cruciferous (crux, a cross, and fero, I bear), IrrecutaR PotypeTatous Corornas.—The most marked of these is the papilionaceous (fig. 316), in which there are five petals ; one superior (posterior), ¢, placed next to the axis, usually larger than the rest, and folded over them in estivation, called the vexillum or standard ; two lateral, a, the ale or wings ; two inferior (anterior), partially or completely covered by the ale, and often united slightly by their lower margins, so as to form a single keel-like piece, b, called carina, or keel, which embraces the essential organs. This corolla occurs in the Leguminous plants of Britain, or those plants which have flowers like the pea. Among the irregular polypetalous corollas might be included the orchideous (fig. 317), although it is really the perianth of a Monocotyledon. This perianth consists of three outer portions equivalent to the calyx, and three inner parts alternating with them, constituting the petals. The latter are often very irregular, some being spurred, others hooded, etc. ; and there is always one, called the labellum or lip (Fig. 317 2), which pre- sents a remarkable development, and gives rise to many of the anomalous forms exhibited by these flowers. RecuLtsR MonoperaLous on GAMOPETAL- ous CoroLLAs.—These are sometimes campanu- late or bell-shaped, as in Campanula rotundifolia (fig. 318); infundibuliform or funnel-shaped, when the tube is like an inverted cone, and the limb becomes more expanded at the apex, as in Tobacco (fig. 319); hypocrateriform or salver-shaped, when there is a straight tube surmounted by a flat spreading limb, as in Primula (fig. Fig. 316. i Fig. 316. Irregular polypetalous corolla in the papilionaceous flower of Lathyrus odoratus, Sweet-pea, ¢, Calyx. e, Vexillum or standard. a, Two ale or wings. 2, Carina or keel, formed of two petals. Fig. 317. Flower of Twayblade (Listera ovata), seen in front, showing a large bifid labellum, 2, which is different from the other five divisions of the perianth. The divisions of the perianth are in two rows of three each. The essential organs of reproduction are placed on a column opposite the labellum, The perianth is irregular polyphyllous, and is denominated Orchideous, 206 GAMOPETALOUS COROLLAS. 320); tubular, having a long cylindrical tube, appearing continu- ous with the limb, as in Spigelia (fig. 311), and Comfrey (fig. 321) ; rotate or wheel-shaped, when the tube is very short, and the limb flat and spreading, as in Myosotis (fig. 322); when the divisions of the rotate corolla are very acute, as in Galium, it is sometimes called stellate or star-like ; urceolate or wrn-shaped, when there is scarcely any limb, and the tube is narrow at both ends, and expanded in the middle, Fig. 318. Fig. 319. Fig. 320. as in Bell-heath (Erica cinerea) (fig. 323). Some of these forms may become irregular in consequence of certain parts being more developed than others. Thus, in Veronica, the rotate corolla has one division much smaller than the rest, and in Digitalis there is a slightly irregular campanulate corolla (fig. 312), which some have called digitaliform. IgpreGuLaAR MOoNnoPETALoUs 0R GAMOPETALOUS COROLLAS.— Among these may be remarked the labiate or lipped (fig. 324), having two divisions of the limb in the form of what are called labia or lips (the upper one composed usually of two united petals, and the lower of three), separated by a hiatus or gap, 7. In such cases the tube varies in length, and the parts of the calyx follow the reverse order in their union, two sepals being united in the lower lip, and three in the upper. When the upper lip of a labiate corolla is much arched, and the lips separated by a distinct gap, it is called ringent (ringens, grinning). The labiate corolla characterises the natural order Labiatz. In Lobelia Fig. 318, Regular monopetalous or gamopetalous campanulate or bell-shaped corolla of Campanula rotundifolia. ¢, Calyx. 1, Limb of corolla. s, Stigma. Fig. 319. Regular monopetalous or gamopetalous infundibuliform corolla of Nicotiana Tabacum, Tobacco. c, Calyx. 1, Limb of corolla, s, Stigma. Fig. 320. Regular monopetalous or gamo- petalous hypocrateriform corolla of Primula elatior, Oxlip. c, Calyx. /p, Corolla. t, Tube. i, Limb. a, Anthers. Fig. 321. Regular gamopetalous tubular and somewhat bell- shaped corolla of Symphytum officinale, Comfrey. ¢, Calyx. ¢, Tube of corolla. 1, Limb. s, Stigma. 7, External depressed surface of folds, which project into the tube of the corolla, GAMOPETALOUS COROLLAS. 207 there is a labiate corolla, the upper lip of which becomes convex superiorly, and is split to near the base. When the lower lip is Fig. 322, Fig. 323, Fig, 324. Fig. 825, pressed against the upper, so as to leave only a chink or rictus between them, the corolla is said to be personate or mask-like (persona, a mask), as in Frogsmouth (fig. 325), Snapdragon, and some other Scrophu- lariaceze, and the projecting portion, p, of the lower lip is called the palate. In some corollas the two lips become hollowed out in a remarkable manner, as in Calceolaria, assuming a slipper-like appearance, similar to what occurs in the labellum of some Orchids, as Cypripedium. The calceolate (calceolus, a slipper) corolla of Calceolaria may be considered as consisting of two slipper-like lips. When a tubular corolla is split in such a way as to form a strap-like process on one side with several tooth-like projections at its apex, it becomes ligulate (ligula, a little tongue), or strap-shaped (fig. 326). This corolla occurs in many composite plants, as in the florets of Dandelion, Daisy, and Chicory. The number of divisions at the apex Wir ff Vi indicates the number of united petals, some of o\) which, however, may be abortive. Occasionally some of the petals become more united than others, Fig. 326. Fig. 322. Regular gamopetalous rotate corolla of Myosotis palustris, or Forget-me-not. ce, Calyx. yp, Corolla. 1, Folds of the corolla, forming projections at the upper part of the tube, which are opposite to the lobes of the corolla. Fig. 323. Regular gamopetalous urceolate or urn-shaped corolla of Erica cinerea, or cross-leaved Heath. ¢, Calyx. ¢, Tube of corolla, 1, Limb of corolla. 3s, Stigma. Fig. 324. Irregular gamopetalous labiate or lipped corolla of Salvia pratensis. c, Calyx. t, Tube of corolla, 1, Limb, forming two lips, having a gap or hiatus between them. s, Summit of style. Fig. 325. Irregular gamo- petalous personate or mask-like corolla of Antirrhinum majus, or Frogsmouth. ¢, Calyx. t, Tube of corolla, having a gibbosity or swelling, u, at its base. 1, Limb of corolla. g, The faux or mouth closed by a projection of the lower lip, p. Fig. 326. Irregular gamo- petalous ligulate floret of Catananche cerulea. ¢, Calyx, with a quinquefid limb united inferiorly with the ovary, 0. e, Stamens with united sethers: a (synantherous or syngenesious), surrounding the style, s, with its bifid stigma,, 208 FLOWERS OF GRASSES. and then this corolla assumes a bilabcate or two-lipped form, as seen in the division of Composite called Labiatifloree, In Composite there are often two kinds of florets associated in the same head. Thus, in the Daisy there are irregular ligulate white florets on the outside or in the ray, while there are regular tubular yellow florets in the centre or disc. In Scevola and in Honeysuckle the corolla is split down to its base, so as to resemble somewhat the ligulate form. FLowers oF Grasses AND Sep@rs.—lIn these plants, in place of verticillate leaves forming the flower, there are alternate scales or glumes. The flowers of grasses usually occur in spikelets (fig. 327), which consist of one or two glumes, a, covering several flowers, b. The spikelets are associated in spikes or panicles. In Wheat {Fig. 327. Fig. 328. Fig. 329. Fig. 330. these spikelets are arranged alternately along a common rachis, Each spikelet (fig. 327) consists of two empty glumes, a a, having the form represented in figure 328, and enclosing flowers which are composed of scales (paleze or glumellie), delineated in figures 329 and 330—the former being the outer, and the latter the inner pale or glumella—which are placed at different heights in an alternate manner. In the flower of the Oat (fig. 331), after removing the outer pale or glumella, the inner one, pz, is seen with two scales (lodiculz. or squame), sq, at the base, enclosing the essential organs of reproduction. The paleze of grasses are called by some flowering glumes, while hypogynous scales (lodicule) within this are considered as the rudimentary perianth. In Wheat (Triticum) there are two empty glumes, and Fig. 327. A spikelet of Wheat (Triticum), consisting of two glumes, a a, enclosing several flowers, b b, which are composed of two pales (palez) covering the essential organs of repro- duction. The stamens, s, hang out by long slender thread-like filaments. The individual glumes and palez are placed alternately on the floral axis. Fig. 328. One of the glumes of Wheat (Triticum), seen in profile. These glumes are bracts or floral leaves which consti- tute the outer covering of the spikelet. They are placed at different levels, following the law of alternation. The glume is marked with three ribs. Fig. 329, External (outer) palea or glumella of the flower of Wheat. It is a glumaceous scale marked with two ribs on each side of the midrib. Fig. 330, Internal (inner) palea or glumella of the flower of Wheat, It is thinner and more membranous than the outer glumella (flowering glume), its edges are folded inwards and its apex is bifid, 4 COROLLINE APPENDAGES., 209 two flowering glumes. In the Oat (Avena) there are two empty glumes (gluma, a husk), usually three flowering glumes with awns, and two lodicules (Jodicwla, a coverlet), representing the perianth. In Sedges (Carices) the male flowers are borne on scales, and so are the female, as shown in figure 332, in which the scale, s, is placed on one side. Within the scale the female flower is situated, having a peculiar bag-like covering, , termed perigynium. NeEctaRizs AND ANOMALIES IN Prrats.—Certain abnormal appearances occur in the petals of some flowers, which received in former days the name of nectaries. The term nectary was very vaguely applied by Linnzeus to any part of the flower which presented an un- (i Fig. 333. Fig. 834. Fig. 382. usual aspect, as the crown (corona) of Narcissus, the fringes of the Passion-flower, etc. If the name is retained, it ought properly to include only those parts which secrete a honey-like matter, as the glandular depression at the base of the perianth of the Fritillary (fig. 333 r), or on the petal of Ranunculus, or on the stamens of Rutacez. The honey secreted by flowers attracts insects, which, by conveying the pollen to the stigma, effect fertilisation, What have usually, however, Fig. 331. Flower of Oat (Avena sativa), with the two empty glumes, and the outer flower— glume removed. The inner glumella or palea, pi, is seen of a lanceolate form, and bidentate at the apex. The outer glumella has a long twisted geniculate dorsal awn, with two points or bristles at the summit. By removing this gluniella there are seen two scales (lodicule, squamz), sq, with the three stamens and two feathery styles. Fig. 332, Female (pistilli- ferous or pistillate) flower of a Sedge (Carex), with a single glume or scale, s. The pistil is covered by an urceolate glumaceous bag, u, called perigynium. There is one style, st, with three stigmas at its summit. Fig. 333. One of the segments, s, of the perianth of Fritil- laria imperialis, or Crown Imperial, with a pit or depression, 7, at its base, containing honey-like matter. The cavity is coloured differently from the rest of the segment, and it is often called a nectary, or a nectariferous gland. Fig. 334, Petal of Lychnis fulgens, seen on its inner side. 0, Claw. 1, Limb. a, An appendage supposed to be formed_by chorisis, This appendage was called a nectary by old authors. P 210 COROLLINE APPENDAGES. been called nectaries, are mere modifications of some part of the flower, especially of the corolla and stamens, produced either by degeneration or outgrowth, or by a process of dilaméination (dis, separate, and lamina, a blade), or chorisis (xweifw, I separate). This process, called also deduplication, consists in the separation of a layer from the inner side of a petal, either presenting a peculiar form, or resembling the part from which it is derived. The parts thus pro- duced are not alternate with the petals or the segments of the corolla, but opposite to them. In these cases, the petals at the lower part consist of one piece, but where the limb and claw separate, or where the tube ends, the vascular layer splits into two, and thus two lamin are formed, one posteriorly and the other anteriorly. These scales are well seen in Lychnis (fig. 334 a), Silene, Cynoglossum, and Ranun- culus, and may be considered as formed in the same way as the ligule of grasses (fig. 210, p. 99). Corollas having these scaly appendages are sometimes denominated appendiculate. In other cases, as in Cus- cuta and Samolus, the scales are alternate with the petals, and may represent altered stamens. The formation of these scales is referred to under the section of Morphology and Symmetry. The parts formerly called nectaries are mere modifications of the corolla or stamens. Thus the so-called horn-like nectaries under the galeate sepal of Aconite (fig. 308, p. 202), are modified petals, so also are the tubular nectaries of Hellebore. The nectaries of Menyanthes and of Tris consist of hairs developed on the petals. Those of Parnassia (fig. 335 »), and of the Passion-flower, Stapelia, Asclepias, and Canna, are fringes, rays, (( and processes, which are probably modifications of stamens; and some consider the crown of Nar- \ cissus as consisting of a membrane similar to that which unites the stamens in Pancratium. It is sometimes difficult to say whether these nectaries are to be referred to the corolline or to the staminal row. The paraphyses of the Passion-flower, the crown of Narcissus, and the coronet of Stapelia, are referred sometimes to the one and sometimes to the other. In general, they may be said to belong to that series with which they are immediately connected. Some have given names indicating the parts of which they are modi- fications, by prefixing the term para (rage, beside, or close to), using such terms as paracorolla and parastemones. Petals are attached to the axis usually by a narrow base, but P “a \| Fig. 335. Fig. 335. Petal, p, of Parnassia palustris, or grass of Parnassus, with a so-called nectary, n, Which may be an abortive state of some of the stamens, or a process from the petals, surmounted by stalked glands. DEVELOPMENT OF FLORAL ENVELOPES. 211 occasionally the base is larger than the limb, as in the Orange flower. When this attachment takes place by an articulation, the petals fall off either immediately after expansion (caducous), or after fertilisation (deciduous), A corolla which is continuous with the axis and not arti- culated to it, as in Campanula, Heaths, etc., may be persistent, and remain in a withered or marcescent state while the fruit is ripening. A gamopetalous corolla falls off in one piece ; but sometimes the base of the corolla remains persistent, as in Rhinanthus and Orobanche. DEVELOPMENT or FLorat ENvELorPES.—The floral envelopes, when gamosepalous and gamopetalous, first appear in the form of a ring, whence various cellular pro- jections arise, representing the sepals and petals ; when they are polysepalous and polypetalous, the ring is wanting. Even when the parts become ultimately unequal, as in Digitalis (fig. 309), they form equal cellular papille when first developed (fig. 336). Fig, 336. Irregular flowers may be referred to regular types, from which they seem to have degenerated. There appear to be three principal kinds of irregularity among corollas:—1l. Irregularity by simple in- equality in the development of the several segments, often along with ad- hesion or atrophy, or arrest of growth: this is the most common kind. 2. Irregularity of deviation, when the segments, though equal, turn all to the same side, as in ligulate florets, 3. Irregularity by simple meta- morphosis of stamens, as in Canna. The irregular corollas of Acan- thaceze, Bignoniaceze, Gesneracese, Lobeliaceze, and Scrophulariacez, are formed at first in a regular manner, by equal projections from a sort of cup or ring. In Calceolaria, there is at first a scooped-out cup, with four regular and very minute teeth, which are ultimately de- veloped asthe corolla; the nascent calyx has also four divisions. In Begoniacez the floral envelope at first appears as a continuous ring, having five equal small segments; some of these, especially in the male flowers, disappear entirely or become atrophied. Inner Floral Whorls, or the Essential Organs of Reproduction, These organs are the stamens and the pistil, the latter containing the seeds or germs of young plants, and corresponding to the female, while the former produces a powder necessary for fecundation, and is looked upon as performing the part of the male. The presence of both is required in order that perfect seed may be produced. A flower may have a calyx and corolla, and yet be imperfect if the essential Fig. 336. Bud of the irregular gamopetalous flower of Digitalis purpurea. cc, Calyx. p, Corolla, which in its early development is regular. ¢, The stamens, at first projecting beyond the corolla. 212 ESSENTIAL ORGANS—STAMENS. organs are not present. The name of hermaphrodite or bisexual is given to flowers in which both these organs are found; that of wnt sexual (one sex), or diclinous (dis, twice, and Aivq, a bed), to those in which only one of these organs appears,—those bearing stamens only being. staminiferous (stamen, a stamen, fero, I bear), or male ; those having the pistil only, pistilliferous (pistillum, a pistil, fero, I bear), or female. The absence of one of the organs is due to abortion or non-develop- ment, When in the same plant there are unisexual flowers, both male and female, the plant is said to be monectous or monoicous (wévos, one, and oizioy, habitation), as in the Hazel and Castor-oil plant; when the male and female flowers of a species are found on separate plants, the term diwctous or dioicous (dis, twice) is’ applied, as in Mercurialis and Hemp; and when a species has male, female, and hermaphrodite flowers on the same or different plants, as in Parietaria, it is poly- gamous (wor0c, many, and yéwoc, marriage). The term agamous (a, privative, and yéwoc, marriage) has sometimes been applied to Crypto- gamic plants, from the supposed absence of any bodies truly represent- ing the stamens and pistil. Flowers of the same species of plant sometimes present different forms as regards stamens and pistil. Thus, in the same species of Primula and Linum there are differences in the size and development of the stamens and pistil, one flower having long stamens and a pistil with a short style, the other having short stamens and a pistil with a long style. The former occur in what are called thumb-eyed prim- roses, the latter in those called pin-eyed. Such plants are called dimorphic (dis, twice, and wogg%, form), These plants, and many others, have thus two kinds of hermaphrodite flowers on distinct individuals. In some plants the stamens are perfected before the pistil ; these are called protandrous (aearos, first, dvjg, male or stamen), Examples of these are Ranunculus repens, Lychnis Flos-cuculi, Silene maritima, Geranium pratense and sylvaticum, Digitalis purpurea, Campanula rotundifolia, and Zea Mais. In other plants the pistil is perfected before the stamens, as in Potentilla argentea, Plantago major, lanceo- lata, and maritima, Lonicera Periclymenum, and Coix Lachryma. These are called protogynous plants (reairos, first, yuvy, female or pistil). Stamens.—The stamens (stamina) arise from the thalamus or torus within the petals, with which they alternate, forming one or more verticils or whorls which collectively constitute the andracium (dvi, male, ofx/ov, habitation), or the male organs of the plant, as distinguished from the gyneciwm (yuvj, female, ofxéov, habitation), or female organs of the plant. Their normal position is below the inner whorl or the pistil, and when they are so placed (fig. 337 e), they are hypogynous (id, under, yuv7, female or pistil). Sometimes they become united to the petals, or are epipetalous (éa/, upon, and ESSENTIAL ORGANS—STAMENS, 213 wérohov, a leaf), and the insertion of both is looked upon as similar, so that they, are still hypogynous, provided they are independent of the calyx and the pistil. In fig. 338, the stamens, ¢, and the petals, p, are below the pistil or ovary, o, and both are separate from it and from the calyx, c, and are therefore hypogynous. When the stamens are inserted on the calyx, that is, are united to it toa greater or less height above the base of the pistil, then they become lateral as it were in regard to the latter, and are perigynous (weg, around). This is shown in the flower of the almond (fig. 339), in which the petals, p, and the stamens, ¢, are united to the calyx, c, while the pistil is free. Fig. 337. Fig. 338, Fig. 339. When the union of the parts of the flower is such that the stamens are inserted on the top of the ovary, they are epigynous (éa/, upon or above). In this case the torus is supposed to be united to the ovary, while the calyx is above it, and bears the stamens. In the Orchis tribe, where the stamens and pistil are united so as to form a column, the flowers are said to be gynandrous. In Aralia spinosa (fig. 340), all the whorls, calyx, c, petals, p, and stamens, ¢, are united by the torus to the pistil, and the two latter whorls appear to rise from the point where the calyx joins the upper part of the pistil. These arrange- ments of parts have given rise to, certain divisions in classification, Fig. 337. Central part of the flower of Liriodendron tulipifera, the tulip-tree, composed of carpels, ¢ c, which together form the pistil. They cover the upper part of the axis, a, and below them are inserted numerous stamens, some of which are seen, ee. These stamens are hypogynous and extrorse. Fig. 388. Section of a flower of Geranium Robertianum. cc, Calyx. p, Petals. ¢, Stamens. Pistil composed of ovary, 0, and style and stigmata, s. t, Torus or Thalamus. The petals and stamens are hypogynous, and the latter are monadel- phous. Fig. 339. Section of the flower of the Almond-tree. The letters indicate the same parts as in the last figure. The petals and stamens are perigynous, The pistil is free. 214 ESSENTIAL ORGANS—STAMENS. to be afterwards particularly noticed. For instance, the term tha- lamifloral is applied to plants having a polypetalous corolla and all the whorls in- serted immediately into the torus or thala- mus ; calycifloral to those where the petals are separate or united, and the stamens are inserted directly on the calyx; corollijfloral to those in which the united petals are placed under the ovary, and the stamens are either borne by them, or are inserted inde- Fig. 340. pendently into the torus. The stamens vary in number, from one to many hundred. Like the other parts of the flower, they are modified leaves, resembling them in their structure, development, and arrangement. They consist of cellular and vascular tissue. They appear at first in the form of cellular projections, and are arranged in a more or less spiral form. In their general aspect they have a greater resemblance to petals than to the leaves, and there is often seen a gradual transition from petals Fig. 342. to stamens. Thus, in Nymphea alba, the White Water-lily (figs. 341, 342), ¢ represents a sepal, which gradually passes into the petals, p, and these in their turn become modified so as to form the stamens, ¢, which are more or less perfect as we proceed from without inwards, or from 1 to 5. When flowers become double by cultivation, the stamens are converted into petals, as in the Peony, Camellia, Rose, Fig. 340. Section of the flower of Aralia spinosa, Letters as in last figure. The petals and stamens are epigynous, attached to the torus, d, which covers the summit of the ovary. The ovary is adherent to the torus, and has been laid open to show its loculaments and pendulous ovules, Fig. 341, Flower of Nympheza alba, White Water-lily. cccc, The four foliola of the calyxor sepals. ppp, Petals. ¢, Stamens. s, Pistil. Fig. 342. Parts of the flower separated to show the transition from the green sepals of the calyx, c, and the white petals of the corolla, p, to the stamens, e. The latter present changes from their perfect state, 5, through intermediate forms, 4, 3, 2, and 1, which gradually re- semble the petals. ESSENTIAL ORGANS—STAMENS. 215 Anemone, and Tulip; and, in these instances, the changes from one to the other may be traced in the same way as in the Waiter-lily. When there is only one whorl, the stamens are usually equal in number to the sepals or petals, and are arranged opposite to the former, and alternate with the latter. The flower is then isostemonous (io0s, equal, and orjuwyv, a stamen). When the stamens are not equal in num- ber to the sepals or petals, the flower is anisostemonous (dévioog, unequal). When there is more than one whorl of stamens, then the parts of each successive whorl alternate with those of the whorl preceding it. The staminal row is more liable to multiplication of parts than the outer whorls. A flower with a single row of stamens is aplostemonous (daAdos, single). If the stamens are double the sepals or petals as regards number, the flower is diplostemonous (d:rAé0s, double) ; if more than double, polystemonous (woAds, many). In diplostemonous and_poly- stemonous flowers we sometimes find that the inner stamens are the younger, and thus alternate with the carpels, as in Cerastium and Lilium. In this case the development is centripetal. At other times the external are the younger, and the carpels alternate with the older stamens, as in Geranium and Heath. In this case the develop- ment is centrifugal. The outer stamens in the latter case may repre- sent interstaminal parts analogous to interpetiolar stipules. In general, when the stamens are normally developed, and are more numerous than the sepals and petals, they will be found arranged in several whorls, and their parts multiples of the floral envelopes. Thus, if a flower has five sepals, five petals, and twenty stamens, the latter are arranged in four alternate rows, having five in each. Although this is the usual law, yet various changes take place by abortion, arrest- ment of development, and other circimstances leading to abnormal growth. In this way the stamens may neither be equal to, nor a multiple of, the floral envelopes, and they may even be less numerous, so that the flower is miostemonous (we/wy, less). In Cruciferous plants, while the petals and sepals are equal in number (four), and alternate in arrangement, the stamens are six in number, four long and two short ; this imparity of numbers has been supposed to result from the splitting of the long stamens by lateral chorisis, a presumption favoured by the fact that partial union frequently exists between the two long stamens placed next each other (and superposed to the antero-posterior petals), that teeth are found only on the outer side of these long stamens, and that in many cruciferze only four stamens exist. In the case of Gloxinia, where the parts of the flower are arranged in fives, there are ouly four perfect stamens, but the fifth one is seen in the form of a small conical projection from the base of the corolla, and by cultivation the fifth stamen is sometimes fully developed, while the flowers assume a regular form, and have an erect in place of an inclined position on the peduncle. 216 ESSENTIAL ORGANS—STAMENS. In certain cases, as in Primula, the row of stamens is opposite to the petals forming the gamopetalous corolla. This opposition is by many looked upon as caused by the non-appearance of an outer row of stamens; by others it is considered as produced by chorisis or separation of laminz from the petals, which become altered so as to form stamens, a view which is thought to be confirmed by their de- velopment taking place before the petals; by a third party, each petal is looked upon when fully developed as formed by the halves of two contiguous petals, and thus the stamens are considered as being really alternate with the original petals.3 When the stamens are under twenty they are called definite, and the flower is oligandrous (dA/yos, few, and &vje, male or stamen) ; when above twenty they are indefinite or polyandrous (woAds, many), and are represented by the symbol oo. The number of stamens is indicated by the Greek numerals prefixed to the term androus; a flower with one stamen being monandrous (dvos, one) ; with two, diandrous (dis, twice) ; with three, triandrous (resis, three) ; with four, tetrandrous (rereas, four) ; with five, pentandrous (aévre, five); with six, hexan- drous (2, six); with seven, heptandrous (ard, seven); with eight, octandrous (éxr@, eight); with nine, enneandrous (ewed, nine); with ten, decandrous (dena, ten) ; with twelve, dodecandrous (dwdexc, twelve). These terms will be referred to when treating of the Linnzan system of classification. A stamen consists of two parts—a contracted portion, usually thread-like, equivalent to the petiole of the leaf, and termed the jila- ment (filum, a thread) ; and a broader portion, representing the folded blade of the leaf, termed the anther (cvdneds, belonging to a flower), which contains a powdery matter, called pollen. The filament is no more essential to the stamen than the petiole is to the leaf, or the claw to the petal. If the anther is absent, the stamen is abortive, and cannot perform its functions. The anther is developed before the filament, and when the latter is not produced the anther is sessile (sessilis, sitting), or has no stalk, as in the Mistleto. Tue FILameEnt, when structurally considered, is found to consist of a thin epidermis, on which occasionally stomata and hairs occur, and of a layer of cellular tissue enclosing a bundle of spiral vessels, which traverses its whole length, and terminates at the union between the filament and the anther. The filaments of Callitriche verna are said to have no vessels. The filament is usually, as its name imports, filiform or thread-like, cylindrical, or slightly tapering towards its summit. It is often, however, thickened, compressed, and flattened in various ways. It sometimes assumes the appearance of a petal, or becomes petaloid (wirwrov, a leaf or petal, eféoc, form), as in Canna, Maranta, Nymphzea alba (fig. 342) ; occasionally it is subulate (subula, an awl), or slightly broadened at the base, and drawn out ESSENTIAL ORGANS——-STAMENS, 217 into a point like an awl, as in Butomus umbellatus; and at other times it is clavate (clava, a club), or narrow below and broad above, like the club of Hercules, as in Thalictrum. In place of tapering, it happens, in some instances, as in Tamarix gallica (fig. 343), Peganum Harmala, and Campanula, that the base of the filament is dilated much, and ends suddenly in a narrow thread-like portion. In these cases the base may represent the sheath or vagina of the petiole, and, like it, may give off stipulary processes in a lateral direction. Sometimes the filament is forked, or divided at the apex into branches or teeth. In Allium and Alyssum calycinum there are three teeth, the central vw y(_H) one of which bears the anther. In the common garlic Fig. 349. one of the lateral teeth is somewhat cirrose. The filament varies much in length'and in firmness. The length sometimes bears a relation to that of the pistil, and to the position of the flower, whether erect or drooping. The filament is usually of suf- ficient solidity to support the anther in an erect position ; but some- times, as in Grasses, Littorella, and Plantago, it is very delicate and capillary (capillus, a hair), or hair-like, so that the anther is pendulous. The filament is usually continuous from one end to the other, but in some cases it is bent or jointed, becoming geniculate (genu, a knee) ; at other times, as in the Pellitory, it is spiral. It is frequently colourless ; but, in many instances, it exhibits different colours. In Fuchsia and Poinciana, it is red ; in Adamia and Tradescantia virginica, blue ; in (Enothera and Ranunculus acris, yellow. Hairs, scales, teeth, or processes of different kinds are sometimes developed on the filament. In Tradescantia virginica, or Spiderwort, the hairs are beauti- fully coloured, and moniliform (monile, a necklace) or necklace-like. These hairs exhibit movements of rotation (p. 153), Such a filament is bearded or stupose (stupa, tow). At the base of the filament certain glandular or scaly appendages are occasionally pro- duced, either on its internal or external sur- face. These may be either parts of a whorl, to be afterwards noticed under the name of the Disk, or separate prolongations from the filament itself. In fig. 345, a represents t Wy such a staminiferous appendage found on the rig. 344, Fig. 345. Fig. 343, Three out of ten stamens of Tamarix gallica, united together by the dilated bases of their filaments. Fig. 344, Stamen of Borago officinalis. f, Appendiculate fila- ment. a, Appendage prolonged in the form of a horn-like process. J, Lobes of the anther, Fig. 345. Stamen of Zygophyllum Fabago. jf, Filament, connected with a broad scaly appendage, a. 218 ESSENTIAL ORGANS—STAMENS. inner side of the base of the filament, f, which is hence called appen- diculate, or sometimes strumose (struma, a swelling). The processes noticed in the Boraginacee as modified petals (fig. 344 a) may be considered external appendages of the filaments, the stamen being regarded as the lamina of a petal. Filaments are usually articulated to the thalamus or torus, and the stamen falls off after fertilisation ; but in Campanula and other plants they are continuous with the torus, and the stamen remains persistent, although in a withered state. Certain changes are pro- duced in the whorl of stamens by adhesion of the filaments to a greater or less extent, while the anthers remain free ; thus, all the filaments of the andreecium may unite, forming a tube round the pistil (fig. 338 e), or a central bundle when the pistil is abortive (fig. 346, 1), the Fig. 346, 1. Fig. 346, 2. stamens becoming monadelphous (wdvos, one, and aegis, brother), as occurs in Geranium (fig. 338), Malva, Hibiscus, and Jatropha Curcas (fig. 346, 1); or they may unite so as to form two bundles, the stamens being diadelphous (é/s, twice), as in Polygala, Fumaria, and Fig. 346. Male or staminiferous flower (1), and female or pistilliferous flower (2), of Jatropha Curcas. ¢, Calyx. , Corolla. e, Stamens united by filaments occupying the centre in flower 1, in consequence of the suppression of the pistil. , Pistil in flower 2, composed of ovary, 0, with three bifid styles at its summit. a, Small glandular appendages alternating with the divisions of the corolla. Above each of the flowers is a diagram repre- senting the order in which the different parts of the flower are arranged. In diagram 1 are re- presented five parts of the calyx, five of the corolla, two rows of stamens, five in each. In diagram 2, the staminal rows are abortive, and there are three carpels forming the pistil, in the centre. Fig. 347. Triadelphous stamens of Hypericum wgyptiacum surrounding the pistil, o. ff, United filaments forming columns. ¢e, Anthers free. The outer envelope of the flower has been removed, the essential organs alone being left. . ESSENTIAL ORGANS—STAMENS. 219 Pea ; in this case the bundles may be equal or unequal. It frequently happens, especially in Papilionaceous flowers, that out of ten stamens nine are united by their filaments, while one (the posterior one) is free. When the filaments are united in three or more bundles, the stamens are triadelphous (rge7s, three), as in Hypericum egyptiacum (fig. 347), or polyadelphous (xoAds, many), as in Luhea paniculata (fig. 348, 1), or in Ricinus communis (fig. 349, 1). These staminal bundles may be sup- posed to be a compound stamen divided, or they may be looked upon as resembling digitately-divided leaves. When there are three stamens in a bundle we may conceive the bundle as representing a leaf, with two stipules united at its base. In Lauracez there are perfect stamens, each having at the base of the filament two abortive stamens or stami- nodes (fig. 357), which may be analogous to stipules. The union of the filaments takes place sometimes at the base only, as in Tamarix gallica (fig. 343); at other times it extends throughout their whole length, so Fig. 348, 1. Fig. 348, 2. Fig. 349, 2. Fig. 349, 1. that the bundles assume a columnar form. In certain cases, the co- hesion extends to near the apex, forming what Mirbel calls an andro- phore (d&vqg, male or stamen, Qogéw, I bear), or a column which divides into terminal branches, each bearing an anther (347, f ¢). Occasionally some filaments are united higher up than others, and thus a kind of compound branching is produced (fig. 349, 2). In Pancratium, the filaments are united by a membrane, which may be considered as corresponding to the crown of Narcissus. Filaments sometimes are united with the pistil, forming a columna or column, as in Stylidium, Asclepiadacex, Rafflesia, and Fig. 348, 1. Flower of Luhea paniculata. cccc, Segments of calyx. pp, Petals. ee, Stamens grouped in bundles, which alternate with the petals. s, Stigma, composed of five parts, indicating the union of five carpels. 2. One of the staminal bundles magnified, showing all the filaments united in a single mass at the base, but separating superiorly. fa, The larger internal filaments, each ending in an anther. fs, The shorter outer ones, sterile and abortive. Fig. 349, 1. Male flower of Ricinus communis, or Castor-oil plant, consisting of a calyx, c, composed of five reflexed sepals, and of stamens, ¢, united by their filaments s6 as to form many bundles, thus being polyadelphous. 2. One of the staminal bundles, f, branching above so as to leave the anthers free and separate. 220 ESSENTIAL ORGANS.—STAMENS, Orchidacee. The column is called gynostemiwm (yuvq, pistil, and orjuov, stamen), and the flowers are denominated gynandrous (yuri, pistil, dvjg, male or stamen). In the case of certain Achlamydeous (p. 192) flowers, as Euphorbia, with only one stamen developed, there is the appearance of a jointed filament bearing one anther. This, however, is not a true filament, but a peduncle with a single stamen attached to it, as proved by the fact, that in some species of Euphorbia one or more verticils are pro- duced at the joint. In this case the apparent anther represents a single flower supported on a stalk, all the parts being abortive except a solitary stamen. THE ANTHER corresponds to the blade of the leaf, and consists of lobes or cavities containing minute powdery matter, called pollen, which, when mature, is discharged by a fissure or opening of some sort. The anther-lobes may be considered as formed by the two halves of the lamina, their back corresponding to the under surface, and their face to the upper surface, united by the midrib, the pollen being cellular tissue, and the fissure of the anther taking place at the margin, which, however, is often turned towards the face. In this view, the two cavities which are found to exist in each lobe may correspond with the upper and under layer of cells, separated by a septum equivalent to the fibro-vascular layer of the leaf. Others view the anther as formed by each half of the lamina being folded upon itself, so that the outer surface of both face and back corresponds to the lower side of the leaf, and the septum dividing each cavity into two is formed by the united upper surfaces of the folded half. There is a double covering of the anther—the outer, or exothe- cium (2&w, outwards, énxiov, a covering), resembles the epidermis, and often presents stomata and projections of different kinds (fig. 350 ce) ; _ the inner, or endotheciwm (zvdov, within), is & formed by a layer or layers of fibro-cellular tissue (fig. 350 cf), the cells of which have F a spiral (fig. 23), annular (fig. 24), or reti- culated (fig. 25) fibre in their interior. This internal lining varies in thickness, Migs 300: generally becoming thinner towards the part where the anther opens, and there disappears entirely. The membrane of the cells is frequently absorbed, so that when the anther attains maturity the fibres are alone left, and these by their elasticity assist in discharging the pollen, The cells in the endothecium of Armeria maritima and Pinguicula vulgaris are reticulated, while annular cells occur in the endothecium of Cardamine pratensis. Fig. 350. Transverse section of a portion of the covering of the anther of Cobeea scandens at the period of dehiscence. ce, Exothecium, or external layer, consisting of epidermal cells. of, Endothecium, or inner layer, composed of spiral cells or inenchyma, , ESSENTIAL ORGANS—STAMENS. 221 The anther is developed before the filament, and is always sessile in the first instance. In many examples it continues permanently so. Fig. 351. Fig. 352. It appears in the form of a small cellular projection, containing a mass of mucilaginous cells (fig. 351). In the progress of growth, certain grooves and markings appear on its surface, and its interior becomes Odean tn Fig. 353. Fig. 354. hollowed out into two marked cavities, containing a mucilaginous matter (figs. 352, 353). In these cavities cells make their appearance —the outer small (figs. 852, 353, cp), forming ultimately the en- dothecium (fig. 350 cf); the interior layer forming cells in which the pollen is produced (figs. 352, 353, up). As the cavities become larger, the layer of cells (figs. 352, 353, c) between the endothecium, cp, and exothecium, ce, is gradually absorbed more or less completely, forming at first septa in the cavities; and ultimately the anther assumes its mature form, consisting of two lobes with their mem- branous coverings (fig. 354 2). In the young state there are usually four cavities produced, two for each anther-lobe, separated by the connective, and each divided by Fig. 351. Transverse section of an anther of Cucurbita Pepo, or Gourd, taken from a bud about two millimetres, or 1-12th of an English inch, in length. Fig. 352. Similar hori- zontal section from a bud in a more advanced state. ce, Outer layer of cellules (Exotheciwm) forming the epidermis. ct, Intermediate layer of cellules in several layers, most of which are ultimately absorbed. cp, Internal layer of cells (Endothectum). wp, Anther-cavities filled with large cells, which constitute the first state of the pollen-utricles, or pollinic cells. Fig. 353. Similar section -in a still more advanced state. The letters as in the last figure. Fig. 354. Anther of the Almond-tree. 1. Seen in front. [2. Seen behind. f/f, Filament attached to the connective, ¢, by a point. 12, Anther-lobes containing pollen. 222 ESSENTIAL ORGANS—STAMENS. the septum, which sometimes remains permanently complete, and thus forms a quadrilocular (quatuor, four, loculus, a pouch or box) or tetrathecal (rergcs, four, é4xy, a sac) anther. The four cavities are sometimes placed in apposition, as in Poranthera (fig. 355) and Tetratheca juncea (fig. 356), and at other times two are placed above and two below, as in Persea gratissima (fig. 357 7 7). In general, however, only two cavities remain in the anther, in consequence of the more or less complete removal of the septum, in which case the anther is said to be bilocular (bis, twice), or dithecal (d/s, twice) as seen in figs. 354, 358. Sometimes the anther has a single cavity, and be- comes unilocular (unus, one), or monothecal (u6vos, one), either by the disappearance of the partition between the two lobes, or by the abortion of one of its lobes, as in Styphelia leta (fig. 359) and Althzea, offici- nalis (fig. 360). Occasionally there are numerous cavities in the anther, as in Viscum and Rafflesia. The number of loculi or cavities is only seen when the anther opens. Fig. 356. The form of the anther-lobes varies. They are generally of a more or less oval or elliptical form (figs. 354, 361 7). Sometimes Fig. 355. Quadrilocular anther, 2, of Porauthera, attached to the filament, f, and opening at the summit by four pores, p. Fig. 356. Quadrilocular anther of Tetratheca juncea. 1, The anther entire, with its four loculaments ending in one opening. 2. Anther cut transversely, showing the four loculaments. Fig. 357. Anther of the Avocado pear (Persea gratissima), composed of four cavities or loculaments, J J, united in pairs, one above the other, and opening each bya valve, v. At the base of the filament, f, are two glands, © gg, which seem to be abortive stamens or staminodes, and which may represent stipules. Fig. 358. Pendulous anther lobes, 21, of Mercurialis annua, supported on the filament, f, and united by the connective, c. Fig. 359. Unilocular or monothecal anther of Styphelia leta, one of the Epacridacew, seen in front, 1, and behind, 2. f, Filament. 1, Anther. Fig. 360. Unilocular anther of Althea officinalis, or Marsh mallow. One of the lobes of the anther, J, abortive. jf, Filament. ESSENTIAL ORGANS—STAMENS, 223 they are globular, as in Mercurialis annua (fig. 358) ; at other times linear or clavate (fig. 362), curved (fig. 363), flexuose, sinuose, or anfractuose (anfractus, winding), as in Bryony and Gourd (fig. 364). The lobes of the anther are sometimes in contact throughout their whole length (fig. 361), at other times they are separate (figs. 358, Fig. 361. Fig. 362. Fig. 363. Fig. 364. Fig. 365. an Fig. 368. Fig. 369. Fig. 370. Fig. 371. 365). In the former case their extremities may be rounded, forming a cordate anther (fig. 354), or the apex may be acute (figs. 344, 345) ; in the latter case the lobes may divide at the base only, and end in a sagittate or arrow-like manner (fig. 366 7); or at the apex, so as to be bifurcate or forked (fig. 367 p); or quadrifurcate, doubly forked Fig. 361. Adnate or adherent anther of Begonia manicata, opening by longitudinal de- hiscence. 1, Anther-lobes. f, Filament. Fig. 362. Forked or bifurcate anther, 1, of Aca- lypha alopecuroidea, in the expanded flower. Fig. 363. Same anther in the bud, exhibiting a curved form. Fig. 364, Sinuous anther, J, of Bryonia dioica. jf, Filament. Fig. 365. Anther of Salvia officinalis. Jf, Fertile lobe full of pollen. 7s, Barren lobe without pollen. c, Distractile connective. Fig. 366. Anther of Nerium Oleander, with its lobes, 2 J, sagittate at the base, and ending at the apex in a long feathery prolongation. Fig. 367. Anther, J, of Vaccinium uliginosum, 1, Lobes ending in two pointed extremities, which open by pores. a, Appendages to the lobes. Fig. 368. Quadrifurcate anther of Gualtheria procumbens. 1, Lobes ending in four points. Fig. 369. Versatile anther of Poa compressa, /, Filament, 1, Lobes separating at each end. Fig. 370, Anther, 2, of Erica cinerea. f, Filament. 1, Lobes split partially downwards. a, Scale-like prolongations at the base. Fig. 871. Anther of Pterandra pyroidea. 1. Entire anther, seen laterally. 2. Lower half after having been cut transversely. aaa, Antherine appendages. 11, Anther-lobes. cc, Connective. 224 ESSENTIAL ORGANS—STAMENS. (fig. 368 2); or at both base and apex, so as to be forked at each extremity, as in Grasses (fig. 369). The cavities of the anther are occasionally elongated so as to end in points (fig. 368 7). Sometimes the lower part of the antherine cavities is obliterated, and they de- generate into flattened appendages (fig. 370 a). It happens at times that the surface of the anther presents excrescences in the form of warts, awl-shaped pointed bodies (fig. 367 a), or crests (fig. 371 a). That part of the anther to which the filament is attached, and which is generally towards the petals, is the back, the opposite being the face. The division between the lobes is marked on the face of the anther by a groove or furrow, and there is usually on the face a sutwre, indicating the line where the membranous coverings open to discharge the pollen. The suture is often towards one side in consequence of the valves being unequal. The anther-lobes are united either by a direct prolongation of the filament, or more generally by a body called the connective, con- sisting of a mass of cellular tissue different from that contained in the filament. In this tissue the spiral vessels of the latter terminate: From the connective a partition or septum extends across each antherine loculus, dividing it either partially or completely. The septum some- times reaches the suture. When the filament is continuous with the connective, and is prolonged so that the anther-lobes appear to be united to it throughout their whole length, and lie in apposition and on either side of it, the anther is said to be adnate or adherent (fig. 361); when the filament ends at the base of the anther, then the latter is innate or erect. In these cases the anther is to a greater or less degree fixed. When, however, the attachment is very narrow, and an articulation exists, the anthers are then movable, and easily turned by the wind. This is well seen in what are called versatile (verto, I turn) anthers, as in Tritonia, Grasses, etc. (figs. 327, 369), where the filament is attached only to the middle of the connective ; and it may occur also in cases where it is attached to the apex, as in pendulous anthers (fig. 372). ; The connective may unite the anther-lobes completely, or only partially. It is sometimes very short, and is reduced to a mere point, (fig. 358), so that the lobes are separate or free. At other times it is prolonged upwards beyond the lobes in the form of a point, as in Acalypha (fig. 363 c); or of a feathery awn, as in Nerium Oleander (fig. 366) ; or of a conical or tongue-like process (figs. 373, 374 c) ; or of a membranous expansion (fig. 375 c); or it is extended backwards and downwards, in the form of a spur, as in fig. 375 a; or downwards, as in the case of the flaky appendage in Ticorea febrifuga. In Salvia officinalis (fig. 365), the connective is attached to the filament in a horizontal manner, so as to separate the two anther-lobes, and then it is called distractile (dis, separate, traho, I draw). In Stachys, ESSENTIAL ORGANS—STAMENS. 225 the connective is expanded laterally, so as to unite the bases of the -antherine lobes, and bring them into a horizontal line. a ty Fig. 372. Fig. 373. Fig. 375. The opening of the anthers to discharge their contents is denomi- nated dehiscence (dehisco, I open). This takes place either by clefts, by hinges, or by pores. When the anther-lobes are erect, the cleft takes place lengthwise along the line of the suture, constituting longitudinal de- hiscence (figs. 354, 361, 374). At other times, the slit takes place in a horizontal manner, from the connective to the side, as in Alchemilla arvensis, and in Lemna, where the dehiscence is transverse, When the anther-lobes are rendered horizontal by the enlargement of the connective (figs. 360, 376, aq), then what is really longi- tudinal dehiscence may appear to be transverse. In other cases (fig. 376 ag), when the lobes are united at the base, the fissure in each of them may be continuous, and the two lobes may appear as one. The cleft does not always proceed the whole length of the anther- lobe at once, but often for a time it extends only partially (figs. 375, 2; 370). In other instances the opening is confined to the base or apex, each loculament (Joculus) opening by a single pore, as in Pyrola (fig. 372), Vaccinium (fig. 367), also in Solanum, where there are Fig. 376. Fig. 372. Pendulous Anther, 2, of Pyrola rotundifolia. The Anther is suspended from the summit of the filament, f, and opens at its apex by two pores, p. Fig. 873. Anther of Humiria balsamifera. 11, Anther lobes. /f, Filament, ciliated or fringed with glandular teeth. v, Conical appendage, which seems to be a prolongation of the connective. Fig. 374. Anther of Byrsonima bicorniculata. jf, Filament. 1, Anther-lobes. The empty lobes at the summit are detached in the form of two small horn-like projections. ¢, A linguiform or tongue-like appendage prolonged from the connective. Fig. 375, Sessile anther of Viola odorata, or sweet violet. 1, Seen infront. 2, Seenbehind. J, Anther-lobes. a, Spur-like appendage from the connective. c, Membranous expansion at the apex of anther-lobes. Fig. 376. Corolla of Digitalis purpurea, eut in order ‘to show the didyna- mous stamens (two long and two short) which are attached to it. ¢, Tube. f, Filaments which are united to the corolla ati, and run along its inner surface, having formed a marked adhesion. ag, Anthers of the long stamens. ag, Anthers of the short stamens. Q 226 ESSENTIAL ORGANS—STAMENS. two, and Poranthera (fig. 355), where there are four. In Tetratheca juncea the four cavities (fig. 356, 2) open into a single pore at the apex (fig. 356, 1); and in the Mistleto the anther has numerous pores for the discharge of the pollen. Another mode of dehiscence is called hanged. In the Barberry each lobe opens by a valve on the outer side of the suture, separately rolling up from base to apex ; while in some of the Laurel tribe (fig. 357 v) there are two such separating valves for each lobe, or four in all. This may be called a combination of transverse and hinged dehiscence. In some Guttiferee, as Hebra- dendron cambogioides (the Ceylon Gamboge plant), the anther opens by a lid separating from the apex, or as it is called circumscissile (circum, around, scindo, I cut) dehiscence. In the last-mentioned dehiscence the anther may be considered as formed of jointed leaves like those of the Orange, the blades of which separate at the joint. The anthers open at different periods during the process of flowering ; sometimes in the bud, but more commonly when the pistil is fully de- veloped, and the flower is expanded. They either open simultaneously or in succession. In the latter case, individual stamens may move in succession towards the pistil and discharge their contents, as in Parnassia palustris, or the outer or the inner stamens may open first, following thus a centripetal or centrifugal order. The anthers are called imtrorse (introrsum, inwardly), or antic (anticus, the fore part), when they open on the sur- face next to the centre of the flower (fig. 377); theyare eatrorse (eatrorsum, outwardly), or postice: (posticus, be- hind), when they open on the outer surface ; when they open on the sides, as in Iris, and some grasses, they are’ called laterally dehiscent (fig. 369). Sometimes ‘anthers, originally introrse, from their versatile nature become extrorse, as in the Passion-flower and Oxalis. The attachment of the filament either on the outer or inner side, and the position of the anther in the young state, assist in determining the direction of the dehiscence when the anthers open by pores, or are versatile, The usual colour of anthers is yellow, but they present a great variety in this respect. The are red in the Peach, dark purple in the Poppy and Tulip, orange in Eschscholtzia, etc. The colour and appear- ance of the anthers often change after they have discharged their functions. Sometimes a flower consists of a single stamen, as already stated in regard to Euphorbia. It is said, also, that in the Coniferz, as in Fig. 377. Tetradynamous stamens (two long and two short) of Cheiranthus Cheiri. p, Top of the peduncle. c¢, Cicatrices left by the sepals of calyx which have been removed. eg, Two pairs of long stamens. ep, The short stamens. ¢, Torus or thalamus to which the stamens are attached, ESSENTIAL ORGANS—STAMENS. 227 the Fir, and in the Cycadacez, the stamens are to be regarded as single male flowers, supported on scales; being either a single stamen with bilocular anthers, as in Pinus, or unilocular, as in Abies, or several stamens united in an androphore, as in Taxus. In the genus Pinus there are male cones composed of bract-like processes, bearing on their lower side two parallel anther-lobes, beyond which a scale-like con- nective extends. In the Yew and Cypress there is a peltate connec- tive overhanging the anthers. In Cycads there are numerous anthers on the lower surface of the scales of the male cones. Stamens occasionally become sterile by the degeneration or non- development of the anthers, which, in consequence of containing pollen, are essential for fertilisation ; such stamens receive the name of stamin- odia, or rudimentary stamens. In Scrophularia (fig. 378) the fifth stamen, s, appears in the form of a scale; and in many Pentstemons it is reduced to a filament with hairs, or a shrivelled membrane at the apex. In other cases, as in double flowers, the stamens are converted into petals ; this is also probably the case with such plants as Mesembryanthemum, where there is a multi- plication of petals in several rows. In Persea gratis- sima (fig. 357), two glands, g, are produced at the base of the filament in the form of stamens, the anthers of which are abortive ; the same thing is seen in other Lauraces. In these cases the central perfect stamen may be considered as representing the true leaf, and the two staminodes or glandular bodies, the stipules. Sometimes only one of the anther-lobes be- - comes abortive. In many unilocular anthers, the non- development of one lobe is indicated by the lateral production of a cellular mass resembling the connective. ’ In Salvias, where the connective is distractile, one of the lobes only is perfect or fertile (fig. 365, Uf), containing pollen, the other (fig. 365, Js) is imperfectly developed and sterile. In Canna, in place of one of the lobes, a petaloid appendage is produced. The stamens, in place of being free and separate, may become united by their filaments (pp. 218, 219). They may also unite by their anthers, and become syngenesious or synantherous (dv, together, yéveors, origin, &véyee, anther). This union occurs in Composite flowers, and in Lobelia, Jasione, Viola, etc. Stamens vary in length as regards the corolla. Some are en- closed within the tube of the flower, as in Cinchona, and are called included (figs. 311, 312, 376); others are exserted, or extend beyond the flower, as in Littorella, Plantago, and Exostemma. Sometimes the stamens in the early state of the flower project beyond the petals, Fig. 378. Irregular corolla of Scrophularia, with a staminodium, s, or abortive stamen, in the form of a scale. & Fig. 378. 228 ESSENTIAL ORGANS—STAMENS. and in the progress of growth become included, as in Geranium stria- tum (fig. 379). Stamens also vary in their relative lengths as respects each other. When there is more than one row or whorl in a flower, those on the out- side are sometimes longest, as in Rosaceee (fig. 339) ; at other times those in the interior are longest, as in Luhea (fig. 348, 2, fa). When the stamens are in two rows, those opposite the petals are usually shorter than those which alternate with the petals. It sometimes happens that a single stamen is longer than all the rest. In some cases there exists a definite relation, as, regards number, between the long and the short stamens. Thus, some flowers are didynamous (d/c, twice, divers, power or superiority), having only four out of five stamens developed, and the two corresponding to the upper part of the flower longer than the two lateral ones. This occurs in Labiatee and Scrophulariaces (figs. 376, 378). Again, in other cases, there are six stamens, whereof four long ones are arranged in pairs opposite to each other, and alternate with two isolated short ones (fig. 377), and give rise to tetradynamous (reredc, four, dbvapus, power or superiority) flowers, as in Cruciferze. Stamens, as regards their direction, may be erect, turned inwards, outwards, or to one side. In the last-mentioned case they are called declinate (declino, I bend to one side), as in Amaryllis, Horse-chestnut, and Fraxinella, Tur Porten.—The pollen or powdery matter contained in the anther consists of small cells developed in the interior of other cells. The cavities formed in the anther (fig. 353) are surrounded by a fibro-cellular envelope, cp, and within this are produced large cells, up, containing a granular mass (fig. 380, 1), which divides into four minute cells (fig. 380, 2), around which a membrane is developed, so that the original cell, or the parent pollen-utricle, becomes resolved by a merismatic division (p, 14) into four parts (fig. 380, 3), each of which forms a granule of pollen. The four cells continue to increase (fig. 380, 4), distending the parent cell, and ultimately causing its absorp- tion and disappearance. They then assume the form of perfect pollen- grains, and either remain united in fours, or multiples of four, as in some Acacias, Periploca greeca (fig. 381), and Inga anomala (fig. 382), or separate into individual grains (fig. 380, 5), which by degrees become mature pollen (figs. 380, 6; 383, 384). In Acacia ringens, there are eight pollen-grains united ; in Acacia decipiens, twelve ; and in Acacia linearis, sixteen. Occasionally the membrane of the parent pollen-cell is not completely absorbed, and traces of it are detected in Fig. 379. Fig. 379. Bud of polypetalous corolla of Geranium striatum, exhibiting the stamens, e ¢, at first longer than the petals, p p. ESSENTIAL ORGANS-—POLLEN. 229 a viscous matter, surrounding the pollen-grains, as in Onagracee. In Orchideous plants the pollen-grains are united into masses or pollima (fig. 387), by means of viscid matter. In Asclepiadaceze (fig. 385) the pollinia are usually united in pairs (fig. 386 0), belonging to two contiguous antherine cavities ;- each pollen-mass having a caudicular appendage, ending in a common gland, by means of which they are attached to a process of the stigma (figs. 385 p, and 386 p). The pollinia are also provided with an appendicular stami- Fig. 381. Fig. 382. : Fig. 380. Fig. 383. Fig. 384. nal covering (fig. 885 p). Pollinia in different plants vary from two to eight. Thus, there are usually two in Orchis, four in Cattleya, and eight in Lelia. The two pollinia in Orchis Morio, according to Amici, contain each about 200 secondary smaller masses. These small masses, when bruised, divide into grains which are united in fours. In Orchids each of the pollen-masses (fig. 387) has a pro- longation or stalk, called a caudicle (cauda, a tail), which adheres to a prolongation at the base of the anther, called rostellum (rostellum, a beak), by means of a viscous gland (fig. 387 g), called retinaculum (retinaculum, a band or rein). The gland is either naked or covered. Fig. 380. Development of the pollen of Viscum album, or the Mistleto. 1. Two pollen- cells or pollinie utricles filled with granular matter. 2. Four nuclei produced in this matter. 8. Separation into four masses, each corresponding to a nucleus or a new utricle. 4. Pollinic utricle containing three separate vesicles in its anterior. 5. Two of the latter, or the young pollen-grains, removed from the mother-cell or utricle. 6. The grains of pollen in their perfect state. Fig. 381. Pollen of Periploca greca, showing four grains aggluti- nated together. Fig. 382. Pollen of Inga anomala. The grains united in multiples of four. Fig. 383. Pollen-grain showing the extine covered with small punctations. Fig. 384. Pollen-grain with the extine covered with granulations. 230 ESSENTIAL ORGANS—POLLEN. The term clinandrium (xAivn, a bed, and cvjg, a stamen) is sometimes applied to the part of the column in Orchids where the stamens are « situated. Fig. 385. Fig. 386. Fig. 387. When mature, the pollen-grain is a cellular body having an exter- ‘nal covering, extine (exto, I stand out, or on the outside), and an internal, intine (intus, within). Fritzsche states that he has detected, in some cases, other two coverings, which he calls inteatine and eaintine. They occur between the extine and intine, and are probably formed Fig. 388. Fig. 389. , Fig. 390. by foldings of these membranes. In some aquatics, as Zostera marina, Zannichellia pedunculata, Naias minor, etc., only one covering exists, Fig. 385. Flower of Asclepias, showing the pollinia or pollen-masses, p, attached to the stigma, and covered by appendages. Fig. 386. Pistil of Asclepias, a, with pollen-masses, p, adhering to the stigma, s, Pollen-masses, removed from the stigma, b, united by a gland-like body. Fig. 387. Pollinia or pollen-masses of orchis, separated from the point above the stigma, with their retinacula or viscid matter attaching them at the base. The pollen- masses, p, are supported on stalks or caudicles, c, with glands at base, g. These masses are easily detached by the agency of insects. Fig. 388. Pollen-grain of Passiflora before burst- ing. 000, Opercula or lids formed by the extine, which open to allow the protrusion of the intine in the form of pollen-tubes. Fig. 389. Pollen-grain of Cucurbita Pepo, or Gourd, at the moment of its dehiscence or rupture. o 0, Opercula or lids separated from the extine by the protrusion of the pollen-tubes, ¢¢. Fig. 390. Pollen-grain of Ipomeea, with a reticu- lated extine. ESSENTIAL ORGANS—POLLEN. 231 and that is said to be the intine. The extine is a firm membrane. which defines the figure of the pollen-grain, and gives colour to it. It is either smooth, or covered with numerous projections, granules, points minute hairs, or crested reticulations (fig. 390). The colour is generally yellow, and the surface is often covered with a viscid or oily matter. The intine is uniform in different kinds of pollen, thin and transparent, and possesses great power of extension. It is said to be the first envelope formed, the other being subsequently deposited while enclosed in the parent cell. Within these coverings a granular semifluid matter called fovilla is con- tained, along with some oily particles, and occasionally starch. The fovilla contains small spherical granules, some- times the ,,3,, of an inch in diameter (fig. 391), and larger ellipsoidal or eases : elongated corpuscles (fig. 392), which Fis: 391. Hieuseay exhibit molecular movements under the microscope. Pollen-grains vary from 53, to »4, of an inch or less in diameter. Their forms are.various, The most common form of grain is ellip- soidal (figs. 392, 393), more or less narrow at the extremities, which are called its poles, in contradistinction to a line equidistant from Fig. 393. Fig. 394. either extremity, and which is its equator. In figs. 393, 394, 1 and 2, the two surfaces of the pollen-grains of Allium fistulosum and Convolvulus tricolor are represented with their poles, p, their equator, e, and the longitudinal folds in their membrane ; while at 3 are shown transverse sections at the equators, with a single fold in one case, and three folds in the other. Pollen-grains are also of a spherical, tri- angular, trigonal (fig. 396), or polyhedral figure (fig. 398). In the latter case, when there are markings on their surface, those at the Fig. 391. Pollen-grain of Amygdalus nana, the intine or internal membrane of which is protruding at three pores, under the form of as many ampulle or sacs, ¢¢t. One of these is open at the extremity, and from it is discharged the fovilla, f, composed of variously-sized granules, Fig. 392. Large granules of fovilla of Hibiscus palustris. Fig. 393. Pollen of Allium fistulosum, yp, Pole. e, Equator. 1. Pollen-grain seen on the face. 2 On the opposite side or back. 8. Transverse section through its equatorial line. Fig. 394. Pollen of Convolvulus tricolor. The letters and numbers have the same signification as in fig. 393. ' 232 FORMS OF POLLEN-GRAINS. poles, 7, sometimes differ from those at the equator, ¢. In Tradescantia virginica the pollen is cylindrical, and becomes curved ; it is polyhedral in Dipsacaceze and Composite ; nearly triangular in Proteacee and Onagracez (fig. 396). The surface of the pollen-grain is either uniform Fig. 395. Fig. 396. Fig, 397. Fig. 398. and homogeneous, or it is marked by folds dipping in towards the centre, and formed by thinnings of the membrane. In Monocotyledonous plants there is usually a single fold (fig. 393) ; in Dicotyledons, often. three (fig. 394). Two, four, six, and even twelve folds are also met with. There are also pores or rounded portions of the membrane visible in the pollen-grain. These vary in number from one to fifty. In Monocotyledons, as in Grasses, there is often only one (fig. 399) ; while in Dicotyledons, they number from Fig. 399. Fig. 400. three upwards. When numerous, the pores are either scattered irregularly (fig. 400), or in a regular order, frequently forming a circle round the equatorial surface (fig. 395). Some- times at the place where the pores exist, the outer membrane, in place of being thin and transparent, is separated in the form of a lid, thus becoming operculate (operculum, a lid), a )6as in the Passion-flower (fig. 388) and Hig. 401. Gourd (fig. 389). Grains of pollen have sometimes both folds and pores. There may be a single pore in each fold, either in the middle (fig. 401) or at the extremities; or Fig. 395, Grain of pollen of Cannabis sativa, or common Hemp. e, Equator. » p, Poles. Fig. 396. Pollen-grain of Ginothera biennis, entire, with three angles, where tubes are pro- duced. Fig. 397, The same, with one of its angles giving origin to a pollen-tube, which is formed by the intine. When the tube protrudes, the extine is ruptured. Fig. 398. Poly- hedral pollen-grain of Cichorium Intybus, or Chicory. Fig. 399. Pollen-grain of Dactylis glomerata, or Cocks-foot grass. Fig. 400. Pollen-grain of Fumaria capreolata. Fig. 401. Grain of pollen of Lythrum Salicaria, showing six folds, three of which are perforated by a pore in their middle, and three alternating with them have no pores; p 9, poles; e e, equator. 1. The grain ina diy state, 2. The grain swollen in water, so as to take a globu- lar form and display its folds, The intiae or internal membrane begins to protrude through the pores. CRYPTOGAMIC ANTHERIDIA. 233 folds with pores may alternate with others without pores ; or finally, the pores and folds may be separate. The form of the pollen-grains is much altered by the application of moisture. Thus, in fig. 401, 1, the pollen-grain of Lythrum Sali- caria, when, dry, has an ellipsoidal form, but when swollen by the application of water it assumes a globular form (fig. 401, 2). This change of form is due to endosmose, and depends on the fovilla being denser than the water. If the grains are retained in water the dis- tension becomes so great as to rupture the extine irregularly if it is homogeneous, or to cause projections and final rupture at the folds or pores when they exist. The intine, from its distensibility, is not so liable to rupture, and it is often forced through the ruptured extine, or through the pores, in the form of small sac-like projections (figs. 396, 401, 2). This effect is produced more fully by adding a little nitric acid to the water. The internal membrane ultimately gives way, and allows the granular fovilla to escape (fig. 391 f). If the fluid is applied only to one side of the pollen-grain, as when the pollen is applied to the pistil, the distension goes on more slowly, and the intine is prolonged outwards like a hernia, and forms an elongated tube called a pollen-tube (fig. 397). -This tube, at its base, is often covered by the ruptured extine, and probably also by some of the coverings mentioned by Fritzsche as intervening between it and the intine. It contains in its interior fovilla-granules, and its functions will be particularly noticed under fertilisation. The number of pollen- tubes which may be produced depends on the num- ber of pores. In some pollinia the number of tubes which are found is enormous. Thus, Amici calculates that the two pollen-masses of Orchis Morio may give out 120,000 tubes. In Cryprocamic PLants there are organs equivalent to stamens, and denominated antheridia, They consist of closed sacs of different forms, rounded, ovate, oblong, clavate, flask-like, etc., developed in different parts of the plants, con- taining a number of corpuscles immersed in a mucilaginous fluid, which at a certain period of growth are discharged through an opening at the surface. Sometimes the antheridium is a simple cell, at other times it is composed of a number of cells, as in Hypnum triquetrum (fig. 402, 1). An- theridia are sometimes confined to particular parts of the plant, at other times they are more generally diffused. Their Fig. 402. 1, Antheridium, a, of a moss called Hypnum triquetrum, at the moment when its apex is rupturing to discharge the contents, f 2, Four utricles of the contents contain- ing each a spermatozoid or moving corpuscle rolled up in a circular manner. 3, Single spermatozoid separated. Fig. 402. 234 ESSENTIAL ORGANS—THE DISK. contents are small utricles or cellules, varying, like pollen-grains, in the different orders of cryptogamic plants, and enclosing peculiar bodies called phytozoids (guriv, a plant, and Eéov, an animal), or spermatozoids (oréguc, a seed), or antherozoids (fig. 402, 2), ‘which are rolled up in a circular or spiral manner, as in Hepaticee and Mosses (fig. 402, 3). These exhibit active movements at certain periods of their existence, and resemble in this respect animalcules. In Chara vulgaris (fig. 403), the antheridium or globule, as it is called, contains cells, 1, from which proceed numerous septate (septum, a division) tubes, t. Fig. 408. In each of the divisions of these tubes, 2, there is a spermatozoid of a spiral form, which escapes, leaving the division empty, 3, and ultimately becomes unrolled, 4, exhibiting two vibratile cilia (ciliwm, an eyelash), to which its movements are referred. Tue Disx.—The term disk is applied to whatever intervenes between the stamens and the pistil, and is one of those organs to which the name of nectary was applied by old authors. It presents great varieties of form, such as a d ring, scales, glands, hairs, petaloid append- ages, etc., and in the progress of growth it often contains saccharine matter, thus * becoming truly nectariferous. The disk is frequently formed by degeneration or trans- formation of the staminal row. It may consist of processes rising from the torus, alternating with the stamens, and thus re- presenting an abortive whorl; or it may be opposite to the stamens, as in Crassula. Fig. 404. tubens (fig. 282 a). In some flowers, as Jatropha Curcas, in which the stamens are not developed, their Fig. 403. 1, Portion of antheridium or globule of Chara vulgaris. Several septate or partitioned tubes, t, attached to a utricle or vesicle, A mass of similar utricles, forming the bases of a large number of tubes, fills the cavity of the antheridium. 2, Extremity of one of these tubes, composed of several cellules, in each of which is a phytozoid or sperma- tozoid. One of the spermatozoids is represented half detached from the cellule. 3, Ex- tremity of a tube from which the spermatozoids have escaped, with the exception of the terminal cellule. 4, One of the spermatozoids separated. Fig. 404. Disk, d, of Ponia Moutan, or Tree Peony, covering the ovary, and interposed between the whorl of stamens, 3, and the pistil, p. ESSENTIAL ORGANS—THE PISTIL. 235 place is occupied by glandular bodies forming the disk (fig. 346, 2, a). In Gesneracese and Crucifere the disk consists of tooth-like scales at the base of the stamens (fig. 377, t). The parts forming the disk sometimes unite and form a glandular ring, as in the Orange ; or a dark-red lamina covering the pistil, as in Paonia Moutan (fig. 404, d); or a waxy lining of the calyx tube or hollow receptacle, as in the Rose (fig. 294, ct); or a swelling at the top of the ovary, as in Um- belliferee, in which the disk is said to be epigynous. The enlarged torus covering the ovary in Nymphea and Nelumbium may be re- garded as a form of disk. Tue Pistit.—The pistil occupies the centre or axis of the flower, and is surrounded by the stamens and floral envelopes, when these are present. It constitutes the innermost whorl, and is the female organ of the plant, which after flowering is changed into the fruit, and con- tains the seeds. It sometimes receives the name of gynaciwm (yuvn, pistil, o/xfov, habitation). It consists essentially of two parts, the ovary or germen, containing ovules or young seeds, and the stigma, a cellular secreting body, which is either seated on the ovary, and is then called sessile, as in the Tulip and Poppy *(fig. 444), or is elevated on a stalk called the style, interposed between the ovary and stigma. The style is not necessary for the perfection of the pistil. Sometimes it becomes blended with other parts, as with the filaments of the anthers in the column of Orchidaceze. Like the other organs, the pistil consists of one or more modified leaves, which in this instance are called carpels (xagmic, fruit). The analogy of carpels to leaves may be deduced from their similarity in texture and in venation; from the presence of stomata, hairs, and glands ; from their resemblance to leaves in their nascent state; from their occasional conversion into true leaves, as in Lathyrus latifolius ; and from the ovules corresponding in situation to the germs or buds found on some leaves, as those of Bryophyllum calycinum. When a pistil consists of a single carpel it is simple, a state usually de- pending on the non-development of other carpels ; when it is composed of several carpels, more or E less united, it is compound. In the first-mentioned "4% case the terms carpel and pistil are synonymous. Each carpel has its own ovary, style (when present), and stigma, and is formed by a folded leaf, the upper surface of which is turned inwards towards the axis, and the lower outwards ; while from its margins are developed one or more buds called ovules, That this is the true nature Fig. 405. Carpellary leaf of the double-flowering Cherry. In this plant the pistil is com- posed distinctly of one or more leaves folded inwards. 1, Lamina or blade of the leaf or carpel. s, Prolongation of the midrib, 1, representing the style, and ending in a circular thickened portion equivalent to the stigma. Fig. 405. 236 ESSENTIAL ORGANS—THE PISTIL. of the pistil may be seen by examining the flower of the double-flower- ing Cherry. In it no fruit is produced, and the pistil consists of sessile leaves (fig. 405), the limb of each being green and folded, with a narrow prolongation upwards, s, as if from the midrib, n, and ending in a thickened portion. When the single-flowering Cherry is examined, it is found that, in place of folded leaves, there is a single body (figs. 406, 407), the lower part of which is enlarged, forming the ovary, 0, and containing a single ovule, g, attached to its walls, with a bundle of vessels, fn, entering it, a cylindrical prolongation, ¢, forming the ) style, and a terminal expansion, s, the stigma. It will be seen that in this case two carpellary ™ leaves have become succulent, and have united together so as to form a compound pistil, with a single cavity containing one seed. The Ovary then represents the limb or lamina of the leaf, and is composed of cellular tissue with fibro-vascu- Jar bundles, and an epidermal covering. The cellular tissue, or paren- chyma, often becomes much developed, as will be seen particularly when fleshy fruits are considered. The outer epidermis corresponds to the lower side of the leaf, exhibiting stomata, and sometimes hairs ; the inner surface represents the upper side of the leaf, being usually very delicate and pale, and forming a layer called sometimes epi- thelium, which does not exhibit stomata. The vascular bundles cor- respond with the veins of the leaf, and consist of spiral, annular, and other vessels. The Style has usually a cylindrical form, consists of cellular and vascular tissue, and when carefully examined is found to be traversed by a narrow canal (fig. 407 ¢), in which there are some loose project- ing cells (figs. 408, 409), forming what is called the conducting tissue. A transverse section of the style of Crown Imperial (fig. 408) shows three vascular bundles, v v v, corresponding to three styles which are united into one, and loose cells, p, in the canal of the style. This canal is bounded by cellular tissue (fig. 409, ¢ c), traversed by spiral vessels, v v, and in its interior, besides the loose cells, » p, there are, especially at the period of fecundation, elongated tubes, f f, which in part fill up the canal. The name, conducting tissue, is given to that found in the canal of the style, on account of the part which it plays in conveying the influence of the pollen to the ovules, as will be ex- Fig. 406. Pistil or carpel of the single-flowering Cherry in its normal state. 0, Ovary. t, Style. s, Stigma. Fig. 407. The same, cut vertically, to show the central cavity of the ovary, 0, with the ovule, g, suspended from its wall,‘at a point where a bundle of nourishing vessels, fn, terminates. t, Style traversed by a canal, c, which runs from the stigma, s, to the cavity of the ovary. a / 7 Fig. 406. Fig. 407. ESSENTIAL ORGANS—THE PISTIL. 237 plained under fertilisation. Lindley has shown that in some instances the style seems to derive its origin from the placenta. The presence of the style is by no means essential to the perfection of the pistil. It Fig. 408. Fig. 409. varies in its shape and position, being usually apicilar, but from altera- tion in the direction of the central axis it occasionally seems to be lateral. Its form and appearance also vary; under ordinary cir- cumstances it is rounded in shape, ‘but occasionally becomes flattened, as in the Iris. In Clematis it is furnished with hairs ; in Euphorbia it is forked. The Stigma isa continuation of 2 the cellular tissue in the centre of the style, and it may be either ter- minal, when the canal opens at the top only (figs. 407 s, 410, 1), or lateral, when the splitting of the canal takes place on one side (fig. 411 s), or on both sides (fig. 412 ss), The stigma sometimes extends along the whole length of the style. In other instances the style is absent, and then the stigma is said to be sessile, In Orchideous plants Fig. 410. Fig. 411. Fig. 412. Fig. 408. Transverse section of the style of Fritillaria imperialis, or Crown Imperial. The style is composed of three united together. v v v, Three vascular bundles, each corresponding to one of the three styles. p, Papille or cellular bodies projecting into the cavity of the canal. Fig. 409, Structure of the canal in the centre of the style of a Campanula. cc, Cellular tissue forming its parietes traversed by trachex, v. p p, Variously formed cells, displaced as it were, and along with other elongated and filamentous ones, ff, obstructing the canal, Fig. 410. 1, Stigma, s, of Daphne Laureola, terminating the style, t. o, Summit of the ovary. 2. A small portion of the surface of the stigma, much magnified to show its papille. Fig. 411. Unilateral stigma, s, of Asimina triloba. t, Style. Fig. 412. Bilateral stigma, ss, of Plantago saxatilis. 0, Ovary. ¢, Style. 238 ESSENTIAL ORGANS—THE PISTIL. it is placed on a part of the column called the gynizus (yuvi, pistil, and iZw, I sit). It is composed of cellular tissue more or less lax, often having projecting cellules in the form of papille (fig. 410, 2), or of hairs (figs. 413, 3; 446s), and at the period of fertilisation exuding a viscous fluid, which retains the grains of pollen, and causes the protrusion of tubes. A pistil is usually formed by more than one carpel. The carpels may be arranged like leaves, either at the same or nearly the same height in a verticil (figs. 414, 415), or at different heights in a spiral cycle (fig. 337 c). When they remain separate and distinct, thus show- ing at once the composition of the pistil, as in Caltha, Ranunculus, Hellebore, and Butomus (fig, 415), the term apocarpous (amd, separate, and xaezic, fruit) is applied. Thus, in Crassula rubens (fig. 414), the pistil consists of five verticillate carpels, o, alternating with the stamens, ¢; and the same arrangement is seen in Xanthoxylon fraxineum (fig. 414). In the Tulip-tree (fig. 337) the separate car- pels, ¢ c, are numerous, and arranged in a spiral cycle upon an elongated axis or receptacle. In the Raspberry the carpels are on a conical receptacle ; in the Strawberry, on a swollen succulent one; and ‘in the Rose (fig. 294 0 0), on a hollow one, r 7, ct, which is probably a prolongation of the torus. Fig. 413. When the fruit consists of several rows of carpels on a flat receptacle, the innermost have their margins directed to the centre, Fig. 413. 1, Summit of the style, t, of Hibiscus palustris, dividing into five branches, which are each terminated by a stigma, ss, 2, One of these branches highly magnified. 8, Portion of the surface of the stigma still more magnified, to show its papille, which are elongated like hairs. Fig. 414. Pistil of Xanthoxylon fraxineum, consisting of five distinct carpels, supported on a gynophore, g. Each of the ovaries, o, bears a terminal style dilated at its extremity into a stigma, s. The five stigmata remain for a long time adherent by their sides. Fig. 415. 1, Carpels of Butomus umbellatus, consisting of folded leaves arranged. in different verticils. 2, Section of the same, showing the alternation of the parts of the flower. Three outer leaves of the perianth, o’, alternating with three inner ones, pi, three rows of stamens, co and ei, and the carpels, ce and ci. ESSENTIAL ORGANS—THE PISTIL. 239 while the margins of the outer rows are arranged on the back of the inner ones ; if the receptacle is convex, the outer carpels are lowest, as in the Strawberry; if concave, the outer ones are uppermost, as in the Rose. At other times the carpels are united, as in the Pear, Arbutus, and Chick- weed, so that the pistil becomes syn- carpous (odv, together or united), In Dictamnus Fraxinella (fig. 416) five carpels unite to form a compound pis- til. In Scilla italica (fig. 283) the three carpels form apparently only one ; but on examination it will be found that the pistil consists of three carpels alternating with thé three inner sta- mens. The union, however, is not al- ways complete; it may take place by the ovaries alone, while the styles and stigmata remain free, the pistil being then gamogastrous (ydos, union; and yaorne, ovary) ; and in this case, when the ovaries form apparently a single body, this organ receives the name of compownd ovary ; or the union may take place by the ovaries and styles, while the stigmata are disunited; or by the stigmata and the summit of the style only (fig. 414). Various intermediate states exist, such as partial union of the ovaries, as in the Rue, where they coalesce at their base; and partial union of the styles, as in Malvaceze (fig. 417). The union is usually most complete at the Fig. 418. base ; but in Labiate the styles are united throughout their length, and in Apocynaceze and Asclepiadacez the stigmata only. When the union is incomplete, the number of the parts of a com- pound pistil may be determined by the number of styles and stigmata (fig. 417 s); when complete, the external venation, the grooves on the surface, and the internal divisions of the ovary, indicate the number. When the grooves between the carpels are deep, the ovary Fig. 416. Portion of the pistil of Dictamnus Fraxinella. Two of the five varpels have been removed in order to show how the styles, s, produced on the inner side of the carpels, and at first distinct, approximate and become united into one. 0, Ovaries, two of which in front show their dorsal surface, d, and their lateral surface, 1. At the base of the gynophore, g, are seen the cicatrices, c, marking the insertion of the calyx, the petals, and the stamens. Fig. 417. Pistil of Malva Alcea. o, Nine ovaries, united so as to form one. t, Column formed by nine styles united to near their summit, where they diverge and separate. Each of the divisions of the style is terminated by a stigma, s. Fig. 418. Horizontal section of the four-celled (quadrilocular or tetrathecal) ovary of Fuchsia coccinea, cece, Wall of the ovary, which is formed by four carpellary leaves. a, Quadrangular axis to which the carpels are united. 0, Ovules attached to the inner margin of the carpels, 240 ESSENTIAL ORGANS—THE PISTIL. is denominated lobed, being one, two, three, four, or five lobed, according to circumstances. In fig. 417 the nine carpels forming the ovary, 0, are divided by grooves; and in fig, 418 a transverse section of the ovary of Fuchsia coccinea shows the four carpels which form it. The changes which take place in the pistil by adhesion, degenera- tion, and abortion, are frequently so great as to obscure its composi- tion, and to lead to anomalies in the alternation of parts. The pistil 8 more liable to changes of this kind than any other part of the ower. The carpels are usually sessile leaves, but sometimes they are petiolate, and then are elevated above the external whorls. This elevation of the pistil may in general, however, be traced to an elongation of the axis itself, in such a way that the carpels, in place of being dispersed over it, arise only from its summit. A monstrosity often occurs in the ’ Rose (fig. 419), by which the axis is prolonged, and bears the carpels, f, in the form of alternate leaves. Thus, by the union of the petioles of the carpels, or by lengthening of the axis, the pistil becomes stipitate (stipes, a trunk), or sup- ported, as in the Passion-flower, on a stalk (figs, 414, 416 9g), called a gynophore (yum, pistil, and gogéw, I bear), or thecaphore (84xn, a case). Sometimes the axis is produced beyond the ovaries, and the styles become united to it, as in Geraniaceee and Umbelliferez, In this case Fig. 419. the prolongation is called a carpophore (xaemdg, fruit, and Qogéw, I bear). The ovules are developed on the inner side of the carpel where the two edges of the carpellary leaves unite, and they are connected to it by vascular bundles which proceed from below upwards, traverse the carpel, and send a branch to each of the ovules. At the same place there is a development of cellular tissue in connection with the conducting tissue of the style and with the stigma. By the union of these tissues is fofmed the placenta, a cellular projection to which the ovules are attached. Some restrict the term placenta to the point of attachment of a single ovule, and call the union of placentas, bearing several ovules, placentaries or pistellary cords. The part of the carpel where the placenta is formed is the inner or ventral sutwre, correspond- ing to the margin of the folded carpellary leaf, while the outer or dorsal suture corresponds to the midrib of the carpellary leaf. The placenta Fig. 419. Section of monstrous Rose, as figured at page 172, the axis of which is pro- longed beyond the flower, and the envelopes removed to show the abortive stamens, r, The carpels, f, are attached alternately along the axis in the form of leaves, p, Abortive floral envelopes. s, Stamens in imperfect flower at the apex. FORMATION OF THE PLACENTA, 241 is hence sometimes called marginal. The placenta is formed on each margin of the carpel, and hence is essentially double. This is seen in cases where the margins of the carpel do not unite, but remain separate, and consequently two placentas are formed in place of one. In fig. 420 the two carpels are folded, so that their margins meet, and the placenta is apparently single ; whereas in fig. 421 the margins of each carpel do not meet, and the placenta of each is double. Again, in fig. 422, the two carpels, after meeting in the centre or axis, a, are reflected outwards towards the dorsal suture, sd, and their margins separate slightly, each being placentiferous, and bearing ovules, o. Ge te Fig. 421, Fig. 422. When the pistil is formed by one carpel, the inner margins unite in the axis, and form usually a common marginal placenta, This placenta may extend along the whole margin of the ovary as far as the base of the style, or it may be confined to the base or apex only. When the pistil is composed of several separate carpels, or, in other words, is apocarpous, there are generally separate placentas at each of their margins, In a syncarpous pistil, on the other hand, the carpels are so united that the edges of each of the contiguous ones, by their union, form a septum (septum, a fence or enclosure), or dissepiment (dissepio, I separate), and the number of these septa consequently in- dicates the number of carpels in the compound pistil. It is obvious then that each dissepiment is formed by a double wall or two lamine ; that the presence of a septum implies the presence of more than one carpel ; and that, when carpels are placed side by side, true dissepi- ments must be vertical, and not horizontal. When the dissepiments extend to the centre or axis, the ovary is divided into cavities, cells, or loculaments (loculus, a box), and it may be bilocular, trilocular, quadrilocular, quinquelocular, or multilocular, according as it is formed by two, three, four, five, or many carpels, each corresponding to a single cell or loculament (fig. 415, 2, ce, ci). In these cases the marginal placentas meet in the axis, and unite so as to form a single central one (fig. 420 a). The number of locula- ments is equal to that of the dissepiments. In fig. 418 there is shown a transverse section of the ovary of Fuchsia coccinea, ¢ ccc being its parietes formed by the union of four carpellary leaves, a the axis united to the parietes by dissepiments, and o the ovules attached Figs. 420, 421, 422, Horizontal sections of ovaries, composed of two carpellary leaves, the edges of which are folded so as to meet in the axis, a, in fig, 420; are turned inwards into the loculaments after meeting in the axis in fig. 422; and do not reach the axis in fig. 421. R 242 FORMATION OF THE PLACENTA. to the placentas at the margin of each carpel. When the carpels in a syncarpous pistil do not fold inwards completely so as to meet in the centre, but only partially, so that the dissepiments appear as projections on the walls of the ovary, then the ovary is undlocular (fig. 421), and the placentas are parietal (paries, a wall). A horizontal section of the ovary of Erythraa Centaurium (fig. 423) exhibits a unilocular ovary with parietal placentas, p, formed at the inner ‘» margins of each of the carpels, which do not meet in the centre. In these instances the placentas may Zz} be formed at the margin of the united contiguous leaves, so as to appear single, or the margins may not be united, each developing a placenta. From this it will be seen that dissepiments are opposite to placentas, formed by the union of the margins of two contiguous carpels, but alternate with those formed by the margins of the same carpel. The carpellary leaves may fold inwards very slightly, or they may be applied in a valvate manner, merely touching at their margins, the placentas then being parietal, and ‘appearing as lines or thickenings along the walls. In fig. 424 the pistil of Viola tricolor is represented, 1, cut vertically, and, 2, cut transversely, the ovules being attached Fig, 423. Fig. 424, to the walls of the ovary, and the placentas, », being merely thickened portions of the walls. Cases occur, however, in which the placentas Fig. 423. Horizontal section of the ovary of Erythrea Centaurium. c, Wall or paries of the ovary or carpellary leaf. p, The edge on which the placenta is formed, bearing the ovules, 0. 1, Cell or loculament. Fig. 424. Pistil of Viola tricolor, or Pansy. 1, Vertical section to show the ovules, v, attached to the parietes. Two rows of ovules are seen, one in front, and the other in profile. p, A thickened line on the walls forming the placenta. ce, Calyx. d, Ovary. s, Hooded stigma terminating the short style. 2, Horizontal section of the sane. p, Placenta. o, Ovules. s, Suture. Fig. 425. Pistil of Cerastium hirsutum cut vertically. 0, Unilocular or monothecal ovary. sp, Free central placenta. g, Ovules, s, Styles. -Fig. 426, The same cut horizontally, and the halves separated so as to show the interior of the cavity of the ovary o, with the free central placenta, p, covered with ovules, g. FORMATION OF THE PLACENTA. 243 are not connected with the walls of the ovary, and form what is called a free central placenta. This is seen in many of the Caryovhyllacez. Thus, in Cerastium hirsutum (figs. 425, 426), the ovary, o, is com- posed of five carpels, indicated by the styles, s, but there is only one loculament, the placenta, p, being free in the centre, and the ovules, g, attached to it. In Caryophyllacese, however, while the placenta is free in the centre, there are often traces found at the base of the ovary of the remains of septa, as if rupture had taken place ; and, in rare instances, ovules are found on the margins. But examples occur of this kind of placentation, as in Primulacee, Myrsinaces, and Santalacez, in which no vestiges of septa or marginal ovules can be perceived at any period of growth. ‘The free placenta of Primulacez is different from that of Caryophyllacez. It is always free, and rises in the centre of the ovary, and the part uncovered by ovules gradually extends into the style. It is not first continuous with the style, and then free ; neither is it originally marginal and then free; but it is, throughout its organogeny (deyavoy, organ, and yéveors, production or development), separate and axile, : Free central placentation, therefore, has been accounted for in two ways: either by supposing that the placentas in the early state were formed on the margins of carpellary leaves, and that in the progress of development these leaves separated from them, leaving the placentas _ and ovules free in the céntre ; or by supposing that the placentas are not marginal but axile formations, produced by an elongation of the axis, the ovules being lateral buds, and the carpels verticillate leaves, united together around the axis. The latter view has been supported by many botanists, and is confirmed by the fact that in some cases the placenta is actually prolonged “beyond the carpels. The first of ' these views would apply well to Caryophyl- laceze, the second to Primulacee. The latter case has been explained, on the marginal hypothesis, by considering the placentas as formed from the carpels by a process of chorisis, and united together in the centre. Some consider the axile view of placenta- tion as applicable to all cases, the axis in some cases remaining free and independent, at other times sending prolongations along the margins of the carpellary leaves, and thus forming the marginal placentas. The oc- "8 427 — Fig. 428. currence of placentas over the whole inner surface of the carpels or of Figs. 427, 428. One of the carpels of Butomus umbellatus, or flowering Rush, cut trans- versely in 427, and longitudinally in 428. 2, Loculament or cavity of the carpel. v, Ovules. s, Stigmata. 244. DIVISIONS IN OVARIES. the dissepiments, as in Nymphaea and in Butomus umbellatus (figs. 427, 428); also, though very rarely, along the dorsal suture, as in Cabomba, or on lines within the margin, as in Orobanche, has been supposed to confirm this view. Schleiden argues in favour of it, from the case of Armeria, where there are five carpels and a single ovule attached to a cord, which arises from the axis, and becomes curved at the apex, so as to suspend the ovule; also, from cases, such as Taxus, where the ovule appears to be naked and terminates a branch. This theory of placentation, however, cannot be easily applied to all cases ; and Gray says that it is disproved in cases of monstrosity, in which the anther is changed into a carpel, or where one part of the anther is thus transformed and bears ovules, while the other, as well as the filament, remain unchanged. In the case of Luffa foetida, the entangled fibres of the carpellary leaves, even in the young state, seem to be connected with perpendicular lines forming the placenta. Brongniart mentions a case where the marginal placenta was entire, while the ‘axis was prolonged separately, and totally unconnected with the placenta; he also notices peculiar monstrosities, which seem to prove that, in some cases at least, marginal placentation must take place. Upon the whole, then, it appears that marginal, or, as it is often called, carpellary placentation, generally prevails ; that axile placenta- tion explains easily cases such as Primulacez; while such instances as Caryophyllaceze are explicable on either view. Occasionally, divisions take place in ovaries which are not formed by the edges of contiguous carpels. These are called spurious ddssept- ments. They are often horizontal, and are then called phragmata (~edywa, aseparation), as in Cathartocarpus Fistula (fig. 429), where they consist of transverse cellular prolongations from the walls of the ovary, only developed after fertilisation, and therefore more pro- perly noticed under fruit. At other times they are vertical, as in Datura, where the ovary, in place of being two-celled, is rendered four-celled ; in Cruciferze, where the prolongation of the placentas forms a re- plum (replum, leaf of a door) or partition ; in Astragalus and Thespesia, where the dorsal suture is folded in- wards; in Oxytropis where the ventral suture is folded inwards; and in Diplophractum, where the inner margin of the carpels is inflexed (fig. 422). In Cucurbitacez, divisions are formed in the ovary, apparently by peculiar projections inwards from curved parietal placentas. In some cases horizontal dissepiments are supposed to be formed by the union of carpels Fig. 429. Fig. 429. Pistil of Cassia or Cathartocarpus Fistula, in an advanced state, cut longi- tudinally, to show the spurious transverse dissepiments, or phragmata. ADHESIONS BETWEEN THE TORUS AND OVARY. 245 situated at different heights, so that the base of one becomes united to the apex of another. In such cases the divisions are true dissepi- ments formed by carpellary leaves. The anomalous divisions in the ovary of the Pomegranate have been thus explained. The ovary is usually of a more or less spherical or curved form, sometimes smooth and uniform on its surface, at other times hairy Fig. 439, and grooved. The grooves, especially when deep, indicate the divisions between the carpels, and correspond to the dissepiments. Fig. 430. Flower of Cucumis Melo, or Melon. o, Inferior ovary covered by the adherent torus. Calyx, 1, and Corolla, p, being above the ovary. Fig. 431. Flower of Saxifraga Geum, cut vertically to show the ovary, 0, adherent for half its height to the torus. c, The calyx, which is called half-superior. , Petals. e, Stamens. s. Styles and stigmas. Fig. 432. Pistil of Hoteia japonica, one of the Saxifragacee, cut vertically, in order to show the interior of its two cavities or loculaments. Itis a bilocular or dithecal ovary. 0, Two ovaries consolidated into one, and adherent for half their height to the torus, ¢. t, Styles. s, Stigmas. p, Placentas covered with ovules. pe, Base of the petals. | Fig. 433. Flower of Fuchsia coccinea divided horizontally into two halves, through the middle of the ovary, o. The lower half, 2, of the ovary has been left untouched, to show its four cavities or loculi, with the ovules attached to their internal angles. (Fig. 418 shows the same section more highly magnified.) The upper half, 1, has been cut vertically, to show the ovules, g, ar- ranged in a row in each loculament. The torus incorporated with the ovary below bears the calyx, ¢ 1. p, Petals inserted on the calyx. ¢, Stamens inserted also on the tube, alternately large and small, The style rising from the summit of the ovary, and terminated by an ovoid stigma, s. 246 ESSENTIAL ORGANS—THE STYLE. The dorsal suture may be marked by a slight projection, or by a superficial groove. The ovary, as a rule, is free, in the centre of the flower, and not adherent to any of the surrounding organs. It is then termed superior, as in Lychnis, Primula, and Geranium (fig. 338). In many cases, however, it is united with surrounding parts,—most usually with the torus (receptacle), which, being prolonged into a cup-shaped expansion, becomes adherent to the ovary, and the floral whorls (calyx, corolla, stamens), proceeding from it are thus carried upwards, and rise from a plane, level with the summit of the ovary,—which is thus beneath their point of origin, and is therefore inferior, whilst they are superior. This is well seen in Rose, Almond (fig. 339), Aralia (fig. 340), Melon (fig. 430), Pomegranate, Apple, Pear, Gooseberry, and Fuchsia (fig. 433). A transverse section of the ovary of Fuchsia (figs. 418, 433) shows several closed loculaments containing ovules ; while the pistil of the Rose when cut vertically exhibits a receptacular cup or hollow torus, open at the top, and covering numerous separate carpels, arranged on its concave surface, each of the carpels consisting of ovary, style, and stigma (fig. 294, p. 196). In these examples the torus is adherent to the ovary throughout its entire extent; but in some plants, as Saxifragaceze (figs. 431, 432), the union is only par- tial, and the term half inferior is applied to the ovary, elitist the floral whorls are half superior. These appearances were formerly explained by supposing an adhesion between the calyx tube of the ovary ; and the term adherent was applied to the calyx in cases where the ovary is inferior, and the corolla and stamens were considered to be attached to and carried upwards by the adherent calyx. But this view has been superseded by the one already explained. These adhesions between the torus and the ovary will be found to be of importance, as determining the epigynous and perigynous condition of the stamens. Tur STYLE proceeds from the summit of the carpel, and may be v looked upon as a prolongation of it in an upward direction (fig. 406 ¢). It is hence called apicilar (apex, top). It consists not ¢ merely of the midrib, but of the vascular and cellular tissue of the carpel, along with a continuation of the placenta con- 4 stituting what is called conducting tissue, Fig. 434. Fig. 485. = which ends in the stigma. In some cases the carpellary leaf is folded from above downwards, in a hooded Fig. 434. Carpel of Strawberry. 0, Ovary. 1, Style arising from near the base, and pecoming basilar by the mode in which the ovary is developed ; the style, however, still indicating the organic apex of the ovury. Fig. 485. Carpel of Chrysobalanus Icaco. 0, Ovary. ¢t, Basilar style. s, Stigma. ESSENTIAL ORGANS—THE STYLE, 247 manner, so that its apex (as in reclinate vernation, fig. 222 a) ap- proaches more or less the base. When the folding is slight, the style becomes Jateral (fig. 416); when to a greater extent, the style appears to arise from near the base, as in the Strawberry (fig. 434), or from the base, as in Chrysobalanus Icaco (fig. 435), when it is called basilar. In all these cases the style still indicates the organic apex of the ovary, although it may not be the apparent apex. The carpel sometimes becomes imbedded in the torus, which consequently forms an elevated margin round it; and then, if the style is basilar or lateral, it may adhere to a portion of the torus, on one side of the carpel, and appear to arise from it. This is seen in Labiatee (fig. 436) and Boraginacez (fig. 437), where the four carpels, o, are sunk in the torus, r, in such a way that the common style, s, formed by the union of four basilar styles, seems to be actually a prolongation of the torus. When carpels are . arranged round a central pro- longation of the torus, with which their united style is con- tinuous, the arrangement is called a gynobase (yuvq, pistil, Bdors, base). It is well de- veloped in Ochnacee. In Ge- Fig. 436. raniacee there is a carpophore or prolongation of the torus in the form of a long beak, to which the styles’ are attached. The form of the style is usually cylindrical, more or less filiform and simple ; sometimes it is grooved on one side, at other times it is flat, thick, angular, compressed, and even petaloid, as in Iris and Canna. In Goodeni- aces it ends in a cup-like expansion, enclosing the stigma. It may be smooth and covered with glands and hairs. These hairs occasionally aid in the application of the pollen to the stigma, and are called collecting hatrs, as in Goldfussia ; in Campanula they appear double and re- tractile. In Aster and other Composite (fig. 438) hairs are produced on parts of the style, pc, prolonged be- yond the stigma, s; these hairs, during the upward development of Fig. 438, Fig. 436, Pistil of Lamium album, shown by a vertical section of part of the flower. Two of the four ovaries have been removed to exhibit the connection of the style with the torus, 7, by adhesion. vu, The two remaining ovaries. d, Glandular disk placed below the pistil. c, Part of calyx. p, Corolla. Fig. 487. Pistil of Eritrichium Jacquemontianum with one of the ovaries removed in front, to show the manner in which the ovaries are inserted obliquely on a pyramidal torus, r, whence the style appears to arise, ending in a stigma, s. Fig. 438. Summit of the style, ¢, of an Aster, separating into two branches, s, each terminated by an inverted cone of collecting hairs, pce. The stigma, s, is seen below as a. band or line on the inner curvature of the branches. : 248 . ESSENTIAL ORGANS—THE STIGMA. the style, come into contact with the already ripened pollen, and carry it up along with them, ready to be applied by insects to the mature stigma of other flowers. In Vicia and Lobelia the hairs frequently form a tuft below the stigma. The styles of a syncarpous pistil may be either separate or united ; when separate, they alternate with the septa. When united com- pletely, it is usual to call the style simple (fig. 433) ; when the union is partial, then the style is said to be bifid, trifid, multifid, according as it is two-cleft, three-cleft, many-cleft ; or, to speak more correctly, according to the mode and extent of the union of two, three, or many styles, The style is said to be bipartite, tripartite, or multipartite, when the union of two, three, or many styles only extends a short way above the apex of the ovary. The style of a single carpel, or of each carpel of a compound pistil, may also be divided. In fig. 346, 2, each division of the tricarpellary ovary of Jatropha Curcas has a bifurcate or forked style, s, and in fig. 439 the ovary of Emblica officinalis has three styles, each of which is divided twice in a bifurcate manner, exhibiting thus a dichotomous division. The length of the style is determined by the relation which ought to subsist be- tween the position of the stigma and that of the anthers, so as to allow the proper application of the pollen. In some cases the ovary passes insensibly into the style, as in Digitalis, in other instances there is a marked transition from one to the other. The style may remain persistent, or it may fall off after fertilisation is accomplished, and thus be deciduous, Tue Sriema is the termination of the conducting tissue of the style, and is usually in direct communication with the placenta. It may, therefore, in most instances, be considered as the placental portion of the carpel, prolonged upwards. In Armeria, and some other plants, this connection with the placenta cannot be traced. Its position may be either terminal or lateral. The latter is seen in some cases, as Asimina triloba, where it is unilateral (fig. 411), and in Plantago saxatilis (fig. 412), where it is bilateral. Occasionally, as in Tasmannia, it is prolonged along the whole inner surface of the style. In Iris it is situated on a cleft on the back of the petaloid divisions of the style. Some stigmata, as those of the Mimulus, present sensitive flattened lamine, which close when touched. The 4 Fig. 439. Fig. 439, Female flower of Emblica officinalis, one of the Euphorbiacer. c, Calyx. pp, Petals. ¢, Membranous tube surrounding the ovary. o, Ovary, crowned by three styles, s, each being twice bifurcate. ESSENTIAL ORGANS—THE STIGMA. 249 stigma consists of loose cellular tissue, and secretes a viscid matter which detains the pollen, and causes it to protrude tubes. This secreting portion is, strictly speaking, the true stigma, but the name is generally applied to all the divisions of the style on which the stigmatic apparatus is situated, as in Labiate. The stigma alternates with the dissepiments of a syncarpous pistil, or, in other words, corresponds with the back of the loculaments ; but in some cases it would appear that half the stigma of one carpel unites with half that of the contiguous carpel, and thus the stigma is opposite the dissepi- ments, that is, alternates with the loculaments. This appears to be the case in the Poppy, where the stigma of a single carpel is two-lobed, and the lobes are opposite the septa. If the stigma is viewed as essentially a prolongation of the placenta, then there is no necessary alternation between it and the placenta, both being formed by the margins of carpellary leaves, which in the one case are ovuliferous, in the other stigmatiferous. There is often a notch in one side of a stigma (as in some Rosacez), indicating apparently that it is a double organ like the placenta. To the division of a compound stigma the terms bifid, trifid, etc., are applied, accord- ing to thé number of the divisions, Thus, in Labiate (fig. 324), and in Composite (figs. 326, 438 s), the stigma is bifid; in Polemonium, trifid. When the divisions are large, they are called lobes, and when flattened like bands, lamelle ; so that stigmas may be bilobate, trilobate, bilamellar, trilamellar, ete. It has already been stated that the divisions of the stigma mark the number of carpels which are united together. Thus, in Cam- panula (fig. 440), the quinquefid or five-cleft stigma indicates ! l i Fig. 440. Fig. 441. Fig. 442. Fig, 443. Fig. 444, five carpels, the stigmata of which are separate, although the other parts are united. In Bignoniacez (fig. 441), as well'as in Scrophu- Fig. 440. Stigmas, s, of Campanula rotundifolia. 2, Style. Fig. 441, Bilamellar stigmas of-Bignonia pandorea. The two lamelle are applied naturally against each other in 1, while in 2 they are artificially separated. Fig. 442. Globular stigma of Mirabilis Jalapa. t, Style. s, Stigma. Fig, 443. Circular stigma, s, and ¢, style of Arbutus Andrachne. Fig. 444. Pistil.of Papaver somniferum, or opium Poppy. 0, Ovary. s, Radiating stigmas on its summit. * 250 PISTILLIDIA IN CRYPTOGAMIC PLANTS. lariaceze and Acanthacesx, the two-lobed or bilamellar stigma indicates a bilocular ovary. Sometimes, however, as in the case of the styles, the stigma of a single carpel may divide. It is probable that in many instances what is called bifurcation of the style is only the division of the stigma. In Graminex and Composite (figs. 331, 438) there is a bifid stigma, and only one cavity in the ovary. This, how- ever, may be probably traced to subsequent abortion in the ovary of one of the carpels. The stigma presents various forms. It may be - globular, as in Mirabilis Jalapa (figs. 410, 442); orbicular, as in Arbutus Andrachne (fig. 443) ; umbrella-like, as in Sarracenia, where, however, the proper stigmatic surface is beneath the angles of the large expansion of the apex of the style; ovoid, as in Fuchsia (fig. 433) ; hemispherical ; polyhedral; radiating, as in the Poppy (fig. 444), where the true stig- matic rays are attached to a sort of peltate or shield-like body, which may represent de- pressed or flattened styles; cucullate — 1.¢, covered by a hood, in Calabar Bean (fig. 445 a), where it is situated on the apex of a declinate style, bearded (hairy) on its concave surface (fig. 445 b). The lobes of a stigma may be flat and pointed, as in Mimulus and Bignonia (fig. 441; fleshy and blunt, smooth or granular, or they may be feathery, as in many Grasses (fig. 446). In Orchidacez the stigma is situated on the anterior surface of the column formed by the union of the styles and filaments; the point where it occurs being called gynizus (p. 238). In Asclepiadacez the stigmas are united to the face of the anthers, and along with them form a solid mass (fig. 386). In Cryprocamic Puants there exist organs called pistillidia, which have been supposed to perform the function of pistils. They are hollow flask-shaped organs, like ovaries, to which the names of sporangia (omogé, a spore or seed, and déyyoc, a vessel), and thecee (xm, a sac), have also been given. They contain bodies called spores, equivalent to ovules. These spores being capable of germination, and being devoid of cotyledons, have been termed leafless phytons. The sporangia, or spore-cases, are sometimes immersed in the substance of the plant, as in Riccia glauca (fig. 447, 1); at other times they are sup- ported on stalks, or setw (seta, a bristle), as in Mosses. In Marchantia polymorpha they consist of distinct and separate expansions, having a flask-shaped appearance (fig. 448), the lower enlarged part, 0, contain- Fig. 445. Style and stigma of the Calabar Bean (Physostigma venenoswm), showing the curved barbate style with hairs, a, on its concave surface, and a hooded (cucullate) stigma, b. ESSENTIAL ORGANS—THE OVULE. 251 ing the spores, and surrounded by a cellular coat resembling a calyx, c. From this ovary-like body there is a prolongation which may be con- Fig. 447. sidered as a style, t, terminated by a cellular enlargement, s, which has been compared to a stigma. The styloid pro- i x longation withers and disappears when the spores are mature. Sometimes the theca, as in Lichens, consist of a club-shaped elongated cell or ascus (fig. 449, 1), containing nuclei or cells in its in- terior, which form the spores. Sometimes these are single, at other times united in sets of two (fig. 449, 2), or of four (fig. 447, 2), or of some multiple of four. There are various modifications of sporangia in other Cryptogamic tribes. In Ferns, they are often surrounded by an annular ring, or by elastic bands, which cause their de- hiscence ; while in Chara they are called nucules, and present an oval form with a spiral arrangement of tubes. Tue OvuLe.—tThe ovule is the body attached to the placenta, Fig. 449. Fig. 446. Pistil of Cynodon Dactylon, a Grass. 0, Ovary. s, Feathery stigmas. Fig. 447. 1, Perpendicular section of the frond, f, of Riccia glauca, and of the sporangium or spore- case, 0, which is imbedded in it. s, Narrow process or style by which the sporangium com- municates with the external surface. 1, Its cavity or loculus. s, Young spores still united in sets of four in the parent cells, 1, Cells elongated like roots. 2, One of the cells more highly magnified, with the four spores which it contains. Three of the spores are seen, the fourth being concealed by them. Fig. 448. Sporangium or spore-case of Marchantia poly- morpha. o, Hollow swelling containing spores, and which has been compared to the ovary. t, Narrow process prolonged upwards, and resembling a style. 3s, Termination of this cellu- lar process, compared to the stigma. c, Cellular covering of the sporangium, or spore-case, surrounding it like a calyx. Fig. 449. 1, Theca or ascus of Solarina saccata, a species of Lichen, containing eight spores, united in sets of two. 2, Two of these double spores, highly magnified. 252 ESSENTIAL ORGANS—THE OVULE. and destined to become the seed. It bears the same relation to the carpel that marginal buds do to leaves, and when produced on a free central placenta, it may be considered as a bud developed on a branch formed by the elongated axis. The single ovule contained in the ovaries of Composite and Grasses may be called a terminal bud surrounded by a whorl of adhering leaves or carpels, in the axil of one of which it is produced. In Delphinium elatum ovules some- times appear as mere lobes of the carpellary leaf; in Aquilegia ovules “transformed into true leaves are occasionally produced on either margin of the carpel ; and the ovules of Mignonette sometimes assume the form of leaves. In such cases the vascular bundles of the placenta (pistillary cords) are formed by the lateral veins of the carpellary leaf. These veins pass into the marginal lobes or leaflets which represent ovules, and seem to prove that the placenta, in such cases, must be truly a carpellary, and not an axile, formation. The ovule is usually contained in an ovary, but in Conifer and Cycadaceze it is generally considered as having no proper ovarian covering, and is called naked, these orders being denominated gymno- spermous (vumvds, naked, and oxtgwa, a seed), or naked-seeded. In these orders the ovule is produced on the edges, or in the axil of altered leaves, which form no evident style or stigma, The scales of the cones in Coniferze are by some looked upon as the homologue of opened-out carpels bearing exposed ovules. In the common Fir there are usually two ovules at the base of the upper surface of each scale. In the Juniper each scale bears one ovule. In the Cypress the scales are peltate, and cover numerous ovules ; while in the Yew there is a solitary ovule at the apex of a cone-like organ formed by numerous barren scales, In Gnetacez there is also a solitary ovule, the secundine of which is pushed out into a long tube-like process. In Cycadacex the ovules are either produced on the edge of altered leaves, which some have called leaf-like carpels, as seen in Cycas, or, as in Zamia, they are covered by peltate scales, from the summit of which they are suspended. The Gymnospermal view is not , supported by all botanists ; some maintain that there is a true ovarian covering independent of the scales, and others think that the outer coat is of the nature of a disk. The subject is still under discussion. The carpellary leaves are sometimes united in such a way as to leave an opening at the apex of the pistil, so that the ovules are exposed or semi-nude, as in Mignonette. In Leontice thalictroides (blue cohosh) the ovary ruptures immediately after flowering, and the ovules are exposed. So also in species of Ophiopogon, Peliosanthes, and Stateria. In the species of Cuphea the placenta ultimately bursts through the ovary and corolla, becoming erect, and bearing the exposed ovules. The ovule is attached to the placenta either directly, when it is called sessile, or by means of a prolongation called a funiculus ESSENTIAL ORGANS—THE OVULE. 253 (funis, a cord), umbilical cord, or podosperm (wots, a foot, and orégua, a seed), This cord sometimes becomes much elongated after fertilisation. The placenta is sometimes called the trophosperm (reépu, I nourish). The part by which the ovule is attached to the placenta or cord is its base or hilum, the opposite extremity being its apea. The latter is frequently turned round in such a way as to approach the base. The ovule is sometimes imbedded in the placenta, In its simplest form, as in the Mistleto, the ovule appears as a small cellular projection. The cells multiply until they assume a more or less enlarged ovate form, constituting what has been called the nucleus (figs. 450, 451 n), or central cellular mass of the ovule. The ovular nucleus alters in the progress of growth so as to be prepared for the development of the embryo plant in its interior. At the apex of the cellular nucleus, an absorption or obliteration of cells takes place, by which a hollow cavity is formed (fig. 451 c), which in some plants becomes lined by a thin layer of cells or epithe- lium (p. 236), whilst in others the cells of the nucleus alone form its walls. This cavity is the embryo-sac, and contains amnios or mucilaginous fluid, in which, after fertilisation has been completed, the embryo plant is formed, being attached to the apex of the sac by a thread- like cellular process called the suspensor. The nucleus (fig. 457 ~) may remain naked, and alone form the ovule, as in the Mistleto, and a few other plants; but in most plants it becomes surrounded by certain coverings during its de- velopment. These appear first in the form of cellular rings at the base of the nucleus, which gradually spread over its surface. In some cases only one covering is formed, as in Composite, Campanulaces, Walnut, etc. Thus, in the latter (fig. 452), the nucleus, m, is covered by a single envelope, t, which, in the first instance, extends over the Wy LN base, and then spreads over the Fig. 452. Fig, 453. whole surface (fig. 453), leaving only an opening at the apex. In other instances (fig. 454), the nucleus, x, Fig. 450, Fig. 450. Ovule of the Mistleto entire. Fig. 451. Ovule of Mistleto cut to show the embryo-sac, ¢, and the whole of the rest of the mass, 7, composed of uniform tissue, and forming a nucleus without integuments. Fig, 452. Ovule of Juglans regia, the Walnut. t, Simple integument. 7, Nucleus, the base of which only is covered with integument at the early period of development. Fig. 453, The same ovule more advanced, in which the nucleus is nearly completely covered. i 254 ESSENTIAL ORGANS—THE OVULE. besides the single covering (fig. 454, 2, t’), has another developed sub- sequently (fig. 454, 3, te), which gradually extends over that first formed, and ultimately covers it completely, except at the opening at the apex. There are thus two integuments to the nucleus, an outer and an inner, called respectively -prinvine, te, and secundine, ti. The name tercine has been given to the cells of the nucleus which surround the embryo-sac (fig. 451). These names are applied to the coverings of the ovule without reference to théir order of development. At the apex of the ovule the primine and secundine leave an open- ing termed the foramen or micropyle (wingds, smal], and avan, a gate). This foramen extends through both coats, the opening in the primine (fig. 454, 3, ex), being the exo- stome(2&w, outside, and oréue, : . . mouth, that in the secundine (fig. 454, 3, ed), being the endostome (zvdov, within). The micro- pyle indicates the organic apex of the ovule, while the part united directly or by the funiculus to the placenta is the base or hilum. The name mi- cropyle is sometimes restricted to the foramen in the perfect seed. The length of the canal of the foramen depends on the development of the nucleus, as well as on the thickness of the integuments. The embryo- sac is sometimes prolonged beyond the apex of the nucleus, as noticed by Meyen in Phaseolus and Alsine media, and by Griffith in Santalum album and Loranthus. Some authors, as Mirbel, considering the ovule in reference to the embryo, speak of five coverings of the latter— viz. 1, primine; 2, secundine ; 3, tercine, or the covering of the nucleus lining the secundine ; 4, quartine, a temporary cellular layer, which is occasionally formed at an after period in the form of perisperm around 5, quintine, or the embryo-sac. By most botanists the nucleus and sac, with its two integuments (primine and secundine), are mentioned as the ordinary structure of the ovule. Occasionally, as in Mistleto, there are two or three embryo-sacs formed. In Veronica and Euphrasia the neck of the embryo-sac becomes elongated and swollen, and from it are developed certain cellular or filamentous appendages, which are probably connected with the nutrition of the embryo. All these parts are originally cellular. The nucleus and integu- 1 2, 3, Fig. 454. Ovule of Polygonum cymosum at various ages. mn, Nucleus. te, The outer in- tegument or primine. ti, The inner integument or secundine. ex, Exostome or opening in the primine. ed, Endostome or opening in the secundine, 1, Ovule in the early state, when the nucleus is still naked. 2, Ovule in second stage, when the nucleus is covered at its base by the internal integument or secundine only. 8, Ovule in the third stage, when the two integuments, primine and secundine, form a double covering, at the apex of which the nucleus still appears. : ESSENTIAL ORGANS—THE OVULE. 255 ments are united at the base of the ovule by a cellulo-vascular process called the chalaza (fig. 458 ch). This is often coloured, of a denser texture than the surrounding tissue, and is traversed by fibro- vascular bundles, which come from the placenta, to nourish the ovule. When the ovule is so developed that the union between the primine, secundine, and nucleus, with the chalaza, is at the hilum or base (next the placenta), and the foramen is at the opposite extremity (figs. 453, 454), the ovule is orthotropal, orthotropous, or atropous (égds, straight, and reéqmoc, mode; or u, ptivative, and rgévw, I turn). This is the position of an ovule when it first makes its appearance, and occasion- ally, as in Polygonacez, it remains as the permanent condition. In such an ovule a straight line drawn from the hilum to the foramen passes along the axis of the ovule. In general, however, changes take place in the ovule, so that it assumes a different form. Thus it may be curved upon itself, so that the foramen approaches the hilum or placenta, and ultimately is placed close to it, while the chalaza is only slightly removed from the hilum. This change depends apparently on the ovule increasing more on one side than on the other, and as it were drawing the chalaza slightly to the side of the hilum opposite to that to which the foramen is inclined. Fig. 455. Fig. 456. Such ovules are called campylotropal or campylotropous (xaarbros, curved), when the portions on either side of the line of curvation are unequal (fig. 455) ; or camptotropal (xamric, curved), when they are equal (fig. 456). Curved ovules are found in Leguminose, Cruciferze, and Caryophyllacee. The union between the parts of the curved portion usually becomes complete, but in some cases there is no union, and the ovules are licotropal, or horse-shoe shaped (Aéxos, a hollow disk, and reéqoc, mode or form), Fig. 455. Campylotropal or Campylotropus ovule of the Stock. 1, Ovule entire, 2, Ovule cut lengthwise. jf, Funiculus or umbilical cord. c, Chalaza. , Nucleus. te, Primine or outer covering. ti, Secundine or inner covering. ex, Exostome. ed, Endostome. _ Fig. 456. Carpel of Menispermum canadense, with 4 curved or camptotropal ovule, v. f, Funiculus. s, The base of the style. 256 ESSENTIAL ORGANS—THE OVULE. When, in consequence of the development on one side, the ovule is so changed that its apex or foramen (fig. 457, 4, ») is brought into close apposition with the hilum (fig. 457, 5, h), and the chalaza is also carried round so as to be at the opposite extremity (fig. 457, 5, c), then the ovule becomes inverted, anatropal or anatropous (&vargérw, I subvert). In this case (fig. 458) the union of the chalaza, ch, with the nucleus, 7, is removed from the hilum, and the connection between the chalaza and placenta is kept up by a vascular cord, r, passing through the funiculus, and called the raphe (ga, a line). The raphe often forms a ridge along one side of the ovule, and it is usually on the side of the ovule next the placenta. Some look upon this kind of ovule as formed by an elongated funiculus (fig. 457, 5, f) folded along the side of the ovule, and becoming adherent to it completely ; and support this view by the case of semi-anatropal ovules, where the funiculus is only, as it were, partially attached along one side, becoming free in the middle; and also by cases where an anatropal ovule, by the separation of the funiculus from its side, becomes an orthotropal seed. The anatropous form of ovule is of very common occurrence, and may probably aid in the process of fertilisation. Ovules which are at first orthotropous, as in Chelidonium majus (fig. 457, 2), sometimes become anatropous in the progress of development (fig. 457, 4). When the ovule is attached to the placenta, so that the hilum is in the middle, and the foramen and chalaza at opposite ends, it becomes transverse, amphitropal or heterotropal (dup, around, éregos, diverse), The position of the ovule relative to the ovary varies. When there is a single ovule, and with its axis vertical, it may be attached Fig. 457. Ovule of Chelidonium majus at different stages of development. h, Hilum or umbilicus. ch, Chalaza. jf, Funiculus or umbilical cord. 7, Raphe. », Nucleus. ti, Se- cundine. te, Primine. ed, Endostome. ex, Exostome. 1, First stage: nucleus still naked, 2, Second stage: nucleus covered at its base by the secundine. 3, Third stage: the primine developed and covering the secundine at its base. 4, Fourth stage: the ovule completely reflected, and its point turned downwards. 5, The same cut longitudinally, to show the relation of its different parts. Fig. 458, Anatropous ovule of Dandelion, cut vertically. ch, Chalaza. r, Raphe. n, Nucleus, Fig. 458. ESSENTIAL ORGANS—THE OVULE. 257 to the placenta at the base of the ovary (basal placenta), and it is then erect, as in Polygonaceze and Composite (fig. 459); or it may be inserted a little above the base, on a parietal placenta, with its apex upwards (fig. 460), and then is ascending, as in Parietaria. It may hang from an apicilar placenta at the summit of the ovary, its apex being directed downwards, and is inverted or pendulous, as in Hippuris vulgaris (461), or from a parietal placenta near the summit, and then is suspended, as in Daphne Mezereum (fig. 462), Polygalacez, and { Fig. 461. Fig. 462, Fig. 459. Euphorbiaceze. Sometimes a long funiculus arises from a basal: pla- centa, reaches the summit of the ovary, and there bending over suspends the ovule, as in Armeria; at other times the hilum or organic base appears to be in the middle, and the ovule becomes horizontal, peltate (pelta, a shield), or peritropous (aegi, around, and reérw, I turn). All these modifications are determined by the rela- tive position of the hilum and foramen, the length of the funiculus, and its adhesion, as well as the position of the placenta. When there are two ovules in the same cell, they may be either collateral, that is, placed side by side (fig. 463), or the one may be erect and the other inverted, as in some species of Spirea and Adsculus (fig. 464), or they may be placed one above another, each directed similarly. Such is also the case with ovaries containing a moderate or definite number of ovules. Thus, in the ovary of Leguminous plants (fig. 465), the ovules, 0, are attached to the extended marginal placenta, one above the other, forming usually two parallel rows corresponding to each margin of the carpel. When the. ovules are definite (uniform, and can be counted), it is usual to find their attach- Figs. 459-462. Carpels belonging to different flowers, cut vertically to show the various directions of the solitary ovule, 0, contained in them. jf, Funiculus. r, Raphe. c, Chalaza, s, Base of the style. Fig. 459. Carpel of Senecio vulgaris, with a straight or erect ana- tropous ovule. Fig. 460. Carpel of Parietaria officinalis (pellitory), with an ascending orthotropous ovule. Fig. 461. Carpel of Hippuris vulgaris (mare’s-tail), with a reversed or pendulous anatropous ovule, Fig. 462. Carpel of Daphne Mezereum, with a suspended anatropous ovule. s 258 FUNCTIONS OF FLORAL ENVELOPES. ment so constant as to afford good characters for classification. When the ovules are very numerous or indefinite, while at the same time the placenta is not much developed, their position exhibits great variation, some being directed upwards, others downwards, others transversely Fig. 463. Fig. 464. Fig. 465. Fig. 466. (fig. 466), and their form is altered by pressure into various polyhedral shapes. In such cases it frequently happens that some of the ovules are arrested in their development and become abortive. In Crypto- gamous plants, in place of ovules there are cellular bodies called spores, to which allusion will be made when the seed is considered. 4.—Functions of the Floral Envelopes. The bracts and calyx, when of a green colour, perform the same functions as leaves, giving off oxygen under the influence of light, and producing the substance called chlorophyll or phytochlor. They are consequently concerned in the assimilation of matters fitted for the nutrition of the flower, and they aid in protecting the central organs. The corolla does not in general produce chlorophyll, nor does it give off oxygen. On the contrary, it absorbs oxygen from the air. At the same time there is a conversion of starch into grape sugar, an evolution of carbonic acid gas, and in many instances a very marked elevation of temperature, caused by the combination between the carbon of the flower and the oxygen of the air. The starch, which is stored up in the receptacle and at the base of the petals, by passing into the state of dextrin and grape sugar, becomes fitted for vegetable nutrition. Important purposes are thus served in the economy of the plant. The saccharine or honey-like matter which often collects in Fig. 463. Carpel of Nuttallia cerasoides, with two suspended collateral ovules. o, One of the ovules. jf, Funiculus. s, The base of the style. Fig. 464, One of the loculaments of the ovary of Zisculus hybrida, laid open to show two ovules, 00, inserted at the same height, but turned in different directions. mm, Micropyle indicating their apex. s, Base of the style. Fig. 465. Carpel or legume of Ononis rotundifolia, with several campylotropous ovules, 0, placed one above the other. f, Funiculi. s, Base of the style. Fig. 466. Locu- lament of the ovary of Peganum Harmala, with numerous ovules, o, attached toa projecting placenta, p, and pointing in different directions. s, Base of style. FUNCTIONS OF FLORAL ENVELOPES, 259 the cup of the flower, and sometimes in special pits or depressions, as in Crown Imperial, and Asarabacca,’attracts bees and various insects, which are instrumental in disseminating the pollen. The quantity of oxygen absorbed was determined by Saussure. He found that double flowers absorbed less in proportion to their volume than single flowers ; that the essential organs absorbed more oxygen than the floral enve- lopes ; and that the greatest absorption took place when the stamens and pistil were mature. The following are the results of some of Saussure’s experiments :— Oxygen consumed— Name. I eeranene. By Flowers entire. By oe Organs Stock, single zi . 24hours. 11:5 times their vol. 18° times their vol. Do. double sy 77 ” 2! ” Polyanthes tuberosa, single ,, 9: a ” ” Do. do. double,, 7.4 ve ¥9 ” Indian Cress, single . 4, 85 59 16°3 ” Do. do. double . ,, 7°25 ” ” » Brugmansia arborea. ,, 9° ” ” ” Passiflora serratifolia . ,, 18°5 ” PP » Gourd, male flower .10,, 76 95 1 ” Do. female . ae 3°5 9 » ” Hibiscus speciosus cl Diss 54 a 63 3 Hypericum calycinum . 24 ,, 75 - 85 2s Cobza scandens . ws 6°5 - TS ae Arum italicum . eas = 3 30° % Typha latifolia. By 9°8 Fe ” ” Whitelily. . . 4, 5 i 3 He Castanea vulgaris itis 91 % ” ” While this oxidation is going on, carbon is given off in the form of carbonic acid, and heat is evolved by the combination between the oxygen and carbon. The quantity of carbonic acid evolved is in a ratio corresponding to the amount of oxygen absorbed, and the degree of heat present is proportionate to the activity of the chemical and vital changes taking place. Experiments have been made as to the amount of heat produced during flowering, especially by species of Arum, Caladium, and Colocasia. These are plants in which the floral envelopes are nearly absent, while the torus and growing point, and the essential organs, attain a high degree of development, forming a spadix enclosed in a large spathe. No heat eould be detected when the con- tact of oxygen was prevented, either by putting the plants into other gases, or by covering the surface of the spadix with oil. The surface of the spadix is tha part whence the heat is chiefly evolved. Aram cordifolium occasionally had a temperature 20° or 30° above that of the surrounding air; Arum maculatum 17° to 20°; and Arum Dra- cunculus and other species still higher. The following observations were made by Brongniart on the spadix of Colocasia odora, The spathe 260 FUNCTIONS OF FLORAL ENVELOPES. opened on the 14th of March ; the discharge of pollen commenced on the 16th, and continued till the 18th, The maximum temperature occurred at a different hour on each day. . qT rature i qT ture Maximum, sbaze the Air. Maximum. above the rs 14th March. 3 PM. 4°5° Cent. | 17th March. 5 P.M. 11°0° Cent. 15th ,, 4,, 100° ,, | 18th ,, llam. 82 ,, 16th |, 5, 10-2? ,, | 19th ,, 10-45 25°, Vrolik and De Vriese made a series of observations on the same plant, and have given the results for every half-hour of the day. The following are some of these results :— mm, sa: aie TNS aa: DRY Megane 11-30 20°6° Cent. 183° Cent. | 3 25°0° Cent. —-15°6° Cent. 12 21, 187, 3-30 24-4 ,, 150 4, 12-30-9383, 1944, 4 23-3, 150 4, ii 244 19-4, 5 22-2, 18-7 45 1-30 24-4, 189 ,, 6 21:0 ,, 18-7 ,, 2 25-6 4, 17-2, 7 20:0, 18°74 2-30 265 ,, 156, The greatest amount of heat observed was at 2-30 P.m., when it was 10°9° above the temperature of the air. On the previous day the maximum occurred at 3 p.m., and on the following day at 1, but then it was only 8°2° above that of the air. Decandolle states that at Mont- pellier, Arum italicum attained the maximum of temperature about 5 p.m. Saussure observed similar phenomena, but to a less extent, in the Gourd, where the temperature varied from 1°8° to 3°6°; also in Bignonia radicans, from 0°9° to 3°. From all these experiments it would appear that in the Aracez and some other plants, especially at the period when the essential organs reach maturity, there is a pro- duction of heat, which increases during the performance of their functions, attaining a daily maximum, and ultimately declining. While these changes are taking place the starch is converted into dextrin, and ultimately into grape-sugar, which, being soluble, can be immediately applied to the purposes of the plant. Flowering takes place usually at a definite period of the plant’s existence. The process requires a considerable amount of nutrient matter, and its occurrence is accompanied by a greater or less ex- haustion of the assimilated products. A certain degree of accumulation of sap seems necessary in order that flowering may proceed. Annual plants are so exhausted after flowering as to die; but, by retarding the epoch for two or more years, as by nipping off the flower-buds, time is allowed for accumulating sap, the stems, from being herbaceous, become shrubby, and sometimes, as in the Tree-Mignonette, they may live and flower for several years, Perennial plants, by the retardation PERIODS OF FLOWERING. 261 of flowering, are enabled to accumulate a greater amount of nutritive matter, and thus to withstand the exhaustion. Many cultivated plants which lay up a large store of nutriment in the form of starch, lose it when the plants shoot out a flowering stem. This is seen in the case of Carrots and Turnips, in which the succulent roots become fibrous and unfit for food when the plants are allowed to run to seed. The receptacle of the Artichoke and many Composite, which is succu- lent before the expansion of the flowers, becomes dry as the process of flowering proceeds. The juices of plants, when required for the pur- pose either of food or medicine, ought in general to be collected immediately before the flowering of the plant. By cutting a ring out of the bark of trees, and thus retarding the descent of the sap, the period of flowering is sometimes hastened. Again, when the period of flowering is long delayed, either naturally, as in Agave and several palms, or artificially, the process, when it does begin, proceeds with amazing rapidity and vigour. Richard mentions that a plant of Agave, which had not flowered for nearly a century, sent out a flowering stem of 224 feet in 87 days, increasing at one period at the rate of one foot a day. In such cases this vigor- ous flowering is often followed by the death of thé plant. Common fruit trees, when they begin to flower, often do so luxuriantly ; but if, from the season being bad, there is a deficiency in flowering, it frequently happens that, from the accumulation of nourishment, the next year’s produce is abundant. If plants are allowed to send' out their roots very extensively in highly nutritive soil, the tendency is to produce branches and leaves rather than flowers. In such cases, cutting the roots or pruning the young twigs may act beneficially in checking the vegetative functions. In pruning, the young shoot is removed, and the buds connected with the branch of the previous year are left, which thus receive accumu- lated nourishment. Grafting, by giving an increase of assimilated matter to the scion or graft (see remarks on Fruiting), and at the same time checking luxuriant branching, contributes to the hastening of the period of flowering. The period of flowering of the same plant varies at different seasons, and in different countries. During the winter, in temperate climates, and during the dry season in the tropics, the vegetative pro- cess is checked, more especially by the diminished supply of moisture,, and the arrestment of the circulation of the sap. The assimilated matter remains in a state of repose, ready to be applied to the purposes of the plant when the moisture and heat again stimulate the vege- table functions. This stimulation occurs at different periods of the year, according to the nature of the climate, By observing the mode of flowering of the same species of plant in successive years, conclusions may be drawn as to the nature of the seasons in a 262 PERIODS OF FLOWERING. country ; and by contrasting these periods in different countries, comparisons may be instituted as to the nature of their climate. Thus valuable floral calendars may be constructed. Plants are accommodated to the climate in which they grow, and flower at certain seasons, and even when transferred to other climates where the seasons are reversed, they still have a tendency to flower at their accustomed period of the year. Again,'in the same climate, some individuals of a species, from a peculiar idiosyncrasy, regularly flower earlier than others. Decandolle mentions a horse-chestnut at Geneva, which flowered always a month before the rest in the neigh- bourhood. From such individuals, by propagation, gardeners are able to produce early-flowering varieties. There is a periodicity as to the hours of the day at which some species open their flowers. Some expand early, some at mid-day, others in the evening. The flowers of Succory open at 8 a.m., and close at 4 p.mM.; those of Tragopogon porrifolius, or Salsafy, close about mid-day. lLinnzus constructed a floral clock or watch, in which the different hours were marked by the expansion of certain flowers. The periods, however, do not seem to be always so regular as he remarked them at Upsal. The following are a few of these horological flowers, with their hours of opening :— Ipomea Nil 3to 44.mM Tragopogon pratense 4to 5 ,, Papaver nudicaule 5 *3 Hypocheris maculata . 6 re Various species of Sonchus and Hieracium 6to 7 ,, Lactuca sativa 7 59 Specularia Speculum Tto 8 Calendula pluvialis ° ” Anagallis arvensis 8 33 Nolana prostrata . 8to 9 ,, Calendula arvensis ‘ = 9 se Arenaria rubra. s : ‘ . 9told ,, Mesembryanthemum nodifloram x 3 » JO w ALL 4; Ornithogalum umbellatum (Dame d’onze “heures) _ ill 5a Various Ficoideous plants. 2 : : . 12 5 Scilla pomeridiana 4 ‘ - 3 2 P.M. Silene noctiflora . ‘ , S . ‘ ~ FTE DB og Cnothera biennis 2 r . 6 a Mirabilis Jalapa . ‘ j . é . 6to 7 ,, Cereus grandiflorus : 7to 8 ,, Plants which expand their flowers in the evening, as some species of Hesperis, Pelargonium, etc., were called by Linnseus plante tristes on that account. Several species of Cooperia, and of Cereus, also Sceptranthus Drummondii, are nocturnal flowers. Some flowers open and decay in a day, and are called ephemeral, others continue to open and close for several days before withering. The corolla usually PERIODS OF FLOWERING. 263 begins to fade after fecundation has been effected. Many flowers, or heads of flowers, do not open during cloudy or rainy weather, and have been called. meteoric, Composite plants frequently exhibit this phenomenon, and it has been remarked in Anagallis arvensis, which has hence been denominated the “poor man’s weather-glass.” The closing of many flowers in such circumstances protects the pollen from the injurious effects of moisture. The opening and closing of flowers is regulated by light and moisture, and also by a certain law of periodicity. A plant accustomed to flower in daylight at a certain time, will continue to expand its flowers at the wonted period, even when kept inadark room. Decan- dolle made a series of experiments on the flowering of plants kept in darkness, and in a cellar lighted by lamps. He found that the law of periodicity continued to operate for a considerable time, and that in artificial light some flowers opened, while others, such as species of Convolvulus, still followed the clock hours in their opening and closing. Light has been said also to have an effect on the position which flowers assume. Some Composite as Hypocheris radicata and Apargia autumnalis, are stated by Henslow to have been seen in meadows, where they abound, inclining their flowers towards the quarter of the heavens in which the sun is shining. A similar state- ment has been made regarding the Sunflower, but it has not been confirmed in this country at least. Perhaps in its native clime, where the effect, of the sun’s rays is greater, the phenomenon alluded to may be observable. The effects of light on the direction of the flowers has been noticed in many plants, as Narcissus and certain species of Melampyrum. It is of importance, both as regards meteorology and botanical geography, that observations should be made carefully on what are called the annual and diurnal periods of plants: the former being the space of time computed between two successive returns of the leaves, the flowers, and the fruit ; and the latter, the return of the hour of the day at which the flowers of certain species open. The same species should be selected in different localities, and care should be taken that the plants are such as have determinate periods of flower- ing. Rules as to the mode of observing periodical phenomena in plants have been drawn up by a committee of the British Association, and they have published (1.) a list of plants to be observed for the periods of foliation and defoliation ; (2.) a list of plants to be noticed for flowering and ripening of the fruit; (3.) a list of plants to be observed at the vernal and autumnal equinoxes, and summer solstice, for the hours of opening and closing their flowers, 264 FERTILISATION OR FECUNDATION. 5.—Functions of the Organs of Reproduction—Fertilisation or Fecundation. The stamens and pistil are called the Essential Organs of flowering plants, inasmuch as without them reproduction cannot be effected. In plants which do not flower, this function is performed either by special organs, which have been termed antheridia and archegonia, or it is accomplished by a process of conjugation or union of cells. The stamens, considered as the male organs, prepare the pollen, which is discharged by the dehiscence of the anther. The pistil, or the female organ, is pro- vided with a secreting surface or stigma, to which the pollen is applied in order that the ovules contained in the ovary may be fertilised. The existence of separate sexes in plants appears to have been conjectured in early times, as shown by the means taken for perfecting the fruit of the Date Palm. In this palm, the stamens and pistils are on separate plants; and the Egyptians were in the habit of applying the sterile flowers to those in which the rudiments of the fruit appeared, in order that perfect dates might be produced. This practice appears to have been empirical, and not founded on correct notions as to the parts of the plant concerned in the process. In the case of the Fig, they were in the habit of bringing wild figs in contact with the cultivated ones, on the erroneous supposition that a similar result was produced as in the case of the Date, proving that they were not aware of the fact that in the Fig there are stamens and pistils present on the same receptacle. The effect produced by the wild figs, or the process of caprification (caprificus, a wild fig-tree), as it was called, seems to depend on the presence of a species of Cynips, which punctures the fruit, and causes an acceleration in ripening. The presence of sexual organs in plants was first shown in 1676, by Sir Thomas Millington, Savilian Professor at Oxford, and by Grew. The opinions of these naturalists were subsequently confirmed by Malpighi, Ray, Morland, Geoffrey, and others. Linnzeus made these organs the basis of his artificial system of classification. Numerous proofs have been given of the functions of the stamens and pistils, especially in the case of plants where these organs are in separate flowers, either on the same or on different plants. Thus, a pistilliferous specimen of Palm (Chamerops humilis), in the Leyden Botanic Garden, which had long been unproductive, was made to pro- duce fruit by shaking over it the pollen from a staminiferous specimen. The same experiment has on several occasions been performed in the Botanic Garden at Edinburgh, and the fruit thus ripened has furnished seeds which have germinated. Similar results were observed in the case of the Pitcher plant. In Cucumbers, when the staminiferous flowers are removed, no perfect fruit is formed. Removing the FERTILISATION OR FECUNDATION. 265 stamens in the very early state of the flower, before the pollen is perfectly formed, prevents fertilisation. Care must be taken, in all such experiments, that pollen is not.wafted by the wind or carried by insects to the pistil from other plants in the neighbourhood, and the result must be put to the test by the germination of the seed. In some instances the fruit enlarges independently of the application of the pollen, without, however, containing perfect seed. Thus, a species of Carica was fertilised by the application of pollen, and produced perfect fruit and seed, and it continued for at least one year afterwards to have large and apparently perfect fruit, but the ovules were abortive. Some authors maintain that in the case of Hemp, Spinach, Lychnis dioica, Coelebogyne ilicifolia, Aberia Caffra, and some other plants, perféct seeds have been produced without the influence of pollen, but these statements have not been confirmed. Such cases are recorded as examples of Parthenogenesis (wagdévos, maiden, yéveors, origin), or the production of perfect seeds without fertilisation. In Phanerogamous or flowering plants all experiments lead to the con- clusion that there are distinct sexual organs, the presence of which is required for the production of the embryo. In Cryptogamous or flowerless plants there are also organs of re- production, although they are not always very conspicuous. In the simplest form of Cryptogamic plants, reproduction and nutrition progress within the same cell. As we ascend in the scale of vegeta- tion, and the plant becomes more complex, there are cells of different kinds, which require to be brought into contact in order that spores (which are equivalent to seeds) may be produced. These reproductive cells are of two kinds, and they are situated either together or apart, on the same or on different individuals, one Fig. 467. Fig. 468." representing the male and the other the female. §& One of these is the Antheridiwm (avdngic, flowery, ¢/d0¢, form), a cellular body, containing free cells, in which are enclosed Phytozoa (purty, a plant, and Zw, living), (Antherozoids), minute bodies which exhibit movements ; the other is the Pistillidiwm or Archegonium (dex7, begin- ning, and yévos, offspring), containing cells which, after contact with phytozoa, are able to germinate, and which are sometimes provided Fig. 469. Fig. 470. with cilia (figs. 467-470), and then are called Zoospores (Cwos, living, and omogé, a seed or spore), or moving spores. The phytozoa are re- garded as exercising a function similar to that of the spermatozoa in animals, and hence they are sometimes called Spermatozoids (onéguc., Figs. 407-470. Spores of different fresh-water Alge. Fig. 467. Sporesof Conferva, with two vibratile cilia. Fig. 468. Spore of Chetophora, with four cilia. Fig. 469. Spore of Prolifera, with a circle of cilia. Fig. 470, Spore of Vaucheria, covered with cilia, 266 ’ CRYPTOGAMIC EMBRYOGENY. seed). A cessation of their active movements has been observed co- incident with the earliest formation of the embryo. When the contents of the antheridia and archegonia are brought into contact, a cellular body is produced in the latter. This cell or germ, when mature, may either be discharged, or may remain in connection with the plant until further developed. Fertilisation or Fecundation in Cryptogamous or Flowerless Plants, In the simplest Cryptogamic plants, composed of a single rounded cell, as the Yeast plant, the Red-snow plant, and Palmella cruenta (fig. 44, p. 14), the processes of reproduction and ve nutrition cannot be separated. The same cell ap- : pears to perform both functions, At a certain period of growth divisions take place in the cell- contents, and by the bursting of the parent cell germs are discharged which are capable of produc- ing new individuals. As we ascend in the scale the plants become more complex. In place of one cell q they consist of several, united together either in a “ single or branched linear series, and combined both end to end and laterally, so as to form cellular ex- pansions. In this state the nutritive and reproduc- tive cells are often separate and distinct, as may be seen in common Mould, and in Fungi generally. In Conferve (fig. 45, p. 14), and in Diatomacese (fig. 472), reproductive cells are observed with distinct functions. In many of them we perceive at certain Fig. 471. stages of growth cells uniting by a process of conju- gation, the result of this union being the pro- duction of a cellular embryo or spore. This conjugation is a very interesting process, and tends to throw light on the subject of reproduction throughout the whole vegetable kingdom. It is well seen in species of Zygnema, Spirogyra, Tyndaridea, Mougeotia, and Staurospermum, which are called Conjugate on this account. The cells in these plants have in their interior a granular endochrome, which appears to have different functions in the different cells. When certain cells are brought into contact, tubes are emitted which unite the two (fig. 471 6), the endochromes come into contact and the result is the formation of a spore, the mixed endochromes being surrounded with a proper membrane. Sometimes the contents of Fig. 471. Filaments of Zyguema, with conjugating cells. The tubes uniting two cells are seen at b, and similar tubes connect two upper cells, a and d. The contents of the cells intermingle, and spores or sporoid embryos, c and d, are produced. The upper cells, in which there is no conjugation, retain their usual contents; while some of the lower cells have lost their contents, and spores are produced in others. ai” 6 5 EMBRYOGENY IN CELLULAR PLANTS. 267 one cell, considered as the male, pass into the other in which the spore is produced, as in Zygnema (fig. 471), and sometimes the contents of both cells unite, and the spore is produced in the tube between them. Besides this process of conju- gation, by means of which a cellular embryo is formed, some of these plants have a power of merismatic or fissi- parous division (fig. 472), by which He cells are separated, capable of inde- pendent existence. This may be compared to the process of budding, and is thus distinct from fecundation. In many of the Confervee, however, spores appear to be produced without the conjugation of separate filaments. In such instances it is conjectured that different cells in the same filament perform different functions, and are so placed that at a certain period their contents by coming into contact develop a fertile germ. The same filament may thus contain both. male and female cells; although botanists as yet have not been able to show the difference between them. In some species of Meloseira the endochrome at each end of the cell appears to have a different property, and mixture takes place in the cavity of a single frustule. In this case there is a movement towards the centre of the cell where the spore is formed. Proceeding to other divisions of Acotyledons, we find different kinds of reproductive organs, which can, however, only be observed at certain periods of development, and frequently cannot be seen after the embryo has been fully formed. In the same way as in flowering plants, when the seed has been ripened the stamens have generally withered and fallen off, and sometimes also the style and stigma. It is of importance, therefore, in all investigations into Cryptogamic reproduction, to examine the plants at an early period of their growth. The reproductive organs have received different names in the several orders of Cryptogams. The usual name applied to the male organs is antheridia, containing sperm-cells with phytozoa; and to the female organs, archegonia, containing germ-cells. We shall now proceed to examine the reproductive organs and their functions in various divisions of flowerless or Cryptogamous plants. In the case of Fungi (the mushroom order), reproductive bodies called spores are produced, either naked (often stalked) or contained in sacs called thecw (64x, a box) or asci (ascus, a bag). Many of the spores, such as those called conidia (xéms, dust), are rather of the nature of buds. In some fungi, as Peronospora, a conjugation of cells has been Fig. 472. Diatomaceous Alga (Diatoma marinwm), the cells of which are increased by a constant process of fissiparous or merismatic division. The plant increases by abscission of segments. \ 268 EMBRYOGENY IN FUNGI. observed, and in Zyzygites megalocarpus as well as in species of Rhizopus (R. nigricans), the formation of a compound spore by the complete amalgamation of two cells has occasionally been noticed. This compound spore is termed a zygospore (Cuyiv, a yoke). The bodies called cystidia (xdoric, a bladder), seen in Fungi, are supposed to represent antheridia ; while others called oogonia (div, an egg, and Fig. 473. yéws, offspring), are reckoned as equivalent to archegonia or sporangia, in which, after the action of the antheridia, a fertilised spore is formed, which is denominated an oospore, In Lichens, which are Thallogens, reproductive bodies called spores a : Ne Ol 6k, eats Wa" tan ‘gitar ee ” Fig. 475. Fig. 476. Fig. 477. ® occur in thece or asci, which are united in the form of open discs or apothecia (dab, from, 64x, box), and in hollow conceptacles called perithecia (wegi, around). On the thallus of lichens smaller hollow sacs, called spermagones (oréguc, seed, vyévos, offspring), also occur (fig. 473). These when cut through show bodies inside called spermatia (fig. 474), which some consider as representing antherozoa or sperma- tozoids ; they are supported on stalks called sterigmata (orjerypa, a Fig. 478. Two Spermagones on thalli of Lichens. Fig. 474, Spermagones of a Lichen cut through, showing outer filaments, f (hypha), with rounded green cells, g (gonidia) ; in the interior sterigmata and spermatia; opening at top, o. Fig. 475. Sterigmata, a, and sper- tmatia, b, of Cladonia fimbriata. Fig. 476. Pycnides of a parasitic Lecidia on thallus of a Cladonia. Fig, 477. Basidia, a; stylospores, 0; free stylospores, c, from pycnides of same Lecidia. EMBRYOGENY IN LICHENS. 269 support), (fig. 475). Besides the spermagones, other externally similar reproductive bodies, called pycnides (vavis, crowded) (fig. 476), are, though less regularly, produced on the thallus, containing minute bodies denominated stylospores (fig. 477 b), which are either attached to style-like stalks (basidia), a, or are found free, c. The fertilisation of Lichens is still very obscure, and the functions of their several reproductive organs require further examination. In the thallus of lichens there are interlaced filaments or threads, forming what is called the hypha (fig. 474 f), (bo7, weaving), in the midst of which are peculiar green-coloured rounded bodies, called gonidia. (fig. 474 g) (yévos, offspring, ¢7é0s, form), which appear to be concerned in vegetative propagation, like the zoospores of Algs. These gonidia have been shown in some cases, as in Parmelia parietina, to contain corpuscles capable of development into zoospores, In the division of Thallogens called Algee, embracing Cryptogams, which inhabit salt and fresh water, there are more evident organs of fecundation. We have already noticed these in the case of the conjugation of confervee (fig. 471), when two cells being different, the: contents unite to form a spore or germinating body. This process is seen also in Diatoms and Desmidiee. In the minute Closterium Lunula there is a fissiparous division of the plant, and the contents of the two ruptured cells unite to form a rounded body, containing a spore. Besides the process of conjugation, there are also other modes of reproduction in Alge; the same plant is seen forming cells which separate as independent plants, and also antheridia and archegonia which give rise to spores. In Vaucheria there is a multiplication by zoospores or moving cells, which are discharged from the extremity of a fila- ment (fig. 478 a and b). This zoospore (fig. 478 b) is a vegetative reproductive body, independent of fertilisation. The plant also produces a recurved horn-like organ, which performs the part of an an- theridium, and a slightly recurved organ close beside it, which represents the sporangium, from which a beak-like process is turned in the direction of the antheridium. These two organs are then in direct communication by their bases with the tube of the Vaucheria, but they are afterwards separated from it, each forming a septum. Spermatozoids, contained in the an- theridium, afterwards penetrate the beak-like process of the spo- a. Fig. 478 0. Fig. 478 a. Clavate cellular filament of an Alga(Vaucheria ovoidea). The terminal portion becomes separated from the rest by a partition. In this portion the single spore, s, is de- veloped, which is discharged through an opening, as seen in the figure. The spore has cilia, by means of which it moves about for some time in water after being separated from the parent cell, The lower part of the filament contains green endochrome. The spore is of a very dark green colour. b, Zoospore of an Alga (Vaucheria), surrounded by moving cilia, 270 EMBRYOGENY IN ALGA, rangium, and thus fertilisation is effected, and the true spore is formed in the interior. In Vaucheria there are thus three reproductive organs :— 1. Zoospores, which are vegetative or bud-like reproductive organs (moving spores). 2. Antheridia, with sperm-cells containing fusiform corpuscles, which move by means of two cilia. 3. Sporangia, with germ-cells, which are fertilised by the intel corpuscles. and form resting spores, whence the new plants arise. Pringsheim has examined the reproduction in two minute Algw, Cdogonium and Bulbochete. The greater part of the cells of Gido- gonium contain each a zoospore (fig. 479, 1, a), provided anteriorly with a complete crown of cilia. This body (zoospore) is produced without sexual intercourse; it germinates and gives rise to a new plant in the same way as a bud does. Between the common cells of the cellular plants occur other utricles, usually more swollen, (fig. 479, 1, 2, 66), either isolated or in groups. In these are formed motionless spores (or resting spores), which are the female sexual organs. In the individuals which produce these female cells, as well as in others which have no such cells, there occurs a third’ kind of cell, shorter than the common cell of the plant, and forming often irregular groups. The third kind gives birth to spermatozoids, either at once or after the appearance of an intermediate production of a special nature, which becomes detached from the primordial filament, and contains the male sexual apparatus. In Cidogonium ciliatum, a small species, found attached to the leaves of aquatic mosses, the cells containing the male organs are formed towards the anterior extremity of the filament, between the setiform terminal cells (fig. 479, 1, 2, d) and the upper female organ. In each of these cellules there is formed, at the expense of the contained plastic materials, a single small zoospore called microgonidium (wimeds, small). This, according to Pringsheim, is the antecedent or generator of the male organs. These male organs have been called androspores (dye, male). These andro- spores, furnished with a circle of cilia at their anterior and transparent part, after quitting their mother-cells, move about at first, and then become fixed (in a determinate manner in each species) either to the female organ itself or in its neighbourhood. Pringsheim has seen in Cidogonium ciliatum several androspores fix themselves on the surface of the female organ (fig. 479,1,2,ccc), The latter organ continues to be developed, while each androspore becomes a sort of compound cellular plant. In one part of this the spermatozoids are formed, and hence it is called the antheridium. The fixed androspore acts like a mother-cell. The antheridium, properly so called, represents the secondary utricle produced at the upper part of the androspore, and the stalk of the antheridium is formed by the secondary inferior utricle, The antheridium bears at its summit a small lid, formed EMBRYOGENY IN ALGA. 271 from the upper part of the membrane of the androspore. This antheridium, at first unicellular, divides into two cells, which become the mother-cells of the spermatozoids. The whole plastic contents of each mother-cell are employed in the formation of a single spermato- zoid of considerable size. When the spermatozoids are mature then the upper spermatozoid raises slightly the lid of the antheridium (fig. 479, 1, 2, c). In the meantime the female organ is going through a process of development. When its contents are mature, the membrane of the female organ is ruptured all at once a little below its summit, the upper part forming a sort of lid, and the filaments which surmount it are turned to the side by the swelling of the plastic contents (fig. 479, 1, 2, 4). There is thus a space on one side between the lid and the lower part of the female organ. Then the mucous colourless por- tion of the endochrome protrudes from theaperture, and its colour- less cellular membrane presents a distinct lateral opening turned towards the antheridium. When the female organ has undergone these further changes in its con- tents, the lid of the antheridium is completely detached, and allows the upper cuneiform ciliated spermatozoid to escape. This spermatozoid, after mov- / ing around the female organ for some time, enters the open- ing. The spermatozoid reaches the female globule, which is : then fertilised, and seems to 1 ; 2 be absorbed in its substance. Mee After this the female globular body becomes more and more definite, and finally is surrounded by a double membrane. In the cells of another Alga, called Sphzeroplea annulina (fig. 480 ab), there are produced stellate spores, very like the reproductive bodies of Volvox stellatus. In spring the contents of these spores divide into two, then into four or eight parts, which become zoospores. Fig. 479, 1. Entire plant of Zdogoniwm ciliatwm. a, Ordinary cells containing zoospores, which ultimately escape and form new plants. 6, Sporangium, containing spores. c, Androspore fixed on the sporangium, bearing at its summit an antheridium with alid. d, Setiform prolongation of the plant. Fig. 479,{2. Sporangium, with spores. 0, Magnified. c, Androspores bearing antheridium, with the lid at the top. d, Filament bending to the side, so as to expose an opening into the spore-case, by which the spermatozoids enter, 272 EMBRYOGENY IN ALG. These zoospores swim about, and then fix themselves, giving rise to young Conferve. This is a first asexual generation. The young Conferva is a sort of prothallium, for it bears certain sexual organs. One kind of organ presents itself in the form of cells covered by a membrane, pierced with a certain number of apertures, and having contents which become converted into spores. These are the arche- gonia (fig. 480 6). A second kind has a membrane also pierced with several apertures, and contains small mobile baculiform (rod-shaped) bodies. These are the antheridia, with their spermatozoids (fig. 480 a). The spermatozoids come out from the cells, and enter the openings in the spore-bearing cells, and thus fertilise the spores. Saprolegniex, including the genera Achlya, Saprolegnia, and Py- thium, are cellular plants which grow on dead and living animals. The name is derived from sureés, putrid, and Aéyvov, a coloured border. The bodies of flies thrown into water often become covered with these minute thread- like organisms. Gold fish in tanks have their gills sometimes covered with Achlya prolifera. They resemble in appearance the mucors or moulds, and: some have placed them amongst the Fungi. They seem, however, to be more nearly allied to filamentous Algee, such as Vaucheria. At the end of the filaments a cell is formed, which becomes separated from the rest of the filament by a septum. Zoo- spores (fig. 481 a a) are developed, which escape by the bursting of the cell. The filaments of Saprolegniez also produce lateral branches, at the ends of which are swellings, which are divided from the rest of the tissue. In them sacs called oosporangia are formed (fig. 481 0). These are fertilised by the union of cells containing spermatozoids, in the same way as Vaucheria, and oogones (av, an egg) are formed. Thus there are two modes of reproduction—one by asexual zoospores (fig. 481 a b), and the other by sexual antheridia and cosporangia (fig. 481 ¢ d). In the red sea-weeds, called Rhodospermes or Florides, fecunda- tion is effected by antheridia, containing motionless corpuscles, and a peculiar hair-like body called trichogynium (Ogi, hair, yuv7, female). At the base of this latter organ there is a cell which, after fertilisation, is transformed into the cystocarp (dori, a bladder Fig. 480. Fig. 480 a b. Sphwroplea annulina. Male filament, a, consisting of cells with vacuoles, and with spermatozoids which are passing out of the cells by openings in the walls. Female filament, 6, formed by cells containing spores, which are being fertilised by the spermato- zoids, which enter the cells by openings in the walls, and come in contact with the cellular spores, EMBRYOGENY IN ALGA. 273 and xaeqés, fruit), which is sometimes supported on a cellular body called trichophore (dg/E, reiyés, hair, gogedi, I bear). In some cases, as in Nemalion, the fertilisation is direct, the influence of the antheridian cor- puscle being at once conveyed by the trichogynium to the rudiment- ary cell of the cystocarp. In other cases, as in Dudresnaya, the action is less direct—the influence of the antheridian corpuscles being con- veyed by connecting tubes which pass laterally from the base of the trichogynium to numerous fructi- ferous filaments, on which the cystocarps are finally developed. In Floridez there are also bodies called tetraspores (rerecs, four), on account of their being divided into - Fig. 481. four spore-like organs. These are contained in a distinct sac (fig. 482). They are probably concerned in vegetative and not in sexual reproduction. In the brown seaweeds (Fucacez) there are concep- Fig. 482. Fig. 483. Fig. 4840. Fig. 484. Fig. 485, tacles (fig. 483) containing antheridia (fig. 484, a and b) and archegonia (fig. 485), either separate or combined, the plants thus being moneecious or dicecious. Fig. 481. Saprolegnia showing organs of reproduction. aa, Filaments containing asexual zoospores, some of which are being emitted from the end of the cell. 6, Stalked sporangium (oosporangium) ending in a rounded cell c, containing in its interior cells called oogones ready to be fertilised. d, Antheridium coming into contact with the female cell, and sending tubes to the oogonia so as to fecundate them. Fig. 482, Tetraspore, t, of one of the rose- coloured Seaweeds (Callithamnion cruciatum). It is a sac formed by the metamorphosis of the lowermost pinnule of the frond, and contains four germinating spores. Fig. 483. Cell of a conceptacle of Fucus containing spores and abortive filaments, The spores %scape at the opening, 0; other conceptacles contain antheridia. Fig. 484, Antheridia of a Sea- weed (Fucus serratus). a, Antheridium, containing spermatozoids, b, Antheridium with two spermatozoids having vibratile cilia attached. Fig. 485, Archegonium (sporangium) of a seaweed containing pear-shaped spores which germinate, T 274 EMBRYOGENY IN HEPATICA. In Characez, which are aquatic cryptogamic plants found in ponds, there are two fertilising organs, one called, from its rounded form, the globule (fig. 486 g), corresponding to the antheridium ; and another (fig. 486 n), the nucule (nucula, a small nut), representing the archegonium. The globule contains a definite number of cells, which meet in the centre and form a round mass, whence jointed filaments containing spermatozoids arise (fig. 487). The colour of the globule is red. The nucule is a large oval cell (archegonium), round which five Fig. 486. Fig. 487. filaments are spirally twisted, ending at the summit in five or ten tooth-like processes. The central oval cell in the nucule is fer- tilised by spermatozoids from the jointed filaments of the globule coming into contact with it. After fertilisation the nucule drops off and ultimately forms a new plant. While the nucule may be considered as equivalent to the archegonium, it is in reality a com- bination of that organ and a spore. In Hepatice (Liverworts), including Marchantize and Jungerman- nis, the reproductive organs consist of antheridia and archegonia, The antheridia are small cellular sacs of a globular, ovoid, or flask- like form. They have a single or double cellular covering, enclosing viscid matter, in which are developed four-sided cells, in each of which is a small filiform spermatozoid (phytozoon), rolled up in a circular manner, and displaying rapid movements. The spermatozoids are finally liberated, and unrol themselves, appearing as filaments swollen at one extremity, and gradually tapering to the other. In Marchantia (fig. 488) the antheridia occur in the upper side of an elevated disk or receptacle, r. When this disk is cut vertically, as in fig. 489, they are seen at aa, as flask-like cellular sacs separated by air-cavities, cc, which communicate with stomata, ss, In fig. 490 an antheridium is shown discharging its minute cells containing sperma- tozoids. In some Hepaticz the antheridia occur in the substance of the thallus, while in others (as in some Jungermannixe) they appear in the axil of the leaves. Fig. 486. Cellular tubes of Chara, with verticillate branches, from the axil of which proceeds the '‘nucule, n, containing a germinating spore, while below the branch is placed the red globule, g, containing antheridian cells and spermatozoids. Fig. 487. Filament from the globule of Chara, consisting of numerous sperm-cells (phytozoary cells). A sper- matozoid, s, is seen escaping from one of them. EMBRYOGENY IN HEPATICA. 275 The archegonia of Hepatice are either situated in the substance of the thallus, as in Riccia and Anthoceros, or they are raised upon Fig. 489. Fig. 488. stalks, as in Marchantia (fig. 491) and Jungermannie. In Mar- chantia these stalks bear radiated receptacles, r, on the under surface of which the sporangia are placed, which are peculiar bottle-shaped bodies (fig, 492) containing germ-cells. The spermatozoids enter the archegonia, and thus a cell is fertilised, from which the sporangium or spore-capsule, a distinct body, is pro- duced (fig. 491 s), constituting the second generation. In Junger- mannia bicuspidata (fig. 493) there is represented at a an arche- gonium containing an unimpregnated germ-cell, and at 6 an arche- gonium containing an impregnated germ-cell, which is the rudiment- ary spore-capsule. The germ-cell, after fertilisation, shows two nucleated cells, c, and from it, as a second generation, the fruit- Fig. 488, A species of Liverwort (Marchantia polymorpha), with its green thallus, t, bearing a cup-like body, g, in which minute cells or free buds (sporules of some) are seen, and a stalked receptacle, sv. Inthe substance of the disk-like receptaele, r, cells are produced con- taining spermatozoids. These are considered antheridia. Fig. 489. Vertical section of the disk-like receptacle of Liverwort (Marchantia), showing the antheridia, a a, in its substance. These antheridia are flask-shaped sacs containing phytozoary cells. They communicate with the upper surface, and their contents are discharged through it. Between the anther- jdia there are air cavities, c c, connected with stomata, s s, 276 EMBRYOGENY IN MOSSES AND LIVERWORTS. bearing stalk is produced. Around the orifice of the canal leading to the germ-cell and rudimentary spore-capsule are seen numerous sper- matozoids, s s, which have been discharged from the antheridia. Fig. 490. Fig. 491. In Mosses there is a free germ-cell (embryonal cell) at the base of the archegonium. Spermatozoids, from the sperm-cells of the anthe- ridium (fig. 494), reach it, and then it is developed into the sporangium or spore-case (fig. 495), which is the second generation of the plant. The spores produce the leafy plant, bearing antheridia and archegonia. In fig. 496 is shown the confervoid prothallium, p, of a Moss pro- duced from the spore, and bearing buds, a 6, which produce leafy individuals with organs of reproduction. After the contact of these organs, a single cell of the archegonium is developed into the com- plete fruit (theca or sporangium), which is often borne upon a stalk (fig. 495). The complete fruit contains spores, which, when discharged, again develop the foliaceous plant. In leafy Mosses and in Jungermannie there is also an increase by buds. The confervoid filament produced by the spore gives origin to a number of buds (fig. 496), whence leafy stems proceed, and Fig. 490. Antheridium of Liverwort (Marchantia) discharging its sperm-cells, that is, cells containing spermatozoids. Fig. 491. Thallus of Liverwort (Marchantia polymorpha), bearing a stalked fruit, s, which is the product of the impregnated cell of the archegonium. The receptacle at the apex of the stalk bears on its under surface sporangia containing spores and elaters. The spores, when germinating, produce a thallus, on which antheridia and archegonia are formed. Fig. 492, Pistillidium or archegonium of Liverwort (Mar- chantia), containing in its interior a cell, which is impregnated by the spermatozoids of the antheridium. EMBRYOGENY IN MOSSES AND LIVERWORTS. 277 these leafy stems also produce buds or gemme, called innovations, There is thus a multiplication by sexual reproduction and by gem- mation, as in higher plants, Fig. 496. Fig. 495. Fig. 493. Archegonia of Jungermannia bicuspidata. a, Unimpregnated archegonium, with a tube leading to a cavity, near the base of which is a cell. b, Archegonium after impregnation, with the cell divided into two nucleated portions. This double nucleated body is the rudiment of the fruit-bearing stalk. At the apex of the canal leading to the cell are seen spermatozoids, s s. Fig. 494. The male organs of a Moss (Polytrichwm). a, Antheridium containing sperm-cells, two of which are seen at c. These spérm-cells contain spermatozoids, which are discharged so as to impregnate the archegonium. Surrounding the antheridium there are filaments or paraphyses, p. Fig. 495. Sporangium of a Moss (Polytrichwm), supported on a stalk. This stalked sporangium is produced by the impreg- nated cell of the archegonium, It constitutes the second generation. Fig. 496. Con- fervoid filament forming the prothallium, » (exothallium), of a Moss (Punaria hygrometrica), consisting of a congeries of cells arranged in a filiform manner. This prothallium originates from the spore, and bears a bud, a, and a young stem, b, from the base of which roots proceed, Fig. 497. End of fructiferous branch of Lycopodium clavatum, common Club- moss, The leafy branch, J, ends in a stalk bearing two spikes of fructification, f 278 EMBRYOGENY IN LYCOPODIACEA. Lycopodiacew, Club Mosses (fig. 497), have sporangia which are either all alike as in- Lycopodium, or of two forms as in Selaginella. The dimorphic sporangia consist of mécro-sporangia (fig. 498), (wimeéc, small), containing numerous granules (microspores or anthe- ridia), (fig. 499), and macrosporangia (fig. 500), (waxeés, long), called by some megasporangia (wéyas, great), or oophoridia (wiv, an egg, Qogéw, I bear), of a large size containing often four macro- spores or megaspores, in the interior of which a cellular prothallus is formed (fig. 501, p), on which archegonia are developed (fig. Fig. 502. Fig. 503. 502 a). In the microspores of Isoetes and Lycopodium there is a sort of male prothallium bearing antheridia with spermatozoids. No germination has been observed in the microspores of the genus Lyco- podium. The process of impregnation in Lycopodiacee is supposed Fig. 498. Antheridium of a Club-Moss (Lycopodiwm), containing microspores, which are cells containing spermatozoidal cellules, as seen in fig. 499. Fig. 499. Small spore (pollinic spore) of a Lycopod (Selaginella helvetica), bursting and discharging cellules, c, containing spermatozoids. Fig. 500. Oophoridium or macro-sporangium of a Club-Moss (Lycopodium), opening and showing four large spores in its interior. These macrospores or megaspores contain a cellular prothallium or endothallium in their interior, bearing archegonia. Fig. 501. Macrospore discharged from the oophoridium of a Lycopod (Selaginella Mertensit), with the outer coat removed to show the young cellular prothallium, p, at the upper end. Fig. 502. Vertical section of the prothallium and upper half of a large spore of a Lycopod (Selaginella denticulata). There are several archegonia, and in one of them, at a, there is a central free cell, whence the leafy frond ultimately proceeds. Fig. 503. Vertical section of a small portion of the prothallium and upper part of the large spore of a Lycopod (Sela- ginella denticulata), showing the embryo, e¢, developed from a central cell of one of the archegonia, a, carried down by the growth of the suspensor, so as to be imbedded in the cellular tissue at the upper part of the spore. EMBRYOGENY IN MARSILEACEE AND FERNS. 279 to take place by the spermatozoids of the small spores coming into contact with the large spore after the coat of the large spore has burst at its apex, so as to expose the cellular prothallium and its archegonia (fig. 502 a). The free central cell of the archegonium then enlarges, divides, and elongates into a filament, which grows down into the prothallium (fig. 503). A suspensor is thus formed, at the end of which is the embryo, ¢, imbedded in the cellular tissue at the upper part of the large spore. The embryo _finally produces its radicle and its bud, which is developed as the leafy frond. — In Rhizocarps (Marsileacez) there are also antheridia and arche- gonia. The former are sacs containing small spores, which produce inside a small prothallium, on which are borne antheridia containing spermatozoids. The latter are sporangia containing large spores igo Fig. 504, Fig. 505. Fig. 506. which ‘produce a prothallium like that of Lycopods, on which archegonia appear. The prothallium usually produces only one central archegonium, the spermatozoids get access to the arche- gonia, and thus the young plant is produced. In Ferns there is a prothallus bearing antheridia and archegonia atthe same epoch. It is produced by the spore during its germination, and consists of cells, as shown in fig. 507. The antheridia occur on the under surface of the prothallus, and they consist of a cellular papilla having a central cavity (fig. 508). This cavity contains free cellules, which are discharged by a rupture at the apex, b, and each of these little cellules, in bursting, gives exit to a ciliated spiral filament (spermatozoid), (fig. 509), which swims actively in water, advancing with a rotatory motion through the water when seen under the microscope. The archegonia (fig. 510) exist on the under side of the prothallus, near the notch of the border. They are less numerous than the antheridia (varying from three to eight), and consist of cellular papilles formed by ten or twelve cells. They are larger than Fig. 504. The small spore of a Rhizocarp (Pilularia globulifera, Pillwort). The inner coat is protruded, and the outer coat has burst, so as to discharge cellules containing sper- matozoids. Some of the spermatozoids are separate, and are seen coiled up in a spiral form. Fig. 505. Large spore of a Rhizocarp (Marsilea, Pepperwort), which contains a cellular pro- thallium bearing archegonia, The mammillary projection is the point whence the gem- mation of the embryo proceeds after impregnation, Fig. 506. Vertical section of prothal- lium of a Rhizocarp (Pilularia globulifera), containing a central archegonium, u, before impregnation. bs 280 EMBRYOGENY IN FERNS. the antheridia, and have a central canal, a, leading down to a large globular cell, c, imbedded in the substance of the prothallus, and containing the embryo-germ, ¢. The canal is closed at first, and then opens, The spermatozoids enter the archegonial canal and fertilise the germ-cell. After a time this cell divides and gives rise to the Fig. 510, Fig. 511. ” embryonic body, whence the stem of the Fern arises (fig. 511 /). The life of the sporangiferous plant is indefinite, as seen in Tree Ferns, while the prothallus is of very short duration. Thus in Ferns the spores contained in the sporangium form the prothallus without impregnation, while this latter process is necessary for the development of the germ, which gives rise to the leafy sporangiferous Fig. 507. Cellular prothallium (exothallium) of a Fern (Pteris longifolia), produced by a spore, s, and giving off a root, 7, at one end. It consists of numerous cells, and it gives origin to antheridia, and pistillidia or archegonia, Fig. 508. Antheridia from the prothal- lium of the Common Brake (Pteris aqwilina). a, An unopened antheridium ; b, antheridium bursting at the apex, and discharging free cellules, each containing a spermatozoid; ¢, antheridium after the discharge of the cellules. Fig. 509. A spermatozoid with cilia, discharged from a cellule in the antheridium of the Forked Spleenwort (Asplenium septen- trionale). Fig. 510. Archegonium of the Forked Spleenwort (Asplenium septentrionale) immediately after impregnation. a, Canal leading to the ovule or large cell, c, at the base of the archegonium ; e, nucleated embryonic cell, whence the sporangiferous frond proceeds. Spermatozoids from the antheridinm reach the canal of the archegonium, and impregnate the ovule. Fig. 511. Young plant of a Fern (Pteris paleacea), showing the commencement of the sporangiferous frond, f, arising from the impregnated ovule in the archegonium ; the prothallium, p, being still attached. EMBRYOGENY IN EQUISETACEAH AND FERNS. 281 frond ; while in Mosses the spore forms the prothallus and the leafy stem without impregnation, and this operation gives rise to the formation of the stalked theca. s The reproduction of Equisetacez (fig. 512), Horsetails, resembles much that of ferns. Their spores, which are surrounded by hygrometric filaments, called elaters, germinate and form a lobed prothallus bearing antheridia at the top of its lobes and archegonia at its base. The an-- theridia appear as ovoid swellings containing at first globules, which ultimately are developed as spermatozoids (antherozoids).. The archegonia consist of globular bodies, terminated by a long neck with a four-lobed opening at the top. The spermatozoids enter by the opening and fertilise a cell in the archegonium, which ultimately constitutes the germ of the new plant. Ferns, Ophioglossacese and Equisetacex, are called isosporee (00s, equal), because they produce a single kind of spore, which in its turn gives origin to a pro- thallus furnished with chlorophyll and roots, and capable of independent existence. On the same prothallus, or on two neighbouring ones, antheridia first of all origin- ate, and when mature emit spermatozoids, then follow archegonia generally formed of a central cell, to which access is gained by a canal opening outwards. Fecun- dation being effected by the entrance of spermatozoids into the archegonium, the first period is closed, and then commences the asexual generation. The embryo is developed at first in the substance of the prothallus, but afterwards becomes disengaged from it, and passes through the different phases of its. development. Finally, the second generation terminates its evolution by the development of the organs of multiplication as spores, which always originate from a normal or modified leaf. Fig. 512. Fertilisation or Fecundation in Phanerogamous or Flowering Plants, In flowering plants the organs of reproduction are stamens and- pistils, the former representing the male element, and the latter the female. The cellular pollen (sperm-cells) produced by the former must be applied to the cells contained in the latter (germ-cells), in order that the embryo plant may be formed in the seed. Fig. 512. Fructification of Equisetum maximum, Great Water Horsetail, showing the stalk surrounded by membranous sheaths, ss, which are fringed by numerous processes or teeth. The fructification, f, at the extremity, is in the form of @ cone bearing polygonal scales, under which are spore-cases containing spores with clavate filaments, 282 FERTILISATION IN FLOWERING PLANTS. In flowering plants various provisions are made for insuring the application of the pollen to the stigma. The saccharine secretions of the flower, the comparative length of the stamens and pistils, their position, and the dehiscence of the anthers, are all regulated with this view. The existence of spiral cells in the endothecium has reference apparently to the bursting of the anther and the scattering of the pollen. The number of pollen-grains produced is also very great. In a floret of wheat Wilson reckoned about 7000 pollen-grains. Hassall says that a single head of Dandelion produces upwards of 240,000, each stamen of a Peony 21,000, a Bulrush 144 grains by weight. It has been stated that a single plant of Wistaria sinensis produced 5,750,000 stamens, and these, if perfect, would have contained 27,000,000,000 pollen-grains.* In a single flower of Maxillaria F. Miiller estimated the pollen-grains at 34,000,000. This same flower produces 1,756,000 seeds. In Orchis mascula the pollen-grains in a single flower have been estimated at 120,000. In the case of Ever- greens, such as Firs, the quantity of pollen is enormous, apparently to insure its application notwithstanding the presence of leaves. The pollen from pine forests has been wafted by the winds to a great distance, and sometimes falls on the ground like a shower of sulphur. It is thus that some kinds of coloured rain, occasionally witnessed, may be accounted for. The pollen powder transmitted to considerable distances remains floating in the air till carried down by a passing shower. The quantity of pollen required for impregnation varies, Koel- reuter says, that from fifty to sixty grains of the pollen of Hibiscus Trionum are required to fecundate the fruit completely, containing about thirty ovules. The ovary of Nicotiana, Datura, Lychnis, and Dianthus, according to Gertner, may be completely fertilised by the pollen of a single perfect anther. In Geum, from eight to ten anthers, out of eighty-four to ninety-six contained in each flower, are sufficient to fertilise from eighty to one hundred and thirty ovules contained in the ovaries, In many trees in which the organs of reproduction are in separate flowers (as in Hazel and Willow), the leaves are not produced until fertilisation has been effected. The protection of the pollen from the direct influence of moisture is effected by the closing of the flowers, by the elasticity of the anther-coat only coming into play in dry * The following estimate was made of the amount of flowers, stamens, etc., in a single specimen of Wistaria sinensis :— Number of clusters of Flowers .. 9,000 — snaivigual Hlowers 675,000 —Petals.. d — Stamens.. — Ovules .. For the purpose of fertilising these pyilea the dations: if perfect, ane have contained about 27,000,000,000 pollen-grains, or about 7000 grains to each ovule. FERTILISATION IN FLOWERING PLANTS. 283 weather ; and in aquatics, either by a peculiar covering and structure as in Zostera, or by the flowers being developed above water, as in Nymphea, Lobelia, Stratiotes, and Hottonia. In Vallisneria spiralis (fig. 513), a plant growing in ditches in the south of Europe, the stami- niferous flowers are detached from the male plant, float on the surface of the water, and scatter their pollen ; while the pistilliferous plant, b, sends up a long peduncle, which accommodates itself to the depth of the water by being spiral, and bears on its summit the flower with the pistil. By this means the two organs are brought into contact, and fertilisation is effected. Lagarosiphon muscoides, an aquatic plant from Africa, shows similar phe- nomena in regard to impregnation as are seen in Vallisneria. When continued wet weather comes on after the pollen has been matured, and has begun to be discharged, it often happens that little or no fruit is produced. In flowers where the anthers burst in succession, the injury done by moisture is less likely to extend to all. Stamens are protected in various ways from wind and moisture. In Iris by the petaloid divisions of the style, in Phyteuma by the upper united part of the corolla, in Trollius by the sepals turned inwards, so as to form a, ball (hence the name globe- flower), and in Arum by the spathe (fig. 260, p. 178). In many flowers the perianth gives shelter to the stamens. In Orchids the pollen is well protected. In some plants the stamens, at a certain period of their develop- ment, move towards the pistil, before the contents of the anther are discharged. In Parnassia palustris (fig. 514) and Rue they do so in succession. In Kalmia the anthers are contained in little sacs or pouches of the corolla, until the pollen is mature, and when the expansion of the corolla and the elasticity of the filament combine to liberate them, they spring towards the pistil with a jerk. In Parie- taria officinalis, and in the Nettle, the spiral filament is kept in a folded state until the perianth expands, and then it rises with elastic force and scatters the pollen. Similar phenomena are observed in the Cornus canadensis. In the various species of Barberry the inner and lower part of the filament, is irritable, and when touched it causes the stamen to move towards the pistil. The anther opens by recurved Fig. 513. Male and female plants of Vallisneria spiralis. a, The male plant, the flowers of which are detached, and rise to the surface of the water so as to mature its pollen and scatter it ; 0, the female plant, which remains fixed in the mud, and sends up a spiral peduncle, which uncoils according to the depth of the water, and bears the pistil- liferous flowers above the water, so as to allow the pollen to be wafted upon them. w ‘Fig. 518. ob 284 FERTILISATION IN FLOWERING PLANTS. valves, which are covered with pollen-grains. The species of Stylidium have their anthers and stigma seated on a column, the base of which is slightly swollen and irritable. When a stimulus is applied, this column passes with considerable force from one side of the flower to the other, rupturing the anther-lobes, and thus aiding in fertilisation. In some plants the pollen is scattered by the wind, and they are called anemophilous (dvewos, wind, and g/Ao¢, love); while in other cases animals are the agents employed in its distribution, and the plants are called zoophilous (@wov, animal). It has been ascertained that self-fertilisation is by no means common in flowers, that is to say, the pollen is not always applied to the pistil of the flower in which it is produced. We constantly find that pollen produced by the anther of one flower is applied by the medium of wind or insects to the pistil of another flower on the same plant, or on different plants. This is seen very evidently in moncecious and dicecious plants. It also occurs in dimorphic plants where there is a difference in the development of the stamens and pistil in the case of individual flowers; as is well seen in some species of Primula, and of Linum. Flowers visited by insects are often highly coloured and odoriferous, and secrete honey-like matter. Night-flowering and night-smelling plants attract crepuscular insects. These may be illustrated by Pelargonium triste, Hesperis tristis, and Nyctanthus Arbor-tristis, Stapelias (carrion flowers) by the fetid odour of their flowers attract blow-flies, which deposit their eggs amongst the hairs of the flower. The eggs in due time are hatched, and then the maggots in search of food press the pollen masses downwards to the stigma and so cause fertilisation. In Oxalis Acetosella the flower is erect during the day, and is open to the visits of insects ; it describes an arc of more than 100 degrees when the sun sets, and finally has its opening directed to the ground. The pollen in the case of plants fertilised by insects is sometimes elliptical with three or more longitudinal furrows, as in Ranunculus Ficaria, Aucuba japonica, and Bryonia dioica; at other times it is spherical or elliptical, and covered with projecting processes (echinate), as in many Composite, Malvacez, and Cucurbitacee; or, thirdly, the pollen grains are attached together by threads or a viscid secretion, as in Richardia Rhododendron and CEnothera, In plants fertilised by the wind, as in most grasses, Hazel and Populus balsamifera, the pollen is almost perfectly spherical, and has no processes, and is generally light and dry. Dr. Dyer remarks that while in Crucifere fertilisation is generally effected by insects, in Pringlea antiscorbutica (Kerguelen Island Cabbage), which differs from the plants of the order in having no petals, no honey glands, an exserted style and papillose stigma, fertilisation is effected by the wind. It has been stated by some authors that in the case of the cereal grains impregnation is effected before the flowers are open, and that thus self-fertilisation takes place, HETEROMORPHIC FERTILISATION. 285 This has been specially noticed by Hildebrand in the case of barley, and Mr. Stephen Wilson states that the same thing occurs in wheat and oats. Delpino remarks that in an ear of barley there are certain flowers differently constructed from the rest, in which cross-fertilisation is possible, and that in the oat the process varies according to the weather. In fine warm weather the flowers open freely, and cross- fertilisation is favoured ; while in cold wet weather they remain closed, and self-fertilisation is inevitable. In rye, fertilisation from the pollen of other flowers is provided for.* Certain flowers of Primrose are called pin-eyed, having a long style with the rounded stigma projecting beyond the tube of the corolla, and standing high above the anthers, which are situated halfway down the tube; others are called thumb-eyed, having a short style, with the anthers attached at the mouth of the tube, and therefore high above the stigma. These flowers occur on distinct plants. Such species are dimorphic, and may be conveniently called diceciously- hermaphrodite—that is, having two kinds of hermaphrodite flowers on distinct plants, Efficient fertilisation is only attained by the application of the pollen from stamens of a given length to styles of _ a corresponding length. The short styles are of the same length as the short stamens, and the long styles as the long stamens, and it appears that the best fertilisation and the greatest number of seeds are produced by the application of the pollen of the short-styled flowers to the long-styled. This is called heteromorphic fertilisation, in contradistinction to homomorphic where the pistil is fertilised by the pollen of its own flower. In the Ipecacuan plant (Cephaelis Ipecacuanha) dimorphic flowers occur of a similar kind, Lythrum Salicaria is trimorphic ; that is, it presents three forms of flowers. Each of these has stamens and pistils, each is distinct in its pistil from the other two forms, and each is furnished with two sets of stamens differing from each other in appearance and function. There are three lengths of stamens—long, medium, and short—but. two lengths only occur in the same plant ; and there are also three lengths of styles, but they are not associated with stamens of corresponding length. There are then three forms of flowers—1l. With short and medium stamens, and long style; 2. With short and long stamens, and medium style; 3. With medium and long stamens, and short style. The stigma is best fertilised by pollen from stamens of lengths corresponding to the styles. Two of the three hermaphrodite forms must co-exist, and the pollen must be conveyed reciprocally from one to the other, in order that either of the two may be fully fertile ;, but unless all three forms co-exist there will be waste of two sets of stamens, and the organisation of the species as a whole will be im- perfect. On the other hand, when all three hermaphrodites co-exist, * See Stephen Wilson’s paper in Trans. Bot. Soc., Edin., 1874, 286 DICHOGAMOUS PLANTS. and the pollen is carried from the one to the other, the scheme is perfect. The three forms are divided according to their styles into long-styled, mid-styled, and short-styled. Such plants may be called triceciously hermaphrodite. The fertilisation is effected by the agency of insects, The insect in passing from flower to flower will brush against a stigma at a given level with the same part of its head or body which has brushed off the pollen from an anther at a corre- sponding level. The object of all these arrangements is the pre- vention of close inter-breeding. Homomorphic unions, where a pistil is, supplied with pollen from its own flower, or from a flower of the same form, result either in very diminished fertility, or, as in the dimorphic species of Linum (Flax), in absolute sterility. The same object—namely, the prevention of close inter-breeding— may be effected by other means ; sometimes, as in Orchidaceee (fig. 317, p. 205), and Asclepiadacese (figs. 385, 386, p. 230), by the mechanical arrangement of the parts of the flowers, and, more especially, the consistence of the pollen, being such that fertilisation cannot occur without the agency of insects, which carry the pollen masses (pollinia) from one flower to another. In the species of Orchids, such as Orchis mascula, the pollen masses (fig. 387, p. 230) have each a caudicle, which is firmly attached to a viscid disk, con- sisting of a minute oval or rounded piece of membrane, with a ball of viscid matter on its under side. These balls are contained within a cup-like rostellum, the lip of which is easily depressed by contact with a foreign body, such as the proboscis of an insect. The pollinia be- come thus attached to the proboscis. At first they stand erect, but ultimately, by the contraction of the minute disk, they bend down- wards and forwards towards the point of the proboscis. In this way the pollen is in a position to be at once applied to the stigma when the insect visits another flower, and thus fertilisation is effected. The prevention of close inter-breeding is also accomplished in many cases by the physiological condition of the parts concerned in fertilisa- tion, as occurs in what are called Dicho- gamous plants—that is, plants in which the stamens and stigmas of the same flower do not reach maturity at the same time— the stamens being matured first in what are called protandrous plants, and the stigmas first in protogynous plants. (See notice of Protandrous and Protogynous plants, at page 212.) In Parnassia palus- tris (fig. 514) the stamens move in suc- Fig. 514. Flower of the Grass of Parnassus (Parnassia palustris), the stamens of which jnove in succession towards the pistil, and discharge their pollen. In the figure some stamens are seen applied to the pistil, and others removed from it. - FERTILISATION EFFECTED BY MEANS OF INSECTS. 287 cession towards the pistil, and after the pollen has been discharged they curve back to the petals. But the stigma is not perfect at that time. It becomes developed after the pollen has been discharged and the anthers have retired. It requires the agency of insects to effect complete fertilisation. The pollen is discharged on the part visited by insects, and they take it up on that part of their bodies which touches the perfect stigma in other flowers, and thus fertilisation is effected. In Lobelia we have an instance of the stamens being com- plete and the pollen discharged before the stigma is perféct. After the pollen has been discharged, the style elongates and carries the stigma upwards beyond the syngenesious anthers, and then the stigma becomes perfect, so as to be ready for the pollen applied by insects, Both these flowers are Protandrous. In Euphorbia jacquiniflora, several days before the stamens burst through the involucre which closely invests them, the pistil with its ovary on the long pedicel has protruded itself beyond, expanded its stigma, and received pollen from neighbouring flowers. It is there- fore Protogynous, ; In the case of Aristolochia Clematitis (fig. 515), the flowers, as long as the essential organs are in a state fit for fertilisation, stand erect, with their oblique mouth turned outwards, by which an insect can enter easily, and pass down the tube till it comes to the column bearing the stamens and stigma. It is prevented from returning by inverted hairs in the tube. It is detained in the tube till the pollen is fully matured, and then the hairs collapse so as to permit its escape. It carries with it pollen grains, It then visits a flower where the stigma is matured, and which presents the open mouth of the tube in an erect condition, and on reaching the cavity : Fig. 515. Flowering stalk of Common Birthwort (Aristolochia Clematitis). Fertilisation is effected by insects. 288 FERTILISATION EFFECTED BY MEANS OF INSECTS. at the bottom of the tube, fertilises the pistil with the pollen which it has carried with it from another flower. This plant is proto- gynous, the stigma being matured before the stamens. When the flower is duly fertilised it sinks down, no longer presenting a tempting orifice for the entrance of insects. If no insect visits the chamber, then the stigma passes its maturity before the pollen of its own flower is ripened, and no fertilisation takes place. Orchids with very long nectaries, such as Anacamptis, Gymna- denia, and Platanthera, are habitually fertilised by Lepidoptera, while those with only moderately long nectaries are fertilised by bees and Diptera. The length of the nectary is correlated with that of the pro- boscis of the insect which visits the plant. Orchis Morio has been seen fertilised by the hive-bee (Apis mellifica), to some of which 10 or 16 pollen-masses were attached; by Bombus muscorum, with several pollinia attached to the bare surface close above the mandibles ; by Eucera longicornis, with 11 pollinia attached to the head, and by Osmia rufa. Empis livida has been seen fertilising Orchis maculata. . In Listera (fig. 317, p. 205) the viscid mass of the rostellum bursts with force, and then allows the pollinia to escape. The nectar in some species of Orchids is secreted between the outer and inner mem- brane of the nectary, and bees puncture the inner lining of the nectary and suck the fluid contained between the coats. In some Orchids, as in Neotinea intacta, there is evident self-fertilisation, although there is also provision for fertilisation by insects. So also in Ophrys apifera, Gymnadenia, Platanthera, Epipactus, Cephalanthera, Neottia, Epidendrum, Dendrobium. In Disa grandiflora the weight of the pollen masses bends the caudicle. In this plant the posterior sepal secretes nectar. In Coryanthes, Gongora, Catasetum, Stan- hopea, etc., the extraordinary crests and projections on the labellum are gnawed by insects, and while doing so they are sure to touch the viscid disk of the pollinia and remove them. The flowers of these plants exhibit remarkable animal forms, probably with the view of attracting insects. It has been remarked that in Orchids the forms of the perianth resemble those of the insects belonging to the native country of the plant. The flowers also secrete a large amount of saccharine matter, and are odoriferous ; their pollen masses are very easily detached, and are very adhesive. All these circumstances seem to be connected with their mode of impregnation. In Asclepiadacez, which have also peculiar pollinia (fig. 386, p. 230), insects are attracted by the odour of the flowers (sometimes very fetid, as in Stapelia), as well as by saccharine matter. Darwin states that bees always alight on the left wing petal (ala) of the scarlet kidney-bean, and in doing so depress it ; and this acts on the tubular and spiral keel petal (carina), which causes the pistil to protrude. On the pistil there is a brush of hairs, and by the FERTILISATION EFFECTED BY MEANS OF INSECTS. 289 repeated movement of the keel petal the hairs brush the pollen beyond the anthers on to the stigmatic surface. He found, in many instances, that if the plants were protected from bees, the number of fertile seeds produced was much smaller than when the bees were freely admitted. In the common bean the bees alight on the wing petals (alee), and cause the rectangularly-bent pistil and the pollen to protrude through the slit of the carina. : In Erica Tetralix each anther-cell adheres, just in the part where its opening is situated, to the corresponding part of the adjoining cell of the next placed anther in the circlet. Thus the pore of a cell, say the right cell of an anther, is, so to speak, closed by the pore of the left cell of the next adjoining anther, and so on all the way round. A very little power, however, dislocates the chain of anthers ; a slight pressure on the antherine processes or spurs effects this, An insect accomplishes this easily, and thus its head becomes covered with pollen and applies it to the stigma of another flower. Polygala is one of the flowers in which a provision is made for insect fertilising. ‘The corolla consists of five petals united into one piece and folded in the form of a two-lipped tube. The lower lip has a sort of cup-shaped appendage, with a beard of gland-like bodies ; this lip opens in front by a narrow vertical slit. The filaments are united, and the stamens expand within the cup of the lower lip into a two-lobed membrane crowned by the anthers, The pistil has two stigmas,—one is placed at right angles to the upper side of the style and is perfect, the other is transformed into a spoon-shaped petaloid pro- longation of the pistil reaching to the opening of the lower lip of the corolla, and dividing the interior of the flower into two cham- bers, in the lower of which are the stamens, which are thus separated from the true stigma, The entrance to the flower is closed by hairs pointing outwards and meeting in front, on the mouse-trap principle. A narrow passage is left open above the petaloid stigma. On each side of the interior of the tube of the corolla, above the style and just behind the true stigma, is a group of white hairs pointing down. the tube and meeting above the style. An insect lights on the beard, finds a narrow passage leading over the stigma into the upper chamber. It is prevented by hairs on the corolla from returning, and is obliged to crawl out through the lower chamber and over the stamens, and thus carries the pollen to other flowers. The calyx, at first tempting to insects, gradually assumes a green colour, and closes over the ripen- ing seed-vessel.” (Hart.) In Serophulariacez and Labiate (figs, 324, 325, p. 207) the axis of the flower is horizontal, and the stamens are approximated beneath the upper lip of the corolla, An insect in passing separates the anthers, and causes the pollen to fall from them, and thus transports it to a more advanced flower. In some Leguminose the U 290 CHANGES IN STYLE AND STIGMA. insect touches the back of the keel, which throws itself hastily back- ward, and the insect receives a few grains of pollen, with which it impregnates a neighbouring flower. In Fumariacez the stamens and pistil are enclosed between two petals. At the base of the petals, which is prolonged into a spur, there is a quantity of nectar which attracts insects. To reach this an insect must pass between the two petals, the upper parts of which, being borne upon a sort of hinge, separate easily ; then the insect is covered with pollen, which is applied to the stigma. Hermann Miiller states that there are two forms of Euphrasia offici- nalis in which the mode of fertilisation is different. In the large form there is provision for insect fertilisation or cross-fertilisation ; while in the smaller-flowered form there is regularly self-fertilisation. In Rhinanthus Crista-galli there are also two forms, one small and the other large. In the former there is self-fertilisation, while in the latter this is not the case, as the stigma so far overlaps the anther as to render self-fertilisation impossible. Other animals, besides insects, are instrumental in distributing pollen. Humming-birds, when inserting their bills into the nectaries of plants in some countries, carry the pollen on their head feathers from one flower to another. They are said to act as pollen-distributors in the case of a species of Erythrina in Nicaragua. In Marcgraavia nepenthoides there are peduncular pitchers below the flowers con- taining a sweet liquid, attracting insectivorous birds which come and feed on their contents, and in so doing burst the anther and carry the pollen to other plants. While the pollen is being elaborated, the stigma is also under- going changes. It becomes enlarged, and secretes a viscid, usually saccharine, matter, ready to detain the pollen-grains when they are discharged. In Goldfussia anisophylla, and in species of Campanula, as C. media, C. Rapunculoides, C. Trachelium, C. rotundifolia, the style is covered with collecting hairs (fig. 516), which appear to aid in the application of the pollen. In the first-mentioned plant a remarkable curvation of the style takes place, so as to make the stigma come into contact with the hairs. In Campanula the style is at first slightly longer than the stamens, but it soon becomes twice their length, and during its elongation the hairs upon it brush the » pollen-grains out of the anther-cases. The stigma consists of two branches, which are at first erect and closely applied to each other, but afterwards, by changes in the cells, become revolute. This completely developed state of the stigma does not occur until some time after the pollen of its own flower has been Fig. 516, Style of a species of Bellflower (Campanula), covered with hairs, which brush out the pollen from the anthers, Fig. 516. FERTILISATION IN GYMNOSPERMS. 291 discharged. The plant is dichogamous and requires the ae of another flower to fertilise the pistil. In rare instances, as in the Sea-pink (Armeria maritima), the conduct. ing tissue of the style at its lower part becomes elongated so as to pass into the ovary, and ultimately comes in contact with the ovule, when impregnation takes place (fig. 517). The length of time during which the pollen re- tains its vitality, or power of effecting fertilisation, varies in different plants. According to Geertner and others, the pollen of some species of Nicotiana retains its vitality only for forty-eight hours ; pollen of various species of Datura, two days; pollen of Dianthus Fig. 517. Caryophyllus, three days; pollen of Lobelia splendens, eight or nine days; pollen of Cheiranthus Cheiri, fourteen days; pollen of Orchis abortiva, two months ; pollen of Candollea, one year; pollen of Date Palm, one year or more. Michaux says that in some Palms, as Date and Chameerops humilis, the pollen may be applied successfully after having been carefully kept for eighteen years. The pollen retains its vitality longer when not removed from the anthers ; and the finer it is, the more quickly it loses its fecundating property. In most flowering plants the pollen is applied directly to the stigma, but in some cases when the plants are Gymnospermous, that is, have no proper ovarian covering, and no stigma, the pollen is applied directly to the ovule. The pollen then undergoes changes ‘by the formation of tubes, through which the fovilla passes in order to come in contact with the minute cells in the ovule. The matter called fovilla covered by the intine consists of minute molecules, which often exhibit movements, to which the term molecular has been applied. Embryogenic process in Gymnospermous Flowering Plants. In Gymnospermous plants, such as Coniferze (Firs and Pines, fig. 518) and Cycadacez (fig. 519), impregnation is effected by direct contact between the pollen and the ovule. There is no true ovary bearing a stigma. Such is the view taken by many botanists. There are however others of equally high authority who do not adopt this opinion, and who look upon the so-called outer covering as not solely composed’ of the spermoderm, but as formed partly of it and partly of the ovarian coat. Some speak of the ovuliferous leaves in Cycads as being open carpels, and they also look , Fig. 517. Ovary, ov, of Sea-pink (Armeria maritima), in which the ovule is suspended by a curved cord, cor, and the conducting tissue, s, of the style elongates in a downward direction, 292 FERTILISATION EFFECTED BY MEANS OF INSECTS. upon the bracts of Conifers in the same light. In these cases there is no evidence of the presence of a stigma, Gmetacex seem to form a link between Cycads and Conifers. They have an open ovary without a HT Fig, 518. Fig. 519. style or stigma. The name of Archisperms (deyf, beginning, origue, seed) has been given by some to Gymnospermous plants; while the term Metasperms (werd, after) has been applied to Angiospermous plants. These views will be noticed when the natural orders are described. In treat- ing of the embryogenic process it is probably not of much importance which view we adopt. The ovules of the so-called Gymnosperms (fig. 520 ov, and fig. 521) consist of a nucleus (fig. 521 a) covered by one or more integuments, and having a large micropyle (fig. 520 mic, and fig. 521m). In the delicate cellular nucleus (fig. 521 a) there is developed an embryo- sac, 6, sometimes more than one, as in the Yew tribe. The pollen-grains enter the large micropyle and come into contact with the nucleus, and then send their tubes into its apex (fig. 522 c). This process sometimes requires several weeks or months, After this the embryo-sac (fig. 522 6) becomes gradually Fig. 518. A Coniferous tree, the Stone-pine, which belongs to the Gymnospermous divi- sion of Phanerogams, the seeds being {naked, that is, not contained in an ovary with a stigma. The seeds are in cones covered by scales. Fig. 619. A Cycadaceous plant (Cycas revoluta), belonging also to the Gymnospermous division. The seeds in Cycads are produced on the edge of abnormal leaves or on the lower side of scales of cones. Fig. 520, Female flower of a Pine, consisting of a scale, eca, and two ovules, ov, attached to its base ; mic, the foramen of the ovule. The ovules are naked, not being contained in a true ovary. Fig. 520. EMBRYOGENY IN GYMNOSPERMS. 293 filled with cellular tissue or endosperm cells, and at the same time enlarges. This development of endosperm cells occupies frequently a long time, especially in the Abietinese, which require two years to vipen their seeds. After the embryo-sac has become filled with cellular tissue, certain cells at the micropylar end of the sac enlarge and form the corpuscles of Brown, the secondary embryo-sacs of Mirbel and Spach (fig. 523 d), Each corpuscle is at first separated Fig. 521. Fig. 522, Fig. 523. from the inner surface of the embryo-sac by a simple cell, which after- wards divides into four by the formation of two septa crossing each other; then a passage is formed between the inner angles of these cells leading to the corpuscle. In the cavity of each corpuscle free cells appear. After the corpuscles become evident, the pollen tubes resume their growth, pass through the tissue of the nucleus, and reach the outside of the embryo-sac, one over each corpuscle. The tubes then perforate the membrane of the embryo-sac, reach the canal be- tween the four cells, and come into contact with the corpuscle (fig. 523 d). A cell at the lower end of the corpuscle then enlarges, and forms the embryonal vesicle. A free cell in the vesicle divides into eight cells by vertical and transverse septa, and these together consti- tute a short cyclindrical cellular body (fig. 524), the pro-embryo, as it is called by Hofmeister. The four lower cells of this pro-embryo, by the elongation of the upper ones (fig. 525), are finally pushed Fig. 521. Vertical section of the ovule of the Austrian Pine (Pinus austriaca), showing the nucleus, a, consisting of delicate cellular tissue containing deep in its substance an embryo-sac, b, formed before impregnation by the coalescence of a vertical series of a few cells. The micropyle, m, is very wide, and through it the pollen-grains come into contact with the summit of the nucleus, into the substance of which they send their tubes. Fig. 522. Vertical section'of the ovule of the Scotch Fir,(Pinus sylvestris) in May of the second year, showing the enlarged embryo-sac, 6 (full of endospermal cells), and pollen-tubes, c, penetrating the summit of the nucleus after the pollen has entered the large micropyle of the ovule. Fig. 523, Vertical section of the embryo-sac, 6, and of part of the nucleus, a, of the ovule of the Weymouth Pine (Pinus Strobus), At the micropylar end of the embryo- sac, two cells called corpuscles, d, have made their appearance. Each of these is at first separated from the inner surface of the micropylar end of the sac by a single cell, which afterwards divides into four, leaving a passage from the surface of the sac down to the corpuscle. The pollen-grain, c, on the summit of the nucleus, then sends down a tube which perforates the embryo-sac, and reaches the corpuscle through the intercellular canal. 294 EMBRYOGENY IN GYMNOSPERMS. into the substance of the nucleus. The four elongated pro-embryonic cells (fig. 526, 1) now appear as isolated suspensors (fig. 526, 2), and the cell at the end of each suspensor becomes an embryo, g. There are thus four times as many rudimentary embryos as there are corpuscles. Usually one of these only becomes developed as the embryo of the ripe seed. Fig. 524, Fig. 526. Fig. 525, In many points this process resembles what takes place in Lyco- pods. The anthers of Gymnosperms may be considered as corresponding to the microsporangia, and the grains of pollen to the microspores. Certain cells in the anther may represent the prothallus, while a. cell forming the pollen-tube may be the antheridium. The embryo-sac in Gymnosperms may be reckoned equivalent to the macrospores, and the endospermal cellular development may be analogous to the pro- thallus produced in the large spore of Selaginella (see page 278). The prothallus in some Ferns, as Ophioglossacex, is produced inside the spore, while in others it grows out from it in the form of a green expansion, bearing both antheridia‘and archegonia (fig. 507, p. 280). Embryogenic process in Angiospermous Flowering Plants, In the case of Angiospermous Phanerogams, the pollen-grains (fig. 527 gp) are discharged from the anther, and are applied to the stigmatic surface of the pistil (fig. 527 ps), either directly or by the Fig. 524. Nucleated cells of what Hofmeister calls the pro-embryo, in the ovule of the Weymouth Pine (Pinus Strobus). The cells are pushed downwards into the cellular tissue of the nucleus by the elongation of the upper cells, which finally form the suspensor. Fig. 525. The same pro-embryonic body in the ovule of the Weymouth Pine, with the lower cells pushed farther down by the elongation of the upper suspensory cells. Fig. 526. Suspensors taken from the ovule of the Weymouth Pine (Pinus Strobus). In No, 1 the four suspensors are united. They form a cylinder composed of four elongated cells, and at the end, p, are seen some of the lower nucleated cells of the pro-embryo. In No. 2 the suspen- sors have separated, three of them, a, are cut off, and the remaining one, b, is connected with the embryo, g, at its extremity. EMBRYOGENY IN ANGIOSPERMS. 295 agency of wind or insects. The viscid fluid secreted by the stigmatic cells (ps) causes a rupture of the extine, and the intine passes out in the form of a tubular prolongation, which gradually elongates (tp, tp) as it proceeds down the loose conduct- ing tissue (tc, tc) of the style till it reaches the ovule. The length attained by the pollen-tube is sometimes very great. In Cereus grandiflorus, Morren estimated that the tubes, when they reached the ovary, extended as far as 1150 times the diameter of the pollen- grain ; in Crinum amabile, Hassall says that they reach 1875 times the diameter of the grain; in Cleome speciosa, 2719 times; in Oxyanthus speciosus, 4489. times; and in Colchicum autumnale, 9000 times. The length of time which the pollen-ttlbe takes to traverse the conducting tissues of the style in Angio- sperms varies. On reaching the ovule the pollen- tube enters the foramen, and finally comes into contact with the embryo-sac (fig. 528 ¢). In the interior of this sac one or more nucleated germ-vesicles are produced before impregna- tion in the midst of the endospermal cells and protoplasmic matter (fig. 530 ¢). In fig. 529 an anatropal ovule is represented with the raphe r, the opening in the primine and secundine ew, en, the nucleus n, the embryo-sac es, and the pollen-tube pi, in contact with the germ-vesicle ¢, 3 After the contact of the pollen-tube, one of the embryonal vesicles becomes enlarged, and is then divided by septa into two, the upper division growing out in a filamentous form, constituting the suspensor (fig. 530 s, 531 6), while the lower portion enlarges and divides re- peatedly so as to form a cellular globule—the embryo (fig. 530 s, 531 c). The parts of the embryo being finally differentiated into cotyledonary and radicular portions, as shown in fig. 532, 1-4. Taking a comprehensive view of the whole subject, it may be said that the union of two kinds of cells appears to be necessary for fertilisation, In‘ Cryptogamic plants this has been traced, particularly Fig. 527. Fig. 527. Portion of the stigma of Antirrhinum majus at the time of fecundation. ps, ps, Superficial cells forming the papille. tc, tc, Deep elongated cylindrical cells forming the conducting tissue. gp, Grains of pollen attached to the surface of the stigma, the extine having been ruptured, and the intine protruded in the form of tubes, tp, tp, which pierce the interstices between the superficial stigmatic cells. 296 EMBRYOGENY IN ANGIOSPERMS. in certain cases of conjugation ; where the two cells come into contact, a tube is formed between them, and the contents of the one unite Fig. 528. Fig. 530. Fig. 532. Fig. 531. Fig. 528. Section of ovule of an Orchis (Orchis Morio), showing the pollen-tube passing through the endostome, and reaching the embryo-sac in the nucleus. The closed and enlarged end of the tube, ¢, is applied to the sac, in which a germ-vesicle had been pre- viously formed. Transudation of fluids takes place, and the embryo, e, is developed at the lower end of the germinal or embryonal vesicle while the upper part of the vesicle elon- gates, and forms a confervoid suspensor. Fig. 529. Section of anatropal ovule. 1, Raphe, ch, -Chalaza. p, Primine. s, Secundine. ex, Exostome. en, Endostome. 1, Nucleus. es, Embryo-sac. pt, Pollen-tube. 9s, The germ-cell which forms the embryo. Fig 530. Section of the ovule of Ginothera, showing the pollen-tube, ¢, with its enlarged extremity applied to the end of the embryo-sac, and introverting it slightly ; one of the germinal vesicles in the sac has been impregnated, and has divided into two parts, the upper part forming a confervoid septate suspensor, s, and the lower dividing into four parts, which form a globular mass—the rudimentary embryo, surrounded by endospermal cells, e. Fig. 531. Ovule of Orchis mascula. a, Primine. 0, Secundine. ¢, Embryo. ¢, Confervoid filament which proceeds from the embryo towards the placenta. Fig. 582. The embryo in different stages of development. 1, Embryo in young state as a globular mass at the end of a suspensor, 2 and 3, Embryo more advanced. 4, Embryo showing the division into two cotyledons. PRODUCTION OF HYBRIDS. 297 with those of the other, giving rise to a germinating body. In Phanerogamic plants, also, there are two cells with different contents —the pollen-grain with its granular fovilla, and the ovule with its protoplasm, These are brought into connection by means of the pollen-tube, formed from the intine, which either enters the embryo- sac, or comes into contact with it, the union taking place either directly by its extremity, or indirectly by cellular prolongations from the conducting tissue, or from the ovule. By this means the formation of the embryo is determined, which commences as a cellular body or germinal vesicle, in the interior of which other cells are sub- sequently formed in a definite order of succession. THe Propuction or Hysrips.—lf the pollen of one species is employed to fertilise the ovules of another, the seed will often pro- duce plants intermediate between the two parents. These are termed hybrids, and are analogous to mules in the animal kingdom. Asa general rule, hybrids can only be produced between plants which are very nearly allied, as between the different species of the same genus. Thus, different species of Heath, Fuchsia, Cereus, Rhododendron, and Azalea, readily inoculate each other, and produce interme- diate forms, It is found, however, that many plants which seem to be nearly related do not hybridise, Thus, hybrids are not met with between the Apple and the Pear, between the Gooseberry and Currant, nor between the Raspberry and Strawberry. The ovules of Fuchsia coccinea, fertilised with the pollen of Fuchsia fulgens, pro- duce ‘plants having intermediate forms between these two species, Some of the seedling plants closely resemble the one parent, and some the other, but they all partake more or less of the characters of each. By the examination of the foliage, conclusions may be drawn as to what will be the character of the flower. Mr. Thwaites men- tions a case in which a seed produced two plants extremely different in appearance and character, one partaking rather of .the character of Fuchsia fulgens, and the other of Fuchsia coccinea. While hybrids are produced between two species, crosses are produced between two varieties. ‘ In the case of hybridisation, there appears to be a mixture of matters derived from the ‘pollen-grain and the ovule, just like the mixture of two endochromes in flowerless plants; and the nature of the hybrid depends on the preponderance of the one or other. Some have supposed that the pollen-grains require to be of the same form and dimensions in order to admit of artificial union taking place ; but this is a mere conjecture. It is, however, requisite for successful hybridising, that the pollen should be in a state of full maturity, and the stigma perfect. Hybrids perform the same functions as their parents, but they do not perpetuate themselves by seed. They must be propagated by offsets or cuttings. If not absolutely sterile at first, 298 FRUIT OR MATURE PISTIL. they usually become so in the course of the second or third generation. Herbert mentions instances of hybrid Narcissi, from which he at- tempted in vain to obtain seed. The cause of this sterility has not been determined. Some have referred it to an alteration in the pollen. Hybrids may be fertilised, however, by the pollen taken from one of the parents, and then the offspring assumes more or less the characters of that parent. Hybrids are rarely produced naturally, as the stigma is more likely to be affected by the pollen of plants of its own species than by that of other species. In dicecious plants, however, this is not the case, and hence the reason, probably, of the numerous co-called species of Willows. Hybrids are constantly produced artificially, with the view of obtaining choice flowers and fruits, the plants being propagated afterwards by cuttings. In this way many beautiful Roses, Azaleas, Rhododendrons, Pansies, Cactuses, Pelargoniums, Fuchsias, Calceo- larias, Narcissuses, etc., have been obtained. By this process of inoculation, and carefully selecting the parents, gardeners are enabled to increase the size of the flowers, to improve their colour, to render tender plants hardy, and to heighten the flavour of fruits. Herbert thinks, from what he saw in Amaryllides, that in hybrids the flowers and organs of reproduction partake of the characters of the female parent, while the foliage and habit, or the organs of vegetation, re- semble the male. 6.—Fruit, or the Pistil arrived at Maturity. After fertilisation, various changes take place in the parts of the flower. Those more immediately concerned in the process, the anther and stigma, rapidly wither and decay, while the filaments and style often remain for some time ; the floral envelopes also become dry, the petals fall, and the sepals are either deciduous, or remain persistent in an altered form; the ovary becomes enlarged, forming the pericarp (aegé, around, and xaerés, fruit); and the ovules are developed as the seeds containing the embryo-plant. The term fruit is strictly applied to the mature pistil or ovary, with the seeds in its interior. But it often includes other parts of the flower, such as the bracts and floral envelopes. Thus, the fruit of the Hazel and Oak consists of the ovary and bracts and calyx combined ; that of the Apple, Pear, and Gooseberry, of the ovary and calyx; and that of the Pine-apple, of the ovaries and floral envelopes of several flowers combined. Fruits formed by the ovaries alone, as the Plum and the Grape, seem to be more liable to drop off and suffer from unfavourable weather, than those which have the calyx attached, as the Gooseberry, the Melon, and the Apple. In general, the fruit is not ripened unless fertilisation has been FRUIT OR MATURE PISTIL. 299 effected ; but cases occur in which the fruit swells, and becomes to all appearance perfect, while no seeds are produced. Thus, there are seedless Oranges, Grapes, and Pine-Apples. When the seeds are abortive, it is common to see the fruit wither and not come to maturity ; but in the case of Bananas, Plantains, and Bread-fruit, the non-development of seeds seems to lead to a larger growth and a greater succulence of fruit. In order to comprehend the structure of the fruit, it is of great importance to study that of the ovary in the young state. It is in this -way only that the changes occurring in the progress of growth can be determined. The fruit, like the ovary, may be formed of a single -earpel, or of several. It may have one cell or cavity, then being uni- ‘locular (wnus, one, and loculus, box or cavity) ; or many, multilocular (multus, many), etc. The number and nature of the divisions depend on the number of carpels, and the extent to which their edges are ‘folded inwards, The appearances presented by the ovary do not, however, always remain permanent in the fruit. Great changes are observed to take place, not merely as regards the increased size of the ovary, its softening and hardening, but also in its internal structure, owing to the suppression, enlargement, or union of parts. In this way the parts of the fruit often become unsymmetri- eal, that is, not equal to, or not a multiple of, the parts of the flower; and at times they are developed more in one ‘direction than another, so as to assume an irregular appear- ance. In the Ash (fig. 533) an ovary with two cells, each containing an ovule attached to a central placenta, is changed into a unilocular fruit with one seed; one ovule, J, having become abortive, and the other, g, gradually ex- tending until the septum is pushed to one side, ‘becoming united to the walls of the cell, and the placenta appearing to be parietal. In the Oak and Hazel, an ovary with three cells, and two ovules in each, changes into a one-celled fruit with one seed. Similar changes take place in the Horse-chestnut, in which the remains of the abor- tive ovules are often seen in the ripe fruit. In the Coco-nut, a trilocular and triovular ovary is changed into a one-celled, one-seeded fruit. This abortion may depend on the pressure caused by the development of certain ovules, or it may proceed from the influence of the pollen not being communicated to all the ovules. Again, by the growth of the placenta or the folding inwards of parts Fig. 533. Fig. 533. Samara or Samaroid fruit of Fraxinus oxyphylla. 1, Entire, with its wing, u. 2, Lower portion cut transversely, to show that it consists of two loculaments; one of which, 1, is abortive, and is reduced to a very small cavity, while the other is much enlarged, and filled with a seed, g. i 300 FRUIT OR MATURE PISTIL. of the ovary, divisions may take place in the fruit which did not exist in the ovary. In Pretrea zanzibarica a one-celled ovary is changed into a four-celled fruit by the extension of the placenta. In Cathartocarpus Fistula (fig. 429, p. 244) a one-celled ovary is changed into a fruit having each of its seeds in a separate cell, in con- sequence of spurious dissepiments being pro- duced in a horizontal manner, from the inner wall of the ovary after fertilisation, In Tri- bulus terrestris, each cell of the ovary (fig. 534) has slight projections, ¢, on its walls, in- terposed between the ovules, 0, which, when the fruit is ripe, are seen to have formed dis- tinct transverse divisions (fig. 535 c), or spurious dissepiments, separating the seeds, g. In Astragalus, the folding of the dorsal suture inwards converts a one- celled ovary into a two-celled fruit ; and in Oxytropis the folding of the ventral suture gives rise to a similar change in the fruit. The development of cellular or pulpy matter frequently alters the appearance of the fruit, and renders it difficult to discover its formation, In the Strawberry, the axis becomes succulent, and bears the carpels on its convex surface; in the Rose there is a fleshy hollow torus or disk, which bears the carpels on its concave surface. In the Goose- berry, Grape, Guava, Tomato, and Pomegranate, the seeds nestle in pulp formed apparently by the placentas. In the Orange, the pulpy matter surrounding the seeds is formed by succulent cells, which are produced from the inner partitioned lining of the pericarp. The pistil, in its simplest state, consists of a carpel or folded leaf, with ovules at its margin; and the same thing will be found in the fruit, where the pericarp, as in the Bean (fig. 536), represents the carpellary leaf, and the seeds correspond to the ovules. The pericarp consists usually of three layers; the external (fig. 536 ¢), or epicarp éri, upon, or on the outside, xaerés, fruit), corresponding to the lower epidermis of the leaf; the middle (fig. 536 m), or mesocarp (uéoos, middle), representing the parenchyma of the leaf; and the internal (fig. 536 1), or endocarp (évdov, within), equivalent to the upper epidermis of the leaf, or the epithelium of the ovary. In some plants, as Bladder Senna (Colutea arborescens), the pericarp retains its leaf- like appearance, but in most cases it becomes altered both in con- sistence and in colour. Sometimes the three parts become blended together, as in the Nut; at other times, as in the Peach, they remain separable, In the latter fruit, the epicarp is thickened by the addition Fig. 534. Fig. 535. Fig. 534, Cell or loculament of the ovary of Tribulus terrestris, cut vertically, to show the commencement of the projections, c, from the paries, which are interposed between the ovules, 0. Fig. 535. The same in a mature state, showing the transverse partitions, e, dividing the fruit into cavities, in one of which aseed, g, is left. t FRUIT OR MATURE PISTIL. 301 of cells, and can be taken off in the form of what is called the skin . the mesocarp becomes much developed, forming the flesh or pulp, and hence has sometimes been called surcocarp (otgé, flesh), while the endocarp becomes hardened by the production of woody cells, and forms the stone or putamen (putamen, a shell), immediately covering the kernel or the seed. The same arrangement is seen in the fruit of the Cherry, Apricot, and Plum. In these cases, the meso- carp is the part of the fruit which is eaten. In the Almond, on the other hand, the seed is used as food, while the shell or endocarp, with its leathery covering or mesocarp, and its greenish epicarp, are rejected. The pulpy matter found in the interior of fruits, such as the Gooseberry, Grape, and Cathartocarpus Fistula (fig. 429, p. 244), is formed from the placentas, and must not be confounded with the sarcocarp. In the Date the epicarp is the outer brownish skin, the pulpy matter is the mesocarp or sarcocarp, and the thin papery-like lining is the endocarp covering the hard seed. In the Pear and Apple the outer skin or epicarp is the epidermal covering ; the fleshy portion is the mesocarp, formed by the cellular torus; while the scaly layer, forming the walls of the seed-bearing cavities in the centre, is the endocarp. In the Medlar (fig. 568, p. 314) the endocarp becomes of a stony hardness. In the Melon the epicarp and endocarp are very thin, while the mesocarp forms the bulk of the fruit, varying in its texture and taste in the external and internal part. The rind of the Orange consists of epicarp and mesocarp, while the endocarp forms partitions in the interior, filled with pulpy cells. While normally the divisions of the fruit ought to indicate the number of the carpels composing it, and these carpels should each have three layers forming the walls, it is found that frequently the divisions of a multilocular fruit are atrophied or absorbed, in whole or in part, and the layers become confounded together, so that they appear to be one. Again, in fruits formed of several carpels, the endocarp and mesocarp are occasionally so much developed as to leave the epicarp only on the free dorsal face of the fruit, forming a covering which is wholly external, as in the Castor-oil plant (fig. 543, p. 304), Euphorbia, and Mallow (fig. 548, p. 305). Occasionally, the endo- carp remains attached to the centre, forming cells, in which the seeds are placed, while the outer layer separates from it at certain ° Fig. 536, Lower portion of the carpel or legume of the Bean, Faba sativa, cut trans- versely, to show the structure of the pericarp. ¢, Epicarp, or external epidermis. m, Mesocarp. n, Endocarp. sd, Dorsal suture. sv, Ventral suture. g, A seed situated at the upper part of the section, and cut also transversely. 302 FRUIT OR MATURE PISTIL. points, and leaves a row of cavities in the substance of the pericarp itself. In some fruits the calyx is superior, or in other words above the pericarp, while in others it is closely applied to the ovary, but separable from it. Thus in the fruit of Mirabilis Jalapa (fig. 537, 1), when a section is made longitudinally (fig. 537, 2), the hardened calyx (perianth), cc, is distinct from the fruit, j, which is in this instance incorporated with the seed, but at once distinguished by its style, s. The same thing occurs in Spinach (Spinacia). Again, in the Yew (fig. 538), there is an external succulent covering, ‘%c, formed by modified bracts, which here occupy the place of a pericarp, and surround the seed, g, which is naked, inasmuch as it is not con- tained in a true ovary with a stigma. Fig. 537, 1. Fig. 537, 2. The part of the pericarp attached to the peduncle is called its base, and the part where the style or stigma existed is the apex. This latter is not always the mathematical apex. In Alchemilla, Fragaria, Labiatze, and Boraginacez, it is at the base or side (figs. 434, 435, 436, pp. 246, 247). Thestyle sometimes remains in a hardened form, rendering the fruit apiculate; at other times it falls off, leaving only traces of its existence. The presence of the style or stigma serves to distinguish certain single-seeded pericarps from seeds. As in the case of the carpel, so in the mature ovary formed of it, the edges unite towards the axis, and constitute the ventral suture (fig. 539 sv), while the back, corresponding with the midrib, is the dorsal suture (fig. 539 sd). The inner suture in some fruits formed of a single carpel, as the Apricot and Bladder Senna, is marked by a distinct furrow or depression, consequent on the folding inwards of the carpellary edges ; and occasionally the outer or dorsal suture is also Fig. 537. Fruit of Mirabilis Jalapa. 1, Entire. 2, Cut longitudinally, to show its com- position. cc, Lower part of perianth hardened, and forming an outer envelope. /, The true fruit, covered by the perianth. The integuments of the fruit are incorporated with those of the seed, which has been also cut. The fruit is distinguished by the remains of the style, s, at the apiculus or summit. Fig. 538. Fruit of Taxus baccata, the Yew. 0b, Imbricated bracts at its base. ic, Fleshy envelope taking the place of the pericarp. This envelope eovers the seed, g, partially, leaving its apex naked. INDEHISCENT AND DEHISCENT FRUITS. 303 thus rendered distinctly visible. When the fruit consists of several mature carpels, all meeting in the centre, and united together, then the dorsal suture is also visible ex- ternally ; but in cases where the placentation is either parietal or free central, the edges of the sepa- tate carpels, being near the surface, may present also externally the marks of the ventral sutures. Where the sutures are formed, there are usually two bundles of fibro-vascular tissue (fig. 539), one on each edge. The edges of the sutures are often so intimately united as not to give way when the fruit is ripe. In this case it is called indehiscent (in, used in the sense of not, and dehtsco, I open), as in the Acorn and Nut ; at other times the fruit opens between the two vascular bundles, either at the ventral or dorsal suture, or at both, so as to allow the seeds to escape, and then it is dehiscent (dehisco, I open). By this dehiscence the pericarp becomes divided into different pieces, which are denominated valves, the fruit being univalvular, bivalvular, or multi- valvular, etc., according as there are one, two, or many valves. These valves separate either completely or par- tially. In the latter case, the divisions may open in the form of teeth at the apex of the fruit, the dehiscence being apicilar, as in Caryophyllaces (fig. 540 v), or as partial slits of the ventral suture, when the carpels are g.540. only free at the apex, as in Saxifrages, InpEHIScENT Fruits are either dry, as the Nut, or fleshy, as the Cherry and Apple. They may be formed of one or several carpels ; and in the former case they usually contain only a single seed, which may become so incorporated with the pericarp as to appear to be naked. Such fruits are called pseudospermous (evdqs, false, and owtgwa, seed), or false-seeded, and are well seen in the grain of Wheat. In such cases the presence of the style or stigma determines their true nature. Dzntscent Fruirs, when composed of single carpels, may open by the ventral suture only, as in the follicles of Peony, Hellebore (fig. 539), and Calthea ; by the dorsal suture only, as in Magnolias and some Proteaces ; or by both together, as in the legume of the Pea and Bean; in which cases the dehiscence is called sutural. When composed of several united carpels, the valves may separate through Fig. 539, Fig. 589. A single carpel of Helleborus foetidus after dehiscence. sd, Dorsal suture. sv, Ventral suture. The carpel, when mature, opens on the ventral suture, and forms the fruit denominated a follicle. Fig. 540. Capsule or dry seed-vessel of Cerastium triviale after dehiscence. c, Persistent calyx. p, Pericarp dividing at the apex, v, into ten teeth, which indicate the summits of as many valves united below. 304 DEHISCENT FRUITS. the dissepiments, so that the fruit will be resolved into its original carpels, as in Rhododendron, Colchicum, etc. This dehiscence, in consequence of taking place through the lamell of the septum, is called septicidal (septum and ceedo, I cut) (figs. 541, 542). The valves Fig. 544. Fig. 545. Fig. 546, may separate from their commissure, or central line of union, carrying the placentas with them, or they may leave the latter in the centre, so as to form with the axis a column of a cylindrical, conical, or prismatic shape, which has received the designation of colwmella (fig. Fig. 541. Capsule of Digitalis purpurea at the moment of dehiscence, when the two cavities, cc, separate by division of the septum, dd, so as to have'the appearance of distinct earpels. At the apex are seen the seeds, g. Fig. 542, Inferior portion of the same cap- sule cut transversely, to show the formation of the septum, formed by the two inner faces of the carpels,cc. pp, Placentaries reflected and projecting into the interior of the cavities. g, Seeds. Fig. 543. Capsule (tricoccous regma) of Ricinus communis, Castor-oil plant, at the moment of dehiscence. The three carpels or cocci, ¢.cc, are separated from the axis, a, by which they were at first united (see fig. 549), and which remains in a colum- nar-form. These cocci begin to open by their dorsal suture, sd. Fig. 544, Capsule of Iris opening by loculicidal dehiscence. Fig. 545. Capsule of Hibiscus esculentus, show- ing loculicidal dehiscence. vv v, Valves of the seed-vessel. c, Septum or partition. g, Seeds, Fig. 546. Capsule of Cedrela angustifolia, the valves of which, v v v, separate from the septa, c c, by septifragal dehiscence. The separation takes place from above down- wards, in such a manner that the axis, a, remains in the centre, with five projecting angles, corresponding to the septa. g, The seeds contained in the loculaments. DEHISCENT FRUITS. 305 543 c), The union between the edges of the carpels may be persistent, and they may dehisce by the dorsal suture, or through the back of the loculaments, as in the Lily and Iris (fig. 544). In’ this case the valves are formed by the halves of the cells, and the septa either remain united to the axis, or they separate from it, carrying the placentas with them (fig. 545), or leaving them in the centre. This dehiscence is loculicidal (loculus, cell, and cdo, I cut). Sometimes the fruit opens by the dorsal suture, and at the same time the valves or walls of the ovaries separate from the septa (fig. 546), leaving them attached to the centre, as in Thorn Apple (Datura Stramonium). This is called septifragal dehiscence (septum and frango, I break), and may be looked upon as a modification of the loculicidal. The separation of the valves takes place either from above downwards (fig. 546), or from below upwards (fig. 547). Sometimes the axis is prolonged as far as the base of the styles, as in the Mallow (figs. 548; 417, p. 239), and Castor-oil plant (fig. 549), | IIE ay i iy a Fig. 547. : Fig. 549. the carpels being united to it by their faces, and separating from it without opening. In the Umbelliferee (fig. 550) the two carpels separate from the lower part of the axis, and remain attached to a prolongation of it, called a carpophore (xagrés, fruit, and gogéw, I bear), or ~podocarp (obs, foot, and xaerds, fruit), which splits into two (fig. 550 a), and suspends them. Hence the name cremocarp (xecucu, Fig. 547. Capsule of Swietenia Mahagoni, opening by valves from below upwards. The letters have the same signification as in fig. 546. Fig. 548, Fruit of Malva rotundifolia, with half the carpels composing it removed, to show the axis, a, to which they are attached. This axis ends at the point where the style, s, is produced. ec, The carpels, which are left attached to the axis, around which they are arranged in a verticillate’manner. The lateral surface of the two carpels in front, c’, is exposed. Fig. 549. Tricoccous capsule of Rici- nus communis, Castor-oil plant, cut vertically, to show the axis, a, prolonged between the carpels, and terminating by small cords or funiculi, f, which project into the loculaments, and are attached to seeds. gg, Seeds exposed, each surmounted by a fleshy caruncula, c. p, Pericarp. x 306 ’ DEHISCENT FRUITS. I suspend or hang), applied to this fruit. By some authors the term schizocarp (oxifw, 1 split) is applied to such dry fruits consisting of one or more; one-seeded or few-seeded, indehiscent carpels. In Geraniacee the axis is prolonged beyond the carpels, forming a carpophore, to which the styles are attached, and the pericarps separate from below upwards, before dehiscing by their ventral suture (fig. 551). Carpels of this kind are called cocci (x6xxos, kernel), and the fruit is said to be tricoc- cous, etc., according to the number of separate carpels. In the case of many Euphorbiacez, as Fig. 550. Hura crepitans, the cocci separate with great force and elasticity, the cells being called dissilient (dissilio, I burst asunder). In the Siliqua, or fruit of. Cruciferae, as Wallflower (fig. 552), the valves separate from the base of the fruit, leaving a central replum, or Fig, 551. Fig, 552. frame, r. The replum is considered as being formed by parietal placentas, which remain attached to the fibro-vascular line of the suture, the valves giving way on either side of the suture. In Orchi- daceze (fig. 553) the pericarp, when ripe, separates into three valves, Fig. 550. Fruit or cremocarp of Prangos uloptera, an umbelliferous plant. Fruit some- times called schizocarp. The carpels, mericarps, or acheenia, cc, separate from the axis, a, and are each suspended by a carpophore. ss, Persistent styles with swollen bases, formed by an epigynous disk. Fig. 551. Fruit or mature carpel of Geranium sanguineum. ¢, Persis- tent calyx. a, Axis prolonged as a beak. ¢ ¢, the styles at first united to the beak, and afterwards separating from below upwards, along with the earpels, o 0, which dehisce by their ventral suture. s, Stigmas. The fruit is sometimes called gynobasic. Fig. 652. Siliqua of Cheiranthus Cheiri, Wallflower, dehiscing by two valves, v v, which separate from aframe orreplum,r. g, Seeds arranged on either margin. s, Two-lobed stigma. Fig. 553. Capsule of Orchis maculata at the period of dehiscence. c, Remains of the perianth crowning the fruit. vv, Segments of the pericarp which are detached in the form of valves. p, Arched repla or placentas which remain persistent, and bear the seeds. DEHISCENT FRUITS. 807 by giving way only on the margins within the sutures, where the placentas are united ; and when the valves fall off, the placentas are left in the form of three arched repla, or frames, to which the seeds are attached. In the case of a free central placenta, when the valves separate, it is sometimes difficult to tell whether the dehiscence is septicidal or loculicidal, inas- much as there are no dissepi- ments, and the placentas and seeds form a column in the axis. Their number, as well as their alternation or opposition, as compared with the sepals, will aid in determining whether the valves are.the entire carpellary leaves, as in septicidal dehis- cence, or only halves united, as in loculicidal dehiscence. In some instances, as in Linum catharticum, the fruit opens first by loculicidal dehiscence, and afterwards the carpels separate in a septicidal manner. Another mode in which fruits open is transversely, the dehiscence in this case being called circumscissile (circwm, around, and scindo, I cut). In such cases, the fruit or seed-vessel may be supposed to be formed by a number of articulated leaves like those of the Orange, the division taking place where the laminz join the petioles. In this dehiscence the upper part of the united valves falls off in the form of a lid or operculum, as in Anagallis (fig. 554), and in Henbane (Hyo- scyamus), (fig. 555), and hence the fruit is often denominated operculate (operculum, a lid). In some instances the axis seems to be prolonged in the form of a hollow cup, and the valves appear as leaves united to ‘it by articulation, similar to what occurs in the calyx of Eschscholtzia. In Lecythis (the Monkey-pot) and in Couratari the calyx is superior, and the lid is formed at the place where the calyx is attached. Transverse divisions take place occasionally in fruits formed by a single carpel, as in the pods of some leguminous plants. Examples Fig. 554. Pyxidium or capsule of Anagallis arvensis, opening by circumscissile dehis- cence, ¢, Persistent calyx. sp, Pericarp divided into two, the upper part, 0, separating in the form of a lid or operculum. On the capsule are seen three lines passing from the base to the apex, and marking the true valves. g, Seeds forming a globular mass round a central placenta, Fig. 555. Operculate capsule or pyxidium of Hyoscyamus niger, Henbane. o, Operculum or lid separating and allowing the seeds to appear. Fig. 556. Lomentaceous legume or lomentum (transverse schizocarp) of Hedysarum coronarium. 1, Entire, the upper division being nearly detached from the rest. 2, Two of the joints cut longitudinally to show the spurious loculaments, each containing a seed. This seed-vessel divides into separate single-seeded portions by solubility. 308 CARPOLOGY. are seen in Ornithopus, Hedysarum (fig. 556), Entada, Coronilla, and the Gum-arabic plant (Acacia arabica), in which each seed is con- tained in a separate division, the partitions being formed by the folding in of the sides of the pericarp, and distinct separations taking place at these partitions by what has been termed solubility. The name schizocarp has been also applied to such fruits. In Cathartocarpus Fistula transverse partitions occur without exhibit- ing evident separations of the parts externally. Some look upon these pods as formed by pinnate leaves folded, and the divisions ' as indicating the points where the different pairs of pinne are united. Dehiscence may also be effected by partial openings in the pericarp, called pores, which are situated either at the apex, base, or side. In the Poppy (fig. 444, p. 249) the opening takes place by numerous pores under the peltate processes bearing the stigmas, In Campanulas there are irregular openings towards the middle or base (fig. 557 t), which pierce the pericarp. In Frogsmouth or Snapdragon (fig. 558) the pericarp gives way at certain fixed points, forming two or three orifices, one of which corresponds to the upper carpel, and the other to Fig. 557. Fig. 558. the lower. These orifices have a ragged appearance at the margins, which has given rise to the name rupturing, as applied to this mode of dehiscence. CarpoLocy.—Much has been done of late in the study of car- pology (xagarés, fruit, and Aéyos, discourse), or the formation of the fruit ; but much still remains to be done ere the terminology of this department is complete. Many classifications of fruits have been given, but they are confessedly imperfect, and unfortunately much confusion has arisen in consequence of the same names having been applied to different kinds of fruit. In many cases, therefore, it is necessary to give a description of a fruit in place of using any single term. There are, however, some names in general use, and others which have been carefully defined, to which it is necessary to direct attention, Fruits may be formed by one flower, or they may be the pro- Fig. 557. Capsule of Campanula persicifolia, opening by holes or pores, tt, above the middle. c, Persistent calyx, separating above the pericarp, p, into five acute segments, in the midst of which is seen the withered and plaited corolla, in the form of induvie, v. The holes perforate the walls of the pericarp. Fig. 558. Capsule of Antirrhinum majus, Frogs- mouth, after dehiscence. cc, Persistent calyx. , Pericarp perforated near the summit by three holes, ¢ t, two of which correspond to one of the loculaments, and one to the other. The apex of the capsule is acuminated by the remains of the persistent style, ». INDEHISCENT APOCARPOUS FRUITS. 309 duct of several flowers combined. In the former case they are either apocarpous (dro, separate, and xaerés, fruit), or dialycarpous (deAtw, I part asunder), that is, composed of one mature carpel, or of several separate free carpels ; or syncarpous (odv, together), that is, composed of several carpels, more or less completely united. These different kinds of fruits may be indehiscent (not opening), or dehiscent (opening). When the fruit is composed of the ovaries of several flowers united, it is usual to find the bracts and floral envelopes also joined with them, so as'to form one mass; hence such fruits are called multiple or anthocarpous (évbos, flower, and xaerés, fruit). The term simple is perhaps properly applied to fruits which are formed by the ovary of a single flower, whether they are composed of one or several carpels, and whether these carpels are separate or combined. Simple fruits are hence sometimes denominated Monogynecial (uévos, one, yuv7, pistil, and o/xsov, habitation), as being formed by one gyne- cium ; while multiple fruits are called polygynecial (woAds, many) as being formed by many gyneecia. Simple or Monogynecial Fruits which are the produce of a Single Flower, Apocarpous Fruits.— These fruits are formed out of one or several free carpels. They are either dry or succulent; the pericarp, in the former instance, remaining more or less feliaceous in its struc- ture, and sometimes becoming incorporated with the seed; in the latter, becoming thick and fleshy, or pulpy. Some of these do not open when ripe, but fall entire, the pericarp either decaying, and thus allowing the seeds ultimately to escape, as is common in fleshy fruits, or remaining united to the seed, and being ruptured irregularly when the young plant begins to grow; such fruits are indehiscent. Other apocarpous fruits, when mature, open spontaneously to discharge the seeds, and are dehiscent. : InpEniscent ApocaRpous Fruits, when formed of a single mature carpel, frequently contain only one seed, being thus monospermous (wdvos, one, and oréeua, seed). In some instances there may have: been only one ovule originally, in others two, one of which has become abortive. The Achenium (a, privative, and xaivw, I open) is a dry monospermous fruit, the pericarp of which is closely applied to the Fig., 559. Fig. 559. Achznium or indehiscent monospermous carpel from the pistil of a Ranunculus. Fig. 560. 1, Similar achenium, with rough points on the pericarp, from the pistil of Ranun- culus muricatus. 2, Achenium cut transversely to show the seed, g, not adherent to the parietes, 310 INDEHISCENT APOCARPOUS FRUITS. seed, but separable from it (fig. 559). It may be solitary, forming a single fruit, as in the Cashew (fig. 248 a, p. 173), where it is supported on a fleshy peduncle, p ; or aggregate, as in Rununculus (fig. 560), where several acheenia are placed on a common elevated receptacle. In the Strawberry the achenia (fig. 434, p. 246) are placed on a convex succulent receptacle. In the Rose they are supported on a concave receptacle (fig. 294, p. 196), and in the Fig they are placed inside the hollow peduncle or receptacle (fig. 267, p. 180), which ultimately forms what is commonly called the fruit. In Dorstenia (fig. 266, p. 180) the achenes are situated on a flat or slightly concave receptacle. In the Rose the aggregate achenia, with their covering, are sometimes collectively called Cynarrhodum (xtwv, a dog, and édov, a rose, seen in the dog-rose). It will thus be remarked that what in common language are called the seeds of the Strawberry, Rose, and Fig, are in reality carpels, which, are distinguished from seeds by the presence of styles and stigmas. The styles occasionally remain attached to the achenia, in the form of feathery appendages, as in Clematis, where they are called caudate (cauda, a tail). In Composite the fruit, which is sometimes called Cypsela (avpéan, a box), when ripe, is an achzenium (fig. 301 t, p. 199). The calyx in the Fig. 561. Fig. 562. Fig. 568. Composites sometimes becomes pappose, and remains attached to the fruit (fig. 303, p. 199), as in Dandelion and Thistles. A pappose calyx occurs also in some Dipsacaces (fig. 302, p. 199). When the pericarp is thin, and appears like a bladder surrounding the seed, the acheenium becomes a Utricle, as in Amarantacese, This name is often Fig. 561. Seed-vessel of Acer Pseudo-platanus (Sycamore, called in Scotland Plane), com- posed of two samaras or winged monospermous carpels united. a, Upper part forming a dorsal wing. 1, Lower portion corresponding to the loculaments. Fig. 562. Samara taken from the fruit of Hivaa, s, Persistent style. 1, Part corresponding to the locula- ment. aa, Marginal wing orala. Fig. 563. Caryopsis of Secale cereale, Rye. 1, Entire. 2, Cut transversely to show the seed adherent to the parietes of the pericarp. INDEHISCENT APOCARPOUS FRUITS. 311 given to fruits which differ from the acheenium in being composed of more than one carpel. When the pericarp is extended in the form of a winged appendage, a samara (samera, seed of Elm) or samaroid achenium is produced, as in the Ash (fig: 533, p. 299), common Sycamore (fig. 561), and Hirea (fig. 562). In these cases there are usually two achenia united, one of which, however, as in Fraxinus oxyphylla (fig. 533), may be abortive. The Wing (fig. 561 a) is formed by the carpel, and is either dorsal, i.e. a prolongation from the median vein (fig. 561 a), or marginal, that is, formed by the lateral veins (fig. 562 a). It surrounds the fruit longitudinally in the Elm. When the pericarp becomes so incorporated with the seed as to be inseparable from it, as in grains of Wheat, Maize, Rye ‘(fig. 563), and other grasses, then the name caryopsis (xdgvoy, a nut, and o\vs, appearance) is given. There are some fruits which consist of two or more acheenia, at first united together, but which separate when ripe. Of this nature is the fruit of the Tropzolum or Indian Cress, also that of Labiate and Boraginacee, which is formed of four achznia attached to the axis (fig. 436, p. 247), whence the common style appears to proceed. Some of these are occasionally abortive. In the ripe state the pericarp separates from the seed in these cases; and thus there is a transition from indehiscent acheenia to single-seeded dehiscent peri- carps. The cremocarp (xgewcdw, I hang), or the fruit of Umbel- liferee (fig. 550, p. 306), is composed of two acheenia united by a com- missure to a common axis or carpophore (xaerés, fruit, and Qogéw, I bear), from which they are suspended at maturity. It is sometimes denominated diachenium (6/s, twice), from the union of two acheenia, which in this instance receive the name of mericarps (égoc, part), or hemicarps (7mious, half, and xweqés, fruit). The Nut or Glans.—This is a one-celled fruit with a hardened pericarp, surrounded by bracts at the base, and, when mature, con- taining only one seed. In the young state the ovary contains two or more ovules, but only one comes to maturity. It is illustrated by the fruit of the Hazel and Chestnut, which are covered by leafy appendages, in the form of a husk, and by the Acorn, in which the leaves or bracts are united so as to form a cupula or cup (fig. 281, p. 191). The parts of the pericarp of the Nut are united so as to appear one. In Sagus, or the Sago Palm, the nut is covered by peculiar tesselated epicarp, giving the appearance of a cone. The Drupe (drupe, unripe olives)—This is a succulent fruit covered by a pericarp, consisting of epicarp, mesocarp, and endocarp ; and when mature containing a single seed. This term is applied to such fruits as the Cherry, Peach, Plum, Apricot, Mango, Walnut, Nutmeg, and Date. The endocarp is usually hard, forming the stone of the fruit, which encloses the kernel or seed, The mesocarp is 312 DEHISCENT APOCARPOUS FRUITS. generally pulpy and succulent, so as to be truly a sarcocarp (ode, flesh), as in the Peach, but it is sometimes of a tough texture, as in the Almond, and at other times more or less fibrous. There is thus a transition from the Drupe to the Nut. Moreover, in the Almond, there are often two ovules formed, only one of which comes to per- fection. In the Walnut, the endocarp, which is easily separable into two, forms prolongations which enter into the interior, and cause the brain-like divisions in the seed. It has been sometimes called Tryma. In the Raspberry and Bramble several drupes or drupels are aggre- gated so as to constitute an Eterio (erajgos, acompanion). This name is also given by some to the aggregate achenes of the Strawberry and Rose. Deuiscent Apocarpous Fruits.—These open in various ways, and usually contain more than one seed, being either few-seeded, oligospermous (6Atyos, few, and oxégua, a seed), or many-seeded, poly- spermous (woAus, many). Follicle (folliculus, a fittle bag).—This is a mature car- pel, containing several seeds, and opening by the ventral suture (figs. 539, p. 303; 564). It is rare to meet with a solitary follicle forming the fruit. There are usually several aggregated together, either in a circular manner on a short- ened receptacle, as in Hellebore, Aconite, Delphinium, Crassulacee (fig. 282, p. 191), Butomus (fig. 415, p. 238), and Asclepiadacee ; or in a spiral manner on an elongated receptacle, as in Magnolias, Banksias, and Liriodendron (fig. Fig. 664. 337, p, 213). Occasionally, some of the follicles open by the dorsal suture, as in Magnolia grandifiora and Banksia. The Legume or Pod (legumen, pulse) is a solitary, simple, mature carpel, dehiscing by the ventral and dorsal suture, and bearing seeds on the former. It characterises leguminous plants, and is seen in the Bean and Pea (fig. 565). In the Bladder-senna (fig. 566) it retains its leaf-like appearance, and forms an inflated legume. In some Leguminose, as Arachis and Cathartocarpus Fistula (fig. 429, p. 244), and the Tamarind, the fruit must be considered a legume, although it does not dehisce. The first of these plants produces its fruit under- ground, and is called earth-nut ; the second has a partitioned legume ; and both the second and third have pulpy matter surrounding the seeds. In place of opening at the sutures, some legumes are contracted at intervals so as to include each seed in a separate cell, and when ripe, the different divisions of the pod separate from each other. This constitutes the Lomentwm (lomentum, bean-meal) or lomentaceous legume of Hedysarum coronarium (fig. 556, p. 307), Coronillas, Ornithopus, Entada, and some Acacias. In Medicago the legume is twisted like a snail (fig. 567), and in Cesalpinia coriaria, or Divi-divi, it is ver- Fig. 564. Follicle or dehiscent many-seeded carpel of Aquilegia vulgaris, Columbine. The follicle dehisces by the ventral suture only. * INDEHISCENT SYNCARPOUS FRUITS. 313 miform or curved like a worm ; in Carmichaelia the valves give way close to the suture, and separate from it, leaving a division. Fig. 565. Fig. 566, Fig. 567. Syncarpous Fruits are formed by several carpels, which are so united together as to appear one in their mature state. These fruits are either dry or succulent ; in the former case being usually dehiscent, in the latter indehiscent. InpEHIscEeNT SyncaRPous Fruits.—The Berry (bacca) is a succu- lent fruit, in which the seeds are immersed in a pulpy mass, formed by the placentas. The name is usually given to such fruits as the Gooseberry and Currant, in which the ovary is inferior, and the placentas are parietal, the seeds being ultimately detached from the placenta, and lying loose in the pulp. Others have applied it also to those in which the ovary is superior, as in the Grape, Potato, and Ardisia, and the placentas are central or free central. The latter might be separated under the name Uva (grape). In general, the name of baccate or berried is applied to all pulpy fruits: In the Pome- granate there is a peculiar baccate many-celled inferior fruit, having a tough rind, enclosing two rows of carpels placed above Fig. 565. Legume of Pisum sativum, common Pea, opened. It is formed by a single carpel, and dehisces by the ventral and dorsal suture. vv, Valves formed by the two parts of the pericarp. , The epicarp or external layer of the pericarp. ’, Endocarp or internal layer. Between these the mesocarp is situated. g, Seeds placed one over the other, ‘attached to the placenta by short funiculi or cords, ff, The placenta forms a narrow line along the ventral suture, sv. sd, The dorsal suture corresponding to the midrib of the earpellary leaf. Fig. 566. Legume of Bladder-senna (Colutea, arborescens), showing an in- flated, foliaceous pericarp. Fig. 567, Twisted or spiral legume of Medicago. ; 314 INDEHISCENT SYNCARPOUS FRUITS. each other. The seeds are immersed in pulp, and are attached irregularly to the parietes, base, and centre. The fruit has been called Balausta (balaustiwm, flower of pomegranate), and the tough rind is called maticorium (a name applied to it by Pliny). The Pepo or Peponida (xérav, a pumpkin) is illustrated by the fruit of the Gourd, Melon (fig. 430, p. 245), and other Cucurbitaceze, where the calyx is superior, the rind is thick and fleshy, and there are three or more seed-bearing parietal placentas, either surrounding a central cavity, or sending prolongations inwards. The fruit of the Papaw resembles the Pepo, but the calyx is not superior. The Hesperidiwm (golden fruit in the garden of Hesperides) is the name given to such fruits as the Orange, Lemon, and Shaddock, in which the epicarp and mesocarp form a separable rind, and the endocarp sends prolongations inwards, forming triangular divisions, in which pulpy cells are developed so as to surround the seeds which are attached to the inner angle, Both Pepo and Hesperidium may be considered as modifications of the Berry. Fig. 568. Fig. 569. The Pome (pomum, an apple), seen in the Apple, Pear, Quince, Medlar, and Hawthorn, is a fleshy fruit with the calyx attached, and has an outer skin or epicarp, a fleshy mesocarp, and a scaly or horny endocarp, the core enclosing the seeds. Some look upon the so-called epicarp and mesocarp as formed by the prolonged receptacle or torus with a fleshy lining ; while the endocarp represents the true carpels. In this view the endocarp might be regarded as consisting of a number of indehiscent follicles (usually five) surrounded by a pulpy torus. In the Medlar the endocarp (or what may be called the true pericarp) is of a Fig. 568, Fruit of common Medlar (Mespilus germanica). Transverse section showing, e, epicarp; s, Sarcocarp; , Endocarp, forming stony coverings of the seeds. The fruit has been called nuculanium, and the hard central cells pyrene. In the Medlar, as well as in the Apple, Pear, and Quince, the fruit may be considered as composed of stony or parch- ment-like follicles, covered by a pulpy disk. Fig. 569. Fruit of Cernus mascula, com- mon Cornel. 1, Transverse section detaching the upper half of the fleshy portion, s, so as to show the central kernel, n. 2, Transverse section of the fruit through the central por- tion, , showing that it consisted of two loculaments. 1, One of the loculaments empty, the other containing a seed, g. DEHISCENT SYNCARPOUS FRUITS. 315 stony hardness, while the outer pulpy covering is open at the summit. The stones of the Medlar are called pyrene (aiejy, the stone of fruit) ; some apply the term nuculanium (nucula, a nut) to the Medlar. Taking this view of the Pome it may be said to resemble the fruit‘of the Rose, with this difference, that the Rose produces achenes, and the Pome closed follicles. In Cornus mascula (fig. 569, 1, 2) there are two stony cells, n, surrounded by the fleshy epicarp and mesocarp, and as they are close together, and one is often abortive (fig. 569, 2, 1), there is a direct transition to the Drupe. Derniscent Syncarpous Frurrs.—The Capsule (capsula, a little chest). This name is applied generally to all dry syncarpous fruits, which open by valves or pores. The valvular capsule is observed in Digitalis (fig. 541, p. 304), Hibiscus esculentus (fig. 545, p. 304), Cedrela angustifolia (fig. 546, p. 304), Mahogany (fig. 547, p. 305), and Cerastium triviale (fig. 540, p. 303). The porose capsule is seen in the Poppy (fig. 444, p. 249), Antirrhinum majus (fig. 558, p. 308), and Campanula. persicifolia (fig. 557, p. 308). Sometimes the capsule opens by a lid, or by circumscissile dehiscence, and it is then called a Pysidium (pysis, a box), as in Anagallis arvensis (fig. 554, p. 307), Henbane (fig. 555, p. 307), and Monkey-pot (Lecythis). The capsule assumes a screw-like form in Helicteres, and a star-like or stellate form in Illicium anisatum. In certain instances the cells of the capsule separate from each other, and open with elasticity to scatter the seeds. This kind of capsule is met with in the Sandbox tree (Hura crepitans), and other Euphorbiacesx, where the cocci, containing -each a single seed, burst asunder with force (fig. 549, p. 305); and in Geraniaceze, where the cocci, each containing, when mature, usually one seed, separate from the carpophore, and become curved upwards by their adherent styles (fig. 551, p. 306). In the former case, the fruit collectively has been called Regma (é%ymwa, a rupture). The Siliqua (siliqua, a husk or pod) (fig. 552, p. 306) may be con- sidered as a variety of the capsule, opening by two valves; these are detached from below upwards, close to the sutures, bearing thin parietal placentas, which are united together by a prolongation called a replum, or spurious dissepiment dividing the fruit into two. The seeds are attached on either side of the replum, either in one row or in two. When the fruit is long and narrow, it is called Sigua; when broad and short, it is called Silcwla, It occurs in cruciferous plants, as Wallflower, Cabbage, and Cress. The siliqua may be considered as formed of two carpels and two parietal placentas united together so as to form a two-celled seed-vessel. Some say that in its normal state it consists of four carpels, and that two of these are abortive. There are four bundles of vessels in it, one corresponding to each valve, which may be called valvular or pericarpial, and others running along the edge called placental. The replum consists of two lamella. 316 CONFLUENT OR POLYGYNCECIAL FRUITS. It sometimes exhibits perforations, becoming fenestrate (fenestra, a window), At other times its central portion is absorbed, so that the fruit becomes one-celled. Multiple or Polygynecial Fruits which are the produce of several Flowers wnited, It sometimes happens that the ovaries of two flowers unite so as to form a double fruit. This may be seen in many species of Honey- suckle. But the fruits which are now to be considered consist usually of the floral envelopes, as well as the ovaries of several flowers united into one, and are called Multiple, Confluent, or Polygynacial, The term Anthocarpous (dvéos, a flower, xaeréc, fruit) has also been applied as indicating that the floral envelopes as well as the carpels are con- cerned in the formation of the fruit. The Sorosis (cweés, a congeries or cluster) is a confluent fruit formed by a united spike of flowers, which be- comes succulent. The fruit of the Pine-apple (fig. 570) is composed of numerous ovaries, floral enve- lopes, and bracts, combined so as to form a succulent mass. The scales outside, cc, are the modified bracts and floral leaves, which, when the develop- ment of the fruit-hearing spike terminates, appear in the form of ordinary leaves, and constitute the crown, f. Other instances of a sorosis are the Bread- fruit and Jack-fruit. Sometimes a fruit of this kind resembles that formed by a single flower, and a superficial observer might have some difficulty in Fig. 570. marking the difference. Thus, the Strawberry, Raspberry, and Mulberry appear to be very like each other, but they differ totally in their structure. The Strawberry and 7 Raspberry are each the produce of a single flower, the former being a succulent edible receptacle bearing achzenia on its convex surface; the latter being a collection of drupes placed on a conical unpalatable receptacle ; while the Mulberry (fig. 571) is a sorosis formed by numerous flowers united together, the calyces becoming succulent and investing the pericarps. Syconus (ctxoy, a fig) is a confluent anthocarpous fruit, in which the axis, or the extremity of the peduncle, is Fig. 570. Polygyncecial or confluent fruit of Ananassa sativa, Pine-apple. Axis bearing numerous flowers, the ovaries of which are combined with the bracts, ¢ c, to form the fruit. J, Crown of the Pine-apple, consisting of empty bracts or floral leaves. Fig. 571. Antho- carpous fruit of the Mulberry, formed by the union of several flowers. The floral envelopes become succulent, and cover the pistil. CONFLUENT OR POLYGYNCCIAL FRUITS. 317 hollowed, so as to bear numerous flowers, all of which are united in one mass to form the fruit. The Fig (fig. 267, p. 180) is of this nature, and what are called its seeds are the acheenia or monospermal seed- vessels of the numerous flowers scattered through the pulpy hol- lowed axis. In Dorstenia (fig. 266, p. 180) the axis ‘is less deeply hollowed, and of a harder texture, the fruit exhibiting often very anomalous forms. Strobilus (org6B7do¢, fir-cone) is a fruit-bearing spike more or less elongated, covered with scales (fig. 572), each of which represents a sepa- rate flower, and has often two seeds at its base. The scales may be considered as bracts, or as flattened. carpellary leaves or branches, and the seeds are naked, as there is no true ovary present with its style or stigma. This fruit is seen in the cones of Firs, Spruces, Larches, and Cedars, which have received the name of Conifers, or cone-bearers, on this account. The scales of the strobilus are sometimes thick and closely united, so as to form a more or less angular and rounded mass, as in the Cypress (fig. 573) ; while in the Juniper they become fleshy, and are so incorporated as to form a globular fruit like a berry (fig. 574). Theidry fruit of the Cypress, and the succulent fruit of the Juniper, have received the name of Galbulus (galbulus, nut of the cypress). The fruit of the Yew (Taxus baccata) is regarded as a cone reduced to a single naked seed, covered by succulent scales, which unite to form a scarlet fleshy envelope, In the Hop the fruit is called algo a strobilus, but in it the scales are thin and membranous, and the seeds are not naked but are contained in pericarps. Fig. 572. Fig. 574. Fig. 572. Cone of Pinus sylvestris, Scotch Fir, consisting of numerous bracts or floral leaves, each of which covers two winged seeds. These seeds are ealled naked, in conse- quence of not being contained in an ovary, with a style or stigma. Fig. 573. Cone of Cupressus sempervirens, Cypress ; one of the Gymnospermous or naked-seeded plants, like the Pine. Fig. 574. Succulent cone or Galbulus of Juniperus macrocarpa. ¢¢¢e, The different scales or bracts united so as to enclose the seeds, 318 TABULAR VIEW OF CARPOLOGY. TABULAR ARRANGEMENT OF FRUITS. A. Simple or Monogynecial Fruits formed by the gynecium of a single flower, and consisting of one or more Carpels either separate or combined ; thus including Apocarpous, Aggregate, and Syncarpous Fruits. I. Indehiscent Pericarps, 1. Monospermal—usually containing a single seed : ( Achenium (Lithosper- | mum). : Mericarp and Cremocarp | in Umbellifere, and / \ Cypsela in Composite. Achemia enclosed in a hollow fleshy torus, Cynarrhodum (Rose). Separable from the seed . Covered by a dry simple Pericarp. Inseparable from the seed i ‘ é Caryopsis (Grasses). Inflated 7 3 Utricle (Chenopodium). Having a cupulate involucrum . : : Glans (Acorn). Having winged appendages. 5 Samara (Sycamore), Covered by a Pericarp, consisting of Epicarp, Sarcocarp, and Endocarp. Drupe, with a two-valved Endocarp, having divisions extending from its inner surface, Tryma (Walnut). Aggregate Drupes, Htcerio (Raspberry). Drupe (Cherry). 2. Polyspermal—containing two or more seeds : b (Ovary inferior, Placenta parietal, attachment 2 of seeds lost when ripe Bacca (Gooseberry). wa attachment permanent, rind ) Fs z thick and hard . Pepo (Gourd). ‘fp, J Peculiar berried many- -celled fruit, with two ro Bt 1 or more rows of Carpels 5 Balausta (Pomegranate). 2 & | Ovary superior, Placenta central . . Uva (Grape). a 5 | —————— Placenta parietal. Papaw fruit. Having a spongy separable rind, and separable ia 5 rillpy relia ¢ Hesperidium (Orange). "38 | ( Endocarp horny, covered by a fleshy Mesocarp a 3 4 and Epicarp formed by the disk Pome (Apple). S 3 & ) Endocarp stony, covered by a fleshy Mesocarp 7 a Ss and Epicarp formed by the disk Nuculanium (Medlar). II. Dehiscent Pericarps. ( Opening by Ventral Suture only * Follicle (Peony). te Opening by Ventral and Dorsal Suture ‘ Legume (Pea). e Lomentum, a Legume separating into distinct pieces, each containing 2 a seed. (Ornithopus), a kind of Schizocarp. 2 Opening by two valves which separate from a } Siliqua (Cabbage). Ss & Central Replum or Frame . : Silicula (Capsella). ening by Transverse or Circumscissile De- 3 | apne Pyxidium (Henbane). A Opening by several "valves or pores " without 3 Ventral or Dorsal Suture or Replum Capsule (Poppy). g Capsule inferior ‘ ‘ , : Diplotegia (Campanula). nm A long pod-like Capsule . : 3 Ceratium (Glaucium), Opening by separation of elastic Cocci . Regma (Hura). MATURATION OF THE PERICARP. 319 B. Polygneecial or Multiple Fruits formed by the union of several Flowers, and consisting of Floral Envelopes, as well as Ovaries ;i these are Anthocarpous. Hollow Anthocarpous Fruit.—Syconus (Fig). i formed by Indurated or Scaly Catkin.—Stro- bilus (Fir Cone and Hop). Convex Anthocarpous Fruit. . formed by Succulent Spike.—Sorosis (Bread- fruit, Mulberry, Pine-apple), Galbulus (Juniper), Professor Dickson gives the following classification of Fruits (ma- ture pistils), 1. Capsule. Dry, dehiscent, allowing the seeds to escape—Capsule, Siliqua, Follicle, Legume, Regma, Diplotegia, Pyxidium, etc., of authors. 2. Schizocarp. Dry, breaking up into two or more, one- or few-seeded indehiscent pieces—Carcerulus (Malva, Tropwolum, Lamium, etc.), Samara (Acer), Lomentum, Cremocarp, of authors. 8. Achene. Dry, indehiscent, one- or few-seeded, not breaking up as the last - —Achene, Caryopsis, Samara (Frawinus, ete.), Cypsela, Glans, of authors. 4, Berry. Indehiscent. Seeds imbedded in pulp. Outer portion of variable consistence—Uva, Hesperidium, Amphisarca, Pepo, Balausta, Bacca, of authors. 5. Drupe. Indehiscent. Seed or seeds inclosed by the distinctly defined and indurated endocarp. Outer portion of variable consistence (fleshy, fibrous, etc.)— Drupe, Tryma, Pome, of authors.* Where several distinct (apocarpous) fruits are produced from one flower ; the > » term Eterio designates a collection of Achenes, Drupes or Follicles (?), upon a more or less convex receptacle ; and Cynarrhodum a collection of Achenes upon the inner surface of a hollow succulent receptacle. . Where the fruits from an inflorescence are massed together the whole forms a “confluent fruit.” (a) Syconus—Achenes, upon a flat or hollow, dry or succulent axis of inflorescence. (5) Sorosis—Achenes, Drupes, or Berries, with succulent perianths, or succulent bracts, or both, upon 4 more or less elongated axis of inflorescence ;—Sorosis and Galbulus of authors. (c) Strobitus—Achenes, with dry bracts, and sometimes scale-like secondary peduncles, upon a more or less elongated axis of inflorescence. 7, Maturation of the Pericarp. After fertilisation, the parts of the ovary begin to swell, the foramen of the ovule is more or less closed, the stigma becomes dry, and the style either withers and falls off, or remains attached as a hardened process or apiculum ; while the embryo plant is developed in the ovule. Certain fruits, such as Oranges and Grapes, are some- times produced without seeds. It does not appear, therefore, necessary for the production of fruit in all cases, that the process of fertilisation * The above classification is founded upon the idea that the definition or description of a fruit, as such, should involve the structural modification undergone by the pistil in ripen- ing, rather than the origin of the fruit from superior to inferior ovary, etc., which is to be understood or taken for granted, from the description of the immature pistil. From such a principle not being recognised, the terms indicating different fruits have been needlessly multiplied. 320 MATURATION OF THE PERICARP. should be complete. In speaking of seedless Oranges, Dr. Bullar states that the thinness of the rind of a St. Michael Orange, and its freedom from pips, depend on the age of the tree. The young trees, when in full vigour, bear fruit with a thick pulpy rind and abundance of seeds; but as the vigour of the plant declines, the peel becomes thinner, and the seeds gradually diminish in number, till they dis- appear altogether. While the fruit enlarges, the sap is drawn towards it, and a great exhaustion of the juices of the plant takes place. In Annuals this ex- haustion is such as to destroy the plants; but if they are prevented from bearing fruit, they may be made to live for two or more years. Perennials, by acquiring increased vigour, are able better to bear the demand made upon them during fruiting. If large and highly- flavoured fruit is desired, it is of importance to allow an accumulation of sap to take place before the plant flowers. The wood should be well ripened. When a very young plant is permitted to bear fruit, it seldom brings it to perfection. When a plant produces fruit in very large quantity, gardeners are in the habit of thinning it early, in order that there may be an increased supply of sap to that which remains. In this way, Peaches, Nectarines, and Apricots, are ren- dered larger and better flavoured. When the fruiting is checked for one season, there is an accumulation of nutritive matter, which has a beneficial effect on the subsequent crop. + The pericarp is at first of a green colour, and performs the same functions as the other green parts of plants, decomposing carbonic acid under the agency of light, and liberating oxygen. Saussure found by experiments that all fruits in a green state perform this pro- cess of deoxidation. As the pericarp advances to maturity, it either becomes dry or succulent. In the former case, it changes into a brown or a white colour, and has a quantity of ligneous matter deposited in its substance, so as to acquire sometimes great hardness, when it is incapable of performing any active process of vegetable life; in the latter it becomes fleshy in its texture, and assumes various bright tints, as red, yellow, etc. In fleshy fruits, however, there is fre- quently a deposition of ligneous cells in the endocarp, forming the stone of the fruit; and even in the substance of the pulpy matter or sarcocarp there are found isolated cells of a similar nature, as in some varieties of Pear, where they cause a peculiar grittiness. The con- tents of the cells near the circumference of succulent fruits are thick- ened by exhalation, and a process of endosmose goes on, by which the thinner contents of the inner cells pass outwards, and thus cause swelling of the fruit. As the fruit advances to maturity, however, this exhalation diminishes. In all pulpy fruits which are not green there are changes going on by which carbon is separated in combina- tion with oxygen. MATURATION OF THE PERICARP. 321 Dry fruits may remain attached to the tree for some time before they are fully ripe, and ultimately separate by disarticulation. Occasionally, when the pericarp is thick, it separates in layers like the bark. Succulent fruits contain a large quantity of water, along with cellulose, lignine, sugar, gummy matter or dextrine, albumen, colouring matter, various organic acids, as citric, malic, and tartaric, combined with lime and alkaline substances, besides a pulpy gelatinous matter, containing pectose, the characteristic constituent of unripe fruits. This substance is quite insoluble in water, but during the ripening of the fruit it is converted by the vegetable acids into pectine, which is soluble in water, and exists in the pulp of fruits, as Apples, Pears, Gooseberries, Currants, Raspberries, Strawberries, etc. This substance undergoes a further change, being converted into pectic acid (C* H* 0%) and pectosic acid (C* H* 0”). These are easily soluble in boiling water and gelatinise on cooling (axrés, congealed) ; hence their use in making preserves. Each kind of fruit is flavoured with a peculiar aromatic substance. Starch is rarely present in the pericarp of the fruit, although it occurs commonly in the seed. In Plantains, Bananas, and Bread-fruit, however, especially when seedless, there is a considerable quantity of starchy matter, giving rise to mealiness, Oily matters are also found in the cellular tissue of many fruits. Thus, a fixed oil occurs in the Olive, and essential oils in the Orange, Lemon, Lime, Rue, Dictamuus, etc. During ripening much of the water disappears, while the cellulose, lignine, and the dextrine, are converted into sugar. Berard is of opinion that the changes in fruits are caused by the action of the oxygen of the air. Fremy found that fruits covered with varnish did not. ripen. As the process of ripening becomes perfected the acids com- bine with alkalies, and thus the acidity of the fruit diminishes, while ‘its sweetness increases. The formation of sugar is by some attributed to the action of organic acids on the vegetable constituents, gum, dex- trine, and starch; others think that the cellulose and lignine are similarly changed by the action of acids. The sugar of fruits is grape or starch sugar, called also Glucose. Its formula is C’ H* 0". In the Grape, when young, there is abundance of tartaric acid; but as the fruit advances to maturity this combines with potash, so as to diminish the acidity. Certain fruits owe their aperient qualities to the saline matter which they contain, In seasons when there is little sun, and a great abundance of moisture, succulent fruits become watery, and lose their flavour. The same thing frequently takes place in young trees with abundance of sap, and in cases where a large supply of water has been given artificially. The following analysis of the Cherry in its unripe and ripe state, as given by Berard, exhibits generally the chemical composition of suc- culent fruits :— Y 322 MATURATION OF THE PERICARP. Unripe. Ripe. Chlorophyll ‘ ‘ 3 . 0°05 5 é : — f Sugar . zs ‘ : ¢) Le F : - 18°12 Gum or dextrine ” 6°01 r F Z 3°23 Cellulose . ‘ ‘ 7 . 2°44 ‘ , 5 1°12 Albumen . : : 3 . 0°21 2 ‘ ‘ 0°57 Malic Acid 3 a 19%5 : ‘ ‘ 2°01 Lime s : i é . O14 3 “ . 0'10 Water 3 3 4 . . 88:28 é ‘ ‘ 74°85 100°00 100°00 The following table shows the changes produced on the water, sugar, and cellulose, in 100 parts of unripe and ripe fruits :— Water. Sugar. Cellulose. Unripe. Ripe. Unripe. Ripe. Unripe. Ripe. Apricot . . . 89°39 74:87. . 664 1648. . 3°61 1°86 Peach . . . 90°31 80°24. . 0°63 11°61. . 38°01 1°21 Cherries . . . 88°28 74°85. . 1:12 1812. . 2°44 1°12 Plums . . 7487 7110. . 17°71 «24°81. . 1:26 1:11 Pears ‘ . 86°28 83°88. . 6°45 11°52. . 38°80 2:19 It is not easy in all cases to determine the exact time when the fruit is ripe. In dry fruits, the period immediately before dehiscence is considered as that of maturation ; but, in pulpy fruits, there is much uncertainty. It is usual to say that edible fruits are ripe when their ingredients are in such a state of combination as to give the most agreeable flavour. This occurs at different periods in different fruits. After succulent fruits are ripe, in the ordinary sense, so as to be capable of being used for food, they undergo further changes, by the oxidation of their tissues, even after being separated from the plant. In some cases these changes improve the quality of the fruit, as in the case of the Medlar, the austerity of which is thus still further diminished. In the Pear, this process, called by Lindley bletting (from the French, blest), renders it soft, but still fit for food; while in the Apple it causes a decay which acts injuriously on its qualities. By this process of oxi- dation the whole fruit is ultimately reduced to a putrefactive mass, which probabl¥’ acts beneficially in promoting the germination of the seeds when the fruit drops on the ground. The period of time required for ripening the fruit varies in dif ferent plants. Most plants ripen their fruit within a year from the time of the expansion of the flower. Some come to maturity in a few days, others require some months. Certain plants, as some Conifere, require more than a year, and in the Metrosideros the fruit remains attached to the branch for several years. The following is a general statement of the usual time required for the maturation of different kinds of fruit :— EFFECT OF GRAFTING ON FRUITS. 323 Grasses. : ; “ . 18 to 45 days, Raspberry, Strawberry, Cherry . : : % ‘ 2 months. Bird-cherry, Lime-tree je 2 a % Roses, White-thorn, Horse- chestnut ‘ 4 Vine, Pear, Apple, Walnut, Beech, oc Nut, Almond, ‘5 to 6 7 ” ” 2 Olive, Savin . . ae Colchicum, Mistleto . é ‘ ‘ : 3 to9 ,, Many Conifere . F » 10tol2 ,, Some Conifer, certain species of Oak, Metrosideros, above 12 ,, The ripening of fruit may be accelerated by the application of heat, by placing dark-coloured bricks below it, and by removing a ring of bark so as to lead to an accumulation of sap. It has been observed that plants subjected to a high temperature not unfrequently prove abortive, which seems to result from the over-stimulation causing the production of unisexual flowers alone. Trees are sometimes made to produce fruit by checking their roots when too luxuriant, and by preventing the excessive development of branches. GraFrrinc.—A very important benefit is produced, both as regards the period of fruiting and the quality of the fruit, by the process of grafting. This is accomplished by taking a young twig or scion, called a graft, and causing it to unite to a vigorous stem or stock, thus enabling it to derive a larger supply of nutritive matter than it could otherwise obtain, and checking its vegetative powers. In place of a slip or cutting, a bud is sometimes taken. In order that grafting may be successfully performed, there must be an affinity between the graft and the stock as regards their sap, etc. It has often been sup- posed that any kinds of plants may be grafted together, and instances are mentioned by Virgil and Pliny, where different fruits are said to have been borne on the same stock. This was probably produced by what the French call greffe des charlatans,—cutting down a tree within a short distance of the ground, and then hollowing out the stump, and planting within it several young trees of different species ; in a few years they grow up together so as to fill up the cavity, and appear to be one. The deception is kept up better if some buds of the parent stock have been kept alive. Fortune gives an instance in the Punjaub of a Peach growing out of an old Mango tree about six or eight feet from the ground. In this case the Peach had its roots in the ground, and had grown through the hollow stem of the Mango. In India the Peepul tree (Ficus religiosa) occasionally grows on the stumps of other trees, and sends its roots down so as to cover the stump completely, and thus presents the appearance of two kinds of trees growing from one root. By grafting the branches of hedge plants together good fences are occasionally formed (see drawing of such hedges and trees, Trans, Bot. Soc, Edin., vol. x. p. 452). The object which gardeners wish to secure by grafting, is the improvement of the kinds of fruit, the perpetuation of good varieties, 324 DIFFERENT MODES OF GRAFTING. which could not be procured from seed, and the hastening of the period of fruit-bearing. Grafting a young twig on an older stock has the effect of making it flower earlier than it would otherwise do. The accumulation of sap in the old stock is made beneficial to the twig, and a check is given at the same time to its tendency to produce leaves. Although the general law is, that grafting can only take place between plants, especially trees, of the same family, there are certain exceptions, Loranthaceous parasites can form a union with genera in different orders, Mr. Knight did much to improve fruits by grafting. He believed, however, that a graft would not live longer than the natural limit of life allowed to the tree from which it had been taken. In this way he endeavoured to account for the supposed extinction of some valuable varieties: of fruit, such as the Golden pippin, and many cider apples of the seventeenth century. He conceived that the only natural method of propagating plants was by seed. His views have not been confirmed by physiologists. Many plants are undoubtedly propagated naturally by shoots, buds, and tubers, as well as by seed ; and it is certain that the life of slips may be prolonged by various means, much beyond the usual limit of the life of the parent stock. The Sugar-cane is propa- gated naturally by the stem, the Strawberry by runners, the Couch-grass by creeping stems, Potatoes and Jerusalem Artichokes by tubers, the Tiger lily by bulblets, and Achimenes by scaly bodies like tubers. The fruits, moreover, which Mr. Knight thought had disappeared, such as Red streak, Golden pippin, and Golden Harvey, still exist, and any feebleness exhibited by them does not appear to proceed from old age, but seems to be owing to other causes, such as the nature of the soil, cold, violence, and mutilation. Vines have been transmitted by perpetual division from the time of the Romans. A slip taken from a Willow in Mr. Knight’s garden, pronounced by him as dying from old age, was planted in the Edinburgh Botanic Garden many years ago, and is now a vigorous tree, although the original stock has long since undergone decay. It is true, however, that a cutting taken from a specimen already exhausted by excessive development of its parts will partake of the impaired vigour of its parent, and will possess less con- stitutional energy than that taken from a vigorous stock. In grafting, various methods have been adopted. One of these is grafting by approach, or inarching, when two growing plants are united together, and after adhesion one is severed from its own stock, and left to grow on the other. This kind of adhesion sometimes takes place naturally in trees growing close together. The branch of the same tree may also be bent, so as to become united to the stem at two points. This is often seen in the Ivy. The roots of contiguous trees occasion- ally unite by a process of grafting, and to this is attributed the con- tinued vigour of the stump of Spruce-trees cut down on the Swiss mountains. This natural grafting of roots has been observed in the DIFFERENT MODES OF GRAFTING. 325 White Pine (Abies pectinata), and sometimes in the Red Pine (Abies excelsa), as well as in the Scotch Fir (Pinus sylvestris) and the Larch (Laria europea), The usual method of grafting is by sctons or slips, which are applied to the stock by a sloping surface, or are inserted into slits in it by cleft-grafting, or into perforations by wimble- or peg-grafting. Whip- grafting or tongue-grafting is performed by inserting a tongue or cleft- process of the stock between the lips of a cut in the scion, Side-grafting resembles whip-crafting, but it is performed on the side of the stock without heading it down. Sometimes several slips are placed ina circular manner round the inside of the bark of the stock by crown- grafting ; or the bark of a portion of the stock is removed, and that of the scion is hollowed out, so as to be applied over it like the parts of a flute, hence called flute-grafting. Budding is practised by the removal of a bud from one plant, along with the portion of the bark and new wood, and applying it to another plant, in which a similar wound has been made.. Grafting is usually performed between the woody parts of the plants, but herbaceous parts may also be united in this way. The graft and stock are secured by clay, or by bees’-wax and tallow, or by Indian rubber, gutta percha, or collodion. By grafting, all our good varieties of apples have been produced from the Crab Apple. The seeds of the cultivated apples, when sown, produce plants which have a tendency to revert to the original sour Crab. Grafted varieties can only be propagated by cuttings. The influence exercised by the stock is very marked, and it is of great importance to select good stocks on which to graft slips. In this way the fruit is often much improved by a process of ennobling, as it is called. The scion also seems in some cases to exercise a remarkable effect on the stock. Slips taken from plants with variegated leaves, and grafted on others with non-variegated leaves, have sometimes caused the leaves of the latter to assume variegation, and the effect, when once established, has continued even after the slip was removed. The effects of grafting are well seen in the case of the Red Laburnum, when united to the Yellow species. The Red Laburnum is a hybrid between the common Yellow Laburnum and Cytisus purpureus (the Purple Laburnum). The branches below the graft produce the ordinary Yellow Laburnum flowers of large size; those above exhibit often the small Purple Laburnum flowers, as well as reddish flowers, intermediate between the two in size and colour, Occasionally, the same cluster has some flowers yellow and some purplish. 8.—Seed or Fertilised Ovule arrived at Maturity. While the pistil undergoes changes consequent on the discharge of the pollen on the stigma, and ultimately becomes the fruit, the 326 SEED OR MATURE OVULE. ovule also is transformed, and, when fully developed, constitutes the seed. After fertilisation, the foramen of the ovule contracts, the young plant gradually increases in its interior, by the absorption of the fluid matter contained in the sac of the amnios (embryo-sac), solid nutritive matter is deposited, and a greater or less degree of hardness is acquired. The seed then is the fecundated mature ovule containing the embryo, with certain nutritive and protective append- ages. When ripe, the seed contains usually a quantity of starchy and ligneous matter, azotised compounds, as caseine and vegetable albumen, oily and saline matters. It sometimes acquires a stony hardness, as in the case of the seed of Phytelephas macrocarpa, which yields vegetable ivory. Care’must be taken not to confound seeds with single-seeded pericarps, such as the Achznium and Caryopsis, in which a style and stigma are present; nor with bulbils or bulblets, as in Lilium bulbiferum and Dentaria bulbifera, which are germs or separable buds developed without fecundation. Seeds are usually enclosed in a seed-vessel or pericarp, and hence the great mass of flowering plants are called angiospermous (dyyoc, or ayyesiov, a vessel, and oréewa, a seed). In Coniferee and Cycadacee, however, the seeds are generally looked upon as having no true pericarpial covering, and fertilisation therefore takes place by the direct application of the pollen to the seed, without the intervention of stigma or style. Hence the seeds, although sometimes protected by scales, are truly naked, and the plants are called gymnospermous Fig.575. — (yuwvés, naked, and owégua, a seed). Occasionally, by the early rupture of the pericarp, seeds originally covered become exposed. This is seen in Leontice and Cuphea. In Mignonette, the seed-vessel (fig. 575) opens early, so as to expose the seeds, which are called seminude, Besides being contained in a pericarp, the seed has its own peculiar coverings. Like the ovule, it consists of a nucleus or kernel, and integuments. In some instances, although rarely, all the parts of the ovule are visible in the seed—viz., the embryo-sac or quintine, the quartine, the tercine or covering of the nucleus, the secundine, and the primine. In fig. 576 there is a representation of the seed of Nymphea alba, in which se indicates the embryo-sac, containing the embryo, ¢; ~, the cellular farinaceous covering (quartine), formed round the embryo-sac; mf, membrane formed round the nucleus (tercine) ; mi, the secundine ; ¢, the primine. In general, however, great changes take place by the development of the embryo; the embryo-sac is often absorbed, or becomes incorporated with the cellular tissue of the nucleus ; the same thing occasionally takes place ©) Fig. 575. Fruit or capsule of Mignonette (Reseda odorata), opening early, so that the ovules become seminude, SEED OR MATURE OVULE. 327 in the secundine, so that in the ripe seed, all that can be detected is the embryo with two coverings, The general covering of the seed is called spermoderm (origua, seed, and dégua, covering). In order to correspond with the name applied to the covering of the fruit, it ought more properly to be denominated perisperm (regi, around, and oégua, seed). This latter term, however, has been appropriated to a certain portion of the seed, to be after- wards noticed under the name of albumen, Tue SPERMODERM usually consists of two parts an external membrane, called the episperm or testa (277, upon, or on the out- side, and ovégua, a seed ; testa, a shell), and an internal membrane, called endopleura (évdov, within, and rAzved, side or rib), The former may consist of a union of the primine and secundine, or of the primine only, when, as occasionally happens, the secundine is ab- sorbed; the latter, of a combination be- tween the membrane of the nucleus and the embryo-sac, or of one of these parts alone. Sometimes the secundine remains distinct in the seed, forming what has been called a mesosperm (“éo0g, middle) ; and when it assumes a fleshy character, it has re- ceived the name of sarcosperm or sarcoderm (odeé, flesh). Tue Episperm consists of cellular tissue, which often assumes various colours, and becomes more or less hardened by depositions in its interior. In Abrus pre¢atorius and Adenanthera pavonina it is of a bright red colour ; in French beans it is beautifully mottled ; in the Almond it is veined ; in the Tulip and Primrose it is rough; in the Snapdragon it is marked with depressions ; in Cotton and Ascle- pias it has hairs attached to it; and in Mahogany and Bignonia it is expanded in the form of wing-like appendages. In Collomia, Acan- thodium, and other seeds, it contains spiral cells, from which, when moistened with water, the fibres uncoil in a beautiful manner. Spiral cells are also seen in the episperm of the seeds of Cobza and’ Calem- pelis scaber. In the episperm of the seed of Ulmus campestris the cells are compressed, and their sinuous boundaries are traced out by minute rectangular crystals adhering to their walls. Fig. 576. Fig. 576. Young seed of Nymphea alba cut vertically. jf Funiculus or umbilical cord. a, Arillus derived from the placenta. 7, Raphe. ec, Chalaza or cotyledonary end of the seed. h, Hilum or base of the seed. m, Micropyle or foramen. ¢, Testa or primine, mi, Secundine. mt, Tercine or membrane of the nucleus. », Farinaceous external perisperm or albumen formed by the nucleus, and probably constituting the quartine of Mirbel. se, se, Internal perisperm or endosperm formed by the embryo-sac, e, The embryo. 328 SEED OR MATURE OVULE. THe ENnpDopLeura is also cellular. It is often thin and trans- parent, but it sometimes becomes thickened. It is applied more or less closely to the embryo, and sometimes follows a sinuous course, forming folds on its internal surface, and separating from the episperm. When the embryo-sac remains distinct from the nucleus in the seeds, as in Nymphzea, Zingiber, Piper, ete., it forms a covering to which the name of vitellus (vitellus, yolk of an egg) was given by Geertner. Aritius. Sometimes there is an additional covering to the seed, derived from an expansion of the funiculus or placenta after fertilisa- tion, to which the name arillus has been given. This is seen in the Fig. 577. Passion-flower, where the covering commences at the base, and proceeds towards the apex, leaving the foramen uncovered. In the Nutmeg and Spindle-tree this additional coat is said to commence at the side of the exostome, and to proceed from above downwards, constituting, in the former case, the substance called mace; and, in the latter, the Fig. 578, bright scarlet covering of the seeds (figs. 577, 578). In such instances Fig. 577. 1, 2, 8, 4, Various states of the arillus of the spindle-tree (Euonymus). The figures show the mode in which it is developed from the edges of the foramen. aaaa, Aril- lode. fff, Foramen or Exostome. Fig. 578. Development of the same arillus, a, around the ovule, o, exhibited in a different position. 1, 2, 3, 4, are four successive stages of development. In fig. 4 the arillus has been cut vertically to show its relation to the ovule, which it surrounds completely. SEED OR MATURE OVULE. 329 it has been called by some an arillode, This arillode, after growing downwards, may be reflected upwards, so as to cover the foramen. On the testa, at various points, there are pro- duced at times cellular bodies, which are not _dependent on fertilisation, to which the name of strophioles (strophiolum, a little garland), or car- uncules (caruncula, a little piece of flesh), has been given, the seeds being strophiolate or carunculate. These tumours may occur near the base or apex of the seed, they may be swellings of the exostome, as in Ricinus (fig. 579 c), or they may occur in the course of the raphe. Fig. 579. Seeds are attached to the placenta by means of a funiculus or umbilical cord, which varies much in length. In Magnolias it attains a great length, and when the seed is ripe it appears like a cord sus- pending it from the follicle. The point of the seed by which it is united to the cord, or the scar left on its separation, is called the hilum or umbilicus, and represents its base. The hilum frequently exhibits marked colours, being black in the Bean, white in many species of Phaseolus, etc. It may occupy a small or large surface, according to the nature of the attachment. In the Calabar bean and in some species of Mucuna and Dolichos it extends along a large portion of the edge of the seed. The part called the foramen in the ovule becomes the micropyle (wimeés, small, and ran, gate) of the seed, with its exostome and endostome. This may be recognisable by the naked eye, as in the Pea and Bean tribe, Ivis, etc., or it may be very minute and microscopic. It indicates the true apex of the seed, and is important as marking the part to which the root of the embryo is directed. At the micropyle in the Bean is observed a small process of integument, which, when the young plant sprouts, is pushed up like a lid, and is called embryotega (tego, I cover). The fibro-vascular bundles, from the placenta pass through the funiculus and reach the seed, either entering it directly at a point called the omphalode (supaAéc, navel), which forms part of the hilum, or being prolonged between the outer and inner integument in the form of a raphe (é@p4, a seam), and reaching the chalaza (yaad, a pimple or tubercle), or organic base of the nucleus, where a swelling or peculiar expansion may often be detected, as in Crocus. In fig. 576 the spiral vessels, 7, are seen entering the cord, f, passing through the hilum, 4, forming the raphe, ”, between the testa, t, and endopleura, mi, and ending in the chalazal expansion, c. So also Fig. 579. Vertical section of a carpel of Ricinus communis, and of the seed which it contains. a, Pericarp. 2, Loculament. jf, Funiculusor umbilical cord. ¢, Integuments of the seed, having at their apex a caruncula, c, which is traversed by the small canal of the exostome. The exostome does not correspond exactly with the endostome, which is imme- diately above the radicle. 7, Raphe. ch, Chalaza. p. Perisperm or albumen, the upper portion of which only is seen. ¢, Embryo, with its radicle, er, and its cotyledons, ec. 330 SEED OR MATURE OVULE. in fig. 577, where f is the funiculus, r the raphe united to the hilum, and chalaza, c, whence vessels, n, penetrate the seed. In some seeds, as Narthecium ossifragum, the vessels are said not to appear till after fertilisation, and in Habenaria viridis none have been detected. The chalaza is often of a different colour from the rest of the integuments, In the Orange it is of a reddish- brown colour, and is easily recognised at one end of the seed when the integuments are carefully removed. Sometimes, however, its structure can only be recog- nised by careful dissection. It indicates the cotyle- donary extremity of the embryo. The hilum and Fig. 580. chalaza may correspond, or they may be separated from each other and united by the raphe (fig. 580). The raphe is generally on the side of the seed next the ventral suture.’ The positions of the hilum, micropyle, and chalaza, are of importance in determining the nature of the seed. The hilum is the base of the seed, and the micropyle its apex, while the chalaza is the organic base of the nucleus. The hilum and chalaza may correspond, the micropyle being at the opposite extremity, and then the seed is orthotropal (286s, straight). The seed may be curved so that the micropyle is close to the hilum, and the chalaza, by the growth of the seed on one side, may be slightly removed from the hilum, then the seed is campylotropal (xardaos, curved). The micropyle may be close to the hilum, and the chalaza in the progress of development may be removed to the opposite end, then the seed is anatropal (dvargérw, I reverse).* The position of the seed as regards the pericarp resembles that of the ovule in the ovary, and the same terms are applied—erect, ascend- ing, pendulous, suspended, curved, ete. (figs. 459, 460, 461, 462, 456, pp. 257, 255). These terms have no reference to the mode in which the fruit is attached to the axis. Thus the seed may be erect while the fruit itself is pendent, in the ordinary meaning of that term. The part of the seed next the axis or the ventral suture is its face, the opposite side being the back. Seeds exhibit great varieties of forms. They may be flattened laterally, compressed; or from above downwards, depressed, They may be round, oval, triangular, polygonal, rolled up like a snail, as in Physostemon; or coiled up like a snake, as in Ophiocaryon paradoxum. The object of fertilisation is the formation of the embryo in the interior of the seed. In general, one embryo is produced, constituting what is denominated monembryony (uévos, one); but in Conifer, Cycadacez, Mistleto, etc., there are frequently several embryos, giving Fig, 580. Seed of the Hazel. f, Funiculus. 7, Raphe. c, Chalaza. mn, Veins spreading in a radiating manner over the integuments of the seed. * See pp. 255, 256, where these terms are more fully explained when treating of the ovule. SEED OR MATURE OVULE. 331 tise to what is called polyembryony (woAus, many). Sometimes two embryos become united together in the same seed. In the coniferous seeds numerous corpuscles are seen, whence the embryos proceed. The process of fertilisation has already been traced until the embryo appears as a rounded cellular body, enclosed in the embryo-sac, and attached to a suspensor. In fig. 576, ¢ is the embryo, and se the embryo-sac, In this sac there is at first a protoplasm, in which cells are developed. The embryonic cell (fig. 581 ), still attached to the sac by its suspensor, s, contains distinct nucleated cells (fig. 581, 2). These gradually multiply, and form at length a cellular mass, at first undivided (fig. 581, 3 ¢), but afterwards showing a separation of parts, so that the axis and lateral projections or rudiments of leaves can be distinguished. Figs. 584. 585, Fig. 581. Fig, 583. Fig. 586. Fig. 587. In figs, 582 to 587 all the stages of the formation of embryo can be traced; appearing first as a simple cell (figs. 582, 584), forming others in its interior (figs. 585, 586); and finally, the parts of the embryo becoming visible, figs. 583, 587, where g r is the axis representing the stem and roots, and c’c are the lateral projections, which are developed as leaf-like bodies, called cotyledons (xoriAnddv, the name of a plant having leaves like seed-lobes). PERISPERM OR ALBUMEN.—As the embryo increases in size it gradually causes absorption of the cellular tissue in the embryo-sac, and it is sometimes developed to such a degree as to reduce the nucleus and embryo-sac to a thin integument. In such a case the seed consists of | Fig. 581, First development of the embryo of Draba verna. 0, Suspensor, which in this plant is very long. v, Embryonic or germinal vesicle. e, Embryo. 1, First stage, in which the embryonic vesicle only is seen. 2, Second stage, showing several cells formed in the embryonic vesicle. 38, Third stage, in which the embryo becomes more conspicuous in consequence of the formation of numerous small cells. Fig. 582. Monocotyledonous embryo of Potamogeton perfoliatus in its early stage, appearing as a vesicle or simple cell. Fig. 583. The same, further advanced, showing radicle, r, gemmule or plumule, g, and the cotyledon, c. Fig. 584. Dicotyledonous embryo of Cinothera crassipes in its early stage, appearing as a vesicle or cell. Fig. 585. The same, further advanced, showing three united utricles or cells. Fig. 586. The same, more developed, showing numerous cells. Fig. 587, The same in a more developed state, showing radicle, r, gemmule, g, and cotyle- dons, cc, 332 PERISPERM OR ALBUMEN OF THE SEED. integuments and embryo alone. In Santalum, Osyris, and Loranthus, Griffith says the ovule is sometimes reduced entirely to a sort of embryonary sac. In Avicennia the embryo, at its maturity, is on the outside of the nucleus and body of the ovule. In other cases it enlarges to a certain extent, filling the embryo-sac completely or partially, and . only encroaching slightly on the cells of the nucleus. The cells sur- rounding the embryo then become filled with a solid deposit called albumen, consisting of starchy, oily matter, and nitrogenous compounds, To this some have applied the term perisperm (qeg/, around, and ovégua, seed); others, that of endosperm (¢vdov, within). The name, perispermic albumen, or perisperm, is often restricted to that found in the cells of the nucleus alone, outside the embryo-sac (fig. 576 n); endospermic albumen, or endosperm, to that found within the embryo-sac alone (fig. 576 se), as in Chelidonium majus, Ranunculacese, Umbelliferee, and in many Endogens, etc. Sometimes both kinds of albumen occur Fig. 588. Fig. 589. Fig. 590. in the same seed, as in Nympheeaceze and Piperaceze. In some instances the albumen is produced in the region of the chalaza. In some Scrophu- larias the embryo-sac forms little cavities or bags, which in the ripe seed remain as appendages to the albumen, Seeds in which the embryo occupies the entire seed, are called exalbwminous (ex, without), as Composite, Cruciferze, and most Leguminose, while others having separate albumen are albuminous. The larger the quantity of albumen in a seed the smaller the embryo. In figs. 588 to 590 the relative proportion which the embryo bears to the albumen or perisperm in different seeds is shown ; ¢ being the embryo with its cotyledons and young root, p the perisperm, ¢ the coverings of the seed, f the funiculus or cord, & the hilum, and ¢ the chalaza. In fig. 588 the embryo is Fig. 588. Anatropal mature seed of Helleborus niger, cut vertically. The embryo, e, is small, as compared with the perisperm or albumen, p. t, Spermoderm or coverings of the seed. f, Funiculus. h, Hilum. ce, Chalaza. Fig. 589. Mature seed of Diphylleia peltata, showing an embryo, e, which occupies a larger portion of the seed than in fig. 588. Letters indicate the same parts as in the previous figure. Fig. 590. Ripe seed of Berberis vulgaris, exhibiting a larger embryo, e, as compared with the perisperm, p. Letters as in figs, 588 and 589. PERISPERM OR ALBUMEN OF THE SEED. 333 minute, and occupies only a small part of the apex of the albumen; in fig. 589 it is larger, and has encroached on the perisperm ; while in fig. 590 it is still more developed, much of the albumen having been absorbed. - The albumen varies much in its nature and consistence, and fur- nishes important characters. It may be farinaceous or mealy, consisting chiefly of cells filled with starch (fig. 591), as in Cereal grains, where it is abundant ; fleshy or cartélaginous, consisting of thicker cells which are still soft, as in the Coco-nut, and which sometimes contain oil, as in the oily albumen of Croton (fig. 592), Ricinus, and Poppy ; horny, when the matter in the cells is of a hard consistence, and often arranged in a concentric manner, so as nearly to fill the entire cavity, as in Date, Ivory-Palm, and Coffee. The albumen may be uniform throughout, or it may present a mottled appearance, as in the Nutmeg, the seeds of Anonaceze, and some Palms (fig. 593), where it is called ruminated, This mottled appearance depends often on the endopleura Fig. 591. Fig. 592. or inner integument forming folds on which the albumen is deposited, and when the seed is ripe these foldings of the membrane divide the albumen in a sinuous or convoluted manner. The albumen is a store of matter laid up for the nourishment of the embryo. In the Coco-nut and double Coco-nut it forms the great bulk of the seed, weighing many ounces, while the embryo is minute, weighing a few grains, and lies in a cavity at one extremity. In Coffee the albumen is the horny portion, the infusion of which is used for a beverage. In Phytelephas it is called vegetable ivory from its hardness, and is used for the same purposes as ivory. In the horny albumen of this Palm, as well as in that of the Attalea funifera, the Date, and the Doom Palm, the concentric deposition of secondary layers, leaving a Fig. 591. Section of a small portion of the farinaceous perisperm or albumen of Zea Mais, Indian corn. cec, Cells. fff, Grains of starch in the cells. Fig. 592. Section of a small portion of the oily perisperm or albumen of Croton Tiglium, cccc,Cells, hhh, Drops of oil contained in the cells. Fig. 593. Vertical section of the fruit of Areca Catechu, c, Perianth. jf, Pericarp. p, Ruminated perisperm or albumen, e, Embryo. 334 PARTS OF THE EMBRYO PLANT. small cavity in the centre of the cells, and radiating spaces uncovered with thickening matter, is well seen under the microscope. The embryo consists of cotyledons or rudimentary leaves, the plumule (plumula, a little feather), or gemmule (gemma, a bud), repre- senting the ascending axis, radicle (radix, root), or the descending axis, and their point of union the collum, collar or neck ; that part of a the axis which intervenes between the collar and cotyledons pi: being the caulicule (cauliculus, a little stalk), or tigelle (tigellus, ki” a little stalk). The embryo varies in its structure in the dif- Fig. 594. ferent divisions of the vegetable kingdom. In acrogenous and thallogenous plants it continues as a cell or spore, with granular matter in its interior (fig. 594), without any separation of parts or the produc- P Fig. 595. Fig. 596. Fig. 597. tion of cotyledons. Hence these plants are called acotyledonous (a priva- tive, xortAndav). Endogenous and Exogenous plants, on the other hand, exhibit a marked separation of parts in their embryo, the former having one cotyledon, and hence being monocotyledonous (évos, one) ; the latter two, and hence dicotyledonous (dé, twice). Thus, the whole vegetable kingdom is divided into three Classes by the nature of the embryo, the first of which classes corresponds with the cryptogamic division of plants, the second with the endogenous division of phanerogamous or flowering plants, the third with the exogenous division of the same. Fig. 595 represents a monocotyle- donous embryo, with its cotyledon, c ; while figs, 596 and 597 exhibit a dicotyledonous embryo, with its cotyledons, ¢ c. THE SporE of acotyledonous plants (fig. 594) is a cellular body, Fig..594. Acotyledonous embryo of Marchantia polymorpha. Such embryos bear the name of spores. Fig. 595. Monocotyledonous embryo of Potamogeton perfoliatus nearly mature. r, Radicle. ¢, Caulicule or tigellus. c, Cotyledon. g, Gemmule or plumule. Fig. 596. Mature dicotyledonous embryo of the common Almond. 1, Radicle or young root. Fig. 597. The same, with one of the cotyledons removed. r, Radicle. ¢, Tigelle or caulicule. c, One of the cotyledons left. ic, Cicatrix left at the place wliere the other cotyledon was attached. g,Gemmule composed of several small leaves, PARTS OF THE EMBRYO PLANT. 335 from which a new plant is produced. Germination takes place in any part of its surface, and not from fixed points. It sometimes presents filaments or vibratile cilia on its surface (figs. 467-470, p. 265), by means of which it moves about in fluids, like some of the Infusoria. When it germinates, these cilia disappear. Sometimes spores are united in definite numbers, as in fours, surrounded by a cellular covering, or perispore (qegi, around, and ozogd, offspring), or sporidium, and thus forming the reproductive body called a tetraspore {rereds, four), which is common in Algz (fig. 482, p. 273). Empryo.—tIn the embryo or corculum (corculum, a little heart), the first part formed is the awis, having one of its extremities turned towards the suspensor, and the other in the opposite direction ; the former indicating the point whence the young root or radicle is to proceed, and the latter that whence the leafy stem is to arise. The part which produces the first leaves or cotyledons is called the cotyle- donary extremity of the embryo, while the other is the radicular extremity. The radicular extremity is thus continuous with the suspensor, and consequently points towards the micropyle (fig. 590 h), or the summit of the nucleus, an important fact in practical botany ; while the cotyledonary, being opposite, is pointed towards the base of the nucleus or the chalaza (fig. 590 c). Hence, by ascertaining the position of the micropyle and chalaza, the two extremities of the. embryo can in general be discovered. In some rare instances, in consequence of a thickening in the coats of the seed, as in Ricinus (fig. 579, p. 329), and some other Euphorbiacew, there is an alteration in the micropyle, so that the radicle does not point directly to it. The part of the axis which unites the radicle and the cotyledon or cotyledons is denominated caulicule or tigelle (figs. 595 t, 597 t). This is sometimes very short. From the point where the cotyledons are united to the axis a bud is developed (in the same way as from the axil of leaves); this bud contains the rudiments of the true or primordial (primus, first, and ordo, rank) leaves of the plant, and has been called plumule or gemmule. This bud may be seen usually lying within the cotyledons, Thus in fig. 597 the embryo of the Almond exhibits the gemmule, g, lying on one of the cotyledons, the other having been removed and leaving "a cicatrix, ic; while in fig. 595 the gem- mule, g, of Potamogeton perfoliatus is covered by the single cotyledon, ¢. The gemmule as well as the cotyledon at are sometimes obscurely seen, Thus in Fig. 598. Fig. 599. Fig. 598. Spiral embryo of Cuscuta or Dodder. Fig. 599. Embryo of Caryocar buty- rosum, #, Thick tigelle or caulicule, forming nearly the whole mass, becoming narrowed and curved at its extremity, and applied to the groove, s. In the figure this narrowed portion is slightly separated from the groove, ¢, Two rudimentary cotyledons. 336 MONOCOTYLEDONOUS EMBRYO. ‘ Cuscuta (fig. 598) the embryo appears as an elongated axis without divisions ; and in Caryocar butyrosum (fig. 599) the mass of the embryo is made up by the radicular extremity and tigelle, ¢, in a groove of which, s, the cotyledonary extremity lies embedded, which when separated, as in the figure, shows only very small cotyledons. In some monocotyledonous embryos, as in Orchidacez, it requires a micro- scopic examination to detect the cotyledonary leaf. MonocoryLeponous Empryo.—In this embryo the single coty- ledon in general encloses the gemmule at its lower portion, and exhibits on one side a small slit (fig. 600 f), which indicates the edges of the vaginal or sheathing portion of the cotyledonary leaf. The embryo presents commonly a cylindrical form, rounded at the extremities, or a more or less elongated ovoid (fig. 600). At first sight there seems to be no dis. tinction of parts; but on careful examination, by moisten- ing the embryo, and making a vertical section, there will be detected, at a variable height, a small projecting mammilla, buried a little below the surface. This is the gemmule which marks the termination of the axis. From the lower extremity proceeds the radicular portion (figs. 595 é7, 600 r), which may be said to represent both the tigelle and radicle. The upper portion or chalazal end of the embryo is the cotyledon (figs. 595, 600 c), which is sheathing at its base, so as to enclose the gemmule. In some cases, as in the com- mon oat (Avena sativa), there is a peculiar process which covers the plumule, and which is considered by some as an axillary stipule of the cotyledon. The length of the radicular portion, or that below the gemmule, varies. It is usually shorter than the cotyledon, and is denser in structure ; but in some instances it becomes much larger, giving rise to what has been called a macropodous embryo (maxgés, long, and rods, a foot). Thus, in fig. 601, ¢ represents the long radi- cular portion in the young state, whence ultimately the root, 7, proceeds. Occasionally, the radicular portion becomes very thick and large, so as to form a considerable portion of the embryo; and in all monocotyledons it may be considered as an enlarged mammillary projection, whence the rootlets (adventitious roots) proceed, by bursting through it, and carrying with them a covering or sheath, coleorhiza (fig. 105, p. 42). When considering endogenous or monocotyledonous stems, it was shown that the leaves are produced singly and alternately, in a sheathing manner, each embracing the subsequently developed bud. So it is in the monocotyledonous embryo. There is a single leaf or cotyledon produced, and if in any instance there is more than one, it Fig. 600. Embryo of Triglochin Barrelieri. 7, Radicle. f, Slit corresponding to the gemmule. c, Cotyledon. DICOTYLEDONOUS EMBRYO. 337 is alternate with the first formed. In the Oat an abortive organ called the epiblast (SAaorés, a shoot) is produced, which may be con- sidered a rudimentary second cotyledon. The cotyledon (fig. 600 c) is folded either partially, as in Dioscorea, or completely. Its sheathing portion (vagina) embraces the bud or gemmule, which appears as a mam- millary projection ; its position being indi- cated by a cleft or slit (fig. 600 f, p. 336), where the edges of the sheath unite. All the portion of the embryo above the gemmule is the cotyledon ; all below, the radicle. DicotyLeponovus Empryo.—tThe form of this embryo varies much ; and although sometimes resembling in its general aspect that of monocotyledons, yet it is always distinguished by a division taking place at the cotyledonary extremity, by which it is separated. into two, more or less evident, lobes. The parts of this embryo are easily traced in the Bean, Pea, Acorn, and Almond. In the latter (fig. 596) the embryo has an oval form, consisting of two thick cotyle- dons, cc, and a radicle,r, When one of the cotyledons is removed (fig. 597), leaving scars, tc, the gemmule or plumule, g, is seen included between them, with its cauli- cule or tigelle, ¢. The cotyledons are not always, however, of the same size. Thus, in a species of Hireea (fig. 602), one of them, co’, is smaller than the other; and in Carapa guianensis (fig. 603) there appears to be only one, in consequence of the intimate union which takes place between the two, as indicated by the dotted line, c. The union between the cotyledonary leaves may continue after the young plant begins to germinate. Such em- bryos have been called pseudo-monocotyle- donous (pevdjs, false). When there are two cotyledons, they are opposite to each . other, In some cases there are more than two present, and then Fig, 601. t, a Fig. 601. Monocotyledonous embryo of Zannichellia palustris germinating. m, Collum or neck, the point intermediate between the stem or tigelle, ¢, and the radicle or root, r. ce, Cotyledon. g, Gemmule or plumule. ; Z 338 DICOTYLEDONOUS EMBRYO. they become verticillate. This occurs in Conifers, especially in the Fir (fig. 604), Spruce, and Larch, in which six, nine, twelve, and even fifteen have been observed. In such cases it is probable that the cotyledons are split by collateral chorisis, and thus divided into several. They are linear, and resemble in their form and mode of development the clustered or fasciculated leaves of the Larch. Plants having numerous cotyledons are occasionally denominated polycoty- ledonous, Duchartre thinks that the multiple cotyledons of the Firs Fig. 602. Fig. 603. Fig. 604. are not verticillate, but occur in two opposite groups, placed like two ordinary cotyledons. Hence he considers the plants to be truly dicotyledonous, with the cotyledons deeply divided into a number of segments. Between the two cotyledons there is a slit which is well seen in Pinus Pinaster and excelsa. Thus, the arrangement of the cotyledons follows the same law as that of the leaves in dicotyledonous or exogenous plants, being opposite or verticillate according to the mode of formation of the axis. In Welwitschia there are two coty- ledons which last throughout its life (more than a century), and in the course of time they grow to an enormous size, being sometimes six feet long and two or three in breadth. They constitute the only leaves of the plant. In species of Streptocarpus the cotyledons are also permanent and act the part of leaves. One of them is frequently largely developed, while the other is small or abortive. The texture of the cotyledons varies. They may be thick, as in the Bean, exhibiting only slight traces of venation, with their flat internal surfaces in contact, and their backs more or less convex ; or they may be in the form of thin and delicate lamine, flattened on both Fig. 602. Embryo of Hirsa Salzmanniana, cut vertically, to show'the inequality of the two cotyledons, one of which, c, forms almost the whole mass of the embryo. c’, The small coty- ledon, g,Gemmule or plumule, 7, Radicle. Fig. 603. Embryo of Carapa guianensis, cut vertically to show the union of the cotyledons, the distinction between which is only indicated by a faint line, c. 7, Radicle. g, Gemmule, Fig. 604. Embryo of Fir. 1, Taken from the seed. 2, Beginning to germinate. 1, Radicle. «, Cotyledons, which are numerous ; the plant being polycotyledonous, DICOTYLEDONOUS EMBRYO. 339 sides, and having distinct venation, as in Ricinus (fig. 605), Jatropha, Euonymus, etc. In the former case they are called fleshy, or seminal lobes ; in the latter, foliaceous, or seminal leaves. Cotyledons are usually entire and sessile. But they occasionally become lobed, as in the Walnut and the Lime (fig. 606), where the cotyledon, c, has five lobes; or petiolate, as in Geranium molle (fig. 607 p); or auriculate, as in the Ash (fig. 608 0). Like leaves in the bud (see Vernation, p. 110), cotyledons may be either applied directly to each other (fig. 605), or may be folded in various ways. In the Fig. 608. Fig. 609. Fig. 610. Fig. 611. Almond (fig: 596) they lie in the direction of the axis. In other cases they are folded laterally, conduplicate (fig. 609) ; or from apex to base, reclinate (fig. 222 a, p. 111); or rolled up laterally, so as partially to embrace each other, convolute (fig. 610); or rolled up like the young fronds of ferns, circinate (fig. 611). In these cases, both cotyledons follow the same direction in their foldings or convolutions, but, in other instances, they are folded in opposite directions, resembling the Fig. 605. Embryo of Ricinus communis taken out of the seed (see fig. 579, p.’829), and cut transversely. The two halves are separated so as to show the two cotyledons, ¢, applied to each other. 1, Radicle. Fig. 606. Embryo of the Lime. 1, Radicle. c¢, One of the divided or palmate cotyledons, Fig. 607, Embryo of Geranium molle. r, Radicle. c, Cotyledons attached to the collar by a stalk or petiole, p. Fig. 608. Embryo of the Ash. 7, Radicle. c, one of the cotyledons. 00, Auricular appendages to the cotyledon. Fig. 609. Embryo of Brassica oleracea, Cabbage. 7, Radicle. c, Cotyledon. 1, Entire embryo. 2, Embryo cut transversely, showing the cotyledons folded on the radicle or conduplicate. The radicle is dorsal, or on the back of the cotyledons. Fig. 610. Embryo of Punica Granatum, Pomegranate, cut into two halves. The upper half removed to show the convolute coty- ledons. c, Radicle. Fig. 611. Circinate embryo (spirolobez) of Bunias orientalis, 340 DICOTYLEDONOUS EMBRYO. equitant (fig. 222 m, p. 111) and semi-equitant (fig. 222 n, p. 111) vernation. : The radicle may be either straight or curved, and, in particular instances, it gives a marked character to the seed. Thus, divisions of the order Cruciferze are founded on the relative position and folding of the radicle and cotyledons, In the division Plewrorhizew (aheugd, side, and £/Z«, root), the cotyledons are applied by their faces, and the radicle (figs. 612, 613 r) is folded on their edges, so as to be lateral, while the cotyledons, c, are accumbent (accwmbo, I lie at the ay ig. 612. Fig. 614. side). In Notorhizee: (vwros, the back) the cotyledons (fig. 614 c) are applied to each other by their faces, and the radicle, r, is folded on their back, so as to be dorsal, and the cotyledons are incumbent (incumbo, I lie upon, or on the back). In Orthoplocee (dgé6¢, straight, and whoxh, a plait) the cotyledons are conduplicate (fig. 609, 1, 2, c), while the radicle, 7, is dorsal, and enclosed between their folds. In other divisions, the radicle is folded in a spiral manner (fig. 611), and the cotyledons follow the same course. In the Dodder (fig. 598) the embryo appears as an axis without divisions, having several turns of the spiral on different planes. The seed sometimes is composed of the embryo and integuments alone, the former being either straight or folded in various ways, as already shown. In other cases there is an addition of perisperm or nutritive matter, in greater or less quantity, according to the state of development which the embryo attains (figs. 588, 589, 590), When the embryo is surrounded by the perisperm on all sides except its radicular extremity (fig. 590, p. 332), it becomes internal or intrarius (intra, within) ; when lying outside the perisperm, and only coming into contact with it at certain points, it is external or extrarius (extra, Fig. 612. Embryo of a Pea, cut transversely. Upper half separated to show the fleshy accumbent cotyledons, c. 7, Radicle applied laterally, Fig. 613. Embryo of Isatis tinctoria. e, Accumbent cotyledons. 7, Radicle. 1, Embryo entire. 2, Transverse section of the embryo. Fig. 614. Embryo of Cheiranthus Cheiri, Wallflower. c, Incumbent cotyledons. r, Radicle. 1, Embryo entire. 2, Transverse section of the embryo. POSITION AND FORM OF THE EMBRYO. _ 341 without). When the embryo follows the direction of the axis of the seed, it is awile or awial, and it may be either external, so as to come into contact with the perisperm only by its cotyledonary apex (fig. 615), or internal (figs. 588, 589, 590, see p. 332). In the latter case, the radicular extremity may, as in some Coniferze, become incorporated with the perisperm apparently by means of a thickened suspensor. When the embryo is not in the direction of the axis, it becomes abawile or abawial (fig. 616 ¢); and in this case it may be either straight or curved, internal or external. In the straight seed of Grasses the perisperm is abundant, and the embryo lies at a point on its surface immediately below the integuments, being straight and external. In Campylotropous ovules the embryo is curved, and in place of being embedded in perisperm, is frequently external to it, following the concavity of the seed (fig. 618), and becoming peripheri- cal (asgipigw, I carry round), with the chalaza situated in the curva- ture of the embryo. ; It has been already stated that the radicle of the embryo is directed to the micropyle, and the cotyledons to the chalaza. In some cases, by the growth of the integuments, the former is turned round so as not to correspond with the apex of ‘the nucleus, and then the embryo has the radicle directed to one side, and is called excentric, as is seen in Primulacex, Plantaginacee, and many Palms, especially the Date (fig. 616). The position of the embryo in different kinds of seeds varies. In an orthotropal seed the embryo is inverted or antitropal (dvr, opposite, rgévw, I turn), the radicle pointing to the apex of the seed, or to the part opposite the hilum (fig. 617), Thus, fig. 619 represents an orthotropal seed of Sterculia Balanghas, at- Fig. 615, Grain of Carex depauperata, cut vertically. ¢, Integuments. », Perisperm. ¢, Embryo. Fig. 616. Seed or kernel of the Date. yp, Perisperm or horny albumen. e, Embryo. 1, Entire seed. 2, Seed cut transversely at the point where the embryo, ¢, is situated, Fig. 617. Winged fruit of Rumex, cut vertically to show the abaxile or abaxial slightly curved embryo. Fig. 618. Carpel of Mirabilis Jalapa, cut vertically, with the . eed which it contains. a, Pericarp crowned with the remains of the style, s. t, Integu- ments of the seed orspermoderm. e, Peripherical embryo, with its radicle, 7, and its coty- ledons, ¢. , Perisperm or albumen surrounded by the embryo. 342 ” POSITION AND FORM OF THE EMBRYO. tached to the pericarp, pc, by the funiculus, f/ The chalaza and hilum are confounded together at ch, the micropyle being at the opposite end. The integuments of the seed, ¢, cover the embryo with its perisperm, ps; the coty- ledons, c, point to the hilum and chalaza ; while the tadicle, r, points to the micropyle, and the embryo is thus reversed or inverted. Again, in an anatropal seed (figs. 589, 590, p. 332), where the micropyle is close to the hilum, and the Fig. 619. Fig. 620. chalaza at the opposite extremity, the embryo is erect or homotropal (dmoos, like, and reérw, I turn), the radicle or base of the embryo being directed to the base of the seed. In some anatropal ovules, as in Castor oil (fig. 579, p. 329), the exostome is thickened or carunculate, c, and the endostome does not correspond exactly to it, so that P the radicle, er, of the embryo is directed to a point a little removed from the exostome, In curved or campy- lotropal seeds (fig. 455, p. 255) the embryo is folded so that its radicular and cotyledonary extremities are ap- proximated, and it becomes amphitropal (d&u@i, around, reerw, I turn). In this instance the seed may be exalbuminous, and the embryo may be folded on itself (fig. 620), or albuminous, the embryo surrounding more or less completely the perisperm, and being peripherical (fig. 618). In fig. 620 the seed of Erysimum cheiran- thoides is shown, with the chalaza, ch, and the hilum, A, nearly confounded together, the micropyle, m, the embryo occupying the entire seed, with the radicle, 7, folded on the cotyledons, c, which enclose the plumule, gy. Thus, by determining the position of the hilum, chalaza, and micropyle, the direction of the embryo may be known. According to the mode in which the seed is attached to the Fig. 619. Orthotropal seed of Sterculia Balanghas, cut longitudinally, with the portion of the pericarp, yc, to which it is attached. , Funiculus. ch, Chalaza and hilum con- founded together. t¢, Integuments of the seed, or spermoderm. ps, Perisperm, the sum- mit of which only is seen. c, One of the cotyledons. The other cotyledon has been re- moved to show the gemmule, g. 7, Radicle which is directed to the foramen at the apex of the seed. The embryo is antitropal or inverted. Fig. 620. Campylotropal seed of Erysimum cheiranthoides, cut longitudinally. m, Micropyle. ch, Chalaza not far removed from the hilum, h. t, Testa or episperm. mi, Inner covering of the seed or endopleura. r, Radicle. c, Cotyledons. g, Gemmule. The embryo is curved or amphitropal. Fig. 621. Vertical section of the carpel of Triglochin Barrelieri. , Pericarp crowned by the sessile stigma, s. g, Seed. jf, Funiculus. 7, Raphe. c, Chalaza, Fig. 621. FUNCTIONS OF THE SEED. 343 pericarp, the radicle may be directed upwards or downwards, or laterally, as regards the ovary. In an orthotropal ovule, attached to the base of the pericarp, it is superior (fig. 617). So also in a suspended anatropal ovule, as in fig. 579, p. 329. In other anatropal ovules, as in figs. 588, 600, 621, the radicle is inferior. When the ovule is horizontal as regards the pericarp (fig. 619), the radicle, r, is either centrifugal, when it points to the outer wall of the ovary; or centripetal, when it points to the axis or inner wall of the ovary. 9.— Functions of the Seed. The seed contains the embryo or germ, which, when placed in favourable circumstances, is developed as a new plant. The embryo is usually of a whitish or pale colour, resembling the perisperm when present, and sometimes scarcely distinguishable from it at first sight. Occasionally, however, it is of a greenish or yellow hue. Instances of this occurs in the perispermic or albuminous seed of Euonymus, and the aperispermic or exalbuminous seeds of most Crucifere. The changes which take place in the composition of the seed, and in its coats, are with the view of protecting the embryo from vicissitudes of temperature, moisture, etc., and of laying up a store of nourish- ment for its after growth. The coats become thickened and hardened by the deposition of lignine; and in its interior, starch, nitrogenous compounds, phosphates, and sulphates, besides oily and fatty matters, various organic acids, tannin, and resins, are found. The specific gravity of the seed is much increased, so that it usually sinks in water, and it becomes more capable of resisting decomposition, and preserv- ing the vitality of the embryo. In some instances where air is con- tained in their envelopes seeds float in water. When seeds are matured, they are detached from the plant in various ways. They separate from the funiculus at the hilum, and remain free in the cavity of the pericarp, which either falls along with them, or opens in various ways so as to scatter them. The elasticity with which some seed-vessels open during the process of desiccation is very great. It may be seen in Hura crepitans, Common Broom, and Cardamiine. In the Geranium (fig. 551, p. 306) the seed-vessels are coiled upwards on the elongated beak, and in this way the seeds are dropped. In the Cyclamen the peduncle curves towards: the earth so as to place the seed-vessels in a position suitable for germina- tion. In the succulent fruit of Ecballium Elaterium, or squirting Cucumber, the cells vary in their size and contents in different parts ; and by the force of endosmose a rupture of the valves takes place at their weakest points—viz., where they are united to the peduncle. By the elasticity of the valves the seeds and fluid contents are sent out with great force through the opening left by the separation of the 344 GERMINATION—REQUISITES FOR IT. peduncle. In the Balsam (Impatiens noli-me-tangere) the seed-vessel opens with force by a similar process, the five valves curving inwards in a spiral manner, in consequence of the distension of the outer large cells. The seeds are discharged before they are dry. In the Mig- nonette (fig. 575, p. 326) the seed-vessel opens early, so as to expose the seeds ; and in Cuphea the placenta bearing the seeds pierces the ovary and floral coverings, and is raised above them. Fleshy fruits, which fall to the ground when ripe, supply by their succulent portion the most suitable nutriment for the young embryo in its earliest stages of growth. Wind, water, animals, and man, are instrumental in the dissemina- tion of seeds. Some seeds, as those of Mahogany, Bignonia, Tecoma, Pine, Asclepias, Epilobium, and the Cotton plant, have winged or hairy appendages, by means of which they are wafted to a dis- tance. The same thing occurs in some indehiscent seed-vessels, as the samara of the Sycamore and Ash, and the achenia’of Dandelion, Thistles, etc. Moisture, as well as dryness, operates in the bursting of seed-vessels. The pod of the Rose of Jericho (Anastatica hiero- chuntina), and the capsule of some Fig-marigolds (Mesembryanthe- mum Tripolium) exhibit the effects of moisture in a remarkable degree. Animals, by feeding on fleshy fruits, the kernels of which resist the action of the juice of the stomach, disseminate seeds ; and man has been the means of transporting seeds from one country to another. In some cases the pericarps ripen their seeds under ground, and are called hypocarpogean (iaé, under, xaerés, fruit, yéu, 77, earth). This is seen in the Ground nut (Arachis hypogeea). Other plants, as Vicia amphicarpos, have both aerial and subterranean fruit. Many seeds are used for food by animals, and a great destruction of them takes place from decay ; but this is compensated for by the vast number pro- duced, so as to secure the continuance of the species. The quantity of seeds produced by many plants is very great. In single capsules of Poppy and Tobacco upwards of 40,000 have been counted. GERMINATION.—The act by which the embryo of a seed leaves its state of torpidity, and becomes developed as a new plant, is called germination (germinatio, springing). In order that this process may go on, a certain combination of circumstances is necessary. The chief requisites are moisture, air, and a certain temperature. Exclusion from light is also beneficial. In Cotyledonous plants germination may be defined as the act by which the fecundated embryo of a seed leaves the state of torpor in which it has remained for a longer or shorter period, starts into life, as it were, comes out from its envelope, and sustains its existence until such time as the nutritive organs are developed. Moisture is necessary in order that the nutritive matters may be taken up in a state of solution, and that certain changes may take | GERMINATION—REQUISITES FOR IT. 345 place in the seed. Dry seeds will not germinate. Until water be absorbed no circulation of fluids in the seed can take place. The quantity of water absorbed by seeds is often very large. Decandolle found that a French bean, weighing 544 millegrammes, absorbed 756 of water. The swelling of Peas by absorption of water is familiar to all, The-kernels or seeds of stone-fruits by this means are enabled to burst their hard coverings. / The temperature required for germination varies in different seeds. Some demand a tropical heat, others are satisfied with the warmth of our spring. In general, the requisite temperature may be said to vary from 60° to 80° F. Some seeds can bear a temperature which would kill others. Some have been known to germinate after ex- posure for a short time to the heat of boiling syrup; others after exposure to a cold of -39° F. Cereals and beans can only bear immersion in water at 110° F. for a few minutes. In steam they will bear 140° F. ; and in dry air 170° F. Many plants grow in the immediate vicinity of very hot springs, others in cold regions. Edwards and Colin, from their experiments, were led to fix 95° F. as the highest limit of prolonged temperature which cereal grains can bear in water; and 113° F. as the highest they can bear in sand or earth. Vegetable life has been observed progressing under much higher temperatures. In the Manilla Islands, a hot spring, which raised the thermometer to 187°, had plants flourishing in it and on its borders. A species of Chara grows in the hot springs of Iceland, and various Conferve in the boiling springs of Arabia and of the Cape of Good Hope. Dr. Hooker states that on the edge of hot springs in the valley of the Soane in India, the temperature of which was sufficient to boil eggs, there occurred sixteen species of flower- ing plants—Desmodium, Oldenlandia, Boerhaayvia, some Composite, Grasses, and Cyperaceze. Moseley noticed specimens of Botryococcus, Braunia, Diatoms, and other Algz, in the hot springs of Furnas in the Azores. Hooker found Conferve in the hot springs of Bel- cuppee on the Behar Hills, at 168° F. Cyperaceze grew in water of 100° F. Dr. Wood of California found Nostoc calidarium and Chry- sococcus thermophilus in the hot springs of Benton, at 160° F. Abel mentions an Arenaria growing in soil at a temperature of 110° F. Cyperus polystachius and Pteris longifolia were found by Schouw in very hot soil which burnt the hand. Wheat, Oats, and Barley, are said to thrive in any country where the mean temperature exceeds 65° F. The spores of certain cryptogamic plants are especially fitted for cold countries. Edwards and Colin found that seeds in a dry air bore a higher temperature than in water or steam. . Air, or rather owygen, was shown by Scheele to be necessary for germination. Seeds deeply buried in the soil, and excluded from air, do not spring. The depth at which seeds should be sown varies 346 GERMINATION—-REQUISITES FOR IT. from half-an-inch to two inches, according to the nature of the soil. The following experiments were made by Petri :— Seed sown to the Came above ground No. of plants that depth of i came up. F ANCD scswmoserewcnenes vas 7-8ths dL acie eg teeia Roveaeeniee Nears all. De sig sechenatiaada teat sores ieta 7-8ths. D> ay. gue aiwaenavdaawnreeas 6-8ths he aie aici nahas arenas 4-8ths, age, Cupehane aye Gala ic eet Senso 3-8ths. 6 1-8th. Shallow sowing is thus proved to be the best. Seeds, when buried deep in the soil, sometimes lie dormant for a long time, and only germinate when the air is admitted by the process of subsoil ploughing, or other agricultural operations. When ground is turned up for the first time it is common to see a crop of white clover and other plants spring up, which had not been pre- viously seen in the locality. After the great fire in London, plants sprang up, the seeds of which must have long lain dormant; and the same thing is observed after the burning of forests and the draining of marshes. Gardner says that the name capoeira is given in Brazil to the trees which spring up after the burning of the virgin forests (matos virgens), and that they are always very distinct from those which constituted the original vegetation. Mr. Vernon Harcourt mentions a case where turnip seeds lay in a dormant state for seven or eight years, in consequence of being carried down to a great depth in the soil. On the Calton Hill, at Edinburgh, when new soil was turned up some years ago for building, a large crop of Fumaria mic- rantha sprang up; and seeds gathered from under six feet of peat- moss in Stirlingshire have been known to germinate. A weak solution of chlorine is said to accelerate germination, probably by the decom- position of water, and the liberation of oxygen. Weak solutions of chlorate of potash, of nitric acid, and of oxalic acid, are also said to accelerate the sprouting of seeds, Darkness is favourable to germination. Seeds germinate best when excluded from light. M. Boitard showed this by experiments on Auricula seeds, some of which were covered by a transparent bell- jar, others by a jar of ground glass, and a third set by a jar enveloped in black cloth. The last germinated most rapidly. Senebier con- cluded that the height and size of a plant were proportionate to the intensity of the illumination, its verdure dependent on the quality of the rays. Mr. Hunt says that the luminous or light-giving rays, and those nearest the yellow, have a marked effect in impeding germina- tion; the red or heat-giving rays are favourable to the process, if abundance of water is present ; while the blue rays, or those concerned % GERMINATION—REQUISITES FOR IT. 347 in chemical action or actinism, accelerate the process and cause rapid growth. His experiments were performed by making the sun’s rays pass through different kinds of coloured glass. He believes that the scorching effect of the sun on leaves may be prevented by the use of blue glass, and that a high temperature might be obtained by red glass. He has suggested a pale-green glass made with oxide of copper, as that best fitted for conservatories. By this means he expects that the scorching rays of light will be excluded, while no hindrance is given to the passage of the others; the green colour being a compound of yellow or luminous, and of blue or chemical rays. A delicate emerald-green glass has been employed, at his suggestion, in glazing the large Palm-house at Kew. Tn order that plants may germinate vigorously, moisture, heat, and air must be supplied in due proportion. If any of them are deficient, or in excess, injury may be done. It is of great importance, therefore, in agricultural operations, that the ground should be well pulverised, the seeds regularly sown at a proper and equal depth, and the soil drained. Pulverised soil, when examined, is found to consist of small particles having cavities in their interior, and separated from each other by interstitial spaces. In a very dry soil, all these cavities are full of air; in a very wet undrained soil, they are full of moisture ; in a properly drained soil, the interstices are full of air, while the particles themselves are moist. The seed in such a soil is under the influence of heat, air, and moisture, and is excluded from light. Hence it is in very favourable circumstances for germination. Great. attention should be paid to the temperature of the soil in which seeds are sown. Frost has an important effect in pulverising the soil, by the expansion of the water contained in the particles, when it is con- verted into ice. Snow, again, acts in giving a covering to the young plant, protecting it from intense frost and sudden alternations of temperature, and by its slow melting allows the plant to accom- modate itself to the mild atmosphere, Snow contains often much oxygen. ; If a field is not equally planted, the seeds will sink to different depths, and will spring up very irregularly. In ordinary productive soils seeds should be placed at a depth not greater than two inches, Draining acts not merely in removing superfluous moisture, but in allowing a constant renewal of nutritive matter, more especially of ammonia and carbonic acid from the atmosphere, in giving a supply of air, and in keeping up a proper temperature in the soil. In an undrained soil the water is stagnant, and there is little supply of fresh nutriment, and much cold is produced. There has been a dis- cussion as to whether shallow or deep draining is the best. Much depends on the nature of the soil, and it is impossible to lay down any fixed rule applicable to all cases, Mr. Smith says that drains in 348 VITALITY OF SEEDS—ITS DURATION. very stiff soils should be fifteen feet apart, and in very light soils thirty or forty ; the depth being from thirty to thirty-six inches, and the main drains six inches deeper than the parallel ones. In extremely stiff clays he makes drains two and a half feet deep. He was the first to advocate the system of parallel drains, or what is called thorough-draining. Viratity or SzEDs.—Some seeds lose their vitality soon, others retain it for a long time. Coffee seeds, in order to grow, require to be sown immediately after ripening. On the other hand, Melon seeds have been known to retain their vitality for upwards of forty years, and those of the Sensitive plant for more than sixty years. Oily seeds in general lose their vitality quickly, probably from their power of ab- sorbing oxygen, and the chemical changes thus induced. Considerable discussions have taken place as to the length of time during which seeds will retain their germinating powers. Lindley mentions a case in which young plants were raised from seeds found ‘in an ancient barrow in Devonshire, along with some coins of the Emperor Hadrian ; and M. des Moulins relates an instance of seeds capable of germinating, which were discovered in a Roman tomb, supposed to be fifteen or sixteen centuries old. In these instances, it is to be remarked that the seeds were protected from the influences required for growth, and were preserved in circumstances which cannot be easily imitated. The statements relative to the germination of Mummy Wheat, that is to say, grain actually deposited in the case along with the mummy, have not been confirmed, and there are many sources of fallacy. With the view of preserving seeds, it is of importance that they should be thoroughly ripened, kept in a uniform temperature, and in a dry state, and not directly exposed to the oxygen of the air. They are often best kept in their seed-vessels. The hard coverings of many foreign legumes, and of the cones of Firs, etc., seem to be of importance in preserving the germinating power of seeds. Seeds not fully ripened are very apt to decay, and are easily affected by moisture. Seeds, although fit for food, may have lost their germinating power. Corn, pulse, and farinaceous seeds generally, will live for a long time if gathered ripe, and preserved quite dry. In sending seeds from foreign countries, they should be put up into dry papers and exposed to free ventilation in a cool place ; as, for instance, in a coarse bag suspended in a cabin. Oily seeds, and‘ those containing much tannin, as beech- mast, acorns, and nuts, must not only be ripe and dry, but also must be excluded from the air. When transported they are often put into dry earth and sand, and pressed hard, the whole being covered with tin, and put into astout box. Some have suggested their preservation in hermetically-sealed bottles full of carbonic acid gas, Earthenware bottles, containing ordinary soil, moderately dry, are useful for the con- veyance of seeds. A common wooden box, about 10 inches square, with TRANSPORTATION OF SEEDS. 349 the sides ? of an inch thick, is also suitable for the purpose. In the box may be put alternate layers of eartli and seeds, the whole being pressed firmly together. Seeds enveloped in wax sent from India germinated well. They had been kept for three months, and were quite firm and fresh. Spanish Chestnuts and Filberts have been sent enveloped in wax to the Himalaya, and are now growing there. Cuttings of fruit- trees, with their ends enveloped in wax, were also sent, and arrived in a living state. In this way also, apples, pears, and plums have been sent. Living plants are best transported in Wardian Cases (fig. 622), and seeds and fruits may also be put in the earth of the Cases. When plants are sent in pots the Case may be divided into separate com- partments, as shown in fig. 623, each compartment containing only Fig. 622 ao = a de Sie QE Cel be Fig. 623. Fig. 624, one pot (fig. 624). The pots should be enveloped in moss, and they should be kept in their place by means of fine galvanised iron-wire. The bottom of the Case should be perforated with six or eight holes, in order to allow the escape of superfluous moisture. Strong white cotton may be used in some instances for covering the Case in-place of glass ; the cotton to be moistened from time to time during transit, M. Alphonse Decandolle made experiments on the vitality of seeds. Fig. 622. Wardian Case, used for transporting living plants and germinating seeds. The top may be glazed with thick glass, or strong white cotton may be firmly stretched over it. Fig. 623. Wooden partitions, which may be inserted in the Case to hold pots, which must be carefully fastened to prevent injury during transit, Fig. 624. Section of the Case, showing the separate pots, with plants, in the interior. 350 CHANGES IN THE SEED DURING GERMINATION. He took 368 species of seed, fifteen years old, collected in the same garden, and sowed them at the same time, and in the same circum- stances as nearly as possible. Of the 368 only 17 germinated, and com- paratively few of the species came up. The following are the results :— Per cent, Malvacee 5 came up out of 10 species 5 . 0°50 Leguminose 9en" as » 45 5, 5 . 0°20 Labiate . A ood a9 + 380 4, ; s 0:03 Scrophulariaceze ¥ OY 5 gy LOE 5 3 . 0°00 Umbellifere 0 4 a9 LO as H . 0°00 Caryophyllacez Oe ays sa Gr ss ‘i . 0°00 Graminez Way we) (ORs Cass . ~ 000 Cruciferz Oh! <5 se OR as : - 0°00 Composite é | ae sy ADD, z . 0°00 In 357 species, of which the duration of life was known, the results ‘were :— > Per cent. Annuals . F . 9 came up out of 180 species 50 Biennials . : ae OO gy 9 28 oy. 0-0 Perennials 4 4, sx 105-5, 3°8 Ligneous . OP) 338 we 55 67 16 357 44 Ligneous species thus seem to preserve the power of germinating longer than others, while biennials are at the opposite end of the scale ; perennials would appear to lose their vitality sooner than annuals, Large seeds were found to retain the germinating power longer than small ones, and the presence or absence of separate albumen or perisperm did not seem to make any difference. Composite and Umbellifere lost their germinating power very early. From these experiments Decandolle concludes that the duration of vitality is frequently in an inverse proportion to the rapidity of the germination. : CHEMICAL CHANGES DURING GERMINATION.— During the process of germination certain changes take place in the contents of the seed, by which they are rendered fit for the nourishment of the embryo. In exalbuminous or aperispermic seeds, where the embryo alone occupies the interior, these changes are effected principally in the matters stored up in the cotyledons. In albuminous or perispermic seeds, on the other hand, the changes occur in the substance of the perisperm. One of the most remarkable of these changes is the conversion of starch into dextrine and grape sugar by a process of oxidation, the object being the conversion of an insoluble into a soluble substance. While this conversion of starch into sugar proceeds, oxygen is absorbed, carbonic acid is given off, and heat is produced. It is probable that at this period there is a certain amount of electric disturbance. Carpenter states that the conversion of the starch of the seed into sugar involves STAGES OF GERMINATION. 351 the liberation of carbonic acid, with a small quantity of acetic acid ; and as all acids are negative, and like electricities repel each other, it is probable that the seed is at the time in an electro-negative condition. The phenomena of germination are well seen in the malting of barley, -which consists in the sprouting of the embryo and the formation of sugar. The changes produced in the air by germinating seeds have been investigated by Saussure, who showed that in all cases carbonic acid was evolved at the expense of the carbon of the seed. During growth and evolution it would appear that all living beings, whether plants or animals, give out carbonic acid (carbon dioxide), whilst oxy- gen or some oxidising substance is absorbed. Growth and evolution must be considered in a different way from the decomposition of CO, by leaves, under the influence of light, to provide the starch, gum, sugar, and other materials that are to be organised. When all the requisites for germination are supplied, the seed, by the absorption of moisture, becomes softened and swollen. When albumen or the perisperm is present, it undergoes certain chemical changes by the action of the air and water, so as to be rendered fit for the nutrition of the embryo. These changes consist partly in the conversion of starch into sugar, and are accompanied with the evolu- tion of carbonic acid, and the production of heat. As the fluid ‘matters are absorbed by the cells of the embryo, the latter continues to increase until it fills the cavity of the seed, and ultimately bursts through the softened integuments. In cases where there is no peri- sperm, the exalbuminous embryo occupies the entire seed, and the process of germination goes on with greater rapidity. The embryo speedily swells, ruptures the integument, and is nourished at the -expense of the cotyledons, which are often fleshy, containing much starchy matter, as in the Bean and Pea, along with oily matter, as in the Nut and Rape seed. There are thus two stages of germination— that in which the embryo undergoes certain changes within the seed itself, and that in which it protrudes through the integuments and becomes an independent plant. The embryo, nourished at the expense of its perisperm and coty- ledons, continues to grow, and usually protrudes its radicular extremity (fig. 625, 1) in the first instance, which is nearest the surface, and next the micropyle. This, which in the embryo is very short, and -confounded with the cauliculus so as to form the first internode, becomes thickened by addition to its extremity (fig. 625, 2), and the ‘division between the ascending ‘and descending axis becomes more marked. The caulicule or axis also elongates, bearing at its summit the plumule, which now appears outside the integuments (fig. 625, 3 9), forming the second internode, either accompanied by the cotyledons, or leaving them still within the seed coats, In the latter case, the -cotyledons are usually fleshy and of a pale colour, and become 352 DIRECTION OF PLUMULE AND RADICLE. gradually absorbed like the perisperm. In the former they assume a more or less leafy aspect, exercis- ing the functions of leaves for a certain period, and ultimately decay- ing. While the radicle descends towards the centre of the earth, pro- ducing roots of a pale colour, the plumule has a tendency to ascend, forming the leafy axis, and assuming a green colour under the influence of light and air. Direction or PLUMULE AND Rapictz.—Various attempts have been made to explain the ascent of the plumule and the descent of the radicle, but none of them are satisfactory. Physiologists have not been able to detect any law to which they can refer the phenomena, although certain agencies are obviously concerned in the effects, Some have said that the root is especially influenced by the attraction of the earth, while the stem is influenced by light. Experiments have shown that the direction of the root is not owing,to the moisture of the soil, and that the ascent of the stem is not due to the action of light and air; for roots descend, and stems ascend, even when the latter are placed in contact with the earth, and the former submitted to the action of light, Knight thinks that the direction of stem and roots may be traced to gravitation, and the state of the tissues. When a branch is horizontal, the fluids gravitate towards the lower side; a vigorous growth takes place there; the tissues enlarge, and, by increasing more than those on the upper side, an incurvation is pro- duced, the convexity of which looks downwards, and thus the extremity of the branch is directed upwards. Again, in the root the increase takes place by the extremity, and the fluids by their gravity cause this to retain always a descending direction. A similar explanation is given by Dodart. Dutrochet refers the phenomena to endosmose, which varies in its effects according to the comparative size of the cells in the centre and circumference of an axis. In young stems with large pith, the central cells are larger, and they diminish towards the circumference ; whereas in roots, according to him, the diminution takes place in the reverse manner. Large cells distend more rapidly than small ones; and, according to their position in the axis, will Fig. 625. Fig. 625. Germination of the dicotyledonous aperispermic seed of Acacia Julibrissin. e, Spermoderm or testa. 1, Radicle of the embryo. ¢, Tigellus or cauliculus. ¢, Cotyledons. g, Gemmule or plumule. 1, First stage: in which the radicle ruptures the envelope or spermoderm, and appears externally at the micropyle. 2, Second stage: where the parts of the embryo are further disengaged from the covering, the summit of the cotyledons only being retained by the spermoderm. 3, Third stage: where the embryo is entirely dis- engaged from the envelope or spermoderm, and the cotyledons, cc, are séparated so as to exhibit the plumule, g. DIRECTION OF PLUMULE AND RADICLE. “353 thus cause curvature outwards or inwards, the largest occupying the convexity of the arch, the smallest the concavity. When a branch or root is laid horizontally, the force of endosmose is weakened on the lower side, and, consequently, will cease to neutralise the tendency to incurvation on the upper side, which will therefore be directed either upwards or downwards, according to the position of its layers of small cells,—in the case of a branch with large central cells, curving upwards ; and in the case of a root with larger hemispherical cells, downwards. These explanations do not appear, however, to be altogether satisfactory. It is known that the stem is directed upwards, the root downwards, but, as yet, physiologists have not been able to ascertain the laws which regulate them. The tendencies of the root and stem are not easily counteracted. When a seed is planted in moist earth, and suspended in the air, the root will, in the progress of growth, leave the earth and descend into the air in a perpendicular direction, while the stem will pass through a quantity of moist earth in an up- ward direction. If their positions are reversed they will become twisted, so as to recover their natural positions. Henfrey remarks that ‘so far as we are in a position to tell, there is some definite, and as yet unknown, cause which makes the radicle first grow towards the earth or other source of nourishment, which it penetrates by elonga- tion, a resisting point being offered by the weight of the seed or the earth covering it; and then, in its further growth downward, it requires a point of resistance to be afforded by the adhesion of the earth around the collar, ring, or neck of the root, since the elongation takes place in the structures just above the point of the root, thus exerting a pressure upwards and downwards, which if the upper part of the root be kept free, and the weight of the plant balanced, will cause the whole to rise bodily upwards. Thus, when seeds germinate in damp moss lying upon a hard surface, the elongation of the root will push the stem up through the moss, unless the root branches so as to get fixed down by entanglement among the loose matter. We may admit, therefore, that we are at present totally ignorant of the cause of the direction taken by roots. All the notions hitherto advanced having been purely speculative.” The effect of light on the stem may be illustrated by the growth of plants in circumstances where a pencil of light only is admitted on one, side. Dr.-Poggioli of Bologna was the first who observed the influence exercised by the rays of the spectrum in causing flection of plants.. Experiments on this subject have been made by Payen, Dutrochet, and Gardner. They consider the blue rays as those which have the greatest effect on the plumule. Hunter observed, that if a barrel filled-with earth, in the centre of which are some beans, was rotated for several days horizontally, the roots pointed in a direction 2A 354 MONOCOTYLEDONOUS GERMINATION. parallel to the axis of rotation. Knight* put Mustard seeds and French beans on the circumference of two wheels, which were put in rapid motion, the one in a horizontal, and the other in a vertical manner ; and he found that in the former the roots took a direction intermediate between that impressed by gravitation and by the centri- fugal force—viz., downwards and outwards, while the stems were inclined upwards and inwards, In the latter, where the force of gravitation was neutralised by the constant change of position, the centrifugal force acted alone, by which the roots were directed out- wards, at the same time that the stem grew inwards. To explain these results, there must be allowed—1. A more or less liquid con- dition of the new parts of the young plant. 2. A different density in the different parts of the latter. 3. A tendency of the denser parts of new plants, during germination, towards the root. On the vertical wheel, the parts of the young plants submitted to the centrifugal force only, had their roots or densest parts at the circumference. On the horizontal wheel the effect was intermediate between centrifugal force and gravity. The upper side of leaves is under the influence of light in a marked degree, for, when placed in the reverse position by the turning of a branch, they twist round so as to resume their natural exposure. During darkness, on the contrary, many leaves fold in such a way that their lower surface is exposed. Some plants grow indifferently in all directions at the period of germination. The Mistleto and other parasites direct their radicles towards the centre of the plants to which they are attached, while the plumule grows perpendicularly to the surface. MonocoryLeponovus GERMINATION.—In Monocotyledons there is generally a perisperm present, often in large quantity, and in them the cotyledon remains more or less within the seed at the period of germination, The intra-seminal portion of the cotyledons, as in Canna (fig. 626), and especially in the Coco-nut, becomes developed as a pale cellular mass, which increases much, and absorbs the nutri- ment required for the embryo. In some Monocotyledons the perisperm disappears entirely ; in others, as in the Phytelephas or Ivory Palm, while certain soluble matters are removed, the perisperm still retains its original form. The intra-seminal part may be said to correspond to the limb or lamina of the cotyledonary leaf. The extra-seminal portion, corresponding to the petiole, becomes often much elongated, ‘as in the double Coco-nut, and ends in a sheath which envelopes the axis or cauliculus, and the plumule. Sometimes, however, there is no marked elongation of the cotyledon, the sheath being at once formed on the outside of the seed, so that the plumule and radicle are, as it were, sessile on its surface. These phenomena are well seen in Canna indica (fig. 626), where ¢ is the envelope of the seed; p, the peri- * See Knight’s Horticultural Papers, London, 1841, p. 124. MONOCOTYLEDONOUS GERMINATION. 3905 sperm or albumen ; ¢, the intra-seminal portion of the cotyledon, which absorbs the nourishment ; p c, the petiolary or extra-seminal portion of the cotyledon, which varies in length, and may be wanting ; », the sheathing portion of the cotyledon, from a slit in which, f, the plu- mule, g, protrudes, supported on the axis or cauliculus, ¢; while the Fig. 626. radicles, r and 7’, pierce the integument at the base, and are each covered with a separate sheath, co, called coleorhiza (fig. 105, p. 42). In aperispermic Monocotyledons, as Alismaceze and Potamese (fig. 595, p. 334), the cotyledon does not remain within the seed, but is raised above the ground, ¢, giving origin to the plumule, g, which is at first enclosed in its sheath. Thus the cotyledon follows the development of leaves. Its limb is first produced, and is either pushed above ground, or is confined within the seed. In the latter case it is arrested in its progress; subsequently, a sheath is formed which may either be a direct continuation of the limb, or may be separated from it by a petiolary portion. When the limb is confined in the seed, and ceases to be developed, the sheath often continues to grow, forming a marked covering of the axis. The rootlets in Monocotyledons during germination (fig. 105 rr, p. 42) pierce the radicular extremity of the embryo, and become covered with sheaths or coleorhizas, ¢ c, formed by a superficial layer of cellular tissue. As the radicular extremity Fig. 626. Germination of the monocotyledonous perispermic seed of Canna indica. The seed is cut to show the relation between the perisperm and the embryo at different stages, the former diminishing, while the latter increases. e, Envelope or spermoderm. 0, Its upper part, which is separated like a lid or operculum, to allow the passage of the radicle. , Perisperm or albumen. ¢, Cotyledon. 7, Radicle or young root. 7 7’, Secondary radicles. co, Coleorhiza or sheath of the roots. /f, Slit indicating the position of the gem- mule ; at this slit an elongated sheath, v, is protruded. oc, Narrow portion of the cotyle- don (corresponding to the petiolary portion), intermediate between its enlarged portion, ¢ (corresponding to the lamina or limb of the leaf), and its sheathing or vaginal portion, v. t, Tigellus or cauliculus. g, Gemmule or plumule. 1, First stage, in which the radicle, r, begins to appear through the integuments or spermoderm. 2, Second stage, where the slit, J, is seen also on the outer surface, indicating the situation of the gemmule. The true radicle, 7, has pierced the envelope of the seed, and at its base shows a small sheath or coleorhiza. One of the small radicles, 7’, is also seen with a coleorhiza, 38, Third stage, when all the parts are more developed, and the gemmule, g, appears on the outside of the slit, f, the edges of which are prolonged in the form of a sheath or vagina, v. 356 DICOTYLEDONOUS GERMINATION. thus remains within the embryo, and sends out radicles (adventitious or secondary rootlets) from its surface, the plants are said to be endo- rhizal (evdov, within, ¢/Za, a root). See page 42. DicoryLeponous GERMINATION.—In Dicotyledons, the cotyledons generally separate from the integuments, and either appear above ground in the form of temporary leaves (figs. 627, 628 cc), which differ in form from the permanent leaves of the plant (fig. 628 g), or remain below as fleshy lobes. In the former case they are epigeal (éa7, Fig. 628. 1 ER $03) i FF % \3 & Fig. 627. Fig. 629. upon or above, yéa, 7%, the earth), in the latter case (as in Beans, Arachis, etc.), they are hypogeal (bxé, under). The cotyledons usually separate, but sometimes they are united, and appear as one. In all cases, the plumule (figs. 627, 628 g) proceeds from between the two cotyledons, and does not pierce through a sheath as in monocotyle- Fig. 627. Germination of the dicotyledonous embryo of Acer Negundo. m, Collum, collar or neck. 7, Root. t, Caulicule or stem. cc, Cotyledous. g, Gemmule or plumule. Fig. 628. Upper part of the same embryo more developed. cc, Cotyledons. g, Gemmule, the first leaves of which are already expanded. ¢, Caulicule or stem. Fig. 629. Acotyle- donous embryos or spores of Marchantia polymorpha, germinating. 1, Spore in the early stage of germination. 2, Ina more advanced stage. The spores are simple cells, which elongate during germination at some point of their surface. They are heterorhizal. They may be compared to naked embryos rather than to seeds, ACOTYLEDONOUS GERMINATION. 357 dons. The root (fig. 627 r) is a direct prolongation of the axis, ¢, in a downward direction, separating from it at the collar, m, and the embryo is here exorhizal (2&w, outwards), See page 41. ACOTYLEDONOUS GzRMINATION.—In Acotyledons the spore (fig. 629) has no separate embryo in its interior. It may be considered rather as a cellular embryo than a seed. It germinates by sending off cellular root-like prolongations from all parts of its surface, hence it is called Aeterorhizal (repos, diverse) (see p. 43). These cellular processes may be formed either from the entire wall of the spore or from its inner covering. In fungi the spore gives origin to a cellular axis called spawn (mycelium), on which ultimately the fructification is developed. The spores of Fungi often germinate in anomalous posi- tions, such as the organs of other plants, and the bodies of animals and man. Much injury is often occasioned in crops by the attacks of these spores. In the higher acotyledons the spores form in the first instance a cellular prothallus, in which the organs of reproduction ultimately are developed (see p. 279). In speaking of the germination of Hypho- mycetous Fungi, Lister states that these spores (conidia) germinate in three ways. 1. They may form their sprouts, which become plants like the parent. 2. They may multiply by pullulation, like the yeast plant, and, under some circumstances, this toruloid growth may continue for an indefinite period, though the resulting progeny will, under favouring conditions, reproduce a fungus like the original. 3. The conidia may shoot out sprouts of exquisite delicacy, which break up into Bacteria. These Bacteria, like the fungi whence they are derived, are of various totally distinct kinds, both morphologically and physiologically. They give rise to different fermentative changes, and some refuse to grow in media in which others thrive. Bacteria cannot be classified merely by forms, we must take into account their physiological peculiarities. Some seeds commence the process of germination before being de- tached from the plant. This occurs in a remarkable degree in the Mangrove tree, Rhizophora Mangle, which grows at the muddy mouths of rivers in warm climates. Coco-nuts often begin to germinate during a voyage from the tropics to Britain, and germinating seeds have been found in the interior of Gourds, as well as in the fruit of Carica Papaya, the Papaw. The seeds of the Banyan, or Bo-tree (Ficus indica), seldom ‘ germinate on the ground. The fig-like fruit of the tree is eaten by birds, and the seeds are deposited in the crown of Palms, where they grow, sending down roots which embrace and generally kill the Palm. ProiFerous PLants.—In place of seeds, some plants produce buds, which can be detached, and produce separate individuals. Flowers which are thus changed into separable buds are called prolifer- ous (proles, offspring, and fero, I bear), or viviparous (vivus, alive, and pario, I produce). They are met with in many alpine grasses, as 358 PROLIFEROUS OR VIVIPAROUS PLANTS. Festuca ovina, var. vivipara, Aira ceespitosa, var. alpina, Poa alpina, etc., as well as in Alliums, Trifoliums, and Ferns. Buds of a similar kind may be produced on the edges, or in the axil of leaves, as in Bryophyllum calycinum, Malaxis paludosa (fig. 231, p. 118), many species of Gesnera, Gloxinia, and Achimenes ; and the bulbils of Lilium (fig. 230, p. 117), Ixia, Dentaria, Ornithogalum (fig. 232, p. 118), some Saxifrages (S. cernua and §. foliolosa), seem to be peculiar forms of buds, capable of being detached, and of assuming indepen- dent growth. Buds, however, differ from true embryos in the direction of the roots being towards the axis of the plant. In uni- cellular plants, and others of the lowest class, it is common to find each cell possessing the power of producing a new individual, either by simple division or by the formation of a'cellular bud. In higher plants this mode of propagation is carried out by means of an assem- blage of cells, which are developed into an organ or bud of a more complicated nature, before it is detached. Multiplication by division of cells is very common among the lowest Alge, such as Desmidiacese and Diatomacez (fig. 472, p. 267). In the case of Lichens, the thallus produces gonidia (p. 269), which appear to be a collection of cellular buds capable of producing independent individuals. On the thallus of Liverworts (Marchantia) cup-like bodies are produced con- taining gemme (fig. 488 g, p.275). In Mosses the power of repro- duction by gemme is very marked. Almost every cell of the surface of Mosses, according to Schimper, is capable of giving origin to a leafy plant .or innovation. Ferns are propagated by buds, and gemma occasionally occur on their prothallium. The higher classes of plants may be considered as consisting of numerous buds united on a common axis (fig. 219, p.109). These possess a certain amount of independent vitality, and they may be, separated from the parent stem in such a way as to give origin to new individuals. In some instances buds are produced which are detached spontaneously at a certain period of a plant’s life. The cloves formed in the axils of the scales of bulbs are gemme or buds, which can be detached so as to form new plants. The length of time required for the protrusion of the radicle varies in different plants. Some seeds, as garden cresses, germinate in the course of twenty-four hours, others require many days or many months. Seeds with hard coverings, or a stony perisperm, may lie dormant in the soil for a year or more. The following experiments were made in the Geneva garden, on seeds similarly watered, and exposed to a medium temperature of 53° F. It was ascertained that one-half of the species of the following families germinated after the lapee of the number of days here mentioned :— Amarantacese - - si % . ‘ ‘ 7 9 days. Crucifere 10 ,, Boraginacee, Car. yophyllaces, Chenopodiaces, Malvacess a U5, DURATION OF THE LIFE OF PLANTS. 359 Composite, Convolvulacez, Plantaginacee a 12 days. Polygonacee . 5‘ ‘ C 5 13) 55 Campanulacez, Leguminosee, Valerianacez - 3 si 14 ,, Graminex, Labiate, Solanacez 2 a ; . LB Ge Rosaces ‘ * r 4 a : ‘ ‘ : Tw Ranunculacese ‘ i i 2 r ‘ ‘ 20 4 Antirrhinums, Onagr acess i ‘ i é ‘ ‘ 22 44 Umbelliferz . x i fi ‘ ‘ é ‘ ‘ 23 Temperature has a great effect in accelerating germination. Thus, Erigeron caucasicum, at a temperature varying from 49° to 53°, ger- minated in ten days; at a temperature from 66° to 72°, in two days ; Dolichos abyssinicus, at the former temperature, in ten days, at the latter, in three ; Zinnia coccinea, in twenty-two and five days respectively. Duration oF THE Lire oF Piants.—Plants, according to the duration of their existence, have been divided into annual, biennial, and perennial. * The first|of these terms imports that the seed ger- minates, and that the plant produces leaves and flowers, ripens its seed, and perishes within the year; the second, that a plant ger- minates and produces leaves the first year, but does not produce a flowering stem, nor ripen its seed, till the second, after which it perishes ; while the third intimates that the process of flowering and fruiting may be postponed till the third year, or any indefinite period. The first two exercise the function of flowering in general only once, while the last may do so several times before dying. Under different climates, however, and under different modes of management, the same species may be annual, biennial, or even perennial. Thus, Wheat in this country is annual if sown early in spring, but biennial if sown in autumn ; in hot climates Lolium perenne proves annual ; the Castor-oil plant in ‘this country is annual, while in Italy it is a shrub of several years’ duration ; the annual Mignonette, by removing its flower-buds the first year, and keeping it in a proper temperature during the winter, may be rendered perennial and shrubby. Many flowering garden plants, as Neapolitan Violet and Lily of the Valley, may be brought into flower at a late period of the year, by pinching off the blossoms in the early part of the season. Plants, as regards their flowering and fruiting, have also been divided into monocarpic (u6vos, one, and xaprds, fruit), or those which flower once only and then die ; and polycarpic (woAts, many), or those which flower and fruit several times before the entire plant dies. Thus, annuals and biennials, which flower the first or second year and die, as well as the Agave, and some Palms which flower only once in forty or fifty years, and perish, are monocarpic; while perennials are polycarpic. Some perennial woody plants live to a great age. The Baobab of Senegal, the Wellingtonia, the Dragon-tree, the Yew, the Oak, the Lime, the Cypress, the Eucalyptus, the Olive, the Orange, Banyan, and Chestnut, often attain great longevity. i 360 DURATION OF THE LIFE OF PLANTS. The following is a notice of the size and age of some trees :— Height to which forest trees grow in France . . 120 to 180 feet. Height to which forest trees grow in America . i 150 to 250 ,, Height of specimens of Wellingtonia (Sequoia) gigantea . 450 ,, Trunks of some Baobabs (Adansonia) have a girth of . . 90, Trunk of Dragon-tree (Dracena) of the Canaries hasagirthof 465 ,, That of a Maple (Acer) in South Carolina hasa girthof . 62 ,, In France trees have often a girth of . 7 . . 25 to 30 Oaks in Britain planted before the pe ea more than - 800 years old, Yew at Fountains Abbey, Ripon . é 3 . 1200 =—,, Yews in churchyard of Crowhurst, Surrey . ‘ 1450S, Yew at Fortingal, Perthshire . 7 - " upwards of 2000 a Yew at Hedsor, Bucks . ‘ 7 ‘ : é . 8200, A specimen of the Banyan (Ficus indica), which grew till recently on an island in the river Nerbudda, was believed to be identical with one that existed in the time of Alexander the Great, and which, according to Nearchus, was then capable of overshadowing 10,000 men. The chief trunks of this tree greatly exceeded our English Oaks and Elms in thickness, and were above 350 in number. The smaller stems were more than 3000 in number. The Maronites believe that some Cedars near the village of Eden in Lebanon are the remains of the forest which furnished Solomon with timber for the temple, full 3000 years ago. They must be of great antiquity, seeing they were counted old 300 years ago. Maundrell mentions the size of some of the Cedars. The largest he measured was 36 feet 6 inches in circum- ference, and 117 feet in the spread of its boughs. Decandolle has given a list of the ascertained ages of certain trees :— Elm. : é : ‘ 3 é ; . 885 years. Cypress, about . 4 ‘ ; ‘i = 1900) 3, Cheirostemon (Hand- tree), about . ‘ ” é 400 ,, Ivy. 7 : ‘ 4 % i i . 450 ,, Larch .. “ i i i . be IDLE. yy Sweet Chestnut, about ‘ x é‘ ‘ » 600 ,, Orange . j . f ‘ ‘i F - 630 ,, Olive . : z . 700 ,, Platanus orientalis (oriental Plane) . 5 = A205 Cedar . . 800 ,, Many tropical trees, according to Humboldt, ahout . 1000 ,, Wellingtonia, according to Torrey ¥ . % ee ALZO 55 Lime , 2 . i 4 i , . 1076, 1147 ,, ‘Oak ‘ ‘ ¥ 3 é . 810, 1080, 1500 ,, Yew _ . ‘ “1214, 1458, 2588, 2820 ,, reapen ee as old as the Yew. Decandolle states that the Yew increases little more than one line in diameter annually, during the first hundred and fifty years, and a little more than one line afterwards, and in very old specimens he con- DURATION ,OF THE LIFE OF PLANTS. 361 siders their age to be at least equal to the number of lines in their diameter. This average, however, is probably too high for young trees, and too low for old ones. In 1836, Mr. Bowman measured the trunks of eighteen Yews in the churchyard of Gresford, near Wrex- ham, in North Wales, which were planted out in 1726, and found their average diameter to be 20 inches, or 240 lines. Comparing them with the dimensions of other trees whose ages are known, he came to the conclusion, that for Yews of moderate age, and where the circumference is less than 6 feet, at least two lines, or of an inch of their diameter, should be allowed for annual increase, and even three lines or more if growing in favourable circumstances. He states that a, Yew in the same churchyard, whose mean diameter is 8 feet 6 inches, or 1224 lines, and whose age, by Decandolle’s method, would be as many years, was in reality 1419 years old. Sections taken from different sides of the trunk contained as follows :— Average number of annual rings per inch, SS 1 oe oe P ; counted on the horizontal plane. (Oui this. sotth=west aide 15 giving a general average of 342 rings in an inch of the diameter. Supposing that this tree, when 150 years old, had a diameter equal to that of the eighteen already mentioned, and among which it grows, and had continued to increase in the same ratio up to 150 years, and also making additional allowance for an intermediate rate of increase between 150 and 250 years, Mr. Bowman arrives at the following result :—At 150 years old, its diameter would be 25 inches; at 246 years old, 33 inches, leaving 5 feet 9 inches of the diameter for subse- quent increase, the radius of which, at 34 rings to the inch, would contain 1173 rings, or years of growth; to this add 246, and its present age would be 1419 years. — Another Yew in Darley churchyard, Derbyshire, is mentioned by Mr. Bowman, in which sections taken from its north and south sides gave 44 annual rings in the inch, so that its radius would contain 286 such rings, supposing them to be of equal thickness throughout, but making the same deductions as before, its present age may be esti- mated at about 2006 years. This examination shows the Gresford Yew to be about 200, and that at Darley about 650 years older than Decandolle’s standard of one line per annum of the diameter would indicate, and consequently, that for old trees his average is too low. It also shows that the Darley tree, with a greater diameter than the other of only 11 inches, is 587 years older, the excess arising from the extreme thinness of its annual deposits. No precise rule can there- fore be laid down, and actual sections must he resorted to if anything like accuracy be required. 362 VEGETABLE METAMORPHOSES. 10.—General Observations on the Organs of Plants, and on the Mode in which they are arranged. Plants may be said to be composed of numerous individuals, each having a sort of independent existence, and all contributing to the general growth of the compound individual formed by their union. In the case of a tree there are a vast number of buds, each of which is capable of being removed, and of being made to grow on another tree by grafting ; and although each has thus a vitality of its own, it is nevertheless dependent on the general vitality of the tree, so long as _ , it is attached to it. The same thing is seen in Sertularian Zoophytes. Each of the individuals forming a compound plant is called by Gaudi- chaud a phyton (purov, a plant), and in it he recognises three parts or merithalli (wéeos, a part, and daAAés, a young shoot), the radicular merithal corresponding to the root, the cauline to the stem, and the foliar to the leaf. In Acotyledonous plants the embryo or spore consists of united cells, and it is only after germination that it exhibits these different parts. In Monocotyledons, the embryo consists of a single phyton, with a radicular merithal or radicle, a cauline or tigellus, and a foliar or cotyledon. In Dicotyledons the embryo consists of two or more phytons united, with their foliar merithals (cotyledons) distinct, while their cauline and radicular merithals form each a single organ, In tracing the various parts of plants, it has been shown that all may be referred to the leaf as a type. This morphological law was propounded by Linneeus and Wolff, but it is to Goethe we owe the full enunciation of it. Vegetable morphology, the study of forms, or the reference of the forms of the parts of plants to the leaf, is now the basis of organography, and it will be observed that in considering the various organs this has been kept constantly in view. The calyx, corolla, stamens, and pistil, are only modifications of the leaf adapted for peculiar functions. It is not meant that they were originally leaves, and were afterwards transformed ; but that they are formed of the same elements, and arranged upon the same plan, and that in the changes which they undergo, and the relation which they bear to each other, they follow the same laws as leaves do. The different parts of the flower may be changed into each other, as into true leaves ; or, in other words, the cellular papille from which they are formed are capable of being developed in different ways, according to laws which are still unknown. These changes may take place from without inwards, by an ascending or direct metamorphosis, as in the case of petals becoming stamens; or from within outwards, by descending or retrograde metamorphosis, as when stamens become petals, Bracts are very evidently allied to leaves, both in their colour and SYMMETRY OF ORGANS. 363 form. Like leaves, too, they produce buds in their axil. ~The mon- strosity called Hen and Chickens Daisy depends on the development of buds in the axil of the leaves of the involucre. The sepals frequently present the appearance of true leaves, as in the Rose. The petals sometimes become green like leaves, as in a variety of Ranunculus Philonotis mentioned. by Decandolle, and in a variety of Campanula rapunculoides noticed by Dumas. At other times they are changed into stamens. Decandolle mentions a variety of Capsella Bursa-pastoris, in which there were ten stamens produced in conse- quence of a transformation of petals. The stamens in double flowers are changed into petals, and in Nymphea alba there is a gradual transition from the one to the other. Sometimes the stamens are changed into carpels, and bear ovules. This has been seen in Wall- flower, some Willows, Poppy, etc. Petit-Thouars noticed a plant of House-leek, in which the one-half of the anthers bore ovules, and the other half pollen. The carpels, as in the double Cherry, may be seen in the form of folded leaves ; in double flowers they are transformed into petals, and in other cases they are developed as stamens. In a monstrosity of Wallflower the placenta gave origin to flowers. It is said that increase of temperature and luxuriance of growth sometimes make flowers produce stamens only. In plants having unisexual flowers this is more liable to take place, as in Melon, Cucumber, etc. Increased vigour seems to be required for the development of stamens. Some fir trees in their young state bear cones, and produce male flowers only when they reach the prime of life. ‘ “ SymueTry or Orcans.—In the progress of growth the plants belonging to the different divisions of the vegetable kingdom follow certain organogenic laws (éeyvé&vov, an organ, and yewdéw, I produce), the operation of which is seen in the definite arrangement of their organs. The flower consists sometimes of three, at other times of four or five equal sets of organs, similarly and regularly disposed. Thus, the Iris has three straight parts of its perianth, and three reflexed ones alternately disposed, while the Fuchsia has four parts of the calyx alternating with four petals, and the Rose has five alternat- ing portions. This orderly and similar distribution of a certain number of parts is called symmetry, and flowers are thus said to be symmetrical with various numbers of members. When the number of parts is two the flower is dimerous.(d/c, twice, wégos, a part) (fig. 630), and the symmetry two-membered. ‘When the number of parts is three the flower is trimerous (rge%, three), and when the parts are arranged in an alternating manner (fig. 631) the symmetry is trigonal or triangular (ree, three, ywvic, an angle), as in the Lily. When there are four parts the flower is tetramerous (rergds, four), and the symmetry is tetragonal or square (figs. 632, 633), as in Galium and Paris. When there are five parts the flower is pentamerous 364 SYMMETRY OF ORGANS. (wévre, five), and the symmetry pentagonal (fig. 634), as in Ranun- culus. The number of parts in the flower is indicated by the following symbols :—Dimerous 2/, Trimerous %/, Tetramerous ogy TT “ey hydouy ‘T. ~epkqdount0g x x “‘VLILHAOUSLSAH ‘II “‘VIZHAOLOU I { oh Colley « “RIOPLULTRYL, “T ( ** exoprosTey oJ ‘SHNOGHT -ALOODIGA *'BLOPILOION “g ses gapsur ~e[OUOW! 'F ‘euaSoxy *a souopetsyoorq + + ‘Il’ 'WAVSOUANVHd “NOW ‘TIT’ *'’ WNVNOLIAYO ‘NOW ‘wuaSopug ‘a seuopetsyooouoyy + “RoWopa[s4ON ‘a SaIVMISBA « x eweSOroy { ‘AT SNOT “BIALOOV eeypsyde { ‘watope [soo “@ Sare[NTTIO x Cayoped-) { -od sq ed -1da gas! te -wed -odsy, (aouvwnjs-) { (‘wusadsorbun-) \(‘armuadsowwhB-) ‘wudsited- ‘wudside- -eudsoday- (‘g ‘seorTy) Cg ‘eorqeda (+ ‘Yosnut, CT 8anj) “saUudyor] (3 ‘eesiz) -od Aq, -yod -1da j \ (owow) 8L rt} wreyodAod ¢ SL ‘mua ee 11} “an.ayy oo z { { \ ~UDS109 “6 8 4 9 } epeyody T ¢ gI { © \-sanoaat & (-KLOOONON ‘II ‘SUNOGHTALOOIC TI Sore[NSadit F SOUT, vreseeeres™""T SHNOGHTALOOYV ‘I ‘OPS ‘AD TANI'T ‘OSST “UMHOIIGNE ‘GIS “HITOGNVO Fa “684T ‘AHISSAL ‘o[pUrT pue “Tey TpUA “oyopueg oq ‘norssng jo smot,A oemMoyshg oy} Jo uostreduog oyeutrxoadde s,mojsuey NATURAL ARRANGEMENT OF HOOKER. 423 The following is Dr. Hooker's synopsis of classes, sub-classes, and cohorts :— Sus-Kinepom I,—Puanogamovs, CoTYLEDONOUS, OR FLOWERING PLANTS. Class I. Dicotyledons. Sub-class I. Angiospermous. Ovules produced in a closed ovary, fertilised by the pollen-tube tra- versing a stigmatic tissue to-reach the cavity of the ovary, and hence the embryo-sac of the ovule. Division "I. Polypetalous. Flowers with both a calyx and a corolla, the latter of separate petals. Series I. Thalamifloral. Sepals usually distinct and separate, free from the ovary. Petals 1-2- co-seriate, hypogynous. Stamens hypogynous, rarely inserted on a short or long torus, or on a disk. Ovary superior. Cohorts.—1, Ranales ; 2, Parietales ; 3, Polygalales ; 4, Caryophyllales ; 5, Guttiferales ; 6, Malvales, Series II. Discifloral. Sepals distinct or connate, free or adnate to the ovary. Disk usually conspicuous, as a ring or cushion, or spread over the base of the calyx-tube, or confluent with the base of the ovary, or broken up into glands. Stamens usually definite, inserted upon or at the outer or inner base of the disk. Ovary superior. Cohorts.—7, Geraniales ; 8, Olacales; 9, Celastrales ; 10, Sapindales. Series III. Calycifloral. Sepals connate (rarely free), often adnate to the ovary. Petals 1- seriate, perigynous or epigynous. Disk adnate to the base of the calyx, rarely tumid or raised into a torus or gynophore. Stamens perigynous, usually inserted on or beneath the outer margin of the disk. Ovary frequently inferior. Cohorts.—11, Rosales ; 12, Myrtales ; 18, Passiflorales ; 14, Ficoidales ; 15, Umbellales. Division II. Monopetalous. Flowers furnished with both sepals and petals, the latter connate. Series I. Epigynous. Ovary inferior. Cohorts.— 16, Caprifoliales ; 17, Asterales ; 18, Campanales. Series II. Hypogynous or Perigynous. Ovary superior. Cohorts.—19, Ericales; 20, Primulales; 21, Hbenales ; 22, Gentian- ales ; 28, Polemoniales ; 24, Solanales ; 25, Personales ; 26, Lamiales. Division III. Apetalous or incomplete-flowered. Flowers with a single floral envelope (the calyx) or none. Subdivision I. Ovary superior—perianth usually distinct. Cohorts——27, Chenopodiales; 28, Laurales; 29, Daphnales ; 30, Urticales ; 31, Amentales ; 32, Euphorbiales ; 33, Piperales,; 34, Nepenthales. 424 NATURAL SYSTEM IN MANUAL. Subdivision II. Ovary inferior —Perianth more or less distinct in the 6, or ?, or both. : Cohorts. —35, Asarales ; 36, Quernales ; 37, Santalales. Sub-class II. Gymnospermous. Ovules produced superficially on a scale (bract or open ovary) ; ferti- lised by the direct application of the pollen to the apex of the nucleus, which the pollen-tube penetrates. Flowers unisexual (except in Welwitschia.) Class II. Monocotyledons. Division I. Ovary inferior —Perianth usually distinct; 2-seriate and coloured, Cohorts.—1, Hydrales ; 2, Amomales; 3, Orchidales; 4, Taccales ; 5, Narcissales ; 6, Dioscorales, Division IJ. Ovary superior. Subdivision I. Ovary apocarpous. Cohorts. —7, Triurales ; 8, Potamales. Subdivision II. Ovary syncarpous. Cohorts.—9, Palmales ; 10, Arales; 11, Liliales; 12, Pontederales ; 13, Commelynales ; 14, Restiales ; 15, Glumales. Sus-Krinepom II.—Crryrtoaamous, ACOTYLEDONOUS, OR FLOWERLESS Puants. Class III. Acrogens. Cohorts. —1, Filicales ; 2, Muscales. Class IV. Thallogens. In the succeeding pages the natural orders will be grouped under the following divisions :— A. PHANEROGAMOUS, COTYLEDONOUS, OR FLOWERING PLANtTs. Class I. Dicotyledones or Exogene. Sub-class 1. Thalamiflore. ...Petals distinct, stamens hypogynous............ 2. Calyciflor ....... Petals distinct Polypetale of Jus- or united, stamens perigynous sieu, and Monopet. : i < Dichlamyden, OF CPIZYNOUS .....0.6..eeeeeerese Peri- and Epi-co- having calyx separate rolle. and corolla, —— 2. Gamopetale:... coherent. ——. 3. Corolliflore......... Petals united, . corolla hypogynous, usually Monopoly Ea bearing the stamens............. A i ——-— 4. Monochlamydez...A calyx only, Having a sin- OF MONG, ....seeeseseeeeeees eee Apetale and partly , gle perianth. l ee pe as seeds in a0 ¢ Diclines of Jussieu. 6. Gymnosperme, seeds naked. CHARACTERS OF CLASSES AND ORDERS. 425 Class II. Monocotyledones or Endogenz. Sub-class 1. Petaloidese or Floride, Floral envelopes verticillate. a. Hermaphrodite, ovary inferior. 6, Hermaphrodite, ovary superior. ¢. Unisexual, often achlamydeous. 2. Glumifere, Floral envelopes imbricated. B. CRYPTOGAMOUS, OR ACOTYLEDONOUS FLOWERLESS PLANTS. Class III. Acotyledones or Acrogene. Sub-class 1. Aitheogame or Cormogene...............ceeeeee Having vascular tissue. ——— 2. Amphigame, Thallogenz, or Cellulares......... Entirely cellular. CHAPTER II. ARRANGEMENT AND CHARACTERS OF THE CLASSES AND NATURAL ORDERS. Sug-Kinepom J.—PuHanerocamous Prants, Plants producing Stamens and Pistils, Crass I.—DIcoryLEDONES aND ExocEnas, Juss. and DC.; AcRaMPHIBRYA, Endl. This is the largest class in the vegetable kingdom. The plants included under it have a cellular and vascular system, the latter con- sisting partly of elastic spiral vessels, (Fig..51, p. 17). The stem is more or less conical, and exhibits wood and true bark. The wood is exogenous, %.¢, increases by additions at the periphery, the hardest part being internal (p. 49, et seq.). It is arranged in concentric circles. Pith exists in the centre, and from it diverge medullary rays. The bark is separable, and increases by additions on the inside. The epider- mis is furnished with stomata (p. 28). The leaves are reticulated (p. 84), usually articulated to the stem. The flowers are formed upon a quinary or quaternary type, and have stamens and pistils, The ovules are either enclosed in a pericarp, and fertilised by the applica- tion of the pollen to the stigma, or they are naked and fertilised by the direct action of the pollen. The embryo has two or more opposite cotyledons, and is exorhizal in germination (p. 41). Sub-class 1,—THALAMIFLORA.* Calyx and corolla present; petals distinct,t inserted into the * Thalamus, receptacle, and flos, flower. + Sometimes the petals are abortive, and it is then difficult to determine whether the plant belongs to this sub-class or to Monochlamydex. 426 RANUNCULACEA, thalamus (receptacle) ; stamens hypogynous. This includes the hypo- gynous polypetalous orders of Jussieu, and a diclinous order (Meni- spermacez.). Order 1.—RanuncuLacge&, the Crowfoot Family. (Polypetale Hypogyne.) Sepals 3-6, frequently 5, deciduous (fig. 663 ¢). Petals 5-15 (fig. 663 pe), rarely abortive, sometimes anomalous in form (fig, 308, p. 202), occasion- ally with scales at the base (fig. 662 a). Sta- mens usually indefinite, hypogynous (fig. 663 e) ; anthers adnate (figs. 665, 666) ; carpels numerous, l-celled (fig. 663 pi), distinct or united into a single many-celled pistil; ovary containing one : anatropal ovule (figs. 588, p. 332; 667 g), or Hig: 06h several united to the inner edge. Fruit various, either dry achzenia (figs. 559, p. 309 ; 668), or baccate, or follicular (figs. 539, p. 303; 564, p. 312). Seeds albuminous, erect, or pen- Fig. 668. Fig. 667. Fig. 666. Fig. 663. Fig. 665, dulous ; albumen, horny (fig. 668 p); embryo minute (fig. 668 e).— Herbaceous, suffruticose, or rarely shrubby plants, having alternate or opposite, simple, much-divided leaves, with dilated sheathing petioles (fig. 254, p. 176). Juice watery. Hairs, if present, simple. The plants of the order are found in cold damp climates, and in the elevated regions of warm countries. Europe contains one-fifth of the order, and North America about one-seventh. The order is divided into five tribes :—1. Clematidee ; 2, Anemones (fig. 268, p. Figs. 663-668 exhibit the organs of fructification of Ranunculus acris, to illustrate the natural order Ranunculacee. Fig. 663. Flower cut vertically. c, Calyx. pe, Petals. e, Stamens. yi, Pistil composed of several carpels on an elongated receptacle or axis. Fig. 664, Diagram of the flower, showing 5 imbricated sepals, 5 petals alternating with the sepals, indefinite stamens in several whorls, multiples of the petals, and numerous carpels or achenia in the centre. Fig. 665. Adnate anther seen on the outer side. The anther is in this instance extrorse. In Peonia and some other Ranunculacee it is introrse. Fig. 666. Adnate anther viewed on the inside. Fig. 667. Vertical section of the ovary, 0, showing the ovule, g. 8, Stigma. Fig. 668. Fruit, an achenium cut vertically. f, Peri- carp. t, Spermoderm or integument of the anatropal seed. p, Perisperm or albumen, between fleshy and horny. e, Minute embryo. RANUNCULACEAE. 427 181); Ranunculez (fig. 254, p. 176); 4. Hellebores (fig. 539, p. 303), 5. Peonie (fig. 404, p. 234), according to the estivation of the calyx, the nature of the fruit, etc. The following is an analysis of these sub-orders, with the number of British species in each :—~ Spec. Brit. Anther. Carpel, Seed. Aistiv. 1. Clematidee . . 1 ae * valvate Sanna 1g ( extomse { sperm, { Eoogmous meat. 4. Helleboree . . 10 polysperm. * * 5. Peonie . . . 1 _ introrse * * * Authors enumerate 32 known genera, comprising 1290 species. Ex- amples of the genera—Clematis, Anemone, Ranunculus, Helleborus, Aquilegia (fig. 309, p. 202), Delphinium, Aconitum, Actzea, Pzeonia, Podophyllum. The order has narcotico-acrid properties, and the plants are usually more or less poisonous. The acridity is frequently volatile, and disappears when the plants are dried or heated. It varies in different parts of the plants, and at different seasons. Ranunculus (the genus whence the order is named) contains many acrid species, such as R. sceleratus, alpestris, bulbosus (fig. 254, p. 176), gramineus, acris, and Flammula ; while others, such as R. repens, aqguatilis, Lingua, and Ficaria, are bland. The acridity is entirely lost by drying, and it disappears in the pericarps as the seeds (which are themselves bland) ripen. The leaves of Aconitum Napellus, Monkshood, Friar’s- cap, or Helmet-fiower (fig. 308, p. 202), contain a narcotic alkaloid, called aconitine. They are used as an anodyne in neuralgic affections, in the form of extract and tincture. The root or rhizome has some- times been mistaken for Horse-radish. The root of Aconitum ferox furnishes the powerful East Indian poison, called Bikh, Bish, or Nabee. The root or rhizome of Aconitum heterophyllum, atis or atees, is used as a remedy for intermittent fever in India. The leaves of Clematis recta and Flammula have been used as vesicants. The seeds of Delphinium Staphysagria, Stavesacre, are irritant and narcotic, and are used for destroying vermin. They owe their activity to an alkaloid principle, called delphinia. Delphinium glaciale grows at the height of 16,000 feet on the Himalayas. The Hellebores have been long noted for their irritant qualities. Helleborus officinalis, niger (Christmas-rose), fetidus, and viridis, act as drastic purgatives ; hence the use of some of them in ancient times in cases of mania. Actwa, spicata, baneberry, has a single succulent carpel, containing many ovules. The rhizome has some resemblance to that of black Hellebore. The fruit is poisonous. The rhizome of Actwa (Cimicifuga) racemosa, black ‘snake-root, black ‘cohosh or bugbane, is used in rheumatic affections. The rhizome of Coptis Teete is used in India as a bitter tonic, Wigella sativa is supposed to be the fitches of Scripture (nyp, 428 DILLENIACEZ—MAGNOLIACEZ. ketzach), called also black cummin and Fennel-flower. The roots of Hydrastis canadensis, yellow-root, are used as a tonic. The rhizome of Podophyllum peltatum, May-apple, is employed in America as a purgative. Some of the Ranunculacee are chiefly marked by bitter tonic properties. This order, in the position, number, and structure of its parts of fructification generally, presents a resemblance to several widely differing families. It differs from Dilleniacee in the want of an aril, in its deciduous calyx, and in its whole habit; from Magno- liacez, in the want of true stipules; from Papaveracee and Nympheacex, in the distinct not united carpels, watery not milky juice, and acrid properties. It closely approaches the Berberidacez, especially in Podophyllum (which some authors look upon as a Ber- berid), but differs in its stamens not bursting by recurved valves. In its numerous carpels, floral divisions, and indefinite stamens, it agrees with the Rosacez, but differs in its stamens being hypogynous instead of perigynous, in the large quantity of albumen surrounding the minute embryo, in the want of true stipules, and in its acrid pro- perties. Crowfoots and Umbellifers agree in some particulars; the latter, however, have their ovary inferior, and their stamens always definite. Order 2.—DiILLENIACEa, the Dillenia Family. (Polypet. Hypog.) Sepals 5, persistent. Petals 5, deciduous, in a single row. Stamens indefinite, hypogynous, either distinct or combined into bundles ; fila- ments dilated at the base or apex; anthers adnate, introrse, with longitudinal dehiscence. Ovaries definite, more or less distinct, with a terminal style and simple stigma; ovules anatropous. Fruit of 2-5 capsular or baccate unilocular carpels, which are either. distinct or coherent. Seeds erect or ascending, usually arillate, several in each carpel, or only two, or one by abortion ; testa crustaceous ; embryo straight, minute, axile, at the base of fleshy albumen—tThe plants of the order are trees, shrubs, or under-shrubs, having alternate, exstipulate, coriaceous, or rough leaves. They are found chiefly in Australia, Asia, and the warm parts of America. The Indian species are remarkable for their beauty, the grandeur of their foliage, and the magnificence of their flowers. They have astringent properties, and some of the species afford excellent timber. Authors enumerate 30 genera, including 230 species. Hxamples—Dillenia, Delima, Hib- bertia, Candollea, Tetracera. Order 3. —MAcNotiacea, the Magnolia Family. (Polypet. Hypog.) Sepals 2-6, usually deciduous. Petals 2-30, hypogynous ; often in several rows, Stamens indefinite, distinct, hypogynous; anthers adnate, long, dehiscing longitudinally. Carpels numerous, 1-celled, arranged upon a more or less elevated receptacle; ovules anatropal, suspended or ascending ; styles short. Fruit consisting of numerous distinct or partially coherent carpels, which are either dehiscent or ANONACEA, 429 indehiscent, sometimes samaroid. Seeds, when ripe, often hang sus- pended from the carpels by a long slender cord; embryo minute, at the base of a fleshy, not ruminate, perisperm.—Trees and shrubs, with alternate coriaceous leaves, and deciduous convolute stipules. They abound in North America, and species occur in India, South America, China, Japan, New Holland, and New Zealand. The order has been divided into—1. Winterez ; aromatic plants, in which the leaves are dotted, the carpels are in a single verticil, and the wood is often marked with punctations or dots. 2. Magnolies ; bitter plants with fragrant flowers, in which the carpels are arranged in several rows on an ele- vated receptacle (fig. 337, p. 213), and the leaves are not dotted. The Indian mountains and islands are the great centres of Magnolias. 3. Schizandreze ; usually climbing shrubs, with unisexual flowers, numer- ous baccate carpels, arranged-in heads or spikes, no stipules. Authors mention 10 or 12 known genera, comprising 70 species. Examples— Illicium, Drimys, Magnolia, Liriodendron, Schizandra, Trochodendron. The properties of the order are bitter, tonic, and often aromatic. Illicium anisatum, Star-anise, is so called from its carpels being arranged in a star-like manner, and having the taste and odour of anise. It is also called Badiane. Its fruit is employed as a carminative. Drymis Wintert or aromatica, brought by Captain Winter from the Straits of Magellan (Magulhaens) in 1578, yields Winter's bark, which has been employed medicinally as an aromatic stimulant. It somewhat re- sembles Canella bark. Magnolias are remarkable for their large odori- ferous flowers, and their tonic aromatic qualities. The bark of Mag- nolia glauca, Swamp Sassafras or Beaver-tree, is used as a substitute for Peruvian bark. The seeds of Magnolia Yulan, a species with deciduous leaves, are used in China as ajfebrifuge. Liriodendron tulipifera, the tulip-tree (fig. 337, p. 213), marked by its truncate leaves, has similar properties. Talawma fragrantissima supplies the Organ-nut of Brazil. Order 4.—ANnonacem#, the Custard Apple Family. (Polypet. Hypcg.) Sepals 3-4, persistent, often partially cohering. Petals 6, hypogynous, in two rows, coriaceous, with a valvate zstivation. Sta- mens indefinite (very rarely definite) on a large torus ; anthers adnate, extrorse, with a large 4-cornered connective. Carpels usually numerous, separate or cohering slightly, rarely definite; ovules ana- tropal, solitary or several, erect or ascending. Fruit succulent or dry, very rarely capsular, the carpels being one- or many-seeded, and either distinct or united into a fleshy mass; spermoderm brittle; embryo minute, at the base of a ruminated or motiled perisperm or albumen, which constitutes an important character of the order.—Trees or shrubs, with alternate, simple, exstipulate leaves, found usually in tropical countries. Authors enumerate 50 genera, including about 300 species. Examples—Bocagea, Anona, Uvaria, Guatteria, Xylopia, Duguetia, Asimina, 430 MENISPERMACEAI—BERBERIDACEA. Their properties are generally aromatic and fragrant. Some of the plants are bitter and tonic, others yield edible fruits. The cus- tard-apples, Sweetsops, and Soursops of the East and West Indies, are furnished by various species of Anona, such as A. muricata, squamosa, and reticulata. Anona Cherimolia furnishes the Cherimoyer, a well- known Peruvian fruit. The fruit of Yylopia aromatica is commonly called Ethiopian pepper, from being used as pepperin Africa. Xylopia glabra is called Bitter-wood in the West Indies. The Lancewood of coachmakers appears to be furnished by a plant belonging to this order, called by Schomburgk Duguetia quitarensis. Order 5.—M=ENIsPERMACEm, the Moon-seed Family. (Polypet. Hypog.) Flowers usually unisexual (often dicecious), generally of a pale-greenish hue. Sepals and petals similar in appearance, in two rows, usually 3 in each row, hypogynous, deciduous, Stamens mona- delphous, or occasionally free; anthers adnate, extrorse. Carpels solitary or numerous, distinct or partially coherent, unilocular ; ovule solitary, curved (fig. 456, p. 255). Fruita succulent 1-seeded oblique or lunate drupe. Embryo curved or perpherical; radicle superior ; albumen fleshy, sometimes wanting.—The plants of this order are sarmentaceous or twining shrubs, with alternate leaves, and very small flowers. The wood is frequently arranged in wedges. The order is common in the tropical parts of Asia and America. There are about 36 known genera, including about 300 species. Zzamples —Menispermum, Cissampelos, Cocculus. The species are bitter and narcotic. Some are employed as tonics, others have poisonous properties. The root of Jateorhiza palmata, a plant of east Africa, is known as Calumba-root, and is used as a pure bitter tonic in cases of dyspepsia, in the form of infusion or tincture. It contains a bitter crystallisable principle called Calumbin. Cocculus indicus is the fruit of Anamirta Cocculus, It is extremely bitter. The seed contains a crystalline poisonous narcotic principle, Picrotoxin, which is its active ingredient; while the pericarp yields a non- poisonous substance called Menispermin. The seeds have been used externally in some cutaneous affections. At one time they were employed, most prejudicially, to give bitterness to porter. Tinospora cordifolia, called Gulancha, is used as a tonic. The stem and root of Chondodendron tomentosum, found in Peru and Brazil, furnish Pareira- brava, which is tonic and diuretic, and is used in chronic inflammation of the bladder. Cissampelos ovalifolia and C. Mauritiana are tonic and diuretic. Cosciniwm (Menispermum) fenestratum supplies a false Calumba-root, which contains much Berberine, the same yellow bitter crystalline substance which is found in the Barberry. Order 6.—BERBERIDACEA, the Barberry Family. (Polypet. Hypog.) Sepals 3-4-6, deciduous, in a double row. Petals hypogynous, equal in number to the sepals, and opposite to them, or twice as many, NYMPHAACEA, 431 often having an appendage at the base on the inside. Stamens equal in number to the petals, and opposite to them; anthers adnate, bilocular (dithecal), each of the loculi opening by a valve from-the bottom to the top. Carpel solitary, unilocular, containing 2-12 ana- tropal ovules; style sometimes lateral; stigma orbicular. Fruit baccate or capsular, indehiscent. Albumen fleshy or horny; embryo straight, sometimes large (figs. 589, 590, p. 332).—Shrubs or her- baceous perennial plants, with alternate, compound, exstipulate leaves and flowers often in racemes (fig. 252, p. 175). The true leaves are often changed into spines, by non-development of parenchyma and induration of the veins (fig. 236 f, p. 119). Found chiefly in the mountainous parts of the temperate regions of the northern hemi- sphere. The plants of the order have bitter and acid properties. The bark and stem of Berberis vulgaris, common Barberry, are astringent, and yield a yellow dye and a crystalline matter called Berberine ; the fruit contains oxalic acid, and is used as a preserve. Berberis Lyciwm is used in India for ophthalmia. The genus Podophyllum is placed in this order by some botanists (see Ranunculacez). Lindley enume- rates 12 genera, including 109 species. Haxamples—Berberis, Mahonia, Epimedium, Diphylleia, Leontice, Lardizabala. Order 7.—NympH#AcEs, the Water-lily family (figs. 341, 342, p. 214; fig. 669). (Polypet. Hypog.) Sepals 3 to 5, sometimes con- founded with the petals. Petals numerous, often passing gradually into stamens (fig. 342, 2, p. 214), inserted at different heights in a torus. Stamens indefinite, inserted above the petals into the torus (fig. 669 c); filaments petaloid ; anthers adnate, introrse, opening by two longitudinal clefts, Torus large, fleshy, surrounding the ovary more or less (fig. 669 t). Ovary multilo- cular, many-seeded, with radiating stigmas (fig. 669 s) ; numerous ana- tropal ovules. Fruit many-celled, indehiscent. Seeds very numerous, attached to spongy dissepiments ; albumen farinaceous ; embryo small, enclosed in a fleshy vitellus, and situated at the base of the peri- sperm (fig. 576, p. 327).—Aquatic Fig. 669. plants, with peltate or cordate fleshy leaves, and a rootstock or stem ° which extends itself into the mud at the bottom of the water. There are 3 sub-orders :—1. Nymphe, water-lilies ; sepals 4-6, petals and Fig. 669.—Section of a flower of Nymphea alba, white Water-lily, showing the pistils, and the receptacle or torus bearing the stamens and petals. p, Peduncle or flower-stalk, t, Elevated torus or receptacle. s, Radiating stigmas. u, Sepal. 0. Petal. c, Stamens, 432 ‘ SARRACENIACE, stamens oo, carpels united, ovules ©, flowers large and showy. 2. Cabombex, water-shields ; sepals and petals 3, carpels few, placed in the torus, ovules three, flowers small. 3. Nelumbonez, water beans ; sepals 4-5, petals and stamens oo, carpels inserted in the top of a large flattened torus, ovules 1-2, seeds exalbuminous, flowers showy, and leaves rising above the water. Authors enumerate 8 genera, comprehending about 30 species. Zxamples—Nymphea, Nuphar, Victoria, Euryale, Cabomba, Hydropeltis, Nelumbium. Little is known in regard to the properties of the plants of this order. Some of them are astringent and bitter, while others are said to be sedative. They have usually showy flowers, and their petioles and peduncles contain numerous air-tubes. Victoria regia is one of the largest known aquatics. It-is found in the waters of South America, and is said to range over 35 degrees of longitude. The flowers have a fine odour. When expanded they are a foot in diameter. The leaves are from four to six and a half feet in diameter. The seeds and rootstocks of many plants of this order contain much starch, and are used for food. It has been said that the rhizomes of Nymphea alba are better than Oak-galls for dyeing grey ; they have been long employed advantageously for tanning leather. Nymphaea Lotus, Lotus Water Lily, is supposed by some to be thé lily (UW, sheshan or shushan) of the Old Testament. The stems of Nuphar lutewm, yellow pond lily, are reported to be astringent. Cabombez have peltate floating leaves ; some of them have astringent properties. The flower of Nelumbiwm speciosum is supposed to be the Lotus figured on Egyptian and Indian monuments, and the fruit is said to be the Pythagorean Bean (xicos). It is the sacred bean of India. The plant is said to have disappeared from the Nile, where it used to abound. The petioles and peduncles contain numerous spiral vessels, which have been used for wicks of candles. Dr. Wight states that those wicks on great and solemn occasions are burnt in the lamps of the Hindoos, placed before the ‘shrines of their gods. Nelumbium Leichardit is the sacred bean of N.E. Australia. Order 8.—SaRRACENIACEA, the Sidesaddle-flower, Water-pitcher, or Trumpet-leaf Family. (Polypet. Hypog.) Sepals 5, persistent, im- bricated in estivation, often with coherent bracts outside. Petals 5, hypogynous, concave ; occasionally the corolla is absent (Heliamphora), and the calyx consists of 4-6 segments. Stamens 00 ; anthers adnate, dithecal, introrse, with longitudinal dehiscence. Ovary free, tri- quinquelocular ; style single, sometimes dilated at the top into a 5- angled or 5-lobed parasol-like expansion, the deflexed points of which are stigmatiferous ; stigma persistent, sometimes truncated, at other times divided ; ovules anatropal. Capsule 3-5 celled, with loculicidal dehiscence. Seeds very numerous, small, attached to large placentas, which project from the axis into the cavity of the cells; albumen PAPAVERACEA. * 433 copious ; embryo cylindrical, lying at the base of the seed; radicle pointing to the hilum.—Herbaceous plants, found in boggy places, having radical leaves, the petioles of which are folded, and cohere at the edges, so as to form ascidia or hollow tubes, which are lined with hairs, and act as secreting organs (fig. 203, p. 96). Scapes one or more flowered. (See remarks on the physiology of these ascidia at p. 383.) The plants are found chiefly in North America. Darlingtonia grows on the Rocky Mountains, Heliamphora on Roraima Mountain in Venezuela, Their properties are not known. There are 3 genera, including 8 species. Examples—Sarracenia, Heliamphora, Darlingtonia. Order 9.—PapavERACEs, the Poppy Family. (Polypet. Hypog.) Sepals 2, rarely 3, caducous. Petals hypogynous, usually 4, cruciate, sometimes a multiple of 4, regular, rarely wanting. Stamens hypo- gynous, usually 00, sometimes a multiple of 4; anthers dithecal, in- nate. Ovary solitary ; style short or none; stigmas 2, or many and radiating (fig. 444, p. 249); ovules 00, anatropal (fig. 457, p. 256). Fruit unilocular, either siliqueform with two, or capsular with seve- ral parietal placentas. Seeds numerous ; albumen between fleshy and oily ; embryo minute, at the base of the albumen, with plano-convex cotyledons.—Herbs or shrubs, usually with milky or coloured juice, having alternate exstipulate leaves, and long one-flowered peduncles. The plants belonging to this order are chiefly European. The species, however, are found scattered over tropical America, Asia, China, Aus- tralia, Cape of Good Hope, etc. Lindley mentions 20 known genera, and 140 species. Examples—Papaver, Meconopsis, Esch- scholtzia, Sanguinaria, Glaucium, Chelidonium, Platystemon. The order possesses well-marked narcotic properties. Opium is the concrete milky juice procured from the nearly ripe capsules of Papaver somniferum, and its varieties. The plant is a native of Western Asia, and probably also of the south of Europe ; but it has been distributed over various countries. There are four kinds of opium known in commerce, viz. Turkey, Egyptian, East Indian, and Persian; of which the first is the kind chiefly used in Britain, The most im- portant active principle in opium is the alkaloid called morphia, There are other crystalline principles found in it, such as codeia, narcotine, thebaia, meconine, and an acid called meconic acid, which constitutes with sulphuric acid the solvent of the active principles. Opium is administered so as to act as a stimulant, a narcotic, ano- dyne, or diaphoretic. The seeds of the Opium Poppy yield a bland, wholesome oil. The petals of Papaver Rheas, red corn poppy, or corn-rose, are used in pharmacy chiefly for their colouring - matter. Chelidonium majus, Celandine, yields an orange-coloured juice, which is said to have acrid properties. In this plant, observations were made by Schultz on Cyclosis (fig. 241, p..146). Zschscholtzia is remarkable for the dilated apex of the peduncle, from which the 2F 434 . FUMARIACEAI—CRUCIFERA, calyx separates in the form of a calyptra, resembling an extinguisher of a candle. Sangwinaria canadensis, Blood-root, or Puccoon, has emetic and purgative properties. Order 10.—Fumariacea, the Fumitory Family., (Polypet. Hypog.) Sepals 2, caducous. Petals 4, cruciate; one or both of the two outer gibbous at the base, the two inner cohering at the apex. Stamens hypogy- nous, usually 6, diadelphous ; anther of middle stamen of each parcel bilocular, outer ones unilocular. Ovary free, 1-celled ; style filiform ; stigma with 2 or more points ; ovules amphitropal, Fruit either an achzenium, or a 1-celled 2-seeded, or 2-valved many-seeded pod. Seeds crested; albumen fleshy; embryo minute, eccentric.— Herbaceous plants, with a watery juice, and alternate multifid leaves, Although at first sight very unlike the Poppy family, the Fumitories resemble this order in their deciduous sepals, in their seeds, and, in many cases, in their fruit. The two outer unilocular stamens of each parcel may be considered as forming one perfect stamen, thus making the whole number four. They are found chiefly in northern temperate latitudes. Two are found at the Cape of Good Hope. They are usually scentless, and are said to be bitter and diaphoretic in their properties. The tuber of Corydalis bulbosa has been used as a substi- tute for Birthworts in expelling intestinal worms, and as an emmena- gogue. Authors notice 18 genera, including 134 species. Examples— Fumaria, Corydalis, Dicentra (Dielytra), Hypecoum. Order 11.— Crucirer#, the Cruciferous or Cresswort Family, Fig, 670. Fig. 673. Fig. 671. two lateral ones gibbous at the base. Petals 4 rarely wanting (as in Pringlea), hypogynous, alternating with the sepals, deciduous, cruciate Figs. 670-677. Organs of fructification of Erysimum lanceolatum, one of the Crucifere. Fig. 670. Diagram of the flower, showing the arrangement of four sepals, four petals alternating with them, six tetradynamous stamens, and a siliqua with replum. Fig. 671. Vertical section of the flower. c, Calyx. , Petals. e, Stamens. o, Ovary laid open. s, Stigma. Fig. 672. Flower deprived of its envelopes. ec, ¢, Cicatrices left by the fall of the sepals, g, Glands which are situated at the base of the stamens, e’, Two short stamens opposite lateral sepals. e”, Four long stamens opposite anterior and posterior sepals. 7, Pistil Fig. 673. Horizontal section of the ovary. g, Ovules. c, Spurious dissepiment or replum, which divides the ovary into two cavities. This replum is formed by the placentas. CRUCIFERZ. 435 (fig. 315, p. 204). Stamens 6, tetradynamous (figs. 372, p. 226; 672) ; two shorter solitary (fig. 672 ¢’) opposite the lateral sepals, occasion- ally toothed ; four longer (fig. 672 ¢’), opposite the anterior and pos- terior sepals, generally free, sometimes partially united and furnished with a tooth on the inside ; anthers bilocular, introrse (fig. 671); (in Megacarpea polyandra the stamens are numerous). Torus with green glands between the petals and stamens and ovary (fig. 672.9). Ovary superior, with parietal placentas, which meet in the middle, forming a spurious dissepiment or replum (fig. 673 c); stigmas 2, opposite the placentas, or anterior and posterior (fig. 552 s, p. 306). Fruit a siliqua (figs. 674, 675), or a silicula, rarely 1-celled and indehiscent, usually spuriously 2-celled and dehiscing by two valves, which sepa- rate from the replum (figs. 5527, p. 306; 675), one- or many-seeded. Seeds campylotropous (figs. 455, p. 255; Fig. 676. 620, p. 342), pendulous, attached in a single row by a funiculus to each side of the pla- centas (fig. 676) ; perisperm none; embryo with the radicle folded upon the cotyledons which are next the placenta (figs. 620, p. 342 ; 677 r).—Herbaceous plants seldom under- shrubs, with alternate leaves, and yellow or white, rarely purple, flowers, without bracts. This order is well distinguished by having tetradynamous stamens. Most of the plants belonging to the order are European. The species, however, are found scattered all over the world. Authors enumerate 172 genera, Fig. 677. Fig. 675. Fig. 674. including 1700 species. Examples—Draba, Lepidium, Isatis, Brassica, Sinapis, Bunias, Senebiera, Schizopetalon, Pringlea, Megacarpza. The order has been subdivided into sections, according to the mode in which the radicle of the embryo is folded on the cotyledons, as well as according to the nature of the fruit. The sub-orders founded on the embryo are—1, Pleurorhizez (rAeved, side, and é/Za, root), 0 = cotyle- dons accumbent, radicle lateral, z.c. applied to their edge, as in Stock, (fig. 613, p. 340). 2. Notorhizeze (véros, back), 0 || cotyledons incum- bent, radicle dorsal, i.e. applied to their back, as in Shepherd’s purse, (fig. 614, p. 340). 3. Orthoplocese é20é¢, straight, and rAéxos, a plait or fold, 077 cotyledons conduplicate (folded), radicle dorsal, as in Mustard (figs. 609, p. 339; 677). 4. Spirolobez (o7e7gu, a coil, and robs, a phe 0 || || cotyledons folded spirally, radicle dorsal as in Bunias (fig. 611, p. 339).. 5. Diplecolobese (dis, twice, raexw, I fold ; Fig. 674. Siliqua or long pod. Fig. 675. Siliqua with one of its valves removed, in order to show the seeds attached to the replum, - Fig. 676. Vertical section of the seed. Jf, Funiculus or umbilical cord. ¢, Spermoderm or testa swollen at the chalaza,c. 7, Radicle. c, Cotyledons. Fig. 677. Horizontal section of the seed. ¢, Spermoderm or testa. r, Radicle, c, Incumbent cotyledons, 436 CRUCIFERA. or plait, and AoBEs, a lobe), 0 |||| || cotyledons twice folded, in a spiral, radicle dorsal, as in Subularia. The tribes Pleurorhizex and Noto- rhizez are sometimes included under the name Platylobew, meaning that the cotyledons are plane or flat (wAards, broad). The divisions founded on the seed-vessel are—1. Siliquose, a siliqua, linear or linear-lanceolate, valves opening longitudinally, as in Wallflower. 2. Siliculosze Latiseptee (Jatus, broad, and septwm, par- tition), a silicula, partition in its broadest diameter, oval or oblong, valves flat or convex, opening longitudinally, as in Thlaspi. 3. Sili- culos angustiseptze (angustus, narrow), a silicula, partition in its nar- row diameter, linear or lanceolate, valves opening longitudinally, folded and keeled as in Capsella. 4. Nucumentacese (nucumentum, a nut), silicula, valves indistinct or indehiscent, often 1-celled, from the absence of the replum or partition, as in Isatis. 5. Septulatz (septa, parti- tions), valves opening longitudinally, furnished with transverse parti- tions in.their interior, as in Anastatica. 6. Lomentaceze (omentum, an articulate legume), siliqua or silicula, dividing transversely into single-seeded cells, the true siliqua being often barren, and all the seeds placed in the beak, as in Sea-kale. In this order there is a want of symmetry as regards the number of stamens, compared with the floral envelopes. The two long stamens placed close together may, however, be looked upon as one divided by a process of deduplication, so that the actual number will thus be reduced to four. This view is confirmed by the shorter stamens having teeth on each side, while the longer ones are toothed on one side only. By pelorization, too, some Cruciferze become tetrandrous. While there is a splitting of the filaments, there is also the production of two additional anther-lobes. Others think that the androecium of Cruciferze is composed of two quaternary whorls, the lower one being composed of the two lateral short stamens only, the other two, which should be developed in front of the antero-posterior sepals, being abortive ; while the upper whorl is composed of the four long stamens which approach each other and form two pairs, In regard to the fruit, it has been stated that normally there are four carpidia or carpels, two of which are constantly abortive. In some species of Iberis there have been seen four sepals, four petals, four stamens, and four carpels. Thus the floral type of Cruciferze is quaternary: calyx having four sepals, corolla four petals, receptacle four staminiferous glands, androe- cium four stamens, gyncecium four phyllidia, fruit four carpidia. There are no truly poisonous plants in the ‘order. In general, it possesses antiscorbutic and stimulant qualities, with a certain degree of acridity. Many of the most common culinary vegetables belong to the order, such as Cabbages, Cauliflower, Turnip, Radish, Cress, Horse- radish, etc. They contain much sulphur and nitrogen, and on this account, when decaying, give off a disagreeable odour. Many garden CAPPARIDACES, 437 flowers, such as Wallflower, Stock, Rocket, and Honesty, are found in this order. Brassica oleracea is the original species whence all the varieties of Cabbage, Cauliflower, Brocoli, and Savoys, have been obtained by the art of the gardener. The part of the Cauliflower used as food is the deformed flower-stalks. Brassica Rapa is the common Turnip, while Brassica campestris is the source of the Swedish turnip. Brassica Napus, Rape or Coleseed, yields Colza and Carcel oils. Some consider Brassica campestris, Rapa, and Napus, as sub-species. Bras- sica chinensis yields Shanghae oil. Lepidiwm sativum is the common Cress, and Raphanus sativus the Radish. Crambe maritima is the Sea- kale. The seeds of Sinapis nigra (Brassica nigra of some) furnish table mustard. These contain a bland fixed oil, a peculiar bitter principle, myronic acid, and another principle analogous to albumen or emulsin, called myrosine. When water is added, the myronic acid and myro- sine, by their combination, form a pungent volatile oil, containing sulphur and nitrogen, which gives to mustard its peculiar properties ; a crystallisable substance called myronate of potassium, now called sinigrin, is found in Mustard. Sinapis alba furnishes white Mustard, which contains more fixed oil than black mustard. It does not, however, contain myronic acid, but an analogous principle called sinapin, or sinapisin, which, by combination with another principle, forms an acrid compound, but not a volatile oil. The mustard of Scripture, according to Royle, is not a species of Sinapis, but Salvadora persica, belonging to the natural order Chenopodiacew, This view is not con- firmed by Dr. Tristram, who says that the mustard plant of Scripture (sivaim) is Sinapis nigra, Black Mustard, while Salvadora is a tropical plant, growing on the north of the Dead Sea, and not found generally in Palestine. Many other Cruciferous plants yield volatile oils con- taining sulphur, and the seeds of many yield by expression a bland fixed oil, such as Rape-seed oil. Cochlearta officinalis, common Scurvy- grass, is used asa stimulant. Cochlearia Armoracia, or Armoracia rusti- cana, the Horse-Radish, has irritant and even vesicant qualities, Ana- statica hierochuntina, Rose of Jericho, is remarkable for the hygrometric property of the old withered annual stems, which are rolled up like a ball in dry weather, and drifted about by the winds in the deserts of Syria and Egypt. If rain falls, they resume their original position. They thus continue for many years to curl up and expand, according to the state of the atmosphere. The genus Schizopetalon is remark- able on account of its tetracotyledonous (having four cotyledons) embryo. satis tinctoria, Woad, when treated like Indigo, yields a blue dye. satis indigotica is the Tein-Ching, or Chinese Indigo. . Pringlea antiscorbutica, Kerguelen Island Cabbage, is found in that island, as well as in Tristan d’Acunha, Marion Island, and Heard Island. It has no petals, no glands, and the stigma is hairy. Order 12.—CappariDaces, the Caper Family. (Polypet. Hypog.) 438 RESEDACEA, Sepals 4-12, often more or less cohering (fig. 654, p. 371). Petals 4-8, sometimes 0, cruciate (fig. 654, p), usually unguiculate and un- equal, Stamens hypogynous, 4-6 (fig. 654 e), or 00, but in general some high multiple of four, placed on an elongated hemispherical and often glandular torus (fig. 654 ag’). Ovary usually stalked (fig. 654 0); styles filiform, sometimes 0; ovules curved. Fruit unilo- cular, siliqueeform and ‘dehiscent, or fleshy and indehiscent, rarely monospermous, usually with two polyspermous parietal placentas. Seeds generally reniform and exalbuminous ; embryo curved ; cotyle- dons foliaceous, flattish—Herbs, shrubs, sometimes trees, with alter- nate, stalked, undivided, or palmate leaves, which are either exstipu- late or have spines at their base. Capparids may be distinguished from Crucifers by their stamens being often indefinite, or, if definite, scarcely ever tetradynamous, while their ovary is usually stipitate, their fruit often succulent, and their seeds generally reniform. They are found chiefly in warm countries, and are abundant in Africa. There are 23 genera, and 300 species. The order is divided into two sub- orders :—1. Cleomez, with capsular fruit. 2. Cappareze, with baccate fruit. Examples—Cleome, Capparis. 5 The plants of this order have stimulant qualities. The flower- buds of Capparis spinosa furnish capers. The plant is a native of the south of Europe. It, or C. egyptiaca, is supposed to be the Hyssop (28) of Scripture ; but there is a difficulty in deciding the point. Some species of Cleome and Polanisia are very pungent, and are used as substitutes for mustard. The pungency of some is so great that they act as blisters. The root of Cleome dodecandra is used as an anthelmintic. Order 13.— Resepaces, the Mignonette Family. (Polypet. Hypog.) Calyx many-parted. Petals 4-6, unequal, entire, or lacer- ated, in the latter case consisting of a broad scale-like claw with a much-divided limb. Stamens 3-40, hypogynous, attached to a gland- ular torus ; filaments variously united ; anthers bilocular, innate, with longitudinal dehiscence. Ovary sessile, 3-lobed, 1-celled, multiovular, with 3-6 parietal placentas; stigmas 3. Fruit either a unilocular many-seeded capsule, opening at the apex so as to render the seeds seminude (fig. 575, p. 326), or 3-6 few-seeded follicles. Seeds reni- form, usually exalbuminous ; embryo curved ; radicle superior ; coty- ledons fleshy.—Herbaceous plants, rarely shrubs, with alternate, entire, or divided leaves, having gland-like stipules. They inhabit chiefly Europe and the adjoining parts of Asia. A few are found in the north of India and south of Africa. The uses of the order are unimportant. Reseda Luteola, Weld, yields a yellow dye. Reseda odorata is the fragrant Mignonette. The Mignonette is rendered suffruticose by preventing the development of its blossoms. This is the origin of the tree Mignonette, which is much cultivated in France. There are 6 known genera, and 30 species. Hxample—Reseda. CISTACEH—CANELLACEA, 439 Order 14.—Cistacr#, the Rock-Rose Family. (Polypet. Hypog.) Sepals usually 5, persistent, unequal, the three inner with contorted estivation. Petals 5, caducous, hypogynous, estivation corrugated, and twisted in an opposite direction to that of the sepals. Stamens usually 00, free, hypogynous ; anthers 2-celled, adnate. Ovary syn- carpous, l- or many-celled ; style single; stigma simple. Fruit cap- sular, 3-5-10-valved, either 1-celled or imperfectly 5-10-celled, with loculicidal dehiscence. Seeds usually indefinite; embryo inverted, either spiral or curved, in the midst of mealy albumen ; radicle remote from the hilum.—Shrubs or herbaceous plants with entire, opposite, or alternate, stipulate or. exstipulate leaves. They inhabit chiefly the southern regions of Europe, and the north of Africa. Some of the species are remarkable for the irritability of their stamens (p. 386). Many of them yield a resinous balsamic juice, which imparts viscidity to the branches. The resinous matter called ladanum or labdanum is yielded by Cistus creticus and other species. There are 4 known genera, and 100 species, according to authors. Examples—Cistus, Helianthemum, Hudsonia, Lechea. Order 15.—CANELLACEa, the Canella Family. Flowers herma- phrodite, with imbricated bracteoles (sepals of some authors). Sepals (petals of some) 4-5. Petals (petaloid scales of some) 4-5, sometimes 0. Stamens 20, hypogynous, with connate filaments. Disk 0. Ovary free, unilocular ; placentas 2-5 parietal ; style short; stigmas 2-5; ovules ascending or horizontal. Fruit baccate, 2- or many-seeded. Seeds with a shining testa ; albumen fleshy and oily ; embryo straight or curved.— Glabrous aromatic trees, with alternate exstipulate leaves and cymose flowers. Natives of tropical America. There are 3 known genera and 5 species. Hxamples—Canella, Cinnamodendron. Canelle alba, a tree 30-50 feet in height, a native of the West Indies, yields the canella bark, called also White Cinnamon, which is imported from the Bahamas. It yields several kinds of oils, and is an aromatic stimulant. Cinnamodendron corticosum yields an aromatic bark in the West Indies. Order 16.—Brxacra@, the Arnatto or Annatto Family. (Polypet. Hypog.) Sepals 4-7, slightly cohering. Petals equal to and alternat- ing with the sepals, or wanting. Stamens hypogynous, equal in number to the petals, or some multiple of them. Ovary roundish, sessile or slightly stalked; style either none or filiform; stigmas several, more or less distinct ; ovules attached to parietal placentas, which sometimes branch all over the inner surface of the valves. Fruit 1-celled, containing a thin pulp, either fleshy and indehiscent, or capsular, with 4 or 5 valves. Seeds numerous, enveloped in a covering formed by the withered pulp; albumen fleshy, somewhat oily; embryo axile, straight; radicle turned towards the hilum ; cotyledons flat, foliaceous.—Shrubs or small trees, with alternate, 440 BIXACEAI—VIOLACE:. simple, usually exstipulate leaves, which are ofted dotted. The plants are chiefly natives of the warmest parts of the East and West Indies, and of Africa. The order is divided into 4 tribes:—1. Bixex. 2. Oncobes. 3. Flacourtier. 4. Pangiez. Many of the plants yield edible fruits. The pulp is often sweet and wholesome. Some are astringent, others purgative. The red- dish pulp surrounding the seeds of Bixa orellana supplies the sub- stance called arnatto, which is used for yielding a red colour, and for staining cheese. The seeds are cordial, astringent and febrifugal. The seeds of Trichadenia zeylanica, a large tree of Ceylon, called Tettigaha or Tettigass, yield an oil used for burning. The oil expressed from the seeds of Gynocardia odorata (called chalmugra seeds) is used in India for the cure of leprosy, and for various cutaneous diseases. The tree is poisonous, but the seeds yield by expression a bland fixed oil having a peculiar smell and taste. The surface of the leprous ulcers is dressed with the oil, while a six-grain pill of the seed is given three times a day. The seeds are prescribed in cases of scrofula, skin diseases, and rheumatism. The fruit of Hydnocarpus venenatus and H. Toon is used to poison fish. There are 30 genera, and 160 species, according to authors, Hxamples—Bixa, Oncoba, Flacourtia, Aberia, Gynocardia, Pangium. Order 17.—VioLacz#, the Violet Family. (Polypet. Hypog.) Sepals 5, persistent usually elongated at the base, estivation imbri- cated. Petals 5, hypogynous, equal or unequal, generally withering, zstivation obliquely convolute. Stamens 5, alternate with the petals, sometimes opposite to them, inserted on a hypogynous torus ; anthers dithecal, introrse, often cohering, with a prolonged connective some- times spurred (fig. 375, p. 225); filaments dilated, two of them in the irregular flowers having an appendage at their base. Ovary uni- locular, with many anatropal ovules, rarely one; style single, usually declinate, with an oblique hooded stigma (fig. 424, 1. s, p. 242). Fruit a 3-valved capsule, dehiscence loculicidal, placentas on the middle of the valves (fig. 424, p. 242). Seeds 00 or definite ; em- bryo straight, erect, in the axis of a fleshy perisperm.—Herbs or shrubs, with alternate, rarely opposite, leaves, having persistent stipules, and an involute vernation. They are natives of Europe, Asia, and America. The herbaceous species inhabit chiefly the tem- perate parts of the northern hemisphere, while the shrubby species are found in South America and India. They have been divided into three tribes :—1. Violece, with irregular flowers. 2. Papayrolez, with irregular corolla, and slightly coherent claws. 3, Alsodex, with regular flowers. To these some authors add a fourth tribe, Sauvagesiez, having anthers without appendages, and septicidal dehiscence. Their distinctive peculiarity may be regarded as resting in their definite stamens, whose anthers turn inwards, and extend their connective into DROSERACEAi—POLYGALACEA, 441 a crest. There are 21 known genera, and about 300 species. Examples—Viola, Ionidium, Papayrola, Alsodeia. They are distinguished by the emetic properties of their roots, which contain an active principle called violin, similar in its qualities to emetin. Some species of lonidium are used in South America as substitutes for Ipecacuan. The roots of Viola odorata, the Sweet or March Violet, the ‘ov of the Greeks, have been used medicinally as an emetic ; the petals are laxative, and are used in the form of infu- sion mixed with sugar; and a violet or purple colouring matter is procured from them, which is employed as a test for acids and alkalies, being changed into red by the former, and into green by the latter. Viola tricolor, Heart’s ease, and other species, have been used as demulcent expectorants. V. tricolor is the origin of all the culti- vated varieties of pansy. Order 18.—Droseraces, the Sundew Family. (Polypet. Hypog.) Sepals 5, persistent, equal; estivation imbricated. Petals 5, hypo- gynous. Stamens free, withering, alternate with the petals, or 10 or more ; anthers bilocular, with longitudinal dehiscence. Ovary single ; styles usually 3-5; sometimes 1 or wanting. Fruit, a unilocular or spuriously trilocular capsule, 3-5-valved, with loculicidal dehiscence, occasionally indehiscent. Seeds numerous, either albuminous or ex- albuminous; embryo minute and erect. — Herbaceous: plants with alternate leaves, usually inhabiting marshy places. They are found in various parts of the world, in Europe, Australia, North and South America, South Africa, China, East Indies, etc. The order is con- sidered by some as allied to Saxifragaceze. There are 6 known genera, and about 110 species. Hxamples— Drosera, Drosophyllum, Aldro- vanda, Dionzea, The Droseras have a more or less acid taste, combined with slight acridity. Some of them are said to be poisonous to cattle. Their leaves are furnished with glandular capitate hairs (fig. 88, p. 32; fig. 661, p. 383), which are covered with drops of fluid in sunshine ; hence the name Sundew or fos solis. An Italian liqueur, called Rossoli, derives its name from a Drosera used in its manufacture. Some of the Droseras have dyeing properties. The hairs of Drosera have a spiral coil in their interior. They fold upon insects. (For a full account of the phenomena connected with the irritability of these plants, see pages 380-383). Dionea muscipula, Venus’s fly-trap, is a North American plant, having the lamine of the leaves in two halves, each furnished with three irritable hairs, which, on being touched, cause the folding of the divisions in an upward direction (fig. 660, p. 380). It is insectivorous. Aldrovandra vesiculosa, an aquatic found in the south of Europe, is distinguished by its whorled cellular leaves, or floating bladders. Order 19.— Potyeataces, the Milkwort Family. (Polypet. 442 TREMANDRACEA—TAMARICACEZ, Hypog.) Sepals 5, very irregular, distinct ; 3 exterior, of which 1 is superior, and 2 inferior; 2 interior, usually petaloid, lateral ; cstiva- tion imbricated. Petals hypogynous, unequal, usually 3, of which 1 is anterior, and larger than the rest, and 2 are alternate with the upper and lateral sepals; sometimes there are 5 petals, 2 of them very minute ; the anterior petal, called the keel, is often crested. Stamens hypogynous, 8, monadelphous or diadelphous ; anthers clavate, usually l-celled, and having porous dehiscence. Ovary mostly bilocular ; ovules solitary, rarely 2; style simple, curved ; stigma simple. Fruit dehiscing in a loculicidal manner, or indehiscent. Seeds pendulous, anatropal, strophiolate at the hilum ; albumen fleshy, embryo straight. —Shrubs or herbs with alternate or opposite exstipulate leaves. They are found in all quarters of the globe. Authors mention 15 genera, including 400 species. Hxamples— Polygala, Securidaca, Krameria. In the appearance of their flowers the plants of this order have a resemblance to Papilionacee. They are distinguished, however, by the odd petal being inferior, and the sepal superior. They are gene- rally bitter, and their roots yield a milky juice. Polygala Senega, Senega or Seneka root, called also Snake-root, is a North American species, the root of which is used medicinally, in large doses, as emetic and cathartic; and in small doses as a stimulant, sudorific, expec- torant, and sialagogue. It contains an acrid principle called senegin, and polygalic acid. The name of Snake-root was given from its sup- posed use as an antidote to the bite of the rattlesnake, Krameria triandra, a Peruvian plant, furnishes Rhatany-root, which is employed as a powerful and pure astringent in cases of hemorrhage and chropic mucous discharges. Its infusion is of a blood-red colour, and has been employed to adulterate port wine. A Chilian plant, Krameria cistoidea, also yields a kind of rhatany. - Order 20. — TREMANDRACES, the Porewort Family. (Polypet. Hypog.) Sepals 4-5, slightly coherent, deciduous, with a valvate estivation. Petals 4-5, deciduous, with an involute estivation. Stamens hypogynous, distinct, 8-10, 2 before each petal; anther di- or tetra-thecal, with porous dehiscence (fig. 356, p. 222). Ovary bilocu- lar, with 1-3 pendulous ovules in each cell ; style, 1; stigmas, 1-2. Fruit a 2-celled, 2-valved capsule, with loculicidal dehiscence. Seeds ana- tropal, pendulous, with a caruncula at the apex ; embryo cylindrical, straight, in the axis of fleshy albumen. — Heath-like shrubs, with hairs usually glandular, alternate or verticillate exstipulate leaves, and solitary axillary 1-flowered pedicels. They are natives of extra- tropical Australia. Nothing is known regarding their properties. Authors mention 3 genera, including 24 species. Hxamples—Tetra- theca, Tremandra, . Order 21.—Tamaricacrea, the Tamarisk Family. (Polypet. FRANKENIACEE—ELATINACEA, 443 Hypog.). Calyx 4-5 partite, persistent, with imbricated zstivation. Petals 4-5, hypogynous, or perhaps inserted at the base of the calyx, marcescent, with imbricated estivation. Stamens hypogynous, free or monadelphous (fig. 343, p. 217), equal to the petals in number, or twice as many; anthers dithecal, introrse, with longitudinal dehis- cence. Ovary unilocular; styles, 3. Fruit a 3-valved, 1-celled cap- sule, with loculicidal dehiscence. Seeds numerous, anatropal, erect or ascending, comose; albumen 0; embryo straight, with the radicle next the hilum.—Shrubs or herbs, with alternate scale-like leaves, and racemose or spiked flowers. They abound in the Mediterranean region, and are confined chiefly to the eastern half of the northern hemisphere. Many are found in the vicinity of the sea. They have a bitter astrin- gent bark, and some of them yield a quantity of sulphate of soda when burned. The saccharine substance called Tamarisk or Mount Sinai Manna, is yielded by Tamarix gallica, var, mannifera, as the result of puncture by an insect called Coccus manniparus, The plant grows in the valleys of the peninsula of Sinai. Tamarix orientalis of North Western India furnishes galls, which are used in place of oak-galls. Authors mention 5 genera, comprising 40 species. Ezamples—Tamarix, Myricaria, Reaumuria. Order 22.—FRANKENIACE#, the Frankenia Family. (Polypet. Hypog.) Sepals 4-5, cohering into a tube, persistent. Petals 4-5, alternate with the sepals, hypogynous. Stamens hypogynous, equal in number to the petals, and alternate with them, sometimes more numerous ; anthers bilocular, with longitudinal dehiscence. Ovary unilocular, with parietal placentas ; style filiform, often trifid. Fruit a l-celled, usually 3-valved capsule, with septicidal dehiscence. This latter distinguishes them from the Violet-worts to which they are allied. Seeds very minute, numerous, anatropal ; embryo straight, in the axis of fleshy albumen.—Herbs or undershrubs, with opposite exstipulate leaves. They are found chiefly on extratropical maritime shores. They are said to have mucilaginous and slightly aromatic properties. Genera, 3; species, 30. Zxample—Frankenia. Order 23.—Exatinace#, the Water-pepper Family. (Polypet. Hypog.) Sepals 3-5, free, or slightly coherent at the base. Petals alternate with the sepals, hypogynous. Stamens hypogynous, equal to, or twice as many as, the petals. Ovary tri-quinquelocular ; styles 3-5 ; stigmas, capitate. Fruit capsular, 3-5 celled, 3-5 valved, locu- licidal ; placenta central. Seeds 00, exalbuminous, anatropal ; embryo cylindrical and slightly curved.—Annual marsh plants, with hollow creeping stems, and opposite stipulate leaves. They are found “in all parts of the globe. Some of them have acridity, and hence the name Water-pepper. Genera 2, and species 20. The Elatines are natives of Europe and Asia, Bergias of the Cape of Good Hope. Examples—Elatine, Bergia. 444, CARYOPHYLLACEA. Order 24,—CaryvoruyLLaces, the Chickweed Family. (Polypet. Hypog.) Sepals 4-5 (fig. 678), free (fig. 293, p. 136), or united in a tube (figs. 297 c, p. 197; 653 ¢, p. 371), persistent. Petals 4-5 (fig. 678), hypogynous, unguiculate (fig. 305, p. 201), often bifid or bipar- tite (fig. 307, p. 201), occasionally 0. Stamens (fig. 679 ¢) usually double the number of the petals, or, if equal, usually alternate with them ; filaments subulate, sometimes united ; anthers innate, bilocular, dehiscence longitudinal. Ovary single, often stalked or supported on a gynophore (fig. 653 g, p. 371), composed of 2 to 5 carpels, which are usually united by their edges, but sometimes the edges are turned in- Fig. 678. Fig. 681. Fig. 679. Fig. 682. wards, so as to form partial dissepiments ; stigmas 2-5 (figs. 425, 426 s, p. 242), with papille on their inner surface (fig. 679 s). Capsule unilocular (figs. 425, p. 242; 681, 2), or imperfectly bi-quinquelocular Fig. 678-682. Illustrations of the natural order Caryophyllacee. Fig. 678. Diagram of the flower of Alsine media, common Chickweed, belonging to the natural order Caryo- phyllacee, tribe Alsinee. The flower consists of five imbricate sepals, five alternate petals, five stamens, a unilocular ovary, with a free central placenta, and numerous ovules, Fig. 679. Section of the flower of Dianthus Caryophyllus, Carnation. c, Calyx; p, petals, cohering with the stamens at the base; e, stamens; g, gynophore or thecaphore, i.e. the stalk supporting the ovary; 0, ovary with central placenta and ovules ; s, two stigmas, which are papillose all along their inner surface. Fig. 680. Horizontal section of the ovary in a very young state, showing the partitions cc, which divide the ovary into two cavities, These divisions ultimately disappear, leaving the placenta, p, bearing the ovules free in the centre. Fig. 681. Capsule of Lychnis Githago at the period of dehiscehce, when the pericarp separates into five valves at the summit, 1, The capsule entire. 2, Capsule cut vertically, to show the seeds, g, grouped in a mass, on a free central placenta, p. Fig. 682. Seeds. 1, Entire seed. 2, Seed cut vertically. ¢,Spermoderm. e, Peri- pherical embryo, surrounding the mealy perisperm, p. PORTULACACEA, 445 (fig. 680), 2-5 valved, opening ther by valves, or more commonly by twice as many teeth as stigmas (figs. 540, p. 303; 681), placenta in the axis of the fruit (figs. 425, p. 242; 681, 2, p). Seeds usually 00, amphitropal with mealy affumen, and a peripherical embryo (fig. 682).—Herbs, sometimes suffruticose plants, with opposite, entire, exstipulate, sometimes‘ connate leaves, and usually cymose inflor- escence (figs. 270, 271, p. 183)», They inhabit chiefly temperate and cold regions, According to the calculation of Humboldt, Cloveworts constitute 7: of the flowering plants of France, zy of Germany, zy of . Lapland, and vz of North America. Those found within the tropics are usually met with on high elevations and mountainous tracts, many of them exclusively vegetate in regions of the lowest temperature. The order has been divided into two tribes :—1. Alsinex, sepals dis- tinct (fig. 293, p. 136). 2. Sileneze, sepals cohering in a tube (fig. 297, p. 197). Authors mention 35 genera, and 1000 species. Ez- amples—Alsine, Cerastium, Dianthus, Silene, Polycarpon. The plants of this order are usually insipid, but some are said to be ~ poisonous. The poisonous quality is attributed to Saponine, which exists in many of the species of Saponaria, Silene, Lychnis, and Dianthus, To saponine, also, is due the saponaceous or soap-like properties of the plants. Honkeneja peploides has been used as a pickle. In Iceland it serves as an article of food. The greater part of the plants of the order are weeds, but some are showy garden flowers. To the latter may be referred all the varieties of Dianthus Caryophyllus, Clove-pink or Carnation, Picotees, Bizarres, and Flakes, numerous species of Pink, Campion, etc. The varieties of Carnation depend on the mode in which the coloured stripes or dots are arranged on the petals, and the entire or serrated appearance of their edges. The formation of the placenta in the Caryophyllacee has given rise to discussion, some looking upon it as a marginal, others as an axile formation (p. 243). Order 25.—PortuLacaces, the Purslane Family. (Polypet. Hypo-Perigyn.) Sepals 2, cohering at the base. Petals usually 5, rarely wanting, distinct or cohering at the base, sometimes hypogy- nous. Stamens perigynous or hypogynous, variable in number, all fertile, sometimes opposite the petals; filaments distinct; anthers versatile, bilocular, with longitudinal dehiscence. Ovary free or par- tially adherent, I-celled, formed by 3 united carpels; style single or 0; stigmas several. Fruit capsular, 1-celled, opening by circumscissile dehiscence, or by 3 valves, occasionally monospermous and indehiscent. Seeds numerous or definite, or solitary, attached to a central placenta ; albumen farinaceous ; embryo peripherical ; radicle long.—Succulent shrubs or herbs, with alternate, seldom opposite, entire, exstipulate leaves, often having hairs in their axils, They are found in various parts of the world, chiefly, however, in South America and at the, Cape of Good Hope. They always inhabit dry parched places. They 446 MALVACE. have a great affinity to Caryophyllacex, from which they are chiefly distinguished by their bisepalous calyx, their stamens being often perigynous, and their transversely dehiscent capsule. The plants belonging to the order have few properties of importance. They are insipid and destitute of odour. Portulaca oleracea, common Purslane, is used as a potherb on account of its cooling and antiscorbutic quali- ties; the ancients thought the seeds, steeped in wine, to be an emmenagogue. The tuberous roots of Claytonta tuberosa, a Siberian plant, are eaten ; and those of Melloca (Ullucus) tuberosa, a native of Peru, have been recommended as a substitute for the potato. In Portulaca oleracea and grandiflora the stamens, if brushed lightly in any direction, will immediately, with a strong impulse, bend over to the point from which they were brushed. There are 15 known genera, and 125 species. Hxamples—Portulaca, Talinum, Calandrinia, Claytonia, Montia, Order 26.—Matzvacez, the Mallow Family. (Polypet. Hypog.) Sepals 5 (fig. 683), rarely 3 or 4, more or less cohering at the base (fig. 298 ¢, p. 197), with a valvate zstivation (fig. 287, p. 194), often bearing an external calyx (epicalyx) or involucre (fig. 298 b, p. 197). Petals equal in number to the sepals; estivation twisted (fig. 286, p. 194). Stamens 00 (fig. 685 a), hypogynous, all perfect ; filaments “ Fig. 683.5 Fig, 684. monadelphous (fig. 685 ¢), or polyadelphous (fig. 651, p. 370) ; anthers monothecal (fig. 360, p. 222), reniform (fig. 686), with transverse dehiscence. Ovary formed by the uuion of several carpels round a common axis (figs. 417, p. 239; 548, p. 305; 687), either dis- tinct or cohering ; styles as many as the carpels (fig. 685 s), united or free. Fruit capsular or baccate; carpels one- or many-seeded, sometimes closely united, at other times separate or separable (figs. Figs. 683-691. Organs of fructification of Malva sylvestris, to illustrate the natural order Malvacez. Fig 683, Flower viewed from above, with its five petals, monadelphous stamens, peduncle or flower-stalk, and two stipules, s. Fig. 684. Diagram of the flower, showing the different whorls or verticils ; five valvate or induplicate sepals, five twisted petals, indefinite monadelphous stamens, and united carpels. MALVACEA. 447 687, 413, p. 238); dehiscence loculicidal (fig. 543, p. 304), or septi- cidal. Seeds amphitropal or semi-anatropal ; albumen 0, or in very small quantity; embryo curved (fig. 690); cotyledons twisted or doubled (fig. 691) Herbaceous plants, trees or shrubs, with alternate stipulate leaves (fig. 683 s), more or less divided, and often with rai Fp cy \\ Fig. 686, Fig. 685. " Fig. 691. Fig. 687. stellate hairs (fig. 86, p. 31). They are dispersed over all parts of the world, with the exception of the Arctic regions. They abound in tropical countries and in the warm parts of the temperate zone. Authors enumerate 40 genera, including about 700 species. The order has been divided into three tribes :—1. Malves, calyx with an involucel, carpels 5 or many, whorled, separating from the axis when ripe. 2. Hibiscese, calyx with an involucel; carpels 3-5-10, united into a loculicidal capsule. 3. Sideze, calyx naked ; fruit syncarpous. Examples—Lavatera, Malva, Hibiscus, Sida. The plants of the order are all wholesome, and yield mucilage in large quantity. Some furnish materials for cordage, others supply cotton. Malva sylvestris, Common Mallow, and Althea officinalis, Marsh Mallow, are employed medicinally, as demulcents and emol- lients. The latter is the Guimauve of the French. The flowers of Althea rosea, the Hollyhock, are officinal in Greece for similar pur- poses ; the plant also yields fibres and a blue dye. The petals of Malva Alcea and Hibiscus Rosa-sinensis possess astringent properties ; the Chinese make use of them to blacken their eyebrows and the leather of their shoes. The flowers of Abutilon esculentum, and the Fig. 685. Vertical section of the flower. 4, Caliculus, epicalyx, or involucre; ¢, calyx ; p, petals; t, tube of monadelphous stamens, forming an arch above the ovary, ov, and united at the base to the petals; a, anthers at the summit of the filaments, free ; s, styles free at the summit, united below. Fig. 686. A reniform monothecal anther, dehiscing transversely, separated with the upper part of the filament. Fig. 687. Fruit, surrounded by the persistent calyx, c, consisting of whorled carpels united together by the axis, a. Fig. 688. A separate carpel viewed laterally. Fig. 689. Exalbuminous amphitropal seed. Fig. 690, Curved embryo. Fig. 691. Section of the embryo, to show the doubled coty- ledons. 448 STERCULIACEA. fruit of Abelmoschus esculentus (Hibiscus esculentus), called Ochro and Gombo, are used as articles of food. Hibiscus cannabinus is the source whence sunnee-hemp is procured in India. Hibiscus mutabilis receives its name from the changing colour of its flowers, varying from a pale rose to a rich pink colour. Other species of Hibiscus as well as Pari- tiwm tiliacewm yield useful fibres. The bark of Paritiwm elatum fur- nishes Cuba Bast. Cotton is composed of the hairs surrounding the seeds of various species of Gossypiwm. These hairs, when dry, exhibit under the microscope a peculiar twisted appearance. Gossypium barbadense seems to be the species which yields the best cotton ; the Sea-Island, New Orleans, and Georgian cotton being produced by varieties of it. Gossypiwm peruvianum or acuminatum furnishes the South American cotton ; Gossypiwm herbacewm, the common cotton of India. G. arboreum is the Indian-tree cotton. The Chinese Nankin cotton is furnished by a variety of G. herbacewm. The quality of cotton-wool depends on the length, strength, and firmness of the tissue, or, as it is called, the staple. These essential attributes are modified by the cleanliness and the colour. Long-stapled cottons are generally used for the twist or warp, and short-stapled for the weft. The value of cotton varies not only according to the species, but also according to the nature of the climate in which it grows. The total import of raw Cotton into Britain in 1874 was upwards of 124 millions of cwts. The seeds of the cotton-plants yield oil which has been used for lamps; when bruised they are employed for oil-cake. Cotton is used in the preparation of gun-cotton and of collodion. Order 27,—Srercuiiaces, the Sterculia and Silk-cotton Family. (Polypet. Hypog.) Calyx of 5, more or less united, sepals, often sur- rounded by an involucre ; estivation usually valvate. Petals 5 or none, hypogynous, estivation twisted. Stamens usually o ; their filaments variously united ; anthers 2-celled, extrorse. FPistil of 5 (rarely 3) carpels, either distinct or cohering ; styles equal in number to the carpels, free or cohering ; ovules orthotropal (fig. 619, p. 342) or anatropal. Fruit capsular, usually with 5 cells, or follicular or succulent. Seeds often with a woolly covering; with a fleshy or oily perisperm (rarely 0), and either a straight or a curved embryo ; cotyledons leafy or thick, plaited or rolled round the plumule.—Trees or shrubs, with alternate leaves, which are either simple or compound, deciduous stipules, and often a stellate pubescence. They are distin- guished from Malvacese by their dithecal extrorse anthers. They inhabit warm climates. The order has been divided into the follow- ing tribes:—1. Bombacez, with hermaphrodite flowers and palmate or digitate leaves; found most abundantly in America. 2. Helic- tereze, with hermaphrodite flowers and simple leaves; apparently unknown in Africa. 3, Sterculiese, with unisexual flowers, and either simple or palmate leaves; chiefly in India and Africa. Authors men- BYTTNERIACEA. 449 tion 80 genera, including 130 species, Hxamples—Bombax, Helic- teres, Sterculia. The plants are mucilaginous and demulcent ; many are used for food, others supply a material like cotton. The silky hairs surround- ing the seeds of Bombax Ceiba, the Silk-cotton tree, are used for stuffing cushions and chairs, and for various other domestic purposes. They cannot be manufactured, in consequence of want of adhesion between the hairs. The trunk of the tree is made into canoes, Adan- sonia digitata, the Baobab tree of Senegal, or monkey-bread, is one of the largest known trees. Its trunk sometimes attains a diameter of thirty feet, while its height is by no means in proportion. The pulp of its fruit (amphisarca) is used as an article of food. It is emollient and mucilaginous in all its parts, The dried leaves when powdered constitute Jalo, a favourite article with the Africans, which they mix with their food for the purpose of diminishing the excessive perspira- tion to which in those climates they are subject. It is found by Europeans to be most serviceable in cases of diarrhoea, fevers, and other maladies. Adansonia Gregorit is the Gouty-stem tree of Australia. Durio zibethinus furnishes the fruit called Durian in the Indian Archi- pelago. The fruit is much prized, although it has a fetid odour, which has given rise to the name Civet Durian. The moment the fruit is ripe, it falls of itself, and the way to eat it in perfection is to get it as it falls. Brachychiton populneum is the Poplar Bottle-tree of Australia, Cheirostemon platanoides is called the Hand-plant of Mexico, on account of its five peculiarly curved anthers, which resemble a claw. Helicteres (from heliw, a snail) is so named on account of its twisted fruit. The Kola, mentioned by African travellers as being used to sweeten water, is the seed of Sterculia tomentosa or acuminata. Order 28.—ByTTNERIACE#, the Byttneria and Chocolate Family. (Polypet, Hypog.) Calyx 4-5 lobed, valvate in estivation (fig. 285 c, p. 194). Petals 4-5 or 0, often elongated at the apex, with a twisted or induplicate sestivation (fig. 285 p, p. 194). Stamens hypogynous, either equal in number to the petals, or some multiple of them, more. or less monadelphous, some of them sterile ; anthers bilocular, introrse. Ovary free, composed usually of 4-10 carpels arranged round a central column ; styles terminal, as many as the carpels, free or united ; ovules 2 in each loculament. Fruit capsular, either with loculicidal dehiscence, or the carpels separating from each other. Seeds anatropal, often winged ; embryo straight or curved, lying usually in fleshy albu- men ; cotyledons either plaited or rolled up spirally.—Trees, shrubs, , or undershrubs, with alternate leaves, having either deciduous stipules or 0, and stellate or forked hairs. They abound in tropical climates. Authors enumerate 30 genera, embracing about 400 species. Bytt- neriads are often united with Sterculiads, from which they are distin- guished by their slightly monadelphous stamens, and anthers tured 26 450 TILIACER. | inwards, Their two-celled anthers and non-columnar stamens distin- guish them from Mallow-worts. The order has been divided into six tribes, founded on the following genera: Examples —Lasiopetalum, Byttneria or Buttneria, Hermannia, Dombeya, Eriolzena, and Philip- podendron. The plants abound in mucilage, and many yield cordage. The seeds of Theobroma Cacao are called Cacao beans, and are the chief ingredient in chocolate, which contains also sugar, arnatto, vanilla, and cinnamon. The seeds by pressure yield a fatty oil, called Butter of Cacao, which has but little tendency to rancidity. They contain a crystalline principle analogous to caffeine called Theobromine. Other species of Theobroma also furnish Cacao-seeds, The Cocoa of the shops consists generally of the roasted beans, and sometimes of the roasted integuments of the beans, ground to powder. Order 29.—Ti1acez, the Lime-tree Family. (Polypet. Hypog.) Sepals 4-5, often with a valvate estivation. Petals 4-5, entire, rarely wanting. Stamens hypogynous, free, or united by the enlarged border of the stalk of the pistil (fig. 348, 1, 2, p. 219), usually oo ; anthers 2-celled, dehiscing longitudinally or by pores, occasionally some abortive (fig. 348, 2, p. 219). Disk often large and glandular. Ovary soli- tary, formed by the union of 2-10 carpels ; style 1; stigmas as many as the carpels. Fruit dry or pulpy, either multilocular with numerous seeds, or by abortion unilocular and 1-seeded. Seeds anatropal ; em- bryo erect in the axis of fleshy albumen, with flat, leafy cotyledons (fig. 606, p. 339).—Trees or shrubs, rarely herbaceous plants, with alternate stipulate leaves (fig. 211, p. 102). The principal part of the order is found within the tropics, forming weed-like plants, or shrubs, or trees, with handsome, usually white or pink flowers. A small number are peculiar to the northern parts of either hemisphere, where they form timber trees. The order has been divided into two sections : —l. Tiliez, with entire petals or 0, and anthers dehiscing longitu- dinally. 2. Eleeocarpez, with lacerated petals, and anthers opening at the apex. Authors enumerate 40 genera, including 330 species. Examples—Tilia, Corchorus, Grewia, Aristotelia, Eleeocarpus. The plants possess mucilaginous properties, and many of them furnish excellent materials for cordage. The fruit of some is edible. From the gummy matter they contain some have been employed as demulcents. The inner bark, the bast or bass, of the Linden or Lime-tree (Tilia Europea) is tough and fibrous, and from it are manu- factured Russian mats. The lime-trees of Europe are Tilia Europea, grandifolia, and parvifolia, The bark of Luhea grandiflora is used in Brazil for tanning leather. An infusion of the flowers is used on the continent as an antispasmodic and expectorant. Corchorus capsularis in India furnishes the Jute used for coarse carpets and gunny bags. The leaves of Corchorus olitorius, Jew’s-mallow, are used as a culinary DIPTEROCARPACEZ—-CHLZNACEA. 451 vegetable. C. pyriformis supplies fibres in Japan. The bark of Elxo- carpus is used as a tonic. The fruits of Grewia microcos and asiatica are agreeable, and are used for sherbet in N.W. India. Other species of Grewia yield cordage, and the fibres of G. oppositifolia are used for making paper. Order 30.—DrprerocaRPaces, the Sumatra-Camphor Family. (Polpet. Hypog.) Calyx tubular, 5-lobed, unequal, naked, persistent, and afterwards enlarged, with an imbricated estivation. Petals hypo- gynous, sessile, often combined at the base, with a twisted estivation. Stamens indefinite, hypogynous ; filaments dilated at the base, either distinct or irregularly cohering ; anthers innate, bilocular, subulate, opening by terminal fissures. Torus not enlarged in a disk-like man- ner. Ovary superior, 3-celled ; ovules in pairs, pendulous ; style and stigma simple. Fruit coriaceous, unilocular by abortion, 3-valved or indehiscent, surrounded by the calyx, which is prolonged in the form of long wing-like lobes. Seed solitary, exalbuminous; cotyledons often twisted and crumpled ; radicle superior.—Trees with alternate leaves, having an involute vernation, and deciduous convolute stipules. They are found in India, and especially in the eastern islands of the Indian Archipelago, where, according to Blume, they form the largest trees of the forest. There are about 10 known genera, including 100 species. Hxamples—Dipterocarpus, Vateria, Dryobalanops. The trees belonging to this order are handsome and ornamental, and they abound in resinous juice. A kind of Camphor is procured in Sumatra from Dryobalanops Camphora or aromatica, It is secreted in crystalline massés in cavities of the wood. It is less volatile than the common camphor of commerce. It supplies this cam- phor only after attaining a considerable age. In its young state it yields on incision a pale yellow liquid, called the liquid camphor of Borneo and Sumatra, which consists of resin and a volatile oil having a camphoraceous odour. Vateria Indica yields an oleo-resinous substance called white Dammar or Piney resin (called also Indian copal or gum animi), used in India as a varnish. From this resin a concrete oil is obtained, called Piney-tallow, or vegetable butter of Canara. The fruit of this tree yields to boiling water the celebrated butter of Canara, or Piney tallow. Various species of Dipterocarpus yield a substance like Balsam of Copaiva. D. levis, angustifolius, turbinatus, hispidus, zey- lanicus, yield wood-oil. Shorea robusta, a native of India, supplies the valuable timber called Sal. It yields the Dhoom or Dammar pitch, used for incense in India. Order 31.—CuLanaceg, the Chlenad Family. (Polypet. Hypog.) A small order, allied to Malvacez in having a 1-2-flowered involucre, and in having the stamens cohering at the base; while the zstivation is imbricate and resembles that of Ternstroemiaceze.—Trees or shrubs, with alternate stipulate leaves, found in Madagascar. Their proper- 452 TERNSTREMIACEZ. ties are unknown. ‘There are four genera enumerated, including pro- bably about 8 or 10 species, Hxamples—Sarcolena, Leptolena, Schizo- lena, Rhodolena. Order 32.—TERNSTREMIACEA, the Tea Family. (Polypet. Hypog.) Sepals 5 or 7, concave, coriaceous, deciduous, the innermost often the largest ; sestivation imbricated (fig. 289 c, p. 194). Petals 5, 6, or 9, often combined at the base. Stamens indefinite, hypogynous ; filaments free, or united at the base into one or more parcels ; anthers versatile, or adnate, dehiscing longitudinally. Ovary multilocular ; styles 2-7, Fruit either a capsule, 2-7 celled, opening by valves, or coriaceous and indehiscent. Seeds attached to the axis, few and large; albumen 0, or in very small quantity; embryo straight or bent, or folded back ; radicle next the hilum ; cotyledons very large (fig. 599, p. 335), often containing oil—Trees or shrubs, with alter- nate coriaceous, exstipulate leaves, which are sometimes dotted. They abound in South America, and many occur in India, while others inhabit China and North America, They do not occur in Australia and New Zealand. There are 32 genera and 260 species enumerated. The order has been divided into six tribes, founded on the following genera: Examples—l1. Rhizobola. 2. Marcgravia. 3. Ternstroemia. 4, Saurauja. 5. Gordonia. 6. Bonnetia. The most important plants of this order are those which yield Tea. Considerable discussion has taken place regarding the Tea plants ; some say that there is only one species; others, two; others, three. Fortune visited the black and green tea districts of Canton, Fokien, and Chekiang, and he says that the black and green teas of the north- ern districts of China are obtained from the same species or variety, viz. that cultivated in Britain under the name of Thea viridis ; while the black and green teas from the neighbourhood of Canton are made from the species or variety cultivated in this country under the name of Thea Bohea. Some make the Assam plant a different species, and thus recognise three, Thea Cantoniensis or Bohea, Thea viridis, and Thea Assamica. The quality of the tea depends much on the season when the leaves are picked, the mode in which they are prepared, as well as the district in which the plant grows. Green Tea contains more essential oil and tannin than Black Tea. The Green Teas include Twankay, Young Hyson, Hyson, Gunpowder, and Imperial; while the black include Bohea, Congou, Souchong, Oolong, and Pekoe. The teas of certain dis- tricts, such as Ankoi, have peculiar characters. In some instances teas are dyed by means of Isatis indigotica ; in other cases by Prussian blue, turmeric, and gypsum. Perfume is communicated to teas by means of Olea fragrans, Chloranthus inconspicuus, and Aglaia odorata, There is a bitter principle in tea called theine, which may be procured by adding a slight excess of acetate of lead to a decoction of tea, filtering hot, evaporating, and subliming. According to Dr. Stenhouse, OLACACEAi—AURANTIACE. 453 as 1 1b. of Green Hyson Tea gave 72 grains pure white Theine, and 2 coloured = 74 grains or 1°05 p.c. 8 oz. Black Congou gave 34°5 gr. pure, and 1°5 impure = 36 gr. or 1°02 p.c. 6 oz. of Black Assam Tea yielded 86 gr. or 1°37 p.c. 1 1b. of a cheap Green Tea, called Twankay, gave 69 gr. or 0°98 p.c. In 1874, the imports of tea into the United Kingdom amounted to 142,068,524 lbs., of which 127,323,630 lbs. were retained for home consumption. The tea plant is now largely cultivated in India, especially at Darjeeling and Saharunpore. The genus Camellia is prized on account of its showy flowers. There are numerous culti- vated varieties of Camellia japonica, many of which can endure the climate of Britain when trained on a wall with a southern exposure, or slightly protected. In China, Camellia Sasanqua, or Sasanqua tea, is cultivated on account of its flowers, which are said to impart fra- grance and flavour to other teas. Camellia oledfera yields a valuable oil. Souari or Butter Nuts are the produce of Caryocar butyrosum. The flowers of Marcgravia are occasionally furnished with bracts, which are folded, and united so as to form ascidia. The stem, root, and leaves of Marcgravia umbellata are regarded in the West Indies as diuretic. The leaves of Freziera theoides are used as tea in Panama. Order 33.—Oxacaceas, the Olax Family. (Polypet. Hypog.) Calyx small, gamosepalous, entire or toothed, often becoming finally large and fleshy ; estivation imbricated. Petals 3-6, hypogynous, free, or adhering in pairs by means of the stamens; estivation val- vate. Stamens hypogynous, some fertile, others sterile ; the former 3-10, alternate with the petals, the latter opposite to the petals; filaments compressed ; anthers innate, bilocular, with longitudinal dehiscence. Ovary 1-3-4 celled; ovules 1-3, pendulous from a cen- tral placenta ; style filiform; stigma simple. Fruit fleshy, indehis- cent, often surrounded by the enlarged calyx, unilocular, monospermal, Seed anatropal, pendulous; albumen copious, fleshy ; embryo small, at the base of the albumen.— Trees or shrubs, with simple, alternate, exstipulate leaves, which are, however, sometimes abortive. They are chiefly tropical or subtropical—being found in the East Indies, New Holland, and Africa, One only is known in the West Indies. A few are from the Cape of Good Hope. Little is known in regard to their properties. Olaw zeylanica has a fetid wood witha saline taste, and is employed in putrid fevers ; its leaves are used asa salad. There are 36 genera and 170 species enumerated. Hxvamples—Olax, Opilia, Icacina. Order 34, —AURANTIACES, the Orange Family. (Polypet. Hypog.) Calyx urceolate or campanulate, short, 3-5 toothed, withering. Petals 3-5, broad at the base, sometimes slightly coherent ; estivation imbricated. Stamens equal in number to, or a multiple of, the petals ; filaments flattened at the base, distinct or combined into one or more parcels ; anthers erect. Thalamus enlarged in the form of a 454 AURANTIACEA. ~ hypogynous disk, to which the petals and stamens are attached. Ovary free, multilocular ; style 1; stigma thickish, somewhat divided. Fruit a hesperidium, having a spongy separable rind, and pulpy sepa- rable cells (p. 314). Seeds anatropal, attached to the axis, solitary or several, usually pendulous, having the chalaza and raphe usually well marked ; perisperm 0; embryo straight; cotyledons thick and fleshy.—Trees or shrubs, usually conspicuous for their beauty, with alternate, often compound leaves, which are articulated with a petiole, usually winged (fig. 201, p. 85). They abound in the East Indies. Limonia Laureola is remarkable as the only plant of this family found near the summit of lofty mountains, where it is for some months of the year covered with snow. Some include this order in Rutacez, to which in many points it is allied. There are 13 genera and nearly 80 species enumerated. £xamples—Citrus, Limonia, Triphasia, The plants exhibit in every part receptacles of volatile oil, The oil abounds in the leaves and in the rind of the fruit. It is fragrant and bitter. The fruit has a more or less acid pulp, and the wood is generally compact. The Orange, Lemon, Lime, Citron, Shaddock, and Forbidden Fruit belong to this order. Citrus vulgaris yields the Bitter or Seville Orange, from the flowers of which an essential oil, called Neroli-oil, is procured, in the proportion of an ounce from 550 pounds of flowers. A similar oil is got from the flower of the Sweet Orange, Citrus Aurantium. The rind of the Bitter Orange is used in conserves. In the young state the fruit is sold under the name of Orangettes or Curacoa oranges. Orange- flower-water, as obtained from the flowers of the Bitter Orange, is employed as an anodyne. The chief kinds of Sweet Orange are the Common Orange, the Chinese or Mandarin Orange, the Maltese, and St. Michael’s. The last are the finest imported into Britain, and are distinguished by their smooth, thin rind. A single tree, it is said, will produce 20,000 good oranges. Their fruit is used medicinally, on account of the pulp, which contains sugar, mucilage, and citric acid. From the rind of the Sweet Orange, an oil, called Oil of Orange, is procured, which differs from Neroli-oil. A similar oil, but of inferior quality, is procured from the rind of the Seville Orange. Many look on the Bitter and Sweet Oranges as pro- duced by varieties of one species. The Bitter Orange tree is less than that yielding the Sweet Orange ; the petioles are more distinctly foli- aceous ; the flowers have a sweeter fragrance ; the rind of the fruit is darker and more bitter ; and its pulp more bitter and less saccharine. The Lemon, Lime, and Citron, are distinguished from oranges by their oblong form, their adherent rind, and a protuberance at the apex. Citrus Limonum yields the Lemon, the juice of which is antiscorbutic, and is used for cooling drinks and effervescing draughts, while the peel or rind, on account of the oil it contains, is employed as an aromatic and anthelmintic. A single tree will produce 8000 lemons. HYPERICACEA, 455 Citrus medica furnishes the Citron, which is larger than the Lemon, has a thicker and tuberculated rind, and a less acid pulp. The rind and juice may be applied to the same purposes as those of the Lemon. C. Bergamia is the Mellarosa or Bergamot, which is a variety of C. Limetia, the Lime. The Bergamot is less than the Lemon in size, and is more pyriform, while its colour is golden. The Lime is about half the size of the Lemon; its rind is thin, dense, and of a greenish-yellow colour, and its. taste is more bitter. Oil of Bergamot is the volatile oil of the rind, and 100 fruits are said to yield 2} ounces. Citrus acida is the East Indian Lime. Citrus Decumana furnishes the Shaddock; 0. paradisi, the Forbidden Fruit; 0. olive- formis, the Kumquat; and C. Pompelmos, the Pompelmoose fruit: What are called horned oranges and fingered citrons are produced by a separation or multiplication of the carpels. Sometimes small fruits are enclosed within the large one. In the navel-orange of Pernambuco abortive carpels are seen at the apex. gle Marmelos (Indian Bael) yields an excellent fruit. The halfripe fruit is used as a remedy for dysentery. From Feronia elephantum, a gum, like gum-arabic, is procured. Order 35.— Hyprricacrm, the Tutsan or St. John’s-wort Family. (Polypet. Hypog.) Sepals 4-5, separate or united, persist- ent, usually with glandular dots, unequal; estivation imbricated. Petals 4-5, oblique, often with black dots; sstivation contorted. Stamens hypogynous, o ; generally polyadelphous (fig. 347, p. 218), very rarely 10, and monadelphous or distinct; filaments filiform ; anthers bilocular, with longitudinal dehiscence. Carpels 2-5, united round a central or basal placenta; styles the same number as the carpels, usually separate ; stigmas capitate or simple. Fruit either fleshy or capsular, multilocular, and multivalvular, rarely unilocular. Seeds usually 00, minute, anatropal, usually exalbuminous ; embryo usually straight.—Herbaceous plants, shrubs or trees, with exstipu- late entire leaves, which are usually opposite and dotted. Flowers often yellow. They are distributed very generally over all parts of the globe, are found in elevated and low, dry and damp situations. They yield a resinous coloured juice which has purgative properties, and resembles gamboge. In the European species this yellow juice is in small proportion to the essential oil and the rest of the vege- table matter ; they have been used as tonics and astringents. Hyperi- cum hireinum is fetid. A gargle for sore throats is prepared in Brazil from Hypericum connatum. A decoction of the leave$ of Hypericum laxiusculum, or Allecrim brabo, is reputed in the same country to be a specific against the bite of serpents. Parnassia palustris, Grass of Parnassus, has remarkable gland-like bodies between the stamens (fig. 335, p. 210). These are probably an abortive state of the staminal organs. Lindley looks upon them as bundles of stamens, and hence 456 GUTTIFERZ OR CLUSIACEA,. places the genus among Hypericacex, while others refer the plant to the natural order Crassulacez. The stamens of Parnassia are irritable, and move towards the pistil in succession (p. 386). There are 17 known genera, and about 281 species. Hxamples—Hypericum, Elodea, Vismia, Parnassia. Order 36.—GutTtirER# or CLustacea, the Gamboge Family. (Polypet, Hypog.) Sepals 2-6-8, usually persistent, round, fre- quently unequal and coloured ; xstivation imbricated. Petals hypo- gynous, equal to, or a multiple of, the sepals. Stamens hypogynous, usually 00, rarely definite, free or variously united at the base ; fila- ments unequal in length ; anthers adnate, introrse or extrorse, some- times very small, occasionally unilocular, and sometimes with porous or circumscissile dehiscence. Thalamus forming a fleshy, sometimes 5-lobed disk. Ovary solitary, 1- or many-celled ; ovules either solitary and erect or ascending, or numerous and attached to central placentas ; style 0 or very short ; stigmas peltate or radiate. Fruit dry or fleshy, 1- or many-celled, 1- or many-seeded, either with septicidal dehiscence or indehiscent. Seeds definite, anatropal, or orthotropal, in a pulp, apterous and often arillate, with a thin and membranous spermoderm ; albumen 0; embryo straight ; cotyledons usually cohering.—Trees or shrubs, sometimes parasitical, with exstipulate, opposite, coriaceous, entire leaves, having a strong midrib, and lateral veins running directly to the margin. Flowers articulated with the peduncle, often unisexual by abortion. They are natives of tropical regions, more especially of South America; a few are from Madagascar and the continent of Africa. They generally require situations combining excessive heat and humidity. Authors enumerate 30 genera, including about 230 species. Hxamples—Clusia, Garcinia, Cambogia, and Calophyllum. The plants of this order yield a resinous juice, which is acrid, pur- gative, and has a yellow colour. Gamboge is one of the most im- portant products. It is procured from Garcinia Morella, var. pedicel- lata (G. Hanburyi of Hooker), a dicecious tree, with laurel-like foliage and small yellow flowers, found in Camboja, Siam, and in the southern parts of Cochin-China. Garcinia pictoria and Travancorica also furnish Gamboge. In commerce this drug occurs in the form of Pipe or Roll Gamboge, and of Lump or Cake Gamboge. Another kind of gamboge, called Coorg or Wynaad Gamboge, seems to be the produce of Garcinia elliptica. Gamboge is a powerful irritant, and in large doses acts as a poison, causing inflammation of thé mucous membrane. It is employed medicinally as a drastic and hydragogue cathartic. It is an excellent pigment. The resin of Tacamahaca is yielded by Calophyllum Calaba, An oil is obtained from the seeds of Calophyllum Inophyllum. Pentadesma butyracea is the Butter and Tallow-tree of Sierra Leone, so called on account of the solid oil which is furnished by the fruit. While an acrid resin is the product of ERYTHROXYLACEA—MALPIGHIACEZ. 457 most of the plants of the order, there are some parts in which the resin is either absent or elaborated in small quantity. Thus some of them produce fruits which are used as articles of diet. Garcinia Mangostana supplies the East Indian Mangosteen, which is said to be one of the finest known fruits; it resembles a middle-sized Orange, and is filled with a sweet and highly-flavoured pulp. Mammea americana gives a drupaceous fruit, called Mammee Apple, or Wild Apricot of South America. Its seeds are anthelmintic ; its flowers yield by distillation a stomachic spirit called Eau de Oréole; and a wine is obtained by fermenting its sap. Mesua ferrea yields a hard and durable timber. The Clusias are handsome trees, remarkable for the mode in which they send out adventitious roots. The fruit of Clusia flava, sometimes called Wild Mango, or Balsam-tree, yields a yellow juice like gamboge. Order 37, ERYTHROXYLACEA, the Erythroxylon Family. (Poly- pet. Hypog.) Sepals 5, united at the base, persistent ; xstivation imbricated. Petals 5, hypogynous, broad and with a small scale at the base, slightly contorted in estivation, Stamens 10, monadel- phous ; anthers erect, bilocular, with longitudinal dehiscence. Ovary 3-celled, two cells sometimes abortive ; styles 3, distinct or united ; stigmas 3 ; ovule single, pendulous, Fruit a 1-seeded drupe. Seed angular, anatropal; embryo in the axis of firm albumen, rarely exalbuminous ; cotyledons linear, flat, and leafy.—Shrubs or trees with alternate stipulate leaves. Flowers arising from numerous, im- bricated, scale-like bracts. Found chiefly in the West Indies and South America, The plants of the order have tonic, purgative, and narcotic qualities. The leaves of Erythroaylon Coca are used by the miners of Peru as a stimulant, like opium. They receive the name of Coca or Ipadu. They are chewed with a small mixture of finely- powdered chalk. The wood of some is of a bright red colour, and yields a dye. There are 3 known genera, and about 60 species. Example—Erythroxylon. ‘ Order 38.—Matriauiaces, the Malpighia Family. (Polypet. Hypog.) Sepals 5,islightly united, persistent, often glandular at the base ; eestivation imbricated. Petals 5, unguiculate, with convolute estivation, Stamens usually 10,. often monadelphous; anthers roundish, with a projecting process from the connective (fig. 371, p. 223 ; 374, p. 225). Ovary formed by 3 (rarely 2 or 4) carpels, more or less combined ; ovules solitary, with a long pendulous cord ; ~ styles 3, distinct or united. Fruit dry or fleshy, sometimes winged (fig. 562, p. 310). Seeds solitary, orthotropal, suspended, exalbumi- nous ; embryo straight or curved in various ways ; cotyledons foliace- ous or thickish (fig. 602, p. 338)—Trees or shrubs, sometimes climbing, with simple, opposite, or very rarely alternate, stipulate . leaves, without dots. Hairs, when present, peltate (fig. 89, p. 33). 458 ACERACEA—SAPINDACEA. Flowers either perfect or unisexual. They are inhabitants of tropical countries chiefly, and a great number of them are found in South America. Authors notice 50 genera, including 589 species. Hxamples —NMalpighia, Banisteria, Hiptage, Hirea, Gaudichaudia. Some of the woody plants of this order exhibit an anomalous for- mation of the stem, from the absence of annular rings and medullary rays, and the peculiar mode in which the bark is produced. This is shown in figs. 123, p. 61; 126, and 127, p. 62. Many of the plants are astringent. Some have stinging hairs (fig. 89, p. 33). The fruit of Malpighia glabro and of M. punicifolia is called Barbados Cherry, and is used as an article of dessert. Nitraria is a genus doubt- fully referred to this order; by some it is placed under the order Zygophyllacee, N, tridentata, found in the desert of Soussa, near Tunis, is said by some to be the true Lotus-tree of the ancient Lotophagi. Order 39.—AcERAcgEs, the Maple Family. (Polypet. Hypog.) Calyx divided into 5, rarely into 4 or 9 parts, with an imbricated estivation. Petals equal in number to the lobes of the calyx, with which they alternate, rarely wanting. Stamens generally 8, inserted on a hypogynous disk. Ovary free, 2-lobed, 2-celled ; ovules in pairs ; amphitropal, pendulous ; style 1; stigmas 2. Fruit, a samara (fig. 561, p. 310), composed of two winged carpels, each 1-celled with 1-2 seeds. Seeds erect, exalbuminous; embryo curved, with foliaceous cotyledons, and the radicle next the hilum.—Trees with opposite, simple, lobed or palmate, exstipulate leaves. Flowers often polyga- mous. They are confined chiefly to the temperate parts of HKurope, Asia, and North America. They yield a saccharine sap, from which sugar is sometimes manufactured. It is said that their juices become acrid as the season advances. The bark is astringent, and yields reddish-brown and yellow-coloured dyes. Acer saccharinum is the Sugar Maple of America, Acer Pseudo-platanus, the Sycamore or Great Maple (the Plane-tree of Scotland), acts well as a shelter in exposed places, as near the sea. Its sap is slightly saccharine. Its wood is used in machinery and for charcoal. The leaves are often covered with black spots, caused by the attack of a fungus, Rhytisma acerinum. There are 3 known genera, and 60 species, HExamples— Acer, Negundo, Dobinea. Order 40.—Sapinpacea, the Soapwort Family. (Polypet. Hypog.) Sepals 4-5, distinct or cohering at the base ; estivation imbricated. Petals 4-5, occasionally absent, hypogynous, sometimes naked, some- times with a glandular or scaly appendage inside ; estivation imbri- cated. Stamens usually 8-10, sometimes 5-6-7, very rarely 20 ; fila- ments free, or combined just at the base; anthers introrse. Thala- mus forming a fleshy or glandular disc, into which the stamens are often inserted. Ovary trilocular, rarely bi- or quadri-locular ; ovules anatropal, definite ; style either undivided or 2-3 cleft. Fruit either MELIACE. 459 fleshy and indehiscent, or samaroid, or capsular, and 2-3 valved. Seeds solitary, often arillate, exalbuminous ; embryo straight, curved, or spiral ; cotyledons incumbent; radicle next the hilum.—Trees or shrubs, sometimes climbing herbaceous plants, with alternate, some- times opposite, compound, rarely simple leaves, often marked with lines or pellucid dots. They are natives principally of South America and India. Africa contains many of them; they are wanting in the cold regions of the north. None are found wild in Europe. (In this order some include the Hippocastaneze or Horse-chestnuts, which are distinguished by their opposite leaves, and their two ovules in each cell, one ascending, the other suspended) (fig. 464, p. 258). Authors give 70 genera, including 600 species. Examples—Sapindus, Paullinia, Nephelium, Dodonza, Meliosma, Aisculus, Pavia. In this order are included many plants which yield edible fruits, and others which are poisonous. A saponaceous principle exists in certain species. The fruit of Sapindus Saponaria, under the name of Soap-berries, is used as a substitute for soap in the West Indies. The Longan and Litchi are excellent Chinese fruits, the produce of Nephe- liwm Longan and N. Litchi. The kernel of the Longan powdered is sometimes made into paper. Blighia or Cupania sapida yields the Akee fruit, the succulent arillus of which is used as food. Many of the Paullinias are poisonous. From the seeds of Paullinia sorbilis, however, the Guarana bread or Brazilian cocoa is prepared in Brazil. The seeds, after being dried and deprived of their white aril, are pounded and kneaded into a dough, which is afterwards made up into cakes or balls. This guarana contains a bitter crystalline matter called Guaranine, identical with Caffeine. The bark of Asculus Hippocastanum, Horse-chestnut, has been recommended as a febrifuge, and its seeds have been used as a substitute for coffee. The fruit and leaves of Alsculus ohiotensis, the Buck-eye or American Horse-chestnut, are said to be poisonous. Paullinia pinnata, and some other Sapin- dacee of Brazil, exhibit anomalous exogenous stems (fig. 124, p. 62). Ophiocaryon paradoxwm is the Snake-nut-tree of Demerara, and is so called on account of the embryo resembling a coiled-up snake. Order 41.—Metiacea, the Melia Family. (Polypet. Hypog.) Sepals 4-5, more or less united, with an imbricated estivation. Petals 4-5, hypogynous, sometimes cohering at the base, with a valvate or imbricated estivation. Stamens equal in number to the petals, or 2, 3, or 4 times as many; filaments combined in a long tube ; anthers sessile within the orifice of the tube. Disk often large and cup-shaped. Ovary single, multilocular, the cells often equal in number to the petals ; ovules usually anatropal, 1-2 in each cell ; style 1; stigmas distinct or,united. -Fruit baccate, drupaceous or capsular, multilocu- lar, or by abortion unilocular; when valves are present opening by loculicidal dehiscence. Seeds not winged ; albumen usually absent ; 460 CEDRELACEZ—AMPELIDEA OR VITACEA. embryo straight, with leafy cotyledons—tTrees or shrubs with alter- nate (occasionally opposite), exstipulate, simple, or pinnate leaves. They are chiefly found in the tropical parts of America and Asia. Under this order some include Humiriacex, which are distinguished by a prolonged fleshy connective (fig. 373, p. 225), albuminous seeds, and a slender embryo. Arnott includes Cedrelacez also under this order. There are about 29 known genera, and upwards of 240 species. Examples—Melia, Trichilia, Humiria. _ The plants of this order are bitter, tonic, and astringent. Melia In- dica,or Azadirachta, is used in India as a febrifuge, and its fruit yields an oil which is employed for domestic purposes, and as an antispas- modic. Jt is an ornamental tree, 40 or 50 feet high. Its Hindu- stanee name is Nim, and its Portuguese name is Margosa. Its bark is used as a tonic, under the name of Margosa bark. The root of Melia Azedarach, a native of China, is bitter and nauseous, and is used in North America as an anthelmintic. Oils are procured also from species of Trichila and Carapa (fig. 603, p. 338). A warm pleasant- smelling oil is prepared from the fruit of Trichilia speciosa, which in India is considered as a valuable external remedy in chronic rheuma- tism and paralytic affections. The bark of Carapa guineensis has repu- tation as an anthelmintic. The fruit called in the Indian Archipelago Langsat, is the produce of a species of Lansium. A fragrant balsam, called balsam of Umiri, is got from the trunk of Humiria floribunda. Order 42.—CrpRELAcE#, the Mahogany Family. (Polypet. Hypog.) Calyx 4-5-cleft, with imbricated estivation. Petals 4-5, with imbricated estivation. Stamens 8-10, united below into a tube, sometimes distinct, inserted into a hypogynous annular disc ; anthers bilocular, acuminated, with longitudinal dehiscence. Ovary usually 4- or 5-celled ; ovules anatropal, pendulous; style simple; stigma peltate. Fruit a capsule opening septifragally (fig. 546, p. 304; 547, p. 305). Seeds winged ; albumen thin or 0; embryo straight, erect ; cotyledons fleshy—Trees with alternate, pinnate, exstipulate leaves. They are found in the tropical parts of America and Asia. Authors enumerate 8 genera, including 24 species. Examples— Cedrela, Swietenia. The plants of this order are bitter, and have an aromatic fragrance. Swietenia Mahagoni supplies the well-known mahogany wood. Its bark, as well as that of Soymida febrifuga, called Rohun bark, and of Cedrela febrifuga, are used for the cure of intermittents. The wood of the tree is sometimes called Bastard Cedar. Chloroxylon Swietenia produces satin wood, and also yields a kind of wood-oil. Order 43.—AMPELIDE® or ViTacza, the Vine Family. (Fig. 692.) (Polypet. Hypog.) Calyx small, nearly entire (fig. 693 c). Petals 4-5, sometimes cohering above (fig. 693 p), inserted outside an annular hypogynous disk (figs. 693, 694 g); sestivation valvate. AMPELIDE OR VITACEA. 461 Stamens 4-5, opposite to the petals (figs. 693, 694. ¢), inserted on the disk ; filaments free, or united at the base; anthers ovate, versatile (fig. 694). Ovary 2-6-celled ; ovules erect, anatropal (fig. 695 0); style 1, very short ; stigma simple (695 s). Fruit pulpy and globular, not united to the calyx (fig. 696), sometimes 1-celled by abortion. Seeds 1 to 4 or 5, erect (fig. 697), with an osseous spermoderm, horny Fig. 695. Fig. 694. Fig. 693. Fig. 692. Fig. 699. Fig. 696. Fig. 698. Fig. 697. albumen (figs. 698, 699 p), and an erect embryo (fig. 698 e)——Climb- ing shrubs, having the lower leaves opposite, the upper ones alternate (fig. 239, p. 120). Flowers in racemes, which are often opposite the leaves ; floral peduncles sometimes becoming cirrhose. They inhabit the milder as well as the hotter parts of both hemispheres, and abound in the West Indies. There are 4 genera and 250 species. Ezxamiples —Vitis, Cissus, Leea. The plants of this order have generally acid leaves, and their fruit when ripe is saccharine. Vitis vinifera, the Grape Vine, belongs to this order. It is said to be a native of the shores of the Caspian, whence it was imported into Europe. The unripe fruit contains a harsh acid juice, called verjuice. It contains free citric, malic, and tartaric acids, along with bitartrate of potass. As grapes ripen, sugar, Fig. 692-699. Organs of fructification of Vitis vinifera, to illustrate the natural order Vitacee or Ampelidez. Fig. 692, Diagram of the flower, showing 5 sepals, 5 petals, 5, stamens opposite the petals on account of the non-development of one staminal row, a disk, and the ovary. Fig. 693. Flower showing the petals, p, detached at the base, and re- maining united above in a calyptra-like manner. c, Calyx. g, Glands forming a disk, e, Stamens, the filaments of which only are seen. Fig. 694. Flower after the petals have fallen. g, Glands of the disk. e, Stamens with versatile anthers. p, Pistil. Fig. 695. Vertical section of the flower. c, Calyx. , Petals. ¢, Filaments. o, Ovary, with 2 cells and their erect anatropal ovules. s, Stigma, Fig. 696. Globular pulpy fruit, uva, or grape, differing from a berry, in the calyx not forming part of the pericarp. It is by some called nuculanium. Fig. 697. The seed of the grape, with its osseous spermoderm en- closing a hard perisperm. Fig. 698. The seed cut vertically. ¢, The integument or sper- moderm. p, Perisperm, or albumen, which is horny. e, Erect embryo, with lanceolate cotyledons. Fig. 699. Horizontal section of the seed of the grape, about the middle, ¢, Integument or spermoderm. », Perisperm or albumen. 462 GERANIACEA. called Grape-sugar, is formed at the expense of the acids (pp. 164, 165). The vessels of the vine are large (fig. 63, p. 19), and the sap passes through them with great force and rapidity. When cut in spring the plant bleeds freely. The leaves of the vine, on account of their as- tringency, have been used in diarrhoea. In France its sap is a popular remedy for chronic ophthalmia, Raisins (uve passe), as found in the shops, are the produce of Spain and Asia Minor. Muscatel raisins are imported from Malaga, and are used for dessert ; Valencia raisins from Spain. The stoneless Sultana raisins, from Smyrna, are used for culinary purposes. In pharmacy Valencia raisins are used. In 1872, the consumption of raisins in Great Britain amounted to 617,418 ewt., value £1,149,337. The currants of the shops are the dried fruit of the Corinthian vine. The name currant in this case is a corruption of Corinth. Vitis vulpina yields the Fox-grapes of Rhode Island. The leaves of Cissus cordata and C. setosa are said to possess acrid pro- perties. The berries of the latter are acrid. Both leaves and fruit of Cissus tinctoria abound in a green colouring matter, which on exposure to air and light becomes blue, and is highly esteemed as a dye for cotton fabrics. Amypelopsis virginica, the Virginian creeper, is com- monly cultivated as a climbing plant. Order 44.—GERANIACEA, the Cranesbill Family. (Polypet. Hypog.) Sepals 5, persistent, more or less unequal (figs. 338, p. 213; 351 ce, p. 306), one sometimes spurred at the base (Pelargonium) ; estivation imbricated. Petals 5 (or by abortion 4), unguiculate, with contorted estivation (figs. 338, p. 213; 379 pp, p. 228). Stamens mona- delphous, hypogynous (figs. 338, p. 213 ; 379 e, p. 228), twice or thrice as many as the petals, some occasionally abortive. Ovary of 5 carpels, placed round an elongated axis (fig. 338 t, p. 213); ovules pendulous, solitary ; styles 5, cohering round the axis or carpophore (fig. 338, p. 213), Fruit formed of 5 one-seeded coccoons, terminated each by an indurated style, which curls upwards, carrying the coccus or pericarp with it (fig. 551, p. 306), Seeds exalbuminous, solitary, with a curved folded embryo, and leafy, convolute, and plaited cotyledons (fig. 607, p. 339).—Herbs or shrubs, with simple, stipulate leaves, which are either opposite, or alternate with peduncles opposite to them. They are distributed over various parts of the world. The species of Pelar- gonium abound at the Cape of Good Hope. The species of Geranium proper have regular flowers without spurs. Authors mention 7 genera, including, after separating hybrids, about 300 species. Examples— Geranium, Pelargonium. The name Cranesbill is derived from the long beak-like prolonga- tion of the axis, or what is called the carpophore (p. 240). The plants of this order are astringent and aromatic. The root of Geranium macu- latum receives the name Alum root, in consequence of being a very powerful astringent. The tuberous or moniliform roots of some, such VIVIANIACEZ—LINACEA, 463 as Pelargonium triste (fig. 103, p. 41) are eatable. ‘The root-stock of Geranium oblongatum, called the yellow geranium, is used by the natives of Namaqualand as an article of food. The species of Pelar- gonium are remarkable for the beauty of their flowers. By the art of the gardener, and by hybridisation, many fine varieties of Pelargonium have been produced. Order 45.—Vivian1ace&, the Viviania Family. (Polypet. Hypog.) Sepals 5, united. Petals 5, hypogynous, unguiculate, persistent, with twisted zstivation. Stamens 10, hypogynous ; filaments free ; anthers bilocular, opening longitudinally. Ovary free, 3-celled; stigmas 3. Capsule 3-celled, 3-valved, loculicidal ; seeds, 2 in each cell, with a curved embryo lying among fleshy albumen.—Herbaceous or suffruti- cose plants, with opposite or verticillate exstipulate leaves. All the members of this order which have yet been discovered inhabit Chili and South Brazil. They have no properties of importance. Genera 2 ; species 8. Hxamples—Viviania, Czsarea. Order 46.—Linacz4, the Flax Family. (Polypet. Hypog.) Sepals 3, 4, or 5, persistent, with an imbricated estivation. Petals 3, 4, or 5, fugitive, unguiculate, hypogynous, with a twisted estivation. Sta- mens equal to the petals and alternate with them (with intermediate teeth or abortive stamens), arising from a hypogynous annular disk ; anthers ovate, erect. Ovary with as many cells and styles as sepals, seldom fewer ; stigmas capitate ; ovules anatropal, pendulous. Fruit a multilocular capsule, pointed generally with the indurated base of the styles ; each loculament or cell more or less completely divided by a spurious dissepiment, arising from the dorsal suture, and opening by two valves at the apex. Seeds solitary in each spurious cell, com- pressed, pendulous ; albumen ‘usually in small quantity, sometimes 0 ; embryo straight; cotyledons flat; radicle next the hilum.—Annual and perennial plants, with exstipulate, simple, entire leaves, which are usually alternate. Many species,of Linum have showy flowers, the colours being blue, yellow, and crimson. Linum grandiflorum, from the north of Africa, has a beautiful crimson flower. They are scattered over the globe, but are said to be most abundant in Europe and in the north of Africa, By some authors the order is associated with Geraniacez, from which it differs in its unbeaked fruit and exstipulate leaves, as well as the absence of joints in the stem. There are 4 genera, comprising about 90 species. Haxamples—Linum, Radiola. The plants yield mucilage and fibre. Flax, which consists of xylem or bast fibre, is procured from the inner bark of the stalk of Linum usitatissimum, by the process of steeping and stripping off the bark. Linen and cambric are prepared from it. The flax plant is supposed to have been originally a native of Egypt, and mummy. cloth has been shown to be formed of linen. The integument of the seeds is mucilaginous, and an infusion of them in boiling water is used 464 BALSAMINACEH—OXALIDACEA, as a demulcent and diuretic. The cotyledons of the seeds are olea- ginous, and by expression yield Linseed oil, which has the property of drying and hardening into an elastic varnish on exposure to the air. It is used medicinally for burns, mixed with lime water. After expressing the oil a cake remains, called oil-cake, which is used for fattening cattle. The powdered cake receives the name of linseed meal, and is commonly used for poultices. Another species of Linum, called L. catharticum, has purgative properties, which seem to depend on the presence of an acrid bitter matter, called Linin, Linum sela- ginoides is considered in Peru bitter and aperient. Order 47.—BatsaMInaces, the Balsam Family. (Polypet. Hypog.) Sepals 5, irregular, deciduous, the two inner and upper connate, coloured, the lower (odd) sepal spurred (fig. 640, p. 366); estivation imbricated. Petals alternate with the sepals, usually 4, in conse- quence of 1 being abortive, often more or less irregularly united ; estivation convolute. Stamens 5. Ovary 5-celled; ovules usually numerous, stigma sessile, more or less 5-lobed. Fruit a 5-celled capsule, opening septifragally, by 5 elastic valves. Seeds usually numerous, suspended, exalbuminous, with a straight embryo, and radicle next the hilum. —Succulent herbaceous plants with watery juice, having simple, opposite, or alternate, exstipulate leaves, and axillary irregular flowers. They inhabit chiefly the East Indies, and are remarkable for the force with which the seed-vessels open when ripe. The valves give way on account of the osmose which goes on in the cells, and they then curl up in a peculiar manner (pp. 15, 344). They have usually showy flowers, but their properties are unimportant. Lindley mentions 2 genera, including 136 species. Examples—Im- patiens, Hydrocera. Order 48.— Oxatipaces, the Wood-sorrel Family. (Polypet. Hypog.) Sepals 5, equal, sometimes cohering slightly at the base, persistent, imbricate in estivation. Petals 5, equal, unguiculate, hypogynous, with a twisted estivation. Stamens 10, more or less monadelphous, in 2 rows ; those opposite the petals being longer than those in the outer row ; anthers erect, bilocular, Ovary usually quin- quelocular ; styles filiform, distinct ; ‘stigmas capitate or slightly bifid. Fruit capsular, membranous or fleshy, usually 5-celled, and when dehiscent 5-10 valved. Seeds few, anatropal, albuminous, attached to a central placenta, sometimes with a peculiar elastic integument ; embryo straight, as long as the fleshy albumen, with a long radicle and leafy cotyledons. —Herbs, undershrubs, or trees, with alternate, rarely Opposite compound (occasionally simple) leaves, which are generally without stipules, They are found in the hot as ‘well as the temperate parts of the world, and are abundant in North America and at the Cape of Good Hope. The shrubby species are confined to the hotter parts of the world. In some cases phyllodia, or winged petioles, occupy TROPAOLACEA?—PITTOSPORACEA. 465 the place of leaves. The genus Hugonia is placed by some in the order Linacex, along with Roucheria. There are about 6 known genera, and upwards of 230 species, Zxamples—Oxalis, Averrhoa, Hugonia. They are often acid in their properties. Some of them yield esculent roots. Oxalis Acetosella, common Wood-sorrel, receives its name from its acid taste. It contains binoxalate of potash, which is sometimes called the salt of sorrel, and at other times the essential salt of lemons. The plant has been used as a refrigerant and antiscorbutic. Its leaves are trifoliate, and some have considered it to be the true Shamrock, in consequence of being in flower about the period of the year when St. Patrick’s day occurs. Some of the oxalises, as 0. sen- sitiva, have sensitive leaves, and experiments have been made in regard to their closing and opening by Morren (p. 377). Ouxalis crenata, esculenta, and Deppei, yield tubers, which have been used as a substi- tute for potatoes. The acid fruits of Averrhoa Bilimbi and Carambola are used in the East Indies as food. Order 49.—TropxoLacem, the Indian Cress Family. (Polypet. Hypog.) Sepals usually 5, the upper spurred (fig. 299, p. 198) ; estivation slightly imbricate. Petals often 5, hypogynous, more or less unequal, sometimes abortive (fig. 641, p. 366) ; cestivation con- volute. Stamens 8 or 10, seldom fewer, free, almost perigynous ; anthers bilocular, innate. Ovary triquetrous, composed of 3-5 carpels, with a single style, and 3-5 acute stigmas; ovules solitary, often pen- dulous. Fruit indehiscent, usually composed of 3 pieces. Seeds exalbuminous, with a large embryo, which has thick, often united, cotyledons, and a radicle next the hilum. — Herbaceous trailing or twining plants, having a delicate texture, with alternate exstipulate leaves, and axillary, often gay, flowers. They are natives of the tem- perate parts of America, and are extensively cultivated on account of their showy yellow, orange, scarlet, and occasionally blue flowers. The free spur of Tropzeolum represents the adherent spur of Pelar- gonium. They have more or less pungency in their fruit, which is used as a cress. The unripe fruit of Tropwolum majus, common In- dian Cress, or Garden Nasturtium, has been pickled, and used as capers, LIMNANTHACEZ are included by some in this order. They are charac- terised by regular flowers, valvate sepals, glands alternating with the petals, stamens double the number of the petals, carpels not beaked, indehiscent, separating from the axis, ovules solitary, with an inferior micropyle. ‘The species are found in North America, Limnanthes is a Californian genus, with showy flowers. Their roots are sometimes eaten. Genera 4, including 40 species. Hzample, Tropeolum, Floer- kea, Limnanthes. Order 50.—Prirrosporaces, the Pittosporum Family. (Polypet, Hypog.) Sepals 4 or 5, deciduous ; distinct or partially united ; zsti- vation imbricated, Petals 4 or 5, sometimes slightly cohering, with 2H 466 ZYGOPHYLLACE. imbricated estivation. Stamens 5, distinct, alternate with the petals. Ovary single, 2-5-celled ; style 1; stigmas 2-5, equal in number to the placentas. Fruit capsular or berried, with many-seeded cells, which are sometimes incomplete ; dehiscence loculicidal. Seeds often enveloped in a glutinous or resinous pulp, anatropal, with a minute embryo lying in fleshy albumen ; radicle long ; cotyledons very short. —Trees or shrubs, with simple, alternate, exstipulate leaves, and flowers occasionally polygamous. Some place the order next Tremandracex and Bixacee. They are found chiefly in Australia. Many of them are resinous, and, in some instances, the berries are eaten. Bursaria spinosa is called native Box and native Myrtle ,in Van Diemen’s Land. Authors mention 9 genera, including 90 species. Lxamples— Pittosporum, Billardiera, Sollya, Bursaria. Order 51.—ZyeorHytLaces, the Guaiacum Family. (Polypet. Hypog.) Calyx 4-5-parted, with convolute zstivation. Petals alter- nate with the calycine segments, estivation imbricated. Stamens twice as many as the petals; filaments dilated at the base, usually arising from scales (fig. 345, p. 217). Ovary simple, 4-5-celled ; divisions occasionally formed by spurious dissepiments (figs. 534, 535, p. 300). Ovules 2 or more in each cell, usually pendulous ; style simple, 4-5-furrowed ; stigma simple, or 4-5-lobed. Fruit capsular or rarely fleshy, with 4-5 angles or wings, 4-5-valved, either opening by loculicidal dehiscence, or indehiscent. Seeds few, usually with whitish albumen, sometimes exalbuminous; embryo green, with foli- aceous cotyledons and a superior radicle.—Herbs, shrubs, or trees, with opposite, stipulate, usually compound leaves, which are not dotted, and hermaphrodite flowers. They occur in various parts of the world, chiefly in warm extra-tropical regions, as in the south of Europe, America, Africa, and India. The order has been divided into two sections :—1. Zygophyllez, having albuminous seeds. 2. Tri- bulez, having exalbuminous seeds. Authors mention 10 genera, comprising 60 species. xamples—Zygophyllum, Guaiacum, Tribulus. Some of the plants abound in a stimulant resin, which pervades the wood and bark; others are bitter and acrid. The medicinal species are used as sudorifics. Zygophyllum Fabago is called the Bean- caper, on account of its flowers being used as a substitute for capers. The plant is said to act as a vermifuge. Guaiacwm officinale is a beautiful West Indian tree, the wood of which, commonly called lignum-vitee, is prized for its hardness. The alburnum is of a greyish- yellow colour, while the duramen is greenish-black. The fibres of the wood are remarkable for their direction, being cross-grained, in conse- quence of one layer crossing another diagonally. It yields a resinous matter known as the resin of Guaiac, or Gum-guaiac. This resin exudes spontaneously, or it may be procured by incisions, or by the application of heat. A solution of the resin in alcohol, when applied RUTACEA, 467 to the fresh cut surface of a potato, gives rise to a blue colour. Both the wood and the resin are used medicinally on account of their stimulant diaphoretic properties. In decoction and tincture they are administered in cutaneous and syphilitic diseases. Guatacum sanctum from Mexico and the Bahamas also supplies Guaiac resin, and is sometimes used medicinally on the continent. Tribulus terrestris is a prickly plant which grows in the Hast, and is found in Palestine. Some suppose that the Hebrew word 1755, dardar, translated thistle in the Old Testament, and re/Sodos, translated thistle in the New Testament, refers to this plant (figs. 534, 535, p. 300). Order 52.—Rutaces, the Rue Family. (Polypet. Hypog.) See figs. 632, 633, p. 364. Calyx having 4-5 segments, with an imbricated estivation. Petals alternate with the divisions of the calyx, distinct, or cohering below into a spurious gamopetalous corolla, rarely wanting ; estivation either contorted or valvate. Stamens equal in number to the petals (fig. 632, p. 364), or twice or thrice as many (rarely fewer by abortion or non-development) (fig. 633, p. 364), usually hypogy- nous, but in some instances perigynous. Between the stamens and ovary there is a more or less complete cup-shaped disk, which is either free or united to the calyx. Ovary sessile or supported on a gyno- phore (fig. 416, p. 239), its carpels equal to the petals in number or fewer ; ovules 2, rarely 4 or more in each carpel; styles adherent above (fig. 416, p. 239); stigma simple or dilated. Fruit capsular, its parts either combined completely or partially ; seeds solitary or in pairs, albuminous or exalbuminous ; embryo with a superior radicle. —Trees or shrubs, with exstipulate, opposite, or alternate leaves, usually covered with pellucid resinous dots (figs. 92, p. 35; 95, p. 36), and hermaphrodite flowers. The order has been subdivided into two sub-orders :—1. Rutez, with albuminous seeds, and the fruit with sarcocarp and endocarp combined. 2. Diosmez, with exalbuminous seeds, and a 2-valved endocarp, which dehisces at the base, and when the fruit is ripe separates from a 2-valved sarcocarp. Rutez are found chiefly in the southern part of the temperate zone, as in the south of Europe, while Diosmeze abound at the Cape of Good Hope and in Australia. Authors mention 44 genera and 430 species. Examples— Ruta, Dictamnus, Diosma, Barosma, Correa, Boronia, Zieria, Pilocarpus. The plants are remarkable for their peculiar odour, which is very powerful and penetrating. Many have antispasmodic properties, while others are bitter, and act as febrifuges and tonics. The leaves and unripe fruit of Ruta graveolens, common or garden Rue, are used in medicine as stimulant, antispasmodic, anthelmintic, and emmen- agogue. They emit when bruised a strong and peculiar oppressive odour, and have a bitter and acrid taste. By distillation with water they yield a yellow acrid volatile oil, which is their active constituent. The leaves of various species of Barosma, especially B. crenulata, 468 XANTHOXYLACEAI—SIMARUBACEZ. serratifolia, and betulina, are used in medicine under the name of Buchu. They contain a yellowish volatile oil, having a powerful odour, and they have been used as stimulants and antispasmodics, They are prescribed in catarrh of the bladder. Jaborandi, a sudorific and sialagogue from Pernambuco, appears to be the produce of a species. of Pilocarpus. Galipea Cusparia (G. officinalis, or Bon- plandia trifoliata), a plant found in Venezuela, supplies the Angos- tura bark, which is used as a tonic and febrifuge. The bark is im- ported by way of Trinidad. On the continent Angostura bark is sometimes adulterated with the poisonous bark of Strychnos Nux- vomica. Some of the species of Dictamnus, such as D. Frasinella, False Dittany, abound in volatile oil to such a degree that the atmo- sphere around them becomes inflammable in hot, dry, and calm weather. The Correas are remarkable for their gamopetalous corolla, The leaves of some of the species have been used for tea in Australia. Order 53, —XANTHOXYLACEA or ZANTHOXYLACE#, the Xanthoxy- lon Family. (Polypet. Hypog.) Flowers unisexual. Calyx in 3, 4, or 5 segments, with imbricated estivation. Petals the same num- ber, rarely 0, usually larger than the calyx ; sestivation imbricated or convolute. Stamens as many, or twice as many, as the petals, not developed in the female flowers. Ovary consisting of as many carpels as there are petals (sometimes fewer), the carpels being either completely or partially united (fig. 414, p. 238); ovules 2, rarely 4, in each carpel; styles more or less combined (fig. 414 s, p. 238). Fruit baccate or membranous, sometimes of 2-5 cells, sometimes of several drupes, or 2-valved capsules, the fleshy sarcocarp of which is partially separable from the endocarp. Seeds solitary or in pairs, pen-. dulous ; embryo lying within fleshy albumen ; radicle superior ; coty- ledons ovate, flat.—Trees or shrubs, with exstipulate, alternate, or opposite leaves, having pellucid dots. They exist chiefly in the tropical parts of America. Authors enumerate.24 genera, including 160 species. ELxamples—Xanthoxylon, Toddalia, Ptelea. The plants yield a volatile oil, which is aromatic and pungent. Some are diaphoretic in their properties, others are febrifugal and tonic. The pungency of species of Xanthoxylon has caused them sometimes to be denominated peppers. Xanthoxylon fraxinewm, or prickly ash, acts as a sialagogue. X. cartbeum has a bitter and febri- fugal bark. The bitter principle secreted by many of the plants of this order is called Xanthopicrine. Toddalia aculeata, a prickly climb- ing plant of the Indian Peninsula, the Mauritius, and Southern China, furnishes a pungent aromatic root. The bark of the root is used in India as a stimulating tonic. It was formerly known in Europe as Radix indica Lopeziana. Order 54.—SimaRuBAcEs, the Quassia and Simaruba Family. (Polypet. Hypog.) Flowers usually hermaphrodite. Calyx in 4 or 5 OCHNACEA. 469 divisions ; estivation imbricated. Petals 4 or 5, spreading or conni- vent into a kind of tube; estivation twisted. Stamens twice as many as the petals ; filaments arising from scales. Ovary 4-5-lobed, 4-5-celled, supported on a gynophore ; ovules solitary ; styles simple ; stigma 4-5-lobed. Fruit indehiscent, consisting of 4 or 5 drupes arranged round a common receptacle. Seeds anatropal, pendulous ; embryo exalbuminous.—Trees or shrubs, with exstipulate, alternate, usually compound leaves without dots. They are found in the tropical parts of America, Asia, and Africa. Authors give 30 genera, and 112 species. Haxamples—Simaruba, Quassia, Picreena, All the plants of the order are intensely bitter. Quassia wood was originally the product of Quassia amara, a tall shrub, never above 15 feet in height, inhabiting Surinam, Guiana, and Colombia. It is a very ornamental plant, and has remarkable pinnate leaves, with winged petioles. In their early state the leaves seem to be simple, but in the progress of growth two or more contractions take place, at each of which two leaflets appear, the pairs being separated by a winged midrib,—a continuation of the petiole. This Surinam Quassia does not appear to be exported now, and it is not met with in English trade. The Quassia of the shops is the wood of Picrena excelsa, a very large forest tree, attaining a height of nearly 100 feet, growing in Jamaica and other West Indian islands, where it is called Bitter Ash, and Bitter Wood. The quantity shipped from Jamaica in 1871 was 56 tons. Quassia is used medicinally, in the form of infusion and tincture as a tonic and anthelmintic. It acts as a narcotic poison on flies and other insects. Although prohibited by law, it is fre- quently employed by brewers as a substitute for hops. The bitterness of Quassia is said to be owing to a crystalline principle called Quas- sin. The bark of the root of Simaruba amara or officinalis, a tree found in Cayenne and in the West Indies, is used as a bitter tonic and astringent, more especially in the advanced stages of diarrhcea and dysentery. Brucea antidysenterica was at one time erroneously supposed to furnish false Angostura bark. It has properties similar to those of Quassia. The bark of Samadera indica is bitter and tonic, and contains a principle like Quassia. Order 55.—Ocunaces, the Ochna Family. (Polypet. Hypog.) Sepals 5, persistent, imbricated in estivation. Petals equal to, or twice as many as the sepals, deciduous, spreading, imbricated in esti- vation, Stamens 5, opposite the sepals, or 10, or indefinite ; filaments persistent, attached to a hypogynous disk; anthers bilocular, innate, opening by pores, or longitudinally. Carpels as many as the petals, seated on an enlarged gynobase (thecaphore) ; ovules erect or pendu- lous, styles united into one. Fruit gynobasic, consisting of several succulent, indehiscent, monospermous éarpels. Seeds anatropal, usually exalbuminous ; embryo straight; radicle short; cotyledons thick.— 470 CORIARIACEZ—STACKHOUSIACEA. Undershrubs or trees, with alternate, simple, stipulate leaves, and pedicels articulated in the middle. They grow in tropical countries, and are remarkable for the large succulent prolongation of the recep- tacle to which the carpels are attached. They fare generally bitter, and some of them are used as tonics. Genera, 12; species, 140. Examples—Ochna, Gomphia, Godoya. Order 56.—Cor1arracea, the Coriaria Family. (Polypet. Hypog.) Flowers unisexual. Calyx campanulate, 5-parted ; zestivation imbri- cate. Petals alternate with the calycine segments, very small, fleshy, with a keel on the internal surface. Stamens 10 (fig. 636, p. 365) ; filaments filiform, distinct; anthers dithecal, oblong. Ovary com- posed usually of 5 carpels, attached to a thickened receptacle or gyno- base, 5-celled ; ovules solitary, pendulous; style 0; stigmas 5, long and glandular. Fruit, consisting of 5 monospermous, indehiscent crustaceous carpels, enclosed by the enlarged petals. Seeds pendulous, anatropal, exalbuminous ; embryo nearly straight ; cotyledons fleshy ; radicle short and blunt.—Shrubs with opposite square branches, oppo- site, simple, ribbed leaves, and scaly buds. They are found in small numbers!in the south of Europe, South America, India, and New Zealand. Some of them are poisonous. ‘The leaves of Coriaria myrti- folia have been employed to adulterate Alexandrian Senna on the Continent. The leaves are known from those of true Senna by being 3-ribbed, and by wanting the inequality at their base which charac- terises true Senna. The leaves are used for dyeing black, and an in- fusion of them gives a dark-blue with sulphate of iron. Coriaria rusct- folia is the Toot or Tutu plant of New Zealand, the seeds and young shoots of which are narcotico-acrid poisons. Genus, 1; species, 5. Example—Coriaria. Sub-class II. —CatycirLor#&. In this Sub-class are included the polypetalous orders of Jussieu, in which the stamens are not hypogynous, as well as some mono- petalous and diclinous orders. A calyx and corolla are present, in other words, the plants are dichlamydeous ; the petals are distinct or united, and the stamens are either attached to the calyx, and free from the ovary, or they are placed above the ovary,—being perigynous or epigynous. This sub-class, along with Thalamiflore, comprises the dialypetalee of Endlicher. There are also included in it gamopetalous plants in which the ovary is inferior. Section L—Potypretat#. Petals separate, stamens perigynous or epigynous. Order 57.—SrackuHoustace#, the Stackhousia Family. (Poly- pet. Perigyn.) Calyx, 5-cleft, equal, with an inflated tube. Petals 5, equal, inserted at the top of the tube of the calyx, claws of the CELASTRACEZ, 471 petals united, limb narrow and stellate. Stamens 5, unequal, attached to the tube of the calyx. Ovary superior, 3-5-celled, cells partially distinct ; ovules solitary, erect ; styles 3-5, sometimes united at the base; stigmas simple. Fruit consisting of 3-5 indehiscent pieces, which are sometimes winged, and are attached to a central persistent column. Seeds anatropal ; embryo long, erect, in the axis of fleshy albumen.—Shrubs with simple, entire, alternate, stipulate leaves, found chiefly in Australia, and not possessing any marked properties. Genus, 1; species, 20. Hxample—Stackhousia, Order 58.—CrLAsTRACEs, the Spindle-tree Family. (Polypet. Perigyn.) Sepals 4-5 imbricated in estivation. Petals 4-5 on a fleshy disk surrounding the ovary, estivation imbricated. Stamens alternate with the petals; anthers erect. Disk large, flat, and ex- panded, surrounding the ovary to which it adheres. Ovary superior, 2-5-celled ; ovules ascending, one or numerous, attached to the axis by _ a short funiculus, Fruit either a 2-5-celled capsule, with loculicidal dehiscence, or drupaceous. Seeds one or many in each cell, anatropal, usually ascending, and sometimes arillate (figs. 577, 578, p. 328) ; albumen fleshy ; embryo straight, with flat cotyledons and a short radicle.—Small trees or shrubs, with simple, alternate, rarely opposite leaves, and small deciduous stipules. They inhabit the warm parts of Europe, North America, and Asia, and many are found at the Cape of Good Hope. Hippocrates are arborescent or climbing shrubs, found chiefly in South America. The order contains 39 known genera and 400 species. It has been divided into two tribes :—1. Celastreze, with 4-5 stamens inserted on the margin of the disk, filaments subulate, seeds albuminous. 2. Hippocrateze with, usually, 3 stamens inserted on the face of the disk, filaments flattened, seeds exalbuminous. Examples—Celastrus, Euonymus, Catha, Eleodendron, Hippocratea. The plants of the order have subacrid properties, and the seeds of some yield a useful oil. Those of Celastrus nutans or paniculatus are said in India to be of a stimulant nature, and to be used as a remedy in the disease called Beriberi. Some of the species of Celastrus, as C. venenatus, are reckoned poisonous. The seeds of Huonymus, Spindle- tree, are surrounded by an aril, or rather arillode, which is considered as a prolongation from the exostome (figs. 577, 578, p.328). In some of the species the capsules are crimson, and with the bright scarlet arillodes, they present a very showy appearance when the fruit is ripe. The bark of Huonymus tingens furnishes a yellow dye, which is used for marking the tika on the forehead of the Hindoos. It is also considered useful in diseases of the eye. The young shoots of Euonymus euro- peus, when charred, are used to form a particular kind of drawing- pencil ; its fruit and inner bark are said to be purgative and emetic. The young shoots of Catha edulis furnish the Arabian drug called Kat, which is used as a stimulant. The fruit of Salacia pyriformis, a native 472 STAPHYLEACEZ—RHAMNACEZ. of Sierra Leone, is about the size of a Bergamot Pear: its flavour is rich and sweet. The nuts of Hippocratea comosa are oily and sweet ; it is called, in the French West Indian Islands, Amandier du Bois. Order 59.—SrapHyLuaces, the Bladder-nut Family. (Polypet. Perigyn.) (Fig. 638, p. 366.) Sepals 5, united at the base, coloured. imbricated in estivation. Petals 5, alternate, with an imbricated estivation. Stamens 5, alternate with the petals. Disk large and urceolate. Ovary 2-3-celled, superior ; ovules usually ascending ; styles, 2-3, cohering at the base. Fruit membranous or fleshy, inde- hiscent or opening internally, often partly abortive. Seeds anatropal, roundish, truncate at the hilum, with a bony testa ; albumen generally 0; embryo straight, with thick cotyledons and a small inferior radicle. —Shrubs with opposite, pinnate leaves, having stipules and stipels. By many authors they are included under the last order. The plants are found in Europe, America, and Asia. Some are subacrid, while others are bitter and astringent. The species of Staphylea receive the , name of bladder-nut, on account of their inflated bladder-like pericarp. They are cultivated as handsome shrubs. Three known genera are enumerated and 14 species. Example—Staphylea. Order 60.— Ruamnacea#, the Buckthorn Family. (Polypet. Perigyn.) Calyx 4-5-cleft, valvate in estivation. Petals distinct, hooded or convolute, inserted into the throat of the calyx, sometimes 0. Stamens definite, opposite the petals. Disk large, fleshy, flat or urceolate. Ovary superior or half superior, 2-3- or 4-celled ; ovules solitary, erect, anatropal. Fruit fleshy and indehiscent, or dry and separating into three parts. Seeds erect ; albumen fleshy, rarely 0 ; embryo about as long as the seed, with a short inferior radicle and large flat cotyledons ; raphe dorsal or lateral—tTrees or shrubs, often spiny, with simple, alternate, rarely opposite leaves, and minute stipules. They are generally distributed over the globe, and are found both in temperate and tropical regions. There are 37 genera, and 430 species enumerated. Examples—Rhamuus, Ceanothus, Phy- lica, Pomaderris. Many of the plants of the order have active cathartic properties. Some, however, yield edible fruit, and others are tonic and febrifugal. Rhamnus catharticus, common or purging Buckthorn, is a European shrub, the black succulent fruits or berries of which are used as a hydragogue cathartic in cases of dropsy. The greenish juice becomes gradually red by the formation of acetic acid in it. It may be pre- served unchanged in the form of syrup. When mixed with lime and evaporated to dryness, it forms the colour called sap-green. The fruit of Rhamnus Frangula, Black Alder, is emetic and purgative. The wood supplies charcoal for gunpowder, and crayons for artists. The berries of Rhamnus infectorius, as well as those of other species, are known by the name of French berries. They have been used for ANACARDIACEA, 473 dyeing yellow. The fruit of many species of Zizyphus is used for food; Zizyphus Jujuba supplies the fruit called Jujube; and the Lotus, or Lote-bush of the classics, whence the Lotophagi were named, is Zizyphus Lotus, A kind of Scinde lac is found on Zizyphus Jujuba, Paliurus aculeatus, Christ’s-thorn, is common in the hedges of Judea. Ceanothus Americanus is used in America as an astringent, and its leaves, under the name of New Jersey Tea, have been used as a sub- stitute for tea. The leaves of Sageretia theezans are used for the same purpose by the poorer classes in China, Phylica arborea is a tree found in the island of Tristan d’Acunha, and also on Amsterdam Island in the South Indian Ocean, the two islands being separated by 5000 miles of ocean, and being nearly in the same latitude. Order 61.—ANACARDIACES, the Cashew-nut Family. (Polypet. Perigyn.) Flowers usually unisexual. Calyx usually small and per- sistent, with 5, or sometimes 3-4-7 divisions. Petals equal in num- ber to the calycine divisions, perigynous, sometimes 0 ; imbricated in estivation. Stamens either equal to the petals in number and alter- nate with them, or twice as many or more; filaments distinct or cohering at the base, usually perigynous. Disk fleshy, annular or cup-shaped, sometimes inconspicuous. Ovary single, rarely 5 or 6, free or adhering to the calyx, 1-celled ; ovule solitary, attached by a funiculus to the bottom or along the side of the cell; styles 1-3, occasionally 4; sigmas 1-3 or 4. Fruit usually drupaceous and inde- hiscent. Seed ascending or frequently pendulous, from the adherence of the funiculus to the angle of the cell, exalbuminous ; radicle inferior or superior, sometimes curved suddenly back ; cotyledons thick, fleshy, or leafy.—Trees or shrubs, with a resinous, often caustic juice, and alternate leaves without dots. The order is a subdivision of the Terebinthacese of Jussieu. The natural order SABIACEa, embracing East Indian plants, is considered by some as a tribe of Terebinthaceze. The plants inhabit chiefly the tropical parts of America, Africa, and India ; some, however, are found in Europe. The order is unknown in Australia. There are 46 known genera and 450 species. Examples —Anacardium, Rhus, Mangifera, Spondias. The order is characterised by the presence of an acrid resinous juice. In some cases, however, the fruit of the plants is edible. Many of them supply varnishes. Anacardiwm occidentale furnishes the Cashew-nut, which is remarkable for its large succulent peduncle sup- porting the fruit or nut (fig. 248, p.173). The pericarp has the acrid properties which pervade the order, while the seed is eatable. A vesi- cating oil is procured from the pericarp, and is called cardole in the East Indies. The fleshy peduncle is acid and edible, and a bland gum exudes from the bark. Pistacéa vera is the Pistacia or Pistachio nut- tree, which extends from Syria to Bokhara and Caubul, and is culti- vated in the south of Europe. It has green-coloured oily kernels, 474 ANACARDIACEA. which are used as articles of diet. The Hebrew word p'3012 (botnim), translated nuts in Gen. xliii. 11, is supposed to refer to the fruit of this plant. P. Terebinthus is a native of the southern part of Europe, and the northern part of Africa, and yields a liquid resinous exudation, known as the Chian or Cyprian turpentine. The turpentine receives its name on account of being collected in the island of Chio or Scio, where the plant thrives. The plant is common on the islands and shores of the Mediterranean, and is found in Asia Minor, Syria, and Palestine. The tree attains a height of 30 or 35 feet, and one tree will yield ten ounces of the liquid resinous matter, which thickens on exposure to air, by the loss of volatile oil. Like other turpentines, it has diuretic and excitant properties. Pistacia Lentiscus, the Len- tisk, a native of the coasts and islands of the Mediterranean, furnishes the concrete resinous exudation called Mastich or Mastic. It isa bush of about 10 or 12 feet in height, which is cultivated abundantly in the island of Chios. Mastich is used as a masticatory for consoli- dating the gums and cleansing the teeth. It has also been employed as an antispasmodic, and it enters into the composition of varnishes. Rhus Toxicodendron, Poison-oak, is a shrub found in Canada and the United States, the leaves of which have been used as stimulants in cases of palsy. Like the other species of this genus, it yields an acrid milky juice, which becomes black on exposure to the air. Rhus radicans, Poison-ivy, or Poison-vine, is probably another name of the same species, Rhus venenata, Poison-sumach, or Poison-elder, has acrid, poisonous properties, and contact with it, in some instances, gives rise to inflammation of the skin. Cases are related of persons who are peculiarly liable to be thus affected, and in whom the irrita- tion caused by the juice of the poisonous species of Rhus is very great, and even alarming. Rhus coriaria, R. typhina, and R, glabra, are used for tanning, and their fruit is acid. Rhus Cotinus is called Arbre d perruque (Wig-tree) in France, on account of the hairy appearance of its abortive pedicels. Many of the plants in this order furnish var- nishes and marking ink. Semecarpus Anacardium, commonly called the Marking-nut tree, supplies the Sylhet varnish, while Melanorrhea usitatissima furnishes that of Martaban. Stagmaria vernicifiua is the source of the hard black varnish called Japan Lacquer. The leaves of many of the species of Schinus, as S. Molle, when torn and thrown on the surface of water, send out a resinous matter with great force, so as to cause a sort of spontaneous motion by the recoil. Although a resinous principle pervades the plants of this order, yet in some cases it is not developed in the fruit, which becomes eatable. Of this an illustration is furnished by the Mango, the produce of Mangifera indica. The Hog-plums of the West Indies are furnished by various species of Spondias, as 8. purpurea and Mombin. Spondias dulcis yields the fruit called Wi in the Fiji islands. BURSERACEA. 475 Order 62.—Bursreracrs,’ the Myrrh and Frankincense Family. (Polypet. Perigyn.) Flowers usually bisexual, sometimes unisexual by abortion. Calyx persistent, regular or nearly so, with 2 to 5 divisions. Petals 3-5, inserted at the base of the calyx; estivation valvate or imbricated. Stamens twice or four times as many as the petals, peri- gynous. Disk covering the base of the calyx often in a ring-like man- ner. Ovary superior, sessile, 1-5 celled; ovules in pairs, anatropal, . pendulous or suspended ; style 1 or none; stigma simple or lobed, sometimes capitate. Fruit dry, 1-5-celled, indehiscent, or its epicarp splitting into valves. Seeds solitary, exalbuminous, with a superior radicle next the hilum, and cotyledons, which are fleshy or wrinkled, — Trees or shrubs, abounding in resin, with opposite or alternate compound leaves, which are frequently stipulate and dotted. They are natives of tropical regions. There are two tribes :—1. Burserez, with a 2-5-celled ovary ; 2. Amyridex, with an unilocular ovary. Some look upon the stamens of Amyrides as truly hypogynous, and consider the order as allied to Aurantiacee, Authors give 26 genera and 56 species. Examples—Amyris, Boswellia, Bursera, Balsamodendron, The plants yield a fragrant balsamic and resinous juice, which, in a dry state, is often used as frankincense, and is employed medi- cinally as a stimulant or expectorant. The resin called Elemi is supposed to be produced by species of Canarium (C. commune and balsamiferum, The resin contains a stimulant volatile oil. Olibanum (Frankincense), the mab (Lebonah) of the Scriptures, is procured from the stem of several species of Boswellia which inhabit the hot and arid regions of eastern Africa near Cape Gardafui, and of the southern coast of Arabia. Among these may be mentioned Boswellia Carterit of Birdwood, including several varieties, B. Bhau-Dajiana of Birdwood, and B. Frereana. The two latter are natives of the Somali country. The last mentioned yields a resin called Luban Matti, which Hanbury considers to be the substance originally known as Elemi. The quan- tity of olibanum exported from Bombay in 1872-73 was 25,100 cwt. It is used for incense in the Roman Catholic and Greek churches. Bos- wellia thurifera, the Salai tree of India, produces an odoriferous resin. It contains a volatile oil, and has been used as a stimulant, and as a material for fumigation. Balsamodendron (Protium ?) Myrrha, a shrub growing in Abyssinia, appears to be the source of the officinal myrrh, the 719 (mor) of the Bible. It is a bitter aromatic gum-resin, con- taining volatile oil, and was used in ancient times as frankincense. It is a heating stimulant, and is employed medicinally as an emmenagogue and diaphoretic, as well as for arresting various mucous discharges, The resin called Bdellium is procured from various species of Balsamo- dendron, as B. africanum and Roxburghti. The bdellium of Scripture (nda) is not known. Thecelebrated balsam called Balm of Gilead, ¥ (tzori) is an exudation from Balsamodendron gileadense, Tacamahac A476 CONNARACEAI—LEGUMINOSAL is procured from Elaphriwm tomentosum. Various other balsams and resins are ‘yielded by plants of this order. Amyris tovifera is said to be poisonous. Order 63.—ConnaRacea, the Connarus Family. (Polypet. Perigyn.) Flowers bisexual, rarely unisexual. Calyx 5-partite, regu- lar, persistent ; sestivation imbricate or valvate. Petals 5, inserted at the base of the calyx. Stamens twice as many as the petals, inserted with them, and doubtfully hypogynous; filaments united at the base. Ovary consisting of one or more separate carpels, each having a ter- minal style and a dilated stigma; ovules in pairs, collateral, ascend- ing, orthotropal. Fruit follicular, dehiscing along the ventral suture. Seeds solitary or in pairs, erect, with or without albumen, sometimes arillate ; embryo with a superior radicle, remote from the hilum, and cotyledons, which are either fleshy or leafy—Trees or shrubs, with compound, alternate, exstipulate leaves, which are not dotted. They are tropical plants, and according to Endlicher are common in America. Some of them have febrifugal properties. Omphalobiwm (Agelea) Lam- berti is said to furnish Zebra-wood. This order, as well as the orders Anacardiacee and Amyridacez, are by many considered truly hypo-, gynous, and as belonging to Thalamiflore. Lindley includes them in his Rutal alliance. Genera 12, species 140. Hxamples—Connarus, Omphalobium, Cnestis. Order 64.— Lecuminos& (Fabacee of Lindley), the Pea and Bean Tribe. (Polypet. Perigyn.) Calyx 5-partite, toothed, or cleft (figs. 700, 701 ¢ c), with the odd segment anterior ; segments often unequal and variously combined. Petals 5 (figs. 700, 701), or by abortion, 4, 3, 2, 1, or 0, inserted into the base of the calyx, some- times equal, but usually unequal, often papilionaceous, with the odd petal superior (fig. 701 ¢). Stamens definite or indefinite, usually perigynous, distinct, or monadelphous or diadelphous (fig. 701, ¢) or rarely triadelphous ; anthers bilocular, versatile. Ovary superior, 1-celled, consisting usually of a solitary carpel (fig. 701 0), sometimes of 2-5; ovules 1 or many; style simple, proceeding from the upper or ventral suture; stigma simple (fig. 701 s). Fruit a legume (figs. 536, p.301 ; 565, p. 313 ; 702), or a drupe. Seeds solitary or several (fig. 702), sometimes arillate, often curved (fig. 703); embryo usually exalbuminous, straight, or with the radicle bent upon the edges of the cotyledons (figs. 465, p. 258; 612, p. 340), which are either epi- geal or hypogeal (p. 536) in germination (fig. 704), and leafy (Phyllo- lobes), or fleshy (Sarcolobece).—Herbaceous plants, shrubs, or trees, with alternate usually compound leaves, having two stipules at the base of the petiole (fig. 209, p. 98), and two at the base of each leaflet in the pinnate leaves. Pedicels usually articulated. The flowers are fre- quently papilionaceous (fig. 316, p. 205), and the fruit is commonly leguminous (figs. 556, p. 307; 565, 566, 567, p. 313), and by the LEGUMINOSA. 477 presence of one or other of these characters the order may be recog- nised. It is remarkable that one or other of these distinctions dis- appears in a great number of cases. Czesalpiniee have irregular flowers, with spreading petals and stamens adhering to the calyx; © WW) Fig. 701. Fig. 702. Fig. 704. others have no petals at all, or some number less than five; while Mimosez have perfectly regular flowers and indefinite hypogynous stamens. Detarium and other plants of this family bear fruits not to be distinguished from a drupe. Leguminous plants and Roseworts have so many features in common that it may be affirmed that no positive character has been discovered to distinguish the one order from the other, except the inferior position of the odd calycine lobe. Figs. 700-704. Organs of fructification of Lathyrus odoratus, Sweat-pea, a papilionaceous flower, showing the structure of the natural order Leguminose. Fig. 700. Diagram of the flower, showing five divisions of the calyx, 5 petals, consisting of 2 parts forming the carina, 2 alee, and the vexillum, which is superior, 10 stamens in 2 rows, diadelphous ; ovary 1- celled, formed by a single carpel; one of the ovules shown with its funiculus attached to the ventral suture. Fig. 701. Longitudinal section of the flower of Lathyrus odoratus. ec, Calyx, with five segments. ¢, Vexillum or standard, being the superior or posterior odd petal. a, One of the ale, or wings. ca, One-half of the carina, or keel. t¢, Tube of the stamens, the filaments being united in two bundles, or diadelphous. 0, Ovary laid open, showing the ovules attached to the placenta, on the ventral or upper suture. s, Stigma, at the apex of the style, which is continuous with the ventral suture. Fig. 702. Fruit, a Legume or Pod, opening by two valves, and dehiscing by the ventral and dorsal suture. Seeds attached on each side of the ventral suture, curved upon themselves, having a marked hilum and funiculus (podosperm or umbilical cord). Fig. 703. A Seed separated. J, Funiculus. c, Hilum, which is united to the funiculus. m, Micropyleorforamen. Fig. 704. Embryo, which occupies the entire seed after the spermoderm is removed. ¢¢, Two cotyledons separated: they are fleshy and hypogeal—t.e. remain under ground during germination. g, Gemmule or plumule, 7, Radicle. 478 LEGUMINOSA. The plants of the order are very generally distributed over the globe, but many genera are very limited in their range. De Candolle gives the following geographical distribution of the 3600 species known in his day :— Equinoctial America ‘ , . ¢ : & - 605 Basin of the Mediterranean. é i ‘ F . 468 East Indies . é i a , a . 452 Cape of Good Hope a 3 3 ‘ . : . 358 Levant . a i é i , ¢ ‘ . 250 New Holland . é i i x i 3 ‘ » 220 West Indies . ‘ ‘ : . 221 Europe, excepting the Mediterranean . z ‘a » 184 United States 5 ¥ : ‘ 7 7 . 188 Mexico . 3 ¥ ; ‘ 2 ‘ » 152 Equinoctial Africa | ‘ ‘ ‘ . ; : - 180 Siberia . * F é ‘ ‘ : 2 e “120 Arabia and Egypt < < : ‘ 3 : ‘ 87 China, Japan, Cochin- China . é ‘ ‘ : : 77 Isles of Southern Africa . j Fi , 3 é 5 42 South America, Pay the moe ‘ e : . : 29 Canaries é z ‘ - P 7 « 'S1 South Sea Islands . . ‘ 13 No native species occur in the island of Tristan d’Acunha, nor in the cold Antarctic islands. The order has been divided into three sub-orders :—1. Papilion- aces ; papilionaceous flowers, petals imbricated in estivation, and upper one exterior, This sub-order is subdivided into the tribes Podalyriex, Lote, Vicies, Hedysareze, Phaseoleze, Dalbergiez, Sophoreze ; according to the nature of the filaments, whether free or variously united, the form and dehiscence of the legume, the cotyle- dons whether fleshy or leafy, and the simple or compound nature of the leaves. Examples—Podalyria, Lotus, Cytisus, Pisum, Hedysarum, Phaseolus, Dalbergia. 2. Ceesalpinieze ; flowers irregular, sub-papilion- aceous, petals spreading, imbricated in estivation, upper one interior, stamens often free. Examples—Hematoxylon, Cesalpinia, Cassia, Swartzia, Amherstia, Bauhinia, Copaifera, and Ceratonia. 3. Mimosez ; flowers regular, petals valvate in estivation, stamens free or mona- delphous. Ezamples—Parkia, Mimosa, Acacia. Sub-orders. Tribes. Species. British species. (1. Podalyriee . : 350 ba 0 2. Lotee with 3 8000 .. 48 Viciez. ... 7 ve 28 1. Papilionacer . .4 3. Hedysaree . : 500 oe 4 4. Phaseolee . ; 650 0 5. Dalbergiee . ‘i 250. 0 (6. Sophoree . . : 50 0 2. Cesalpiniee . 5 ; é ‘ . 700 0 3. Mimosez 6 ‘ ji 7 : 1000 0 6500 75 LEGUMINOSA. 479 The preceding is the estimate of species in the different sub-orders and tribes, considered in reference to the flora of the globe and the flora of Britain (Bentham and Henslow). The number of known genera at the present day is about 400, including about 6500 species. This is a very extensive and a very important natural order. It embraces many valuable medicinal plants, such as those yielding Senna, Gum-arabic, Tragacanth, Catechu, and Kino; important dyes, as Indigo and Logwood ; many valuable timber-trees, as Locust- tree and Rosewood ; plants furnishing nutritious food, such as the Bean and Pea, Haricots, Kidney-beans, Lentils, Pigeon-peas, Chick- pea. The properties of the order may be considered in general as wholesome, although it contains some poisonous plants. Lindley, however, says that the order must be considered upon the whole as poisonous, and that the plants used for food are exceptions to the general rule; the injurious juices of the order not being in such instances sufficiently concentrated to prove injurious, being replaced to a considerable extent by either sugar or starch. Sub-order Papilionacew, The plants in this section have frequently beautiful showy flowers; for example, Robinia, Laburnum, Wistaria, Lupinus, Clianthus, Erythrina (Coral-flower), Hovea, They are often nutritious. The various kinds of Clover, Beans, Peas, and Pulse belong to it. The common red Clover is Trifolium pratense. White or Dutch Clover (T. repens) springs up frequently on ground recently cleared. The Shamrock is generally considered as a species of Trefoil. Various species of Medick and Lucerne (Medicago, fig. 567, p. 313), of Saintfoin (Onobrychis), and Melilot (Melilotus), are cultivated as food for cattle. Several species of Medicago are called Calvary Plants, on account of dark, blood-like spots on their leaflets. Medicago Echinus is one of the symbolic plants of the East. Many are used for their medicinal qualities. Glycyrrhiza glabra. (Liquiritia officinalis) is the plant which yields liquorice-root, This plant is a native of the southern part of Europe, and it has been occasionally cultivated with success in Britain, especially at Pontefract in Yorkshire, and at Mitcham in Surrey. An extract is prepared from the root or under- ground stem by decoction in water, and subsequent inspissation. It owes its sweetness to a peculiar principle called Glycion, or Glycyr- thizin, which appears also to be present in the root and leaves of other papilionaceous plants, as Glycyrrhiza echinata and glandulifera, Tri- folium alpinum, and Abrus precatorius, Liquorice is used medicinally asa demulcent. A sweet secretion (a kind of Manna) is produced by Alhagi Maurorum (Camel’s-thorn). Astragalus verus, creticus, aristatus, gummifer, and other species, yield an exudation known by the name of Gum Tragacanth. A. verus seems to be the chief source of the European tragacanth. Itis a shrub found in Asia Minor and Persia, and the gum is procured by exudation or incision. Tragacanth forms, 480 LEGUMINOSA. with cold water, a bulky jelly, while it is soluble in boiling water. It contains both Arabin and Bassorin in its composition, and is used as a demulcent. Myrospermum (Myroxylon) Pereire yields the Balsam of Peru, while Myrospermum (Myroxylon) toluiferum is the source of the Balsam of Tolu. These balsams are procured chiefly by making incisions in the trees. They consist of resinous and oily matter, with cinnamic acid, and they are used as stimulant expectorants. Ptero- carpus Marsupium, a tree of the Indian forests, furnishes the concrete exudation called Kino. Butea frondosa, the Dhak tree of the East Indies, yields a similar product ; it has bright orange-red petals, and a black calyx. African Kino is procured from Pterocarpus erinaceus, Kino is used as a powerful astringent, and is administered in the form of powder and tincture. Broom-tops, procured from Cytisus (Sarotham- nus) Scoparius, are used as adiuretic. The hairs from the legumes of Mucuna pruriens in the West Indies, and of M. Prurita in the East, under the name of Cowhage, or Cowitch, have irritating properties, and, mixed with syrup, they are used in the treatment of intestinal worms. The leaves of Colutea arborescens, Bladder-Senna (fig. 566, p- 313), are purgative, and are used abroad to adulterate the obovate or blunt-pointed Senna. The leaves of Tephrosia apollinea are also purgative, and are occasionally mixed with Alexandrian Senna. The bark of Andira inermis, the Cabbage-tree of the West-Indies, acts as a purgative and anthelmintic. The fruit of Geoffroya superba, Umari, is much used by the inhabitants of Brazil on the banks of the Rio San Francisco ; the fruit is a drupe. Besides the plants which have active medicinal qualities, there are others which are valuable in commerce and the arts, as furnishing food, dyes, fibres, timber. Various species of Indigofera, as I. tinctoria and cerulea, furnish the Indigo of commerce. Piéerocarpus santalinus yields red Sandal-wood, which is used as adye. It is probably the pybs Almug or Algum-trees: of Scripture. P. Draco yields Gum- Dragon, and P. Dalbergioides is said to yield Andaman redwood, and to be valuable both as a dye and as timber. Baptisia tinctoria gives a blue dye, and is the wild Indigo of the United States. Dalbergia Sissoo is an Indian forest tree, which is valued on account of its wood. Crotalaria juncea supplies fibres, which are known as Sun or Bengal Hemp. The fragrant seeds of Dipterix odorata are known as Tonka- beans. A similar fragrance is given out by some species of Melilot, the flowers and seeds of which are employed to give the peculiar odour to Gruyere cheese. Arachis hypogewa produces its legumes under ground, and receives the name of underground Kidney-bean, or Ground-nut. Erythrina monosperma yields Gum lac. The roots of Glycine Apios, or Apios tuberosa, are used as an article of food in Ame- Tica, Robinia pseudo-acacia is often cultivated in Britain as the Locust- tree. The tree attains in England a height varying from forty-five to LEGUMINOSA, 481 eighty feet, and sometimes has a diameter of three feet. Its wood is durable. According to Bertoloni, a kind of Ebony is the produce of Fornasinia ebenifera, a papilionaceous plant, found in Caffraria, near Mozambique. Rosewood is said to be the timber of two or three species of Triptolomea. It is rare to find papilionaceous plants pro- ducing double flowers. The Whin is one of the plants which exhibits this monstrosity. Desmodium or Hedysarum gyrans (the Gorachand of Bengal) exhibits a remarkable irritability in its leaves (p. 378). There are certain poisonous plants in this sub-order. The seeds and bark of Cytisus Laburnum are narcotic; such is said also to be the case with those of Lathyrus Cicera and L. Aphaca, The roots of many species of Phaseolus, as P. multiflorus, the Scarlet-runner, and P. radi- atus, are poisonous. The branches and leaves of Tephrosia toxicaria, and the bark of the root of Piscidia erythrina, Jamaica Dogwood, are employed as fish poisons. Physostigma venenosum yields the Calabar ordeal-bean (see figure Trans, R. Soc. Ed., vol. xxii.) It causes con- traction of the pupil. The plant has a remarkable hooded stigma (fig. 445; "p. 250). Gompholobiwm wneinatum has poisoned sheep in the Swan River colony. Coronitila varia acts as a narcotic poison. The leaves of it and of Coronilla Emerus are sometimes used to adul- terate Senna. Sub-order Cesalpiniee. In this section there are many plants which furnish purgative remedies. Among these may be noticed vari- ous species of Cassia, ©. lanceolata, acutifolia, elongata, obtusata, and obovata, supply the various kinds of Senna known as Alexandrian or Egyptian, Tripoli, and East Indian Senna. Other species also, as Cassia marilandica, Absus, corymbosa, biflora, tomentosa, alata, and Por- turegalis, have purgative leaves, Cassia Fistula, called also Catharto- carpus Fistula, has an indehiscent pod, divided by numerous transverse phragmata (fig. 429, p. 244), and containing a laxative pulp, which is a secretion from the endocarp. A pulp having similar properties is procured from the pericarp of Tamarindus indica, the Tamarind-tree. The pod of Ceratonia Silique is known as the Algaroba-bean, and is used occasionally for feeding horses. The tree is denominated Carob- tree, and sometimes Locust-tree, or St. John’s Bread, from an errone- ous idea that the pods supplied food to John the Baptist in the wilder- ness. The pods of Hymencea Oourbaril, the West Indian Locust-tree, supply a nutritious matter; its inner bark is anthelmintic, and the plant yields a kind of resin called Animé. The bark of Guilandina Bonducella, the Nicker-tree, is bitter, tonic, and its seeds are said to be emetic. The curved pods of Cawsalpinia coriaria, under the name of Divi-divi, are used for tanning. Ocsalpinia brasiliensis yields the Brazil-wood of commerce ; and the Mora-wood of Guiana is yielded by a large tree called Mora eacelsa, Many dyes are furnished by the plants of this sub-order. Haematoxylon campechianum gives Logwood 21 482 LEGUMINOSA—MORINGACEA. or Campeachy-wood, which is employed both as a dye and as an astringent. The inner wood is the part employed both in the arts and officinally, The alburnum is of a yellowish colour, and is not imported. The red colouring principle is Hematoxylin. Cesalpinia echinata furnishes Pernambuco-wood ; C. Sappan, Sappan-wood, the Wukkum or Bukkum-wood of Scinde; Baphia nitida, Camwood. Various species of Copaifera, as C. Jacquinii, Langsdorfin, bijuga, multijuga, Martti, guianensis, coriacea, etc., furnish the balsam of Copaiva, of which two kinds are distinguished—the West Indian and Brazilian. The balsam contains a resin and volatile oil. It is used in medicine as a stimulant, cathartic, and diuretic, and is especially employed in the treatment of mucous inflammations. Cassia Chame- crista, marilandica, and nictitans, all exhibit, according to Bromfield, a high degree of irritability ; the leaflets close together when gathered, and when rudely handled, or brushed by the feet in walking through the herbage. Trachylobiwm mossambicense yields Zanzibar copal. Sub-order Mimosee, The plants of this section yield Gum in quantity, and their bark is frequently astringent. Acacia Ehrenbergit, tortilis, Seyal, arabica, vera, gummifera, Adansonti, Verek, albida, and various other species, yield the gummy substances known as Gum Arabic, Gum Senegal, Barbary Gum, and East Indian Gum. A kind of gum is procured at the Cape of Good Hope from Acacia Karroo ; and in Australia, A. decurrens yields another variety. A variety of Indian gum procured from A. arabica is called Babul, or Babool- Gum ; Babul-bark is used for tanning in Scinde. These gums are all more or less nutritive and demulcent, and are administered in the form of mucilage, emulsion, or lozenges. The Wattles of Australia are species of Acacia, which furnish astringent barks, An extract made from them has been imported for the purpose of tanning. The duramen of Acacia Catechu, an Indian shrub, furnishes a kind of Catechu, or Cutch, which contains much tannin, and is used for tanning, and as a power- ful astringent. Some of the New Holland Acacias are remarkable for the peculiar development of the petiole, which assumes the form of a phyllodium (fig. 204, p. 96). The large seeds of Entada scan- dens are sometimes carried by the winds and tides from the West Indies to the shores of the outer Hebrides. Acacia Seyal is supposed to be the Shittah Tree, nuw, of Scripture, which furnished Shittim wood. A. formosa supplies the Cuba timber called Sabicu. Some of the plants in this sub-order display peculiar irritability in their pinnate leaves. This is particularly the case with Mimosa sensitiva and pudica, which are commonly called sensitive plants (p. 376). Almost all of the pinnate-leaved Leguminous plants close their leaves in a marked way during darkness, Order 65.—Morincacza, the Moringa Family. (Polypet. Pe- rigyn.) Calyx 5-partite ; estivation slightly imbricated. Petals 5, MORINGACEZ—ROSACEA. 483 rather unequal, upper one ascending. Stamens 8 or 10, perigynous ; filaments slightly petaloid, callous, and hairy at the base; anthers simple, 1-celled, with a thick convex connective. Disk lining the tube of the calyx. Ovary superior, stipitate, 1-celled ; ovules anatro- pal, attached to parietal placentas; style filiform; stigma simple. Fruit a pod-like capsule, 1-celled, 3-valved, opening by loculicidal dehiscence. Seeds numerous, half buried in the spongy substance of the valves, sometimes winged, exalbuminous ; embryo with a supe- rior, straight, small radicle, and fleshy cotyledons.—Trees, with bi- or tri-pinnate, stipulate leaves, natives of the East Indies and Arabia. Some of them are pungent and aromatic. The seeds of Moringa pterygosperma, Horse-radish tree, are winged, and are called Ben-nuts. From them is procured a fiuid oil, used by watchmakers, and called Ben Oil. The root is pungent and stimulant, and resembles Horse- radish in its taste. It is used as a stimulant in paralytic affections and intermittent fever. It is also a rubefacient. Some place this order near Violacez, others near Capparidacee. Genus, 1; species, 3. Example—Moringa. Order 66.—Rosacew, the Rose Family. (Polypet. Perigyn.) (Figs. 247, p. 172; 256, 257, p. 177; 300, p. 198; 313, p. 204; 419, p. 240; 705). Calyx 4-5-lobed (fig. 706 cc), the fifth lobe superior. Petals as many as the divisions of the calyx, often 5 (fig. 706 pe), sometimes wanting, perigynous, generally regular ; zstiva- tion quincuncial (fig. 705). Stamens inserted with the petals (fig. 706 ¢), definite or indefinite ; filaments incurved in eestivation : anthers bilocular (fig. 707), dehiscing longitudinally (fig. 354, p. 221). Ova- ries superior, either solitary or several, unilocular (fig. 708), sometimes uniting so as to form a many-celled pistil ; ovules, 1, 2, or more, ana- tropal, suspended (figs. 407 g, p. 236; 708 g), rarely erect; styles lateral (figs. 434, p. 246; 708, 710); stigmas usually simple. Fruit either achenia (fig. 294, p. 196), or drupes (figs. 407, p. 236 ; 709), or follicles or pomes (fig. 568, p. 314). Seeds erect or inverted, usually exalbuminous ; embryo straight, with the radicle next the hilum (figs. 710, 712), and leafy or fleshy cotyledons (figs. 597, p. 334 ; 711). —Herbaceous plants, or shrubs, or trees, with simple or compound, alternate, stipulate leaves (fig. 207, p. 98), and the flowers sometimes unisexual, They are found chiefly in the cold and temperate climates of the northern hemisphere. Some: are found on high mountains within the tropics, and a few occur in warm regions. The superior odd lobe of the calyx distinguishes this order from Leguminose. The order has been divided into the following sub-orders:—1. Chry- sobalanez, petals and stamens more or less irregular ; ovary stipitate, its stalk adhering on one side to the calyx, style basilar (fig. 435, p. 246), fruit a 1-2-celled drupe. 2. Amygdalez or Prunez (Drupa- cee of Lindley), tube of calyx lined with a disk, styles terminal, fruit 484 ROSACEA. a drupe (figs. 339, p. 213; 405, p. 235; 406-7, p. 236). 3. Spi reeew (fig. 102, p. 41), calyx-tube herbaceous, lined with a disk, fruit consisting of numerous follicles, seeds apterous. 4, Quillaiez, flowers unisexual, calyx-tube herbaceous, fruit capsular, seeds winged at the apex. 5. Sanguisorbe, or Poteriew, petals 0, tube of calyx thick- ened and indurated, lined with a disk, stamens definite ; nut solitary, enclosed in the calycine tube. 6. Potentille (including Rubez) (fig. 300, p. 198), calyx-tube herbaceous, lined with a disk which some- Fig. 709. \ Fig. 712. times becomes fleshy, fruit consisting of numerous achenia. 7. Rosez, calyx-tube contracted at the mouth, becoming fleshy, lined with a disk, and covering numerous hairy acheenia (figs. 294, p. 196 ; 313, p. 204). 8. Neuradew, calyx-lobes, with or without bracts, petals 5, carpels 5 or 10, uniovulate, fruit 5-10 valved. 9. Pomez (Pomaces of Lind- ley), tube of calyx more or less globose, lined with a fleshy and juicy Figs. 705-712. Organs of fructification of Rubus strigosus, illustrating the natural order Rosacee. Fig. 705. Diagram of the flower, with five divisions of the calyx, 5 quincun- cial petals, indefinite perigynous stamens, and numerous succulent carpels. Fig. 706. The flower cut vertically. ec, Calyx. pe, Petals. e, Stamens. d, Disk, lining the base of the calyx, upon which the stamens are inserted. i, Pistil, composed of several carpels. Fig. 707. Bilocular anther separated, with the upper part of the filament seen on the out- side. Fig. 708. Ovary, 0, cut vertically. g, Exalbuminous, suspended seed. s, Lateral style. Fig. 709. Fruit. jf, Fleshy carpels accompanied with the persistent calyx, ec, con- nected with which the withered filaments are seen. Fig. 710, Vertical section of a carpel, s, Lateral style. m, Fleshy mesocarp or sarcocarp. e, Endocarp. g, Seed. Fig, 711. Horizontal section of the exalbuminous seed. ¢, Integument (spermoderm). c, Cotyledons of the embryo. Fig. 712. Embryo isolated. It fills the entire seed. ROSACEA. 485 disk, fruit a 1-5-celled (fig. 568, p. 314) or spuriously 10-celled pomum. There are 71 known genera, and about 1000 species. Hxamples— Chrysobalanus, Amygdalus, Prunus, Spirea, Quillaia, Sanguisorba, Poterium, Potentilla, Rubus, Fragaria, Rosa, Neurada, Pyrus. Many of the plants of the order yield edible fruits, such as Raspberries, Strawberries, Brambles, Plums, Apples, Pears, Quinces, Cherries, Almonds, Peaches, Nectarines, and Apricots. Some are astringent, others yield hydrocyanic acid. Those belonging to the sub-order Chrysobalanee are principally natives of the tropical parts of Africa and America. Many of them furnish edible fruits. The drupes of Chrysobalanus Icaco are eaten in the West Indies under the name of cocoa-plums. The root and bark are used as astringents. The plants in the tribe Amygdalew are chiefly remarkable on account of the presence of hydrocyanic acid in their kernels, leaves, or flowers. Amygdalus communis, the Almond-tree, grows naturally in Barbary and in Asia, from Syria to Affghanistan. It is extensively cultivated in the south of Europe. It is the 1pw, Shaked, of the Old Testament. There are two varieties of the tree,—a. dulcis, yielding the sweet Almond, and @. amara, yielding the bitter Almond, In the former the style is much longer than the stamens, and there are glands on the base of the leaf; while in the latter the style is equal in length to the stamens, and the glands are situated on the petioles. The chief kinds of sweet Almonds are the Valentia, the Italian, and the Jordan, Almonds ; the latter come from Malaga. Under the name of shell Almonds, they are often sold with the brittle endocarps on them. They consist chemically of a bland fixed oil, and a kind of vegetable albumen called Emulsin or Synaptase. Bitter Almonds are imported from Mogadore. Besides a fixed oil and synaptase, they contain a bitter azotised principle called Amygdalin, which, when brought into contact with a solution of Emulsin, produces a volatile oil containing hydrocyanic acid. This gives rise to the peculiar aroma of bitter Almonds when mixed with water. Sweet Almonds are used medi- cinally, in the form of Emulsion, as demulcents. The hydrocyanated essential oil of bitter Almonds is sedative, and has been used as a substitute for Prussic acid. They sometimes produce derangement of the digestive functions, and give rise to nettle-rash. The leaves of Amygdalus persica (Persica vulgaris of some), the Peach, contain a similar oil, and have been employed as sedative and vermifuge. The flowers of the Peach exhale the odour of bitter Almonds. Peaches are divided into Freestone and Clingstone, according as the pulp (sarco- carp) separates easily from the endocarp or adheres to it. The fruit of Prunus domestica, the Plum-tree and its varieties, when dried, con- stitute Prunes, which are used medicinally, on account of their nutri- tive and laxative qualities. Some think that the Bullace, Damson, Orleans Plum, and the Quetches, are all derived from the common 486 ROSACES. Sloe. They differ much, however, in the form of the stone. The leaves of Prunus or Cerasus Laurocerasus, Cherry Laurel, or Common Bay Laurel, have been used medicinally, as anodyne and hypnotic remedies. The water distilled from them has poisonous properties, owing to the presence of a hydrocyanated oil, which seems to be de- veloped in a similar manner as in the case of bitter Almonds. The oil exists in large quantity in the young leaves. Prunus Lusitanica is the Portugal Laurel, which is extensively cultivated in Britain as an evergreen. The leaves of Prunus spinosa, the Sloe, have been used as a substitute for as well as an adulteration of Tea. The fruit of a variety of Cerasus avium, the Cherry, is used in the manufacture of Kirschenwasser. The kernel of Cerasus occidentalis is used for flavour- ing Noyau. The. flavour of Ratafia, Cherry-brandy, and Maraschino, is due to the kernels of Cerasus, The tribe Pome (fig. 257, p. 177) supplies many edible fruits, as Apples, Pears, Medlars (fig. 568, p. 314), and Quinces. The seeds, and occasionally the flowers and bark of some, yield hydrocyanic acid. All the cultivated varieties of Apple are derived by grafting from the native species, Pyrus Malus ; while Pears have their origin in Pyrus communis. The seeds or pips of Cydonia vulgaris (Pyrus Cydonia), the Quince, when boiled in water, yield a mucilaginous decoction, which has been used as a demulcent. Malic acid is found in some of the fruits of this sub-order. Eriobotrya japonica yields the Loquat, a Japan fruit. The other tribes contain plants which are distinguished by astrin- gent and tonic qualities. Gewm urbanum and rivale (Avens) have been employed as tonics and astringents, as also the root of Potentilla Tor- mentilla (Tormentil). Brayera anthelmintica (Hagenia abyssinica), Cusso or Kousso, an Abyssinian tree growing to a height of 60 feet, has been used as a vermifuge in cases of Tenia. The varieties of Scotch Roses are derived from Rosa spinosissima. The fruit (hips) of Rosa canina, the Dog-rose, which consists of the enlarged calyx and disk enclosing numerous acheenia (fig. 294, p. 196), is beat into a pulp with sugar, after the hairy achenes have been removed, and used as an acidulous refrigerant and astringent. The petals of Rosa gallica, Red, French, and Provins Rose, are employed in the form of infusion, as a tonic and slightly astringent remedy. The petals of Rosa centi- folia, the Hundred-leaved or Cabbage-rose (fig. 93, -p. 35), and its varieties, R. damascena, Damask-rose, R. moschata, Musk-rose, etc., are employed in the preparation of Rose-water, and of the oil or attar of Roses. It is stated by Sir R. Christison that 100,000 roses, the pro- duce of 10,000 bushes of Rosa damascena, yield at Ghazeepore, near Benares, only 180 grains of attar. The finest Rose perfume is said to be prepared at Grasse, in France. Oil of Roses is adulterated with sandal-wood oil, The bark of many species of Quwillaia, as Q. sapon- aria, is used as a substitute for soap. CALYCANTHACEAI—LYTHRACEZ. 487 Order 67—CatycantHacea, the Calycanthus Family. (Polypet, Perigyn.) Sepals and petals confounded, indefinite, combined in a fleshy receptacle ; wstivation imbricated. Stamens oo, perigynous ; anthers adnate, extrorse, with longitudinal dehiscence. Ovaries several, l-celled, adhering to the tube of the calyx ; ovules solitary or two, one above the other, anatropal ; style terminal. Fruit consisting of achzenia enclosed in the fleshy receptacle. Seed exalbuminous ; embryo straight ; cotyledons convolute ; radicle inferior.—Shrubs, with square stems, consisting of a central woody mass, with four smaller ones around (p. 61); leaves opposite, simple, scabrous, exstipulate. By many authors this order is placed between Dilleniacee and Mag- noliacese. The plants are natives of North America and Japan. Their flowers are aromatic; the bark of some is used as a carminative. Calycanthus floridus is called Carolina or common American Allspice. The order includes 2 genera and 3 species. Examples—Calycanthus, Chimonanthus. Order 68.—Lyturacea, the Loosestrife Family. (Polypet. Perigyn.) Calyx tubular, lobed, the lobes sometimes with intermediate lobes or teeth ; eestivation valvate. Petals alternate with the primary lobes of the calyx, very deciduous, sometimes 0. Stamens inserted into the tube of the calyx a little below the petals, equal in number to them, or two, three, or four times as many ; anthers adnate, dithecal, introrse, with longitudinal dehiscence. Ovary superior, 2-6-celled ; ovules numerous, anatropal; style filiform ; stigma usually capitate. Fruit a dehiscent membranous capsule, surrounded by the calyx, but not adherent to it, sometimes l-celled by the obliteration of the dis- sepiments. Seeds numerous, small, apterous, or winged, exalbuminous, attached to a central placenta ; embryo straight ; cotyledons flat and foliaceous ; radicle next the hilum.—Herbs and shrubs, with branches which are usually tetragonal, and with opposite, rarely alternate, entire, exstipulate leaves without glands. They are natives of Europe, North and South America, and India. Authors give 30 genera, including about 250 species. Examples—Lythrum, Cuphea, Lagerstrémia. Many of the plants of the order are distinguished by astringent properties, and some are used for dyeing. Lythrum Salicaria, Purple Loosestrife, or Willowstrife, a European plant, found also in Australia, has been used in cases of diarrhoea, on account of the tannin in its composition. Its flowers are trimorphic (p. 285). The flowers of Grislea tomentosa are employed in India, mixed with Morinda, for dye- ing, under the name of Dhaee. Heimia salicifolia is said to possess diaphoretic properties, and is considered by the Mexicans as a potent remedy for venereal diseases, The Henna, or Alhenna of the Arabs, which is used in Egypt for dyeing orange, is the product of Lawsonia inermis. The Cupheas are remarkable for the mode in which the pla- 488 RHIZOPHORACEZ—VOCHYSIACEZ—COMBRETACEE, centa bursts through the ovary and floral envelopes, so as to expose the seeds. Order 69.—RuizopHorace®, the Mangrove Family. (Polypet. Epigyn.) Calyx adherent, 4-12-lobed ; eestivation valvate, or some- times calyptriform. Petals arising from the calyx, alternate with the lobes, and equal to them in number. Stamens inserted with the petals, twice or thrice their number; filaments distinct, subulate ; anthers erect. Ovary 2-3-4-celled; ovules 2 or more in each cell, anatropal. Fruit indehiscent, crowned by calyx, unilocular, monosperm- ous. Seed solitary, pendulous, exalbuminous; cotyledons flat; radicle long, piercing the fruit.—Trees or shrubs, with simple opposite leaves, and deciduous interpetiolary stipules. They are found on the muddy shores of the tropics. There are 17 genera and about 50 species known. Examples—Rhizophora, Kandelia, Cassipourea. The plants of the order have frequently an astringent bark, which is in some cases used for dyeing black. Rhizophora Mangle, the Man- grove, forms thickets at the muddy mouths of rivers in tropical coun- tries, and sends out adventitious roots, which often raise the main trunk much above its original level, and give the tree the appearance of being supported upon stalks (fig. 99, p. 39). The fruit is sweet and eatable. The embryo germinates before the fruit falls, and the radicle is much elongated before the seed drops into the mud. The anther consists of numerous cells containing pollen. Order 70.—VocuystacE#, the Vochysia Family. (Polypet. Pe- rigyn.) ~Sepals 4-5, united at the base, unequal, the upper one largest and spurred ; estivation imbricated. Petals 1, 2, 3, or 5, alternate with the divisions of the calyx, and inserted into its base, unequal. Stamens 1-5, opposite to or alternate with the petals, perigynous, one having an ovate, fertile, 4-celled anther, the rest being sterile. Ovary free, or partially so, 3-celled ; ovules solitary or in pairs, rarely nu- merous, amphitropal or anatropal; style and stigma one. Fruit a triquetrous, 3-celled and 3-valved capsule, usually with loculicidal de- hiscence. Seeds usually 1-2 in each cell, erect, exalbuminous, attached to a central placenta ; embryo straight ; cotyledons large and leafy ; radicle short and superior—Trees or shrubs, with opposite, entire, stipulate leaves. They inhabit the warmer parts of America. Their properties are little known. Their flowers are reputed to be very sweet, and some are said to have a resinous juice. The order is by some placed near Polygalace, There are 7 genera enumerated, in- cluding 100 species. Hxamples—Vochysia, Qualea. Order 71,—ComBretacem, the Myrobalan Family. (Polypet. Lipigyn.) Calyx 4-5-lobed, lobes deciduous. Petals arising from the orifice of the calyx, alternate with the lobes, or wanting. Stamens epigynous, twice as many as the lobes of the calyx, rarely equal in noumber, or thrice as many; filaments distinct, subulate ; anthers COMBRETACEA—-MELASTOMACEAi—PHILADELPHACEH, 489 _, dithecal, dehiscing longitudinally or by recurved valves. Ovary adherent to the tube of the calyx, unilocular ; ovules 2-4, pendulous ; style 1; stigma simple. Fruit succulent or nut-like, inferior, unilo- cular, indehiscent, often winged, Seed solitary, pendulous, exalbu- minous ; cotyledons leafy, usually convolute, sometimes plicate; radicle turned towards the hilum.—Trees or shrubs, with altefnate or opposite, exstipulate, entire leaves. They are natives of the tropical regions of Asia, Africa, and America. The general property of the order is astrin- gency. Many are used for tanning, and some for dyeing. The fruit of Terminalia Belerica, and of T. Chebula, under the name of Myro- balans, is used as an astringent. The seeds of Terminalia Catappa are eaten like almonds. The order has been divided into three tribes :— 1. Terminaliex, petals 0, cotyledons convolute. 2. Combretex, petals present, cotyledons plicate. 3. Gyrocarpex, petals 0, cotyledons con- volute, anthers, dehiscing by recurved valves. There are 15 genera, including 240 species. Hxamples—Terminalia, Combretum, Quisqualis, Gyrocarpus, 7 Order 72——MzLastomacem, the Melastoma Family. (Polypet. Perigyn. or Epigyn.) Calyx with 4, 5, or 6 divisions, which are more or less deep, or are sometimes united and separate from the tube like alid. Petals equal to the segments of the calyx, perigynous, zsti- vation twisted. Stamens equal in number to the petals and alternate with them, usually with intermediate sterile ones; filaments curved downwards in the young state ; anthers long, often beaked, bilocular, dehiscing by two terminal pores or longitudinally. Ovary more or less adherent to the calyx, mutilocular ; ovules usually 00; style 1; stigma simple, either capitate or minute. Fruit multilocular, either capsular, with loculicidal dehiscence, or succulent and indehiscent, with calyx attached. Seeds o , minute, attached to central placentas, exalbuminous ; embryo straight or curved; cotyledons sometimes unequal, flat, or convolute.—Trees, shrubs, or herbs, with opposite, undivided, usually entire, often 3-9-ribbed leaves, not dotted. They are found chiefly in warm climates. Many are natives of America and India. There are no unwholesome plants in the order, and the succulent fruit of several is edible. A slight degree of astringency pervades all the plants of the order, and hence some are used medi- cinally in cases of diarrhea, The name Melastoma (widas, black, and oréuwc, mouth) is derived from the circumstance that the fruit of some dyes the lips black. There are two sub-orders :—1. Melastomes, with ribbed leaves and flat cotyledons. 2. Memecylex, with ribless leaves and convolute cotyledons, Authors notice 134 genera, com- prising 1800 species. Examples—Melastoma, Osbeckia, Lasiandra, Rhexia, Lavoisiera, Miconia, Charianthus, Memecylon, Mouriria. Order 73,—PHILADELPHACEa, the Syringa Family. (Polypet. Epigyn.) Calyx with a 4-10-divided, persistent limb. Petals alter- \ 490 PHILADELPHACEAI—MYRTACEE, nate with the divisions of the calyx, and equal to them in number ; estivation convolute, imbricate. Stamens oo (rarely 10), in one or two rows, arising from the orifice of the calyx. Ovary adherent to the tube of the calyx; styles distinct, or united into one; stigmas 4-10; ovules co, attached to a central placenta. Fruit a 4-10-celled capsule, free above. Seeds oo , scobiform, subulate, smooth, pendulous, with a loose membranous arillus ; albumen fleshy ; embryo straight, about as long as the albumen ; cotyledons flat ; radicle next the hilum, obtuse.— Shrubs with deciduous, opposite, exstipulate leaves without dots ; flowers usually in trichotomous cymes. They are natives of the South of Europe, of North America, Japan, and India. They have no marked properties. The flowers of Philadelphus coronarius, Syringa or mock-orange, have a peculiar odour, which to some persons is overpowering and disagreeable. The smell is due to the presence of an oil. Deutzia scabra has a scurfy matter on its leaves,twhich, under the microscope, is seen to consist of beautiful stellate hairs. The leaves are in conséquence used in Japan by polishers. Its inner bark is.used for poultices. The order is included by some in the tribe Hydrangiez, of the natural order Saxifragacee, There are 5 genera enumerated, including 22 species. £xamples—Philadelphus, Deutzia, Decumaria. Order 74.—Myrracex, the Myrtle Family. (Polypet. Epigyn.) Calyx 4-5-6-8-cleft, the limb sometimes cohering at the apex, and falling off like a lid; estivation valvate. Petals attached to the calyx, alternating with its segments, and equal to them in number, with a quincuncial estivation, rarely 0. Stamens inserted with the petals, twice as many as the petals, or oo ; filaments distinct, or united in one or more parcels, curved inwards in the bud ; anthers ovate, dithecal, with longitudinal dehiscence. Ovary inferior, 1-6-celled ; style and stigma simple ; ovules anatropal, pendulous or erect. Fruit dry or fleshy, dehiscent or indehiscent, Seeds usually oo , attached to a central placenta ; mostly exalbuminous ; embryo straight or curved ; cotyledons distinct (fig. 610, p. 339), or consolidated with the radicle, which is next the hilum.—Trees or shrubs, with opposite, rarely alternate leaves, which are usually entire and dotted, and frequently have an intramarginal vein. They are natives chiefly of warm coun- tries, as South America and the East Indies. Many, however, are found in more temperate regions. Some of the genera are peculiar to Australia. The order has been divided into the following tribes :—1. Chamelauciex, heath-like plants, with a 1-celled ovary, indehiscent capsule, and opposite dotted leaves. 2. Leptospermex, having a mul- tilocular capsule with loculicidal dehiscence, and opposite or alternate, usually dotted leaves. 3. Myrtew, having a baccate fruit, distinct stamens, opposite dotted leaves. 4. Barringtonies, having a fleshy l-celled fruit, monadelphous stamens, albuminous seeds, opposite or MYRTACEA. 491 verticillate leaves, not dotted. 5. Lecythidex, having a multilocular woody capsule, which either remains closed or opens by a lid, mona- delphous stamens, alternate, not dotted leaves; the stamens form a cup, which often grows out on one side, with a curious hooded appen- dage. Several of these tribes are made separate orders by Lindley, Miers, and others, There are 75 known genera, and upwards of 1800 species. Hxamples—Chamelaucium, Calytrix, Leptospermum, Mela- leuca, Metrosideros, Eucalyptus, Myrtus, Psidium, Eugenia, Caryo- phyllus, Barringtonia, Gustavia, Lecythis, Bertholletia, Napoleona (Belvisia), Asteranthus. Many of the plants of the order yield an aromatic volatile oil. This is particularly the case with those having pellucid dots in their leaves. Some yield edible fruits, others furnish astringent and saccha- tine substances. The leaves of species of Leptospermum and Mela- leuca aré used as tea in Australia. The leaves of Melaleuca Leucaden- dron, a tree of the Indian Archipelago, Malayan Peninsula, and Australia, yield the volatile oil of Cajuput. It is a very liquid oil, of a grass-green colour, having a pungent camphoraceous odour, and capable of dissolving caoutchouc. It is used medicinally as a stimu- lant and antispasmodic. Species of Hucalyptus constitute the gigantic gum-trees of Australia, some of which attain a height of 2-300 feet. Baron Mueller mentions specimens of Eucalyptus amygdalinus 400 feet high. They are remarkable for their operculate calyx, which may be considered as formed by several jointed leaves (like those of the orange), united throughout, and separating at the articulation in the form of a lid (p. 199). Their bark also separates remarkably in layers. They yield an astringent matter, which has been used for tanning. Eucalyptus resinifera, Brown Gum-tree of New Holland, furnishes Botany-Bay Kino, an astringent, resinous-like substance, which exudes in the form of red juice from incisions in the bark. A single tree will yield sixty gallons. E. mannifera gives a saccharine exudation resembling manna. A saccharine substance, mixed with cellular hairs, which arise from a cup-like body, is found upon the leaves of £. dumosa, It is called Lurp by the natives, and is produced by the attack of a species of insect belonging to the genus Psylla. Hucalyptus globulus, Blue Gum-tree or Fever Gum-tree, is said to take up moisture largely from marshy lands. It furnishes good timber, and has an astringent bark. It yields a fragrant oil, which is used as an embrocation. The wood of many species of Metrosideros is hard and dark-coloured. The flower-buds of Caryophyllus aromaticus (Eugenia caryophyllata), a tree which was originally a native of the Moluccas, but is now cultivated in the East and West Indies, consti- tute the Cloves of commerce. They have the form of a nail (French clow), and, when examined, are seen to consist of the tubular calyx with a roundish projection formed by the unopened petals. They 492 MYRTACEA-—ONAGRACEZ. contain a volatile oil, associated with resinous, gummy, and astringent matter. The oil is aromatic and acrid, and has been used as a condiment and a stimulant carminative. Some suppose that the name is derived from the Greek xaguépuAdrov, on account of the flower-bud being round like a nut (xdéguov), Pimento, Allspice, or Jamaica Pepper, is the berried fruit of Pimenta officinalis (Eugenia Pimenta, Myrtus Pimenta), a tree which is a native of the West Indies and Mexico. The fruit has an aromatic odour, and its taste combines that of cinnamon, nutmeg, and cloves ; hence the name Allspice. It contains an acrid volatile oil, to which its properties are due. Medicinally Pimento is sometimes em- ployed as a stimulant and carminative. The fruit of Bugenia acris is used for Pimento. Among the pulpy edible fruits of the order may be noticed Guavas and Rose-apples. The former are the produce of various species of Psidiwm, such as P. pyriferum, pomiferum, and Cattleyanum ; the latter are procured from species of Eugenia as £. Jambos and malaccensis. The fruit of Eugenia caulifora is eaten in Brazil, and that of £. Ugni in Chili. The berries of the common Myrtle (Myrtus communis) are also used as food. Punica Granatum, the Pomegranate-tree, is a native of the warmer parts of Asia and Northern Africa, whence it was introduced into Europe. It is the j7271 (Rimmén) of Scripture. It produces dark scarlet flowers, formerly called Balaustia, which have been used as an astringent. The fruit of the Pomegranate has given rise to much difference of opinion among botanists. It is composed, in the young state, of two rows of carpels, some of which are placed round the axis, and adhering to the bottom of the calycine tube, while others are placed outside, and adhere to the upper part of the tube. The subsequent contraction of the tube of the calyx, and the peculiar adhesion of the placentas, according to Lindley, account for the anomaly in the fruit (Balausta, p. 314). The rind of the fruit (malicorium) and the bark of the root are used as anthelmintics, especially in cases of tapeworm. Lecythis ollaria, a large Brazilian tree, yields the woody capsules called Monkey-pots, which open by circumscissile dehiscence. These seed-vessels seem to be formed in the same way as the calyx of Eucalyptus, the part where the lid separates indicating the articulations of the carpellary leaves. The seeds are eatable, and are relished by monkeys. The bark of the tree may be separated into numerous thin layers. Bertholletia excelsa, or, according to Miers, Bertholletia nobilis, is the source of the Brazil nuts. The amount exported from Para, and from Mandog on the Rio Negro, in six months in 1865, was about 2,500,000 of the fruits, or 50,000,000 of the seeds, occupying the bulk of 60,000 bushels. The seeds retain vitality long. Sapucaia nuts are the produce of Lecythis usitata of Miers. Order 75.— Onacracez (Onagraries), the Evening-Primrose Family. (Rolypet. Epigyn.) Calyx tubular, the limb having usually ONAGRACEA—HALORAGEACEAI—LOASACEZ, 493 4 (fig. 433 1, p. 245), sometimes 2, 3, or 6 divisions (fig. 630, p. 364), which cohere in various ways; wstivation valvate. Petals usually equal in number to the calycine segments, regular (rarely irregular), inserted into the tube of the calyx (fig. 433 p, p. 245); sstivation twisted. Stamens usually 4 or 8 (rarely 1 or 2, fig. 630, p. 364), epigynous (fig. 433 ¢, p. 245); filaments distinct ; pollen triangular, usually cohering by threads (fig. 396, p. 252). Ovary 2-4-celled (fig. 630, p. 364), adherent (fig. 433 0, p. 245), usually with an epigynous disk ; style filiform ; stigma capitate (fig. 433 s, p. 245) or A-lobed ; ovules (figs. 418 0, p. 239; 433 g, p. 245) indefinite, rarely definite, anatropal. Fruit succulent or capsular, dehiscent or inde- hiscent, 1-2-4-celled. Seeds usually o, exalbuminous; embryo straight, with a long slender radicle pointing to the hilum, and short cotyledons (figs. 530, p. 296; 584, 585, 586, p. 331).—Herbs or shrubs, with alternate or opposite, simple, not dotted leaves, and with the parts of the flower usually tetramerous. They inhabit chiefly temperate regions, and are found abundantly in Europe, Asia, and America, and sparingly in Africa. Some yield edible fruits, as Fuchsia, others furnish edible roots, as Ginothera biennis. Many of them have mucilaginous properties, while a few are astringent. Trapa has unequal cotyledons. T. natans, Water Chestnut, and T. bicornis, remarkable for its horned fruit, both supply edible seeds. There are about 22 known genera, and upwards of 300 species. Zxzamples— CEnothera, Epilobium, Jussizea, Montinia, Fuchsia, Circea, Gaura, Trapa. ‘Order 76.—HaLoraGEAce#, the Mare’s-Tail Family. (Polypet. Epigyn.) Calyx with a minute limb, which is either 3-4-divided, or entire ; it is sometimes reduced toa mere rim. Petals epigynous or 0. Stamens epigynous, equal in number to the petals, or twice as many, rarely fewer; when the petals are wanting, stamens often 1 or 2. Ovary cohering with the tube of the calyx, with 1 or more cells, sometimes tetragonal or compressed. Style 0, what is frequently called the styles being the papillose stigmas, which are equal in number to the cells; ovules pendulous, anatropal. Fruit dry, indehiscent, membranous or bony, with 1 or more cells. Seed solitary or in pairs, pendulous ; albumen fleshy or thin ; embryo straight, or slightly curved, in the axis of the albumen ; cotyledons minute ; radicle superior, long. —Herbs or undershrubs, often aquatic, with large air cavities, having alternate, opposite, or whorled leaves, and axillary, sessile flowers, which are occasionally unisexual, They are found in ditches and lakes in various parts of the world. They have no properties of importance. There are 9 known genera and about 80 species. Examples—Hip- puris, Myriophyllum, Haloragis, Callitriche, Gunnera. Order 77,—Loasacea, the Chili-Nettle Family. (Polypet. Epigyn.) Calyx 4-5-parted, persistent, spreading in estivation. Petals 5, » 494. LOASACEH—CUCURBITACEA, cucullate, epigynous, alternate with the segments of the calyx, some- times with an inner row of 5, which are either similar to the outer or dissimilar ; estivation inflexed, valvate, or twisted. Stamens o, in several rows, distinct, or polyadelphous, each parcel being opposite the outer petals ; filaments subulate, unequal, the outer ones often sterile. Ovary inferior, 1-celled, with parietal placentas ; ovules anatropal ; styles combined into 1; stigma 1 or several. Fruit capsular or suc- culent, 1-celled. Seeds without an arillus ; embryo straight, in the axis of fleshy albumen ; cotyledons small, flat ; embryo pointing to the hilum.—Herbaceous plants, hispid with stinging hairs, having oppo- site or alternate exstipulate leaves, and axillary 1-flowered peduncles. They are American plants, chiefly distinguished for their stinging qualities, and hence the name of Chili-Nettle. The roots of Mentzelia hispida, a Mexican herb, are said to possess purgative qualities. There are 10 genera enumerated by authors, including 100 species. Zz- amples—Loasa, Mentzelia, Blumenbachia. Order 78.—Cucursitacza, the Cucumber Family. (Polypet. or Monopet. Epigyn. and Diclines.) Calyx 5-toothed (figs. 430 1, p. 245°; 713 ©), sometimes obsolete. Petals 5, distinct, or more or less united, sometimes scarcely distinguishable from the calyx, strongly marked with reticulated veins (fig. 430 p, p. 245), sometimes fringed. Stamens 5, distinct or united in one or three parcels, attached to the petals (fig. 713 ¢), anthers bilocular, sinuous (figs. 364, p. 223; 714 a; 389, p. 230), ovary (figs. 430 0, p. 245; 715 co), adhering to the tube of the calyx, Il-celled, formed by 3. car- pels, and having 3 parietal placentas (fig. 716, p. 495), which some- times project so as to join in the centre, the ovules remaining attached to the curved free edges; ovules solitary or indefinite (fig. 716), anatropal ; styles short ; stigmas very thick, velvety or fringed (fig. 715 s). Fruit a pepo (p. 314). Seeds flat and ovate (fig. 717), enveloped in a juicy or dry and membranous covering; testa coriaceous; albumen 0; embryo straight (figs. 717, ¢; 718); cotyledons leafy and veined; radicle next the hilum.—Herbaceous plants, with succulent stems, climbing by means of lateral tendrils, which are transformed stipules ; leaves alternate and palmate, covered with asperities ; flowers generally unisexual. They are natives of warm climates chiefly, and abound,in India. A few are found towards the north, in Europe and North America, and several are natives of the Cape of Good Hope. Those which are annuals readily submit to the climate of northern latitudes during the summer, and thus, though of tropical origin, they grow well in European gardens. There are nearly 70 known genera and about 470 species. Examples—Cucurbita, _ Cucumis, Momordica, Bryonia, Telfairia, Fevillea. A certain degree of acridity pervades the order, and many of the plants are drastic purgatives. In some cases, however, more espe- CUCURBITACEA, 495 cially under cultivation, the fruits are eatable. Instances of edible fruits are seen in Cucwmis Melo, common Melons > DOMAIN, Abbattichim of Scripture; Cucumis sativus, Cucumbers, p*xwp, Kishuim, of the Bible; Cucurbita Citrullus, Water Melon 3 Cucurbita Pepo, White Gourd; Cucurbita maxima, the Pumpkin; Cucurbita Melo-pepo, the Squash; Cucurbita ovifera, the Egg-gourd. The genus Cucumis contains the Melon and Cucumber, with edible fruits, , Fig. 714. Fig. 716. Fig. 717. Fig. 718. and the Colocynth, with purgative fruit. Much discussion has taken place in regard to the structure of the fruit in this genus, and in Cucurbitaceze in general. Some have considered it an anomaly in vege- table structure, from the apparent formation of the placenta and ven- tral suture, externally, as if the usual position of the carpels were reversed. It would appear, however, as shown by Lindley, that the placentas follow the ordinary law. They are parietal; and curve in a Figs. 713-718. Organs of fructification of Cucurbitacex. Fig. -713. Male flower of Cucumis sativus, Common Cucumber, laid open to show the interior of it. ¢, 5-divided calyx. p, United petals, by some considered as being an internal coloured calyx, 2, Epi- gynous stamens. Fig. 714. Stamen separated. jf, Filament. a, Long sinuous anther. Fig. 715. Female flower. co, Calyx attached to the ovary. p, United petals, s, Thick velvety stigmas. Fig. 716. Horizontal section of the ovary, showing its division into three, by projections from the parietal placentas, to which the indefinite ovules are attached, Fig. 717. Anatropal seed cut vertically. ¢, Spermoderm swollen at the chalaza,¢, e, Em- bryo, Fig. 718. Embryo separated. +, Radicle. c, Cotyledons. 496 CUCURBITACEAi—PAPAYACEA, peculiar way, bearing the seeds on their curvature ; at the same time prolongations are sent inwards, which often meet in the centre, Stocks and others consider the carpels as being involute, and they trace this involution particularly in Luffa pentandra, Luffa egyptiaca is called the Towel-gourd, as its split fruit is used as a flesh-brush. Sooly Qua is the fruit of this species of Luffa. Cucumis Colocynthis, or Citrullus Colocynthis, yields a globular fruit called Coloquintida, or Bitter Apple, the pulp of which constitutes the medicinal Colocynth. It is imported from the Levant and the coasts of the Mediterranean. It is used in the form of powder and extract as an irritant cathartic. The plant is supposed to be the nypp (Pakyoth), or Wild Gourd of Scripture. Momordica Elateriwm or Eeballium agreste (enBdrrw, I expel, in allusion to the expulsion of the seeds), the Wild or Squirting Cucumber, is so called on account of the force with which its seeds are expelled when ripe. The fruit, by a process of Endosmose going on in the cells, becomes distended, and ultimately gives way atithe weakest part, where the peduncle is united to it. In separating from the stalk, the elasticity of the parietes comes into play, so as to dis- charge the brown seeds and slimy juice through the aperture at the base of the fruit. The feculence which subsides from the juice con- stitutes the medicinal Elaterium, which is used in small doses of $4 a grain, as a violent cathartic, especially in dropsical cases. The active principle is Elaterin. The roots of Bryonia alba and dioica are also powerful purgatives. The fruit of various species of Gourd, as Cucur- bita Pepo, the White Gourd, and C. maxima the Red Gourd, C. ovifera succada, Vegetable Marrow, are used as potherbs; while C. Citrullus, the Water Melon, is prized for its cool refreshing juice. The fruit of Echinocystis lobata is the Mock-apple of Canada. Trichosanthes angwina, the Snake-gourd, is eaten in India, The fruit of Lagenaria vulgaris, in consequence of having a hard outer covering, is used as a vessel for containing fluid, after the pulp and seeds are removed. It is hence called Bottle Gourd. It is stated that poisoning has followed on the drinking of beer that had been standing in a flask made of one of those Gourds. Dr. Royle mentions that symptoms of cholera have been induced by eating the bitter pulp. The seeds of the plants in this order frequently supply a bland oil. The seeds of Telfairia pedata (Africa) are as large as Chestnuts, and are used as food. Order 79.—PapayacEm, the Papaw Family. (Monopet. Polypet. Epigyn. and Diclines.) Calyx minute, 5-toothed. Corolla monopetal- ous, inserted into the base of the calyx; in the male, tubular and 5- lobed ; in the female, divided nearly to the base into 5 segments. Stamens 10, inserted into the throat of the corolla; anthers bilocular, introrse, innate, dehiscing longitudinally. Ovary free, 1-celled ; ovules indefinite, attached to 5 parietal placentas ; stigma 5-lobed, lacerated. Fruit usually succulent and indehiscent, sometimes capsular and dehi- - PAPAYACEZ—PASSIFLORACEA. 497 scent, l-celled. Seeds «0 , enveloped in a loose mucous coat, parietal ; spermoderm brittle, pitted ; embryo in the axis of fleshy albumen ; cotyledons flat ; radicle slender, turned towards the hilum. ‘Trees or shrubs, not branching, with alternate lobed leaves, supported on long slender petioles, and with unisexual flowers. They are found in South America, and in other warm countries. One of the most important plants of the order is Carica Papaya, the Papaw-tree, which yields an acrid milky juice and an edible fruit. The juice of the unripe fruit and the seeds are said to act as anthelmintics. The juice is said to have the property of rendering meat tender. The order is by some considered to be a tribe of Passifloracee. The order has been divided into two tribes :—1. Caricez, corolla monopetalous, fruit succulent and indehiscent. 2. Modeccez, corolla monopetalous, fruit capsular and dehiscent. There are 6 known genera, including about 40 species. Hxamples—Carica, Modecca. Order 80.—PasstrLoRAcrs, the Passion-flower Family. (Polypet. Perigyn.) Sepals 5, combined below into a more or less elongated tube. Petals 5, perigynous, often with filamentous or annular pro- cesses on their inside, which appear to be an altered whorl or whorls of petals, occasionally wanting, imbricated in estivation. Stamens 5, monadelphous, surrounding the gynandrophore when present, rarely oo ; usually with processes from the thalamus, interposed between them and the petals; anthers dithecal, extrorse, versatile, dehiscing longi- tudinally ; pollen-grains sometimes bursting by opercula (fig. 388, p. 230). Ovary I-celled, often with a gynophore (p. 240); ovules, anatropal, oo; styles 3; stigmas dilated. Fruit often stipitate, 1-celled, sometimes 3-valved, opening by loculicidal dehiscence, or suc-_ culent and indehiscent. Seeds o, attached to parietal placentas, aril- late, or strophiolate ; spermoderm brittle and sculptured; embryo straight in the midst of thin fleshy albumen ; radicle pointing to the hilum.—Herbs or shrubs, often climbing, with alternate stipulate or exstipulate leaves. The order has been divided into three tribes :— 1. Paropsiex, plants not climbing, with a sessile ovary, arillate seeds, and exstipulate leaves. 2. Passiflorese, climbing plants with a stalked ovary, arillate seeds, stipulate leaves, and glandular petioles. 3. Malesherbiex, plants not climbing, with a stalked ovary, style below the apex of the ovary, strophiolate seeds, and exstipulate leaves. They are natives chiefly of warm climates, and are found in America, the East and West Indies. There are 12 known genera, and about 210 species. Eaamples— Paropsia, Smeathmannia, Passiflora, Tac- sonia, Malesherbia. : Considerable discussion has taken place as to the true nature of the calyx and corolla in Passifloraces. Lindley supports the view here given. Others consider the calyx as consisting of ten sepals in two rows, the inner more or less petaloid, and they look on the petals 2k 498 PASSIFLORACEZ—TURNERACEA—PARONYCHIACEA. as either wanting, or existing in the form of filamentous or annular processes. The name Passion-flower was given on account of a fancied resemblance in the flowers to the appearances presented at Calvary. In the five anthers the superstitious monks saw a resemblance to the wounds of Christ ; in the triple style, the three nails on the cross ; in the central gynandrophore, the pillar of the cross ; and in the fila- mentous processes, the rays of light round the Saviour, or the crown of thorns. Many of the plants, such as Passifora quadrangularis and edulis (Grenadillas), Paropsia edulis, and species of Tacsonia, yield edible fruits, the pulp or succulent arillus being fragrant and cooling. The root of Passiflora quadrangularis is said to be emetic and power- fully narcotic, on which account it is cultivated in several French settlements. It seems to owe its activity to a peculiar prin- ciple called Passiflorin. Other plants of the order are bitter and astringent. Order 81.—TuRNERACE, the Turnera Family. (Polypet. Perigyn.) Calyx with 5 equal lobes; estivation imbricated. Petals 5, peri- gynous, equal; estivation twisted. Stamens 5, perigynous, alter- nating with the petals ; filaments distinct ; anthers dithecal, innate, oblong. Ovary free, 1-celled, with 3 parietal placentas ; ovules oo, anatropal ; styles more or less cohering, or forked ; stigmas multifid. Fruit a 1-celled, 3-valved capsule, dehiscing only half-way down, in a loculicidal manner. Seeds crustaceous, reticulated, arillate on one side; embryo slightly curved, in the midst of fleshy albumen ; cotyle- dons plano-convex ; radicle pointing to the hilum.—Herbaceous or somewhat shrubby plants, occasionally with stellate pubescence, having alternate, stipulate leaves, and frequently two glands at the apex of the petiole. Seemann states that Turneraceze ought to be included in Pas- sifloracee. They are natives of the West Indies and South America. They are not put to any important use. Turnera opifera is astringent, and is employed in Brazil against dyspepsia. Turnera ulmifolia is considered tonic and expectorant. Genera, 3; species, 76. Examples —Turnera, Wormskioldia. Order 82.— Paronycuiacem, the Knotwort Family. (Polypet. Perigyn.) Sepals 4-5, distinct or cohering. Petals perigynous, be- tween the divisions of the calyx, usually inconspicuous, sometimes 0. Stamens usually perigynous, sometimes hypogynous, opposite to the sepals when equal to them in number, some of them occasionally wanting ; filaments distinct, rarely united ; anthers bilocular. Ovary superior, with one or more ovules; styles 2-3, distinct or combined, Fruit unilocular, either a utricle covered by the calyx, or a 3-valved capsule. Seeds either numerous, attached to a free central placenta, or solitary and pendulous from a long funiculus arising from the base of the fruit. Embryo more or less curved, lying on one side of the farinaceous albumen, or surrounding it.—Herbaceous or somewhat PARONYCHIACEAI—CRASSULACEA. 499 shrubby plants, with opposite or alternate, sometimes setaceous and clustered leaves, which are either exstipulate or have scarious stipules. Found in barren places in various parts of Europe, Asia, and North America. A slight degree of astringency pervades this order, and is the only sensible property that it is known to possess, This order is allied to Caryophyllacez in many respects. It is placed by some among the Monochlamydeous orders, as being allied to Chenopodiacez. The order has been divided into two sections :—1. Illecebres, with the embryo lying on one side of the albumen, and stipulate leaves. 2. Scleranthez, with a peripherical embryo and exstipulate leaves. There are 30 known genera, and nearly 120 species. Examples— Paronychia, Ilecebrum, Polycarpon, Corrigiola, Scleranthus. Order 83.—CrassuLAcE#, the Houseleek or Stonecrop Family (figs. 634, 635, p. 365). (Polypet. Perigyn.) Sepals 3-20, more or less united at the base (fig. 282 cc, p. 191). Petals equal to the sepals in number, inserted in the bottom of the calyx (fig. 282 pp, p. 191), either distinct or cohering in a gamopetalous corolla. Stamens inserted with the petals, either equal to them in number, and alternate with them (fig. 282 ¢ e, p. 191), or twice as many, those opposite the petals being shortest ; sometimes one or two rows of abortive stamens ; filaments distinct, or united, subulate, anthers bilocular, dehiscing longitudinally or transversely. Abortive stamens or scales (sometimes obsolete), at the base of each carpel (fig. 282 a a, p. 191). Carpels equal in number to the petals and opposite to them, 1-celled (fig. 282 o o, p. 191), sometimes consolidated ; styles several or combined ; stigmas pointed or 4-cornered ; ovules 00, or definite, anatropal. Fruit consisting of several follicles, dehiscing by the ventral suture, some- times by the dorsal suture. Seeds variable in number; embryo straight in the midst of fleshy albumen ; radicle pointing to the hilum—Her- baceous plants or shrubs, often succulent, with simple, entire, or pinnatifid, exstipulate leaves. They are found in the driest situations, as on rocks, walls, and sandy plains, in various parts of the world. Some of them are acrid, as Sedwm acre, Biting Stonecrop ; others are refrigerant, from the presence of an acid, such as malic-acid. Sem- pervivum tectorum is commonly known as the Houseleek. The fisher- men of Madeira rub their nets with the fresh leaves of the Sempervivum glutinosum, by which the nets are rendered as durable as if tanned, provided they are steeped in some alkaline liquor. Bryophyllum caly- cinum is remarkable for the property of producing germinating buds at the edges of its leaves (p. 118). In the leaves of some of the species, as Crassula profusa, C. lactea, and C. marginata, there are two kinds of stomata; one kind being of the ordinary size, and scat- tered over the leaves, the other being very minute, and raised on orbi- cular slightly convex punctiform disks, arranged in a row within the margin of the leaf. These disks consist of dense cellular tissue which 500 FICOIDEA) OR MESEMBRYACEZi—CACTACEA. terminates downwards in a conical form, and communicates with the peripheral ends of the veins, or the loose parenchymatous substance of the leaf. There are two tribes:—1. Sempervives, with numerous separate carpels. 2. Penthores, with pistil consolidated. There are 14 genera and about 400: species. LExamples—Crassula, Sempervivum, Cotyledon, Sedum, Penthorum. Order 84.—Ficoipr@ or MrsemBryace, the Fig-marigold and Ice-plant Family. (Polypet. Perigyn.) Sepals definite, usually 5, but varying from 4-8, more or less combined at the base, adherent to the ovary or distinct from it, equal or unequal; stivation valvate or im- bricate. Petals indefinite, coloured, sometimes 0. Stamens ‘perigyn- ous, distinct, definite or indefinite ; anthers oblong, incumbent, Ovary usually many-celled ; stigmas several, distinct ; ovules 00, anatropal or amphitropal, attached by cords to the placenta, which is either central or parietal, Fruit a many-celled capsule, opening in a stellate or circumscissile manner at the apex, or an indehiscent nut. Seeds 00, rarely definite or even solitary ; embryo curved or spiral, on the out- side of mealy albumen; radicle next the hilum.—Herbaceous or shrubby succulent plants, with opposite or alternate simple leaves. They are found in warm regions chiefly. The greater part of them grow at the Cape of Good Hope. The order has been divided into three tribes :—1. Mesembryeze, numerous conspicuous petals, many- celled capsule, with stellate dehiscence. 2. Tetragoniew, petals 0, fruit woody and indehiscent. 3. Sesuvem, petals 0, capsule with circumscissile dehiscence. 4. Molluginesw, calyx 5-partite, petals 3-5 or 0, stamens sub-perigynous, fruit capsular, or with 2-5 cocci. There are 22 known genera and 450 species. Examples—Mesembry- anthemum, Tetragonia, Aizoon, Sesuvium, Mollugo. Some of them are used as articles of diet, as the leaves of Mesem- bryanthemum edule, Hottentot’s Fig, and Tetragonia expansa, New Zealand Spinach. Others yield soda, and have been employed in the manufacture of glass. Mesembryanthemum erystallinum, the Ice-plant, is remarkable for the watery vesicles which cover its surface, and which have the appearance of pieces of ice. Its.juice is said to be diuretic, and has been prescribed in dropsy and liver complaints. The seed- vessels of some species of Mesembryanthemum, as M. Tripolium, have the property of expanding in a star-like manner when put into water, and closing when dry. The flowers of many of the plants of the order exhibit the phenomenon of opening only under the influence of sun- shine, and closing in dull weather (p. 262). Leaves of Mesembryan- themum, called Pigs’-faces, are eaten with Kangaroo flesh in some parts, of Australia, as a substitute for salt. , Order 85.—Cacrace#, the Cactus or Indian Fig Family. (Poly- pet. Epigyn.) Sepals numerous, usually co, and confounded with the petals, adherent to the ovary. Petals numerous, usually indefinite, CACTACEA. 501 sometimes irregular, inserted at the orifice of the calyx. Stamens in- definite, cohering more or less with the petals and sepals ; filaments long, filiform ; anthers ovate, versatile. Ovary fleshy, inferior, unilo- cular ; style filiform ; stigmas numerous ; ovules oo , attached to parie- tal placentas, equal in number to the stigmas. Fruit succulent, 1- celled. Seeds oo, parietal, or, after losing their adhesion to the placenta, nestling in pulp, ovate or obovate; albumen 0; embryo straight, curved, or spiral; cotyledons thick, leafy, sometimes nearly obsolete ; radicle thick, obtuse, next the hilum—Succulent shrubs, with peculiar angular or flattened stems, having the woody matter often arranged in wedges. Leaves usually absent; when present, - fleshy, smooth, entire or spinous. Flowers sessile, sometimes showy. They grow in hot, dry,.and exposed places, and are natives chiefly of the tropical parts of America. Some grow rapidly on the lava in volcanic countries. There are two tribes:—1. Echinocactex, calyx tube produced beyond the ovary, stem with tuberculated ribs, or with elongated aculei, 2. Opuntiex, calyx tube not produced beyond the ovary, stem branching, articulated. There are 13 known genera and about 1000 species. Hxamples—Opuntia, Melocactus, Mammillaria, Echinocactus, Cereus, Epiphyllum, Pereskia, Rhipsalis. The plants of this order are remarkable for their succulence, ‘for the great development of their cellular tissue, and the anomalous forms of their stems, some of which attain a great size. In their structure numerous spiral cells are met with, and in many cases the fibre in these cells is interrupted so as to present thickened rings united by membrane. These rings, when the cells are macerated, can be ob- tained in a free state. Many of the plants in this order show a remarkable tendency to spiral development. The set, spines, and hairs, are sometimes arranged spirally, and in Cereus flagelliformis the cells of the setee have this tendency. Many of them yield an edible fruit, which is sometimes refreshing and agreeable, at other times insipid. The fruit of Pereskia aculeata, under the name of Barbados Gooseberry, is used in the West Indies as an article of diet. That of Opuntia vulgaris is known under the name of Prickly Pear. The juice of the fruit of some species is subacid, and has sometimes been used as a refrigerant. Cattle sometimes feed on the succulent stems in dry seasons. Some of the plants are noted as night-flowering (p. 262). Cereus grandiflorus expands its large white blossoms about 10 p.m. in our hothouses, and their beauty lasts only for the night. Such is also the’case with CO. MacDonaldie and C. nycticalus, A plant of the latter species, in the Glasgow Botanic Garden, began. to open its flowers between 7 and 8 pP.m., and they were fully opened at 10. The follow. ing were the numbers ‘and sizes of the various parts :— Length of the tube of the calyx , . ‘i 7 inches. Length of the petals - Fi 7 ‘ ‘ 43 ae 502 GROSSULARIACEA OR RIBESIACEE—SAXIFRAGACEA, Length of the style . i . : 3 . 10 inches. Breadth of flower when fully expanded i MER gy Number of long sepals . . . ; - 75 Number of short sepals. . : - . é . 20 Number of petals c : : } . . 25 Number of stamens . P é i . 3 A . 400 Number of stigmas . , - 15 The size to which some of the Cactus family grow may be illustrated by a specimen of Echinocactus Viznaga, imported into Kew gardens from the mountains of San Luis, Potosi :— Weight of the plant a ‘ ‘ 5 2 718 Ibs. Height from surface of the eart s fs : 4 44 feet. Measured over the top from the ground on each side 10 feet 9 inches, Circumference at 1 foot fron the ground 2 "i 8 feet 7 inches, Number of deep angles or cost . 4 ‘ ; 44 “ Number of spines . 3 : : - 8800 In Brazil, some epiphytic Cactuses are met with ; and there are some species described by Gardner as attaining a height of thirty feet, with a circumference of three feet. Opuntia cochinellifera, and other species, are infested by the Coccus Cacti, or the cochineal insect, which feeds upon them. The plants are cultivated in what are called nopaleries, for the sake of the insect, the females of which, when dried, consti- tute the cochineal of commerce. Order 86.—GRossULARIACEH or Rripestace#, the Gooseberry and Currant Family. (Polypet. Epigyn.) Calyx 4-5 cleft, regular, coloured. Petals minute, perigynous, equal in number to the seg- ments of the calyx, and alternate with them. Stamens 4-5, alternate with the petals, and inserted into the throat of the calyx ; filaments short ; anthers dithecal. Ovary unilocular, adherent to the tube of the calyx; ovules co, anatropal, attached to two opposite parietal placentas ; style single, 2-4 cleft. Fruit a 1-celled berry, crowned with the remains of the flower. Seeds oo, immersed in pulp, and attached to the placentas by long thread-like funiculi; spermoderm gelatinous externally; albumen horny; embryo straight, minute; radicle pointing to the hilum.—Shrubs, with alternate lobed leaves, having a plicate vernation. They are natives of temperate regions, and are found in Europe, Asia, and America. Many yield edible fruits, which sometimes contain malic acid. The various kinds of Gooseberry (Ribes Grossularia) and Currant (Ribes rubrum and nigrum) belong to this order. The black currant possesses tonic and stimulant properties. On the under surface of its leaves and flowers fragrant glands may be perceived. The order is considered by some as a tribe of Saxifragacee. It contains 2 or 3 genera, and nearly 60 species. Hxample—Ribes. : Order 87.—Saxirracacesm, the Saxifrage Family. (Polypet. Perigyn.) Calyx superior, or more or less inferior (fig. 431 cc, p. 245) ; sepals usually 5, more or less cohering at the base. Petals ° SAXIFRAGACEA, 503 usually 5, perigynous, alternate with the lobes of the calyx (fig. 431, pp, p. 245), rarely 0. Stamens perigynous (fig. 431 ¢, p. 245), 5-10 or ©, in 1 or more rows; anthers bilocular, with longitudinal or porous dehiscence. Disk often present, either annular or scaly. Ovary more or less completely united to the tube of the calyx, consisting usually of two carpels, cohering by their face (figs. 431 ; 432 o, p. 245), but distinct and diverging at the apex; styles as many as the earpels, distinct (fig. 432 ¢, p. 245) or combined ; stigmas capitate (fig. 432 s, p. 245) or clavate. Placentas (fig. 432 p, p. 245) mar- ginal (basal or apicilar), rarely central. Fruit generally a 1-2-celled capsule, the cells dehiscing at the ventral suture, and often divari- cating when ripe, sometimes baccate. Seeds usually oo , rarely defi- nite ; spermoderm often reticulated ; embryo small, in the axis of fleshy albumen ; radicle pointing to the hilum—Shrubs or trees, or herbs, with alternate or opposite, usually exstipulate leaves. They are generally natives of temperate climates, and some of them character- ise alpine districts. The order has been divided into the following sub-orders :—1. Escallonieze, petals and stamens 5; ovary inferior ; style simple ; albumen oily ; evergreen shrubs, with alternate, simple, exstipulate leaves, found in the temperate regions of South America, often at a great elevation. 2. Cunonies, petals 4-5 or 0; stamens 8-10 or o ; ovary half inferior ; styles 2, distinct or combined ; trees or shrubs, with opposite leaves, having interpetiolary stipules ; found in South America, the East Indies, south of Africa, and Australia. 3. Hydrangez, petals 4-6 ; stamens 8-12 or «0; anthers sometimes biporose ; ovary more or less inferior ; styles 2- 5, usually distinct ; shrubs with “opposite, sometimes whorled, exstipulate leaves, and inflorescence frequently cymose, with the exterior flowers sterile and dilated ; found chiefly in the temperate parts of Asia and America. 4, Saxifragese, petals 5 or 0; stamens 5-10; ovary more or less adherent ; styles usually 2, and distinct; herbs, with alternate, usually exstipulate leaves, found in the mountainous regions of Europe, etc. Few of the plants are put to any use. Some of them are astringent, and used for tanning ; others have bitter tonic proper- ties. The glutinous exudation of a few of them is acrid. Escallonias may be said to represent shrubby Saxifrages. They inhabit chiefly the mountainous districts of Chili and the southern part of South America. Escallonia macrantha and rubra are grown in the milder parts of Great Britain. The leaves of Hydrangea Thunbergti furnish tea of a very recherché character, bearing the name of Ama-tsja in Japan. In the entire order there are 60 known genera, and upwards of 500 species. Some include Philadelphacez and Francoacez in this order. Cephalotus is considered as an anomalous apetalous genus of the order. It is allied also to Crassulacew, and by some authors it is in- cluded in a separate order—CEPHALOTER, There is only one species, 504 BRUNIACEZI—HAMAMELIDACE: C. follicularis, which inhabits §.W. Australia. Its leaves are arranged in arosette at the top of the rhizome, They are of two kinds, one flat, with a somewhat cylindrical dilated petiole, and the other true ascidia (pitchers) formed by the petiole, which is dilated at the top into two lips, the lower being larger and cup-like, and opening by a circular orifice, the upper being smaller, and acting as a lid to the cup. The pitchers contain a secretion. Ezamples—LEscallonia, Brexia, Itea, Cunonia, Weinmannia, Hydrangea, Bauera, Saxifraga, Astilbe, Chrysosplenium, Heuchera. Order 88.—Brun1ace&, the Brunia Family. (Polypet. Epigyn.) Calyx 5-cleft ; sestivation imbricated. Petals inserted in the throat of the calyx, and alternate with its segments. Stamens alternate with the petals, arising from them, or from a disk surrounding the ovary; anthers introrse, 2-celled, with longitudinal dehiscence. Ovary usually adherent to the tube of the calyx, and 1-3-celled ; ovules anatropal, suspended, 1 or 2 in each cell ; style simple or bifid; stigmas 1-3. Fruit either bicoccous and 2-celled, or indehiscent and l1-celled, crowned by the persistent calyx. Seeds solitary or in pairs, suspended, sometimes with a short arillus; embryo minute, at the base of fleshy albumen ; cotyledons short and fleshy ; radicle conical, next the hilum.—Branched heath-like shrubs, with small, imbricated, rigid, and entire leaves, and small, often capitate flowers. They are natives principally of the Cape of Good Hope, and have no important properties. There are 10 known genera and about 40 species. Examples—Brunia, Staavia, Berzelia. Order 89.—H aMaMELIDACE®, the Witch-hazel Family. (Polypet. Epigyn.y Calyx 4-5-lobed or truncate. Petals 4-5 or 0, inserted on the calyx, alternating with the calycine segments. Stamens twice as many as the petals, in two rows, one of which alternates with the’ petals and is fertile, the other is opposite to them and sterile ; anthers bilocular, introrse. Ovary adherent, 2-celled ; ovules solitary, or seve- ral (in Bucklandia and Sedgwickia), pendulous or suspended ; styles 2. Fruit a 2-celled, 2-valved capsule, opening by loculicidal dehiscence. Seeds pendulous; embryo straight, in the axis of fleshy albumen; cotyledons leafy ; radicle superior.—Shrubs or small trees, with alter- nate, petiolate, feather-veined, and stipulate leaves, and small axillary, bracteated, often unisexual flowers. They are found in various parts’ of Asia, Africa, and America. The seeds of Hamamelis virginica are used as food, while its leaves and bark are astringent and acrid. Inquidambar orientalis yields liquid storax, which is used as a cure for scabies. The resins yielded by Liquidambar styraciflua, Formosana, and altingiana, are also used as fragrant balsams. By some authors these plants are placed in a Monochlamydeous order, Balsamiflue or Altingiacee. Authors notice 15 genera, including 30 species. Ez- amples—Hamamelis, Fothergilla, Bucklandia, Rhodoleia, Liquidambar. UMBELLIFERA. 505 Order 90.—UmpexiirErs, the Umbelliferous Family (figs. 719- 725), Apiacess of Lindley. (Polypet. Epigyn.) Calyx superior, 5- Fig. 724. Fig. 725. ; Figs. 719-723. Organs of fructification of Daucus Carota, common Carrot, to illustrate the natural order Umbellifere. Fig. 719. Diagram of the flower, with a 5-toothed calyx, 5 inflexed petals, 5 stamens, and fruit formed by 2 carpels, with primary and secondary ridges, valleculz, commissure, and flat albumen. Fig. 720. The flower viewed from above, show- ing the petals with inflexed points and 5 stamens. ge, Epigynous disk or stylopod. Fig. 721. Vertical section of the flower. p, Petals with inflexed points. ¢, Stamens, one incurved at the apex. vu, Ovary formed by two carpels, adherent to the calyx throughout. s, Styles and stigmas. ge, Epigynous disk or stylopod. Fig. 722. Horizontal section of the fruit (cremocarp) with bristly ridges. Fig..723. Vertical section of the cremocarp. /f, Pericarp. g, Seed. pp, Flat perisperm. e, Embryo. Fig. 724, Perfect flower of Narthex Asafcetida, with obsolete 5-toothed calyx, 5 oblong petals, one showiug inflexed point, 5 stamens, epigynous disk, and 2 slightly-curved styles. Fig. 725. Pistillate flower of ditto, with obsolete-lobed calyx, 2 deflexed styles surmounting the cremocarp. 506 UMBELLIFERA, toothed or entire. Petals 5, inserted on the outside of a fleshy epi- gynous disk, often with inflexed points (figs. 306, p. 201; 720). Stamens 5, alternate with the petals, incurved in xstivation (figs. 720, 721, 723). Ovary inferior, 2-celled, crowned with a double disk or stylopod (fig. 721 ge); ovules solitary, pendulous; styles 2, distinct (fig. 550 ss, p. 306); stigma simple. Fruit (figs. 722, 723) a cremocarp (p. 311), consisting’ of two achenia (mericarps or hemicarps), which adhere by their face (commissure) to a common axis (carpophore), from which they separate, and are suspended when ripe (figs. 550 a, p. 306 ; 725); each mericarp is traversed“ by five primary longitudinal ridges (juga), and often by four alternating secondary ones, the ridges being separated by channels (vallecule). In the substance of the pericarp there are frequently vitte containing oil, which are usually opposite the channels. Seeds pendulous (fig. 723 g), usually adherent to the pericarp, rarely loose ; embryo minute, at the base of abundant horny albumen (fig. 723 ¢) ; radicle pointing to the hilum.—Herbace- ous plants, often with hollow and furrowed stems, with alternate, rarely opposite, variously divided, sheathing leaves (which sometimes assume the appearance of phyllodia), and with umbellate, involucrate flowers (fig. 262, p. 179). They are found chiefly in the northern parts of the northern hemisphere. In warm countries they occur at high elevations. The order has been divided according to the number and size of the pericarpial ridges, the presence or absence of vitte, and the form of the albumen. The following sections are given by old authors, but they are not sufficiently definite for the purpose of classi- fication :—1. Orthosperme (és, straight, and omégua, seed), albumen flat on the inner face, neither involute nor convolute. 2. Campylo- sperma (xa» 67° 40’ ,, a5 és 5000 ,, Scotch Fir ,, s, 70° 95 és sy 6000 ,, Birch 33 » 70°40’ ,, eS 35 6400 ,, 2.—EFFECcTS OF MoIstuRE. The absolute and relative quantity of moisture in the air has a decided effect on the distribution of plants. Nothing checks vegetation more than extreme dryness. Hence the barrenness of those hot sandy deserts which exhibit only an arid waste, without a single blade of grass to relieve the eye of the weary traveller. In warm and dry climates, succulent plants occur, with hard epidermal coverings, capable of resist- ing the effects of evaporation and transpiration. Among these may be noticed Cactacee, Mesembryacese, Euphorbias, and some of the Aloe tribe. In the districts of Australia, where a dry climate prevails, many plants, such as Proteas, Banksias, and leafless Acacias, have hard and dry foliage, capable of enduring much drought without injury. In warm climates the effect of the dry season on vegetation is very remarkable. This season may be said to correspond with our winters. In some parts of South America, where no rain falls for eight months of the year, the leaves during the dry season fall, buds are developed in their axils, and it is only when the wet season arrives that the trees become clothed with verdure, and the herbage appears. Forests appear to keep up the humidity of the atmosphere in a country, and thus have a powerful influence on the climate, 3.—Errects oF Sort, Lieut, AND OTHER AGENTS. The physical localities in which plants grow vary considerably. These variations are connected with the dryness and moisture of the soil, as well as with its mechanical and chemical composition. Some plants are fitted to grow in water, others in marshes ; some grow in peaty soil, others in sandy soil. Thurmann has endeavoured to show that the nature of the soil, whether siliceous, clayey, calcareous, or saline, has an effect in modifying the vegetation. Prof. E, Forbes states that in Lycia he could easily distinguish the serpentine from DISTRIBUTION AS AFFECTED BY MOISTURE AND HEAT. 663 the limestone, not merely by their geological characters, but also by the disposition of the arborescent vegetation, On the serpentine, usually pines only grew, and never in thick forest masses, but scat- tered ; whereas the limestone bore thick clustered oaks and a luxu- riant underwood, with now and then clumps of lofty pines. In the low countries near the sea, the serpentine was marked by Senecio squalidus, a little Erophila, and Cheilanthes odora ; while on the lime- stone, Acrostichum lanuginosum was a conspicuous fern. Some of the rare alpine plants of Scotland grow on serpentine. A crumbling mica- ceous soil favours the growth of alpine species in Britain. Lichens seem to be often associated with special kinds of rocks. Alphonse De Candolle has recently promulgated the following views in regard to the distribution of plants in connection with heat and moisture:—The present distribution of plants over the globe depends on two principal factors—1. The phenomena of distribution in other geological epochs than our own. 2. The physical condition, temperature, moisture, etc., now existing. The climate in any region now-a-days may bé the same as that which prevailed elsewhere at a remote period. The vegetation of the Mediterranean region, as we now know it, once extended as far as Paris, and the present Arctic and Alpine floras were once spread over a large extent of Europe. The flora of the tropics once extended as far as London, as proved by the fossils of the tertiary epoch. De Candolle establishes five groups of plants according to their physical requirements. 1. Megatherms (méyéc, great, déeun, heat), plants requiring a large amount of heat and moisture. Megathermal plants at the present day exist in the tropics, in the plains, and in the hot damp valleys, as far as the 30th parallel. Mean temperature never below 86° F.,* and moisture never deficient. The fossil predecessors of existing Megatherms are much more widely diffused than their descendants. In a very early period they were distributed all over the globe, but since the commencement of the tertiary epoch they have been concentrated more and more in the equatorial regions. The species of this epoch vary in different regions of the globe. They consist mainly of woody plants and climbers, with persistent leaves. Epiphytes abundant in the forests. Such orders as Anonacez, Ternstreemiacee, Guttiferee, Aristolochiacez, and Piperacee, are amongst the most characteristic plants. 2. Xerophiles, or Xerophilous plants (Zegés, dry, piAéw, I love), a group of plants requiring as much heat, but less moisture. At the pre- sent day such plants thrive in the hot and dry regions between 20th to 25th and 30th to 35th degrees of latitude, z.¢. in the dry regions extend- ing from California and Texas to Mexico, from Senegal to Arabia and * Not a few of the temperatures which follow, as given by De Candolle and Schouw, now require revision, and we hope that some meteorologist will soon adequately discuss the subject from the most recent observations. 664 DISTRIBUTION AS AFFECTED BY MOISTURE AND HEAT. the Indies, in South Australia,”"at the Cape of Good Hope, and the dry portions of La Plata, Chili, Peru, and the Andes. Xerophilous plants occur likewise in Brazil, the Mediterranean region, some parts of India, China, etc. At the present day they are more widely distri- buted than the Megatherms. In this group are included many Com- posite, Labiate, Boraginaces, Liliacee, Palms, Myrtles, Euphor- biacese, etc. The most characteristic orders are—Zygophyllacee, Cactaceze, Mesembryanthemacex, Cycadacez, and Proteacex. Suc- culent plants abound—Cacti in America, Euphorbias in Aftica, Mes- embryanthemums at the Cape. The history of the fossil plants of these districts is very imperfectly known. 3. Mesotherms (uéooc, middle, and ééguy, heat), requiring a mo- derate degree of heat (mean annual temperature 59° to 68° F.) with a moderate degree of moisture. This division includes the majority of Mediterranean plants, plants of Northern India at low eleyations, plants of China, Japan, California, the Southern States of America, the Azores, and Madeira (including always the mountain plants of those districts), the plains of Chili, Tasmania, and New Zealand. Mesotherms are also met with on the lower slopes of tropical moun- tains. They include many plants with evergreen foliage, Laurels, Magnolias, Campanulas, Cistuses, many Leguminosee, Composite, Cupuliferee, Labiate, and Cruciferee. Analogous forms existed in the early tertiary period in Spitzbergen and North America, while the floras of Japan and of the United States were probably nearly identical. 4, Microtherms (:xe6c, small, and ééeu, heat), requiring com- paratively little heat (mean annual temperature, 57° to 32° F.) Species of our European plains and of the Alps, those of Asia, between the Caucasus and the Himalayas, those of North America, 38° and 40° north, and between 60° and 66° of the Southern Hemisphere, plants of Chili, Cape Horn, Kerguelen Land, and the mountains of New Zealand. Herbaceous perennials abound, deciduous trees and coni- fers. The ground now covered by Microthermal plants was previously occupied by Mesotherms and Megatherms, which were extinguished by the glacial epoch. 5. Hekistotherms (jxsoroc, very , little, déguy, heat). Plants of arctic and antarctic regions, and upper portions of mountainous or temperate regions. They can bear a continued period of darkness, either from being covered with snow, or from their nearness to the poles, where daylight is absent for many months.’ Mosses, Lichens, Coniferze, Caryophyllacez, Rosaceze, Saxifragacese, are well represented. 6. Megistotherms (uéysoros, greatest, d2gun, heat). Plants requiring an extreme degree of heat (more than 86° F. mean annual tempera- ture). This is not geographical, Algse, Ferns, and Lycopods of the coal period may have been their representatives in former ages, as the Algze of hot springs are now-a-days. £ BOTANICAL LOCALITIES OR STATIONS. 665 The following is a division of plants according to the botanical stations or physical localities in which they grow, whether placed there by nature or by art :— A.—Plants growing in Water, whether Salt or Fresh. - 1. Marine plants, such as Seaweeds, Lavers, etc., which are either buried in the ocean, or float on its surface: also, such plants as Ruppia and Zostera, grass- wrack. In the Sargasso Sea there are floating meadows of Sargassum bacciferum, gulf-weed. This sea extends from 22° to 36° north lat., and from 25° to 45° west long. from Greenwich, and extends over 40,000 square miles. 2. Maritime or saline plants. These are plants which grow on the border of the sea, or of salt lakes, and require salt for nourishment, as Salicornia, glasswort, Salsola, saltwort, Anabasis. Such plants are often called Halophytes (GAs, salt, and guréy, a plant). Under this head may be included littoral and shore plants, such as Armeria, sea-pink, Glaux, sea-milkwort, and Samolus, brookweed. 8. Aquatic plants, growing in fresh water, either stagnant or running; as . Sagittaria, arrowhead, Nymphoea, water-lily, Potamogeton, pondweed, Subularia, awlwort, Utricularia, bladderwort, Stratiotes, water-soldier, Lemna, duckweed, Pistia, Confervee, Oscillatoric, and Ranunculus fluitans. Some of these root in the soil, and appear above the surface of the water; others root in the soil, and remain submersed, while a few swim freely on the surface without rooting below. 4, Amphibious plants, living in ground which is generally submerged, but occasionally dry, as Ranunculus aquatilis and sceleratus, Polygonum amphibium, Nasturtium amphibium. The form of the plants varies according to the degree of moisture. Some of these, as Limosella aquatica mudwort, grow in places which are inundated at certain periods of the year ; others, such as Rhizophoras mangroves, and Avicennias, form forests at the mouths of muddy rivers in tropical countries. B.—Land Plants which Root in the Earth and Grow in the Atmosphere. 5. Sand plants ; as Carex arenaria, Psamma arenaria, Elymus arenarius, and Calamagrostis arenaria, which tend to fix the loose sand, Plantago are- naria, Herniaria glabra, Sedum acre, biting stonecrop. 6. Chalk plants ; plants growing in calcareous and cretaceous soils, as some species of Ophrys, Orchis, and Cypripedium. 7. Meadow and pasture plants ; as some species of Lotus, bird’s-foot trefoil, a great number of grasses and trefoils, the daisy, dandelion, and buttercups. 8. Plants found in cultivated ground. In this division are included many plants which have been introduced by man along with grain; as Centaurea Cyanus, corn blue-bottle, Sinapis arvensis, common wild mustard, Agrostemma, corn-cockle, several species of Veronica and Euphorbia, Lolium temulentum, Convolvulus arvensis, Cichorium Intybus ; also plants growing in fallow ground, as Rumex 238 Lower Red pene Triassic. 93 Total . . 5131 The following i is a general statement of the number of fossil genera and species belonging to the different classes and sub-classes of the vegetable kingdom :— Genera, Species. DicoTyLEDoNES—Dialypetalee é i 200 1397 Gamopetale : 77 350 ————-— Apetale Angiospermez & 75 941 Gymnospermese : : 89 680 MonocoryLeponEs—Petaloidez ; 51 285 ——_———_—— Glumifere : 11 94 ACOTYLEDONES—Acrogene . ‘ 184 973 = -—— Thallogene . 53 411 740 5131 ORDERS OF FOSSIL PLANTS. 725 Class I.—DicoTyLEDoNEs, 1. Thalamifore. Ranunculacer. Nympheacee. Byttneriaceze. Sapindacee. Magnoliaceze. Cruciferze. Tiliacez. Vitacee. Anonacez. Cistaceze, Ternstroemiaceze. Pittosporacez. Menispermacez. Violaces. Malpighiacez. Zygophyllacee. Berberidacez. Malvacee, Aceracee. Xanthoxylacee. 2. Calyciflore, Polypetale. Celastraceze. Burseraces, Melastomaces. Saxifragaces. Hippocrateacez. Leguminosee. Myrtacez. Hamamelidaces. Rhamnacee. Rosaceee. Halorageacese. Umbelliferee. Anacardiacez, Combretaces. Crassulaceze. Araliaces. Cornacee. 3. Calycifiore, Gamopetale. Caprifoliacese. | Rubiacez. | Valerianacee. | Composite. Vacciniaceee. 4. Corollifiorce. Ericacez. Oleacese. Bignoniacez. Solanaces. Aquifoliaceze. Asclepiadaceze. Convolvulaceze. Scrophulariacez. Sapotacee. Apocynacez. Cordiaceee. Verbenacez. Myrsinacee. Gentianacee. Boraginacee. 5. Monochlamydew, Angiospermec. Nyctaginacese. Thymeleaces. Euphorbiacee. Myricacez. Chenopodiacese, Samydacez. Urticacez. Casuarinaceze. Polygonacez. Homaliacee. Ulmaceze. Betulacee. Lauracee. Santalaceze. Moraceee. Platanacez. Proteacez.- Loranthacee. Monimiacez. Corylacez. Elzagnaces. | Aristolochiaceze. Salicaceze. Juglandacese. 6. Monochlamydece, Gymnospermec. Conifereze. | Cycadacez. Class II.—MonocorTyLEDONES. 1. Petaloidec. Hydrocharidacez. | Iridacee. Smilaceze. Typhacez. Zingiberaceze. Amaryllidacez. Juncacer. Aracee. Marantacez. Bromeliacese. Palmee. Naiadacez. Musacer. Liliaceze. Pandanacez. 2. Glumifere. Cyperacee. | Graminez. Class III.— AcoTyLEDoNEs. 1. Acrogene. Equisetacez. Rhizocarpee. Musci. Filices. Lycopodiacee. Hepatice. 2. Thallogence. Lichenes. | Fungi. | Characeze. | Alga. 726 FOSSIL PLANTS IN DIFFERENT STRATA. Foss, PLants in DirFERENT SrRatTa.—tThe plants in the strati- fied rocks are either of a marine, fluviatile, lacustrine, or terrestrial nature, according to the state of the globe at the period of their depo- sition. The condition of the strata as regards fossils may depend in some measure on the depth at which they were deposited under the waters of the globe. The state of preservation depends much on the nature of the plant in regard to its anatomical structure. Cellular plants, which are easily destroyed, have in a great measure disap- peared, while plants which resist well the decomposing action of water and other agents, suchas ferns, occur in great abundance. In the Silurian system, the fossils consist chiefly of invertebrate animals. Lignite has been detected by Hugh Miller in the Old Red Sandstone of the north, and has been referred to some coniferous plants by Nicol. In the Carboniferous system fossil plants occur in vast quantity. With the Paleozoic series one great epoch in the Rock formations was concluded, and a change took place so as to usher in the Secondary series. In the Triassic system the fossil remains are few and local, while in the Jurassic and Cretaceous systems they are much more numerous, With the Secondary series of strata a general condition of the globe ended, and a new one commenced with the Tertiary strata. In these we meet with fossil remains nearly resembling or identical with the existing races. The names given to the groups indicate this. In the Eocene group (4#¢, dawn, and xouvés, fresh) we meet with a certain proportion of living shells. In the Miocene (ueiw, less) the number of living species increases, although still less in number than the extinct ones; while in the Pliocene (+A¢/wv, more) the recent shells outnumber the extinct ones. The differences between the organic contents of one system and another are in proportion to the interval of geological time elapsed between them ; and the older the rocks the more are the fossils distinct from the plants of the present day. The systems of organic life have been adjusted to the condition of land and sea. The number of fossil plants known to M. Adolphe Brongniart, in 1836, was 527. In 1845, Goeppert and Bronn stated the number to be 1792; Unger, in 1850, described 2421; while Schimper, in 1874, enumerates upwards of 5000. When we consider that of the 130,000 plants which may be supposed to constitute the present Flora of the globe, a large proportion consists of cellular plants, which would disappear in the process of fossilisation, it would seem that the total number of known fossil species bears a considerable proportion to those now existing. It is impossible in a short treatise like this to allude to many of the fossil species of plants. It will be sufficient to indicate some of the more important genera, and to give an account of their struc- ture and conformation. REIGN OF THE ACROGENS. 727 Brongniart, from the investigation of the several geological for- mations, has arrived at the conclusion that three distinct periods of vegetation can be established. In the most ancient periods there is a predominance of acrogenous cryptogamous plants (Ferns, Lycopodiacez, Equisetacez, and their allies) ; later, the predominance of gymnosper- mous dicotyledons (Cycadacez and Coniferz) ; and, in the last place, the appearance and predominance of angiospermous plants, both dicotyledons and monocotyledons. These differences led Brongniart to recognise three long periods of vegetable growth, which he terms the reign of the Acrogens, the reign of the Gymnosperms, and the reign of the Angiosperms, as indicative of the successive predominance of each of these three great divisions of the vegetable kingdom, rather than the complete exclusion of the others. Each of these three kingdoms is commonly subdivided into many periods, during which traces of the same family and genera are discoverable. These periods comprehend many epochs, during which vegetation does not appear to have undergone any notable changes. Materials are often wanting to establish precisely these subdivisions, either from a want of accuracy in determining the exact geological position of beds en- closing vegetable impressions, or because the division of the various species in the different beds of the same formation has not been care- fully established. Brongniart proposes the following general division of the fossil kingdom :— I. Reren oF THE ACROGENS. CARBONIFEROUS AND PERMIAN PERIODS, During these periods there seems to be a predominance of Ferns, a great development of Lycopodiacex, arborescent forms of Lepidodendron and Sigillaria, Gymnosperms allied to Araucaria, and anomalous Gymnosperms, as Néggerathia. II, Reien oF THE GYMNOSPERMS. TRIASSIC AND JURASSIC PERIODS. Here we meet with numerous Coniferee and Cycadacez, while Ferns are less abundant. III. REIen oF THE ANGIOSPERMS, CRETACEOUS AND TERTIARY PERIODS, This is characterised by the predominance of Angiospermous Dicotyledons, a class of plants which constitute more than three-fourths of the present vegetable productions of the globe, and which appear to have acquired a predominance from the commencement of the Tertiary formations. These plants appear sparingly even at the beginning of the chalk formation in Europe, but are more abundant in this formation, as developed in North America. Schimper divides Brongniart’s Reign of Acrogens into two :—1. The Reign of Thallassophytes or of Cellular Cryptogams, especially 728 FLORA OF THE PRIMARY OR PALASOZOIC PERIOD. Marine alge ; including the lower Permian, Silurian, and Cambrian rocks. 2. The Reign of Vascular Cryptogams. Williamson thinks that these divisions of Brongniart cannot be adhered to. He finds that there are fossil plants which show an evident transition from the Vascular Cryptogams to the Gymnosperm- ous Exogens, and that these divisions cannot be separated as regards fossil plants. He suggests the division of Vascular Cryptogams into two :—-1. An Exogenous group, including Lycopodiacerw, Equisetaceze, and the fossil Calamitacee. 2. An Endogenous group, containing the Ferns. The former uniting the Cryptogams with the Exogens through the Cycadaceze and Coniferz ; and the latter linking them with the Endogens through the Palme. I.—FLORA OF THE PRIMARY OR PALAOZOIC PERIOD. Reien or AcROGENS. (According to BRonenraRrT.) In this period Acrogens and Gymnosperms are found to have existed simultaneously, the former predominating over the latter in number and size. The number of the Fern family, the great develop- ment of the Lycopodiacez and Equisetacex, are the most prominent characters of this epoch. Other anomalous families belonging to the Gymnosperms are also met with, which differ from actually existing orders. Fiona OF THE SILURIAN AND CampBrian Systems.—In the lower Paleozoic strata the plants which have been detected are few. In the Silurian and Cambrian systems we meet with the remains of ancient marine plants, as well as a few terrestrial species. Even in the still older Laurentian rocks, if the remarkable structure known as Hoxoon canadense be considered, as it generally is, an animal, the ex- istence of contemporary plants may be inferred, inasmuch as without vegetable life animals could not obtain food. In the Lower Silurian or Grauwacke, near Girvan, Hugh Miller has found a species resem- bling Zostera in form and appearance. In the Lower Old Red Sandstone of Scotland, he has detected Fucoids, a Lepidodendron, and Lignite with a distinct Coniferous structure resembling that of Araucaria, besides a remarkable pinnate frond. In the middle Old Red of Forfarshire, as seen in the Arbroath pavement, he has col- lected specimens of a peculiar plant, bearing organs which resemble in appearance small receptacles of Nelumbium, besides a Fern with reniform pinnz and a Lepidodendron ; while, in the Upper Old Red, near Dunse, a Neuropteris, like N. gigantea of the Coal-measures, FOSSIL FLORA OF THE CARBONIFEROUS SYSTEM. 729 and a Calamite have been discovered by him. In the Old Red Sand- stone rocks at Oporto, Bunbury detected Pecopteris Cyathea, P. muricata, and Neuropteris tenuifolia—ferns allied to those of the Coal-measures. A still more extensive and varied land flora of Devonian age (or Erian, as he calls it) has been described and illus- trated by Principal Dawson from the rocks of that period occurring in Canada; and during a recent visit to Britain he has correlated many of the fragments collected by Miller, Peach, and ‘others, with the American species he has described. The following are some of the fossil plants from beds older than the Carboniferous system :— Prototaxites Logani, Dadoxylon ouangondianum, Calamites transi- tionis, Asterophyllites parvulus, Sphenophyllum antiquum, Lepido- dendron Gaspianum, Lepidostrobus Richardsoni, L. Matthewi, Psilo- phyton princeps, P. robustum, Selaginites formosus, Cordaites Robbii, C. angustifolius, Cyclopteris Jacksoni. Fossit Fiona oF THE CARBONIFEROUS SystEM.—The Carboni- ferous period is one of the most important as regards fossil plants. The vegetable forms are numerous and uniform throughout the whole system, whether exhibited in the Old or the New World. The im- portant substance called Coal owes its origin to the plants of this epoch. It has been subjected to great pressure, and hence the appearance of the plants has been much altered. It is difficult to give a definition of Coal. The varieties of it are numerous. There is a gradual transition from Anthracite to Household and Parrot Coal, and the limit between Coal and what is called bituminous shale is by no means distinct. Coal may be said to be chemically-altered vegetable matter interstratified with the rocks, and capable of being used as fuel. On examining thin sections of coal under the micro- scope, we can detect vegetable tissues both of a cellular and vascular nature. In Wigan cannel coal vegetable structure.is seen throughout the whole mass. Such is likewise the case with other cannel, parrot, and gas coals. In common household coal, also, evident traces of organic tissue have been observed. In some kinds of coal punctated woody fibre has been detected, in others scalariform tissue, as well as cells of different kinds. Sporangia are also occasionally found in the substance of coal, as. shown by Mr. Daw in that from Fordel; and some beds, like the Better bed of Bradford, are composed almost entirely of these sporangia, embedded in their shed microspores, as has been recently shown by Huxley. The structure of coal in different beds, and in different parts of the same bed, seems to vary according’ to the nature of the plants by which it has been formed, as well as to metamorphism. Hence the different varieties of coal which are worked. The occurrence of punctated tissue indicates the presence of Coniferze in the coal bed, while scalariform vessels point to Ferns and their allied forms, such as Sigillaria and Lepidodendron. The ana- 730 FOSSIL FLORA OF THE CARBONIFEROUS SYSTEM. tomical structure of the stems of these plants may have some effect on the microscopic characters of the coal produced from them. ‘In some cannel coals structure resembling that of acrogens has been observed. A brownish-yellow substance is occasionally present, which seems to yield abundance of carburetted hydrogen gas when exposed : to heat. Unger enumerates 683 plants of the Coal-measures, Schimper men- tions 566, while Brongniart notices 500. Of the last number there are 6 Thallogens, 346 Acrogens, 135 Gymnosperms, and 13 doubtful plants. This appears to be a very scanty vegetation, as far as regards the number of species. It is only equal to about 1-20th of the num- ber of species now growing on the surface of the soil of Europe. Although, however, the number of species was small, yet it is pro- bable that the individuals of a species were numerous. The propor- tion of Ferns was very large. There were between 200 and 300 enumerated, The following are some of the Cryptogamous and Phane- rogamous genera belonging to the flora of the Carboniferous period :— Cyclopteris, Neuropteris, Odontopteris, Sphenopteris, Hymenophyl- lites, Alethopteris, Pecopteris, Coniopteris, Cladophlebis, Senftenber- gia, Lonchopteris, Glossopteris, Caulopteris, Lepidodendron (Lepido- strobus, Lepidophyllum), Lyginodendron (Dictyoxylon), Knorria, Ulodendron, Halonia, Psaronius, Sigillaria and Stigmaria, Cala- mites, Asterophyllites, Sphenophyllum, Néggerathia, Peuce, Dadoxy- lon, Araucarioxylon, Trigonocarpus. Ferns are the carboniferous fossil group which presents the most obvious and recognisable relationship to an order of the present day. While cellular plants and those with lax tissues lose their characters by the maceration to which they were subjected before fossilisation took place, ferns are more durable, and retain their structure. It is rare, however, to find the stalk of the frond completely preserved down to its base. It is also rare to find fructification present. In this respect, fossil Ferns resemble Tree-ferns of the present day, the fronds of which rarely exhibit fructification. Hooker states that of two or three kinds of New Zealand Tree-ferns, not one specimen in a thousand bears a single fertile frond, though all abound in barren ones. Only one surface of the fossil Fern-frond is exposed, and that gener- ally the least important in a botanical point of view. Fructification is sometimes evidently seen, as figured by Corda in Senftenbergia. Mr. Carruthers has recently detected the separate sporangia of Ferns full of spores in calcareous nodules in coal. These have the elastic ring characteristic of the Polypodiacex, and in their size, form, and method of attachment, they are allied to the group Hymenophyllex. The absence of fructification presents a great obstacle to the determi- nation of fossil Ferns. Circinate vernation, so common in modern Ferns, is rarely seen in the fossil species, and we do not in general FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. 731 meet with rhizomes, Characters taken from the venation and forms of the fronds are not always to be depended upon, if we are to judge from the Ferns of the present day. There is a great similarity between the carboniferous Ferns of Britain and America. In the English Coal-measures the species are 140. The preponderance of Ferns over flowering plants is seen at the present day in many tropical islands, such as St. Helena and the Society group, as well as in extra-tropical islands, as New Zealand. In the latter, Hooker picked336 kinds in an area of a few acres; they gave a luxuriant aspect to the vegetation, which presented scarcely twelve flowering plants and trees besides. An equal area in the neighbourhood of. Sidney (in about the same latitude) would have yielded upwards of 100 flowering plants, and only two or three Ferns. This Acrogenous flora, then, seems to favour the idea of a humid as well as mild and equable climate at the period of the coal formation—the vegetation being that ‘of islands in the midst of a vast ocean. Among the Ferns found in the clays, ironstones, and sandstones of the Carboniferous period, we shall give the characters of some by way of illustration. Sphenopteris («gjv, a wedge, and wrégsc, a fern) has a bi-tripinnatifid frond, pinnz narrowed at the base (cuneate), not adherent to the rachis, lobed, veins generally arranged as if they radi- Fig. 908. ated from the base (fig. 908). In Pecopteris (réxw, I comb), the frond is pinnatifid or bi-tripinnatifid (often pectinate), pinnze adnate Fig. 908. Sphenopteris Henninghausii, a‘fern of the Carboniferous system. Fig. 909. Pecopteris aquilina, another fern. Fig. 910. Neuropteris Loshii, another fern. 732 FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. to the rachis, sometimes confluent, a strong primary vein reaching the apex, the secondary veins being nearly straight, simple, or forked, rarely pinnate, sori rounded at the end of the secondary veins (fig. 909). In Neuropteris (vedgov, a nerve) the frond is pinnate or bi- pinnate, pinnz sub-cordate at the base, distinct from the rachis, strong primary vein vanishing towards the apex, secondary veins oblique, arched, repeatedly dichotomous (fig. 910). Lonchopteris has its frond multi-pinnatifid, and the leaflets more or less united together at {the base; midrib is distinct, and the veins are reticulated. Cyclopteris has simple orbicular leaves, undivided or lobed at the margin, the veins radiating from the base, with no midrib. Schizo- pteris resembles the last, but the frond is deeply divided into numerous unequal segments, which are usually lobed and taper-pointed. Caulo- pteris and Psaronius are names given to the stems of Tree-ferns found in the coal-fields, Tree-ferns appear to have existed in Britain during the deposit of the coal strata, and to have occupied an important place in the flora. The stems of these ferns are included under the genus Caulopteris. The fronds have not been found attached ; but it is probable that some of the fronds found in the Coal-measures have been connected with these stems. Prof. W. C. Williamson says that the number of fossil ferns has been needlessly multiplied, and he includes the entire series of four petioles and stems found in the Coal- measures under the name Rachiopteris. These petioles belong, no Fig. 911. Pecopteris, Sphenopteris, etc. The way in which the vascular bundles in the four stems are arranged, are, he says, represented by the letters H, T, V, and X. Asa general rule the secondary bundles are given Fig. 911. Lepidodendron crenatum, with the scars of the leaves onits stem. It belongs to a family of plants apparently intermediate between Conifers and Lycopodiacee. Fig. 912. Lepidodendron elegans, with its dichotomous trunk and linear acute leaves. FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. 733 off from that part of the primary one which happens to be nearest the secondary rachis to be supplied. Fossil plants, allied to Lycopodiums, also occur in the Coal- measures, Brongniart believes they are more abundant in the ancient beds than in the superior beds of the greater part of the coal for- mation. These have been included under the genera Lycopodites, Selaginites, and Lepidodendron (Aewic, a scale, and dévégov, a tree), (figs. 911,912). The last mentioned appear to occupy an intermedi- ate place between Coniferze and Lycopodiacee. Their leaves are arranged in the same manner as some of the Conifers, and their scars are similar. , Their branches bifurcate like Lycopodiaces. | They oecur in the form of dichotomous | trunks, 20 to 45 feet high, with linear or / lanceolate leaves (fig. 912), like those of some species of Lycopodium and Eutassa. Schimper enumerates 59 species of Lepido- dendron, all arborescent and carboniferous. | The stem consists of a thin cuticle, a double cellular zone, a vascular cylinder, and a pith. Le The vascular cylinder consists of polygonal tubes marked with lines, while the pith is composed of fusiform cells. The stems are marked with rhomboid and orbicular scale- like scars (fig. 911). Their conelike fruit | occurs in a fossil form, called Lepidostrobus (fig. 913). It consists of a central axis |. . : bearing scales, which cover sporangia. In \:; Sy the interior of these there are spores con- eae sisting of 3 or 4 angular sporules. There pana isasingle sporangium on each scale, and all the sporangia are filled with microspores. In Lepidostrobus we do not meet with two kinds of spores. In Triplosporites, another Lycopodiaceous plant, there is a single sporangium on each scale. The sporangia in the upper portion of the cone contain microspores, while those at the lower part have macro- spores, in the same way as occurs in the genus Selaginella (p. 278). Flemingites is another fruit of the same kind. It is a cone with a double series of small sporangia on each scale. The sporangia of Flemingites occur sometimes abundantly in coal (Trans. Roy. Soc. Edin., xxi. 187). It is conjectured that in some cases the mass of the coal is formed by sporangia of plants allied to Ferns and Lycopods. The various forms of Lepidophyllum are said to be the leaves of Fig. 913. Lepidostrobus ornatus, after Lindley and Hutton, from the Bensham coal- seam of the Jarrow colliery, showing central axis with leaflets. It is the fructification of a Lepidodendron, 734. FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. Lepidodendrons. Professor W. C. Williamson, who has examined with great care the fossil carboniferous Flora, has detected in many of the plants an apparent exogenous mode of formation in the stem. According to him the stem of a Lepidodendron consists of a central medullary axis containing scalariform vessels and cells. It is sur- rounded by a narrow ring of a similar nature, but arranged in vertical lamine radiating from within outwards. The lamine are separated by cells, arranged like the medullary rays of an Exogen. From the outer cylinder vessels go to the leaves. Outside the woody zone there is a cortical portion, formed by parenchymatous and prosenchymatous cells. The whole is covered by an epidermis, con- sisting of a cellular layer, then a bast layer, and finally a superficial cellular layer. The outer epidermal covering is often removed, and is sometimes converted into coal. The stem increases in a more or less exogenous manner, while the cortical portion retains all the characters of Lepidodendroid plants. Williamson thinks that there is an evident transition from the vascular Cryptogams to the Gymnospermous Exo- gens, and that they cannot be separated. There are some difficulties in deciding on the exogenous development of a fossil stem. To deter- mine this properly, we require to demonstrate the existence of Cambium cells, and it is not easy to do so in fossilised plants. Care is also re- quired in pronouncing on the mode of development, seeing that the thick stems of cellular plants, such as seaweeds, sometimes exhibit concentric circles, and the same thing occurs in the succulent roots of some annual and biennial plants. The beautiful microscopical pre- parations made by Professor Williamson certainly show in many instances marked zones with rays. Full details of his researches are given in the Transactions of the Royal Society of London, illustrated by excellent plates. The slender terminal branches of Lepidodendron are known under the name of Lycopodites. Ulodendron (#Ay, wood, and 6dévdgo, tree) is a genus nearly allied to Lepidodendrons. Hugh Miller states that Ulodendron minus, found in ferruginous shale in the Water of Leith, near Colinton, exhibits beautiful sculptured scars, ranged rectilinearly along the stem. The surface is covered with small, sharply-relieved obovate scales, most of them furnished with an apparent midrib, and with their edges slightly turned up. The circular or oval scars of this genus are probably impressions made by a rectilinear range-of aerial roots placed on either side. When decorticated, the stem is mottled over with minute dottings, arranged in a quincuncial manner, and its oval scars are devoid of the ordinary sculpturings. Bothrodendron (8éégos, a pit or depression) is a decor- ticated condition of Ulodendron. Halonia appears also to be a species of Lepidodendron. The scars of Ulodendron, and the tubercles of Halonia, are probably the remains of special organs, such as cones. FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. 735 Stigmaria (oriywo, a mark or impression) is a fossil genus, the species of which abound in the Coal-measures. They occur generally in the bed called the Underclay. Stigmaria ficoides (fig. 914) is the common species. It sends forth grooved and pitted branches, which divide dichotomously, and extend 20 to 30 feet. Slender processes are given off, which appear to have been hollow (fig. 914), These processes (called fistular roots) form an entangled mass traversing the Fig. 914. "Fig. 915. argillaceous lower bed in every direction. In Stigmarias three tissues are met with,—vascular tissue forming the inner part of the cylinder, ligneous forming the wood, and cellular tissue forming a broad cortical zone, as well as the central portion or pith, Stigmaria is apparently a thick rhizome, having a large medulla, surrounded by a cylinder of scalariform vessels, and with a mass of cortical parenchyma sur- rounding the whole. Rootlets proceed from the pits on the sides of the rhizome, each containing a small bundle of scalariform vessels having its origin in the vascular cylinder. In the structure of its stem it agrees, according to some, with Cycads, and with certain fleshy Euphorbiacee and Cactacee. According to Williamson, Stig- maria has a pith surrounded by a thick woody zone, containing two distinct sets of primary and secondary medullary rays, the former going direct to the bark. In what are called decorticated stems of the Lepidodendroid plants, the more central axial portion (medulla, wood, and thin layers of inner bark) have disappeared through decay ; the bast Fig. 914. Stigmaria ficoides; a branch giving off fistular leaves, which traverse the underclay in all directions. Fig, 915. Sigillaria pachyderma ; showing fluting of the stem, and the scars of the leaves. 736 FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. layer of the bark has arrested the destruction of the entire cylinder, and formed the mould into which inorganic materials have been intro- duced. In Stigmaria, however, the woody cylinder is usually pre- served, probably owing to its more tenacious character. Some think that the stores of fossil fuel in England and America are mainly due to the presence of this plant. Stigmaria ficoides has been shown to be the rhizome and roots of a Sigillaria. Specimens of the latter have been discovered standing erect, and connected with Stigmarias. Stig- maria ficoides abounds in the underclay of a coal seam, sending out numerous roots from its tubercles, and pushing up its aerial stem in the form of a fluted Sigillaria. Sigillaria (sigillum, a seal) is another plant which appears to have aided in the formation of coal. It occurs in the form of compressed stems, attaining a height of 40 to 50 feet, and a breadth of 5 feet. The stems are fiuted longitudinally, and marked at regular intervals by single or double scars (hence their name), the remains of the leaf insertions (fig. 815). Some suppose Sigillarias to be allied to Tree- ferns, others to Conifer. Brongniart says they resemble Zamia integrifolia, and appear to predominate in the middle and superior beds of the coal formations. Some consider them as intermediate between Ferns and Cycads. Their foliage has not been accurately determined, some conjecturing that it consisted of Neuropteris, others of long linear leaves, called Cyperites. They have a medullary sheath in the shape of apparently isolated bundles, and vessels interme- diate between true spiral and scalariform. The stem of Sigillaria is fluted in a longitudinal manner, like a doric column, and has a suc- cession of single scars, which indicate the points of insertion of the leaves. When the outer part of the stem separates like bark, it is found that the markings presented by the inner surface differ from those seen externally. This has sometimes given rise to the erroneous supposition that they belong to different genera. King says, that if in imagination we delineate a channelled stem of any height between 12 and 100 feet, crowned with a pendent fern-like foliage, furnished with wide-spreading thickly-fibrilled roots, and growing in some densely-wooded swamp of an ancient Mississippi, we will then have formed a tolerably close restoration of a Sigillaria vegetating in its true habitat. The fructification consists of small sporangia, like that of Flemingites, borne on the bases of the leaves, and this indicates an acrogenous plant allied to Lycopods. Calamites (xcdr.amos, a reed), a reed-like coal fossil plant, occurs in the form of jointed fragments, originally cylindrical and hollow, but now crushed and flattened (fig. 916). The stem is ribbed and furrowed (fig. 917), articulated and septate. It consisted of a cortical portion now converted into coal, of a medulla, at first solid and then fistular, surrounded by a woody cylinder of scalariform vessels. The FOSSIL PLANTS OF THE CARBONIFEROUS System. ‘737 medulla penetrated this cylinder by a series of wedges, which were continued to the outer portion of the stem by their cellular laminz. The appendicular organs (leaves) were produced in whorls. Williamson considers the structure of the medullary and ligneous zones as resembling that of the stem of an exogen of the first year. On making a longi- Fig. 916. Fig. 917. tudinal tangential section of the stem, the woody zones show alter- nating parallel bands of vascular and cellular tissue. The bark con- sists of a thin layer of parenchyma. It is smooth outside, and does not present ridges or furrows. The ligneous cylinder of Calamite, as it increases in size and age, exhibits less and less of the Calamitean peculiarities seen in young stems; the external part becoming unsul- cated. In a Calamitean plant, called by Williamson Calamopitus, canals pass from the medullary cavity, horizontally to the bark, below the nodes (infranodal). Calamites give off subterranean branches from rhizomes as well as slender appendages from the aerial stem, arranged in verticils at the nodes. Williamson puts Calamites in his order Calamitacez, allied to Equisetacez, but differing in having cryptogamic reproduction connected with an exogenous de- velopment of the stem. Schimper considers Calamites as having an analogy with Equisetum in their fructification. He regards them as fossil Equisetacee. Annularia and Sphenophyllum are considered as establishing a passage from the Equisetaceze to the Lycopodiacez. Some gigantic fossil Equiseta had a diameter of more than 12 centi- metres, and a height of 8 to 10 metres. The branches, which adorned the higher part of them in the form of a crown, are simple, have at their extremity a spike of the size of a pigeon’s egg, and are organised exactly like the spikes of living Equiseta. There is also a resem- blance between them as regards their rhizomes. Dr. W. R. M‘Nab has examined the Equisetum stem, and contrasted it with that of Cala- mite, and he has come to the following conclusions :—That the stem of Equisetums differs but little in construction from that of Calamites : Fig. 916. Calamites Suckovii, composed of jointed striated fragments having a bark. Fig. 917. Calamites canneformis, giving off roots. 3B 738 FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. that in both Equisetums and Calamites the fibro-vascular bundles are but poorly developed: that the mass of tissue (woody wedges" of Williamson) forming the most important part of the stem consists of the small fibro-vascular bundles, with the addition of a large quantity of thickened parenchyma and prosenchyma (sclerenchyma of Met- tenius): that the sclerenchyma is part of the cortical tissues, and not a portion of the fibro-vascular bundles: that there is no evidence of any growth having taken place in the fibro-vascular bundles com- parable to that observed in Dicotyledons ; but that if the stems of Calamites increased in diameter it was by additions to the cortical tissues, and not to those of the fibro-vascular bundles: that the pointed ends of the Calamite stem (indicating that the embryonic parts did not enlarge) lead to the conclusion that circumferential growth did not take place, but that the stem, when it attained its maximum diameter close to the base, remained cylindrical. f = SS Po We 4 eS | x TEE pert ott Fig. 919. 4 In Spitzbergen, in rocks of the Carboniferous epoch, there have been found Calamites radiatus, Lepidodendron Veltheimianum, Sigil- laria distans, Stigmaria ficoides, and ferns apparently the same as those found in the Carboniferous epoch in Europe. Some species, as Sigillaria Malmgreni, 8. Canneggianna, and Lepidodendron Wilkii, seem to be peculiar to Bear Island. In the family Calamitaceee we have the genera Equisetites and Calamites. Some also place in this family the genera Asterophyllites, Sphenophyllum (fig. 918), Annularia (fig. 919), and Volkmannia, Annularia may be a link between Equisetacese and Ferns, and Sphe- nophyllum a link between Lycopodiacee and Ferns. Williamson Fig, 918..Sphenophyllum dentatum, one of the dubious forms of the Carboniferous system, perhaps allied to Salisburya Fig. 919. Annularia brevifolia, a coal plant of doubtful affinity, placed by some among the Calamitacez. FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. 739 considers Asterophyllites as having a general affinity with Lycopo- diacez and not with Equisetacee. He finds its parallel in the present flora in Psilotum triquetrum. It is also allied to the fossil plant called Sphenophyllum (fig. 918), Asterophyllites Dawsoni, formerly called Volkmannia Dawsoni, has a peculiar triquetrous vascular axis. True Exogenous trees exist in the Coal-fields both of England and Scotland, as at Lennel Braes and Allan Bank, in Berwickshire, High- Heworth, Fellon, Gateshead, and Wide-open, near Newcastle-upon- Tyne, and in quarries to the west of Durham; also in Craigleith quarry, near Edinburgh, and in the quarry at Granton. In the latter localities they lie diagonally athwart the strata, at an angle of about 30°, with the thicker and heavier part of their trunks below, like snags in the Mississippi. From their direction we infer that they have been drifted by a stream which has flowed from nearly north- east to south-west. At Granton one of the specimens exhibited roots. In other places the specimens are portions of stems, one of them 6 feet in diameter by 61 feet in length, and another 4 feet in diameter by 70 feet in length. These Exogenous trees are Gymnosperms, hav- ing woody tissue like that of Conifersee, Wesee under the microscope punctated woody tissue, the rows of disks being usually two, three, or more, and alternating (figs. 906, 907). They seem to be allied in these respects to Araucaria and Eutassa of the present flora. Dadoxy- lon or Pinites (Araucarioxylon) Withami is one of the species found in Craigleith quarry ; the concentric layers of the wood are obsolete ; there are 2, 3, or 4 rows of discs on the wood, and 2-4 rows of small cells in the medullary rays. Along with it there have also been found Dadoxylon medullare, with inconspicuous zones, 2, 3, and 4 rows of discs, and 2-5 series of rows of cells in the rays. Pissadendron an- tiquum (Pitus antiqua), having 4-5 series of cells in the medullary rays, and P. primevum (Pitus primzva), with 10-15 series of cells in the medullary rays, occur at Tweedmill and Lennel Braes in Berwickshire. Sir Robert Christison states—“ Seven fossils, all apparently belong- ing to the Pine tribe, and either to the same species, or to two closely allied to one another, have been uncovered since 1826 in the sandstone of Craigleith quarry. Six are stems of great trees, and one is a longi- tudinally split section of a large branch, or possibly of another stem. Por- tions of all seven have been traced as still preserved in Collections, and have been subjected more or less to examination. Of one, the greatest of all, about 36 continuous feet, from 12 to 14 feet in girth, have been removed in large fragments to the British Museum, and will be pieced and erected there. Another, found in 1830, is now partly in the Botanic Garden, and has been supplemented by other portions from the Museum of Science and Art, so as to make a nearly perfect fossil stem 30 feet in length. A third, nearly 9 feet in girth, has been sliced 740 FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. and polished, to show its structure on the great scale, and will be exhibited in the British Museum, the Edinburgh Museum, and the Edinburgh Botanic Garden. “The composition of all these great fossils is substantially the same. The great mass of each consists of carbonate of lime, carbonate of magnesia, carbonate of protoxide of iron, and free carbon, the pro- portions varying in different parts of the same fossil. The iron-car- bonate and charcoal vary most in their amount. The charcoal, which is left after the action of diluted acids, sometimes without any other insoluble residuum, seems to form three per cent of the mass, unless when collected, as it often is, in cavities. This charcoal contains only about 34 per cent of incombustible ash. “The surface of the fossils is covered with a shining coat of very bituminous caking coal, which, on the principal part of the stem, varies from only a 20th to a 10th of an inch in thickness, but at the lower end of that now at the British Museum, it increases to two inches and a half. This coaly covering contains only 4, 3, 2, and sometimes only 1:1 per cent of mineral matter, which is not the same as the fossilising matter of the included wood, but is chiefly siliceous in nature, being at least insoluble in acids. The crust is not altered bark, for bark could not fail to undergo, in part at least, fossilisation by the material which has fossilised the wood. Moreover, the coaly crust is found round fragments and on broken points where bark could never have existed. “The rock of the quarry is a very pure quartzy sandstone, hard, tough, and quite free from earthy carbonates or iron. But for some feet around the fossils, and also here and there throughout the quarry, where there is no fossil near, the rock has quite a different appearance, has a higher density, is more sharp-edged, much tougher, and harder to pulverise, and becomes yellow under exposure to the air. These changes are owing to the siliceous particles of the sandstone being bound together by carbonate of lime, carbonate of magnesia, and car- bonate of protoxide of iron, forming together from 10 to 38 per cent of the rock, and bearing much the same relation in proportion to each other as in the mineral material of the fossils,—consequently derived from the same fluid which fossilised them. ‘“‘Thus the interesting fact is presented of these great trees and the rock in which they are embedded having been both similarly mineralised, so to speak, by the same fossilising fluid, while there is between them a thin uniform coating of bituminous coal, which has refused admission to any of the fossilising agents. After rejecting various theories to account for this exemption, the only one which stands the test of facts is, that a part of the process of fossilisation consists in a slow process, analogous in its results to the destructive distillation of wood, the result of which is charcoal left behind, FOSSIL PLANTS OF THE CARBONIFEROUS SYSTEM. 741 and bitumen gradually forced outwards, and collected on the exterior surface. “The charcoal which remains in the stems renders their minute internal structure singularly distinct when a thin transparent slice is placed under the microscope. Longitudinal woody bundles, transverse medullary rays, crowded cells of the longitudinal fibres cut crosswise, are all seen most characteristically ; and in one specimen two inches in breadth the boundaries and whole structure of five annual layers of wood are displayed characteristically, even to the naked eye. On the polished surface of one of the great stems, too, the eye can easily trace many annual rings for long distances.” Sternbergia is considered by Williamson as a Dadoxylon, with a discoid pith, like that seen now-a-days in the Walnut, Jasmine, and Cecropia peltata, as well as in some species of Euphorbia and in some Conifers. Sternbergia approximata is named by him Dadoxylon approximatum. Hooker has shown from the structure of Trigono- carpus, a not uncommon fruit, that it is a coniferous fruit, nearly allied to Salisburya. Néggerathia, and a few other plants, such as Flabellaria and Artisia, are referred by Brongniart to Cycadacez. Flabellaria borassifolia, according to Peach, has leaves like Yucca. Noggerathia has pinnate leaves, cuneiform leaflets, sometimes fan- shaped ; the veins arise from the base of the leaflets, are equal in size, ¥Z ee =x Pi oe Ss a FEN eee Fig. 920. Fig. 921. Fig. 920. Cardiocarpum Lindleyi,’collected by C. W. Peach, near Falkirk, a peculiar fossil ‘of the Coal-measures, supposed to be the fruit of Antholithes. Fig. 921. Pothocites Grantoni. a, Spike natural size, 6, Portion of the spike magnified. vc, Perianth 4-cleft. magnified, 742 STATE OF THE GLOBE AT THE COAL EPOCH. and either remain simple or bifurcate, the neuration or venation being similar to that of some Zamias. A fossil plant called Antholites has been found in the coal-mea- sures. It appears to be a spike of flowers, having a calyx and linear petals. Mr. Peach has recently found that the fruit called Cardio- carpum is the produce of this plant (fig. 920). It may possibly be a Monocotyledon. Mr. Peach has also found a peculiar fossil fern near Edinburgh, which presents the characters of the genus Staphylopteris of Lesquereux. In the bituminous shale at Granton, near Edinburgh, Dr. Robert Paterson discovered in 1840 a peculiar fossil plant, which he called Pothocites Grantoni (fig. 921). It is a spike covered by parallel rows of flowers, each apparently with a 4-cleft perianth. It was sup- posed to be allied to Potamogeton or Pothos, more probably to the latter. In that case it must be referred to the natural order Aracez. Pothocites has been recently found by Mr. Etheridge near West Calder, and by Mr. Bennie at Corstorphine, near Edinburgh. Lygino- dendron (Adyioc, wicker-work) is a peculiar coal fossil discovered by the Rev. Mr. Landsborough in Ayrshire, and described by Mr. Gourlie. Its impression consists of rounded narrow twigs, which cross each other like the parts of an osier basket. Lyginodendron (called also Dictyoxylon by Williamson) is probably allied to Lycopods. It has a stem composed of pith, wood, and bark. The parenchymatous pith is surrounded by an irregular vascular cylinder, which breaks up into bundles, separated by medullary parenchyma. Before this, however, the true ligneous zone appeared as a narrow vascular ring, with radiat- ing vertical lamina, separated from each other by large cellular rays. A bark exists in the circumference formed of two cellular layers, and a third composed partly of parenchyma and partly of prosenchyma. Two species are described by Williamson, Lyginodendron Oldhamia - and D. Grievii. It may be remarked, in general, that the Carboniferous flora is uniform, or nearly so, in all parts of the globe where carboniferous. fossils have been obtained—viz. the whole of western, northern, and eastern Europe, North America, from Alabama to Melville Island, various districts of Asia, Eastern Australia, and Van Diemen’s Land, and probably the Asiatic Islands. As fossils in the coal formation consist principally of ferns and their - allies, conjectures have been made as to the climate of the globe at that epoch. Ferns of the present day thrive best in a moist insular climate, and many of them occur in tropical climates. Hence Brongniart conjec- tures that at the coal epoch the surface of the earth consisted of a series of islands in the midst of a vast ocean, and that the temperature was higher generally than that of the present day. In the forests of these islands lofty Lepidodendrons would occur, with their delicate and STATE OF THE GLOBE AT THE COAL EPOCH. 743 feathery fronds; Sigillarias, with their fluted stems and enormous matted roots; Calamites, with their singular branches; Tree-ferns and Coniferous plants, resembling the Norfolk Island Pine, and towering a hundred feet above the rest of the forest. He also thinks that the immense deposits of carbon at that epoch warrant the con- clusion that the air contained a large amount of carbonic acid. These conclusions are, of course, mere hypotheses. In regard to the.tem- perature, it may be remarked that there is no evidence, from the nature of the flora, of a marked increase of temperature at the coal epoch. In New Zealand, which is in a latitude the same as that of a great part of Europe, a very large proportion of the vegetation con- sists of Acrogenous plants. Ferns and their allies, in that country, cover immense districts, replacing the grasses of other countries, and giving a marked character to all the open land. Some of the ferns attain a height of 30 or 40 feet, and occur in groups. Hemitelia capensis, a Tree-fern found at the Cape, was also seen by Gardner, at an elevation of 6000 feet, on the Organ mountains, thus showing a capability of enduring a great range of climate, and. warning us against hasty conclusions on the subject of the temperature of the world at the coal epoch. Dr. Hooker thinks that the prevalence of ferns may be regarded as a probable evidence of the paucity of other plants, and the general poverty of the whole flora which characterised the formation. He is led to these conclusions from observing the mode in which the ferns in Van Diemen’s Land and New Zealand monopolise the soil, choking plants of a larger growth on the one hand, and admitting no under- growth of smaller species on the other. In New Zealand he has col- lected 36 kinds of ferns on an area not exceeding a few acres ; they. gave a most luxuriant aspect to the vegetation, which presented scarcely a dozen flowering plants and trees besides. Some have supposed that the plants of the coal-fields have been drifted into basins, others that they grew in the spots where they are now found. Beaumont thinks that all the plants which are now converted into coal grew in swampy islands, covered with a luxuriant vegetation, which accumulated in the manner of peat-bogs ; that those islands having sunk beneath the ocean, were there covered with sand, clay, and shells, till they again became dry land, and that this opera- tion was repeated in the formation of each bed of coal. The occur- rence of stems of trees in an erect state (fig. 922) appeared to him to confirm the view that the trees were in situ. Ansted says, that although many trees are found in the Coal-measures in an erect or highly-inclined position, there is no reason for believing that they grew on the spot where they are met with, He rather thinks that they have been caught or stopped in their passage down a rapid stream, and, like the snags in some of the great’ American rivers, have been 744 FLORA OF THE PERMIAN EPOCH. detained till the lower portion was firmly embedded in the rapidly forming sandstone. The embedding of stems in strata of sandstone is similar to what Gardner saw near the mouth of the Rio San Fran- cisco, where coco-nut trees were found with their stems immersed to the depth of 50 feet or more in the embankment of sand which stretches along the shore. Phillips remarks, that the condition of AN I | tH i Liu ai ale i Te oe lei ie a A Paci miei i { i Ney nN a ee Te ai 4 ‘ Fig. 922. the plants which compose the coal, the general absence of roots, the fragmentary state of the stems and branches, the dispersed condition of the separable organs, all confirm the conclusion that the plants have been swept down from the land on which they grew by watery currents, often repeated, and deposited in basins and large estuaries of the sea, or, perhaps rarely, in lakes of fresh water. Fuora oF THE Psruian Epocu.—The nature of the vegetation during the Permian period, which is associated with the Carboniferous, under the reign of Acrogens, has not been positively determined. Brongniart has enumerated the fossils in three different localities, which he refers doubtfully to this period. 1. The flora of the bituminous slates of Thuringia, composed of Algz, Ferns, and Conifere. 2. Flora of the Permian sandstones of Russia, comprehending Ferns, Equisetacex, Lycopodiacer, and Noég- gerathiz. 3. Flora of the slaty schists of Lodéve, composed of Ferns, Fig. 922. Vertical stems of fossil trees, Calamites chiefly, found in the Coal-measures of Treuil, near Saint Etienne. FLORA OF THE SECONDARY PERIOD. 745 Asterophyllites, and Conifer. The genera of Ferns here met with are also found in the Car- boniferous epoch; the Gymnosperms are chiefly species of Walchia (figs. 923, 924) and Noégeger- & athia (the latter is sup- posed. by Schimper to be a Cycad) ; Lepidodendron elongatum, Calamites gi- gas, and Annularia flori- bunda, are also species of this period. Goeppert has given an account of the plants of the Permian formation. Among other plants he enumerates the following : — Equisetites contractus, Calamites Suc- kowi, OC. leioderma, Astero- phyllites equisetiformis, A. elatior, Huttonia truncata, H. equiseti- formis, many species of Psaronius one of the filicoid plants, Hymeno- phyllites complanatus, Sphenopteris crassinervia, Sagenopteris teni- folia, Neuropteris imbricata, and many other species of these genera ; several species of Odontopteris, Callipteris, Cyclopteris, Dioonopteris, Cyatheites, Alethopteris, Néggerathia, Cordaites, Anthodiopsis, Dicty- othalamus, Calamodendron, Arthropitys ; besides ‘species of Sigillaria, Stigmaria, and Lepidodendron. Various fruits are also mentioned, under the names of Rhabdocarpus, Cardiocarpus, Acanthocarpus, Trigonocarpus, and Lepidostrobus. II. —FLORA OF THE SECONDARY OR MESOZOIC PERIOD. BRonGNiIART’s REIGN oF GYMNOSPERMS, In the Carboniferous period the Acrogenous Cryptogams were found to predominate, while the Gymnospermous Dicotyledons were less numerous. In this reign, on the other hand, the Acrogens are less numerous, and the Gymnosperms almost equal them in number, and ordinarily surpass them in frequency. Figs. 923, 924. Walchia piniformis Sternb., a common species in the Permian rocks of Europe, Fig. 923, Plant with leaves and fructification. Fig. 924. Fructification, natural size. 746 REIGN OF THE GYMNOSPERMS. The reign of the Gymnospermous Dicotyledons is divided into two periods: the first, in which the Coniferee predominate, while the Cycadacez scarcely appear; the second, in which the latter family preponderates as regards the number of species, and the frequency and variety of generic forms. Cycadacez (figs. 925, 926) occupied a more important place in the ancient than in the present vegetable world. They extend more or less from the Triassic formation up to the ‘L, we Fig. 925. Fig. 926. Tertiary. They are rare in the Grésbigarré or lower strata of the Triassic system. They attain their maximum in the Lias and Oolite, in the latter of which 60 species have been enumerated, and they disappear in the Tertiary formations. Schimper thinks that Trigonocarpum (15 species), Rhabdocarpum (24 species), Cardiocarpum (21 species), Carpolithes (9 species), and Cycadinocarpus (6 species), are all fruits of Cycadez. Many supposed fossil Cycads are probably Conifers. It is important to notice that in an existing Cycad called Stangeria paradoxa the vernation of the leaf-divisions is involute and inflexed, and the veins of the pinnz rise from a true midrib and fork, characters which are more commonly met with in Ferns. In Brongniart’s Vosgesian period, the Grésbigarré, or the Red Sandstones and Conglomerates of the Triassic system, there is a change Fig. 925. Cycas revoluta, one of the species of Cycas of the present flora of the globe, with its scale-like stem and pinnate fronds, Fig. 926. Encephalartos (Zamia) pungens, one of the Cycadacev at present existing on the globe. FLORA OF THE TRIAS AND LIAS EPOCH, 747 in the flora, Sigillarias and Lepidodendrons disappear, and in their place we meet with Gym- nosperms, belonging to the genera Voltzia, Haidingera, . Zamites (fig. 927), Ctenis, ARthophyllum, and Schizo- neura (fig. 928). Species of Neuropteris, Pecopteris, and other acrogenous coal genera are still found, along with species of Anomopteris and Crematopteris, peculiar Fern- forms, which are not found in | later formations. Stems of arborescent Ferns are more frequent than in the next period. In the Lias the essential characters of the flora are the predominance of Cycadacee, ; in the form of species of Cycadites, Otozamites, Zamites, Ctenis, Pterophyllum (figs. 929, 930), and Nilssonia, and the existence ~ Fig, 928. among the Ferns of many genera with reticulated vernation, such as Camptopteris and Thaumatopteris, some of which began to appear at Fig. 927. Zamites. Leaf of a fossil Cycad. Fig 928. Schizoneura heterophylla, one of the fossil conifere of the Triassic system. 748 FLORA OF THE OOLITIC EPOCH. the Keupric epoch. Coniferous genera, as Brachyphyllum, Taxodites, Palissya, and Peuce, are found. y In the Oolitic epoch the flora consists of numerous Cycadaceze and Coniferee, some of them having peculiar forms. Schimper enumerates Fig. 932. Fig. 929. Paleozamia pectinata (Zamia pectinata of Brongniart, and of Lindley and Hutton), a pinnati-partite leaf of a fossil Cycad. Fig. 930. Pterophyllum Pleiningerii, leaf of a fossil Cycadaceous plant. Fig. 931. Brachyphyllumgmammillare, a Coniferous genus of the Oolitic System, Yorkshire, Fig. 932. Equisetum columnare, a fossil species of the Oolite of Yorkshire. FLORA OF: THE OOLITIC EPOCH. 749 96 Ferns, 61 Cycads, and 14 Conifers. The distinctive characters of this flora are, the rarity of Ferns with reticulated venation, which are so numerous in the Lias, the frequency of the Cycadaceous genera Otozamites and Zamites, which are most analogous to those now existing ; of a‘remarkable group presenting very anomalous structure in their organs of reproduction, to which Mr. Carruthers has given the name of Williamsonia, and the diminution of Ctenis, Ptero- phyllum, and Nilssonia, genera far removed from the living kinds ; and lastly, the ‘greater frequency of the coniferous genera, Brachy- phyllum (fig. 931), and Thuites, which are much more rare in the Lias. In the Scottish Oolite at Helmsdale Miller has detected about 60 species of plants, including Cycadacee and Conifer, with detached cones, and Fern forms resembling Scolopendrium. He also discovered a species of Equisetum (fig. 932), and a Calamite which is a connect- ing link between the Oolitic and Carboniferous epochs. There is an absence of true coal-fields in the secondary formations generally ; but in some of the Oolitic series, as in the lower Oolite at Brora, in Sutherlandshire, and the Kimmeridge clay of the upper Oolite, near Weymouth, there are considerable deposits of carbon- aceous matter, but the vegetable remains are only in the state of im- perfect lignite ; some suppose that the Brora coal was formed chiefly by Calamites columnaris. In the sandstones and shales of the Oolitic series, especially in the lower Oolite of the north of England, as at Whitby and Scarborough, as well as in Stonesfield slate, the Portland Crag of the middle, and the Portland beds of the upper Oolite, nume- Fig. 933. Fig, 934, rous fossil plants are found. Peuce Lindleyana is one of the Conifers of the lower Oolite. Beania is a Cycadaceous fossil from the Oolite of Yorkshire. Araucarites spherocarpus is found in the inferior Oolite. The upper Oolite at Portland contains an interesting bed, about a foot in thickness, of a dark brown substance, containing much earthy Fig. 933. The Dirt-bed of the island of Portland, containing stumps of fossil Cycadacee in anerect position, Fig. 934. Cycadoidea megalophylla (Mantellia nidiformis of Brongniart), a subglobose depressed trunk, with a concave apex, and with the remains of the petioles disposed in a spiral manner, the markings being transversely elliptical, It is found in the Oolite of the Island of Portland, in a silicified state. 750 FLORA OF THE CRETACEOUS EPOCH. lignite. This is the Dirt-bed, made up of black loam, which, at some far distant period, was penetrated by the roots of trees, fragments of whose stems are now found fossilised around it. These consist of an assemblage of silicified stumps or stools of large trees, standing from 1-3 feet from the mould. Most of them are erect, some slightly in- clined, and the roots remain attached to the earth in which they grew (fig. 933). They appear to resemble Cycadacew. One of these is Mantellia nidiformis (fig. 934). Carpolithes conica and Bucklandia are fruits found in the Oolite. Some look upon them as fruits of palms. The flora of the Wealden epoch is characterised in the south of England by the abundance of the fern called Lonchopteris Mantellii, and in Germany by the predominance of the Conifer denominated Abietites Linkii, and the presence of Araucarites Pippingfordiensis, as well as by numerous Cycadacez, such as species of Cycadites, Zamites, Pterophyllum, Mantellia, Bucklandia, and a remarkable genus having a fleshy fruit, and related to the ordinary Cycadacee’ as Taxus is to the other Coniferee, which has been described under the name of Bennettites. In the Wealden at Brook Point, Isle of Wight, Cycads have been detected allied to Encephalartos. Their fruit has been de- scribed by Carruthers as Cycadeostrobus. There are several species. Mantell has found 40 or 50 fossil cones in the Wealden of England. The remains are those of land plants. The Wealden fresh-water for- mation terminates the reign of Gymnosperms. JIL—FLORA OF THE TERTIARY OR CAINOZOIC PERIOD. (Including the Cretaceous Epoch.) Broneniarr’s REIGN or ANGIOSPERMS. This reign is characterised by the appearance of Angiospermous Dicotyledons, plants which constitute more than three-fourths of the present vegetable productions of the globe, and which appear to have acquired the predominance from the commencement of the Tertiary epoch. These plants, however, appear even at the beginning of the Cretaceous period. In this reign, therefore, Brongniart includes the upper secondary period, or the Cretaceous system, and all the Tertiary period. The Cretaceous may be considered as a sort of transition period between the reign of Gymnosperms and Angiosperms. The Creraczovus (chalk) period is characterised by the Gymno- spermous almost equalling the Angiospermous Dicotyledons, and by the existence of a considerable number of Cycadacez, which do not appear in the Tertiary period. The genus Credneria is one of the character- FLORA OF THE TERTIARY PERIOD. 751 istic forms. In this period we find Alge represented by Cystoseirites, Confervites, Sargassites, and Chondrites ; Ferns by peculiar species of Pecopteris and Protopteris; Naiadacee by Zosterites; Palms, by Flabellaria and Palmacites; Cyacadacee, by Cycadites, Zamites, Microzamia, Fittonia, and Bennettites ; Conifer, by Brachyphllum, Widdringtonites, Cryptomeria, Abietites, Pinites, Cunninghamites, Dammarites, Araucarites; and Angiospermous Dicotyledons, by Comptonites, Alnites, Carpinites, Salicites, Acerites, Juglandites, and Credneria. In the Gault of Folkestone a cone allied to that of Sequoia gigantea has been detected. Carruthers thinks that the con- iferous vegetation of the highlands of the upper Cretaceous system had a facies similar to that now existing in the mountains in the west of North America, between the 30th and 40th parallel of latitude. With the chalk, Ansted says, we close, as it were, one great volume of the history of animated creation. Everything up to this point belongs to the past ; everything on this side of it may be ranked among indica- tions of the present. New forms, new types of organisation, corre- sponding to different habits and altered circumstances, now replace those which have passed away. The conditions under which animals and vegetables lived were changed, and a new epoch commenced upon the earth. At the base of the Tertiary period, there is a Fucoidean epoch, characterised by deposits rich in Alge of a very peculiar form, belonging to the genera Chondrites and Munsteria. No land plants have been found mingled with these marine species. The TERTIARY series of Rocks are well seen in the south of Europe, Asia, and America. In Britain the tertiary deposits are met with in the London clay, in Hampshire and the Isle of Wight, the Suffolk and Norfolk Crag, and in the Till of the Clyde. The London clay contains numerous fruits belonging to many hundred species of plants. The first tertiary land of which we have knowledge seems to have been richly clothed with plants. The strata are, generally speaking, rich in fossils. The stems and leaves appear to be-those of Dicotyledons, little differ- ing from the plants of the present day (figs. 935-939). In the brown coal of this series, the structure of the wood is evident, and distinctly exogenous (figs. 935-937), and there are often associated with it leaves of Poplars, Elms (fig. 938), Oaks, Beeches, Maples, Hazels, Birches, and other forest trees. The fossil plants of the Isle of Sheppey have been examined by Bowerbank, and have led to the determination of several hundred species of plants, all of them extinct, and all resem- bling those of warmer climates :—fruits of Nipadites (Pandanocarpum), a fossil plant, allied to Nipa, one of the Pandanacee ; Hightea, a five- seeded fruit, probably Malvaceous; also the fruit of a Proteaceous plant, and of species allied to. Canna, Cucumber, and the Leguminose and Conifers of the present day. To some of them the names of Cupanoides, Wetherellia, Cucumites, and Mimosites, have been given. 752 FLORA OF THE TERTIARY PERIOD. In some of the tertiary formations there occur pieces of wood, which present the structure of that of Pepper-plants and of Palms (figs. 940, 941), and there are also leaves which have the flabelliform appearance rin i uc INNA Saeesssnltifi Fig. 938. Fig. 939. of Palm leaves, included under the name of Palmacites (fig. 942). Specimens allied to Chara are also found, with their fructification denominated Gyrogonites. The Tertiary period is characterised by the abundance of Angio- Figs. 935-937. Structure of ordinary Dicotyledonous stems, to illustrate the appearances presented by some tertiary fossil woods. Fig. 935. Portion of a Dicotyledonous (Exo- genous) stem cut transversely. Natural size. Fig. 936. Section of the same magnified, to show the occurrence of large porous vessels. The ordinary Dicotyledons differ in this respect from Conifer. . Fig. 937. Longitudinal section of the same in the line a B, per- pendicular to the medullary plates, showing woody tissue and large pitted vessel, and the rays appearing here and there among the woody tissue. Fig. 938. Leaf of fossil Elm of the middle Tertiary epoch. Fig. 939. Leaf of Comptonia acutiloba, an Amentiferous plant of the same epoch. FLORA OF THE TERTIARY PERIOD. 753 spermous Dicotyledons and of Monocotyledons, more especially of Palms. By this it is distinguished from the more ancient periods. Angiosperms at this period greatly exceed Gymnosperms. Cycadaceze are yery rare, if not completely wanting, in the European Tertiary strata, and the Conifer belong to genera of the temperate regions, Fig. 941. In the lower Tertiaries, Carruthers has found a fossil Osmunda, In the Tertiary beds some of the Pines are found. The Cupressinez occur in the Tertiary beds only. Taxodiese are represented by Sequoia in the Cretaceous and Eocene shale. Peuce australis of Van Diemen’s Land and P. Pritchardi of Ireland are Tertiary plants. Isoetes is mentioned by Schimper as a Tertiary genus. Although the vegetation throughout the whole of the Tertiary period presents pretty uniform characters, still there are notable differences in the generic and specific forms, and in the predominance of certain orders at dif- ferent epochs. In the Eocene formation, the fossil fruits of the Isle of Sheppey increase the number of Phanerogamous plants, only a small proportion of which have as yet -been described. This is an exceptional locality, and is perhaps an example of the effects of cur- ‘rents in conveying exotic plants from remote climates. The Eocene epoch in general is characterised by the predomi- nance of Algz and marine Naiadacez, such as Caulinites and Zosterites ; Fig. 940. Section of a recent Palm stem, to show its structure. The dark dots marking vascular bundles in the midst of cellular tissue. Fig. 941. A portion of the same magni- fied, to show the vascular bundles. Fig. 942. Palmacites Lamanonis (Flabellaria litigiosa). Leaf of a Monocotyledon resembling a Palm. 3¢ 754 FLORA OF THE EOCENE AND MIOCENE EPOCHS. by numerous Conifers, the greater part resembling existing genera among the Cupressinexw, and appearing in the form of Juniperites, Thuites, Cupressites, Callitrites, Frenelites, and Solenostrobus ; by the existence of a number of extra-European forms, especially of fruits, such as Nipadites, Leguminosites, Cucumites, and Hightea ; and by the presence of some large species of Palm belonging to the genera. Flabellaria and Palmacites. Unger says that the Eocene flora has resembled in many respects that of the present Australian vegetation. He gives the following genera as occurring at the Eocene epoch :— Araucaria, Podocarpus, Libocedrus, Callitris, Casuarina, Pterocarpus, Drepanocarpus, Centrolobium, Dalbergia, Cassia, Ceesalpinea, Bauhinia, Copaifera, Entada, Acacia, Mimosa, Inga. Amber is considered to be the produce of many Conifers of this epoch, such as Peuce succini- fera or Pinites succinifera, and Pinus Rinkianus. It occurs in East Prussia in great quantity, and it is said that many pieces of fossil wood occur there, which, when moderately heated, give out a decided smell of amber. Connected with these beds are found cones belonging to Pinites sylvestrina and P. Pumilio, Miocene species nearly allied to the living Pinus; others to Pinites Thomasianus and P. brachy- lepis. Goeppert contrasts the present flora of Germany and that of the Amber epoch as follows :— German Flora. Amber Flora. Cryptogamez ‘ 6800 60 Phanerogamee . 3454 102 Cupuliferze . 12 10 Ericaceze 23 24 In the Lower Eocene of Herne Bay, Carruthers found Osmundites Bowkeri. Berkeley has detected in amber fossil fungi, which he has named Penicillium curtipes, Brachycladium Thomasinum, and Strepto- thrix spiralis. Some Characez are also met with, as Chara medica- ginula and C. prisca, with a fossil called Gyrogonites, the nucule or the fructification of these plants. Carpolithes ovatus, a minute seed- vessel, occurs in the Eocene beds of Lewisham. It is probably allied to the sporangium of a fern. Another small fruit, of a similar nature, called Folliculites minutulus,. occurs in the Bovey Tracey coal, which belongs to the Tertiary beds. The most striking characters of the MiocENE epoch consist in the mixture of exotic forms of warm regions with those of temperate cli- mates, Unger says that it resembles that of the southern part of North America. Thus we meet with Palms, such as species of Fla- bellaria and Pheenicites, a kind of Bamboo called Bambusium sepul- tum, Lauracez, as Daphnogene and Laurus ; Combretacex, as Getonia and Terminalia ; Leguminosz, as Phaseolites, Desmodophyllum, Doli- FLORA OF THE MIOCENE EPOCH. 755 chites, Erythrina, Bauhinia, Mimosites, and Acacia—all plants having their living representatives in warm climates; Echitonium, Plumiera, and other Apocynacee of equatorial regions, and Steinhauera, a Cin- chonaceous genus; mingled with species of Acer (Maple), Ulmus (Elm), (fig. 936), Rhamnus (Buckthorn), and Amentiferous forms, such as Comptonia (fig. 938), Myrica, Betula (Birch), Alnus (Alder), Quercus (Oak), Fagus (Beech), Carpinus (Hornbean), all belonging to temperate and cold climates. The statements as to the occurrence of Pinus sylvestris and Betula alba among the Miocene fossils have not been founded on complete data. It is by no means easy, even in the present day, to distinguish fragments of dried specimens of Pinus Pumilio from those of P. sylvestris, and from a great many other Pines. The difficulty is still greater in fossils, There are a very small number of plants belonging to orders with gamopetalous corol- las. As connected with the Miocene epoch, we may notice the leaf- beds found at Ardtun, in the island of Mull, by the Duke of Argyll. Above and below these beds basalt occurs, and there are peculiar tuff- beds alternating with the leafy deposits. These tuff-beds are either of volcanic origin, or are a conglomerate stratified deposit, altered in a metamorphic manner. The beds are associated with chalk and flints. The leaves are those of plants allied to the Yew, Rhamnus, Maple, Plane, and Alder, along with the fronds of a peculiar Fern, and the stems of an Equisetum. The genera are Taxites or Taxodites, Rham- nites, Platanites, Alnites, Filicites, and Equisetum. In the leaf-beds at Bournemouth Mr. Wanklyn detected several ferns. One is called by him Mertensites, and shows distinct venation and fructification. Fos- silised wood was found in the Arctic Regions by Captain M‘Clure. At the. N.W. of Banks’ Land he found trees with trunks 1 foot 7 inches in diameter. The Arctic fossil flora (Miocene), according to Heer, amounts to 162 species: Cryptogamia, 18 species, of which 9 are large ferns ; Phanerogamia, Conifer, 31; Monocotyledons, 14 ; Dicotyledons, 99. Among the Conifere are— Pinus M‘Clurii, Sequoia Langsdorfii, Sternbergii, and Couttsie, Taxodium dubium, Glyptostrobus Euro- “ peus, Thuiopsis Europea. Among leafy trees are—Fagus Deuca- lionis, Quercus Olafsoni, Platanus aceroides, willows, beeches, Acer, Otopteryx, tulip-tree, walnuts, Magnolia Inglefieldi, Prunus Scottii, Tilia Malmgreni, Corylus M‘Quarrii, Alnus Kefersteinii, Daphnogene Kannii probably one of the Lauracez ; and among Proteacese ? Mac- Clintockia and Hakea. In Greenland are found species of Rhamnus, Paliurus, Cornus, Ilex, Cratzgus, Andromeda, Myrica, Ivy, and Vine. From the flora of Spitzbergen, in the Miocene epoch, we may conclude that under 79° N. lat. the mean temperature of the year was 41° Fahr., while at the same epoch that of Switzerland was 69°°8 Fahr., judging from the analogy of floras. It appears that for each degree of 756 FLORA OF THE PLIOCENE EPOCH. latitude the mean temperature has fallen 0°9 F. From this it fol- lows that at Spitzbergen, at.78° N. lat., the mean temperature was 41°-9 Fahr ; in Greenland, at 70°, it was 49°] Fahr. ; and in Iceland and on the Mackenzie, in lat. 65°, it was 52°7 Fahr. At the Miocene epoch the temperature was much more uniform, and the mean heat diminished much more gradually in proportion as the pole was approached. ‘The isothermal line of 32° Fahr. fell upon the Pole, while now it is situated under 58° N. In speaking of the Polar flora of former epochs, Heer says, “‘ Every plant executes a slow and continuous migration. These migrations, the starting-point of which is the distant past, are recorded in the rocks ; and the interweaving of the carpets of flowers which adorn our present creation retraces them for us in its turn, For the vegetation of the present day is closely connected with that of preceding-epochs; and throughout all these vegetable creations reigns one thought, which not only reveals itself around us by thousands upon thousands of images, but strikes us everywhere in the icy regions of the extreme north. Organic nature may become impoverished there, and even disappear when a cold mantle of ice extends over the whole earth ; but where the flowers die the stones speak, and relate the marvels of creation ; they tell us that even in the most distant countries, and in. the remotest parts, nature was governed by the same laws and the same harmony as immediately around us.” The flora of the PLIocENE epoch has a great analogy to that of the temperate regions of Europe, North America, and Japan.’ We meet with Coniferee, Amentiferze, Rosacee, Leguminose, Rhamnacer, Aceraceze, Aquifoliaceze, Ericacee, and many other orders. There is a small number of Dicotyledons with gamopetalous corollas. The twenty species with such corollas recognised by Brongniart are referred to the Hypogynous Gamopetalous group of Exogens, which in the general organisation of the flowers approach nearest to Dialypetale. In this flora there is the predominance of Dicotyledons in number and variety ; there are few Monocotyledons and no Palms. No species appear to be identical, at least with the plants which now grow in Europe. Thus the flora of Europe, even at the most recent geological epoch of the Tertiary period, was very different from the European flora of the present day. Taking the natural orders, which have at least four represent- atives, Raulin gives the following statement as to the Tertiary flora of Central Europe. The Eocene flora of Europe is composed of 128 species, of which 115 belong to Algze, Characes, Pandanacee, Palme, Naiadacee, Malvacee, Sapindacer, Proteacer, Papilionacee, and Cupressinez. The Miocene flora has 112 species, of which 69 be- long to Alge, Palme, Naiadaces, Apocynaces, Aceracee, Lauracee, Papilionacez, Platanacew, Quercinee, Myricacee, and Abietinex. . FLORA OF THE TERTIARY PERIOD IN EUROPE. 757 The Pliocene flora has 258 species, of which 226 belong to Algw, Fungi, Musci, Filices, Palme, Ericacee, Aquifoliacez, Aceracer, Ulmaceex, Rhamnacee, Papilionacer, Juglandacee, Salicacese, Quer- cine, Betulacex, Taxacez, Cupressine, and Abietinese. The Eocene species are included in genera which belong at the present day to inter-tropical regions, comprising in them India and the Asiatic islands of Australia. Some are peculiar to the Mediterranean region. The aquatic plants, which form almost one-third of the flora, belong to genera now peculiar to the temperate regions of Europe and of North America, or occurring everywhere. The Miocene species belong to genera, of which several are found in India, tropical America, and the other inter-tropical regions, but which for the most part inhabit the sub-tropical and temperate regions, including the United States. Some of the genera are peculiar to the temperate regions. The aquatic genera, poor in species, occur everywhere, or else solely in the temper- ate regions, The Pliocene species belong to genera which almost all inhabit the temperate regions either of the old continent or of the United States. A few only are of genera existing in India, Japan, and the north of Africa, These various floras, which present succes- sively the character of those of inter-tropical, “sub- tropical, and tem- perate regions, seem to indicate that central Europe has, since the commencement of the Tertiary period, been subjected, during the suc- cession of time, to the influence of these three different temperatures. It would appear, then, Raulin remarks, that the climate of Europe has during the Tertiary period gradually become more temperate. This may proceed either from a displacement of the earth’s axis, or from the gradual cooling of the earth, or from a different proportion of land and water. Brown coal occurs in the upper Tertiary beds, and in it vegetable structure is easily seen under the microscope. Goeppert, on examin- ing the brown coal deposits of northern Germany and the Rhine, finds that Coniferze predominate in a remarkable degree. Among 300 specimens of bituminous wood collected in the Silesian brown coal deposits alone, only a very few other kinds of Exogenous wood occur. This seems remarkable, inasmuch as in the clays of the brown coal formation in many other places leaves of deciduous Dicotyledonous trees have been found ; and yet the stems on which we may suppose them to have grown are wanting. The leaves have been floated away from the place where they grew by a current of water, which was not powerful enough to transport the stems. The coniferous plants of these brown coal deposits belong to Taxineze and Cupressinez chiefly. Among the plants are Pinites protolarix and Taxites Ayckii. Many Conifer exhibit highly compressed very narrow annual rings, such as occur in those of northern latitudes. Goeppert has described a trunk, or rather the lower end of a trunk, of Pinites protolarix, dis- 758 GENERAL CONCLUSIONS. covered in 1849 in the brown coal of Laasan in Silesia. It was found in a nearly perpendicular position, and measured more than 32 feet in circumference. Sixteen vast roots ran out almost at right angles from the base of the trunk, of which about four feet stood up perfect in form, but stripped of bark. Unfortunately the interior of the stem was almost entirely filled with structureless brown coal, so that only two cross sections could be obtained from the outer parts, one sixteen inches, the other three feet six inches broad. In the first section Goeppert counted 700, in the second 1300 rings of wood, so that for the half- diameter of 54 feet, at least 2200 rings must have existed. As there is every reason to believe that the rings were formed in earlier ages just as the annual zones are now, this tree would be from 2200 to 2500 years old. Exogenous stems in lignite are often of great size and age. In a trunk near Bonn, Néggerath counted 792 annual rings. In the turf bogs of the Somme, at Yseux near Abbeville, a trunk of an Oak-tree has been found above 14 feet in diameter. We have thus seen that the vegetation of the globe is represented by numerous distinct floras connected with the different periods of its history, and that the farther back we go the more are the plants different from those of the present day. There can be no doubt that there have been successive deposits of stratified rocks, and successive creations of living beings. We see that animals and plants have gone through their different phases of existence, and that their remains in all stages of growth and decay have been embedded in rocks super- imposed upon each other in regular succession. It is impossible to conceive that these were the result of changes produced within the limits of a few days. Considering the depth of stratification, and the condition and nature of the living beings found in the strata at various depths, we must conclude (unless our senses are mocked by the pheno- mena presented to our view) that vast periods have elapsed since the Creator in the beginning created the heavens and the earth. How far it may be possible in the future to correlate the history of the earth inscribed on its rocky tablets and deciphered by the geologist, and that short narrative which forms the introduction to the Sacred Volume, it is difficult to say. At present there are no satisfactory materials for such a correlation ; but one thing is certain, that both Revelation and Geology testify with one voice to the work of a Divine Creator. When we find animals and plants of forms unknown at the pre- sent day, in all conditions as regards development, we read a lesson in regard to the history of the earth’s former state as conclusive as that which is derived from the Nineveh relics (independent of Revelation) in regard to the history of the human race. There is no want of har- mony between Scripture and geology. The Word and the Works of ee WORKS ON FOSSIL BOTANY. 759 God must be in unison, and the more we truly study both, the more they will be found to be in accordance. Any apparent want of corre- spondence proceeds either from imperfect interpretation of Scripture or from incomplete knowledge of science. The changes in the globe have all preceded man’s appearance on the scene. He is the charac- teristic of the present epoch, and he knows by Revelation that the world is to undergo a further transformation, when the elements shall melt with fervent heat, and when all the present state of things shall be dissolved, ere the ushering in of a new earth, wherein righteousness is to dwell, ° On the subject of Fossil Botany the following works may be con- sulted :— Argyll, Duke of, on Tertiary Leaf Beds in the Isle of Mull, Journ. Geol. Soc., May 1851. Balfour, on Vegetable Organisms in Coal, Trans. R.S.E., vol. xxi. ; Paleontological Botany, 1872. Bennett, on the Structure of Torbane Hill Mineral and other Coals, Trans. R. Soc. Ed., vol. xxi. p. 173. Binney, E. W., on Cala- mites and Calamodendron, Paleontographical Society’s Memoirs, 1868. Bower- bank, Fossils of the London Clay. Brongniart, Histoire des Végétaux Fossiles, 1828-1844 ; Observations sur la Structure interieure du Sigillaria, etc., in Archives du Museum, i. 405; Exposition Chronologique des Periodes de Végétation, in Ann. des Sc. Nat., 3d series, Bot. xi. 285. Carruthers, on Gymnospermatous Fruits from the Secondary Rocks of Britain, Journ. Bot., Jan. 1867; on the Structure of the Stems of the Arborescent Lycopodiacee of the Céal Measures, Month. Microse. Journ. i. 177; on The Cryptogamic Forests of the Coal Period, April 1869 ; on the Structure and Affinities of Sigillaria and Allied Genera, Quart. Journ. Geol. Soc., Aug. 1869; on some Fossil Coniferous Fruits, Geol. Mag., vols. iii. vi. ; On Beania, a new genus of Cycadean Fruit, from the Yorkshire Oolites, Geol. Mag., vol. vi. ; on Plant-remains from the Brazilian Coal-beds, with Remarks on the genus Flemingites, Geol. Mag., vol. vi. ; on the Fossil Cycada- ceous Stems from the Secondary Rocks of Britain, Linn. Trans., xxvi. 675. Christison on Fossil Trees of Craigleith, Proc. R.S.E., 1873. Corda, Beitrige zur Flora der Vorwelt, Prag. 1845. Cotta, Dendrolithen. Dawson, on Vegetable Structures in Coal, Quarterly Journal Geological Society, 1860; on the Pre-Carboniferous Flora of New Brunswick and Eastern Canada, Canadian Naturalist, May 1861; on the Flora of the Devonian Period in North-Eastern America, Quart. Journ. Geol. Soc., Nov. 1862 ; on an Erect Sigillaria and a Car- polite from Nova Scotia, Quart. Journ. Geol. Soc. Lond. ; on Calamites, Ann. Nat. Hist., 4th ser., vol. iv. 272; on the Varieties and Mode of Preservation of the Fossils known as Sternbergie, Canadian Naturalist ; Acadian Geology, 1868. Ettinghausen, Beitrige zur Flora der Vorwelt in Abhandlungen der Geolog. Reich- sanstalt, Vienna, 1851. Forbes, on the Vegetable Remains from Ardtun Head, Quart. Journ. Geol. Soc. Lond., vol. vii. Giebel, Paleontologie. Goeppert, Die Gattungen der Fossilen Pflanzen, Bonn, 1841; Monographie des Fossilen Coni- feren, 1850; Systema Filicum Fossilium, Nova Acta, xvii. ; Ueber die Fossilen Cycadeen, Breslau, 1844; Erliuterung der Steinkohlen-Formation ; Die Fossile Flora der Permischen Formation, in Paleontographica, von Meyer, Cassel, 1864 ; Beitrage zur Kenntniss Fossilen Cycadeen, Breslau. Grand d’Eury, on Calamites and Asterophyllites, Ann. Nat. Hist., ser. 4, vol. iv. 124. Harkness, on Coal, Edin. Phil. Jour., July 1854. Heer, Flore Fossile des Regions Polaires, 1869, transl. Ann. Nat. Hist., 4th ser., p. 61. Hooker, on some Minute Seed-vessels (Carpolithes Ovulum, Brongniart) from the Eocene beds of Lewisham, Proceed. 760 WORKS ON FOSSIL BOTANY. Geol. Soc., 1855 ; Vegetation of the Carboniferous Period, in Mem. of Geol. Sur- vey, ii. ; on a New Species of Volkmannia, Quart. Journ. Geol. Soc, Lond., May 1854. King, on Sigillaria, etc., in Edin. New Phil. Journal, xxxvi. Lesquereux, on the Coal-Measures of America, Silliman’s Journal, 1863. Report of the Trial as to the substance called Torbane Mineral or Torbanite. Lindley and Hutton, Fossil Flora. Our Coalfields, by a Traveller under ground. Lowry, Table of the Characteristic Fossils of Different Formations. Nicholson, on the Occurrence of Plants in the Skiddaw Slates, Geol. Mag., vol. vi. Paterson, Description of Pothocites Grantoni, Trans. Bot. Soc. Edin., vol. i. Penny Cyclopedia, vol. vii., Coal Plants. Pictet, Manual of Paleontology. Quekett, on the Minute Structure of Torbane Hill Mineral, Journ. Microsc. Sc., 1854. Raulin, Flore de l'Europe pendant la Période Tertiaire, in Ann. des Sc. Nat., 3d ser., x. 193. Redfern, on the Nature of the Torbane Hill and other Varieties of Coal, Brit. Assoc. Liver- pool, 1854. Saporta, Etudes sur la Végétation du Sud-Est de la France 4 YEpoque Tertiaire, Annales des Sciences Naturelles, ser. 4, tome xvi. 309, xvii. 191, xix. 5; ser. 5, tome iii. 5, iv. 5. Schimper, Traité de Paléontologie Végé- tale, 3 vols. 8vo, with folio plates. Tate, on the Fossil Flora of the Mountain Limestone Formation of the Eastern Borders, in connection with the Natural His- tory of Coal (in Johnston’s Eastern Borders), Unger, Genera Plantarum Fos- silium ; Chloris Protogea ; Le Monde Primitive (a work which contains picturesque views of the supposed state of the earth at different geological epochs). William- son, on the Structure and Affinities of the Plants hitherto known as Sternbergia, Sept. 1851 ; on a New Form of Calamitean Strobilus, from the Lancashire Coal Measures, Mem. Lit. Phil. Soc. Manchester, vol. iv., 3d series ; on the Structure of the Woody Zone of an Undescribed Form of Calamite, Mem. Lit. Phil. Soc. Manchester, vols. iv. and viii., 83d series; on Zamia gigas (Williamsonia gigas), Linn. Trans. xxvi. 663 ; on the Organisation of Fossil Plants of the Coal-Measures, Phil. Trans. R.8.L., vols. 161-164. Witham, on the Structure of Fossil Vege- tables. M‘Nab, Dr., on the Structure of Calamites,.Ed. Bot. Soc. Trans., vol. xi. p. 487. Yates, on Zamia gigas, Proceed. Yorkshire Phil. Soc., Aspril1847. Besides geological treatises such as those of Ansted, Beudant, Jukes, Lyell, and others. APPENDIX. —+—. I.—On Tue Us oF THE Microscore IN BoTanicaL ResEARCHES. Tur Microscope is a most important instrument in education, and it is essential for the due understanding of the structure and physiology of plants. The study of the microscopical structure of organised bodies is termed Histology (iorés, a web or tissue, and Adyos, discourse). Dr. Carpenter remarks :—“‘ The universe which the microscope brings under our ken seems as unbounded in its limit as that whose remotest depths the telescope still vainly attempts to fathom. Wonders as great are disclosed in a speck of whose minuteness the mind can scarcely form any distinct conception, as in the most mysterious of those nebule whose incalculable distance baffles our hopes of attaining a more minute knowledge of their constitution. And the general doctrines to which the labours of microscopists are manifestly tending, in regard to the laws of organisation and the nature of vital action, seem fully deserving to take rank in comprehensiveness and import- ance with the highest principles yet attained in physical or chemical science. It is by pursuing, by the aid which the microscope alone can afford to his visual power, the history of the organic germ, from the simple and homogeneous form which seems common to every kind of living being —either to that complex and most heterogeneous organism which is the mortal tenement of man’s immortal spirit, or only to that humble Protophyte or Protozoon, which lives, and grows, and multiplies, without showing any essential advance upon its em- bryonic type, that the physiologist is led to the grandest conception of the unity and all-comprehensive nature of that creative design, of which the development of every individual organism, from the lowest to the highest, is a separate exemplification, at once perfect in itself and harmonious with every other.” The microscope (mmeés, small, and oxoréw, T see) is an instrument for enabling the eye to see distinctly objects which are placed at a very short distance from it, or to see minute objects that would other- wise be invisible. It has been used with great success in the examination of vegetable structure. To it we are indebted fora knowledge of the various vessels and cells which enter into the com- 762 LENSES OF VARIOUS KINDS. position of the different parts of plants, of the circulation of fluids, and of ciliary movements, as well as for the facts connected with the development of the embryo. It is an instrument, however, which requires to be used cautiously ; and the conclusions drawn from it ought to be carefully weighed, more especially when the observations have been made with high magnifying powers. Lunsres.—Before proceeding to notice the construction of simple and compound microscopes, it will be advantageous to notice the different kinds of lenses used, and the sources of error which require to be guarded against in their preparation. The chief forms of lenses used are the double-convex (fig. 943, 4), with two convex faces ; plano- : conver (fig. 943, 3), with one face flat and the other convex; double-concave (fig. 943, 2), with two concave faces ; and plano-concave (fig. 943, 1), with one flat and one concave face. Some- times, also, a meniscus (fig. 943, 5) is used, with a concave and a convex face, and a sharp edge, and a concavo-convew (fig. 943, 6), with a concave and convex surface and flat edges. Convex lenses with sharp edges cause parallel rays to converge ; while concave lenses with flat edges cause them to diverge. The lenses used in microscopes are chiefly convex—the concave lenses being employed to make certain modifica- tions in the course of the rays passing through convex lenses, whereby their performance is rendered more exact. The magnifying power of a single lens is inversely as its focal length. The principal focus is the point to which parallel rays converge after refraction. The focal distance of a double convex lens is half that of a plano-convex lens, having the same curvature. In the use of ordinary lenses there are sources of error from the form of the lens and the nature of the material of which it is made. When parallel rays fall on a double- convex or a plano-convex lens, they are brought to a focus at a certain distance from the lens; but it is found that no lens with a spherical surface can bring the rays of light to the focus at one point. Hence arises what is called spherical aberration. In this kind of aberration the rays which pass through the lens near its circumference are brought to a focus nearer to the lens than those which pass through near the centre, hence the objects at the circumference of the field of the microscope are not in focus at the same time as those in the centre. Moreover, the different coloured rays of which white light is composed are unequally refrangible, the violet rays having the greatest and the red rays having the least degree of refrangibility ; a B Fig. 943. Different kinds of lenses—1, Plano-concave. 2, Double-concave. 3, Plano- convex. 4, Double-convex. 5, Meniscus. 6, Concavo-convex. 3, 4, 5, are sharp-edged lenses, and cause convergence. 1, 2, 6, are flat-edged, and cause divergence. SIMPLE AND COMPOUND MICROSCOPES, 763 leng therefore breaks up a ray of white light into its constituent colours, so that a colourless object appears coloured. This is termed chromatic (seduce, colour) aberration. To remedy these defects certain combinations of glasses have been adopted, so that the light traversing one lens through the centre may pass through near the margin of another. The confusion produced by these aberrations may be greatly lessened by diminishing the pencil of light ; for instance, by employing a stop or diaphragm, which lessens the aperture of the lens and cuts off the peripheral rays. In lenses of low power, such as are used in the simple dissecting microscope, these aberrations do not cause much confusion. It is only when high powers are required that these aberrations must be done away with. The invention of Wollaston’s doublet with two lenses, and Holland’s triplet with three, was with the view of diminishing, as far as possible, these aberrations. They were aplanatic (« privative, rAavéw, I wander), i.e. they remedied spherical aberration, but coloured images were still produced. Their lenses were constructed of the same kind of material; and it was found that in order that lenses might present the object uncoloured, or be what is called achromatic (a, privative, and ypauc, colour), it was necessary to use two glasses of different refractive power. Achromatic lenses, or such as are nearly free from chromatic aberration, are constructed by placing together glasses of different dispersive powers, and of |\j different forms. The usual achromatic lens consists of [iM a double-convex lens, made of plate or crown glass, and ~ _ a plano-concave, made of flint-glass (fig. 944), fitted accurately to it, and cemented by Canada balsam. Microscopes are of two kinds+Simple and compound. By the Simple Microscope objects are viewed through a single lens, or through two or three lenses placed together, so as to form doublets or triplets. The glass is arranged so that it can be brought over the object, and adjusted, by means of a rack and pinion, or by some other contrivance, to its exact focal distance—the object, when opaque, being seen by light thrown from above, and when transparent, by light transmitted from below. This instrument, when used with single lenses or doublets, is the best for ordinary botanical investigations, more especi- ally for dissections. The combination of three lenses approaches too near the object to be easily used. A very high power may be obtained by doublets formed of plano-convex glasses, or by means of the lenses termed Coddington’s or periscopic, consisting of two hemispherical lenses, cemented together by their plane faces, having a stop between them, or rather having a groove in the whole sphere filled with opaque matter. The chief objections to the simple microscope are Fig. 944. u, An achromatic and aplanatic lens, consisting of a double-convex lens of plate-glass, and a plano-concave of flint-glass. b, Section of the plano-concave lens. 764 SIMPLE MICROSCOPE. the fatigue attendant on long-continued investigations, and the small field of view. In the simple microscope, glasses of the following focal lengths may be employed—viz., 14 inch, 2, 4, 4; and, if very minute objects are to be examined, of 1-1 0th, 1-30th, or 1-40th ofan inch. For examining minute plants, such as Diatomaces and Desmidi, during an excursion, it is useful to have a simple microscope similar to that represented in fig. 945. It consists of a Wollaston’s doublet, fixed in a round plano-concave brass disc (fig. 945, 1, a), 1 Fig. 945. 2 attached to a small brass handle (fig. 945, 1, 6). For ordinary botanical purposes a lens magnifying 65 to 70 diameters is enough ; but the lenses may be procured with a power of 150 to 220 diameters. On the plane side of this brass disc there is a ring of silver (fig. 945, 1, ¢), in which a thin piece of glass is fixed, also supported by a brass handle, which acts as a spring, so as to keep the two rings in contact. Fig. 945 represents Dr. Gairdner’s portable simple’ microscope. In 1 there is given a front view of the instrument, showing the posterior silver ring, c, enclosing a piece of thin glass, separated and turned aside from the disc, a, containing the doublet, to which the eye of the observer is applied. 2 exhibits a lateral view of the instrument, with the screw, d,sby means of which the handles are separated or approximated, so as to bring the object into focus. COMPOUND MICROSCOPE. 765 In the handle of the first-mentioned disc there is a screw (fig. 945, 2, d), which passes through it, and by the motion of which the two handles can be separated or allowed to come close to each other. By this means an exact focal distance can be obtained. A drop of fluid containing Diatoms, or any minute object, is placed on the outside of the thin glass in the silver ring, and it is then covered by a similar piece of thin glass, which adheres by means of the fluid. The object being brought into focus, as in fig. 945, 2, the observer can distinguish the characters of the microscopic plant, so as to determine whether it is necessary to take specimens home for more careful examination by the compound microscope. In the Compound microscope there are two sets of lenses—the one called the object-glass or objective, the other the eye-piece or ocular. The first receives the rays from the object, and bringing them to new foci, forms an image, which the second treats as an original object, and mag~- nifies it just as the single microscope magnified the object itself. The image is inverted, but this may be remedied by making the rays pass through another set of lenses in the tube of the microscope, called an erector. In the construction of the object-glasses, great care is taken to render them achromatic. Those made by the most eminent Lon- don makers consist of two or three compound lenses, which cannot be used separately, but are fixed together in a tube. In the case of high powers, the object-glasses are also provided with an adjustment for the thickness of the glass covering the object to be viewed. This ad- justment makes up for the refraction caused by the passage of light through thin glass of different thickness, and is accomplished by altering the distance between the outer and middle pairs of lenses in the object-glass. This adaptation is especially necessary in the case of a glass with a large angle of aperture. The eye-piece, also, must be so formed as to be free from error. That used is called Huyghens’, and consists of two plano-convex lenses with their plane sides towards the eye, and placed at a distance apart equal to half the sum of their focal lengths, with a diaphragm inserted midway between the lenses. In this eye-piece, the lens next the eye is called the eye-glass, the other the field-glass. By the Huyghenian or negative eye-piece the object is seen inverted. The Ramsden or positive eye-piece consists of two plano-convex glasses, with the convex surfaces directed towards each other ; by it objects are seen erect, and it is often used as a micrometer eye-piece, that is, for measuring objects. The eye-pieces supplied with the best microscopes are usually three, and they are so constructed, that, with each of the object-glasses, they give a certain amplification of the object, the powers being in the proportion of 1, 2, and 8, or 1, 14, and 24. In the best microscopes there is also an achromatic condenser or eclairage, through which the light reflected from the mirror passes. The amplification by means of an eye-piece 766 COMPOUND MICROSCOPE. in the compound microscope enables us to use an object-glass of a lower power than would otherwise be necessary. The compound microscope, when well constructed, gives a flat and colourless picture of the object, with clearness of definition. The observer can use it for a length of time with less fatigue than when employing the simple microscope. Weak eye-pieces and strong object-glasses are to be re- commended. The eye-piece does not add either clearness or distinctness to the object, and when it is very powerful the field of view becomes too small to take in the whole image formed by the object-glass ; for the magnitude of the field of view and the strength of the illumina- tion diminishes according to the magnifying power of the eye-piece employed. The lower powers are of use in searching for the object to be examined, which may thus be more easily found by a higher power. For the lower power a linear amplification of from 20 to 50 diameters, and for a higher power a linear amplification of from 300 to 500 diameters at most, will give a sufficiently wide range of powers. The powers are increased by a more powerful eye- piece or object-glass, or by both, or by lengthening the tube of the microscope. In examining vegetable structures, an instrument magnifying 150 to 200 diameters is usually suffi- cient ; but in some instan- ces higher powers are re- quired. Achromatic object- lenses of 14, 3, and 4 of an inch focal length are recom- mended as the most essen- tial; and two eye-pieces should be provided, one of \ about 14 and the other of 4} 24 inches in length. The instrument should have both a coarse and a fine adjustment; and it is of importance that it should : = be made to incline or to Fig. 946. stand vertical, A movable stage is also useful, and a spring-holder to fix the objects on the stage, so that the different parts of the object may be viewed without being touched by the fingers. Fig. 946. Ordinary compound microscope. COMPOUND MICROSCOPE. 767 In figure 946 a compound microscope is represented. The stand or base consists of a strong tripod, a, supporting two upright pillars, bb, between the upper parts of which an axis works. This carries the whole of the optical parts of the instrument, which can be adjusted to any inclination, horizontal, vertical, or intermediate. The stage, d e, is firmly attached to the axis, as is also the double mirror, f The triangular bar, g, has a rack on its posterior part, which is worked bya pinion, the milled heads of which are seen at h h. The body, ¢, screws firmly into the arm, j ; the achromatic object-glasses are screwed into the body atm; the Huyghenian eye-piece slides into the other end of the body. The mirror is plane on one side, and concave on the other, and is fitted with a universal movement, so as to be inclined in any desired position. The milled heads, h h, by being revolved, raise or lower the body, 7, and constitute the coarse adjustment ; the fine adjustment is effected by turning the milled head, p. The object to be examined is placed on the stage, d, and retained in the required position by the sliding piece, e. The quantity of light admitted through the instrument may be modified by the diaphragm, r, which consists Fig. 947. Hartnack’s (Oberhauser’s) student’s microscope. 768 COMPOUND MICROSCOPE. of a plate of brass with four apertures of different diameters, made to Fig. 949. revolve on a central pin or axis fixed to the bottom of the stage. Figs. 948 and 949 represent Gruby’s portable compound microscope one-half its real size. Fig. 948. The instrument in its case. Fig. 949. The instrument mounted. A full description is given by Dr. Bennett in the Edinburgh Monthly Medical Jowrnal for December 1846, COMPOUND MICROSCOPE. 769 Provision is also made for adding a polarising apparatus. In addition to the four holes mentioned as needed to admit the requisite amount of light, the diaphragm is furnished with a fifth hole, into which a Nicol’s prism may be screwed, forming the polariser ; the analyser being screwed into the upper part of an adapter previously to its being attached to the body, 7. The polariser is mounted ona double tube, so as to be capable of being evolved by turning a large milled head at the bottom. A condensing lens for illuminating opaque objects may be fitted into the hole at the corner of the stage ; it is so arranged that it can be used in any required position or angle. Among the objects often: furnished with the microscope is a plate of selenite, which, if laid under many animal and vegetable structures while being ex- amined by polarised light, will cause them to assume beautiful colours. By means of a Binocular microscope objects may be seen in relief. Very good microscopes for students are made by Smith and Beck in London, and by Nachet and Hartnack in Paris. One of the latter is shown in figure 947. The figure is one-fourth of the real size of the instrument. The body consists of a telescope tube eight inches in length, held by a split tube three inches long. It may be elevated or depressed by the hand by a cork-screw movement, and this con- stitutes the coarse adjustment. It is attached to a cross-bar and pil- lar, at the lower portion. of the latter of which there is a fine adjust- ment screw. The stage is three inches broad and two and a half inches deep, with a circular diaphragm below it. The base of this portable instrument is loaded with lead so as to give it steadiness. A similar instrument is made by Nachet, in which there is a broader stage and a broader base, as well as a means of inclining the body of the instrument. The following are the magnifying powers, in diameters linear, of Nachet’s compound achromatic microscope for students :—* OBJECTIVES OcuLars (EYE-PIEcES). (OBJECT- : GLassEs) 1 2 3 “4 70 90 140 3 190 250 400 5 280 360 600 As a portable compound microscope is sometimes wanted by a student, Dr. Bennett has given the accompanying figures of one recommended by Gruby of Paris. In fig. 948 the instrument is shown in its Case, * The price of the instrument, with all these powers, is 190 francs, exclusive of duty and carriage ; without No. 2 ocular, and No. 5 objective, it is 150 francs. 3D 770 COMPOUND MICROSCOPE. and in 949 it is mounted. The woodcuts are exactly one-half the real size, and give a good idea of the instrument, a detailed description of which is not required. In fig. 950 a representation is given of one of Smith and Beck’s microscopes for students. A is the brass stand, sup- ported firmly on three feet, and having two upright flat cheeks, to the top of which the stage-plate, d, is fixed. Into the stage-plate is screwed an upright round tube, to which is attached an open tube, g, in which the body of the instrument, fh, slides. By moving the body up and down in this tube, the coarse adjust- ment is effected, and when the instrument is brought near to the object on the stage-plate, d, a finer adjustment is made by means of the screw with the milled head, ¢, which either raises or depresses the part by which g is attached to the up-- right tube. The mirror is re- presented at 6, supported on trunnions, and capable of mo- tion upwards or downwards, so as to reflect the light on the object placed on the stage- plate ; cis the diaphragm or stop, or perforated plate attached to the stage, with the view of shutting off the extreme rays of light. The object-glass or objective is placed at the lower end of the instrument, f, and the eye-piece or ocular at the upper part, h. In fig. 951 a diagram is given to explain the mode in which the compound microscope acts. In this figure, o is the object, above which is seen the triple achromatic object-glass or objective, consisting of three achromatic lenses, which are combined in one tube ; ¢c is the eye-piece or ocular, consisting of two plano-convex lenses, one at ¢, being the eye-glass, and the other at c, the field-glass. Three rays of Fig. 950. Fig. 950. Smith and: Beck’s compound microscope for students. A, brass stand, sup- ported on three feet ; b, mirror supported on trunnions ; c, diaphragm ; d, stage-plate on which the object is placed ; e, screw with milled head for fine adjustment ; g, brass tube in which the body of the instrument is moved, so as to effect the coarse adjustinent ; f, the object-glass or objective; h, the eye-piece or ocular. Fig. 951. Diagram to show the mode in which the compound microscope acts. O, an object, with three rays of light from its centre, and three from each of its ends; ec, eye-piece, consisting of two plano-convex lenses—one at e, the eye-glass, the other at c, the field-glass ; b, diaphragm ; a, the point where an image would be formed if the rays were not made to converge by the lens ¢. MICROSCOPIC APPARATUS, 71 light are represented as proceeding from the centre of the object, and three from each end of it. These rays, if uninterrupted, would form an image of the object at a, but owing to the interposition of the field-glass c, they are refracted so as to converge and meet at b, where the diaphragm is placed to intercept all light except what is necessary for the formation of a perfect image. The image formed at b is viewed as an original object by the observer through the eye- glass e. Microscopic APPARATUS.—In measuring the size of microscopic objects, a micrometer (wineds, small, and mérgov, a measure) is em- ployed. The stage micrometer consists of a piece of glass, ruled with fine lines by means of a diamond point, at some known distance apart, such as the rcth, or rsvth, or réscth of an inch. A mode of ascer- taining the magnifying power of the compound microscope is founded on the assumption that the naked eye sees most clearly and distinctly at the distance of ten inches. If a divided scale be placed on the stage, and distinctly seen magnified through the instrument, let a rule be held at ten inches’ distance from the right eye, while the observer uses, at the same time, his left eye in looking at the other scale through the microscope, and let the rule be gently moved so that it is seen to overlap or lie by the side of the magnified picture of the other scale,—a comparison as to how many of its known divisions corre- spond with a number of those on the magnified scale will indicate the magnifying power. Upon a similar principle a pair of compasses may be substituted, whose points being placed on the stage are sepa- rated till they cover or mark off so many spaces as magnified by the instrument. If they cover one magnified space, and correspond to 2, 3, or more, known spaces on the rule, then the instrument is said to magnify 2, 3, or more times linear that known space. If roth of an inch is found to cover 2 inches on the rule, the instrument magnifies 200 times ; if 3 inches, 300 times ; if 4 inches, 400 times, and so on. In this way is determined the magnifying power of any combination of lenses, and the scale which is magnified is called a stage-micrometer. The size of objects may be measured by placing them directly on this micrometer ; but it is obvious that they cannot under high powers be brought into focus at the same time as the lines of the micrometer. An instrument called the eye-piece micrometer is therefore generally used. It consists of a fine scale, ruled on glass, and placed in the focus of the upper glass of the eye-piece. The value of each space of the eye-piece micrometer varies with the magnifying power of the object-glass which is placed on the microscope ; e.g., suppose we look at zrtvoth inch space of the stage micrometer with a magnifying power of 250 diameters, and find that the space thus magnified extends over 5 spaces of the eye-piece micrometer, the value of each space of the latter will obviously be svccth inch when a power of 250 diameters is 772 MICROSCOPIC APPARATUS. used. If a lower object-glass were taken—e. g., one which magnifies 50 diameters, it would then be found that the rescth inch space of the stage micrometer is equal to only one space of the eye-piece micrometer, so that, with this magnifying power, each space of the latter indicates z¢octh inch, These calculations have to be made for the magnifying powers of every microscope. When an object is to be measured, the stage micrometer is removed, and the object, placed on a slide and covered in the usual manner, is brought into focus, say, with a power of 250 diameters. If the object extends over 5 spaces of the eye-piece micrometer, its breadth would evidently be reco inch. In using the eye-piece micrometer, the marked side of the glass is put undermost. Hartnack’s eye-piece micrometer is the best. With this instrument, when using -a magnifying power of 500 or 600 diameters, we can estimate distances from svvoth to réssth of an inch with tolerable precision. Other kinds of eye-piece micrometers are also employed, such as the cobweb micrometer, where, by the motion of a delicate screw, fine wires, extended across the field of vision, can be separated from each other to known distances. In delineating minute structures, it is useful to have the image thrown on paper by means of a camera-lucida, or small prism, which can be easily attached to the microscope. The microscopist sometimes uses a compressorium, for the purpose of applying pressure to objects whilst they are under examination ; troughs for holding such plants as Chara, which are to be seen in water ; while various instruments for the dissection and examination both of animal and vegetable struc- tures are indispensable accessories. In testing the power of an in- strument, certain objects are used, in which peculiar markings occur, which can only be properly seen by a fine instrument. Either artifi- cial or natural objects may be chosen as test-objects. The former have been prepared by Nobert, a Konigsberg optician, and consist of glass plates, on which are ruled, with a diamond, systems of a hundred lines, which, 10 by 10, approach closer together and are finer, according to a definite standard. With most instruments only the 6th and 7th systems can be distinctly made out to be composed of separate lines. Superior instruments reach the 8th and 9th. No instrument has yet reached the 10th system, with its component lines. The best test- objects are the natural ones, as being regular and uniform in their markings, such as the scales of Podura plumbea or common Spring- tail, of Lepisma saccharina or sugar-louse, and the minute markings of the Diatomacez, as Pleurosigma Hippocampus. Certain markings oceur in these test-objects, which can only be seen properly by good microscopes. Microscopic Manipunation.—In viewing objects under the microscope they must be placed on slips or slides of glass, which should be of a uniform size, not less than three inches by one ; and MICROSCOPIC MANIPULATION, 773 they should be covered with round or square pieces of very thin glass, doth to rtcth of an inch thick. The slides ought to be made of thin plate-glass, and the covers of very thin crown or plate glass. In examining recent vegetable structures, it is best to moisten them with water, When the parts are dry, thin sections may be made either by means of slicing instruments or by a sharp knife. Many dry objects are well seen when immersed in Canada balsam. To preserve objects in a moistened state, the substances used are alcohol, a mixed solution of salt and alum and corrosive sub- limate, water containing a small quantity of creasote (five drops to the ounce), and glycerine. The objects, in such instances, are placed in shallow glass cells, or they are laid on the slides and covered with thin glass, which is cemented by means of japanner’s gold size, or black japan varnish. The methods of procedure are afterwards described. In proceeding to use the microscope it is necessary to have a variety of tools and apparatus to aid in preparing objects for investi- gation. These may be arranged beside the observer in such a way that they shall be always within his reach.* A small tray or box, with divisions, containing a pair of needles in handles (such as are used: for crotchet needles), a sharp knife or razor, a section-knife (such as- that invented by Valentine, and which bears his name), scissors, and a pair of sharp or fine needle-pointed forceps, about three inches long, are among the most essential instruments required. Glass slides may be arranged also upon the same tray for common use, and the thin glasses for covers should be kept in a small box by themselves. In manipulating the object to be examined certain re-agents are re- quired. These are:—1. Distilled water. 2. Methylated alcohol un- diluted, and also diluted in the proportion of about 1 part to 10 of distilled water ; it is the best preserving agent ; it removes colour and also air, 3. Ether, which dissolves resins, fats, and oils. 4. A solution of liquor potasse diluted to about 1 to 20; it swells up, and sometimes separates membranes of cells and tubes when they exist in condensed layers. 5. A solution of iodine in iodide of potas- sium of the following strength—namely, 1 grain of iodine to 3 grains of iodide of potassium, and an ounce of distilled water. 6. Chromic acid diluted in the proportion of about 1 to 30 or 40 of distilled water. The last two re-agents chiefly act by colouring the cell-walls or the contents of the cells. 7%. Sulphuric acid. 8. Oil, such as the finest of that obtained from coal, and known as mineral ‘oil, is to be recom- mended for examining and preserving objects. It does not become rancid, nor has it any affinity for oxygen. For the examination of pollen and spores there is nothing better. 9. One part of dry calcium * The following details are partly condensed from Schacht’s Treatise on the Microscope, and from the works of Hannover, Quekett, Jabez Hogg, and Beale. 774. MICROSCOPIC RE-AGENTS, chloride and 3 of water make also an excellent solution for preserving objects which do not contain starch. 10, Glycerine is the best pre- servative agent for cells containing starch. 11. Solution of Canada balsam (see Preservation of Microscopic Objects, page 783); and 12. Turpentine, are most useful re-agents and preservative materials for many dry preparations. 13. Nitric acid, used for separating cells. 14. Dilute hydrochloric acid may also be found useful in removing deposits of carbonate of lime. 15. Pyroligneous acetic acid. 16. A solution of carbonate of potass or soda. These sixteen substances should be arranged in stoppered glass bottles (excepting the Canada balsam, which should be placed in a corked bottle), fitting into a stand or box, so as to be of easy access; and small camel’s hair brushes, pipettes, and glass rods, should be arranged beside these bottles, in order to apply the fluid to the object. Lastly, the student should provide himself with a small note-book of good drawing-paper, on which he ought constantly to practise the delineation of the forms or outlines of the objects seen, and he should endeavour to colour them also when required, Numerous other requisites and appliances will suggest themselves during the course of investigations, and especially such as will secure cleanliness of the object, and of everything used in the research. 1. One who has any regard for his instrument will never suffer it or its lenses to be handled by those unaccustomed to their use. 2. The microscope, when not in use, must be kept under cover, generally under a glass shade. It should never be exposed in a chemical laboratory. 3. Its lenses must be cleansed when necessary by soft wash-leather, or a cloth which is used only for that purpose. The cloth best adapted for this purpose is old and frequently washed linen. 4, A separate cloth of a coarser kind is to be used for drying and wiping the slides and covers. 5. Covers of a middle size, from concave disks, such as watch-glasses, up to the size of a wine-glass without the stem, or other bell-shaped jars, are also required to protect the objects, if it is necessary to leave them for any length of time. The microscope is used to best advantage in a room which re- ceives its light from the north or west, or both. The light which is reflected from a white and motionless cloud opposite to the sun is the best that can be obtained. If gas-light is to be used, it ought to be softened by passing it through a blue glass shade before reaching the mirror ; but for exact observation, daylight is always to be preferred. When observations are made at night a sperm-oil lamp is used, and the light is transmitted to the mirror through a plano-convex lens, called a condenser. To correct the unpleasant glare attendant on the reflected light from an ordinary mirror, Mr. Handford makes a mirror of thin concave glass, three inches in diameter, the back rendered DIRECTIONS FOR USING THE MICROSCOPE. 775 white by plaster of Paris, This is mounted on brass, and fitted over the frame of the ordinary silvered mirror, thus not requiring the latter to be removed. The advantage is, that the whole rays reflected from the surface of plaster of Paris are brought into one focus, together with those reflected from the surface of the glass, and thus an equal and brilliant light is, produced. In viewing opaque objects, the light is thrown by the condenser directly on the object, and sometimes a metallic speculum, called a Lieberkuhn, is connected with the object- glass, by means of which an additional supply of light is obtained. In conducting microscopic observations great steadiness of the in- strument is required, which should accordingly be set upon a very firm and sufficiently large table, so that all the apparatus hitherto mentioned shall be within reach of the observer. It is proper also to begin the examination of objects with the lower magnifying powers, and to pass gradually from them to the use of the higher powers. By such means a far larger portion of the object is seen, and a more correct idea is obtained of the relations of the parts when considered as a whole. Object-glasses, varying from 30 to 50 diameters, are the best to begin with. The eye-glass of lowest power, that is, the longest one of the series, is also the one which ought generally to be used in the first instance, and as {long as the power can be increased by object-glasses of greater magnifying power, any more powerful eye- piece should not be used, for it must be remembered that the eye- piece merely magnifies an image produced by the object-glass. If, therefore, there be any defect in the image, it is magnified by the eye-piece. Directions by Smith and Beck for using the Compound Microscope. Before using the microscope, see that the mirror, object-glass, and eye-piece, are free from dust :—a little soft wash-leather should be used in cleaning these. The instrument should be placed on a steady table to avoid vibration. The best position for examination by day- light is with the window to the left hand, and the back partly turned toward the window, so that the light may fall directly upon the mirror, and not upon the observer’s face. At night, when a lamp is used, a shade should be placed if possible before the lamp, so as to screen the eyes from its glare. The nearer the observer can approach the window by day, and the closer the lamp can be brought towards the mirror at night (say from fifteen to twenty inches), the better ; as all the light that can be obtained is required for high magnifying powers ; and if too intense for some objects, can be easily modified by the mirror. When the microscope has a joint to the stand, it should generally be used with the body in an inclined position—at an angle of about 45°, this being much more convenient for the observer, and 776 ERRORS OF OBSERVATION. not so liable to injure the eye by overstraining it. The management of light, either natural or artificial, is of the greatest importance in microscopic observations. Ths may be regulated by altering the position of the mirror under the stage; the proper adjustment of which will soon be acquired by a little practice and observation. In adjusting the microscope for use, first place it in its proper position, and screw or slide on a low-powered object-glass, then look through the tube, and incline the mirror towards the light, moving it about until a clear bright light zs seen. The object may then be placed upon the stage and the focus adjusted by the rack movement. In examining any fresh object the lowest magnifying power should be first used, as a larger portion of it can be thus viewed at once, and a better general idea of its form, colour, etc., obtained. Afterward the higher powers may be employed, in order to reveal its minute structure. In viewing very delicate transparent objects, as fossil infusoria, thin vegetable and animal tissues, blood and milk globules, etc., a good clear light should be used, but the mirror should be inclined on one side more than usual, that the object may appear less brightly illumi- nated. This is what is termed “oblique illumination ”—the rays of light being reflected from the mirror, through the object, in an oblique direction, by which many delicate markings may be observed on some objects which could not be distinguished before, and the outline also rendered more distinct. In examining opaque objects, a low magnifying power should be used, and the light thrown wpon the object by means of the “ Con- denser,” which should be placed within two inches of it, and so arranged that a small circle of bright light may be seen upon the spot to be examined. When viewing objects in a drop of water, or examining a drop of any other liquid, a slip of thin glass should always be laid over it ; otherwise the liquid will evaporate, and con- densing on the object-glass, will render it dim. Sources oF Errors oF OBSERVATION.—Extraneous or accidental objects may be present, and may be derived from various sources. Thus, water too long used may bring before the eye both plants and animals of the lowest forms, which otherwise would not have been present. Fresh water is absolutely necessary. Particles of dust, or fibres from the cloths used in cleaning the glasses, may also add to the confusion. These consist, generally, of fibres of paper, linen, woollen, cotton, or silk fabrics, or minute hairs from the brushes used in manipulation. Air-bubbles are almost invariably a source of con- fusion to the microscopic observer in his first attempts ; but once seen and studied, they no longer distract the attention, and the microscopist soon gets into the habit of disregarding their presence. When seen by transmitted light they generally appear in the form of circles of larger or smaller diameter, with a dark rim surrounding them ; while CAUSES OF ERRORS, Tit with reflected light their rim appears white. Pressure under a glass cover may cause them to assume very irregular shapes, but pos- sessing the same properties in their margin or outline in their be- haviour with the light. It is also necessary to become familiar with the appearances of the lowest forms of animal and vegetable life, such, for instance, as the common forms of infusoria ; also the yeast, and such like plants; and the different forms of mould. A peculiar motion, known as “ Brownian motion,” is also a phenomenon which must be recognised. It is peculiar to all very small particles when they float in a very thin fluid medium. It is well seen in the fine granules of milk when mixed with water, and in the milky juices of plants. A magnifying power of 400 or 500 diameters is the best for this ob- servation. The eye itself is a source of deception, inasmuch as the phenomena known as “ musce volitantes” appear as if they were objects seen by the microscope. These are described as follows by Dr. W. Mackenzie in his Treatise on the Eye :— “The vision of objects on the surface or in the interior of the eye has attracted attention, chiefly in relation to a symptom to which the name of musce volitantes has been given. Any spectrum or visual appearance which is apt to impose on the mind, and lead one to think that flies are moving before the eye, is called a musca voldtans (fig. 952). é , The condition comprehends those sensations which arise from— 1. The layer of mucus and tears on the surface of the cornea; 2. Corpuscles between the external surface of the cornea and the focal centre of the eye; 3. Corpuscles between the focal centre of the eye and the sensitive layer of the retina. “ In hanging the head over the microscope, especially if one is affected with catarrh at the time, the globules, by gravitating to the centre of the cornea, not unfrequently appear to the observer so as to impede his view of the object, till by the act of nictitation he clears them away. In telescopic observations, also, the muco-lacrymal spectrum is apt to prove a source of annoyance. Thus, in looking at the sun through a tinted glass, the observer may be unable to dis- tinguish the spots on that body, being perplexed by what seems the reflection of some part of his own eye interposed between it and the sun. This is caused by the layer of mucus and tears on the surface of the cornea, “ Tf one looks at the flame of a candle two or three feet distant, or at the sky, through a hole made in a blackened card with the point of a fine needle, or through a convergent lens of short focus, such as the eye-glass of a compound microscope, on steadily regarding the luminous field presented to view, four sets of spectra will be seen (fig. 952), independent of the muco-lacrymal spectrum. The most remarkable appears nearest to the eye, and consists of twisted strings 778 CAUSES OF ERRORS IN OBSERVATIONS. of minute pearly globules, hung across the field of view (fig. 952 a). The second in point of remarkableness, and the farthest of the four from the eye, consists of watery-like threads, destitute of any globular appearance, and depending chiefly from the upper part of the field (fig. 952). I call the former the pearly spectrum, and the latter the watery spectrum. In two distinct planes, between those occupied by these two spectra, float two sets of globules, not aggre- gated into threads, but insu- lated. These constitute what I call the ‘insulo-globular spectra, The individual glo- bules of the set farther from the eye, being hazy and ill- defined, may be compared in appearance to small grains of sago (fig. 952 ¢). The globules of the set nearer to the eye are clear in the centre, ex- teriorly to which they present a sharp black ring, and still more exteriorly a lucid cir- cumference (fig. 952 d). Fig. 952. These four sets of spectra never mingle with one ano- ther, so as to change the order in which they stand before the eye; but the pearly spectrum always appears the nearest ; then the sharply- defined insulo-globular ; then the obscurely defined globules; and farthest away the watery threads. “ Almost every eye, even the most healthy, and which has never attracted the possessor’s attention by musce volitantes, exhibits the pearly spectrum, on being directed towards a luminous field, through a fine pin-hole, the eye-glass of a compound microscope, or a convex or concave lens of short focus. I have given it the same name of the pearly spectrum, from its resemblance to a string of pearls. Prevost had already called it apparence perlée, or simply perles, “The lines of the pearly spectrum are hung across the field of vision as often transversely as vertically. On first directing the eye towards the luminous field, in one or other of the methods just men- tioned, perhaps only a very few small pearly globules are perceived ; but after steadily regarding it for a short time, numerous strings of them are discovered, generally twisted in different forms, and present- ing a variety of knots, loops, and agglomerations. Sometimes they ‘ Fig. 952. Four sets of spectra, which are apt to cause errors in observations with the microscope. FOCAL ADJUSTMENT OF MICROSCOPE. 779 are so numerous as to form an extensive shower or cloud. The pearly threads are of different lengths; some of them very short, others stretching across the whole field. Not unfrequently some of them end abruptly in a sort of bulb. The globules or pearls forming the threads or rosaries’seemed joined together merely by apposition, without being contained in any tube. Sometimes, however, the globules are rather indistinct, and then the threads approach to a tubular appearance. The globules are always in single rows. They appear destitute of any nucleus. They are not all of one diameter, but are all smaller than the globules of the insulo-globular spectra. I have not satisfied myself that all the pearly threads occupy the same plane, although it is very evident that they are behind the insulo-globular spectra. “That portion of the pearly spectrum which appears in the centre of the field of view has but little real motion, less perhaps than the watery spectrum which is seen beyond it. Both partake, of course, in the motion of the eyeball ; and this gives to both a wide apparent motion. But if the field be examined towards its circumference, or if the eye be suddenly rotated upwards, other pearly spectra appear, which it is difficult or impossible for the observer to bring directly before him ; and which, when he succeeds in some measure in doing so, quickly subside again out of view, partly by a real motion of their own, partly by a wide apparent motion, owing to their obliquity in respect to the axis of vision. It is these last spectra, chiefly, which produce the pearly muscz volitantes.” There are also various optical phenomena caused by refraction, and which are necessary to be attended to. They depend, for the most part, upon a bad adjustment of the focus, or illumination of the object. The appearances are also most frequently associated with an increase of the magnifying power, and especially with the use of powerful eye- glasses. Large grains of potato-starch, pollen-grains, the thickened substance of woody tubes, and the cells of cartilage, are among the most common objects which exhibit such optical phenomena, which consist in a feeble and generally yellowish colouring of the edges of the objects when seen with particular foci. Foca ADJUSTMENT oF THE Microscopr.—The regulation of this adjustment is based on the fact that the microscope can only afford a view of one surface of an object at any given time, so that nothing is distinctly seen which lies above or below such a focal plane at that time; and the more flat the field of vision, the clearer and better will be the view of objects in that plane if the adjustment is correct. The more perfect the object-glass, and the greater the angle of aperture,* the more exact is this focal plane, and the more sensitive * The angle of aperture is that made by two lines from opposite ends of the aperture of the object-glass with the point of focus of the lens. A glass with a large angle of aperture shows objects clearly. The angle varies usually from 50° to 100°. Many glasses, however, are made with a much higher angle. Ross makes glasses of 170° of angular aperture. These are useful for observing minute organisms, such as Diatoms. 780 MICROSCOPIC OBJECTS, is the instrument to any small alteration of focus. The focal adjust- ment is made and varied by what is called a fine adjustment screw ; and the accurate adjustment of the object is judged of by the sharp- ness of the delineation of the image, as well as by the fineness and clearness of the outline. An experienced microscopic observer always uses the instrument with his finger and thumb grasping the fine adjustment screw, and would not be content. with his observation, although it was limited to a mere peep of the object, unless he had made the fine focal adjustment for himself. PREPARATION AND SELECTION OF OBJECTS FOR EXAMINATION. —Opaque objects require merely to be made smooth or level on one side, and to be fixed on the other. If the object is to be viewed by transmitted light, a section or slice sufficiently thin must be procured, a common sharp scalpel or razor are the instruments to use. The object must be moistened with water, and sometimes it is advisable to make the section under water. If the object is very small it may be em- bedded in solid paraffin (an ordinary paraffin candle), by melting it and pouring it over the object, and allowing it to cool; or it may be embedded in gum arabic in the following manner :—Make a cone of blotting paper about the size of the end of the finger, half fill it with a solution of gum as thick as possible, place the piece of tissue in the gum, and then set the cone in a vessel containing three or four times its bulk of rectified spirit for an hour or so, in order that the spirit may remove the water from the gum. Lastly, expose the cone to the air in a warm place, until the gum is hard enough to be cut. In making the sections wet the knife with water, and lay the sections in water to remove the adherent gum. A small piece of tissue may also be supported for the purpose of section between two slices of carrot or cork. Sections should be made in various directions, so that a correct knowledge may be obtained of the relation of the component parts. Maceration in water, and tearing the parts asunder with fine needles, are the best methods for obtaining the ultimate tissues of plants. Thin glass plates to cover the object under the microscope must be invariably used. They keep the object moist, they prevent the object-glass from being covered with vapour, and so rendered obscure ; and, lastly, they produce a slight pressure, by which the elementary parts of the substance may become separated from each other, so as to lie on one plane. The thin covers are not absolutely necessary where very low powers are used. In placing the object on the stage care must be taken not to bring it in contact with the object-glass of the instrument. It is also to be remembered that, in a compound microscope, the image is inverted, and that, consequently, the object is moved in a direction contrary to that of the image. The following list of tissues to be examined by the student of MICROSCOPIC OBJECTS. 781 Vegetable Histology is taken from the preparations used in the micro- scopical demonstrations given to the pupils of the Botanical Class in the University of Edinburgh :— Cellular Tissue.—Seaweeds, Confervee, Moulds and other Fungi; Lichens, Liverworts, pith of Elder and of the Rice-paper plants (Fatsia and Auschynomene), outer bark as of the Cork and of Ele- phantipes, succulent roots, stems, and fruits as Orange and Lemon. Schultze states that,by means of nitric acid and phosphate of potash, the cells of plants, young or old, hard or soft, may be isolated from one another so as to, give single cells, free and distinct, for microscopic examination. Protoplasm in the cellular tissue of young roots is well shown by the action of carmine or magenta. Nucleated Cells, — Scales of Onion, Vinegar plant, ripe fruit of Strawberry, Smut, ovules or very young seeds ; covering of ovary of Orchis mascula and maculata, shows bi-nucleated cells. Independent Cells.—Red-snow plant (Protococcus nivalis), Yeast plant (Torula), Chlorococcus vulgaris (yellow powdery matter on trees). Thickened Cells—Shell of Coco-nut, stone of Peach, Cherry and Nut, seed of Ivory-Palm and Date, gritty matter of Pear, scales of Cone. The thickening process in cells is seen in the rootlets of Mar- chantia (Liverwort). Pitted or Porous Cells,—Pith of Elder, stem of Common Balsam, outer covering of seeds of Gourd and Almond, Pith of Rosa tomen- tosa. Spiral Cells,—Leaves, stems, and aerial roots of many Orchids, rootlets of Oncidium, leaves of Pleurothallis ruscifolia and racemi- flora, leaf of Sphagnum, episperm of seeds of Collomia, Acanthodium, Calempelis scaber, Lophospermum, and Cobea, pericarp of Salvia, Isoetes lacustris. Reticulated Cells—lInner lining of anthers of Silene maritima and Pinguicula vulgaris ; Pith of Rubus odoratus and of Erythrina ; leaf of Sphagnum. Annular Cells—Inner lining of anther of Cardamine ‘pratensis ; stem of Opuntia. Stellate Cetls.—Centre of leaves of Juncus conglomeratus and other rushes, the transverse septa in petiole of Banana and Plantain ; petiole of Sparganium ramosum, Potamogeton, stems of many aquatic plants, inner lining of anther of Armeria. Ciliated Cells—Spores of Vaucheria and some Fuci. Filamentous Cells,—The structure of many Fungi. Pollen Cells,—Anthers of Tulip, Lily, Passion-flower and Mallow (echinated), Acacia (cells united in fours), Zamia, Cycas, Tropeolum, Gloxinia, Colocasia, Sherardia arvensis, Mimulus moschatus, Juncus, Linum, Scorzonera hispanica, Tragopogon porrifolius, pollinia of As- clepias and Orchids. 782 MICROSCOPIC OBJECTS. Pollen Tubes—CEnothera, Antirrhinum, Hibiscus, Linaria, Gesnera, Crocus. Embryonic Cells.—Orchis, Listera, Hippuris, Euphrasia, Draba. Spores or Reproductive Cells—In Oryptogamous plants, Ferns, Mosses, Licheris, Alge, and Fungi, Zygnema when conjugating. Cells with Siliceous Covering. — Diatoms, cuticle of grasses, Equisetum. Cells encrusted with carbonate of Lime.—Chara, Epidermal Cells—Leaves of Hyacinth, petals of Pelargonium, Apple, Duckweed, Hellebore, and Digitalis. Hairs.—On leaves, and in pappus of Composite, Cotton (twisted), articulated hairs on leaves of Goldfussia and Alstroemeria ovata, pap- pus of Trichinium, moniliform hairs on stamens of Tradescantia, stel- late hairs of Deutzia, Viburnum Opulus, Ivy, Hollyhocks, and Fatsia papyrifera, peltate hairs of Malpighia urens, glandular hairs of Nettle, Loaza, Chinese Primrose, Drosera, and Dionza, branched hairs Ver- ‘ bascum, forked Apargia hispida, Alyssum, stalked cruciate hairs Arabis sinensis, clubbed hairs on filament of Verbascum nigrum, capitate hairs of Scrophularia nodosa, beaded hairs Mirabilis Jalapa. Glandular Cells—Sweet-Brier, Passiflora lunata, Ice-plant, Lilac, Cinchona, lupuline glands of Hop, Rhamuus, Rottlera, Aloysia, Mentha, in Pitchers of Nepenthes, and Sarracenia. Scaly Cells—Ferns, as Polypodium sepultum, Niphobolus, Ceterach, and Nothochlena levis, scales of Hippophie, Begonia, Olive, and Eleagnus. Starch in Cells—Potato, Arrow-root, Cereal grains, Bean and Pea, Habenaria bifolia, rhizome of Florentine Iris. Raphides,—Hyacinth, Rhubarb, Arum, Colocasia, Onion, Squill, Balsam, Cactus, Lemna trisulca, Ficus (cystoliths), Aloe, Banana, petal of Ornithogalum, bark of Salisburya adiantifolia, leaves of . Dieffenbachia seguina (biforines), spheeraphides, or globular clusters of raphides, seen in the parenchyma of the leaf of the tea-plant. Atr-Cells and Lacune.— Rush, Sparganium ramosum, Papyrus, Limnocharis Plumieri, Hippuris (mare’s tail), Nymphea, and other aquatic plants. Oil-Cells.—Rind of Orange and Lemon, leaves of Hypericum and Myrtaceze. Chlorophytl-Cells,—Mosses, Vallisneria, Anacharis, Chara, Green Seaweeds. Colour-Cells—Leaf of Rottlera tinctoria, petals of Pelargonium and Geranium, Strelitzia. One way of preparing the petal of Pelar- gonium is by immersing it in sulphuric ether for a few seconds, and then allowing the fluid to evaporate. Another mode is simply to dry the petal, immerse it for an hour or two in spirit of turpentine, and then put it up in new Canada balsam. MICROSCOPIC OBJECTS. 783 Stomata.—Cuticle of Leek, Hyacinth, Begonia, Oleander, Lilium, Equisetum, Box, Gasteria, Marchantia, Crinum, Yucca, Billbergia, Mistleto, Hellebore, Ivy. Antheridia and Archegonia. —Prothallus of Ferns, Mosses, Fucus, Marchantia, spermatozoids in Ferns and Chara. Conjugating Cells,—Zygnema nitidum, Tyndaridea, Cylindrocystis, Desmidiez. Vascular Tissue.—Young stems of herbaceous plants. Spiral Vessels—Canna bicolor, Pitcher plant (Nepenthes), Banana and Plantain, Cactus, Hyacinth, Asparagus, Balsam, Strelitzia, branching spirals in Mistleto, Long-leek, and Anagallis, Compound spirals in Water-lily and Lilium candidum ; a loose spiral in stalk of Horsetails (Equisetum). Annular Vessels—Opuntia vulgaris, Leek, Equisetum maximum. Dotted or Pitted Vessels—Sugar-Cane, Nepenthes, Willow, Ash, Bramble, Clematis Vitalba, Papaver somniferum, Balsam. Tylosis in pitted vessels of Walnut, Hazel, Vine, Oak, Bignonia. Reticulated Vessels——Garden Balsam. Scalariform Vessels—Rhizomes and stalks of fronds of Ferns, Polystichum, Osmunda, Asplenium, Cheilanthes, Pieris. Laticiferous Vessels.— Ficus elastica, Euphorbia, Tragopogon, Chelidonium, Lactuca, Isonandra Gutta, Dandelion. Woody Tissue.—Stems of trees, inner bark especially of plants yielding useful fibres, as Flax, Jute, Hemp, Boehmeria, Lace Bark tree, Cuba Bast; root of Elder, Cabbage. Punctated Woody Tissue.-—Stems of Coniferze when cut parallel to medullary rays, Pinus, Abies, Wellingtonia (Sequoia), Araucaria, fossil stems, Cycas, Illicium, Daphne Mezereum ; and with spirals in Yew. Ovules and Embryo.—Crucifere, Chelidonium, Cactus (shows branched funiculus), Passion-flower (dicotyledonous embryo) ; Orchids and Lilium (monocotyledonous). Seeds.—Papaver somniferum, Gentiana lutea, Eccremocarpus scaber, Lepigonum marinum,} Spheenogyne speciosa, Erica cinerea, Calluna vulgaris, Oxalis rosea. PRESERVATION oF Microscopic Ossects.—The following ap- paratus is required—viz., glass-slides ground at the edges, and of the requisite standard size, 1 by 3 inches, with circular glass covers ; preserving agents, cement, and turn-table for mounting and making cells. Among the preserving media for vegetable substances are—a solution of chloride of calcium, glycerine, copal varnish, mineral oil, Canada balsam, Pyroligneous acid. .Some recommend the use of arsenic in preserving objects. Make a saturated solution of arsenious acid in boiling water, allow it to cool, and then filter. Then take of this solution one ounce, of glycerine one ounce, and of gum arabic one ounce ; allow this to stand for three weeks, and then filter through 784 PRESERVATION OF OBJECTS. cambric. Among the cements used for vegetable objects are the fol- lowing :—Asphalte, japanner’s gold size, black japan sealing-wax varnish, Robinson’s liquid glue, gum mastic and caoutchouc dissolved in chloroform. Objects are put up (i.e. preserved) either as dry or as wet objects. For dry objects, the oils and the Canada balsam are the preservative materials, but they are not suited for wet objects. Before mounting objects in Canada balsam they must be perfectly clean and free from moisture. The moisture is got rid of by immersing them in rectified spirit for an hour or so; the spirit is then removed by placing the tissue for a few minutes in turpentine or oil of cloves in a watch- glass or on a slide. Both of these agents, owing to their high re- fractive index, render tissues transparent. In this respect clove oil is more powerful than the turpentine, and therefore it is preferred when great transparency is desirable. When the tissue is sufficiently clari- fied, a drop of Canada balsam solution is placed on a slide, the tissue is transferred to it, the cover-glass applied and gently pressed down in order to flatten the tissue. The balsam soon dries, so that the cover-glass is permanently fixed. The solution of Canada balsam is thus prepared :—Place the ordinary kind obtained from the shops in a saucer, cover it with blotting-paper to protect it from dust, place it near the fire for some days, until the balsam is so dry that it becomes as hard as ice when it cools, Dissolve this perfectly dried balsam in chloroform, or turpentine, or benzole (the latter is to be preferred), and keep it in a corked bottle. The solution ought to be as thin as milk. The mounting of objects in this solution of dried balsam has quite superseded the old method of mounting objects in undried balsam with the aid of heat. The solution of chloride of calcium is adapted for the preservation of wood and leaves, and for most kinds of isolated tissue. The colouring matter in the cells, however, is always more or less altered by it, while grains of starch, if present, swell up and can scarcely be recognised. The strength of the solution is one part of lime to three of water. Glycerine is used in equal parts mixed with camphor water, which prevents the tendency to mildew. The chlorophyll and the grains of starch remain unchanged, and the laminz of the starch appear more beautiful after a few hours’ immer- sion in the glycerine solution. Canada balsam and copal varnish are used for the preservation of dry and fossil woods. Thin sections should be made, and treated as above directed. If the entire structure of any exogenous wood is required to be examined, the sections must be made both in the transverse or horizontal, and in the longitudinal or vertical direction. The vertical section, made parallel to the medullary rays, or, in other words, along the course of them, shows the nature of these cellular rays, which proceed horizontally from the centre, enclosed between the layers of woody fibres, and which are known to the cabinetmaker as the silver grain of the wood. In coni- PRESERVATION OF OBJECTS. 785 ferous trees, as the pine, this section shows also the beautiful puncta- tions on the walls of the fibres. The tangential-vertical section is a slice across the ends of the medullary rays, and exhibits the form and arrangement of the cellular tissue in them. The cells of the rays are seen projecting between the fibres of the wood. These vertical sections show the form, size, and connections of the woody tubes and the spiral, reticulated, and dotted vessels, In endogenous trees hori- zontal and vertical sections are also required. Peat wood requires to be digested in a strong solution of carbonate of soda, and fossil woods which have been converted into carbonate of lime should be digested in dilute hydrochloric acid (1 of acid to 20 of water). Schleiden gives the following method of preserving minute struc- tures for the microscope. Upon a glass slide of the common form two narrow slips of paper are gummed, of a thickness proportioned to the object, and at a distance which is regulated by its size. Between these the object is laid in a drop of solution of chloride of calcium (60 grains to half-an-ounce of water). A thin slip of glass, sufficient’ to cover the object and paper slips, is put on; the slips are gummed, and the thin glass applied to its place, where it is retained by the gum drying. The whole may be secured by pasting a long slip of paper over all, with a hole for the object. The method has the advantage of preventing all running in, which is so apt © to happen when asphalte varnish is employed. Chloride of calcium, being deliquescent, never dries up, and, if evaporation takes place, water is easily introduced at the open sides of the thin glass. The points to be attended to are—l, that the paper between the glasses |.o04 crus be thick enough to prevent much pressure on the | orcmo. object, and not so thick as to allow it to float about or fall out at the side; 2, that the drop of solution be not —_Fig. 953. too large, but covering the object, and yet not reach- ing the paper. Glycerine may be used in place of chloride of calcium in cases where the objects are very delicate, or contain chlorophyll or albumen. Small specimens for the microscope, such as Diatoms and Desmidiex, and many small Seaweeds, as well as vegetable tissues, are put up on slides (fig. 953), in the centre of which there is a circular cavity formed by a layer of asphalte,* and covered by a circular piece of thin glass. Fig. 953. Glass slide for microscopic preparations, 3 inches long and 1 inch broad. In the centre is a ring of asphalte, forming a cell to contain fluid ; the object marked by a + in the centre is covered by a circular piece of thin glass fitted to the asphalte rim. The name of the object is often written on the glass, but perhaps it is preferable to write the name on coloured paper, and attach it to the glass by isinglass or fine bookbinder’s glue. * Prepared asphalte is better than gold size or black japan varnish, as it dries more rapidly, and is less liable to run. It can be procured from opticians. 3 E 786 PREPARATION OF CELLS. The asphalte is applied by means of a hair pencil, the slide being placed on a turn-table (fig. 954), which has circular marks on it corre- sponding to the required dimensions of the cavity. The depth of the cavity can be varied according to circumstances, by putting one or more layers of asphalte. After the thin glass cover is put on, it is luted carefully with asphalte. The cavity is filled with distilled water, weak pyroligneous acid, alcohol, diluted glycerine, a very weak solution of creazote (one drop to the ounce of distilled water), or some other fluid. When specimens are very minute the asphalte cell is not required ; the thin glass is applied at once to the slide, a drop or two of the fluid being inserted along with the specimen. In the case of some dry preparations, as pollen-grains and the fine-lined Diatoms, no fluid whatever is required, but precautions must be taken against the access of damp. Canada balsam is useful in some instances, The specimen is laid on a slide,‘then a drop of the solution of Canada balsam is put on it, and the thin glass above all. It is then set aside to dry, and ultimately a rim of asphalte is made round the margin of the glass cover. Canada balsam is well fitted for many Diatoms, and for thin sections of woods. In putting up woods, the specimen is placed in the centre of the slide, a drop of turpentine is insinuated below it, with a camel- hair pencil, in order to expel the air; a solution of Canada balsam is then applied, and the same procedure is followed as above. To MAKE CELLS, AND TO FIX THE THIN GLass Covers.—The cells are made either round or square by thin layers of cement, according to the depth required. Perhaps the round ones are neater, but they require circular pieces of glass for covers, and by the aid of the turn- table (fig. 954) the roundness of the mounting can be made with perfect accuracy. The cover is laid gently down, so as to float on the solution in which the object lies, and by pressing carefully on the cover, the superabundant fluid is made to pass out by the edges, and may be taken up by blotting paper. A thin layer of asphalte, or gold size, may be placed round the edge, which will gradually harden and completely seal up the preparation. Fig. 954. Fig. 954, Turn-table for making the circular rim of asphalte ; b, a piece of mahogany; @, a circular piece of brass, which can be moved round by the hand, and has two brass springs on its surface for holding a glass slide firm. In the centre of the brass disc are circular markings fitted for the size of asphalte cells required. These marks being seen through the slide laid above them, guide the hand in making the circular asphalte rim, the brass disc being turned round during the application. FOSSIL SECTIONS. 787 On preparing fossils for microscopic examination, Mr. Alexander Bryson remarks :—* The usual mode of proceeding in making a section of fossil wood is simple, though tedious. The first process is to flatten the specimen to be operated on by grinding it on a flat Jap made of lead charged with emery or corundum powder. It must now be rendered perfectly flat by hand on a plate of metal or glass, using much finer emery than in the first operation of grinding. The next operation is to cement the object to the glass plate. Both the plate of glass and the fossil to be cemented must be heated to a temperature rather inconvenient for the fingers to bear. By this means moisture and adherent air are driven off, especially from the object to be operated on. Canada balsam is now to be equally spread over both plate and object, and exposed again to heat, until the redundant turpentine in the balsam has been driven off by evaporation. The two surfaces are now to be connected while hot, and a slow circular motion, with pressure, given either to the plate or object, for the purpose of throwing out the superabundant balsam and globules of included air. The object should be below and the glass plate above, as we then can see when all the air is removed, by the pressure and motion indicated. It is proper to mention that too much balsam is more favourable for the expulsion of the air-bubbles than too little. When cold, the Canada balsam will be found hard and adhering, and the specimen fit for slitting. This process has hitherto been performed by using a disc of thin sheet-iron, so much employed by the tinsmith, technically called sheet-tin. The tin coating ought to be partially removed by heating the plate, and when hot rubbing off much of the extraneous tin by a piece of cloth. The plate has now to be planished on the polished stake of the tinsmith, until quite flat. If the plate is to be used in the lathe, and by the usual method, it ought to be planished so as to possess a slight convexity. This gives a certain amount of rigidity to the edge, which is useful in slitting by the hand ; while by the method of mechanical slitting, about to be described, this convexity is inadmissible, The tin plate, when mounted on an appropriate chuck in the lathe, must be turned quite true, with its edge slightly rounded and made perfectly smooth by a fine-cut file. The edge of the disc is now to be charged with diamond powder. This is done by mingling the diamond powder with oil, and placing it on a piece of the hardest agate, and then turning the disc slowly round ; and holding the agate with the diamond powder under ‘a moderate pressure against the edge of the disc, it becomes thoroughly charged with a host of diamond points, becoming, as it were, a saw with invisible teeth. In pounding the diamond some care is necessary, as * On an improved Method of preparing Siliceous*and other Fossils for Microscopic Investigation, with a description of a new Pneumatic Chuck, By Alex. Bryson, in Edin. N. Phil, Journal, N. &., iii. 297. 788 PREPARATION OF FOSSIL SECTIONS also a fitting mortar. The mortar should be made of an old steel die, if accessible ; if not, a mass of steel, slightly conical, the base of which ought to be 2 inches in diameter, and the upper part 1} inch. A cylindrical hole is now to be turned out in the centre, of #ths of an inch diameter, and about 1 inch deep. This, when hardened, is the mortar; for safety it may be annealed to a straw colour. The pestle is merely a cylinder of steel, fitting the hollow mortar but loosely, and having a ledge or edging of an eighth of an inch projecting round it, but sufficiently raised above the upper surface of the mortar, so as not to come in contact while pounding the diamond. The point of the pestle ought only to be hardened and annealed to a straw colour, and should be of course convex, fitting the opposing and equal concavity of the mortar. The purpose of the projecting ledge is to prevent the smaller particles of diamond spurting out when the pestle is struck by the hammer. Mr. Bryson has contrived an instrument for slitting fossils. The Fig. 955, instrument is placed on the table of a common lathe, which is, of course, the source of motion. (Fig. 955.) It consists of a Watt’s parallel motion, with four joints, attached to a basement fixed to the table of the lathe. This base has a motion (for adjustment only) in a horizontal plane, by which we may be enabled to place the upper Fig. 955. Mr, Bryson’s instrument for slitting fossils. FOR THE MICROSCOPE. 789 joint in a parallel plane with the spindle of the lathe. This may be called the azimuthal adjustment. The adjustment, which in an astronomical instrument is called the plane of right ascension, is given by a pivot in the top of the base, and clamped by a screw below. This motion in right ascension gives us the power of adjusting the perpen- dicular planes of motion, so that the object to be slit passes down from the circumference of the slitting-plate to nearly its centre, in a perfectly parallel plane. When this adjustment is made accurately, and the slitting-plate well primed and flat, a very thin and parallel slice is obtained. This jointed frame is counterpoised and supported by a lever, the centre of which is movable in a pillar standing perpendicu- larly from the lathe table, Attached to the lever is a screw of three threads, by which the counterpoise weight is adjusted readily to the varying weight of the object to be slit and the necessary pressure required on the edge of the slitting-plate. The object is fixed to the machine by a pneumatic chuck. It consists of an iron tube, which passes through an aperture on the upper joint of the guiding-frame, into which is screwed a round piece of gun-metal, slightly hollowed in the centre, but flat towards the edge. This gun-metal disc is perforated by a small hole communicat- ing with the interior of the iron tube. This aperture permits the air between the glass plate and the chuck to be exhausted by a small air syringe at the other end. The face of this chuck is covered with a thin film of soft India-rubber not vulcanised, also perforated with a small central aperture. When the chuck is properly adjusted, and the India-rubber carefully stretched over the face of the gun-metal, one or two pulls of the syringe-piston is sufficient to maintain a very large object under the action of the slitting-plate. By this method no time is lost ; the adhesion is made instantaneously, and as quickly broken by opening a small screw, to admit air between the glass plate and the chuck, when the object is immediately released. Care must be taken, in stretching the India-rubber over the face of the chuck, to make it very equal in its distribution, and as thin as consistent with strength. When this material is obtained from the shops, it presents a series of slight grooves, and is rather hard for our pur- pose. It ought, therefore, to be slightly heated, which renders it soft and pliant, and in this state should now be stretched over the chuck, and a piece of soft copper wire tied round it, a slight groove being cut in the periphery of the chuck, to detain the wire in its place. When by use the surface of the India-rubber becomes flat, smooth, and free from the grooves which at first mar its usefulness, a specimen may be slit of many square inches, without resort being had to another exhaustion by the syringe. But when a large, hard, sili- ceous object has to be slit, it is well for the sake of safety to try the syringe piston, and observe if it returns forcibly to the bottom 790 PREPARATION OF FOSSIL SECTIONS, of the cylinder, which evidences the good condition of the vacuum of the chuck. After the operation of slitting, the plate must be removed from the spindle of the lathe, and the flat lead lap substituted. The pneumatic chuck is now to be reversed, and the specimen placed in contact with the grinder. By giving a slightly tortuous motion to the specimen, that is, using the motion of the various joints, the object is ground perfectly flat when the length of both arms of the joints is perfectly equal. Should the leg of the first joint on the right hand side be the longer, the specimen will be ground hollow; if shorter, it will be ground convex. But if, as before stated, they are of equal length, a perfectly parallel surface will be obtained. In operating on siliceous objects, I have found soap and water quite as speedy and efficacious as oil, which is generally used ; while calcareous fossils must be slit by a solution of common soda in water. This solution of soda, if made too strong, softens the India-rubber on the face of the pnuematic chuck, and renders a new piece necessary ; but if care is taken to keep the solution of moderate strength, one piece of India-rubber may last for six months. The thinner and flatter it becomes the better hold the glass takes, until a puncture occurs in the outer portion, and a new piece is rendered necessary. The polishing of the section is the last operation. This is per- formed in various ways, according to the material of which the organ- ism is composed. If siliceous, a lap of tin is to be used, about the same size as the grinding Jap. Having turned the face smooth and flat, a series of very fine notches are to be made all over the surface. This operation is accomplished by holding the edge of an old dinner-knife almost perpendicular to the surface of the lap while rotating ; this produces a series of criddies, or slight asperities, which detain the polishing substance. The polishing substance used on the tin lap is technically called lapidaries’ rot-stone, and is applied by slightly moistening the mass, and pressing it firmly against the polisher, care being taken to scrape off the outer surface, which often contains grit. The specimen is then to be pressed with some degree of force against the revolving tin Jap or polisher, carefully changing the plane of action by moving the specimen. in various directions over the surface. To polish calcareous objects, another method must be adopted, as follows :— A lap or disc of willow wood is to be adapted to the spindle of the lathe, 3 inches in thickness, and about the diameter of the other laps (10 inches), the axis of the wood being parallel to the spindle of the lathe, that is, the acting surface of the wood is the end of the fibres, or transverse section. This polisher must be turned quite flat and smoothed by a plane, PREPARATION OF DIATOMS. 791 as the willow, from its softness, is peculiarly difficult to turn. It is also of consequence to remark that both sides be turned so as that the lap, when dry, is quite parallel. This fap is most conveniently adapted to the common face chuck of a- lathe with a conical screw, so that either surface may be used. This is made evident when we state that this polisher is always used moist, and, to keep both surfaces parallel, must be entirely plunged in water before using, as both surfaces must be equally moist, otherwise the dry will be concave, and the moist sur- face convex. The polishing substance used with this dap is putty powder (oxide of tin), which ought to be well washed to free it from grit. The calcareous fossils being finely ground, are speedily polished by this method. To polish softer substances a piece of cloth may be spread over the wooden lap, and finely levigated chalk used as a polishing medium. In all instances slides should be labelled with the name, locality, and date, and they should be numbered and catalogued, so that they may be easily referred to when put up in cases, such as that shown in fig. 956, or in cabinets.* The Diatomacee being either free, or attached to Alge, etc., dif- ferent modes must be resorted to for collecting them. Those which are attached require only (either at the time or after being dried) to be rinsed gently in fresh water to get rid of the sand or mud, and salt if any, and then placed in a small saucer in boiling water, with a few drops of nitric or muriatic acid. The cuticle being corroded, the ‘Diatoms fall to the bottom, the floating Algz are taken out with a glass rod, and the residue washed. This step is merely preparatory to that of burning or boiling the objects. If the Diatoms be free, they should, as far as possible, be gathered free from sand or mud, by skimming the surface of the pond or pool with an iron spoon; but as much mud and sand may still be mixed with them, they ought to be afterwards placed in a saucer in a little water, and exposed to the sun for a day‘or two. A tumbler or hand-glass will prevent too much evaporation. Diatoms, if recently gathered and alive, will come to the surface of the sediment, or water, or both, and this affords an easy ‘ mode of separating certain species. They may now be skimmed off with a small spoon, or, what is preferable, a camel’s hair pencil, and removed to clean water ; and this process is to be repeated till the mud is got rid of entirely. As for preparing the specimens, they may be either burned, or boiled in nitric acid. For the isolated Diatoms,f as Navicula, Pleurosigma, Cocconeis, etc., boiling is preferable; but for the *In making sections of minute objects, such as Diatoms, they are mixed with. plaster of Paris and mucilage, and then the whole is sliced by means of a sharp razor. Small pieces of wood are sometimes put into a slit in a cork, and then the whole sliced. | + By free Diatoms are meant those that are not parasitical. By isolated or solitary Diatoms are meant those not connected nor cohering together into threads or plates, or by a stipe, tube, or gelatine. 792 PREPARATION OF DIATOMS. others, as Synedra, Fragilaria, Melosira, Meridion, etc., if one wishes to have a few frustules cohering together to show their habit, then burning must be adopted, as the acid separates them joint by joint, and valve from valve. This is accomplished by arranging the specimens in the centre of a glass slide, and laying them on a thin iron slide, and placing the whole within a little iron tray, closed in the form of a slipper, to exclude ashes. This is exposed to the fire till the slide is ted hot. The slide is now allowed to cool, and the specimen is ready Fig. 956. for being covered either with or without the intervention of balsam. The latter is called dry mounting, and is best accomplished by making a ring of asphalte, and following the same process as for liquid mount- ing, but without liquid. When nitric acid is to be used, the cleaned Diatoms are put into a large-sized test tube of German glass, with as little water as possible, and about one part of nitric acid to four of water. After being boiled for two or three minutes over a spirit-lamp, the Diatoms must be allowed to subside, and as much liquor as possible poured off, with any fragments of vegetable matter floating in it. This Fig. 956. A case for containing slides after being prepared. There are three divisions, each containing twelve slides, two of which are shown projecting above the lower division of the box, the lid being hollowed to receive them. Numbers corresponding to those on the slides are fastened on the partitions at the sides of the grooves which retain the slides, On the front of the box a notice of the numbers contained in it should be fastened. Corre- sponding numbers, with full particulars as to the preparations, ought to be entered in a book, which serves as a catalogue, in which there should be first a numeral progressive series, and then an alphabetical register for genera. Card boxes for holding 24 slides are made by Smith and Beck, and others, price one shilling each. They are excellent for form- ing a general collection. Cabinets are also made for slides, consisting of drawers half-an- inch deep (including the bottom) divided so as to hold 30, 40, or 50 slides all on their back - the drawers being slightly bevelled at their divisions on one side, so that the slides may be tilted up by pressing them down. Cases such as that in Figure 956 may be placed on their ends, like books on a shelf, so as to keep the slides horizontal, and prevent the object from gravitating to one side of the disc. SLIDES AND COVERS. 793 boiling sometimes suffices, but it is always preferable to add some of the strong acid, and boil the whole again for a few minutes, so as to dissolve any vegetable or animal substances remaining. As the siliceous covering is very thin, and easily broken by a sudden change of temperature, care must be taken in washing away the acid, either to use boiling water or to allow the Diatoms in the test-tube to cool. When a sufficient supply of pure distilled water can be easily got, it alone ought to be used for washing them; but, when that is not the case, ordinary water may be employed for the first washing, but the after washings must be all made with distilled water until the acid is got rid of. After being thoroughly washed, the Diatoms are kept ina small test-tube with some distilled water. In taking the specimens from the test-tube, in order to put them on the slide, a pipette or dropping-tube is employed, having a bore of about scth to goth of an inch at its lower end. Mr. Jackson remarks that it is desirable that no object submitted to higher power than a quarter-inch objective of 75° aperture should ever be mounted under a cover thicker than rivth of an inch ; if the aperture exceeds 120°, the best thickness for the cover is z¢cth of an inch.* Glass of this thickness can easily be cut with a good writing diamond, when laid on a piece of plate glass.f To clean the covers it is recommended to put them in strong sulphuric acid for a day or two, and then wash them repeatedly with water ; after that to place them, a few at a time, on a tightly-stretched clean cambric handker- chief, and to rub them very gently with another handkerchief on the finger. They should then be removed to a clean box, with forceps, and carefully kept from dust and from contact with the fingers. The covers should be sorted according to their thickness, and this is done at once by Ross’s “lever of contact,” which consists of a long slender index, having a projecting touch near the centre of motion, which is kept in‘contact with a plane surface by means of a spring. When a piece of glass is inserted under the touch, the. index points to the thickness on a graduated are. The thickness may also be measured in the usual way by placing a fragment in the pliers, with the edge upwards, under the microscope, armed with an inch object-glass and an eye-piece micrometer. } Works on THE Microscopr.—the following works may be con- sulted by the student :—Carpenter, The Microscope and its Revelations ; * On account of the brittleness of the glass, covers thinner than 1-140th or 1-150th of an inch are, in the hands of most manipulators, practically useless, as they break by the mere wiping or mounting, and glass 1-150th of {an inch is not too thick either for Smith and Beck’s 1-5th object-glass with 100° of aperture, or Ross’s 1-Sth with 156° of aperture ; but when dry mounting is adopted, the object ought to be arranged on the under side of the cover, thus bringing it as near the lenses as possible, + Quekett on the Microscope. 2d Rdit. p. 265. t Quarterly Journal of Microscopical Science, i. 141. 794 WORKS ON THE MICROSCOPE. Schacht, The Microscope and its Application to Vegetable Anatomy and Physiology, translated by Currey ; Hannover on the Construction and Use of the Microscope, edited by Professor Goodsir ; Beale, How to work with the Microscope ; Hogg on the Microscope ; The Quarterly and Monthly Microscopical Journals; Griffith and Henfrey, Micro- graphical Dictionary ; Pritchard’s Microscopic Illustrations ; Robin, Du Microscope et des Injections; Dippel, das Mikroscop ; Gosse, Evenings at the Microscope ; Lankester’s Half-hours at the Microscope, illustrated by Tuffen West; Lewis on Seaside Studies; Prichard on Infusoria ; Woodward on Polarised Light ; Griffith’s Elementary Text- book on the Microscope. Ross’s Microscoprs 1n 1855—OBsEcTIVES AND PRICES. Object Glasses, Angle of Magnifying Powers, with Prices Focal Length. Aperture. Four Eye-pieces. : A B Cc D| £ s. 2 inches 12 degs. 20 30 40 60} 2 0 Linch 16°; 60 80 100 120] 3 0 I 22 |. 60 80 100 120] 310 es 65 ,, 100 130 180 220| 5 5 iy 85, 220 350 500 620| 5 5 ws 125 ,, 220 350 500 620] 7 10 de 5s 135, 320 510 700 910] 10 0 a 130 ., 400 670 900 1200] 11 0 4s 150 ,, 400 670 900 1200] 12 0 TZ 170: 5 650 $00 1250 2000/18 0 GuNDLACH’s ACHROMATIC OBJECT GLASSES. Linear Magnifying-Power | Angl 7 No. Fosi. ea ee ap Price. In. A B Cc £3. d. 00 a4 14 22S 10 deg} 110 0 0 13 20 380 45 15/1 7 6 1 1 30 45 «65 20 5,/1 5 0 2 3 65 90 120 38 ,,:| 1° 5 0 3 4 90 125 170 50 ,,/1 5 0 4 4 188 185 250 80 ,, | 115 0 ae ‘i . i 4 275 375 500 150 ,,|2 5 0 64 Without correction | 7 450 625 830 165 ,,|/3 5 0 6B With correction . ds 450 625 830 165 ,,|4 0 0 78 Immersion with cor- rection i ds 600 835 1200 175 ,,/4 0 0 8 Immersion with cor- rection vx | 900 1250 1700 | 175 6 6 0 COLLECTING AND DRYING OF PLANTS. 795 Last oF tHE Principat Microscopz Maxers.—Ross, Powell and Lealand, Smith and Beck, Crouch and Baker, in London; Adie, Bryson, in Edinburgh; Field, Parkes, in Birmingham; Dancer, in Manchester ; King, in Bristol; Nachet, Hartnack, in Paris; Schiek, Pistor, in Berlin: Ploesl, in Vienna. IL—On Coiiectine AnD EXAMINING PLANTS, AND ON THE Formation oF A HERBARIUM. INSTRUMENTS AND APPARATUS,—In examining the characters of plants, with a view to classification, the chief instruments required are a lancet-pointed knife, a small pair of forceps, and a lens from } to 1 inch focus. With the view of holding the object steadily the blades of the forceps may be made so as to be fastened by a sliding button. In more minute examinations, the simple or compound microscope must be called into requisition. In selecting specimens, care should be taken to have the plants in a perfect state, or with all the character- istic parts present. The entire plant should be taken when practicable ; when that is not the case, then those parts should be taken on which the generic and specific characters are founded. The roots should always be carefully washed at the time the plants are gathered. In most cases, particularly in specimens of Umbellifere, Leguminose, Composite, Rosx, etc., it is of importance that both flowers and fruit should be preserved. In the case of Willows the young shoot, with its fully developed leaves, as well as the male and female flowers, are requisite. In Rubi, specimens of the young shoots must be taken. When bulbs or tubers exist, they should be preserved, either in an entire or split condition ; and when there is much mucilaginous matter in them, they may be enveloped in small pieces of paper, so as to prevent them from adhering to the drying paper. In the case of Ferns, two fronds are necessary to make a perfect specimen, showing both surfaces, along with a portion of the rhizome. Entire specimens of Graminez and Cyperacee should be collected ; these, when long, may be bent into one or more folds, corresponding to the size of the paper on which they are to be fastened, the folds being temporarily retained by small slips of paper having slits in the centre. No bad specimens ought to be preserved. In taking up the roots of plants, a small Digger or trowel is used, 7 or 8 inches long (fig. 957) ; the spud 2 inches long, 24 inches wide at the top, narrowing gradually to 2 inches at the bottom, the lower angles slightly rounded. It should be sufficiently strong to resist considerable force in digging out plants from the crevices of rocks. The iron portion, which unites the spud to the handle, should be par- ticularly attended to in this respect. This spade is put into a leather sheath, and fastened by a strap round the waist, the spade itself being 796 COLLECTING AND DRYING OF PLANTS. attached to the strap by a long string. A japanned tin box or Vaseu- lum is required for the reception of specimens. This should be of sufficient length to receive a plant of the full size of the herbarium paper ; it ought to be convex on both sides (fig. 958) ; and its capacity Fig. 957. Fig. 959. may vary according to the wish of the collector. In long excursions where productive localities are visited, it will be found that a vasculum 20 inches long, by 8 or 9 inches wide, and 5 deep, is not too large; and when it is made of thin tin it is by no means heavy. At one end a good sized thickish handle should be placed, and it is necessary to have wires fixed at each end (a) so as to receive a strap for fastening the vasculum on the shoulders, The lid of the vasculum should be large, and is best secured by a wire which slips into a tin sheath, and so constructed as not to be liable to slip out when the box is held by the handle. The specimens should be put into the box in a uniform manner—the flower at one end, and the roots at the other; and care should be taken to have the former (which should be the end where the handle is) always kept on the higher position when carried on the shoulders. For mosses and some Alpine species of plants, a small box Fig, 960, may also be carried in the pocket. In col- lecting. minute aquatic plants, as Des- midiez and Diatomaces, it is necessary to have small glass bottles, or test tubes, fitted in a small case. The corks should be num- bered to facilitate notes being taken at the time of the locali- Fig. 957. Form of spade or digger. Fig. 958. Form of Vasculum or botanical box. Fig. 959. Form of Field-book for drying specimens of plants. Fig. 960. Small field-book with thin mahogany boards outside, which are brought together by leather straps, DRYING PAPER AND BOARDS. 797 ties in which the specimens were collected. Many plants will not bear transport ; their flowers fall off easily, and they are so delicate that their foliage becomes shrivelled. This is the case with the flower of Trientalis europea, Rubus Chamemorus, and Veronica saxatilis, and with some delicate Ferns. In such instances it is best to put them at once into paper. This is managed by having a small Field- book (fig. 959), which may be put into the pocket or suspended round the neck, secured by straps, so as to give pressure, and with an oil- cloth covering which may be used in wet weather. This field-book may be made with two thin mahogany boards on the outside. A convenient field-book, used by students in Edinburgh, is repre- sented by fig. 960. It is made of two mahogany boards, about nine inches long by five broad, containing from 12 to 24 parcels of paper, each parcel consisting of four sheets, the back of the parcels being covered with strips of leather or cloth. The boards may be rendered firm by being made each of two thin layers of crossed wood fastened together in the way afterwards noticed when speaking of large boards. Two narrow leather straps pass through two holes in one margin of each of the boards, and also through slits in the leather-covered backs of the parcels of the paper, a, so as to prevent them from falling out when the field-book is opened. In the case of one of the boards, the two straps also pass through perforations in its other margin, 6, and under these another strap is passed for the purpose of suspending the field-book round the neck. The two small straps pass through grooves in the margin of the other board, ¢, and are thus buckled so as to apply pressure. The Paper for drying should be moderately absorbent, 18 inches long by 11 broad, and arranged in parcels containing not less than four sheets. The paper which is generally used in Scotland is of consider- able thickness, absorbs moisture rapidly, but does not become too moist, and dries easily. A very thin kind of paper, called crown tea- paper, is used for holding very delicate plants, which cannot be easily transferred from one paper to another during drying. After being carefully laid out in the folds of this paper, they are placed between the sheets of drying paper, and when the paper is changed they are transferred at once in their thin cover without being disturbed. This. plan is useful in the case of such plants as Myriophyllum, Callitriche autumnalis, and other aquatics, as well as Viola lutea, whose petals collapse if removed i in the ordinary way, after a day’s pressure. In order that pressure may be given, Boards are requisite. These should be exactly the size of the drying paper. Some of them are used for outside boards, and these ought to be from 4 to } of an inch thick. Others are inside boards, about % of an inch thick. The out- side boards are often made double—each double board being composed of two thin ones, the grain of the one crossing that of the other (as in 798 BOTANICAL PRESS. the case”of the field-boards already mentioned), closely glued together, and firmly secured by small screws along the edge, at intervals of three inchés. ‘They may be rounded on their outer margins, For every two reams of drying paper not less than ten boards should be procured ; two of which are for the outside and eight for the inside. Sheets of stout pasteboard are also useful for packing up the plants as they become dry. The pressure is best applied, on a botanical excur- sion, by means of a rope put crosswise round the boards and paper, and tightened by a rack-pin. This is much better than straps, which are apt to give way, and are with difficulty replaced during an excur- sion. In other circumstances, pressure is best applied by means of heavy weiglits.-:4The pressure ought not to be less than 100 Ibs. This is preferable to a screw-press, in which the pressure is not kept up while the plants are losing their moisture. In order to allow free ventilation, and thus to dry plants more rapidly, Mr. Twining recom- mends, instead of boards, frames made of crossed bars, with spaces Fig. 961, E Fig. 962. between them ; the surface applied to the paper being flat,—the others being ribbed by means of prominent cross bars, so as to leave a venti- lating space between the one frame and the other (figs. 961 and 962). By an apparatus consisting of eight of such inner frames, and two outer frames of a stouter nature, so as to bear pressure, the plants as well as the paper may be dried rapidly. The apparatus, with paper and plants firmly strapped, is suspended in a draft of air coming through a partially closed window, or on the branch of a tree in sun- shine ; and it is said that desiccation of the plants and paper is accomplished in four days. By the use of artificial heat in an open and airy place, as, for instance, by being placed before the fire, the drying may be accomplished in twenty-four or forty-eight hours. Mr. Twining, when in Switzerland, first pressed the plants tightly for twenty-four hours, and then piled them properly in the frame-work apparatus, which was hung up in the hot air of a drying-room, and in twenty-four hours more they were ready for packing, the paper also Fig. 961. Frames formed of; cross-bars, for,pressure and ventilation. tFig. 962. Side view of frames. One of the frames, a, seen laterally, with its cross bars forming projections ; two of these frames, b and ¢, appear together, so as to‘allow ventilation between them. MODE OF DRYING PLANTS. 799 which contained them being perfectly dry and bibulous.* Henslow recommends that, with the view of ventilating plants during drying, holes should be made in the ordinary boards at regular intervals, and that two of the inner boards should always be placed together, sepa- tated by flat cross-bars, which may either be fastened to the boards by liquid glue prepared from shell lac, or may be kept loose, and in- serted when required. A complicated apparatus is suggested by M. Gannal, the particulars of which are given in the Botanical Gazette, ii. 55 ; and there also another mode of drying is described, in which plants, after having been kept in a press for a few hours, are exposed to the sun, or placed on astove or in an oven, in an apparatus called the Coquette. This consists of two open covers made of strong iron-wire network fastened into frames made of light iron rod, pressure being applied by straps or ropes, as already mentioned. The open frames allow the moisture to escape freely. Sheets of tin may be employed to separate the different layers of plants in process of drying, so as to hinder the humidity of one from reaching the other, or the inequalities of the larger from injuring the smaller and more delicate. In the case of plants with strong stems, they must either be split, or a sandbag, of the same size as the boards, used so as to equalise the pressure. Process or Dryinc.—The plants when collected are to be placed on the drying paper. In doing this a parcel of not less than four sheets is put on one of the outside boards; then the specimens are laid out carefully, preserving as far as possible their natural habits, and laying out the leaves and other parts. Another parcel of drying paper is then placed above these, and the same process is repeated with other speci- mens until twelve such parcels have been placed together. Then one of the inner boards is laid down, and other layers of paper and speci- mnens are applied, until the whole parcel is of sufficient size to be subjected to pressure. After twelve hours’ pressure, in most instances, the paper is changed, the moist paper being hung up to dry ; and in . transferring the specimens from the wet to the dry paper, a large pair of surgeon’s forceps is used. The interval elapsing between the changing of the paper may be increased or diminished according to the nature of the plants andthe state of the weather. In the course of eight or ten days, ordinary specimens will be so dry as to require only very slight pressure, with a moderate circulation of air. Some very dry plants, as grasses, may require only one changing. Succulent plants, such as Sedum and Sempervivum, continue to grow, however much submitted to pressure, and the ordinary methods of desiccation already indicated. In order to dry these plants completely and rapidly, it is necessary to kill them, by immersion in boiling water for five or ten minutes—some recommend the use of a solution of arsenic as a means of * See a description and drawing of this apparatus in Botanical Gazette, ii, 59. See also drawing of drying apparatus in Gardeners’ Chronicle, 1861, p. 76. 800 MODE OF DRYING PLANTS. killing them. The plants thus dealt with are then placed upon a cloth and left to drain for some time, after which they must be carefully placed between the folds of the drying paper, not forgetting to lay out properly any of the parts which the water may have disarranged. Orchideous plants are sometimes put into warm paper, and changed frequently, with the view, if possible, of preserving their colours by the rapidity of drying. Scarification has sometimes been adopted with the view of allowing the juice to flow out rapidly. Motley recom- mends that Orchids should be put into weak spirit for one or two nights, and then dried. In the case of some thick-headed plants, as Thistles, the capitula must either be cut, or they must be crushed between paper, by temporary pressure from the foot; this treatment must also be applied to such plants as Eryngium maritimum and the Holly. Sometimes the flower, or parts of the flower, may be separated advantageously during drying, by the insertion of small pieces of blotting-paper. At the time the specimens are laid out on the drying paper, a label should be inserted with the date of collecting, the name of the station, its elevation above the sea (if it can be ascertained), and any remarks as to soil or geological structure that may be known. In the course of long excursions, it is necessary to devote every now and then some time to the proper arranging and tallying of the speci- mens. On this subject Greville says, ‘ Half-a-day, therefore, at least, in the middle of the week, say the morning of every Wednesday, till two o’clock, should be appropriated to the preservation and arrange- ment of your plants ; anda part or the whole of every Saturday should invariably be set apart for the same purpose, in order that they may not be injured by remaining untouched on the Lord’s Day.” With the view of transporting dried plants securely in wet weather, it is useful to have a supply of oil-cloth to cover them. Mosses may be collected in excursions in tufts, and dried by mode- rate pressure at first. They can afterwards be separated, moistened, and dried with greater pressure. They ought to be gathered in fruc-. tification. In preserving minute Mosses, Dr. C. Miiller takes clear tale, splits it into thin layers, and cuts it into oblong pieces of proper size. Then, with a penknife, he splits one of these pieces, from one of the narrow sides, half-way through, so that it may be opened to admit the object and then close by its elasticity, the unsplit end serving as a holder. A drop of water is introduced into the slit with the object. When laid aside it dries, and may be rendered fit for microscopic examination by dipping in water. Lichens sometimes require to be taken with the rocks or stones to which they are attached, and they may be merely wrapped up in paper. Seaweeds must be washed with fresh water before being laid out. The more delicate kinds are floated out on pieces of stiff paper, and afterwards dried by moderate pressure. In preserving fungi, such as Agarics, SPECIMENS. FOR. HERBARIUM. 801 etc., a thin slice is taken from the centre, extending from the top of the pileus to the base of the stipe. This is dried separately to show the gills or pores, etc, The inner cellular portion of the pileus and stipe is then removed, and these parts are dried so as to give the form. Travellers visiting foreign countries (although not botan- ists) will find it an easy matter to preserve Mosses, Lichens, and Sea- weeds in a state fit for after-examination. In the case of Seaweeds, it is necessary to avoid such specimens as are in a state of decay. Those which are taken should be spread out in the shade to dry, without washing them with fresh water, and when quite dry, packed loosely in a box. Many species are found thrown upon the beach, and the pools in the rocks at low water are often filled with excellent specimens. The stems of the larger Algz are often covered with parasitic species, which should be dried without separation. When the specimens (whether Phanerogamous or Cryptogamous) are fully dried, they are then selected for the herbarium, and are fas- tened upon fine stiff paper, fit for writing upon, 17 inches by 104. In large herbaria, which are constantly consulted, the best way of securing the specimens is by means of fine thin glue ; the plants, after the glue is put on them, being made to adhere to the paper, by pres- sure between folds of drying paper. Some use gummed paper, others use thread or narrow ribbon, by means of which the specimens are sewed to the paper. Some put more than one species on a sheet. There may be as many specimens of the species as you choose, more especially from different localities. Put single specimens near one side of the herbarium sheet, and not in the middle; change the side on the alternate sheet. By this means one being on the right side of the sheet, another on the left, a third near the top, and a fourth near the bottom, the whole will be flat and not bulge up in the middle. Fasten any loose parts with the strips of gummed paper ; strap down the main stem in all cases, unless it is covered with hair, in which case strips are superfluous. Write the name of the plant near the lower right-hand corner of the half-sheet, and in some convenient spot near the specimen itself, the habitat, etc. If printed or written tickets are put on, let them be pasted (not glued) upon the lower right-hand corner. Plants of certain families, as Composite, are more particu- larly exposed to the ravages of insects. Hence, all plants after being dried should be brushed over with an alcoholic solution of corrosive sublimate.* This treatment has the inconvenience of discolouring * The solutions recommended are :— I. Methylated spirit . ‘ es z 1 gallon. Corrosive sublimate .. % 3 oe 4 02. Carbolic acid é “ A 2h : 4 02. or Il. Rectified spirit of wine a . : . . 16 fluid oz. Corrosive sublimate. ji 6 . 7 7 6 drachms. Creasote ey Les i : . 40 drops. 3F 802 CASES FOR HERBARIUM. them more or less completely, and making them assume a light brown tint ; but there can be no hesitation between the alteration of their colour and the complete destruction with which they are menaced, if not submitted to the above manipulation ; some recommend cyanide of potassium to destroy insects. In herbarium-presses camphor is em- ployed to prevent the attack of insects, The specimens must be kept dry, and frequently examined, and when insects are present, they must be retouched with the solution already indicated. Dry fruits, specimens of wood and bark, large roots, lichens and minute Algze on rocks or stones, or other specimens which cannot be preserved in a herbarium, may be either placed in drawers, in glazed cases, or in glass jars. The size of the wooden case for the herbarium must of course de- pend on the extent of the collection, In a private collection it is better to have numerous small cases, which are easily removed at pleasure along with the specimens. This should be particularly at- tended to by medical students, and others, who have the prospect of going abroad, and who may wish to transport their collections to foreign countries. In such instances the cases should be strongly made, and should be not more than four feet high, with two rows of drawers. These drawers are made open in front, and should slide freely in the case. In the Edinburgh University Herbarium, the size of the drawers or trays is—depth (inside measurement) 4 inches, length 19 inches, and breadth 114 inches. The size of the trays should of course correspond to that of the herbarium paper. Some collectors have peculiar fancies in regard to the size of their herbarium. Thus a valuable collection of Cryptogamic plants, grasses, sedges, rushes, etc., left by Menzies to the Edinburgh Botanic Garden has the fol- lowing dimensions :—Height of the mahogany cases 30 inches, breadth in front 284, from front to back 11; depth of the trays (inside mea- surement) 44 inches, length 94, breadth 6. SpecIMENS In A Moist Stare.—In preserving fresh specimens of fruits, and the other parts of plants, the best mode is to put them into a saturated solution of salt and water. They can thus be sent home from foreign countries in jars or barrels. In making a museum of such specimens, they are put into glass jars, the sizes of which should be regular—4, 8, 12, and 16 inches high, with a diameter varying according to the size of the specimen. The glasses may be filled with the following solution, which is nearly the same as that used by Goadby, and which seems to answer well in most instances :— Bay salt . F . 3 7 7 : ‘ 4 ounces, Burnt alum . ; ‘ . ‘ ‘ ; d 2 ounces. Corrosive sublimate 5 5 : 7 ‘ . 5-10 grains. Boiling water z : : : ‘ : 5 2 quarts. SPECIMENS IN A MOIST STATE. 803 Dissolve and filter the solution. Alcohol is often used, but it usually makes all colours alike brown. It is useful for delicate specimens which are required for dissection. Pyroligneous acetic acid diluted with from 3 to 5 parts of water is also very generally employed. Specimens, however, in the acid are apt to become pulpy and brittle after a few years, so as not to admit of being handled ; most colours are altered by it. Before being put in jars, fresh specimens should be kept for a month or more in the solution, so as to allow any colouring matter and other impuri- ties to be separated, otherwise the preparation will become obscure, and require to be re-adjusted. The mouth of the glass jars may be conveniently covered with India rubber, or, in the case of glasses of small diameter, with a watch glass secured by sealing wax, or by circular glass covers cemented by a lute com- posed of resin 1 part, wax 2 parts, and vermilion 1 part. The glass cover on the top of the jar may be either luted or held in its place by a metallic ring (fig. 963 a), which is fitted carefully to it, and covers a portion of the glass lid. Two grooves may be made on the inner side of the rim at the top of the jar for holding a piece of whalebone, to which the specimen may be attached by means of a thread, as seen in the figure. In the case of dry preparations, the metallic ring answers well. It is difficult to keep the solution of salt in the preparation jar. Sir Robert Christison says :—“ The most effectual method, when the mouth of the jar does not exceed 2 or 24 inches in diameter, is to have a space half-an-inch or more at the top of the fluid, to clean and dry the top of the jar thoroughly, to drop melted sealing-wax on the upper surface of the top, so as to form a uniform ring over it, to place over the mouth a watch-glass of such size as to cover the whole lip, and even to overhang it a little, to press this gently down with one finger, and to fuse the wax between the top of the jar and the watch-glass, by moving a large spirit flame around the edge.” Where the mouth of the jar is large, then a round flat piece of glass may be used, or sheet caoutchouc. The latter, after being gently heated, is stretched moderately, not strongly, by one, or still better, by two persons, while a third secures round the neck two or three folds of stout twine as a temporary ligature. A stout thin cord is then drawn steadily and tightly round three or four times above the former, taking care that the caoutchouc is not cut, and that the turns of the twine lie regularly above each other ; and finally, that a secure knot is made, Fig. 963. Jar for holding wet or dry preparations, the glass cover at the top being held in its place by a metallic ring. 804 HINTS AS TO ALPINE TRAVELLING. . SEEDS, when sent from abroad, should be collected perfectly ripe and dry, and if possible kept in their entire seed-vessels. Small seeds may be folded in cartridge paper, and should be kept in a cool and airy place during transport. Large seeds and oily seeds, which lose their germinating power speedily, are best transported in earth. A box about 10 inches square, with the sides ? of an inch thick, answers well. In this may be put alternate layers of earth and seeds, the whole being pressed firmly together. Living plants are best trans- ported in Wardian cases, and seeds or fruits may also be scattered in the earth of the cases. Bulbs and rhizomes not in a state of vegeta- tion, cuttings of succulent plants, as aloes and cactuses, and the pseudo- bulbs of Orchideous plants, may be put into a box or barrel with dry moss, sand, peat, or sawdust. Hints as to the Preparations to be made for Alpine Travelling, particu- larly in Switzerland, partly taken from. Will’ “Wanderings on the High Alps,” A botanical trip for six weeks in Switzerland, including the expense of going and coming, need not cost more than twelve shillings a-day. In a pedestrian tour the traveller must be as lightly equipped as possible ; at the same time he must so provide as to have a change of dress in case of wet weather. The Botanist must send his heavy portmanteau and his drying paper, with boards, ropes, and rack-pin, to different points by railway or post. During his alpine rambles he will find that he can only carry his box, spade, field-book, alpenstock, and light waterproof. His knapsack, while he is botanising, must be carried by a porter. He should, however, be prepared on an emergency to carry all his alpine baggage with him, more especially when passing from one station to another by some beaten track, where few plants are to be expected. A large party will find it convenient and economical to hire a horse for the conveyance of their knapsacks. The articles required are as follows :— A light waterproof knapsack, which will bear rough usage, about 14 inches long, 10 inches broad, and 34 inches deep, with two light straps at the top to hold a very light waterproof, and a stout leather handle by which to carry it, if necessary. The straps for the shoulders should be broad. One of the shoulder straps should end in a ring, and a hook should be fastened on the lower edge of the knapsack to receive it. By this contrivance the knapsack is easily taken off. The whole apparatus ought not to weigh above 2 Ibs. Good shoes, large, so as to allow for the swelling of the feet, the soles from 3ths to #ths of an inch thick, studded with stout nails, not too thickly. They should be worn with gaiters, so as to keep out dust, stones, etc, HINTS AS TO ALPINE TRAVELLING. 805 Soft woollen socks, such as those made in Shetland. Of these two or three pairs are required. A shooting coat, a waistcoat, and trousers of flannel, or of shepherd’s plaid, the two former being double-breasted. Flannel should always be worn next the skin on account of rapid changes of temperature on the glaciers and in the valleys. A light wide-awake hat, with strings or elastic band. In very hot weather the action of the sun on the forehead and temples may be diminished by a thick roll of white muslin round the hat. A light waterproof of silk; one may be got weighing only six ounces, The contents of the knapsack should not weigh more than 6 or 7 Ibs. They should consist of two spare thin merino shirts, three or four pairs of socks, well run in heels and toes, a very thin pair of trousers or drawers for change, two pocket handkerchiefs, and a pair of light shoes; materials for mending—as needles, thread, worsted, tape, buttons, bits of cloth and flannel ; also string, soap, sponge, brush and comb, and tooth-brush ; oiled-silk, lint, and bandages ; ordinary medicine—as compound rhubarb pills, opium, and sugar of lead and opium pills, tartar emetic, lard and sticking-plaster ; a small quantity of note-paper, ink, and pens; a large knife, furnished with a corkscrew, gimlet, and saw; lucifers; a pair of dark spectacles, and a dark veil, and warm gloves and muffitees. There may be also added a journal, a thermometer, compass, clinometer, whistle, and a small telescope. A flask and drinking-cup will also be of service, and a common coarse blouse, which can be procured in Switzerland for two francs. For travelling on glaciers a few screws, about $ths of an inch long, with large double-pointed heads, are useful. Wills procured them at Chamouni. These are screwed into the sole, three or four being enough for each shoe. For glacier work, stout ropes, thicker than a window-sash cord are required, 10 to 15 feet for each person, and an ice hatchet. An alpenstock, 6 feet in length, is of essential service. A good map is also of great value. The botanist must also have a small tin box, 10 or 12 inches in length, and about 4 deep; a small spade, in a leathern case, fastened round his waist, and a small field-book for drying plants,-made of thin wooden boards, 8 or 9 inches long, and about 5 inches broad, and containing drying paper, about 1 or 14 inch deep. The plants gathered must be transferred to larger drying paper at different stations, and must then either be carried by a porter, or sent by conveyance of some sort. It is by no means necessary to have guides in every part of the Alps of Switzerland. For instance, Mr, Wills says, that none are required for the Col de Balme, the Téte Noire, the Col de Vose, the Great St. Bernard, the Gemmi, and the Grimsel. In wandering, 806 DIRECTIONS TO COLLECTORS however, among the high mountains, it is always safe to take a guide. Wills suggests that the best way is to secure a good guide at starting, and keep him during the whole tour. He costs about five or six francs a day. Directions to Collectors visiting Foreign Countries, condensed from Hooker’s Kew Miscellany, Vol. IX., pp. 214-219. A Botanist visiting a foreign country should make as perfect a collection as possible of all the plants, neglecting no species, and pre- serving specimens of every kind, more especially such as seem to be confined to certain localities. The arborescent plants, trees of every description, are to be sought for and collected in flower and in fruit ; cones and larger acorns, and other kinds too large for the hortus siccus, are to be preserved apart from the foliage, and notes made of the locality, height, bulk of the trunk, etc. In proportion as mountains are ascended, the vegetation will be found to change, and to become more interesting and more peculiar. Particular notice should be taken of the heights at which different plants grow, and of those plants which are found nearest to the limit of perpetual snow. Care should be taken to preserve the collections from wet and damp. They may require to be opened occasionally, and exposed to a dry air or artificial heat. Seeds should be collected, and transported in the way already noticed. Objects of interest as regards economic botany should be collected ; such as articles of food, clothing, ornament, medicines, resins, dye-stuffs, samples of woods, particularly those good for carpentry and cabinet work. Varieties and abnormal forms of species should be sought for and preserved, attention being paid to differences in habit, and in the form of leaves and flowers in the same species at different periods of growth and in different conditions of growth. A comparison should be instituted between the flowers of different regions, as of the plains, swamps, and of different heights and exposures on the moun- tains, as well of different geological districts, as granite, limestone, etc. The times of leafing and flowering of bushes and trees, etc., should be noticed. When the vegetation seems unusually retarded or accelerated, the temperature of the surface soil and at three feet deep should be _ ascertained, wherever possible. The collector should, as soon as pos- sible, make himself acquainted with the names of the more common and conspicuous plants of the district he traverses, by consulting any works which may have been written regarding it. The plants which affect waysides or the tracks of man and animals should be noticed, and the effect of clearing away forests and of burning grass land on the subsequent vegetation should be attended to. The transport of seeds by man and animals is a subject of great interest, which should not be neglected. Care should be taken to ticket the specimens, so IN FOREIGN COUNTRIES. 807 that there may be no difficulty in determining their localities after- wards. Notes as to elevation (if above 2000 feet of the sea level), dates, name of district, and any other information, should be attached to the specimens to which they refer. A collector cannot be too care- ful in regard to these matters, Ascertaining the temperature of the trunks of evergreen and deciduous trees, and of the soil at their roots, is a subject of importance, The temperature of the soil at various depths during winter should be recorded ; also the temperature of the air and water between the under surface of melting snow-beds and the subjacent dormant vegetation, with the view of determining the causes of the rapidity with which plants germinate and blossom after the disappearance of snow from alpine situations,* * For fuller details, see instructions by Sir Wm. Hooker and Dr. Hooker, in Kew Miscel- luny, vol, ix. pp. 214-219. GLOSSARY OR EXPLANATION OF SOME OF THE TERMS USED ‘IN BOTANICAL WORKS. —~+— A, alpha, privative of the Greek, placed before a Greek or Latin word, indicates the absence of the organ; thus, aphydlus, leafless, acaulis, stemless. ABAXIAL or ABAXILE, not in the axis, applied to the embryo when out of the axis of the seed. ABIOGENESIS, same as HETEROGENESIS, aname for so-called spontaneous generation from in- organic matter. ABNORMAL, deviating from regularity or from the usual form of structure. ABORTION, suppression of an organ, depending on non-development. ABpRupT, ending in an abrupt manner, as the truncated leaf of the Tulip tree ; abruptly-pin- nate, ending in 2 pinnae, in other words, pari- innate ; abruptly-acuminate, a leaf with a broad extremity from which a point arises. ABSCISSION, cutting off, applied to the separa- tion of the segments or frustules of Diatoms. ACAULIS or ACAULESCENT, without an evident stem. ACCRESCENT, when parts continue to grow and increase after flowering, as the calyx of Phy- salis, and the styles of Anemone Pulsatilla. AccrETE, grown together. ; AccuMBENT, applied to the embryo of Cruciferz, when the cotyledons have their edges applied to the folded radicle. 2 ACEROSE, narrow and slender, with a sharp point. ; ACHENE or ACHNIUM, a monospermal seed- vessel which does not open, but the pericarp of which is separable from the seed. ACHLAMYDEOUS, having no floral envelope. ACHROMATIC, applied to lenses which prevent ‘chromatic aberration, z.e. show objects with- out any prismatic colours, AcIcULAR, like a needle in form. AcIcuLus, a strong bristle. : AcINaAciIFoRM, shaped like a sabre or scimitar. Acrnus, one of the pulpy drupels forming the fruit of the Raspberry or Bramble. AcTINENCHYMA, Cellular tissue, having a star- like or stellate form. AcoTYLEDONOUS, having no cotyledons. Acrocarrl, Mosses having their fructification terminating the axis. ACROGEN and AcROGENOUS, increasing at the summit, applied to the stems of ferns, which have a vascular cylinder penetrated by bundles of vessels belonging to the fronds ; and stems marked by the scars of the fronds. ACULEUS, a prickle, a process of the bark (not of the wood), as in the Rose; Acudeate, furnished with prickles. ACUMINATE, drawn out into a long point. ACUTE, terminating gradually in a sharp point. ADELPHOUS or ADELPHIA, in composition, means union of filaments. ADHERENT, united, adhesion of parts that are normally separate and in different verticils, as when the calyx is united to the ovary. ADNATE, when an organ is united to another throughout its whole length, as the stipules in sie and the filament and anther in Ranun- culus. ADPRESSED or APPRESSED, closely applied to a surface, as some hairs. ApuNcus, crooked or hooked. ADVENTITIOUS, organs produced in abnormal positions, as roots arising from aerial stems. FESTIVAL, produced in summer. ESTIVATION, the arrangement of the parts of the flower in the flower-bud. AFFINITY, relation in all essential organs. Acamous, the same as Cryptogamous. ALA, a wing, applied to the lateral petals of a papilionaceous flower, and to membranous appendages of the fruit, as in the Elm, or of the seed, as in pines. -ALBuMEN, the nutritious matter stored up with the embryo, called also Perisperm and Endo- sperm. ALBURNUM, the outer young wood of a Dicoty- ledonous stem. ALGOLoGy, the study of Seaweeds. ALSINACEOUS, a polypetalous corolla, in which there are intervals between the petals, as in Chickweed. ALTERNATE, arranged at different heights on the same axis, as when each leaf is separated by internodes from those next to it. ALVEOL&, regular cavities on a surface, as in the receptacle of the Sunflower, and in that of Nelumbium which is called 4 /veolate. 810 AMENTUM, a catkin or deciduous unisexual spike ; plants having catkins are A menti- Serous. Amnios, the fluid or semi-fluid matter in the embryo-sac. AMORPHOUS, without definite form. AMPHISARCA, an indehiscent multilocular fruit with a hard exterior, and pulp round the seeds, as seen in the Baobab. AMPHITROPAL, an ovule curved on itself, with the hilum in the middle. AMPLEXICAUL, embracing the stem over a large part of its circumference. AmpuLta, a hollow leaf, as in Utricularia. ANALOGOUS, when a plant strikingly resembles one of another genus, so as to represent it. ANAsTomosIs, union of vessels; union of the al ramifications of the veins of a leaf. ANATROPAL or ANATROPOUS, an_ inverted ovule, the hilum and micropyle being near each other, and the chalaza at the opposite end ; raphe present. ANCEPS, two-edged. ANDRECIUM, the male organs of the flower. ANDROGYNOUS, male and female flowers on the same peduncle, as in some species of Carex. ANDROPHORE, a Stalk supporting the stamens, often formed by a union of the filaments. ANEMOPHILOUS, applied to plants fertilised by the agency of wind. ANER, male or stamen, in composition, Azdro and Androus. ANFRACTUOSE, wavy or sinuous, as the anthers of Cucurbitacez. ANGIENCHYMA, vascular tissue in general. ANGIOCARPOUS, applied to Lichens having fructification in cavities of the thallus and opening by a pore. ANGIOSPERMOUS, having seeds contained in a seed-vessel. Anciosporous, Cryptogamic plants having spores contained in a theca or sporangium. ANISOS, in composition, means unequal. ANISOSTEMONOUS, stamens not equal in number to the floral envelopes, nor a multiple of them. ANNOTINUS, a year old. ANNULUS, a ring, applied to the elastic rim sur- rounding the sporangia of some Ferns, also to a cellular rim on the stalk of the Mushroom, being the remains of the veil. ANTERIOR, same as znferior, when applied to the parts of the flower in their relation to the axis, part of a flower next the, bract or in front. ANTHELA, the cymose panicle of Juncacez. ANTHER, the part of the stamen containing pollen. ANTHERIDIUM, male organ in Cryptogamic plants, frequently containing moving fila- ments. ANTHEROZOA, moving filaments in an antheri- ium. ANTHESIS, the opening of the flower. ANTHOCARPOUS, applied to multiple, poly- gyneecial, or confluent fruits, formed by the ovaries of several flowers, ANTHoDIuUM, the capitulum or head of flowers of Composite plants. ANTHOPHORE, a stalk supporting the inner floral envelopes,and separating them from the calyx. ANTHOS, a flower, in composition, Azzho; in Latin, Flos, GLOSSARY. ANTHOTAXIS, the arrangement of the flowers on the axis. Anrticus, placed in front of a flower, as the li of Orchids ; Anthere Antica, anthers whic! open on the surface next the centre of the flower ; same as /utvorse. ANTITROPAL, applied to an embryo whose radicle is diametrically opposite to the hilum. APERISPERMIC, without separate albumen ; same as Exalbuminous. APETALOUS, without petals, in other words, monochlamydeous. APHYLLOUS, without leaves. APICAL, or APICILAR, at the apex ; often applied to parts connected with the ovary. APICULATE, having an apiculus. ApicuLus or APICULUM, a terminal soft point springing abruptly. APLANATIC, applied to lenses in which spheri- cal aberration is corrected. APOCARPOUS, ovary and fruit composed of nu- merous distinct carpels. ApopHysis, a swelling at the base of the theca in some Mosses. APpoTHEciuM, the rounded shield-like fructifica- tion of Lichens. APTEROUS, without wings. ARACHNOID, applied to fine hairs so entangled as to resemble a cobweb. ARCHE, in composition, means beginning. ARCHEGONIUM, the young female cellular organ in Cryptogamic plants. ARCHISPERMS, another name for gymnosperms, ARCUATE, curved in an arched manner like a ow. AREOLATE, divided into distinct angular spaces, or Aveola. ARILLUS and ARILLODE, an extra covering of the seed, the former proceeding from the placenta, as in Passion-flower, the latter from the exostome, as in the Mace of Nutmeg. ARISTA, an awn, a long-pointed process, as in Barley and many grasses, which are called Avistate, ARMATURE, the hairs, prickles, etc., covering an organ. ARTICULATED, jointed, separating easily and cleanly at some point. ASCENDING, applied to a procumbent: stem, which rises gradually from its base ; to ovules attached a little above the base of the ovary; and to hairs directed towards the upper part of their support. Ascrp1uM, a pitcher or folded leaf, as in Ne- penthes. Ascus, a bag, applied to the thecz of Lichens and other Cryptogams, containing sporidia or spores. ASPERITY, roughness, as on the leaves of Bora- ginaceze. M ATRACTENCHYMA, tissue composed of spindle- shaped cells. Arropous or ATROPAL, the same as Ortho- tropous. AuRICULATE, having appendages, applied to leaves having lobes op leaflets at their base. Awn and Awnep, see Avista and Aristate. AxiIL, the upper angle where the leaf joins the stem. AXILE or AxIAL, belonging to the axis. AXILLARY, arising from the axil of a leaf. Axis, is applied to the central portion of the GLOSSARY. young plant, whence the plumule and radicle are given off, and the name is given in general to the central organ bearing buds; in Grasses, the common stem of a locusta, Bacca, berry, a unilocular fruit, having a soft outer covering, and seeds immersed in pulp. All such fruits are called Baccaze. BacuLirorM, applied to rod-like bodies in the reproductive organs of Sphzroplea. Bavausta, the fruit of the Pomegranate. BarsaTe, BearDeD, having tufts of hair-like pubescence. Bark (cortex), the outer cellular and fibrous covering of the stem; separable from the wood in Dicotyledons. Barren, not fruitful, applied to male flowers, and to the non-fructifying fronds of ferns. Basat or Basivar, attached to the base of an organ. Basrprum, a cell bearing on its exterior one or more spores in some Fungi, which are hence called Basidtosporous. Bast or Bass, the inner fibrous bark of Di- cotyledonous trees. BATHYMETRICAL, measurement of depths at which plants grow in the ocean. BepeGuar, a hairy excrescence on the branches and leaves of Roses, caused by an attack of a Cynips. BIDENDATE, having two tooth-like processes. BIFARIOUS, in two rows, one on each side of an axis. : Birip, two-cleft, cut down to near the middle into two parts. BiroriNE, a raphidian cell with an opening at each end. BILAMELLAR, having two lamellz or flat divi- sions, as in some stigmas. Brirocutar, having two loculaments. BINATE, applied to a leaf composed of two - leaflets at the extremity of a petiole. Biocenesis, the production of living cells from previously existing cells of a similar nature. Brrearous, applied to cymose inflorescence when the first axis gives rise to two bracts, from each of which a second axis proceeds, and so on; thus the inflorescence is Dicho- tomous. BirarTITE, cut down to near the base into two arts, Buinwére, a compound leaf divided twice in a pinnate manner. BipPINNATIFID, a simple leaf, having lateral lobes with divisions extending to near the middle, the lobes being also similarly divided. BipPinNATIPARTITE, differing from bipinnatifid in the divisions extending to near the mid- rib. BipLicaATE, doubly folded in a transverse man- ner. BrrorosE, having two rounded openings. Bis, twice, in composition, Bz. BIsERRATE, or duplicate-serrate, when the serratures are themselves serrate. BrsEXuAL, male and female organs in the same flowers. BITERNATE, a compound leaf divided into three, and each division again divided into three. BITTEN, same as Premorse. 811 Brapg, the lamina or broad part of a leaf, as distinguished from the petiole or stalk. BLANCHING, see Ztiolation. BLeTTiInG, is the change of the pulp from green to brown, as occurs in the Medlar after being pulled and kept for some time; the fruit from being austere thus becomes soft and edible. Bote, the trunk of a tree. BoTHRENCHYMA, dotted or pitted vessels, with depressions on the inside of their walls. BRACHIATE, with decussate branches. Bract, a leaf more or less changed in form, from which a flower or flowers proceed ; flowers having bracts are called Bracteated. BRACTEOLE or BRACTLET, a small bract at the base of aseparate flower in a multifloral in- florescence. Bryotocy, the study of Mosses; same as Muscology. Bute, an underground bud covered with fleshy scales. Bu.sit or BULBLET, separable buds in the axil of leaves, as in some Lilies. BuLsous-BaSED, applied to hairs which are tumid at the base. © Bysso1p, very slender, like a cobweb. ees falling off very early, as calyx of Oppy. Casious, with a fine pale blue bloom. CasPITOSE, growing in tufts. CALATHIFORM, hemispherical or concave, like a bowl or cup. CaLATHIUM, same as Capitulum and Antho- dium. CALCAR, a spur, a projecting hollow or solid process from the base of an organ, as in the flowers of Larkspur and Snapdragon ; such flowers are called Calcarate or spurred. CALCEOLATE, slipper-like, applied to the hollow petals of some Orchids, also to the petals of Calceolaria. 5 CALLositTy or CALLUS, a leathery or hardened thickening on a limited portion of an organ. CALYCIFLOR#, a sub-class of Polypetalous Dicotyledons having the stamens attached to the calyx. Catycutus or CaLicutus, an outer calycine row of leaflets, giving rise to a double or calyculate calyx. CaryprTra, the outer covering of the sporangium of Mosses. CALYPTRIMORPHOUS, applied to pitchers or as- cidia having a distinct lid. Catyx, the outer envelope of the flower ; when there is only one envelope, it is the calyx. Camsium, mucilaginous cells between the bark and the young wood, or surrounding the vessels. CAMPANULATE, shaped like a bell, as the flower of Hare-bell. Z CAMPULITROPAL or CAMPYLOTROPAL, a curved ovule with the hilum, micropyle, and chalaza near each other ; no true raphe. CAMPYLOSPERM, seeds with folded laterally. 7 CANALICULATE, channelled, having a longi- tudinal groove or furrow. CANCELLATE, latticed, composed alone, or lattice-like cells. CaPILiary, filiform, thread-like or hair-like. the albumen of veins 812 CapPITaTE, pin-like, having a rounded summit, as some hairs. Caritu.uo ; head of flowers in Composite. CapREOLATE, having tendrils. CarRIFICATION, the ripening of the Fig, by means of the wild fig or Caprificus. Capsuta Crrcumscissa, same as Pyxis or Pyxidium. CapsuLe, a dry seed-vessel, opening by valves, teeth, pores, or a lid. CARCERULUS, a fruit consisting of several 1-2-: seeded indehiscent carpels cohering by a common style round a common axis; as a Mallow and Tropzolum. Carina, keel, the two partially united lower petals of papilionaceous flowers. CarINAL, applied to zstivation when the carina embraces the other parts of the flower. CarRNnosE, fleshy, applied to albumen having a fleshy consistence. Carpet or Carprpium, the leaf forming the pistil, Several carpels may enter into the composition of one pistil. , CARPOLOGY, the study of fruits. CaRPOPHORE, a stalk bearing the pistil, and raising it above the whorl of the stamens, as in Lychnis and Capparis. Carros, fruit, in composition Carpo. CaRUNCULA, a fleshy or thickened appendage of the seed. Caryopsis or Carropsis, the monospermal seed-vessel of Grasses, the pericarp being incorporated with the seed. CassIDEous, shaped like a helmet. CaTKIN, same as Amentum. CauDATE, having a tail or feathery appendage. CauDEx, the stem of Palms and of Tree-ferns. CauDIcLE, Caupicuta, the process supporting a pollen-mass in Orchids. CAULESCENT, having an evident stem. CAULICLE, CAULICULUS, a stalk connecting the axis of the embryo and the cotyledons. CauLis, an aerial stem. CELLULOsE, the chemical substance of which the cell-wall is composed. CENTIMETRE, a French measure, equal to 0.3937079 British inch. CENTRIFUGAL, applied to that kind of inflo- esscence in which the central flower opens rst. CENTRIPETAL, applied to that kind of inflores- cence in which the flowers at the circumfer- ence or base open first. CERAMIDIUM, an ovate conceptacle having a terminal opening, and with a tuft of spores arising from the base ; seen in Algze. CERATIUM, a siliqueeform capsule, in which'the lobes of the stigma are alternate with the placenta, as in Glaucium and Corydalis. CEREAL, applied to Wheat, Oats, Barley, and other grains. CeRrNvous, pendulous, nodding. Cuarry, covered with minute membranous scales. Cuavaza, the place where the nourishing vessels enter the nucleus of the ovule. CuLamys, covering, applied to the floral en- velope, in composition Chlamydeous. CHLOROPHYLL, the green colouring matter of leaves. CHLoROos, green, in composition Chloro. Cuorisis or CHORIZATION, separation of a GLOSSARY. lamina from one part of an organ, so as to form a scale or a doubling of the organ; it may be either transverse or collateral, | Caroma, colour, in composition, Chrom.” CuRomoGen and CHROMULE, the colouring matter of flowers. Curysos means yellow like gold, in composi- tion Chryso. CicaTRICULA, the scar left after the falling of a leaf; also applied to the hilum or base of the seed. Cixta (Cilium), short stiff hairs fringing the margin of a leaf; also delicate vibratile hairs of zoospores ; cz/iaze, with cilia. CinencHYMa, laticiferous tissue, formed by anastomosing vessels. CircinaTE, rolled up like a crozier, as the young fronds of Ferns. CIRCUMSCISSILE, cut round in a circular man- ner, such as seed-vessels opening by a lid. oe the periphery or margin of a leaf. Cirrus, a tendril, or modified leaf in the form of a twining process. CisToLITH, an agglomeration of raphides (Sphzraphides) suspended in a sac by a tube, as in Ficus elastica. : CLADENCHYMA, tissue composed of branching cells. : CLapocarprl, mosses producing sporangia on short lateral branches. CLanoprosis, the fall of branches as in Thuja, Taxodium, Glyptostrobus and Tamarisk. Crapos, a branch, in composition Clado. CLATHRATUS, latticed like a grating. CLavaTE, club-shaped, becoming gradually thicker towards the top. Caw, the narrow base of some petals, corre- sponding to the petiole of leaves. CLEFT, divided to about the middle. CLINANDRIuM, the part of the column of Orchids bearing the anther. CLINANTHIUM, the common receptacle of the flowers of Composite. Curve, a bed, in composition C/z, used in re- ference to parts on which the floral organs are inserted. Cioves, applied to ‘young bulbs, as in the mion. CLypEATE, having the shape of a buckler. Coccrpium, a rounded conceptacle in Algx without pores, and containing a tuft of spores, : Coccus and Coccum, applied to the portions composing the dry elastic fruit of Euphor- biacez. Cocuiear, a kind of zstivation, in which a helmet-shaped part covers all the others in the bud. CocHLEARIForRM, shaped like a spoon. Ca@LosPERM4, seeds with the albumen curved at the ends. ConerentT, cohesion of part in the same ver- ticil, as sepals, petals, or stamens. CoLEorRHIZzA, a sheath covering the radicles of a monocotyledonous embryo. COLLATERAL, placed Hae ue side, as in the case of some ovules. CoLLENCHYMA, the inter-cellular substance which unites cells. Co.tum, neck, the part where the plumule and radicle of the embryo unite, GLOSSARY. CoLrencuyma, tissue composed of wavy or sinuous cells. CoLuMELLA, central column in the sporangia of Mosses ; also applied to the carpophore of Umbelliferze. Cotumn, a part in the flower of an Orchid sup- porting the anthers and stigma, and formed by the union of the styles and filaments, Coma, applied variously to tufts of hairs, to bracts occurring beyond the inflorescence, and to the general arrangement of the leaf- bearing branches of a tree, etc. ‘ CommissurE, union of the faces of the two achenes in the fruit of Umbelliferz. Comose, furnished with hairs, as the seeds of the Willow. Compounb, composed of several parts, as a leaf formed by several separate leaflets, or a pistil formed by several carpels either sepa- rate or combined. CompPRESSED, flattened laterally or lengthwise. | CoNCEPTACLE, a hollow sac containing a tuft or cluster of spores. ConpbucTING Tissug, applied to the loose cellu- ie pase in the interior of the canal of the style. ConpupLicaTE, folded upon itself, applied to leaves and cotyledons, Cong, a dry multiple fruit, formed by bracts covering naked seeds. CoNENCHYMA, conical cells, as hairs. CONFERVOID, formed of a single row of cells, or having articulations like a Conferva. ConFLUENT, when parts unite together in the progress of growth. Conip1a, peculiar spores in Fungi, which re- semble buds. ConjuGaTE spirals, when whorled leaves are so arranged as to give two or more generat- ing spirals running parallel to each other; according to the number of leaves in the whorl, the spirals are bijugate, trijugate, quinquejugate, etc. ConjJuGaTION, union of two cells, so as to de- velop a spore. CoNNATE, when parts are united even in the early state of development; applied to two leaves united by their bases. Connective, the part which connects the an- ther lobes. ConNIVENT, when two organs, as petals, arch over so as to meet above. ConTORTED, when the parts in a bud are im- bricated and regularly twisted in one direc- tion. ConvoLuTE or CoNVOLUTIVE, when a leaf in the bud is rolled upon itself. CorALLINE, like Coral, as the root of Corallor- hiza. CorcuLum, a name for the embryo. Corp, the process which attaches the seed to the placenta. ‘ CorpDaTE, heart-shaped, a plane body with the division or broad part of the heart-next the stalk or stem. CorpiForM, a solid body having the shape of a heart. Coriaceous, having a leathery consistence. Corm, thickened underground stem, as in the Colchicum and Arum. CorMoGEN#, having a corm or stem. g Cornu, a horn ; Corneous, having the consist- 813 ence of horn; Bicornis or Bicornute, having two horns. CoRoL a, the inner envelope of the flower. CoroLiirLor#, Gamopetalous (Monopetalous) Exogens, with hypogynous stamens. Corona, a corolline appendage, as the crown of the Daffodil. CorRUGATED, wrinkled or shrivelled. CorTEx, the bark ; Cortical, belonging to the bark ; Corticated, having a bark. Cortina, the remains of the veil which con- tinue attached to the edges of the pileus in Agarics, Coryms, a raceme in which the lower stalks are longest, and all the flowers come nearl: to a level above ; Corymbiferous or Corymb- ose, bearing a corymb, or in the form of a corymb. CosTA, a rib, applied to the prominent bundles of vessels in the leaves; Costate, provided with ribs. CoTyLEDON and CoTyLEpons, the temporary leaf, leaves, or lobes, of the embryo ; insome cases the Cotyledons are persistent, as in Welwitschia. CRAMPONS, a name given to adventitious roots which serve as fulcra or supports, as in the vy: Cxamockny: the fruit of Umbelliferze, com- posed of two separable achenes or mericarps. CRENATE, having superficial rounded marginal divisions. CRENATURES, divisions of the margin of a cre- nate leaf. CREST, an appendage to fruits or seeds, having the form of a crest. . Crisp, having an undulated margin. CRowN oF THE Root, the short stem which is at the upper part of the root of perennial herbs. CruciForM and CrvuciATE, arranged like the parts of a cross, as flowers of Crucifer. Crustaceous, hard, thin, and brittle ; applied to those Lichens which are hard and expanded like a crust. CryPTOGAMOUS, organs of reproduction ob- scure. CryPTos, inconspicuous or concealed, in com- position Cryo. CucuL.aTE, formed like a hood. CuLM, stem or stalk of grasses. CuNEIFORM or CUNEATE, shaped like a wedge standing upon its point. Cuputa, the cup of the acorn, formed by aggregated bracts. CuRVEMBRYE&, plants with the embryo curved. Cusris, a long point large at the base, and gradually attenuated ; Cusfzdate, prolonged into a cuspis, abruptly acuminate. CuTIcLE, the thin layer that covers the epider- mis. CyaTuiForM, like a wine-glass; concave, in the form of a reversed cone. CycLocEns, applied to Dicotyledons with con- centric woody circles. Cyctosis, movement of the latex in laticiferous vessels. CYLINDRENCHYMA, tissue composed of cylind- rical cells. CymsiForm, shaped like a boat. Cyne, a kind of definite inflorescence, in which the flowersare in racemes, corymbs, or umbels, 814 the successive central flowers expanding first ; Cyzmose, inflorescence in the form of a cyme. CyNARRHODUM, fruit consisting of a hollow inferior receptacle containing numerous achenes, as in the Rose. CypsELa, inferior monospermal indehiscent fruit of Composite. Cysripia, sacs containing spores; a kind of fructification in Fungi. Cystocarp, the fully-formed fructification of Floridez, a tribe of Red Seaweeds. CysTo.itH, a cell, containing numerous crys- tals (raphides), as in leaf of Ficus. CyTos ast, the nucleus of a cell. CyToBLASTEMA, mucilaginous formative matter of cells, called also Protoplasm. CyToGENEsis, cell-development. Cytos, a cell, in composition Cyzo. DDALENCHYMA, entangled cells. Deca, ten, in Greek words, same as the Latin Decem ; as decandrous, having ten stamens ; decagynous, having ten styles. Decipvuous, falling off after performing its functions for a limited time, as calyx of Ranunculus. Decipuous Trees, which lose their leaves annually. Decimetre,‘the tenth part of a metre, or ten centimetres. DeciinaTE or DEcLINING, directed downwards from its base ; applied to stamens of Amarylhs. DeEcomMpounp, a leaf cut into numerous com- pound divisions. DEcoRTICATED, deprived of bark. DeEcuMBENT, lying flat along the ground, and rising from it at the apex. DecurreEnT, leaves which are attached along the side of a stem below their point of inser- tion. Such stems are often called Winged. DEcussaTE, opposite leaves crossing each other in pairs at right angles. DepupticaTIon, same as Chorisis. DerinitTe, applied to inflorescence when it ends ina single flower, and the expansion of the flower is centrifugal; also when the number of the parts of an organ is limited, as when the stamens are under twenty. DEFLEXED, bent downwards in a continuous curve. DerouiaTion, the fall of the leaves. DEGENERATION, when an organ is changed from its usual appearance and becomes less highly developed, as when scales take the place of leaves. DEHISCENCE, mode of opening of an organ, as of the seed-vessel and anther. Detrotp, like the Greek A in form, properly applied solely to describe the transverse section of solids. DentaTE, toothed, having short triangular divisions of the margin. The term is also applied to the superficial divisions of a gamo- sepalous calyx and a gamopetalous corolla. DENTICULATE, finely-toothed, having small tooth-like projections along the margin. DeEprESSED, flattening of a solid organ from above downwards. DeETERMINATE, applied to definite or cymose inflorescence. Dextrorss, directed towards the right. GLOSSARY. DIACHANIUM, same as Cremocarf, fruit com- posed of two achenes. Diacuyma, the parenchyma of the leaf. DIADELPHOUS, Stamens in two bundles, united by their filaments. DiALycarpous, pistil or fruit composed of dis- tinct (separate) carpels. DIALYPETALOUS, corolla composed of separate petals. DIALYSEPALOUS or DIALYPHYLLOUS, calyx composed of separate sepals. DicHLAMYDEOUS, having calyx and corolla. DicHoGamous, stamens and stigmas of the same flower, not reaching maturity at the same time. DicuotTomous, stem dividing by twos, Dicuotomous Cymg, a kind of definite in- florescence in which the secondary axes come off in pairs, each ending in a single flower; the same kind of division goes on through the tertiary and quaternary axes, etc. Dicuinous, unisexual flowers, either monceci- ous or dicecious. Dineen) embryo having two cotyle- ons. DictyocEenous, applied to monocotyledons having netted veins. Dipymovs, twin, union of two similar organs. Dipynamous, two long and two short stamens. DiciTaTE, compound leaf composed of several leaflets attached to one point. Dicynous, having two styles. DILaMINATION, same as Deduplication and Chorists. Dimerous, composed of two pieces. DimipiaTE, split into two partially, as the calyptra of some Mosses ; or completely, as the lobes of the anther in Salvia. Dimorpuic, having two forms of flowers, differ- ing in size and development of the stamens and pistils, as in Primula and Linum. Dimorruous, when similar parts of a plant assume different forms. Dicecious, or Diorcous, staminiferous and pis- tilliferous flowers on separate plants. Diccious_y-H ERMAPHRODITE, hermaphrodite flowers having only one of the essential organs perfect in a flower. DipLEcoLoBe&, cotyledons twice folded trans- versely. Dievoos, double, in composition Dzplo. DipLoPeRIsTOMI, Mosses with a double peri- stome. DipLosTEmonous, having a double row of stamens, which are thus often double the number of the petals or sepals. DieLorecia, an inferior, dry, 1-many-celled seed-vessel, usually opening by valves or by pores, as in Campanula. Dirrerous, having two wings. Dis, twice in composition, Dz, same as Latin Bis or Bi; as disepalous, havin g two sepals, dispermous, two-seeded. Discirorm, and Discorp, in the form of a disc or flattened sphere ; discoid pith, divided in- to cavities by discs. Disco1b, also applied to the flosculous or tubu- lar flowers of Composite. Discs, the peculiar rounded and dotted mark- ings on coniferous wood. Disk, a part intervening between the stamens and the pistil in the form of scales, a ring, GLOSSARY. etc. ; it is connected with the receptacle or torus. DisPErmous, having two seeds. DIssEcTED, cut into a number of narrow divi- sions, DissEPIMENT, a division in the ovary; ¢7xe, when formed by edges of the carpels ; false, when formed otherwise. DIssILiENT, applied to fruit which bursts in an elastic manner. DisticHous, in two rows, on opposite sides of a stem. DIsTRACTILE, separating two parts to a dis- tance from each other. DiTHECAL, having two loculaments. DivaricaTING, branches coming off from the stem at a very wide or obtuse angle. Dopveca, twelve; in Latin, Duodecim. Dopecacynous, having twelve pistils. DopEcaNnpDRous, having twelve stamens. DoLasriForM, shaped like an axe. Dorsat, applied to the suture of the carpel which is farthest from the axis. DorsiFERous, applied to Ferns bearing fructi- fication on the back of their fronds. Dorsum, the back, the part of the carpel which is farthest from the axis. DovusLe FLower, when the organs of repro- duction are converted into petals. Drups, a fleshy fruit like the cherry, having a stony endocarp. Drufels, small drupesaggre- gated to form a fruit, as in the Raspberry. Dumoss, having a low shrubby aspect. Duramen, heart-wood of Dicotyledonous trees. Dynamis, power, in composition means supe- riority in length ; as didywamtous, two stamens longer than two others. E or Ex, in composition corresponds to alpha, privative ; as ebracteated, without bracts ; exaristate, without awns ; edentate, without teeth ; ecostate, without ribs. EcuHINATE, covered with straight slender prickles, like an Echinus. EvatTers, spiral fibres in the spore-cases of Hepatic. : Exureticat, having the form of an ellipse. EMARGINATE, with a superficial portion taken out of the end. 7 Emprvo, the young plant contained in the seed. Empryo-sups, nodules in the bark of the beech and other trees. : EmprvocGEny, the development of the embryo in the ovule. . Empryococy, the study of the formation of the embryo. Empryo-sAc or EMBRYONARY-SAC, the cellular bag in which the embryo is formed. EMBRYOTEGA, a process raised from the sper- moderm by the embryo of some seeds during germination, as inthe Bean. : Enpeca, in Greek, eleven ; in Latin, Undecim. Enpecacynous, having eleven pistils. EnpeEcanprous, having eleven stamens. Enpocar?, the inner layer of the pericarp next the seed. . EnpocuromgE, the colouring matter of cellular plants. . ENDOGEN, an inward grower, having an endo- genous stem. : . nf Enpon, within or inwards, in composition Endo. : 815 EnpoPHiLeoum, the inner bark or liber. Enpopteura, the inner covering of the seed. ENDORHIZAL, numerous rootlets arising from a common radicle, and passing through sheaths, as in endogenous germination. ENDOSMOSE, movement of fluids inwards through a membrane. Enposrerm, albumen formed within the em- bryo-sac. Enposporous, Fungi having their spores con- tained in a case. Enpostomg, the inner foramen of the ovule. ENpDoTHEciuM, the inner coat of the anther. ENERVIS, without veins. EnnEA, nine; in Latin, Novem.” Ennegacynous, having nine pistils. ENNEANDROUS, having nine stamens. EnsirorM, in the form of a sword, as the leaves of Iris. ENTIRE (zzteger), without marginal divisions ; (tntegerrimus), without either lobes or mar- ginal divisions. Envevores, FLorAt, the calyx and corolla. Epi, upon, in composition means on the outside or above, as eficarp, the outer covering of the fruit ; epigynous, above the ovary. EpisastT, an abortive organ in the Oat, sup- posed to be the rudiment of a second coty- ledon. EPICALYx, outer calyx, formed either of sepals or bracts, as in Mallow and Potentilla. Epicarp, the outer covering of the fruit. EpIicuILiuM, the label or terminal portion of the strangulated or articulated lip (labellum) of Orchids. EpiIcOROLLINE, inserted upon the corolla. EpipermIs, the cellular layer covering the ex- ternal surface of plants. EPIGEAL, above ground, applied to cotyledons. Epicone, the cellular layer which covers the young sporangium in Mosses and Hepatice. Epicynous, above the ovary, and attached to it. EPIPETALOUS, inserted upon the petals. EpipHRaGcM, the membrane closing the orifice of the thecze of some Mosses, as Polytrichum. EPIPHYLLOUS, growing upon a leaf. EpipHyYTE, attached to another plant and grow- ing suspended in the air. EPIRRHEOLOGY, the influence of external agents on living plants. EpiIsPERM, the external covering of the seed. EpisporE, the outer covering of some spores. EQuiTANT, applied to leaves folded longitudi- nally, and overlapping each other without any involution. ERECT, applied to an ovule which rises from the base of the ovary ; also applied to innate anthers. Eros, irregularly toothed, as if gnawed. ERuMPENT, prominent, as if bursting through the epidermis, as seen in some tetraspores. Errio, the aggregate drupes forming the fruit of Rubus. EIOEATION, blanching, losing colour in the dark. EXALBUMINOUS, without a separate store of albumen or perisperm. EXANNULATE, without a ring, applied to some Ferns, as Botrychium and Ophioglossum. ExcEnTRIC, removed from the centre or axis ; applied to a lateral embryo. 816 Exciru.us, a receptacle containing fructifica- tion in Lichens. EXcuRRENT, running out beyond the edge or point. ExinTINE, one of the inner coverings of the pollen grain. Exo, in composition, on the outside. ExoGEn, outside grower, same as Dicotyledon. ExoruIZAL, radicle proceeding directly from the axis, and afterwards branching, as in Exogens. Exosmose, the passing outwards of a fluid through a membrane. Exosporous, Fungi, having naked spores. Exostome, the outer opening of the foramen of the ovule. ExoTHEc1uM, the outer coat of the anther. EXSERTED, extending beyond an organ, as stamens beyond the corolla. EXsTIPULATE, without stipules. ExTInNE, the outer covering of the pollen-grain. EXTRA-AXILLARY, removed from the axil of the leaf, as in the case of some buds. ExTrorsE, applied to anthers which dehisce on the side farthest removed from the pistil. ExvTiveE, applied by Miers to seeds wanting the usual integumentary covering, as in Olacacez. FALCATE or FatcirorM, bent like a sickle. Fase AXxEs OF INFLORESCENCE, an elongated axis produced by the union of several single- flowered axes, which are joined together by their extremities. FARINACEOUS, mealy, containing much starch. FASCIATION, union of branches of stems, so as to present a flattened riband-like form. FascicLe, a shortened umbellate cyme, as in some species of Dianthus. FastiGiATe, having a pyramidal form, from the branches being parallel and erect, as Lombardy Poplar. FaveLta, a kind of conceptacle in Algz. Fave .ip1a, spherical masses of spores, usually contained in sacs called capsules. FEATHER-VEINED, a leaf having the veins passing from the midrib at a more or less acute angle, and extending to the margin. FENESTRATE, applied to a replum or leaf with openings in it, compared to windows. FERTILE, applied to pistillate flowers; and to the fruit-bearing frond of Ferns. ee eer tissue, composed of spiral cells. Fisrous, composed of numerous fibres, as some roots. FIBRO-VASCULAR TISSUE, composed of vessels containing spiral and other fibres. Fip, in composition, cleft, cut down to about the middle. FitaMeEnt, stalk supporting the anther. He SOUS a string of cells placed end to end. Fitirorm, like a thread. FimpriATED, fringed at the margin. Fissiparous, dividing spontaneously into two parts by means of a septum. Fissure, a straight slit in an organ for the dis- charge of its contents. Fistutous, hollow, like the stem of Grasses. FLABELLIFORM, fan-shaped, as the leaves of some Palms. GLOSSARY. FLAGELLUM, a runner, a weak creeping stem bearing rooting buds at different points, as in the Strawberry. FLEXxvoSE or FLExvous, having alternate cur- vations in opposite directions ; bent in a zig- zag manner. FLocc1, woolly filaments with sporules in Fungi and Algz. FLoccose, covered with wool-like tufts. Fiorar Envecopres, the calyx and corolla. FLoscutous, the tubular florets of Composite. Fortation, the development of leaves. Fouiora, same as Phylla and Sepala. Fotticte, a fruit formed by a single carpel, de- hiscing by one suture, which is usually the ventral. Foor, French, equal to 1‘07892 foot British. ForameEn, the opening in the coverings of the ovule. FoveaTE or FovgoaTE, having pits or depres- sions called foveze or foveolz. FovitLa, minute granular matter in the pollen- rain. Fronp, the leaf-like organ of Ferns bearing the fructification ; also applied to the thallus of many Cryptogams. FRoNDosE, applied to Cryptogams with folia- ceous or leaf-like expansions. FrusTutes, the parts or fragments into which Diatomacez separate. FRuTEx, a shrub ; Fruticose, shrubby. Fucacious, evanescent, falling off early, as the petals of Cistus. Futvous, tawny-yellow. Funicutus, the umbilical cord connecting the hilum of the ovule to the placenta. FurcatTE, divided into two branches like a two- pronged fork. “ FuRFURACEOUS, scurfy or scaly. Fusirorm, shaped like a spindle. Ga.sutus, the polygyncecial confluent succu- lent fruit of Juniper. Ga.Ba, applied to a sepal or petal shaped like a helmet ; the part is called Gadeate. Gamo, in composition, means union of parts. GAMOPETALOUS, same as Jfonopetalous, petals united. GAMOPHYLLouSs and GAMOSEPALOUS, same as Monophylious and Monosepalous, sepals united. = GEMINATE, twin organs combined in pairs, same as Binate. Gemma, a leaf-bud ; Gemmation, the develop- ment of leaf-buds. GeEmMIFEROUS, bearing buds. GrEmMIPAROUS, reproduction by buds. GEMMULE, same as Plumule, the first bud of the embryo. GENICULATE, bent like a knee. GERMEN, a name for the ovary. GERMINAL VssICLE, a cell contained in the embryo sac, from which the embryo is de- veloped. Garros the sprouting of the young plant. GipposiTy, a swelling at the base of an organ, such as the calyx or corolla, as in Dielytra. Gissous, swollen at the base, or having a dis- tinct swelling at some part of the surface. GLaBRous, smooth, without hairs. GLAND, an organ of secretion consisting of cells, GLOSSARY. and generally occurring on the epidermis of plants. Gianputar Hairs, hairs tipped with a gland, as in Drosera and Chinese Primrose, Gans, nut, applied to the Acorn and Hazel- nut, which are enclosed in bracts. Graucous, covered with a pale-green bloom. GuosuLe, male organ of Chara. Gtocuip1aTE, barbed, applied to hairs with two reflexed points at their summit. GLOMERULUS, a rounded, cymose inflorescence, as in Urtica. Giossotoey, explanation of technical terms. Giumaczous, of the nature of glumes. Gung, a bract covering the organs of repro- duction in the spikelets of Grasses, which are hence called Glumiferous. GLUMELLE and GLUMELLULE, a name applied to the palea or fertile glume of a Grass. GonGYLI, same as Gonidia. Gonip1a, green germinating cells in the thallus of Lichens. Gonos and Gonz mean offspring; used in composition. Gonus or Gonu, in composition, means either ’ kneed or angled ; in the former case the a is short,.in the latter long : Polyginum, many- eed ; Tetragdnznz, four-angled. ; GRaIn, caryopsis, the fruit of Cereal Grasses. Sains of pollen, minute cells composing the pollen. GRANULES, minute bodies varying greatly in size, having a distinct external shadowed ring or margin, the external edge of which is abrupt. GRANULATED, composed of granules. Grumous, collected into granular masses. Gymnocarpous, Lichens having fructifications in the form of a scutellate, cup-shaped, or linear thallus. GyMNocEN, a plant with naked seeds, ze. seeds not in a true ovary. Gymnos, naked, in composition Gyzno. GyMNosPERMOUS, plants with naked seeds, z.e. seeds not in a true ovary, as Conifers. GymnosporE, a naked spore ; Gymnosporous, having naked spores. GymnosTomt1, naked-mouthed, Mosses without a peristome. GYNANDROPHORE, a column bearing stamens and pistil, GyYNANDRoUS, stamen and pistil united in.a common column, as in Orchids. Gynez, female, and Gyn, Gynous, and: Gyno, in composition, refer to the pistil or the ovary. b Gynizus, the position of the stigma on the column of Orchids. GynoBasg, a central axis, to the base of which the carpels are attached. Gynacium, the female organs of the flower. GynopuorE, a stalk supporting the ovary. GyNosTEGIuM, staminal crown of Asclepias. GynostTEmium, column in Orchids bearing the organs of reproduction. GyRATE, same as Circinate. _ GyraTion, same as Rotazion in cells. Hast of a plant, its general external appear- ance. : Hatopuy Tes, plants of salt marshes, contain- | ing salts of soda in their composition. 817 Hastate, halbert-shaped, applied to a leaf with two portions at the base projecting more or less completely at right angles to the blade. Hau.m, dead stems of herbs, as of the potato. Haustortum, the sucker at the extremity of the parasitic root of Dodder. Heap. See Capitulum. HEART-woop, same as Duramen. HEKISsTOTHERMS, plants requiring a very small amount of heat, as arctic and antarctic plants. HELIcoID cyme, in which the flowers are arranged in a continuous helix or spiral, ‘round a false axis. HE icoipat, having a coiled appearance like the shell of a snail, applied to inflorescence. Hemet, the upper petaloid sepal of Aconitum. Hemi, half; same as Latin Sew. 24% Hemicarr, one of the achenes forming the cre- mocarp of Umbelliferze. Hepra, seven ; same as Latin Septem. HeEpracynous, having seven styles. HeEpranprous, having seven stamens. Hers, a plant with an annual stem, opposed to a woody plant. HERBACEOUS, green succulent plants which die down to the ground in winter ; annual shoots ; green-coloured cellular parts. HERMAPHRODITE, stamens and pistil in the same flower. HEsperipium, the fruit of the Orange, and other Aurantiaceze. . HETERACMY, another name for Dichogamy. HETEROCEPHALOUS, composite plants having male and female capitula on the same plant. Hererocysts, peculiar cells forming large germs in Nostochinex, differing from spor- angia and spores. HETERODROMOUS, spirals running in opposite directions. HETERGcIuM, applied to potata fungus, meaning that part of its life is passed on some other host than the potato. HETEROGAMOUS, Composite having herma- phrodite and unisexual flowers on the same head. : HETEROGENESIS, another name for so-called spontaneous generation, in which living cells are supposed to be produced by inorganic matter. HETEROMoRPHIC, having different forms of flowers as regards stamens and pistils, and these forms being necessary for fertilisation, as in Primula. HETEROPHYLLOUS, presenting two different forms of leaves. HETERORHIZAL, rootlets proceeding from vari- ous points of a spore during germination. HETEROS, dissimilar or diverse ; in composition, Hetero. HETERosPorovs, Cryptogamic plants, having both microspores and macrospores on the same individual, as in Selaginella. HETEROTROPAL, ovule with the hilum in the middle, and the foramen and chalaza at op- posite ends. | HEXA, six ; same as Latin Sex. Hexacynous, having six styles. | HEXANDROUS, having six stamens. Hixum, the base of the seed to which the pla- centa is attached, either directly or by means of acord. The term is also applied to the mark at one end of some grains of starch. G 818 Hirsute, covered with long stiff hairs. Hisprp, covered with long very harsh hairs. HistoGenetic, applied to minute molecules, supposed to be concerned in the formation of cells. Hisrotocy, the study of microscopic tissues. Hotosericeous, covered with minute silky ees discovered better by the touch than by - sight. Homopromous, spirals running in the same direction. Homocamous, Composite plants having the flowers of the capitula all hermaphrodite. Homoceneous, having a uniform structure or substance. Homomorpuic, when the pistil is fertilised by the pollen from its own flowers ; this is self- fertilisation. 2 Homos and Homotos, similar, in composition Homo. Homortropat, when the slightly curved em- pee has the same general direction as the seed, Horotocicat, flowers opening and closing at certain hours, HoumIFusg, spreading along the ground. HYALINE, transparent or colourless ; applied by Barry to the part where the cell-nucleus appears. Hysrip, a plant resulting from the fecundation of one species by another. HyMeEniom, the part which bears the fructifica- tion in Agarics. 2 HypanTuopiuM, the receptacle of Dorstenia, bearing many flowers. Hypua, the filamentous tissue in the thallus of lichens. Hypuasma, a web-like thallus of Agarics. Hypo, under or below, in composition Hyg. Hypocarpocean, plants producing their fruit below ground. Hyrocuitium, the lower part of the labellum of Orchids. HypocraTerirorm, shaped like a salver, as the corolla of Primula. Hypocear or Hypocsous, under the surface of the soil, applied to cotyledons. Hee Nous inserted below the ovary or pistil. Hyrotuatvus, the mycelium of certain Ento- phytic Fungi, as Uredines. HyrsomeTRICAL, measurement of altitude. HysTerantuous, when leaves expand after the flowers have opened. HysTeropuyta, a name applied to Fungi. Icosanpria, having twenty stamens or more inserted on the calyx ; /cosandrous, having twenty stamens. Icos1, twenty; in composition JZcos. Latin Viginti. ImpRICATE or IMBRICATED, parts overlying each other like tiles on a house. Jsbricated @stivation, the parts of the flowér-bud alter- nately overlapping each other, and arranged in a spiral manner. Impari-PINNATE, unequally-pinnate, pinnate leaf ending in an odd leaflet. INARCHING, a mode of grafting by bending two growing plants towards each other, and caus- Same as ing a branch of the, one to unite to the |’ other. GLOSSARY. INARTICULATE, without joints or interruption to continuity. Incu, French, is equal to 1.06578 inch British. INcISED, cut down deeply. INCLUDED, applied to the stamens when enclosed within the corolla, and not pushed out beyond its tube. IncumBENT, cotyledons with the radicle on their back. INDEFINITE, applied to inflorescence with centri- petal expansion; also to stamens above twenty, and to ovules and seeds when very numerous. INDEHISCENT, not opening; having no regular line of suture. INDETERMINATE, applied to indefinite inflores- cence. Inp1GENovs, an aboriginal native in a country. INDUPLICATE or INDUPLICATIVE, edges:of the sepals or petals turned slightly inwards in estivation. Inpusium, epidermal covering of the fructifica- tion in some Ferns. Inpurive, applied by Miers to seeds having the usual integumentary covering. INERMIS, unarmed, without prickles or thorns. INFERIOR, applied to the ovary when it is situated below the calyx; and to the part of a flower farthest from the axis. INFLORESCENCE, the mode in which the flowers are arranged on the axis. INFUNDIBULIFORM, in shape like a funnel ; as seen in some gamopetalous corollas. INNATE, applied to anthers when attached to the top of the filament. Innovations, buds in Mosses. INTERCELLULAR SPACE, same as Lacuna, INTERFOLIAR, between two opposite leaves. INTERNODE, the portion of the stem between two nodes or leaf-buds. INTERPETIOLAR, between the petioles of op- posite leaves ; as the stipules of Cinchona. INTERRUPTEDLY-PINNATE, a pinnate leaf in which pairs of small pinnz occur between the larger pairs. INTERSTAMINAL, an organ placed between two stamens. INTEXTINE, one of the inner coverings of the pollen-grain. InTINE, the inner covering of the pollen-grain. INTRORSE, applied to anthers which open on the side next the pistil. INVERTED, applied to the embryo when the radicle points to the end of the seed opposite the hilum. InvoLucEL, bracts surrounding the partial umbel of Umbelliferze. INVOLUCRE, bracts surrounding the general umbel in Umbelliferze, the heads of flowers in Composite, and in general any verticillate bracts surrounding numerous flowers. It is also used in the same sense as the Indusium of Ferns. INVOLUTE or InvotuTIvE, edges of leaves rolled inwards spirally on each side, in esti- vation. IRREGULAR, a flower in which the parts of any of the verticils differ in size. : IsocHEIMAL or IsOcHEIMONAL, lines passing through places which have the same mean winter temperature. GLOSSARY. Isocuomous, branches springing from the same plant, and always at the same angle. ~ Isomeric, applied chemically to substances which, though differing in qualities, have the same elements in the same proportions. IsomErous, when the organs of a flower are composd each of an equal number of parts. Isos, equal, in composition /so. Isosporous, cryptogamic plants producing a single kind of spore, as ferns. IsosrEmonous; when stamens and floral enve- ope have the same number of parts or mul- tiples. IsoTHERAL, lines passing through places which have the same mean summer temperature. IsoTHERMAL, lines passing through places which have the same mean annual temperature. Jornincs, the places where the parts of the stem are attached to each other ; the nodes. Joints, spaces between the knots or nodes or joinings. Juca, a name given to the ribs on the fruit of Umbelliferze. Jucum, a pair of leaflets ; yugaze, applied to the | pairs of leaflets in compound leaves; unijugate, one pair ; bijugate, two pairs ; and so on, : KEEL, same as Carina. KLeEIsToGamous, applied to certain grasses in which fertilisation is effected in closed flowers. Kworttep, when a cylindrical stem is-swollen at intervals into knobs. LaseEL, the terminal division of the lip of the » flower in Orchids. LasBeELvu, lip, one of the divisions of the inner whorl of the flower of Orchids. This part is in reality superior as regards the axis, but becomes inferior by the twisting of the ovary. LasiaTe, lipped, applied to irregular gamo- petalous flowers, with an upper and under portion separated more or less by a hiatus or gap. LAcINIATED, irregularly cut into narrow seg- ments. Lacinuta, the small inflexed point of the petals of Umbelliferee. ‘ LacteEscEntT, yielding milky juice. Lacuna, a large space in the midst of a group of cells. Lavicatus, having a smooth polished appear- ance. Lavis, even. . . LaMELLA, gills of an Agaric, also applied to flat divisions of the stigma. » Lamina, the blade of the leaf, the broad part of a petal or sepal. LANCEOLATE, narrowly elliptical, tapering to each end. Lanucinous,. woolly, covered with long flexu- ous interlaced hairs. : LATERAL, arising from the side of the axis, not terminal. ; psi Larex, granular fluid contained in laticiferous vessels. 7 LaTIcIFEROUS, anastomosing vessels contain- ing latex. 7 LatiserT#, Cruciferous plants having a broad replum in their silicula, 819 Lecorropar, shaped like a horse-shoe, as some ovules. Lecumg, a pod composed of one carpel, open- ing usually by ventral and dorsal suture, as in Pea. LenTIcEL, a small process on the bark of the Willow and other plants, whence adventitious roots proceed. seu, in the form of a doubly-convex lens. LepipoTE, covered with scales or scurf; Zepis, a scale. Lianas or LIANEs, twining woody plants. Liper, the fibrous inner bark or endophloeum. LIEBERKUHN, a metallic mirror attached to the objective of a microscope for the purpose of throwing down light on opaque objects. LIGNINE, woody matter which thickens the cell-walls. Lisurane, strap-shaped florets, as in. Dande- 10n. LIGULE, a process arising from the petiole of grasses where it joins the blade. LicutirLor#, Composite plants having ligu- late florets. Limp, the blade of the leaf; the broad part of a petal or sepal; when sepals or petals are united, the combined broad parts are de- nominated collectively the limb. Ling, the r2th part of an inch; Linze, French, is equal to 0.088815 inch British. Lingzar, very narrow leaves, in which the length exceeds greatly the breadth. Lire Lia, sessile linear apothecium of Lichens, Lose, large division of a leaf or any other organ; applied often to the divisions of the anther. LocuticiDAL, fruit dehiscing through the back of the carpels. Locutus or LocuLaMENT, a cavity in an ovary, which is called zzzlocular when it has one cavity, dz/ocular with two, and so on. The terms are also applied to the anther. ‘Locusta, a spikelet of grasses formed of one or several flowers, Lopicuts, a scale at the base of the ovary of Grasses. Lomentum and LomENTACEovs, applied to a legume or pod with transverse partitions, each division containing one seed. LuNATE, crescent-shaped. LyrRaTE, a pinnatifid leaf with a large terminal lobe, and smaller ones as we approach the petiole. Macropopous, applied to the thickened radicle of a monocotyledonous embryo. Macros, large, in composition Macro. Macrosporanaia, cells or thece containing macrospores. Macrospores, large spores of Lycopods. MAacpicHiacgous Hairs, peltate hairs, such as are seen in’ Malpighiacez. ManicaTe, applied’ to scales surrounding a stalk like a frill, and easily removed. MaRCESCENT, withering, but not falling off until the part bearing it is perfected. MarGINnaTE, applied tocalyx, same as Obsolete. MASKED, same as Personate. Maru, a term sometimes used for crop; an agricultural term. 820 Marrutta, the fibrous matter covering the petioles of Palms. Mepuv ta, the cellular pith. Meputtary Rays or PLatss, cellular pro- longations uniting the pith and the bark. MeEpDuLtary SHEATH, sheath containing spiral vessels surrounding the pith in Exogens, MEGASPORANGIA, same as Macrosporangia. MEGATHERMS, or MACROTHERMS, plants re- quiring a high temperature. ARSE TINE, plants requiring extreme eat. MEIosTEMonous or MiosTEMoNoUS, the sta- mens less in number than ,the parts of the corolla. MeEmBrANACcEOUS or Mempranous, having the consistence, aspect, and structure of a membrane. Meniscus, a lens having a concave and a con- vex face, with a sharp edge. MS NEES tissue composed of rounded cells. Menricarp, single-seeded portion of a fruit composed of several monospermal carpels, which separate from each other when ripe ; as in Borage, Labiate, and Umbellifere ; also the separate monospermal portion of a Lomentum. MeriTHAL, a term used in place of internode; applied by Gaudichaud to the different parts of the leaf. Mesocarp, middle covering of the fruit. MEsocuILium, middle portion of the labellum of Orchids. MEsoPHLeuM, middle layer of the bark. MEsopHyL_um, the parenchyma of the leaf. Mesos, the middle, in composition Meso. MEsospPeERM, applied to a covering of the seed derived from the secundine. ENS) plants requiring a moderate eat, METASPERMS, another name for Angiosperms. METRE, equal to 39.37079 inches British. MIcRoMETER, instrument for measuring micro- scopic objects. wees the opening or foramen of the seed. Micros, small, in composition AZicro. Microsporancia, cells or thecz, containing microspores. : Microsporss, small spores of Lycopods, pro- ducing antheridia. MicroTHErms, plants requiring asmall amount of heat. MILLIMETRE, equal to 0.03937079 English inch, or 25.39954 millimetres equal to an English inch. Mirrirorm, shaped like a mitre, as the calyp- tra of some Mosses. Mo vecuce, an exceedingly minute body in which there is no obvious determinate ex- ternal circle or internal centre. MonabELpHous, stamens united into one bundle by union of their filaments, Monanprous, having one stamen. Monemsryony, having a single embryo. Moniu1Form, beaded, cells united, with inter- ruptions, so as to resemble a string of beads. Monocarric, producing flowers and fruit once during life, and then dying. MonocuLamypgous, flower having a single envelope, which is the calyx. GLOSSARY. Monoctinous, stamens and pistils in the same flower. MonocotTyLeponous, having one cotyledon in the embryo. : i Monczcious, or Monoicous, stamens and pis- tils in different flowers on the same plant. MonoGYNeciAL, applied to simple fruits, formed by the pistil of one flower. Monocynovs, having one pistil or carpel, also applied to plants having one style. MoNOPETALOUS, same as Gamopetalous. MonopuHyL.ous, same as Gamophyllous. Monos, one, in composition Mono and Mon, as Monandrous, one stamen; sometimes applied to the union of parts into one, as Monopetalous, meaning combined petals; same as Latin Unus. MownosEpa_ous, same as Gamosepalous. Monospermous or MonosPErMAL, having a single seed. MonoruEcat, having a single loculament. Monstrosity, an abnormal development, applied more especially to double flowers. MorpHo oey, the study of the forms which the different organs assume, and the laws that regulate their metamorphoses. Mucro, a stiff point abruptly terminating an organ; Mucronate, having a mucro, Mucus, definite, peculiar matter forming a covering of certain seaweeds. MUuLTICOSTATE, many-ribbed. MuttIF1p, applied to a simple leaf divided laterally to about the middle into numerous portions ; when the divisions extend deeper itis Multipartite. MuttTILocurar, having many loculaments. MouttTIPte, applied to anthocarpous or polygy- neecial fruits formed by the union of several flowers. MouricaTE, covered with firm, short points, or excrescences. ae ae like bricks in a wall; applied to cells. Muscotoey, the study of Mosses. Moticus, without any pointed process or awn. Myce ium, the cellular spawn of Fungi. NAKED, applied to seeds not contained”in a true ovary; also to, flowers without any floral envelopes. NaprirorM, shaped like a turnip. NATURALISED, originally introduced by arti- ficial means, but become apparently wild. Navicuvar, hollowed like a boat. NEcTARIFEROUS, having a honey-like secre- tion ; applied to petals having depressions or furrows at their base, which contain a sweet secretion. NEcTARY, any abnormal part of a flower. It ought to be restricted to organs secreting a honey-like matter, as in Crown Imperial. Nemea, from Nema, a thread, applied by Fries to cryptogams in allusion to the ger- mination by a protruded thread, without cotyledons. . NERVATION or NEURATION, same as Venation. NeETTED, applied to reticulated venation ; also covered with raised lines disposed like the threads of a net. Niripus, having a smooth and polished surface. Nong, the part of the stem from which a leaf- bud proceeds ; a joining. GLOSSARY. Noposs, having swollen nodes or articulations. Nopu ose, applied to roots with thickened knots at intervals. Nosovoey, vegetable, the study of the diseases of plants. NororuizeEs, radicle on the back of the coty- ledons, as in some Cruciferz. : Nuctegus, the body which gives origin to new cells ; also applied to the central cellular por- tion of the ovule and seed. Nucuxanium, applied to the fruit of the Med- lar having nucules; some also apply this term to the Grape. Noucute, hard carpel in the Medlar, also one of the parts of fructification in Characee. Nucumenrtaceous, Cruciferee having a dry monospermal fruit. Nout, properly applied to the glans, but also applied to any hard nut-like fruit, as in Carex and Rumex. Os, in composition, means reversed or con- trariwise. OxBcomprREssED, flattened in front and behind, not laterally. z OxscorDaTE, inversely heart-sHaped, with the divisions of the heart at the opposite end from the stalk. Os.ona, about # as long as broad; elliptical, obtuse at each end. OxovaTE, reversely ovate, the broad part .of the egg being uppermost. OsBsoLeTE, imperfectly developed or abortive : applied to the calyx when it is in the form of arim, Ostusg, not pointed, with a rounded or blunt termination. OsvoLuTE, margins of one leaf alternately overlapping those of the leaf opposite to it. Ocurea or OcrEa, boot, applied to the sheath- ing stipule of Polygonacez. Ocranprous, having eight stamens. Octo, eight, in composition Oct. Octocynous, having eight styles. Gcium and CEctous, in composition, have reference to the position of the reproductive |’ organs, as Axdracium, the staminal organs ; Diecious, stamen and pistil in different flowers. OFFICINAL, sold in the shops. OFFSET, same as Profagulum. OLERACEOUS, used as an esculent potherb. OLIGANDROUS, stamens under twenty. Ouicos, few or in small number ; in composi- tion OZigo and Olig. OvicosrERMmous, plant having few seeds. OMPHALODE, the central point of the hilum, where the nourishing vessels enter. Ooconta, equivalent to Archegonia in Fungi. OopPHoRIDIUM, organ in Lycopodiacez contain- ing large spores. OosPorRANGIA, spore-cases in some Algze. Oospor:E, a fertilised spore in Fungi. Opaque, dull, not shining. OPERCULUM, lid, applied to the separable part of the theca of Mosses; also applied to the lid of certain seed-vessels ; Oferculate, open- ing by a lid. ” OprosiTE, applied to leaves placed on opposite sides of a stem at the same level. OrBICULAR, rounded leaf with petiole attached to the centre of it. 821 OrcGaNoGEny, the development of organs, in- cluding their primitive condition and their gradual evolution. OrGaNnoGRapny, the description of the organs of plants. OrTHOPLOCE#, Cruciferee having conduplicate cotyledons. OrTHOS, straight ; in composition Ortho, same as Latin Rectus. é OrTHOSPERM«, seeds with the albumen flat on its inner face. ORTHOTROPAL and OrtTHoTrRopous, ovule with foramen opposite to the hilum ; embryo with radicle next the foramen, and hence in- verted. Osos, the force with which fluids pass through membranes in experiments on exos- mose and endosmose. Ovat, elliptical, blunt at each end. Ovary, the part of the pistil which contains the ovules. Ovarte, shaped like an egg, applied to a leaf with the broader end of the egg next the petiole or axis ; Ovate-lanceolate, alanceolate leaf, which is somewhat ovate. OvENCHYMA, tissue composed of oval cells. OvuLe, the young seed contained in the ovary. Paina, applied to the surface of the leaf, or any flat surface. PaLZonTo.ocy, the study of Fossils, PaLOPHYTOLOGY, the study of Fossil plants. PaLaTE, the projecting portion of the under lip of personate flowers. Patea or PALE, the part of the flower of Grasses within the glume; also applied to the small scaly laminz which occur in the receptacle of some Compositz. Paveaceous, chaffy, covered with small erect membranous scales. PaLMaTE and PaLMATIFID, applied to a leaf with radiating venation, divided into lobes to about the middle. PALMATIPARTITE, applied to a leaf with radi- ating venation, cut nearly to the base in a palmate manner. PanpburiForM, shaped like a fiddle, applied to an oblong leaf, with a sinus on each side about the middle. PANICLE, inflorescence of Grasses, consisting of spikelets on long peduncles coming off in a racemose manner. PANICULATE, forming a panicle. PANsPERMISM, development of cells from germs introduced from the atmosphere. PaPILIONACEOUS, corolla composed of vexillum, two alz, and carina, as in the Pea. PaPpittaTED and PapiLiosz, covered with small nipple-like prominences. Papprus, de hairs at the summit of the ovary or achene in Composite. They consist of the altered calyx. Pafgose, provided with pappus. 7 Para, eside or in place of; often used in com- position. Parapuyses, filaments, sometimes articulated, occurring in the fructification of Mosses and other Cryptogams; also applied by some authors to abortive petals or stamens. PaRASITE, attached to another plant, and deriv- ing nourishment from it. PARENCHYMA, Cellular tissue. 822 PaRIETAL, applied to placentas on the wall-of the ovary. PaRI-PINNATE, a compound pinnate leaf, end- ing in two leaflets. PARTHENOGENESIS, production of perfect seed with embryo, without the application of pollen. ParTITE or ParTep, cut down to near the base, the divisions being called Partitions. PaTetta, rounded sessile apothecium of Lichens. PATENT, spreading widely. PaTuo.ocy, Vegetable, same as Nosology. Patu Lous, spreading less than when patent. PEcTINATE, divided laterally into narrow seg- ments, like the teeth of a comb. PepATE and PEDATIFID, a palmate leaf of three lobes, the lateral lobes bearing other equally large lobes on the edges next the middle lobe. Pepice., the stalk supporting a single flower ; such a flower is Pedzcellate. PEDUNCLE, the general flower-stalk or floral axis. Sometimes it bears one flower, at other times it bears several sessile or pedi- cellate flowers. PELacic, growing in many distant parts of the ocean. PeELiicLe, the outer cuticular covering of plants. PELoria, a name given to a teratological phe- nomenon, which consists in a flower, which is usually irregular, becoming regular; for instance, when Linaria, in place of one spur, produces five. ” PELTATE, shield-like, fixed to the stalk by a point within the margin; Jeltaze hairs, at- tached by their middle. PENDULOUS, applied to ovules which are hung from the upper part of the ovary. PENIcILLATE, pencilled, applied to a_tufted stigma resembling a camel-hair pencil, as in the Nettle. PENNI-NERVED and PENNI-VEINED, the veins disposed like the parts of a feather, running from the midrib of the leaf to the margin. Penta, PenTe, five; same as Quingue in Latin. PENTAGONAL, with five angles having convex spaces between them. PrenTacynous, having five styles. PENTAMEROUS, composed of five parts; a pen- tamerous flower has its different whorls in five, or multiples of that number. PentTanprovs, having five stamens. PENTANGULAR, with five angles and five flat faces between them. Pero and Prpontpa, the fruit of the Melon, Cucumber, and other Cucurbitacez. Per, when placed before an adjective, some- times gives it the value of a superlative, as perpusillus, very weak; at other times it mieans through, as Zerfoliate, through the eaf, PERCURRENT, running through from top to bottom. PERENNIAL, living, or rather flowering, for several years. PERFOLIATE, a leaf with the lobes at the base, united on the side of the stem opposite the blade, so that the stalk appears to pass through the leaf. GLOSSARY. Pert, around ; in Latin, Circa. PERIANTH, a general name for the floral enve- lope ; applied in cases where there is only a calyx, or where the calyx and corolla are alike. PericarP, the covering of the fruit. PERICHATIAL, applied to the leaves surround- ing the fruit stalk or seta of Mosses. PericLapiuMm, the large sheathing petiole of Umbelliferae. PERICLINIUM and PERIPHORANTHIUM, the in- volucre of Composite. PERIDERM, a name applied to the outer layer of bark. Peripium, the envelope of the fructification in Gasteromycetous Fungi. PERIGONE, Same as Perianth. Some restrict the term to cases in which the flower is female or pistilliferous. It has also been applied to the involucre of Jungermanniez. PERIGYNIUM, applied to the covering of the pistil in the genus Carex. Pericynous, applied to corolla and stamens when attached to the calyx. PERIPHERICAL, applied to an embryo curved so as to surround the albumen, following the inner part of the covering of the seed. PeErisPErm, the albumen or nourishing matter stored up with the embryo in the seed. Perispore, the outer covering of a spore; the mother-cell of spores in Algze. PERISTOMATIC, cells surrounding a stoma, as in Ceratopteris. PERISTOME, the opening of the sporangium of Mosses after the removal of the calyptra and operculum. PeERITHECIUM, a hollow conceptacle in Lichens, containing spores, and having an opening at one end. PERSISTENT, not falling off, remaining attached to the axis until the part which bears it is matured. PrrsonaTE, a gamopetalous irregular corolla having the lower lip pushed upwards, so as to close the hiatus between the two lips. PertusE, having slits or holes. PERuL#, the scales of the leaf bud. PETALOID, like a petal. PETALS, the leaves forming the corolline whorl. PETIOLATE, having a stalk or petiole. Periotg, a leaf-stalk ; Petzolude, the stalk of a leaflet in a compound leaf. PuHALANGES, applied to stamens divided into lobes, like a partite or compound leaf. PHANEROGAMOUS, having conspicuous flowers. PHANEROS and PHeNos, conspicuous ; in com- position, Phanxero and Pheno. PHANOGAMOUS, same as Phanerogamous. PHLEBOIDAL, applied to moniliform vessels. aoc es a name applied in composition to the ark. PHORANTHIUM, applied to the receptacle of Composite. Puorus, PHorum, and Puorg, in words de- rived from the Greek, are used as termina- tions, meaning, that which bears ; equivalent to the Latin Herus and Fer. PHRAGMA, transverse division or false dissepi- ment in fruits. Prycocuromg, colouring matter in Lichens and in the lower Algz. Puyco.oey, the study of Alge or Seaweeds. GLOSSARY. Puvivarigs, the leaflets forming the involucre of Composite flowers. PuyLvopiuM, leaf-stalk enlarged so as to have the appearance of a leaf. Puy topy, change of an organ into true leaves. Puy tor, like a leaf. PuyYLLOLosBE®, cotyledons green and leafy. Puy .oprosis, the fall of the leaf. Puy iotaxis, the arrangement of the leaves on the axis. Puy ium, leaf, in composition PAyllo and Phyllous ; in Latin Folium. PuysioGNomy, general appearance, without reference to botanical characters. Puysiotocy, Vegetable, the study of the func- tions of plants. q PuyToGENEsis, the development of the plant. PuytoGrapny, the description of plants. Puyrovoey, the study of plants. PuytTon, a name given by Gaudichaud to the simple individual plant, as represented by a leaf. In words derived from the Greek, Phyton and Phyto mean plant. Puytozoa, moving filaments in the antheridia of Cryptogams. PILEORHIZA, a covering of the root, as in Lemna. Pixevs, the cap-like portion of the Mushroom, bearing the hymenium on its under side. Piose, provided with hairs; applied to pappus composed of simple hairs. SEs tissue composed ‘of tabular cells. Pin-zvep, applied to the flower of Primula, having long styles with stigma visible at the top of the floral tube. Pinna, the leaflet of a pinnate leaf. PINNATE, a compound leaf having leaflets ar- ranged on each side of a central rib. PINNATIFID, a simple leaf cut into lateral seg- ments to about the middle. PINNATIPARTITE, a simple leaf cut into lateral segments, the divisions extending nearly to the central rib. Pinnuces, the small pinnz of a bipinnate or ___ tripinnate leaf. Pistit, the female organ of the flower, composed of one or more carpels; each carpel being composed of ovary, style, and stigma. PisTILLATE, and PISTILLIFEROUS, applied to a female flower or a female plant. Pistivuipium, the female organ in Crypto- ams. PeACENTA, the cellular part of the carpel bear- ing the ovule. PiacenTary, a placenta bearing numerous ovules. PLACENTATION, the formation and arrange- ment of the placenta. Puatys, large or broad ; in composition Platy ; in Latin La¢us and Late. Piezi0n, several, in composition Plezo ; in Latin Pluri. PLEIOTRACHE#, spiral vessels with several fibres united. PiLenus, when applied to the flower, means double. PLEURENCHYMA, woody tissue. PLEuROCARP!, Mosses with the fructification proceeding laterally from the axils of the leaves. a PLEURORHIZE#, Cruciferous plants having the 823 radicle of the embryo applied to the edges of the cotyledons, which are called A ccumbent. Puicate and Pricative, plaited or folded like a fan, P.Lumosg, feathery, applied to hairs having two longitudinal rows of minute cellular pro- cesses. PLuMUut_E, the first bud of the embryo, usually enclosed by the cotyledons. Puurt in Latin words means several, PiuriLocutar, having many loculaments. PopeETium, a stalk bearing the fructification in some Lichens. , Popocarp, a stalk supporting the fruit. Popocynium, a stalk supporting an ovary. Poposrerm, the cord attaching the seed to the placenta. ' Pocon, beard; in Latin Barba. POLLARD-TREES, cut down so as to leave only the lower part of the trunk, which gives off numerous buds and branches. PoLten, the powdery matter contained in the anther. PoLLEN-TUBE, the tube emitted by the pollen- grain after it is applied to the stigma. Po.uinia, masses of pollen found in Orchids and Asclepiads. PoLyADELPHouS, stamens united by their fila- ments so as to form more than two bundles. PoLyanprous, stamens above twenty. Porycarpic, plants which flower and fruit many times in the course of their life. PoLycoTYLEDONOUS, an embryo having many cotyledons, as in Firs. PoLyEmBryONY, having more than one em- ryo. PotyGamous, plants bearing hermaphrodite as well as male and female flowers. ' PoLyGyneciAL, applied to multiple fruits formed by the united pistils of many flowers. Potycynous, having many pistils or styles. PoLyMORPHOUS, assuming many shapes. PoLyPETALOUS, a corolla composed of separate petals. PoLypuyLuous, a calyx or involucre composed of separate leaflets. Potys, many, in composition Poly; in Latin Multus. PoLysEPALous, a calyx composed of separate sepals. : PoLYSPERMAL, containing many seeds. Poms, a fruit like the Apple and Pear. Pores of the leaf, same as Stomata. Porous VESSELS, same as Pitted or Dotted vessels, Porrect, extended forwards. Posterior, applied to the part of the flower placed next the axis; same as Superéor. Posticus, same as Lxtrorse; applied to anthers. Poucu, the short pod or silicle of some Cru- ciferze. Pous, Popos, a foot or stalk, in composition Podo; in Latin Pes, Pedis. PR#FLORATION, same as “4 s¢ivation, PRAFOLIATION, same as Vernation. PremorsE, bitten, applied to a root or rhizome terminating abruptly, as if bitten off. PRICKLES, hardened epidermal appendages, of a nature similar to hairs. : Priming, the outer coat of the ovule. PrimorviL, the first true leaves given off by 824 the young plant ; also the first fruit produced on a raceme or spike. Primorpiac UTRric ce, the lining membrane of cells in their early state. Fs SUE NCHE SS tissue composed of prismatical cells. Process, any prominence or projecting part, or small lobe. ProcumsentT, lying on the ground. Pro-EmsBryo, cellular body in ovary, from which the embryo and its suspensor are formed. Sometimes Pro-embryo is used for Prothallus. Pro tFeRovs, bearing abnormal buds. Pro.iFIcaTION, axis prolonged beyond the flower, bearing leaves, and ending in an abortive flower-bud ; seen in Rose and Geum. Prong, prostrate, lying flat on the earth. PropaGuLuM, an offshoot, or germinating bud attached by a thickish stalk to the parent plant. ProsencuyMa, fusiform tissue forming wood. PROTANDROUS, or PROTERANDROUS, stamens reaching maturity before the pistil. PRoTHALLIUM, or PROTHALLUS, names given to the first part produced by the spore of an acrogen in germinating. ProtToGynous, or PROTEROGYNOUS, reaching maturity before the stamens. Protopiasm, the matter which seems to be concerned in the early formation of nuclei and cells. ‘ Prutnose, covered with a coarse granular secretion, as if dusted. PsEupo, false ; in Latin, Spurius. Psevpo-Bu Ls, the peculiar aerial stem of many epiphytic Orchids. PsreupDosPERMous, applied to single-seeded seed-vessels, suc. resembling seeds. PTeRIDOGRAPHIA, a treatise on Ferns. Prerocarpous, having winged fruit. Pusescence, short and soft hairs covering a surface, which is hence called Pubescent. PULVERULENT, covered with fine powdery matter. PutvinaTE, shaped like a cushion or pillow. Puxvinus, cellular swelling at the point where the leaf-stalk joins the axis. PuncrarTep, applied to the peculiar dotted woody fibres of Conifera. Putamen, the hard endocarp of some fruits. Pycnipe, a papilleform or wart-like minute cellular reproductive body in the thallus of Lichens. PyrENa#, stony coverings of the seeds in the edlar. Pyripium, same as Pome. Pyriror, pear-shaped. nae and Pyxipium, a capsule opening by a 1d. pistil lants bearing as Achenes, eee in composition, means four times. UADRIFARIOUS, in four rows. QuanriFID, four-cleft, cut down into four parts to about the middle. QuanpRIJUGATE, having four pairs of leaflets. So having four loculaments. UADRIPARTITE, divided deeply into four parts. QuartinE, the fourth coat of the ovule, which often is changed into albumen. GLOSSARY. QuaTERNATE, leaves coming off in fours from one point. Quinary, composed of five parts, or of a mul- tiple of five. QuinaTE, five leaves coming off from one point. * Quincunx, when the leaves in the bud are five, of which two are exterior, two interior, and the fifth covers the interior with one margin, and has its other margin covered by the ex- terior. Quincuncial, arranged ina quincunx. Qur1NnQUE, in compound words means five. QurnquEFin, five-cleft, cut into five parts as far as the middle. 7 QuinquELocuLak, having five loculaments. QuINQUEPARTITE, divided deeply into five parts. QuinTINE, the fifth coat of the ovule, other- wise called the embryo-sac. Race, a permanent variety. Racrmg, cluster, inflorescence in which there is a primary axis bearing stalked flowers. RacemosE, flowering in racemes. Racuis, the axis of inflorescence ; also applied to the stalk of the frond in Ferns, and to the common stalk bearing. the alternate spikelets in some Grasses. RapianT, applied to flowers which form a ray- like appearance, as seen in Umbellifere and in Viburnum, etc. RapiaTE, disposed like the spokes of a wheel ; also applied to the florets of the ray or cir- cumference of the capitula of Composite. Rapicaz, belonging to the root, applied to leaves close to the ground, clustered at the base of a flower stalk. Rapic te, the young root of the embryo. Raptus, the ray or outer part of the heads of Composite flowers. Ramat, belonging to the branches. RameEnTa, the scales or chaff of Ferns. RamosE and Ramous, branched. Rapue, the line which connects the hilum and the chalaza in anatropal ovules. RapuipEs, crystals found in cells, which are hence called Raphidian. RECEPTACLE, the flattened end of the peduncle or rachis, bearing numerous flowers in a head ; applied also generally to the extremity of the peduncle-or pedicel. RECLINATE, curved downwards from the hori- zontal, bent back up. RECTEMBRYE4, the embryo straight in the axis of the seed. REcTINERVIS and RECTIVENIUS, straight and parallel veined. RECTISERIAL, leaves disposed in a rectilinear series. RECURVED, bent backwards. REvDUPLICATE, edges of the sepals or petals turned outwards in zstivation. Reema, seed-vessel composed of elastic cocci, as in Euphorbia. REGULAR, applied to an organ the parts of which are of similar form and size. RELIQUI#, remains of withered leaves attached to the plant. RENIFORM, in shape like a kidney. - REPANDy having a slightly undulated or sinuous margin, GLOSSARY. RepLum, a longitudinal division in a pod, formed by the placenta, as in Cruciferee. HE OFINARE, inverted by a twisting of the stalk. RETICULATED, netted, applied to leaves having a network of anastomosing veins. RetiFors, like network. Rerinacutum, the glandular viscid portion at the extremity of the caudicle in some pollinia. Retinervis and Retiventus, having reticu- lated veins. RETRoRSE, turned backwards. Retuse, when the extremity is broad, blunt, and slightly depressed. REVOLUTE and ReEvo.utive, leaf with its edges rolled backwards in vernation. Ruiz, in words derived from the Greek, means root. RHIZANTH, same as Rhizogen. Rurzocarp, applied to Marsilea, as producing spore-cases on root-like processes. RHIZOGEN, a name applied to such plants as Baesia, which consist of a flower and root only. RuizoME, a stem creeping horizontally, more or less covered by the soil, giving off buds above and roots below. RuizoTaxis, the arrangement of the roots. RuHomBoID, quadrangular form, not square, with equal sides. Rictus, the throat or chink in personate flow- ers, RINGENT, a labiate flower, in which the upper lip is much arched. Root-stock, same as Rhizome. Rosaceous, applied to corollas having separate sessile petals like the Rose. RosETTE, leaves disposed in close circles form- ing a cluster. RosTEL_uM, a peculiar body in Orchids, often cup-shaped, bearing the glands of the pollen- mass, with its viscid balls attached. RostraTE, beaked, having a long sharp point. Rotate, a regular gamopetalous corolla with a short tube, the limb spreading out more or less at right angles. RotarTion or GyRATION, a peculiar circulation of the cell sap, seen in Hydrocharidacez, Characez, etc. : RuDIMENTARY, an organ in an abortive state, arrested in its development. Rucosg, wrinkled. RuMINATE, applied to mottled albumen. RUuNCINATE, a pinnatifid leaf with a triangular termination and sharp divisions pointing downwards, as in Dandelion. Ruwnenr, a prostrate shoot rooting at the end; a stoton. BAcCA Te forming a sack or bag, seen in some etals. SAcrrtaTE, like an arrow, a leaf having two prolonged sharp-pointed lobes projecting downwards beyond the insertion of the petiole. SALVER-SHAPED. See Hyfocratertiform. Samara, a winged dry fruit, as in the Elm. Sarcocarp and SARCODERM, the mesocarp of the fruit, having become succulent. SARCOLOBE#, cotyledons thick and fleshy, as in Bean and Pea. SARMENTUM, sometimes meaning the same as 825 Flagellum, or runner, at other times applied to a climbing stem which supports itself by means of others, as in Vine. Scaprous, rough, covered with very stiff short hairs; Scabrizscudus, somewhat rough. SCALARIFORM, vessels having bars like a ladder, seen in Ferns. ScanDEnT, climbing by means of supports, as on a wall or rock, Scars, a naked flower-stalk, bearing one or more flowers arising from a short axis, and usually with radical leaves at its base. Scarious, having the consistence of a dry scale, membranous, dry, and shrivelled. Scuizocarp, dry seed-vessel splitting into two or more 1-seeded mericarps. Scion, the young twig used as a graft. SEUEEOSEN, the thickening matter of woody cells, ScosiForM, in the form of filings, or like fine sawdust. Scosina, the flexuose rachis of some Grasses. Scorpio1DaL, like the tail of a scorpion, a pe- culiar twisted cymose inflorescence, as in Boraginacez. Scorpior1p CymMg, flowers arranged alternately or ina double row along one side of a false axis, the bracts forming a double row omthe other side ; bracts often wanting. 2 ScroBICULATE, pitted, having small {depres- sions. ScuTELLaTE, like a shield. ScuTELLUuM, a sort of apothecium in Lichens. SEcUND, turned to one side. Secunping, the second coat of the ovule within the primine. SEGREGATE, separated from each other. SELF-FERTILISATION, pistil fertilised by the pollen of the stamens in the same flower. Sem, half, same as the Greek Hemi. SEMIFLOsCULOUS, same as Ligulate. SEMINAL, applied to the cotyledons, or seed- leaves. SEPAL, one of the leaflets forming the calyx. SEPTATE, divided by septa or partitions. SEPTEM, seven, in Greek Hedia. SEPTENATE, organs approaching in sevens; a compound leaf with seven leaflets coming off from one point. SEPTICIDAL, dehiscence of a _ seed-vessel through the septa or edges of the carpels. SEPTIFRAGAL, dehiscence of a ‘seed-vessel through the back of the loculaments, the valves also separating from the septa. SEPTULATE, having spurious transverse dissepi- ments. . SEPTUM, a division in an ovary formed by the sides of the carpels. Sericzous, silky, covered with fine, close- pressed hairs, SERRATE or SERRATED, having sharp processes arranged like the teeth ofa saw. Suzserrate, when these are alternately large and small, or where the teeth are themselves serrated. SERRATURES, pointed marginal divisions ar- ranged like the teeth of a saw. SERRULATE, with very fine serratures. SEsqul, in composition, means one and a half. SEsSILE, without a stalk, as a leaf without a petiole. - SETA, a bristle or sharp hair ; also applied to the gland-tipped hairs of Rosacez and 826 Hieracia; and to the stalk bearing the theca in Mosses. ’ Sreracrtous and SeETIFORM, in the form of bristles. SETIGEROUS, bearing seta. SETOSE, covered with setz. Sex, in Latin, six; same as Greek Hera. SHeaTu. See Vagina. Sivicuca or SILIcE, a short pod with a double placenta and replum, as in some Cruciferz. SILIcuLos&, bearing a silicula. Si1ziqua, a long pod similar in structure to the silicula. S1LiqU£FoRM, fruit like a siliqua in form. Siriquos@, bearing a siliqua. SIMPLE, not branching, not divided into sepa- rate parts; Simple fruits are those formed by one flower. SinisTRORSE, directed towards the left. SINuATED, the margin having numerous large obtuse indentations. Sinvous, with a wavy or flexuous margin. SLASHED, divided by deep and very acute in- cisions. Sopoes, a creeping underground stem. Sociat Pants, such as grow naturally in groups or masses. Sorepia, powdery cells on the surface of the thallus of some Lichens. Sorosis, acompound or polygyncecial succulent fruit, such as Breadfruit and Mulberry ; also applied by some to the fructification in Alaria, containing pyriform stipitate spores. Sorus, a cluster of sporangia in Ferns ; applied also to fructification in Alaria, containing pyriform stipitate spores. Spapix, a succulent spike bearing male and female flowers, as in Arum. SpaTHACEOUS, having the aspect and membran- ous consistence of a spathe. SpaTHE, large membranous bract covering numerous flowers. ; SPATHELL4, another name for the glumellz of Grasses. SpaTHULATE, shaped like a spathula, applied to a leaf having a linear form, enlarging sud- denly into a rounded extremity. Spawn, same as Mycelium. Speciric CHARACTER, the essential character of a species. SPERMATIA, motionless spermatozoids in the spermogones of Lichens and Fungi. SPERMATOzOIDS, moving filaments contained in the antheridia of Cryptogams ; called also phytozoa and antherozoids. SPERMODERM, the general covering of the seed. Sometimes applied to the episperm or outer covering. SPERMOGONE, a microscopic conceptacle in Lichens, containing reproductive bodies called Spermatia; also a conceptacle con- taining fructification in Fungi. ; PH/ERAPHIDES, globular clusters of raphides, as in Ficus. SPH SRENCHY MA, tissue composed of spherical cells, SpikE, inflorescence consisting of numerous flowers sessile on an elongated axis. SPIKELET, small cluster of flowers in Grasses. Spine or THoRN, an abortive branch with a hard sharp point. : SPINESCENT or SpINosE, bearing spines. GLOSSARY. Sprrav VESSELS or SprrorpEA, having a spiral fibre coiled up inside a tube. SPIRILLUM, same as Sfermatozoid. SprroLoBE#, Cruciferze having the cotyledons folded transversely, the radicle being dorsal. SPONGIOLE or SPONGELET, the cellular extre- mity of a young root. Sporapic Piants, confined to limited local- ities. SPORANGIUM, a Case containing spores. Spore, a cellular germinating body in Crypto- gamic plants. Sroripium, a cellular germinating body in Cryptogamics containing two or more cells in its interior. SporocarP, the involucre or ovoid-sac con- taining the organs of reproduction in Mar- sileacez. SporopHorg, a stalk supporting a spore. Sporopuores, filamentous, processes support- ing spores in Fungi. Sporozorp, a moving spore furnished with cilia or vibratile processes. Spur, same as Calcar. Squama, a scale ; also applied to bracts on the receptacle of Composita, to bracts in the in- florescence of Amentiferz, and to the lodicule of Grasses. SQUAMOSE, covered with scales. SQUARROSE, covered with processes spreading at right angles or in a greater degree. Sracuys and StTacuya, in Greek words signify a spike. STameEn, the male organ of the flower, formed by a stalk or filament and the anther con- taining pollen. STAMINATE and STAMINIFEROUS, applied to a male flower, or to plants bearing male flowers. STAMINODIUM, an abortive stamen. - STAMINoDY, change of an organ into stamens. STANDARD, same as Vextllum. STELLATE or STELLIFORM, arranged like a star. SrericMaTA, cells bearing naked spores ; also cellular filaments bearing spermatia and stylo- spores, in the Spermogones and Pycnides of Lichens. STERILE, male flowers not bearing fruit. Sticuip1a, pod-like receptacles containing spores. Sticuous at the termination of words means a row, as adistichous, in two rows. Sticma, the upper cellular secreting portion of the pistil, uncovered with epidermis ; Stig- matic, belonging to the stigma. . StImuLus, a sting, applied to stinging hairs with an irritating secretion at the base. Stipe, the stem of Palms and of Tree-ferns ; also applied to the stalk of Fern-fronds, and to the stalk bearing the pileus in Agarics. STIPEL, a small leaflet at the base, of the pinnz or pinnules of compound leaves. STIPITATE, supported on a stalk. 7 SripuLary, applied to organs occupying the place of stipules, such as tendrils. STIPULATE, furnished with stipules. STieu.e, leaflet at the base of other leaves, having a lateral position, and more or less changed either in form or texture. Stoton, a sucker, at first aerial, and then turn- ing downwards and rooting. GLOSSARY. StotoniFeRous, having creeping runners which root at the joints. Stoot, a plant from which layers are pro- pagated, by bending down the branches so as to root in the soil. Stomares and Sromata, openings in the epidermis of plants, especially in the leaves. STRANGULATED, contracted and expanded ir- regularly. STRAP-SHAPED, same as Ligudate; linear, or about six times as long as broad. SrRrA, a narrow line or mark. STRIATED, marked by streaks or striae. Srricose, covered with rough, strong, ad- pressed hairs. . Stripes, a name given to the Vitte of Umbel- liferze, STROBILUS, a cone, applied to the fruit of Firs as well as to that of the Hop. STROPHIOLE, a sort of aril or swelling on the surface of a seed. Struma, a cellular swelling at the point where a leaflet joins the midrib; also a swelling below the sporangium of Mosses. Stuprose, having a tuft of hairs. STYLE, the stalk interposed between the ovary and the stigma. Sryopop, an epigynous disk seen at the base of the styles of Umbelliferze. 3» STYLosporeE, a spore-like body borne on a sterigma or cellular stalk, in the Pycnides of Lichens. Sus, in composition, means a near approach to, as sub-rotund means nearly round. Suserous, having a corky texture. Susicutum, same as Hypothallus. SUBTERRANEAN, underground, same as Hy- pogeal. SuBULATE, shaped like a cobbler’s awl. Succisus, abrupt, as it were cut off, same as Premorse. SurrruTicose, having the characters of an undershrub. Sutcare, furrowed or grooved. Superior, applied to the ovary when free from the calyx ; to the calyx when it is attached to the ovary ; to the part of a flower placed next the axis. SuPERVOLUTE or SUPERVOLUTIVE, a leaf rolled upon itself in vernation. Surcutus, a sucker, a shoot thrown off under- ground, and only rooting at its base. SUSPENDED, applied to an ovule which hangs from a point a little below the apex of the ovary. chee en the cord which suspends the em- bryo, and is attached to the radicle in the young state. SuTURAL, applied to that kind of dehiscence which takes place at the sutures of the fruit. Sutures, the part where separate organs unite, or where the edges of a folded organ adhere ; the ventral suture of the ovary is that next the centre of the flower; the dorsal suture corresponds to the midrib. ‘Syconus, a multiple or polygyncecial succulent hollow fruit, as in the Fig. Sympois. Seep. 412. Symmetry, applied to the flower, has refer- ence to the parts being of the same number, or multiples of each other. _ Syn, in composition, means united. 827 Synacme, stamens and pistils reaching ma- turity at the same time. SYNANTHEROUS, anthers united. SyYNANTHOS, flowers united together. Syncarrous, carpels united so as to form one ovary or pistil. SYNGENESIOUS, same as Synantherous. SynocHREATE, stipules uniting together on the opposite side of the axis from the leaf. Synsporous, applied to Algee which propagate by conjugation of cells. TAPHRENCHYMA, pitted vessels, same as Both- renchyma. TAp-RooT, root descending deeply in a tapering undivided manner. Taxonomy, principles of the classification of plants. : TEGMEN, the second covering of the seed, called also Exdopleura. TEGMENTA, scales protecting buds. - TENDRIL. See Cirrus. TERATOLOGY, study of monstrosities and pecu- liar morphological changes. TERCINE, the third coat of the ovule, forming the covering of the central nucleus. TERETE, nearly cylindrical, somewhat tapering into a very elongated cone, the transverse section nearly circular. TERNARY, parts arranged in threes, TERNATE, compound leaves composed of three leaflets. TesTA, the outer covering of the seed; some apply it to the coverings taken collectively. TESTICULATE, root having two oblong tuber- cules. TetTRA, in Greek words four; in Latin Quater or Quadri. TETRADYNAMOUS, four long stamens and two short, as in Cruciferae. TETRAGONOUS, or TETRAGONAL, having four angles, the faces being convex. TeTRAGYNouS, having four carpels or four styles. TETRAMEROUS, composed of four parts; a flower is tetramerous when its envelopes are in fours, or multiples of that number. TETRANDROUS, having four stamens. TETRAPTEROUS, having four wings. ‘TETRAQUETROUS, having four angles, the faces being concave. TETRASPORE, a germinating body in Alge composed of four spore-like cells; but also applied to those of three cells. TETRATHECAL, having four loculaments. THALAMIFLORAL, parts of the floral envelope inserted separately into the receptacle of thalamus. THALAMUS, the receptacle of the flower, or the part of the peduncle into which the floral organs are inserted. THALLOGENS or THALLOPHYTES, plants pro- ducing a thallus. THALLUS, cellular expansion in Lichens and other Cryptogams, bearing the fructification. THECA, sporangium or spore-case containing spores. THECAPHORE, a stalk supporting the ovary. TuEcasporous, applied to Fungi which have the spores in thecz. Tuorn, an abortive branch with a sharp point. Turoat, the orifice of a gamopetalous flower. 828 THRUM-EYED or THUMB-EYED, flowers having short styles, where the stigma does not appear at the upper part of the tube of the corolla, as in Primula. Tuyrsvs, a sort of panicle, in form like a bunch of grapes, the inflorescence being definite. TIGELLus, the young embryonic axis. To1sE is equal to 1.94904 metres or 6.39459 English feet.’ ToMENTOSE, covered with cottony, entangled pubescence, called somentum. Torutoss, presenting successive rounded swell- ings, as in the moniliform pods of some Crucifere. Torus, another name for thalamus ; sometimes applied to a much-developed thalamus, as in Nelumbium. TRACHEA, a name for spiral vessels. TRACHENCHYMA, tissue composed of spiral vessels, TRANSPIRATION, the exhalation of fluids by leaves, etc. Treis, three ; Tris, thrice, in composition 777. TRIADELPHOUS, stamens united in three bundles by their filaments. Trianprous, having three stamens, ‘TRIANGULAR, having three angles, the faces being flat. . TRICHOPHORE, cellular body supporting the Cystocarp in some Floridez. TRIcHOGYNiuM, a hair-like process in Floridez, surmounting a cell, which after fertilisation becomes a cystocarp. TRICHOTOMOUS, divided successively into three branches. Tricoccous, formed, by three elastic monosper- mal carpels. ‘TRICOSTATE, three-ribbed, ribs from the base. TricuspipaTe, having three long points or cuspides. 5 TRIDENTATE, having three teeth. TriFaRious, in three rows, looking in three directions. Tririp, three-cleft, a leaf divided into three segments which reach to the middle. TRIFOLIATE or TRIFOLIOLATE, same as Ter- nate. When the three leaves come off ‘at one point the leaf is ternately-trifoliolate ; when there is a terminal stalked leaflet and two lateral ones it is pznnately-trifoliolate. Triconous, having three angles, the faces being convex. Tricynous, having three carpels or three styles. TRIJUGATE, having three pairs of leaflets. TRILOcULAR, having three loculaments. TRIMEROUS, composed of three parts ; a trémer- ous flower has its envelopes in three or multiples of three. Trimorpuic, three forms of flowers in one species, each on a different plant, and having stamens and pistil ; there are three lengths of stamens, of which two lengths are in each flower ; and there are three lengths of styles differing in each form of flower, not associ- ated with stamens of corresponding length. TrIneERvis, having three ribs springing to- gether from the base. Triacrous, or TR101Cous, a species producing . hermaphrodite, staminate, and_pistillate flowers on three separate individuals. Triaiciousty-HERMAPHRODITE, same as Tri- morphic. GLOSSARY. — TriparTITE, deeply divided into three. TRIPINNATE, a compound leaf three times divided in a pinnate manner. TRIPINNATIFID, a pinnatifid leaf with the seg- ments twice divided;in a pinnatifid manner. TRIPLICOSTATE, three ribs proceeding from above the base of the leaf. Triquetrous, having three angles, the faces being concave. TRISTICHOUs, in three rows. TRITERNATE, three times divided in a ternate manner. TROPHOSPERM, a name for the placenta, TRUNCATE, terminating abruptly, as if cut off at the end. Tryma, drupaceous fruit like the Walnut; a superior x-celled 1-seeded fruit, with a coriaceous or fleshy epi- and mesocarp; a stony 2-valved endocarp with partitions on inner concave surface, as in Walnut. Tuper, a thickened underground stem or branch, as the potato. TuBERCULE, the swollen root of some terrestrial Orchids. TusBeErovs, applied to roots in the form of tuber- cules, Tusuvar, applied to the regular florets of the Compositz. TUBULAR-BELL-SHAPED, applied to a campanu- late corolla, which is somewhat tubular in its ‘orm. TuNIcATED, applied to a bulb covered by thin external scales, as the Onion. TurRBINATE, in the form of a top. Turio, a young shoot covered with scales sent up from an underground stem, as in Aspara- Ss. TyLosis, development of irregular cells in the interior of pitted vessels, seen in many exogenous trees, as Walnut, Oak, and Elm. Type, the perfect representation or idea of any- = 2 ‘ . 7 Tyricat, applied to a specimen which has emi- nently the characteristics of the species, or to a species or genus characteristic of an order. Une, inflorescence in which numerous stalked flowers arise from one point. UMBELLULE, a small umbel, seen in the com- pound umbellate flowers of many Umbelli- ere. UmpiicaTE, fixed to a stalk by a point in the centre. Umpi.icus, the hilum or base of a seed. Umpo, a conical protuberance on a surface. | UmBonaTE, round, with a projecting point in the centre, like the boss of an ancient shield. UmBRACULIFEROUS, in the form of an expanded umbrella. UncinaTE, provided with an wxcus or hooked process. UNDvECcIM, eleven; in Greek, Exdeca. Uncuts, claw, the narrowed part of a petal; such a petal is called Unguzculate. UnI, in composition, one, same as Greek Mono. UNICELLULAR, composed of a single cell, as some Alge. UNILATERAL, arranged on one side, or turned to one side. , Uniocu.ar, having a single Zocudus or cavity. UniParous, a cymose inflorescence in which the primary axis produces one bract, and GLOSSARY. from the axil of this a second axis arises, and so on in succession; a false axis is thus formed. Uniparous, scorpioidal cyme. See Scorpioid. UNISEXUAL, of a single sex, applied to plants having separate male and female flowers. URCEOLATE, urn-shaped, applied to a gamo- petalous globular corolla, with a narrow opening. UstuLateE, blackened. UTRICLE, a name for a thin-walled cell, or for a bladder-like covering. UrricuLus, applied to a kind of fruit like the achene, but with an inflated covering ; also to the persistent confluent perigone of Carex; in Alga applied to a loose cellular envelope containing spores. Vacina, sheath, lower sheathing some leaves. VALLECULA, an interval the fruit of Umbellifere. VALVATE, opening by valves, like the parts of certain seed-vessels, which separate at the edges of the carpels. VaLvaTE EsTIVATION, when leaves in the flower-bud are applied to each other by their margins only. VALVATE VERNATION, when leaves in the Jeaf-bud are applied to each other by their margins only. Va.ves, the portions which separate in some dehiscent capsules. A name also given to the parts of the flower of grasses. ° VASCULAR TISSUE, composed of spiral vessels and their modifications. VASIFORM TISSUE, same as Dotted vessels. Veins, bundles of vessels in leaves. VELuM, veil, the cellular covering of the gills of an Agaric in its early state. VELUTINOUS, having a velvety appearance. VENATION, the arrangement of the veins. VENTRAL, applied to the part of the carpel which is next the axis. . VeENTRICOSE, swelling unequally on one side. VERMICULAR, shaped like a worm, or having worm-like movements. . VeERNATION, the arrangement of the leaves in the bud. : VERRUCOSE, covered with wart-like excre- scences. Seaeg VERSATILE, applied to an anther which is at- portion of etween the ribs on 829 tached by one point of its back to the fila- ment, and hence is very easily turned about. VERTICIL, a whorl, parts arranged opposite to each other at the same level, or, in other words, in a circle round an axis. The parts are said to be Vertictllate. VERTICILLASTER, a false whorl, formed of two nearly sessile cymes placed in the axils of opposite leaves, as in Dead-nettle. VESICLE, another name for a cell or utricle. VESSELS, tubes with closed extremities. VEXILLARY, applied to zestivation when the vex- illum is folded over the other parts of the flower. VEXILLUM, standard, the upper or posterior petal of a papilionaceous flower. VIGINTI, twenty, same as Greek Jcosz. ViLLous, covered with long soft hairs, and having a woolly appearance. VirGaTE, long and straight like a wand. Viscous, clammy, like bird-lime. VITELLUS, the embryo-sac when persistent in the seed. . Vit, cells or clavate tubes containing oil in the pericarp of Umbelliferze. Viviparous, plants producing leaf-buds in place of fruit. VouuBILE, twining, a stem or tendril twining round other plants. VoLva, wrapper, the organ which encloses the parts of fructification in some Fungi in their young state. WHORLED, same as Verticillate. Wines, the two lateral petals of a papilionaceous flower, or the broad flat edge of any organ. XANTHOPHYLL, yellow colouring matter in plants. XanrTuos, yellow, in composition Yantho. XEROPHILOUS, plants requiring a hot and dry climate. XYLEM, woody tissue. Xybocarpous, fruit which becomes hard and woody. ZoopPuiLous, applied to plants which are fer- tilised by the agency of insects. ZoosPoORE, a moving spore provided with cilia ; called also Zoosferm and Sforozoid. ° ZyYGOSPORE, compound spore formed by con- jugating cells in Fungi. ZOOTHECA, a cell containing a spermatozoid. 830 ABBREVIATIONS AND SYMBOLS. ABBREVIATIONS AND SYMBOLS.* ‘THE names of Authors are abridged in Botanical works by giving the first letter or syllable, etc.—Thus, L. stands for Linneus ; DC. for De Candolle ; Br. for Brown; Lam. and Lmk. for Lamarck ; Hook. for Hooker ; Hook. fil. for Hooker junior ; Lindl. for Lindley ; Arn. for Arnott ; H. and B. for Humboldt and Bonpland ; H. B. and K. for Humboldt, Bonpland, and Kunth; W. and A. for Wight and Arnott ; Benth. for Bentham ; Berk. for Berkeley ; Bab. for Babington, etc. The Symbol oo or 00 means an indefinite number ; in the case of stamens it means above 20. © means Monocarpic, flowering and fruiting once during life; duration uncertain, O © or A. means a Monocarpic annual plant ; flowering and fruiting within the year and then dying. 3 ©© © © or B. means a biennial plant ; flowering and fruiting in the second year. ; 2zf A or P. means a perennial plant ; Rhizocarpic. 5 means a woody plant. 5 means an undershrub. h 5 or Sh. means a shrub; 5 means a Tree under 25 feet; T. or 5 a Tree above 25 feet. ~ means a climber; ) turning to the left ; ( turning to the right. O = Cotyledons accumbent, radicle lateral ; Pleurorhizese. O || Cotyledons incumbent, radicle dorsal ; Notorhizez. O> Cotyledons conduplicate, radicle dorsal ; Orthoploces. O || || Cotyledons plicate or folded, radicle dorsal ; Spirolobee. O || Il || Cotyledons biplicate or twice folded, radicle dorsal ; Diplecolobez. % Hermaphrodite flower, having both stamens and pistil. $ Male, staminiferous, staminate, or sterile flower. Q Female, pistilliferous, pistillate, or fertile flower. 6 2 Unisexual species, having separate male and female flowers. &-¥ Moneecious species, having male and female flowers on the same plant. & :2 Dicecious species, having male and female flowers on different plants. 8 & P Polygamous species, having hermaphrodite and unisexual flowers on the same or different plants. ! Indicates certainty as to a genus or species described by the author quoted. ? Indicates doubt as to the genus or species. O Indicates absence of a part. vv. sp. or v. v. Vidi vivam spontaneam, indicates that the author has seen a living native specimen of the plant described by him. v. v.¢, Vidivivam cultam, indicates that he has seen a living cultivated specimen. v. $. sp. or v. s. Vidi siccam spontaneam, indicates that he has seen a dried native specimen. v, ». «. Vidi siccam cultam, indicates that he has seen a dried cultivated specimen, v. in h. Vidi in Herbario ; seen in Herbarium. * For further remarks on Abbreviations and Symbols, see page 412. ABAXILE or abaxial, 342 Abbattichim, 495 Abbreviations and symbols, 412, 830 Abele, 592 Aberia, 440 Abies, 599 Abietineze, 597 region of, 676 Abietites, 750 Abiogenesis, 15 Abnormal roots, 39 Abolboda, 619 Abruptly pinnate, 93 Abrus, 479 Absinthium, 52r Absorption of fluids, 121, 124, 142 Acacia, 96, 482 Acalypha, 580 Acanthacee, 556 Acanthodium, 556 Acanthus, 556 Acaules, 44 Acclimatising, 716 Accrescent, 200 Accumbent, 112, 340 Aceracez, 458 Achenium, 309 Achimenes, 541 Achlamydez, 560 Achlamydeous or naked flowers, 192, 367 Achlya, 272, 655 Achras, 53% Achromatic, 763 Achu, 628 Acicular, 88 Acids, Organic, 170 Acinaciform, go Aconite, fruit of, 312 Aconitum, 427 Acorez, 625 Acorn, 315 Acorus, 625 Acotyledonous, 334 Acotyledonous germi- nation, 357 embryo, 265, 335, 362 Acotyledons, 635 —- leaves of, ror —— phyllotaxis of, 107 INDEX. es Acotyledons, root of, 43 —— spore of, 334 —— symmetry in, 365 Acrobrya, 70, 635. Acrocarpi, 643 Acrocomia, 622 Acrogenous or Acoty- ledonous stem, 70 Acrogens, 635 —— course of sap in, 14 Actza, 427 Actinenchyma, 4 Aculei, 32 Acuminate, 89 Adam’s Needle, 615 Adansonia, 449 Adanson’s floral re- gion, 685 Adder’s Tongue, 639 Adherent, 98, 224, 246 Adhesion, 98, 173, 365, 369 Adiantum, 639 Adnate, 98, 224 Adoxa, 51x Adventitious, 116 Adventitious root, 39, 336, fEcidium, 649 figle, 455 Aerial leaf-buds, 114 Aerial root, 38 “Esculus, 459 4Estivation, 193 Aktheogame, 635 éthiopian Lily, 625 —— Pepper, 430 “Ethophyllum, 747 Ethusa, ce Affinity, 674 Africa Nodthern, flora of, 685 — South, flora of, 689 2 —— Tropical, flora of, 685 Agallochum, 572 Agamous, 212 Agar-agar, 655 Agarics, phosphore- scent, 389 Agaricus, 649 Agathophyllum, 569 Agathotes, 540 Agave, 611 Agavez, 611 Age of trees, 360 Agelza, 476 Aggregate fruits, 310 Agrarian region in Bri- tain, 713 Aabin and Ahaloth, eels 13 Air in germination, 345 Air-plants, 127, 141, 613 Aizoon, 500 Ajowan, 508. Alabastrus, 193 le or wings, 205 Alangiacez, 510 Alaria, 655 Albumen, 327, 331 Albumin, vegetable, 166 Albuminous, 332 Alburnum, 55 Alder, 593 Aldrovanda, 441 Alethopteris, 745 Aleurites, 582 Alfonsia, 626 Alga, 652 Algz of the chalk, 75z Alge, reproduction of, 269 Algaroba Bean, 481 Algum - trees, 480, 574, Alhagi, 479 Alhenna, 487 Alismaceze, 623 Alkaloids, 170 Allamanda, 537 Alliez, 614 Alligator pear, 569 Allium, 615 Allon, 595 Allspice, 487, 492 mond, 312, 485 Almug-tree, 480, 574 Alnus, 593 Aloes, 615 Aloes-wood, 572 Aloineze, 614 Aloysia, 555 Alpine- Arctic flora, 679 Alpine plants of Bri- tain, their limits, 7x2 —— vegetation of Great Britain, 707 —— travelling, prepa- ration for, 804 —— vegetation, zones of, 698 Alpinia, 606 Alps, Maritime, range of trees on, 697 Alsinaceous corolla, . 205 Alsinez, 445 | Alsodez, 440 Alsodeia, 441 Alstonia, 537 Alstrémeria, 61 Alternate, 103 Alternately-pinnate, 93 Alternation of parts of flowers, 192 | Altingiacez, 504 Altitudinal range of vegetation, 698 Alumina in soils, 135 Amadou, 650 Amanita, 649 ‘Amarantaces: fruit of, 310 Amaranthacez, 562 Amaranthus, 562 Amaryllidaceze, 611 Amber, 754 Atop Pitch-tree, Arebeina: 563 Amenta, 190 Amentifera, fossil, 758 Amentum, 178 American ’Aloe, 611 Amherstia, 478 Ammi, 508 Ammonia, source of nitrogen, 127 Ammoniac, 507 oe manures, Amsophila, 632 Amnios, 253, 326 Amomum, 605 Ampelidez, 460 Ampelopsis, 462 Amphigame, 644 Amphitropal, 256, 342 832 Ampulla, 38, 100 Amygdalez, 483 Amygdalin, 167 Amygdalus, 485 Amyridacez, region of, 685 Amyridez, 475 Anabasis, 563 Anacardiacez, 473 Anacharis, 602 —— rotation in cells of, 153 Anacyclus, 520 Anagallis, 315, 558 —— fruit of, dehis- cence of, 307 Analogy, 674 Anamirta, 430 Ananassa, 613 Anastatica, 437 Anastomosis of vessels, 2r Anatropal, or Anatro- pous, 256, 330 Anchusa, 546 Anda, 583 Andes flora, 686, 696 Andira, 480 -Andrea, 643 Andreecium, 212 Andrographis, 556 Andromeda, 527 Androphore, 219 Andropogon, 631 Androsace, 55: Androspores, 270 Anemia, 639 Anemonez, 426 Anemophilous, 284 Anethum, 508 Anfractuose, 223 Angelica, 507 Angienchyma, 16 Angiopteris, 639 Angiospermous, 326 Angiospermous_ dico- tyledons of the chalk, 751 Angiospermous flower- ing plants, fertilisa- tion in, 294 Angiosperms, fossil, reign of, 750 Atigiosporze, 635 Angostura, 469, — false, 538 Angustisepte, 436 Anigosanthus, 610 Anise, 508 Anisostemonous, 215 Annual plants, 359 ~ Annular rings, 251, 361 — vessels, 19 Annularia, 738 Annulate ferns, 639 Annulated root, 40 Anomopteris, 747 Anonacee, 429 Antarctic region, 688 Anterior, applied to the parts of a flower, 195 INDEX. Anthemis, 520 Anther, 216, 220 —— abnormalities, 226 —— appendages, 224 —— colour of, 226 —— coverings of, 220 —— dehiscence of, 225 —— lobes, form of, 222 Anthericez, 614 Anthericum, 614 Antheridia, 234, 263, 267, 278 Antherozoids, 234, 265 Anthemis, 520 Anthesis, 193 Anthistiria, 63z Anthocarpous, 309, 316 Anthocerotez, 644 Anthocyane, 391 Anthodium, 180 Antholites, 742 Anthotaxis, 172 Anthoxanthine, 391 Anthoxanthum, 631 Anthriscus, 507 Antiaris, 587 Antica, 226 Antidesma, 588 Antilles, flora of, 687 Antirrhinez, 551 Antirrhinum, capsule of, 315 Antitropal, 341 Aperispermic, 343 Apetalz, 560 Apetalous, 367 Apex of fruit, 302 —— of ovule, 253 Aphelandra, 556 Aphthaphytes, 651 Aphyllanthez, 614 Apiacez, 505 Apicilar, 246, 303 Apiculate, 302 Apios, 480 Aplanatic, 762 Aplectrum, 605 Aploperistomi, 643 Aplostemonous, 215 Aplotaxis, 520 Apocarpous, 238, 309 —— dehiscent fruits, 372, ‘i ‘ —— indehiscent fruits, 309 Apocynacez, 536 —— fossil, 755 Apocynum, 537 Aponogeton, 626 Apophysis, 641 Apostasia, 610 Apostasiaceze, 610 Apothecia, 268 Apparatus for drying plants, 795 Apoenaeale: organs, 3o Appendiculate, 218 Apple, 314, 485, 486 Appressed, 111 210, Apricot, 311, 485 Apteria, 610 Aquatic plants, 655 Aquifoliaceze, 599 Aquilaria, 572 Aquilariacez, 572 Arabian flora, 685 Arabin, 163 “Aracez:, 625 Arachis, 480 Araliacez, 509 Arar-tree, 599 Araucaria, 598 Araucarioxylon, 739 Araucarites, 749 Arborescent, 46 Arbor-vitz, 599 Arbutus, 527 Archangelica, 507 Archegonium, 265, 267 Archemone, 626 Archil, 647 Archisperms, 292 Arctic fossil flora, 755, Arctic Region in Bri- tain, 71 Arctic zone, plants of, 9: yeaa 520 Arctostaphylos, 527 Ardisia, 313, 531 Ardtun Leaf-beds, 755 Areca, 621 Arecinez, 621 Arethusa, 604 Argel, 536 Arillode, 329 Arillus, 328 Arinez, 625 Arista, 629 Aristolochia, 577 fertilisation of, 287 Aristolochiacea, 575 Aristotelia, 450 Armeria, 559 Armorican \flora Britain, 708 Arnatto or Annatto, of 439 Arnica, 521 Aroth, 628 Arracacha, 507 Arrow-root, 607 —— starch, 163 Artanthe, 591 Artemisia, 521 Arthrotaxis, 597 Artichoke, 520 Artificial system, 406 Artisia, 741 Artocarpus, 587 Asafeetida, 507 Asagrea, 616 . Asarabacca, 576 Asarum, 576 Ascending’ axis, 44, 334 Ascending sap, 144 Asci, 267 ‘Ascidia, 100 Asclepias, 536 Asclepiadaceze, 534 —fertilisation of, 286 Asclepiadacee, fruit of, 312 Ascomycetes, 649 Ascus, 251 Ash, 533 —— fruit of, 312 Ash of plants, 129, 167 Asimina, 429 Asperula, 512 Asphodelee, 614 Aspidium, 639 Aspidosperma, 537 Asplenium, 639 Assimilation, 124 Astelia, 617 Asteliez, 617 Aster, 520 Asteracez, 517 Asterophyllites, 738 Asters, Region of, 681 Astilbe, 504 Astragalus, 479 Asturian type in Irish flora, 708 Atap, 624 Atherospermacez, 589 Atlantic province, 680 Atractenchyma, 4 Atriplex, 562 Atropa, 549 Atropez, 548 Atropous, 255 Attalea, 622 Attar of Roses, 486 Aubergine, 548 Aucklandia, 520 Aucuba, 510 Aurantiacee, 453 Auricula, 558 Auriculate, 89, 339 Australian flora, 689 Australian Spinach, 56 Autumn Crocus, 616 Avena, 630 Avenia, 83 Averrhoa, 465 Avicennia, 555 Avocado Pear, 569 wn, 224 : Axil, 108, 335 Axil of leaf, 82 Axile, or Axial, 341 Axile placentation, 243 a 82, 98, 108, 174 ASS. ascending, 44,334 —, descending, 37, 334 —, arrangement of flowers on, 172 Azalea, 527 Azolla, 640 Azorella, 509 Azores, plants of, 680 Azotised products, 166 Basut bark, 482 Bacca, 313 Baccate, 313 Bactridium, 649 Baculiform, 272 Bael, 455 Balanophoracez, 577 Balausta, 314, 492 Balm, 554 Balm of Gilead, 475, 599 Balonia, 595 Balsam, bursting of seed-vessel of, 15 —— of Peru, 480 —— of Tolu, 480 — of Umiri, 460 —— trees, Region of, 685 Balsam, bog, 509 Balsamifluz, 504 Balsaminacez, 464 Balsamodendron, 475 Bamboo, 632 Bambusa, 632 Bambusium, 754 Banana, 608 Baneberry, 427 Banisteria, 458 Banksia, 570 fruit of, 152, 312 Banyan, age and size of, 360 Baobab, 449 Baphia, 482 - Baptisia, 480 Barbacenia, 610 Barbadoes Cherry, 458 Gooseberry, sor Barbed hairs, 32 Barberry, 430 — fertilisation of, 83 Bark, 50, 56, 76, 512 Bark-bread, 599 false, in endo- gens, 65 Barley, 630 Barosma, 467 Barringtoniex, 490 Bartsia, 551 Basal placenta, 257 Base of fruit, 302 Base of ovule, 253 Basella, 562_ Bases, organic, 170 Basidia, 269 Basil, 554 Basilar, 247 Bassia, 535 Bassorin, 163 Bast or Bass, 450 Bastard-Cedar, 460 Bast-layer, 57 Batatas, 544 Bauera, 504 Bauhina, 478 ay, 567 ca iearel, 486 Bay-Myrtle, 592 Bdellium, 475 Bean, 479 Bean-caper, 466 Beania, 749 Bearded, 2 Bearded filament, 217 Beaumontia, 537 Beaver-tree, 429 INDEX, Bebeeru, 568 Black Birch, 593 Beech, 595 —— Bryony, 61 Beech-drops, 551 —— Cummin, 428 Beet, 562 — Whortleberry, 526 Beet-sugar, 164 Bladder-nut, 472 Begass, 164 — Senna, 480 Begonia, 566 Begoniacez, 566 Belladonna, 549 Bellis, 520 Bell-shaped, 198, 205 Bengal hemp, 480 Bennettites,750 Ben-nuts, 483 Ben-oil, 483 Bent or marram, 632 Benzoin, 529, 569 Berberidacez, 430 Berberin, 430 Bere or Bigg, 630 Bergamot, 455 Bergia, 443 Berried, 313 Berry, 313 Bertholletia, 492 Berzelia, 504 Beta, 562 Betel-nut palm, 621 Betel-pepper, soz Betula, 593 - Betulacez, 593 Betzal, 615 Bhang, 585 Biennial, 359 Bifid, 202, 248 Bifurcate, 223, 248 Bignoniacez, 540 Bijugate, 92, 104 Biktror Bish, 427 Bilabiate, 207 Bilateral, 248 Bilamellar, 249 Bilberry, 526 Billardiera, 466 Bilobate, 249 Bilocular, 222, 241 Bindweed, 544 Binomial system of nomenclature, 406 Biogenesis, 15 Biparous cyme, 183 Bipartite; 87, 202, 248 Bipinnate, 92 Bipinnatifid, 87 Bipinnatipartite, 87 Birch, 593 Bird lime, 530 Birds, agency in fer- tilisation, 290 Birthwort, 577 Biscuit-root, 615 Bisexual, 212 Bistort, 564 Biternate, 93. Bitter almond, 485 —— apple, 496 —— sweet, 548 — wood, 430 Bivalvular, 303 Bixacez, 439 Bizarres, 445 Black Alder, 472 —— wort, 557 Blade of leaf, 82 Blaeberry, 526 Blanching, 397 Bleeding, or flow of sap, 144 Blessed Thistle, 520 Bletting, 322 Blighia, 459 Blight, 399 Blood-root, 434, 610 Bloom of Grapes, 168 Blume’s Floral Re- gion, 684 Boards for pressing plants, 798 Bocagea, 429 Boehmeria, 584 Boerhaavia, 561 Bog-bean, 540 —— mosses, 643 —— myrtle, 592 Bolax, 509 Boldoa, 589 Boletus, 649 Bolivaria, 532 Bombacez, 448 Bombax, 449 Bonapartea, 612 Bone-earth, 138 Bones as a manure, 139 Bonnetia, 452 Bonpland’s Floral Re- gion, 686 Boopis, 517 Borage, 546 Boraginacee, 545 —— fruit of, 31x Borassinez, 621 Boronia, 467 Boswellia, 475 Botanical box, 796 — spade, 796 — terms explained, 809 Botany Bay Kino, 491 Bothrenchyma, or Taphrenchyma,6, 20 Bothrodendron, 734 Botnim, 474 Botrychium, 639 Botrytis, 650 Bottle Gourd, 496 Bourdeaux Pine, 599 Bovista, 650 Bowenia, 600 Box-tree, 582 Brachychiton, 449 Brachyphyllum, 748 Bractez, 189 Bracteoles, 177, 189 Bractlets, 177, 189 Bracts, or floral leaves, 172, 1 — arrangement of, 190, 3H 833 Bracts, coloured, 189 —— empty, 189 —— phyllotaxis 189 —— _ viviparous, proliferous, 191 Bramble, 312, 485 Branches, 112 —~ arrested, 119 Branching of trees, 45 Branchlets, rr2 Brassica, 437 Brassicacez, 434 Brayera, 486 Brazil-nuts, 492 — wood, 481 Brazilian flora, 687 Bread-fruit, 316, 587 —— nuts, 587 —— tree, 601 Brexia, 504 Brinjal, 548 Britain, distribution of plants in, 702 British plants, ities of, 703 —— types of, 703 . — sporadic species of, or local- 709 Brocoli,. 437 Bromelia, 612 Bromeliacez, 612 Bromus, 632 Brongniart’s division of fossil plants, 721, 727 Brookweed, 559 Broom, 480 Broom-rape, 550 Brosimum, 587 Broussonetia, 587 Brown coal, 757 Brown’s floral Region, 689 Brownian corpuscles, 293 Brucea, 469 Bruniacez, 504 .Brunoniacez, 522 Bryacez, 641 Bryonia, 494 Bryony, 496 Bryophyllum, 499 Bryson’s _ instrument for slicing fossils, 788 Bryum, 643 Buchu, 468 Buck-bean, 540 — eye, 459 Bucklandia, 504, 750 Buckthorn, 472 Buckwheat, 564 Bud, arrangement of leaves in the, 112 ‘Budding, 109, 325 Buds, leaf, ro’ —— abnormal, 40 —— adventitious, 117 — embryo, 116 — flower, 193 —— latent, 112, 117 834 Buds, on grasses, 358 ——on leaves, 118, 35: —— separable, 357 —— suppression 368 Buffalo-tree, 574 Bugle-weed, 554 Bugloss, 545 Bukkum-wood, 482 Bulb, 114 — pseudo, 47 —— naked, 115 — scaly, 115 — solid, 116 — tunicated, 115 Bulblets or bulbils, 117 Bulbochzte, 270 Bull-palm, 622 Bulrush, 625 Bunch-grass, 631 Bunias, 435 Bunium, 507 Bunt, 399 » 520 of, Burdoc! Burgundy pitch, 599 Bunti-palm, 622 Burmanniacez, 610 Bursaria, 466 Burseracez, 475 Bush, 46, Butea, 480 Butter of Cacao, 450 — of Canara, 457 — tree of Park, 531 Butomacez, 623 Butomus, 623 - — fruit of, 312 Butterfly-weed, 536 Butter-nuts, 453 — of plants, 168 — tree, 531 Butterwort, 557 Buxus, 582 Byttneriacezx, 449 CABBAGE, 437 — fruit of, 315 — palm, 621 — tree, 480 Cable-cane, 622 Cabomba, 432 Cabombez, 432 Cacao, 450 Cactacez, 500 — Region of, 686 Caducons, 199, 211 Cesalpinia, 478, 481 Cesalpiniez, 481 Czsarea, 463 ein, 514 Cajuput, 497 Calabar bean, 329, 481 Calabash-tree, 541 Caladium, 625 Calamander wood, 528 Calamites, 736 Calamodendron, 745 Calamus, 622 Calandrinia, 446 Calathea, 607 Calathium, 182 INDEX. Calcar, 198 Calcarate, 198, 202 Calceolaria, 551 — Region of, 686 Calceolate, 207 Calcophyllum, 514 Caliculate, 190, 198 California and Oregon flora, 682 Calla, 625 Callitriche, 493 Callitris, 599 Calluna, 527 Calonyction, 545 Calophyllum, 456 Calotropis, 536 Calumba, 430 Calvary plants, 479 Calycanthacez, 487 Calyceracee, 515 Calyciflorz, 214 Calyciflore Gamope- talz, 510 Calycifloree Polypeta- le, 470 Calycine hairs, 197 Calyptra, 641 Calyptrate, 199 Calyptrimorphous, too Calystegia, 544 Calytrix, 491 Calyx, 191, 195, 198 —— degenerations in, 196, 198 Cambium, 56, 75 Cambogia, 456 Camellia, 453 Camel’s-thorn, 479 Camera-lucida, 772 Campanula, style of, 290 Campanulacee, 524 Campanulate, 205 Campeachy-wood, 482 Camphor, 169 Camphora, 568 Campion, 445 Camptopteris, 747 Camptotropal, 255 Campylosperme, 506 Campylotropal, 255, 330 Camwood, 482 Canada Balsam, 599 — Rice, 631 Canarium, 475 Canary Islands, flora of, 680 Canary-seed, 631 Candleberry, s92 Candle-nut-tree, 582 Candle-tree, 54: Candollea, 428 Cane-sugar, 164 Canella-bark, 439 Canellacez, 439 Canker, 399 Canna, 607 Cannabis, 584 Cannabinacee, 584 Cannacez, 606 Canoe-birch, 593 Caoutchouc, 170, 537 Cape Gooseberry, 549 Caper-spurge, 582 Capers, 438 Capillaire, 639 Capitate hairs, 32 Capitula, 182, 191 Capitulum, 180, 182 Capoeira, 346 Capparidacee, 437 Caprification, 264 Caprifoliacez, 510 Capsicum, 548 Capsule, 315 Carapa, 460 Caraway, 508 Carbon in plants, 126 Carbonate of potash and soda as a man- ure, I Carbonic acid decom- posed by aquatics, 158 5 Carbonic acid given off by flowers, 259 Carboniferous fossils, 729 ; Cardamoms, 606 Cardiocarpum, 746 Cardoon, 520 Carduus, 520 . Carex, 628 Carica, 497 Carices, province of, 79 Carina or Keel, 205, 506 Carinal, 195 Carludovica, 624 Carnahuba palm, 622 Carnation, 445 Carob-tree, 481 Carpel, 235, 238, 239, 303 Carpels, number and position of, 238 — analogy to leaves, 235 Carpolithes, 746, 750 Carpology, 308 Carpophore, 240, 305, 3II Carrageen, 655 Carrion flowers, 536 Carrot, 507 Carthamus, 520 Cartilaginous albu- men, 333 Carya, 596 Caryocar, 453 Caryophyllacee, 444 —— Region of, 680 Caryophyllaceous cor- olla, 204 Caryophyllus, 49x Caryopsis, 311 Caryota, 622 Caruncules, 329 Cascarilla bark, 582 Casearia, 573 Case for microscopic slides, 792 Casein, vegetable, 166 Cashew, fruit of, 310, 473 Casparya, 566 Cassava, 582 Cassia, 478, 481 — bark and buds, 5' Cassipourea, 488 Cassowary-tree, 593 Cassytha, 567 Cassythez, 567 Castanea, 595 Castor-oil, 58x Casuarina, 593 Casuarinaceze, 593 Catechu, 482 Catha, 471 Cathartocarpus, 481 —— Fistula, fruit of, 308 Catingas in Brazil, 123 Catkin, 178, 190 Caudate, 310 Caudex, 44 Caudicle, 229 Caulescent, 44 Caulicle, 334 Cauliflower, 437 Caulinary, 97 Cauline, 362 Cauline leaves, ror Caulinia, 626 Caulis, 44 Caulopteris, 732 Cavernous tissue, 81 Cayenne-pepper, 548 Ceanothus, 472 Cecropia, 588 Cedar, 598 Cedars, age and size of, 360 —— cone of, 317 Cedrelacez, 460 Cedrus, 598 Celandine, 433 Celastraceze, 471 ——, Region of, 682 Celery, 507 Cell development, z3 —— germ, 275 —— nucleus, 9 Cells, 3, 7, 241 —— contents of, 8 —— endosperm, 293 —— epidermal, 27 —— functions of, 13 —— movements in, I51 — of ovary, 299 —— prepared for microscopic prepa- rations, 786 Cellular, 3 Cellular plants, propa- gation of, 14 Cellular tissue, 3 Cellulares, 638, 644 Cellulose, 1, 8 Celosia, 562 Celtideze, 585 Celtis, 585 Centaurea, 520 Centrifugal, 175 Centripetal, 175 Centrolepis, 627 Cephaelis, 513 Cephalanthus, szr2 Cephalotaxus, 598 Cephalotez, 503 _Cephalotus, 503 Ceradia, 521 Ceramium, 654, Cerasin, 163 Cerastium, 445 Cerasus, 486 Ceratium, 649 Ceratonia, 478 Ceratophyllacez, 588 Cerbera, 537 Cereal grains, distribu- tion of, 668 — — fertilisation in, 113, 284 Cereals, albumen of, B33 3 Cereus, sor Ceroxylon, 622 Cestrum, 548 Cetraria, 646 Cevadilla, 616 Ceylon flora, 683 Ceylon moss, 655 Chzrophyllum, 507 Chailletiaceze, 572 halaza, 255, 329 Chalk fossils, 750 Chalmugra or Cia mugra, 440 Chamzlauciez, 490 Chameerops, 622 Chamisso’s floral Re- gion, 684 Chamomile, 520 Chandelier-tree, 624 Channel Island flora, 706 Chara, 651 Chara, carbonate of lime in, 132 rotation in, 152 Characez, 651 fossil, 754 —— reproduction in, 274 Charcoal as a manure, 139, Charianthus, 489 Chatzir, 615 Chavica, 591 Cheirostemon, 449 Chelbenah, 507 Chelidonum, 433 Chemical agents, ef- fects on movements of plants, 387 Chemical composition of plants, 124 — composition of soils, 134 elements, 124 Chenopodiacez, 562 Chenopodium, 562 Cherimoyer, 430 Cherry, 321, 486 INDEX, Cherry, double flower- Ing, 236 —— laurel, 486 Chervil, 507 Chestnut, 595 Chestnut, fruit of, 3:2 Chian Turpentine, 474 Chick-pea, 479 Chickweed, 444 Chicory, 522 Chili-nettle, 493 Chillies, 548 Chimaphila, 527 himonanthus, 487 China bark, 513 —— root, 617 Chinese flora, 682 —— grass-cloth, 58. Chinanthus, 533 : Chiretta, 540 Chironia, 539 Chive, 615 Chlenaceze, 451 Chloranthaceze, 590 Chloranthus, 590 Chlorophyll, 12, 168, 258, 390 Chlorosporez, 653 Chloroxylon, 460 Chocolate, 450 Chondodendron, 430 Chondrites, 751 Chorda, 654 Chorisation, 371 Chorisis, 210, 365 Choristosporei, 653 Christison on fossil trees, 789 Christmas rose, 427 Christ’s-thorn, 473 Chromatic aberration, 763 Chromatometer, 390 Chromogen, 392 Chrysanthemum, 521 Chrysobalanez, 483 Chrysophanic acid, 647 Chrysophyll, 392 Chrysophyllum, 532 Chrysosplenium, 504 Churrus, 585 Chusan Han-tsi, 562 Cibotium, 640 Cicatrices on ferns, 72 Cicatricula, 82 Cicatrix, 95 Cichoracez, 519 —— province of, 680 Cicuta, 508 Cilia, 204, 205, 235, 265 Ciliated hairs, 33 Cimicifuga, 427 Cinchona, 512 —— glands, 35 Cinchonacee fossil,755 Cinchonas, or Medi- cinal barks, Region of, 686 : Cinenchyma, 21 Cinenchymatous, 146 Cinnamodendron, 439 Cinnamomum, 568 Cinnamon, 568 Circaea, 493 Circinate, r10, 339 Circular, 194 Circulation of fluids in Plants, 124, 142, 147 Circumscissile, 226, 307 Circumscription of leaf, 82 Cirrus, 97, 120 Cissampelos, 430 Cissus, 46x Cistacez, 439 Cistuses, province of, 680 Cistus-rape, 577 Citron, 454 Citrus, 454 Cladenchyma, 4 Cladium, 628 Cladocarpi, 643 Cladonia, 647 Cladosporium, 651 Classes, essential char- acter and nomencla- ture, 411 — of plants, 405 Classification, artificial and natural, 406 —— systems of, 405, 418, 422 Clavaria, 649 Clavate, 217 — hairs, 32 Claviceps, 650 Claw, 201 Claytonia, 446 Clearing-nut, 539 Cleft-grafting, 325 Clematidez, 426 Clematis, 427 Cleome, 438 Clerodendron, 555 Clianthus, 479 Climate, effect of, on flowering, 667 Climbing plants, 385 Clinandrium, 230 Clinanthium, 173 Clintonia, 525 Close interbreeding, prevention of, 286 Ciosing of flowers, 262 Clove, 491 Clove pink, 445 Clover, 479 Cloves, 114, 358 Club-moss, 640 Club-mosses, embryo- geny in, 278 : Clusiacez, 456 Cluster-pine, 599 Cnestis, 476 Coal epoch, climate of, 742 —— flora of, 743 Coal-measures, plants Ol, 730 Coal of Humus, 134 835 Coal, sporangia in, 729 Cobea, 542 Coca, 457 Cocci, 306 Coccoloba, 565 Cocculus, 430 Cochlearia, 437 Cochleariform, 202 Cochineal-Cactus, 502 Cockscomb, 173, 562 Cocksfoot-grass, 631 Cocoa, 450 Cocoa-plums, 485 Cocoinez, 621 Coco, 621, 625, Coco-nut, 621, 291 — albumen of, 333 Ccelosperme, 506 Coffea, 514 Cohesion, 365, 369 Coiling of tendrils, 385 Coir-rope, 621 Coix, 632 Colchicez, 616 Colchicum, 616 Coleorhiza, 42, 336 Coleseed, 437 Collateral, 257 Collecting hairs, 33 Collectors in foreign countries, directions to, 806 Collemacez, 646 Collenchyma, 8 Collomia, 542 —— spiral cells in seeds of, 327 Collum, 38, 334 Colocasia, 625 Colocynth, 496 Coloquintida, 496 Colouring matters, 171 Colours, complement- ary, 396 — of flowers, 393 —— in natural orders, 395 Gclaenchyma: 4 Colt’s foot, 520 Columbine, 202 Columella, 304 Columelliacez, 532 Columna, 219 Columnea, 541 Colutea, 480 Colza, 437 Combretacez, 488 — fossil, 754 Commelynacez, 622 Commissure, 321 Composite, 517 —— fruit of, 310 —— arborescent, Re- gion @f, 687 Compound, 235, 239 — leaves, 85, 9r Compressed, 330 Compressorium, 772 Comptonia, 592 Conantherez, 614 Conceptacles, 268 836 Concrete oils, 167 Condenser, 765 Conducting tissue, 236 Conduplicate, 111, 193, 339 Conenchyma, 4 Cones, 179, 190 — spirals in, 105 Conferva, conjugation of, 21 — reproduction of, 272 Conferve, 655 Conia, 508 Conidia, 267 Coniferze, 596 — fertilisation in, 291 — fossil, 746 — fruit of, 317 — of chalk, 75x Coniomycetes, 648 Coniothalamez, 646 Conium, 508 Conjugate, 266, 654 Conjugation, 653 Connaracee, 476 Connate, 100 Connective, 221, 224 Connivent, 197 Conservatory, 349 Conservatory, Ward’s portable, 160 Contorted, 40 Contortive, 111, 193 Contrayerva, 587 Convallariez, 614 Convergent, 84 Convolute, 111, 194, 339 Convolvulaceze, 542 Convolvulus, 544 Copaifera, 482 Copaiva, 482 Copalchi bark, 582 Copper-coloured trees, 392 Copper in plants, 132 Coptis, 427 Coquilla-nuts, 622 Coral-flower, 479 Corallina, 654 Coralline, 40 Corchorus, 450 Corculum, 335 Cordate, 89, 203 Cordiaceze, 545 Cordilleras, flora of,686 Cord-Rush, 627 Cordyline, 616 Corema, 579 Coriander, 508 Coriariaceze, 470 Cork, 58, 595 Cony layer of bark, 5 Corm, 48, 115 Cormogenz, 638 Cornaceze, 509 Corn-plants, ‘distribu- tion of, 668 Cornus, 510 “INDEX. Corona, 209 Corolla, 199, 200 —— irregularities in, 211 Corolliflorz, 526 Corollifloral, 214 Corolline appendages, 210 : —— hairs, 34, 201 Coronet, 210 Coronilla, 48x Corpuscles of Brown, 293 Correa, 467 Corrigiola, 499 Corrugated, 193, 203 Corsican Moss, 655 Cortical system, 56 Corydalis, 434 Corylacez, 594 Corylus, 595 Corymb, 178 Corymbiferze, 518 Corynophallus, 626 Coryphinee, 621 Coscinium, 430 Costate, 84 Cotton, 16, 33, 448 Cotton-grass, 628 Cotyledon, 500 Cotyledons, 101, 331, 45, 33! ae Tolding of, 339 — of Welwitschia, 338 —— verticillate, 338 Couch-grass, 631 Couratari, dehisence of fruit of, 307 Coverings of the seed, 326 Cowbane, 508 Cowberry, 526 Cowitch, 480 — hairs of, 33 Cow-plant, 536 Cowslip, 558 Cow-tree, 537, 587 Cow-wheat, 532 Cranberry, 526 Cranes-bill, 462 Crassula, 499 Crassulacez, 499 —— fruit of, 312 Craterium, 649 Credneria, 750 Cremocarp, 305, 312 Crenate, 86 Crescentia, 541 Crescentiez, 540 Cress, 436 ' —— fruit of, 315 Crested, 2or Crests, 224 Cretaceous flora of England, 709 Cretaceous fossils, 750 Creyat, 556 een 611 TISP, 90, 203 Crithmum, 507 Crocus, 609 — seed of, 329 _ Crops, nutritive “pro- ducts of, 167 —— rotation of, 133 Crosses, 297 Croton-oil, 58x Crowberry, 579 Crowfoot, 426 Crown grafting, 325 Crown Imperial, 615 Crown of the root, 37, 46, 113 Crozophora, 583 Cruciferze, 306, 434 —— divisions of, 340 —— fertilisation in, 28 4, Region of, 686 Cruciferous corolla, 205 Cryptocarya, 569 Cryptogamic repro- duction, organs of, 233 Cryptogamous, 171 —— plants, 635 —— — , fertilisation in, 266 —— —, pistillidia, 250 —— — spores, 258 Crystals in cells, 10 Crystalworts, 644 Ctenis, 747 Cuba Bast, 448 Cubeba, sor Cubeb-pepper, s9z Cuckoo-pint, 625 Cucullate, 250 Cucumber, 495 —— squirting, 343 Cucumis, 494 Cucumites, 751 Cucurbitacez, 314, 494 Cudbear, 171, 647 Culm, 44 Cultivation, effect on organs of the flower, 374 Cumin, 508 Cuneate, 89 Cunninghamia, 598 Cunoniez, 503 Cupania, 459 Cupanoides, 751 Cupressinez, 598 Cupula or cup 190, 311 Cupulifere, 594 Curcas, 582 Curculigo, 612 Curcuma, 606 Currant, 313, 502 — of Australia, 528 Currants or Corinths, 462 Curved radicle, 340 Cuscuta, 545 Cuscuteze, 544 Cuscus or 632 Kuskus, Cusparia, 468 Cuspidate, 202 Cuspis, 202 Cusso, 486 Custard-apple, 429 Cutch, 482 Cuticle, 25 ae series of co- jours, 393 Cyathea, 639 Cycadacez, 600 —— fertilisation in, 291 — fossil, 746 —— of chalk, 751 Cycadeostrobus, 750 Cycadinocarpus, 746 Cycadites, 750 Cycas, 601 Cyclamen, 558 Cyclantheze, 624 Cyclanthus, 624 Cyclogens, 53 Cyclosis, wae Cydonia, 486 Cylindrenchyma, 4 Cytinacez, 577 Cymbiform, 202 Cyme, 182 Cyme, biparous, 183 — contracted bi- parous, 184 —- contracted scor- pioid, 187 ——- dichotomous, 183 —— helicoid, 185 —— racemose parous -—— scorpioid, 185 —— trichotomous, 183 —— uniparous, 183, Cynanchum, 536 Cynara, 520 Cynarocephale, 518 Cynarrhodum, 310 Cynodon, 631 Cynoglossum, 546 Cynomorium, 577 Cynosurus, 632 Cyperaceze, 687 Cyperus, 628 Cypress, fruit of, 317 Cypsela, 320 Cyrtandrez, 540 Cyst, 12 Cystidia, 268 Cystocarp, 272 Cystolith, 10, 12 Cytisus, 478, 481 Cytoblast, 13 Cytoblastema, 8 Cytogenesis, 13 Cyttaria, 649 uni- DaseEocia, 527 Dactylis, 631 Dadoxylon, 739 Dedalenchyma, 4 Dezmonorops, 622 Daffodil, 611 Dahlia, 374 Dalbergia, 478 Dammara, 599 ammar resin, 451 Dampiera, 52 Danza, 639 Dandelion, sar Daphne, 572 Daphnez, 577 Dardar, 467 Darkness, effect on flowers, 263 —— in germination, 34 Darlingtonia, 433 insects in pit- chers of, 384 Darnel-grass, 632 Date, 311 Date-palm, 621 Datisca, 578 Datiscacez, 578 Datura, 549 Daucus, 507 Davallia, 640 Day-lily, 614 Deadly-nightshade, 549 : De Candolle’s classi- fication, 418 * —— floral Region, 680 Decandrous, 216 Decayed leaves, co- lours of, 392 Deciduous leaves, 83 Declinate, 228 Decompound, 92 Decurrent, too Decussate, 102 Deduplication, 365, 372 Definite, 257 —— inflorescence, 175, 182 —— stamens, 216 Defoliation, 123 Degeneration, 365, 369 Degradation, 368 Dehiscence, 225, 303, 210, 210, 305 i Dehiscent fruits, 303, 309, 312 Delesseria, 654 | Delile’s floral Region, 685 Delima, 428 Delphinium, 427 — fruit of, 312 Dendrobium, 604 Dentate, 86 Deodar, 598 Depressed, 330, Descending axis, 334 sap, 144, 146 Desert Region, 685 Desmidiezx, 654 --— reproduction of, 269 Desmodium, 377, 482 Detarium, 477 Determinate Inflores- ence, 175 Deutzia, 490 INDEX. Dextrin, 163 Dhak tree, 480 Dhoom pitch, 451 Diachenium, 311 Diachyma, 80 Diadelphous, 218 Dialycarpous, 309 Dialypetalous, 203 Dialysepalous, 196 Diandrous, 216 Dianthus, 445 Diapensiez, 542 Diastase, 165 Diataxis, 406 Diatomacez, 654 | Diatoms, preparation of, 79% —— reproduction of, 269 Dicentra, 434 Dichlamydeous, 192 Dichogamous plants, fertilisation of, 286 Dichopetalum, 509 Dichotomous cyme, I Diclinous, 367 Dicotyledonous, 334 -—— embryo, 336, 362 —— germination, 356 —— plants, symmetry in, 364 Dicotyledons, leaves of, 107 —— root of, 41 Dicranum, 643 Dictamnus, 467 Dictyogens, 60r Dictyoxylon, 742 Didymocarpez, 540 Didynamous, 228 Dieffenbachia, 685 Dielytra, 434 Diervilla, 511 Digestion of plants, 100 phyllotaxis of, 156 Digestive fluid in pitchers, 384 Digger for plants, 790 Digitaliform, 206 Digitalis, 552 —— fruit of, 315 Digitate, 93 Digitipartite, 87 Dilamination, 210, 371 Dill, 508 Dilleniacez, 428 Dimerous, 363 Dimorphic, 212, 285 — plants, fertilisa- tion in, 284 — sporangia, 278 Dicecious, or dioicous, 212, 273, 36) —— plants, tion in, 284 Diceciously - hermaph- rodite, 285 Dioicous, 212 7 fertilisa- Dion, 60x Dionea, 441 —— muscipula, irrita- bility in, 380; Dioscorea, 611 Dioscoreaceze, 610 Diosma, 467 Diospyros, 528 Diphylleia, 43x Diplecolobez, 435 Diploé, 80 Diploperistomi, 643 Diplostemoneus, 215 Diplozygiz, 506 Dipsacacee, 515 —— fruit of, 310 Dipterix, 480 Dipterocarpacez, 451 Dipterocarpus, 451 Dirca, 572 Disa, 604 Dischidia, 536 Disciform, 53 Discoid, 53 Discomycetes, 649 Discs, 17, 268 Disease, potato, 398, 402 Disease, vine, 403 Diseases of plants, 397 —— of plants caused by insects, 4o2 Diserneston, 507 Disk, 234 Dissected, 87 Dissemination of plants 668 Dissepiment, 241 —— spurious, 244 Dissilient, 306 Distichous, 103 Distractile, 224 Distribution of plants from centres, 672 Dithecal, 222 Dittany, 468, 554 Divergent, 84, 197 Divi-divi, 481 Dockhan, 631 Dodder, 544 — spiral embryo of, 340 — suckers of, 40 Dodecandrous, 216 Dodecatheon, 558 Dodonea, 459 Dogbane, 536 Dog’s-tail grass, 631 Dog-tooth violet, 614 Dolabriform, 90 Dombeya, 450 Doom-palm, 622 Dorema, 507 Dorsal, 340 Dorsiferous ferns, 639 Dorstenia, 181, 310, 5°7 —— fruit of, 317 Dotted vessels, 20 Double coco-nut, 621 Double flowers, 214, 236, 369 r 837 Draba, 435 Draczna, 615 Dracontium, 686 Dragon’s- blood, 615, 622 Draining, 347 Drimys, 429 Droseracez, 441 —— irritability in, 380, 382 Drosophyllum, 441 Drupacez, 483 Drupe, 311 Drupels, 312 Dryandra, 570 Drying oils, 167 — paper, 797 —— plants, mode of, 799 Dryobalanops, 451 Dry rot, 141, 401, 650 Duckweed, 626 Ducts, closed, 19 Dudaim, 549 Dudresnaya, _repro- duction in, 273 Duguetia, 429 Dulse, 655 Dumb-cane, 625 Dumose, 46 Duramen, 55 Durian, 449 Durmast, 595 Durra, 631 Durvillea, 654, 70r D’Urville’s Region, C6 e Dust-brand, 399 Dutch-rushes, 637 Dwale, 549 EAGLE-wooD, 572 Ear-cockles, purples or pepper-corn, 403 Earth-nut, 312, 507 Ebenacee, 528 Ebony, 528 Ebracteated, 189 Ecballium, 496 Eccremocarpus, 540: Echinate, 284 Echinocactus, 502 Echites, 537 Echium, 546 Ectocarpus, 654 Eddoes, 686 Edible nests, 655 Egg-apple, 548 =— Plant, 495 Ehretia, 546 Elaborated sap, 144 Eleagnacez, 570 Elezagnus, 571 Elzocarpez, 450 Elzodendron, 471 Elaia, 533 Elais, 621 Elaphrium, 476 Elaterium, 496 Elaters, 643 Elatinaces, 443 Elder, 511 838 Elecampane, 520 Elemi, 475 Elephant’s-foot, 611 Elettaria, 606 Elm, 585 —— fruit of, 31z Elodea, 456, 602 Elymus, 631 Elyna, 628 Emarginate, 89, 202 Embryo, acotyledon- ous, 335 — buds, 116 — curved or amphi- tropal, 342 —— dicotyledonous, 337 —— erect or homotro- pal, 342 —— fixed, 109 — formation of, 330 —— inverted or anti- tropal, 341 —— macropodous, 336 — monocotyledon- ous, 336 —— of coco-nut, 333 —— plant, 298 — plants, parts of 334 —— polycotyledonous, 8 33: —— position and form of, 340 —— sac, 253 —— sac of Yew, 292 Embryogenic process in gymnospermous flowering plants, 291 —— process in angio- sperms, 294 Embryonal cell, 276 Embryonal corpuscles in coniferous seeds, 332 : Embryonal _ vesicles, 293 Embryonary sac, 332 Embryotega, 329 Emetin, 513 - Emodic Region, 683 Empetracee, 579 Empetrum, 579 Empty bracts, 189 Emulsin, 166 Encephalartos, 601 Endemic plants, 670 Endlicher’s classifica- tion, 419 Endocarp, 300 Endochrome, 266 Endogenz, 601 Endogenous or monoco- tyledonous stem, 64 — plants, course of sap in, 148 Endophleeum, 57 Endopleura, 327, 328 Endorhizal, 42, 356 Endosmometer, 143 Endosmose, 15, 142 Endosperm, 293, 332 INDEX. Endospermic albumen, 332 Endostome, 254 Endothecium, 220 English Mercury, 562 Enneandrous, 216 Ennobling, 325 Ensiform, 90 Entire, 86 Entephyac fungi, 400 Envelopes, floral, 192 — functions of, 258 Eocene flora, 753 — flora of Europe, ae Epacridacez, 527 —— Region of, 689 Epacris, 528 Ephedra, 598 Ephemeral, 262 Epiblast, 337 Epiblema, 26, 38 Epicalyx, 189, 198 Epicarp, 300 Epichilium, 602 Epidendrum, 604 Epidermis, 26 —— appendages of, 30 —— of leaf, 79 — papillee of, 30 — silica in, 28 -—— special functions of the, 36 —— wax on, 28 Epigeal, 356 Epigynous, 213, 246 — disk, 235 Epilobium, 493 Epimedium, 432 Epipetalous, 213 Epiphagus, 55: Epiphleeum, 57 Epiphragm, 642 Epiphytes, 39, 14r Epirrheology, 657 Episperm or testa, 32) Epithelium, 26, 236 qual, 86 Equally pinnate, 93 Equisetaceze, 636 — embryogeny in, 281 Equisetites, 745 Equisetum, 637 — fossil, 748 — silica in, 131 Equitant, 112, 340 Erect, 224, 257, 330, 342 Eres, 598 Ergot, 400 —— of rye, 634 Erica, 527 —— fertilisation 289 Ericacez, 526 Ericez, province of, in, 68: Eriobotrya, 486 Eriocaulon, 627 Eriogonez, 564 Eriolzna, 450 Eriophorum, 628 Eriospermez, 614 Eryngium, 507 Eryngo, 507 Erysiphe, 649 Erythrza, 540 Erythrina, 479 Erythrinum, 614 Erythrophyll, 391, 392 Erythroxylacez, 457 Escallonia, 503 Escalloniex, Region of, 686 Eschscholtzia, 433 Essences, 168 Essential characters of classes, 411 — oils, 168 —— organs, 192 —— organs, Phanero- gamous plants, 264 —— organs of repro- duction, 212 Eterio, 312 Etiolation, 162 Eucalypti, Region of, 68 Eucalyptus, 491 Eugenia, 491 Eulophia, 605 Euonymus, 471 Eupatorium, 520 Euphorbia, 581 — fertilisation of, 287 Euphorbiacee, 579 —— fruit of, 315 Euphrasia, 551 Euphrasia, fertilisation in, 290 European palm, 622 | Euryale, 432 Euryangium, 508 Eutassa, 598 Euterpe, 621 Eutoca, 542 Evening Primrose, 492 Evergreen Beech, 595 —— leaves, 83 —— Oak, 595 Evernia, 646 Exalbuminous, 332 Exannulate ferns, 639 Excentric, 56 Excrescences, 116 Exhalation, 121 Exidia, 650 Exintine, 230 Exogene, 425 Exogenous or Dicoty- ledonous stem, 49 —— fossil stem, 758 —— stem, anomalous, 60 —— stems, course of sap in, 144 ee in elds, 73 — Wascalae bundles, coal- 53. Exogonium, 544 Exorhizal, 41, 357 Exosmose, 15, 142 Exostemma, 513 Exostome, 254 Exothecium, 220 Expansion of flowers, 174 Exserted, 227 Exstipulate, 97 External or extra- rius embryo, 340 Extine, 230 Extra-axillary, 116, 174 Extrorse, 226 Eye-bright, 582 Eye-piece of micro- scope, 765 Eyes of Potato, 47 Ezrach, 567 FaBAceEsé, 476 Fagopyrum, 564 Fagus, 595 Pay: Rings, 401, 650 Falkland Islands, flora oO. > Fall of leaves, 123 Families, 410 Fan-Palm, 622 Farinaceous or mealy albumen, 333° Fasciated, 117 ‘| Fascicle, 184 Fascicled leaves, 369 Fasciculate, 40, 107 Fat oils, 167 Fatsia, 509 Faux, 204 Feather-veined, 86 Fecundation, 264 in cryptogams, 2 in phanerogams, 201 Fenestrate, 82, 316 Fennel, 507 — flower, 428 Ferns, 637 7 —— embryogeny in, 281 — in coal measures, 730. Feronia, 455 Fertile, 368 Fertilisation, 264 _ —— agency of birds in, 290 —— by insects, 284 —— heteromorphic, 285 — homomorphic, 285 — in angiospermous flowering plants,.294 —— in Aristolochia, 287 — in cereal grains, 284 —in conifere and cycadacez, 291 Fertilisation in crypto- gamous plants, 266 — in dichogamous plants, 286 —— in Erica, 289 — in Euphorbia, 287 — in Euphrasia, 290 — in Fumariacez, ae ‘eer TA gymnosperms, 291 — inj kidney-bean, 288 —- in moneecious, dicecious, and dimor- phic plants, 284 in orchidaceze and asclepiadacez, 286 — in Parnassia, 286 — in phanerogams, 281 in Polygala, 289 —— in Primroses, 285 -— in Pringlea, 284 - in Rhinanthus crista-galli, 290 —in Scrophlularia- cezand Labiate, 289 — in sea-pink, 291 — object of, 330 — self, 284 Ferula, 507 Fescue, 631 Festuca, 632 Fever-bush, 569 Feverfew, 520 Fevillea, 494 Fibre in spiral ves- sels, 18 Fibrils, 38 Fibrin, vegetable, 166 Fibro-cellular tissue, 6 Fibrous root, 40 tubes, 16 Fibro-vascular tissue, 7 - Ficoidez, 500 Ficus, 586 . Field-book, 796 — for drying plants, 6 79 Fig, 181, 310, 317, 586 —— marigold, 500 Figwort, 552 Filament, 216 Filbert. See Hazel, 311-595 Filices, 637 Filmy fern, 639 Fimbriated, zor Finochio, 507 Fir, 597 — cone of, 317 Fissiparous, 267 separation of cells, 14 Fissures, 86 Fistular, 100 Fitches, 427 Fitzroya, 598 Fixed embryos, 109 INDEX. Fixed oils, 167 Flabellaria, 742 Flacourtia, 440 Flag, 628 Flagellum, 113 Flakes, 445 Flax, 16, 463 — New Zealand, 16 — Pita, 16 Fleshy cotyledons, 33 — leaves, colours of, 392 bic Be — or cartilaginous, 333 Fleerkea, 465 Flora’ of Paleozoic period, 728 — of Polynesia, 684 —— of Secondary or Mesozoic period, 745 —,of Tertiary or Cainozoic ‘ period, 750 Floral axis, 173 — calendar, 261 — envelopes, 192 — envelopes, de- velopment of, 211 — envelopes, func- tions of, 258 — leaves, ror, 189 — watch or clock, 262 — whorls, «inner, 2Ir Floras of Britain, their origin, 710 — of islands, 673 Flor de coco, 389 Florets, 187 Florida, Mississippi, and Carolina, flora of, 681 Floridez, 653 —— reproduction in, 273 Flower, arrangement on the axis, 172 —— bud, 193 Flower, position of its parts, 195 Flowering, 359 —— ash, 533 — mode of accele- rating, 261 —— period of, 26x — plants, fertilisa- tion in, 282 — Rush, 623 Flowerless plants, 266 Flowers, double, 369 —— causes of want of symmetry, 365 — effect of light and darkness on, 263 Flowers, movements in, 386 — odours of, 396 —— transformation of parts of, 369 Fluid, absorption and circulation of, 142 in exogenous plants, course of, 146 — in plants, rate of movement, 154 —— matter in endoge- nous plants, 148 — special move- ments of, 151 Fluorine, 131 Flute grafting, 325 Foliaceous, 197, 339 Foliar, 362 Foliola, 86, 91, 195 Follicle, 312 Folliculites, 754 Food of plants, 124 — value of certain matters for, 167 - Fool’s Parsley, 508 Foramen, 254 Forbes’ flora of Bri- tain, 708 Forbidden fruit, 454 Forget-me-not, 547 Forked, 223, 237 — style, 248 Fork-veined, 84, 85 Fornasinia, 481 Forskal's floral Region, 685 Forstera, 523 Forster’s floral Region, OL Fossil acrogens, reign of, 728 —— botany, 718 —— botany, works on, 5 a ioe of carboni- ferous system, 729 flora of Silurian and Cambrian sys- tem, 728 —— genera and spe- cies, 724 —— plants, determina- tion of, 720 —— plants in different strata, 726 -—— plants, mode of preservation, 719 — plants, nomencla- ture of, 722 — plants, number of, 726 : —— plants of Chalk Epoch, 750. — plants, orders of, 725 . —— plants, sections of, 7°7 : — plants, their classes, 721 Fossiliferous forma- tions, 723 —— strata, 723 Fothergilla, 504 Four o'clock flower, 561 Fovilla, 232 r 839 Foxglove, 552 Fox-grapes, 462 Fractions in phyllo- taxis, 104. Frames for plants, 798 Francoacez, 503 Frankeniacez, 443 Frankincense, 475, 599 — Pine, 509 Frasera, 540 Fraxinella, 4468 Fraxinus, 533 Free central placenta, drying 243 ; French berries, 472 Freycinetia, 624 Freziera, 453 Friar’s-balsam, 529 Fringes of Passion- flower, 209 Fritillary, 614 Frog-bit, 601 Frogsmouth, or Snap- dragon, dehiscence of fruit of, 308 Frond, 637 Fruit, 298 —— apocarpous, 309 — chemical compo- sition of, 321, 322 — classification of, 319 —— contents of, 321 —— dehiscent, 303 —— dialycarpous, 309 — effect of grafting on, 283 —— indehiscent, 303 — monogynecial, 309, —— multiple or an- thocarpous, 309 — parts which form it, 293 — period required for ripening, 322 — polygynecial, 309 — seedless, 319 — simple, 309 — indehiscent syn- carpous, 313 — tabular arrange- ment of, 318 — winged, 311 Fruiting, 320, 359 Frustule, 267 Frutex, 46 Fruticose, 46 Fruticulus, 46 + Fucacez, 653 —— reproduction in, 273 ; Fuchsia, 493 Fuegia, flora of, 688 Fuirena, 628 Fullers’ Teazel, 515 Fumariacee, 434 Fumitory, 434 —— fertilisation in, 290 Funaria, 643 840 Fungi, 647 — alternation generation'in, 399 —— colour of, 390 — entophytic, 400 — germination of, of 357 y auver — luminosity in, 38, — parasitic, 141 — on fruits, 400 — fossil, 754 reproduction in, 26: resting spores of, 402 Fungoid disease, pre- vention of, 4or Fungus melitensis, 577 Funiculus, 252, 256 Funnel- shaped, 198, 205 Furcate venation, 84, 5 Fusiform, 16, 40 Gap, 508 Gahnia, 628 Gairdner’s _ portable microscope, 764 Galacez, 503 Galactodendron, 587 Galangal-root, 606 Galanthus, 611 Galbanum, 507 Galbulus, 317 Gale, 592 Galeate, 197 Galiez, 512 Galipea, 468 Galls, 403 Gama-grass, 631 Gamassia, 615 Gambeer, 514 Gamboge, 456 Gamogastrous, 239 Gamopetalous, 205,206 Gamophyllous bracts, 190 Gamosepalous, 196 Gangrene, 399 Garcinia, 456 Gardenia, 512 Garlic, 615 Garryacez, 510 Gases, effect on plants, 159 Gasteromycetes, 648 Gasterothalamez, 646 Gattine, 651 Gaudichaudia, 458 Gaura, 493 Geaster, 649 Gelidium, 655 Geissolomez, 572 Gemmation, 110 Gemmule, 334 Genera and orders, 410 Geniculate, 217 Gentian, 539 Gentianacez, 539 Genus or kind, 410 INDEX. Geoffroya, 480 Geographical botany, 657 | Geraniacez, 462 —— fruit of, 315 Germanic flora in Bri- tain, 709 Germ-cell, 275, 282 Germen, 235 Germination, 344, 350, 354, 372 — acotyledonous, 335) 357 —— dicotyledonous, 35! —— effect of rays of light on, 346 — monocotyledon- ous, 354 —— requisites for, 345 — time required for, 357 Gesneracez, 541 Geum, 486 Gibbous, 202 Gigartina, 655 Gillia, 542 Gilliesia, 618 Gilliesiaceze, 618 Gills, 648 Ginger, 605 Ginger-grass, 632 Ginko, 600 Ginseng-root, 509 Gipsy-wort, 554 Glabrous, 33 Gladiolus, 608 Glands, 34 —— lenticular, 36 —— nectariferous, 35 —— vesicular, 36 Glandular hairs, 33 — woody tissue, 17 Glans, 311 Glaucium, 433 Glaux, 558 Gleicheniez, 639 Globe-amaranth, 562 Globularia, 555 Globule, 234, 274 Glochidiate hairs, 32 Glomerulus, 187 Glossary, 809 Glossology, 406 Gloxinia, 541 Glucose, 165 Glume, 191, 208 Glumellz, 208 Glumiferz, 687 Glutin, 166 Glycyrrhiza, 479 Gnetacex, 398 Gnetum, 60 Godoya, 470 Godwinia, 686 Goldfussia, 290, 556 Gomphia, 470 : Gomphocarpus, 536 Gompholobium, 481 Gomphrena, 562 Gongyli, 645 Gonidia, 269, 626 Gonolobus, 536 Goodeniacez, 522 Gooseberry, 313, 502 Goosefoot, 562 Gopher-wood, 599 Gorachand, 481 Gordonia, 452 Gossypium, 448 Gortong, 626 Gourd, 314, 496 Gouty-tree, 449 Grafting, 323 — effects of, 323, 325 —— Knight’s theory of, 325 Grains of Paradise, 606 Graminez, 628 Granules of chloro- phyll in cells, 15x —— of latex, 145 —— of pollen, 231 Grape, 313, 461 —— sugar, 165 Grasses, fertilisation of, 656 — flowers of, 208 —— seed of, 341 Grass-trees, 615 —— of Parnassus, 455 Gratiola, 552 Greek Valerian, 542 Greenheart-tree, 568 Greenland, fossil plants of, 758 Green Laver, 655 —— snow, 655 Greffe des charlatans, 323 Grenadilla, 498 Grevillea, 570 Grewia, 451 Grossulariacee, so2 Ground-nut, 480 Gruby’s portable com- ; Pound microscope, 7 Guaiacum, 466 Gualtheria, 527 Guano, 137 Guarana, 459 Guatteria, 429 Guava, 492 Gueldres Rose, 511 Guernsey-Lily, 612 Guettarda, 512 Guilandina, 481 Guimauve, 447 Guinea-corn, 630 Guinea-hen-weed, 563 Gulf-weed, 655, 700 Gum-Arabic, 163, 482 Gum-Dragon, 480 Gun, effect of alkalies on, 164 Gum-lac, 582 Gum-tree, 491 Gunnera, 493 Gunyang, 548 Gutta-percha, 170, 531 Guttiferz, 456 Gymnema, 536 Gymnocarpous, 645 Gymnosperme, 596 Gymnospermous, 252, 326 flowering plants, fertilisation in, 291 Gymnosperms, fossil, 745 Gymnosporee, 644 Gymnostomum, 643 Gynandrous, 213, 220 Gynerium, 631 Gynizus, 238, 250 Gynobase, 247 Gynocardia, 440 Gyneecium, 212, 235 Gynophore, 240 Gynostegium, 534 Gynostemium, 220 Gypsum as a manure, 139, Gyration, 151 Gyrinopsis, 572 Gyrocarpez, 489 Gyrogonites, 752, 754 Gyrophora, 647 HasBroTHAMNUS, 548 Heemanthus, 611 Hematoxylon, 478, 481 Hemodoracez, 610 Hemodorum, 610 Hagenia, 486 Haidingera, 747 Hairs, 30 —— calycine, 199 —_ circulation of fluids in, 37 — oollecting, 33, 247 — corolline, 34, zor —— form of, 30 — glandular, 33 — in Aristolochia, 287 —— irritable and irri- tant, 33 — on calyx, 197 — on filament, 217 on style, 237, 247, 290 radical, 34 —— ramentaceons, 32 — stellate, 31 Hakea, 570 Halesia, 529 Half-equitant, 112 Half-inferior, 246 Half-superior, 246 Halimocnemis, 563 Halonia, 734 Halophytes, 563 Halorageacez, 493 Haloragis, 493 - Hamamelidacez, 504 Hamelia, 512 Hand-plant, 449 Hepes 506 Hare-bell, 524 Hare’s-foot fern, 640 Hartnack’s' —micro- scope, 767 * — student’s micro- scope, i Haschisch, 585 Hastate, 89, 203 Haulm, 44 Hawthorn, 314 Hazel, fruit of, 311 — nut, 595 Heart’s-ease, 441 Heart-wood, 55 Heat during flowering, 259, 288 Heather, 527 Heaths, 526 Hedera, 509 Hedge-hyssop, 552 Hedyotis, 512 Hedysarum, 478, 481 Heer on Polar fossil plants, 756 Heimia, 487 Hekistotherms, 664 Heliamphora, 433 Helianthemum, 439 Helianthus, 521 Helicoid, 185 Helictereze, 448 Helicteres, capsule of, 35 Heliotrope, 546 Heliotropiez, 546 Hellebore, fruit 312 Helleborez, 427 Helosis, 577 Helvella, 649 Helwingia, 509 ‘Hemerocallidez, 614 Hemicarps, 311 Hemlock, 508 Zee aa 599 emp, 584 Hen and Chickens Daisy, r9z Henbane, 549 — dehiscence of fruit of, 307 pyxidium of, of, 315 Henna, 487 Hepatice, 643. : — reproduction in, 274 Heracleum, 506 Herbaceous, 50, 197 Herbarium cases, 802 formation of, 795 — paper, 801 Herbs defined, 46 Hermannia, 450 Hermaphrodite, 212 Hermodactyle, 616 Hernandiezx, 572 Hesperidium, 314 Heterocephalous, 518 Heterochromous, 517 Heterodromous, 106 Hetercecium, 402 Heterogenesis, 15 Heteromorphic, 285 INDEX. Heterorhizal, 43, 357 Heterosciadez, 506 Heterosporous, 635 Heterotropal, 256 Heuchera, 504 Hevea, 582 Hexagonienchyma, 3 Hexandrous, 216 Hiang-Kwan, 650 Hiatus, 206 Hibbertia, 428 Hibernacula, 110 Hibisceze, 447 Hibiscus, 448 Hickory, 596 Hidden-veined, 83 Hieracium, 520 Hightea, 751 Hilum, 253, 329° Himalayan flora, 683, 696 Hinged dehiscence, 226 Hippocratez, 471 Hippomane, 581 Hippophaé, 571 Hippuris, 493 Hiptage, 458 Hirzea, 458 —— fruit of, 312 Hirneola, 650 Hirsute, 33 Hirtus, 33 Hispid, 33 Histogenetic cules, 13 Histology, 76z Hog-plum, 474 Holland’s triplet, 763 Holly, 530 Hollyhock, 447 Holoptelea, 585 Homaliacez, 573 Homochromous, 517 Homodromous, 106 Homologues of ten- drils, 120 Homomorphic, 285 Homotropal, 342 Honeysuckle, 51x Honkeneja, 445 Hook-climbers, 386 Hooked hairs, 32 mole- Hooker on insular floras, 673 Hooker's ___ classifica- tion, 423 Hop, 585 —— fruit of, 317 Hordeum, 630 Horehound, 554 Hornbeam, 595 Hornwort, 588 Horny albumen, 333 Horse-chestnut, 459 Horse-radish, 437 Horse-radish tree, 483 Horsetails, 281, 636 Hottentot’s Fig, 510 Houseleek, 499 Houttuynia, 590 Hoya, 536 Hudsonia, 439 Hugonia, 465 Humboldt’s floral Re- gion, 686 Humiriacez, 460 Humulus, 585 Humus, 126, 134 —— coal of, 134 Hungarian balsam, 599 Hura, 581 Husk, 312 ~ Huyghenian eye-piece or ocular, 765 Hya-hya, 537 Hyacinthus, 616 Hybridisation, 297 Hybrids, 297, 409 —— nomenclature of, 409 Hydnocarpus, 440 Hydnora, 577 Hydnum, 649 Hydrangee, 503 Hydrastis, 428 Hydrocera, 464 Hydrocharidacez, 601 Hydrocharis, 602 Hydrochloric acid gas, effect on plants, “160 Hydrocotyle, 506 Hydrocyanic acid, 170 Hydrodictyon, 655 Hydrogen in plants, 126 Hydrogeton, 626 ae, 542 ydropeltis, 432 Hydrophyllaceze, 542 Hydrophyta, 652 Hygrophorus, 650 Hymenza, 481 Hymenium, 647 Hymenomycetes, 648 Hymenophyllez, 639 Hymenophyllites, 745 Hymenothalamez, 645 Hyoscyamus, 549 Hypanthodium, 181 Hypecoum, 434 Hypericaceze, 458 Hypha, 269, 646 Hyphene, 622 Hyphomycetes, 649 Hypnum, 643 Hypocarpogean, 344 Hypochilium, 602 Hypocotyledonary, 41 Hypocrateriform, 205 Hypogeal, 356 Hypogynous, 212 Hypoxidacee, 612 Hypoxis, 612 Hypsometrical tempe- raturés, 661 Hyptis, 555 Hyssop, 554 — of Scripture, 438 Hyssopus, 554 Hysterophyta, 647 Icacina, 453 Iceland Moss, 646 Ice plant, 500 Idiothalamez, 646 841 Ignatia, 538 lex, 530 llicineze, 529 Illecebreze, 459 Illicium, 429 —— capsule of, 315 Imbibition, 124 Imbricated, 110, 194 Impatiens, 464 Impari-pinnate, 93 Impregnation, 291 Inarching, 324 Included, 227 Incumbent, ‘340 Indefinite inflores- cence, 174, 181 — stamens, 216 —— vascular bundles, 53 Indehiscent fruits, 303, 309, 313 Indeterminate, 174 India-rubber, 582 Indian Archipelago, flora of, 684 —— arrow-root, 606 —— corn, 630 —— cress, 465 — cress, fruit of, 311 — fig, 500 — flora, 683 — hemp, 585 —— shot, 607 —— tobacco, 525 Indigo, 171, 480 Indigofera, 480 Induplicate, 112, 193 Indusium, 632 Inenchyma, 6 Inferior applied to ovary and flower, 195, 246 Inflated, 198, 200 Inflorescence, 17, 172 — compound defi- nite, 186 — compound inde- finite, 181 — determinate, defi- nite, or terminal,175, 182 — diagrams to illus- trate types of, 187 — indefinite or axil- lary, indeterminate, 174, 176° —— mixed, 186 — tabular view of, 18 Infundibuliform, 205 Innate, 224 Inocarpus, 572 Inorganic compounds, r24 — constituents of plants, 128 — matters, iron ab- sorbed, 132 ——- tabular view of, 129 Insectivorous plants, 382 842 Insects, diseases of plants caused by, 403 —— fertilisation by, 284 — in Darlingtonia and Nepenthes, 384 —— in fertilisation of orchids, 286 —— in pitchers, 384 —— pollen carried by, 28, Insular floras, 673 Integer, 86 Integument, general, 25 Integuments, 326 — ovular, 253 Interbreeding, pre- vention of close, 286 Intercellular spaces, 7 — passages or canals, 7 Interfoliar, 98 Internal membrane of seed, 327 — or intrarius em- bryo, 340 Internodes, 45, tor Interpetiolary, 98 Interruptedly pinnate, 93... Intextine, 230 Intine, 230 Intrarius, 340 Introrse, 226 Inula, 520 Inulin, 163 Inverted, 257, 341 Involucel, 190 Involucre, 190 Involute, rr Todine, 10, 132 Tonidium, 441 Ipecacuan, 513 —— glands of, 35 Tpomeea, 544 Treland, flora of, 705 Iridacez, 608 Tridzea, 655 Iris, 609 Irish Moss, 655 Iron in plants, 132 Tronwood, 528 Irregular monopeta- lous or gamopeta- lous corollas, 206 ——polypetalous corol- las, 205 —— stamens, 283 Irritability, 374, 383 —— of Dionza and Drosera, 380 -—— of twining plants and tendrils, 385 Irritable hairs, 33 Irritant hairs, 33 Isatis, 437 Isertia, 512 Isocheimal lines, 659 Isoetaceze, 640 Isoetes, reproduction of, 278 INDEX. Isle of Sheppey, fossil plants of, 751 Ispaghil, 566 Isomeric, 166 Isonandra, 531 Isosporous, 635 Isostemonous, 215 Isotheral lines, 659 Itea, 504 Ivory Palm, 622 Ivory, vegetable, 333 Ivy, 509 Ixia, 608 JABORANDI, 59x Jack fruit, 316 Jacob’s ladder, +542 Jacquinia, 531 ae 621 alap, 544 Jamaica pepper, 492 Janipha, 582 Japan Lacquer, 474 Japanese flora, 682 Jars for holding pre- parations, 803 Jasminacee, 537 Jasmine, 532 Jateorhiza, 430 Jatropha, 582 Java, upper Region of, 68. 4 Jerusalem artichoke, 52r Jessamine, 532 Jew’s Ear, 650 Jew’s-mallow, 450 Job’s-tears, 632 Jonquille, 112 Juglandacez, 595 Juglans, 596 Jujube, 473 Juncacee, 619 Juncaginez, 623 Juncus, 619 Jungermanniez, 643 — reproduction of, 274 jigeee fruit of, 317 uniperus, 599 Jussiza, 493 7 Jussieu’s classification, 41 Justicia, 556 Jute, 450 Kmprer’s floral Re- gion, 682 Kalmia, 527 — fertilisation of, 283 Kamalo, 582 Kandelia, 488 Kaneh, 632 Kaneh-bosem, 632 Kangaroo apple, 548 —— grass, 631 Karcom, 609 Kat, 471 Kava, 591 Kawrie-pine, 599 Keel, 205 Keg-fig, 528 Kelp, 655 Kerguelen Island cab- bage, 437 Kernel, 326 Kiddah, 568 Kidney bean, fertilisa- tion in, 288 Kie-kie, 624 Kigelia, 54 Kind or genus, 410 Kinic acid, 170 Kinnabaris, 622 Kino, 480 Kirschenwasser, 486 Kishuim, 495 - Kleistogamous, 656 Knots, 116 Knotwort, 498 Kochia, 563 Kokerboon, 615 Kola, 449 Kombe poison, 537 Koochla, 538 Koosht, 520 Kousso, 486 Krameria, 442 Kumquat, 455 Kussemeth, 630 Kwei-hwa, 533 LaBeLiuM or lip, 205 Labia, 206 Labiate, 552 fertilisation in, 289 fruit of, 311 —— Region of, 680 Labiate, 198, 206 Labiatiflore, 519 Laburnunm, 479 Lace-bark, 572 Lace-plant, 626 Laciniz, 7, 198 Laciniated, 87, 201 Lacis, 588 Lacistema, 590 Lacistemacez, 589 Lacquer, 474 Lactuca, 522 Lactucarium, 522 Lacunz, 13 Ladanum, 439 Lagenaria, 496 Lagerstrémia, 487 Lagetta, 572 Lamb’s Lettuce, 515 Lamelle, 249, 648 Lamiacez, 551 Lamina, 201 —— of leaf, 82 Laminaria, 654 —zone of, in Britain, 716 Lamium, 554 Lanceolate, 89 Lancewood, 430 Langsat, 460 Lansium, 460 Lantana, 556 Laportea, 584 Larch, 599 Larch, cone of,’ 317 Lardizabala, 431 Larix, 599 Larkspur, 427 Lasiandra, 489 Lasiopetalum, 450 Lastrea, 639 Latent, 112, 117 Lateral, 108, 247, 340 — applied to the parts of a flower, 195 dehiscence, 226 Latex, 21, 745. —— granules in, 145 Lathreea, 551 $ Lathyrus, 482 Laticiferous vessels, 21, 145 —— — movements in, 145 Latiseptz, 436 Latitudinal range of vegetation, 678 Lattice-plant, 686 Lauracez, 566 — fossil, 754 —— Region of, 699 Laurelia, 589 Laurus, 567 Laurustinus, 51z Lavender, 554 Laver, 655 Lavoisiera, 489 Lawsonia, 487 Layering, 113 Leaf, 79 —— arrangement, ror —— climbers, 386 —— the type of all parts of the flower, 172 Leaf-buds, 108, 335 —— aerial, 114 —— anomalies of, 116 — axillary, 108 —— extra-axillary,117 —— lateral, 108, 112 — subterranean, 114 transformations of, 116 : Leafless acacias, 96 Leaflets, 86, 91 Leaf-stalk, 94 Leafy bracts, 189 Leather-wood, 572 Leaves of acotyledons, IOI —— aerial, 79 —— analogy of car- pels to, 235 —— anomalous forms of, 99 i —— arrangement in the bud, rz — arrangement on the axis, roz —— buds on, 118, 358 —— calycine, 195 —— cauline, ror — clustered or fas- cicled, 369 Leaves, colouring’mat- ter of, 392 — compound, 85, 86, gz — deciduous, 83, 123 —— diseases of, caused by insects, 40: — effect of Lgcitop chloric and sulphur- ous acid gas on, 160 —— effect on the at- mosphere, raz, 157 —— evergreen, 83, 123 exhalation of, 121 fall of, 123 ——- floral, ror, 189 forms of, 85 — functions of; raz — general summ: of conformation of, 93 of dicotyledons, I00 — of monocotyle- dons, tox — primordial, 335 , —— propagation 118 ror, by, radical, ror —— ramal, ror —— seminal, roz, 339 —— simple, 85, 86 —— skeleton, 79 spiral, gt — spiral arrange- ment of, 103 — structure of, 79 — submerged, 79, 82 — succulent, go transpiration of, I2z r vascular system of, 79 —— venation of, 83 Lebonah, 475 Lecanora, 647 Lecca-gum, 533 Lechea, 439 Lecidea, 646 Lecotropal, 255 Lecythidez, 491 Lecythis, 492 Ledum, 527 Leea, 461 Leek, 615 -Legume, ous, 312 or pod, 312 Legumin, vegetable, 166 Jomentace- Leguminosz, 476 — fertilisation in, 289 fossil, 754 fruit of, 312 Lemnez, 625 Lemon, 314, 454 Lemon-grass, 631 Lemon-plant, 558 Lenses, 762 — for microscope, 762 INDEX, Lentibulariaceze, 557 Lenticels, 36 Lenticular glands, 36 Lentisk, 474 Leontice, 431 Leopard’s-bane, 521 Leopoldinia, 622 Lepidium, 435 Lepidocaryine, 621 Lepidocaryum, 622 Lepidodendron, 733 Lepidophyllum, 730 Lepidostrobus, 733 Lepidote, 3: Lepis, 3z Lepistemon, 544 Leptanthus, 618 Leptolena, 452 Leptosiphon, 542 Leptospermum, 491 Leschenaultia, 523 Lessonia, 654 Letterwood, 587 Lettuce, 522 Leucodendron, 570 Leucojum, 612 Leucopogon, 528 Leycesteria, 511 Lianas, 45 Lias, flora of, 747 Liber, 57 Libocedrus, 598 Lichenes, 644 Lichenin, or Lichen- starch, 646 Lichens, fertilisation of, 269 — Region of, 679 Lid, 199, 232, 307 Life of plants, dura- tion of the, 359 Light, as affecting plant distribution, 667 — effect of different rays on the colours of plants, 390 —— effect of rays on germination, 346 — effect of rays on plants, 159 — effect on flowers, 258, 263 —— effect on growth of plants, 354 —— effects on respira- tion of plants, 156 —— effect of, on sensi- tive plants, 376 Lign Aloes, 572 Ligneous stem, 50 —— tissue, 16 Lignin, 9, 165 Lignum-vite, 466 Ligulate, 207 Ligule, 99 Ligulifloree, 519 Ligustrum, 534 Lilac, 533 Liliacez, 613 Lilies of the field, 615 Lilium, 615 Lily of the fields, 612 Lily of the valley, 614 im aoe 5 —— of calyx, 1 —— of leaf, 82 ? Lime, 455 Lime in plants, 132 — in soils, 135 — phosphate and sulphate of, as ma- nures, 139 Lime tree, 450 Limnanthacez, 465 Limnanthes, 465 Limnocharis, 624 Limonia, 454 ' Linacee, 463 Linaria 582 Linden-tree, 450 Lindley’s _ classifica- tion, 420 Linear, 88, 203 Linen, 16 Ling, 527 Linnza, 511 Linnzus’ artificial sys- tem, tabular view of classes and orders of, 474 — floral Region, 680 Linnean artificial sys- tem, 413 —— system, tion of, 264 — system, terms of, founda- > 21 Linseed oil, 464 Lip, 198, 205 Liparis, 604 Lipped, 206 Liquidambar, 504 Liquid manures, 140! Liquiritia, 479 Liquorice, 479 Lirelle, 645 Liriodendron, 429 — fruit of, 312 Lissanthe, 528 Listera, 604 —— fertilisation in, 288 Litchi, 459 Lithospermum, 547 Litmus, 627 Littoral zone of Bri- tain, 715 Liverwort, 643 —— reproduction of, 274 Lizard’s tail, 590 Loasacez, 493 Lobed, 87 Lobeliacez, 525 Loblolly Pine, 599 Localities of plants, 668 Loculament, 225, 242 Loculicidal, 304 Locust, 179 Locust-tree, 48z Lodiculz, 208 Lodoicea, 621 Loganiacee, 537 Logwood, 481 843 Lolium, 631 Lombardy Poplar, 592 Lomentacez, 436 Lomentaceous legume, 312 Lomentum, 312 Lonchopteris, 732 London clay, fossils of, 751 Longan, 459 Long purples, 605 Lonicereze, 512 Loosestrife, 487 Loquat, 486 Loranthacez, 574 Loranthus, 575 Lote-bush, 473 Lotus, 478 — bean, 432 —— tree, 458 Love-apple, 549 Love-lies-bleeding, 562 Lucerne, 479 Lucuma, 531 Luffa, 496 Luhea, 450 Luminosity of plants, 389 3 Luminous fungi coal-mines, 389 Lung-wort, 647 Lupinus, 479 Lupulin, 585 Lurp, 497 Luzula, 619 Lychnis, 445 Lychnophora, s2r Lycoperdon, 65 Lycopersicum, 549 Lycopod, 641 Lycopodiaceze, 640 reproduction in in, 27) Lycopodites, 733 Lycopodium, 641 Lycopus, 554 Lygeum, 632 Lyginodendron, 742 Lygodium, 639 Lymphatic, 33 Lyrate, 87 Lythracez, 487 Lythrum, _trimorphic flowers of, 285 Masa, 5 Macadamia, 570 Macahuba-palm, 622 Mace, 328, 569° Mackinlaya, 509 Maclura, 587 ‘Nab, Dr. W. R., on Calamites, 737 Macrochloa, 632 Macrocystis, 654, 701 Macropiper, 59x Macropodous embryo, 33! Macrosporangia, 278 Macrospores, 278, 640, Macrozamia, 600 844 Madder, 514 Madeira, plants of, 681 Madhuca tree, 532 Madia, 521 Mesa, 531 Magalhaensand Tierra del Fuego flora, 688 Magnolia, fruit, 312 Magnoliacez, 428 Magnolias, Region of, 8x 6 Mahogany, 460 —— fruit of, 315 Mahonia, 432 Maiden-hair, 640 Maize, 630 — fruit of, 31 Malachadenia, 605 Male Shield-fern, 639 Malesherbia, 497 Malic acid, 170 Malicorium, 314 Mallotus, 582 Mallow, 446 Malpighiacez, 457 Malvaceze, 446 Mammee apple, 457 Manchineel, 58x Mandragora, 549 Mandrake, 549 Manganese in plants, 132 Mangifera, 473 Mango, 311 Mangold-wurzel, 562 Mangosteen, 457 Mangrove, 7488 Manicaria, 622 Manihot, 582 Manilla hemp, 608 Manioc, 582 Manna, 443, 479, 533) 99 Mannite, 165 —— in seaweeds, 165 Mantellia, 750 Manure, application of. 136 Manures, comparative value of, 137 Manuring with green crops, 140 —with sea-weeds, 140 Manzanita, 527 Maple, 458 —— sugar, 164 Maranta, 607 Marantacez, 606 Maraschino, 486 Marattia, 640 Marattiez, 639 Marcescent, 200, 211 Marcgraavia, pedun- Cular pitchers of, 290 Marceravia, 452 Marchantia, 644 Marchantieze, 643 — reproduction of, 274 INDEX. Mare’s-tail, 493 Margaric acid, 168 Marginate, 198 Margosa, 460 Marine flora of Britain, 714 —— vegetation, zones of, 699 Marjoram, 554 Marking-nut, 474 Marmalade, 531 Marrubium, 554 Marsdenia, 536 Marsh Mallow, 447 — trefoil, 540 Marsilea, 640 Marsileacez, 640 — reproduction of, 279 | Martynia, 541 Marvel of Peru, 560 Mask-like, 207 Mastich, 474 Maté, 530 Matico, 59x Mattulla, 32 Maturation of the peri- carp, 319 —— of the seed, 343 Mauritia, 622 Mayaca, 623 May-apple, 428 Meadow grass, 631 — saffron, 616 Mealy, 333 Mechoacan-root, 544 Meconic acid, 170 Meconopsis, 433 Medicago, 479 Medick, 479 Mediterranean flora, 680 Medlar, 314 —— of Surinam, 531 Medullary rays, 50, 59, 75 —— sheath, 53, 75 Megacarpeea, 435 Megasporangia, 278 Megaspores, 278 Megatherms, 663 Megistotherms, 664 Melaleuca, 491 Melampyrum, 551 Melanosporee, 653 Melanthacez, 616 Melanthium, 616 Melastomacez, 489 —— Region of, 687 Melegueta _ pepper, 606 Meliacezx, 459 Melilotus, 479 Meliosma, 459 Melissa, 554 Melloca, 446 Melocanna, 632 Melon, 314, 495 Memecylon, 489 Meninia, 556 Menispermacez, 430 Mentagraphytes, 651 Mentha, 554 Mentzelia, 494° Menyanthee, 539 Menziesia, 527 Merenchyma, 3 Mericarps, 312 Merismatic division of) cells, 14, 267 Merithalli, 362 Mertensia, 547 Merulius, 650 Mesembryacez, 510 Mesembryanthema, Region of, 689 Mesembryanthemum, 500 Mesocarp, 300 Mesochillium, 642 Mesophlceum, 57 Mesophyllum, 80 Mesosperm, 327 Mesotherms, 664 Mesua, 457 Metamorphic rocks, 723 Metamorphoses, vege- table, 362 Metasperms, 292 Meteoric flowers, 263 Meteorological influ- ence on odours of plants, 396 Metroxylon, 621 Mexico and Guiana, flora of, 686 Mexico, flora of Highlands of, 686 Meyen’s phyto-geo- graphical zones, 692 — zones, tabular view of, 694 Mezereon, 572 Michaux’s floral re- gion, 681 Miconia, 489 Microcachrys, 597 Microgonidium, 270 Micrometer, 771 Micropyle, 329, 254 Microscope, 761, 763 — compound, 765 — focal adjustment of, 779 —— its uses, 761 —— mode of using it, —— simple, 763 — works on the, 793 Microscopic apparatus, TTA: i ‘ — manipulation, 772 —— objects for exa- mination, 780 — objects, preserva- tion of, 783 — observations, sources of error in, —— re-agents, 773 —— test objects, 772 Microscopical demon- strations, objects and illustrative tissues, 78r Microscopical slides, — specimens in a case, 792 — turn-table, 786 Microsporangia, 278 Microspores, 278, 640 Microtherm, 664 Miersia, 618 Mignonette, 438 Mikania, 521 Mildew, 399 Milk-tree, 537 Milk-vessels, 2z Milk-wort, 44 Millet, 63x Mimosa, 482 Mimosites, 751, 755 Mimulus, 552 Mimusops, 531 Miners, 403 Mint, 554 Miocene. Arctic fossil flora, 755 —— flora, 754 —— flora of Europe, 756 Miostemonous, 215 Mirabilis, 561 Mistleto, 142, 57: Mixed inflorescence, 186 Mock-apple, 496 —— orange, 490 Modecca, 497 Moisture, effect - of, in distribution of plants, 662 — in germination, Mallugo, 500 Momordica, 494 Monadelphous, 218 Monandrous, 216 Monembryony, 330 Monetia, 534 Moniliform, 217 — root, 40 — vessels, 20 Monimia, 589 Monimiacez, 588 Monkey-bread, 449 Monkey-pot, 307, 315, 492 . Monkey’s dinner-bell, 8: 58x Monkshood, 427 Monk’s-rhubarb, 565 Monocarpic, 359 Monochlamydee, 566 Monochlamydeous, 192 Monoclinous, 367 Monocotyledones, 6or Monocotyledonous, 334 — embryo, 336, 362 Monocotyledons, leaves of, ror —phyllotaxis of, ror Monocotyledons, root of, 42 Moneecious or monoi- cous, 212, 273, 567 — plants, fertilisa- tion in, 284 : Monogamia, 415 Monogyneecial, 309 Monopetalous, 203 Monophyllous, 196 Monosepalous, 196 Monospermous, 309 Monothecal, 222 Monotropez, 526 Montpellier Scam- mony, 536 Monstera, 685 Monstrosities of calyx, 196 of flowers, 172 Montia, 446 Montinia, 493 Moon-plant, 545 seed, 430 Moracez, 586 Mora wood, 481 Morchella, 649 Morel, 649 Morina, 515 Morinda, 514 Moringacee, 482 Morphia, 433 Morphology, 362 Morus, 586 Mosses, 641 leafy, 276 — morphology of, 643 : —— preparation of, 800 7 —— reproduction in, 2 Mountain Tobacco, 52x Mountains of Europe, flora of, 679 Mouriria, 489 Movements in cells, I51 in flowers, 386 in plants, 375 —— in plants, causes of, 378 Moving cells of vau- cheria, 269 —— spores, 265 Moxa, 521 Mucor, 649 Mucronate, 89 Mucuna, 480 Mucus, definite, 26 Mudar, 536 Mueller on fertilisation of grains, 656 Mulberry, 316, 586 Mull, Miocene flora of, 755 Moullein, 552 Multicostate, 84, 93 Multifid, 87, 248 Multijugate, 93 Multilocular, 241, 299 Multipartite, 248 INDEX. Multiple, 309° ——or Polygyncecial Fruits, 316 Multiplication of parts of flower, 365, 370 Mummy-cloth, 16 Mummy-wheat, 630 Munjeet, 514 Munsteria, 752 Muriform cellular tis- sue, 4, Musa, 608 Musacez, 607 Muscee volitantes, 777 Muscardine, 650 Musci, 641 — Region of, 679 Muscovado Sugar, 164 Mushroom, 649 —— family, 647 Musszenda, 514 Mustard, 437 — tree, 534 Mycelium, 357 Mycoderma, 650 Mylitta, 650 Myoporinez, 555 Myoporum, 555 Myosotis, 547 Myrica, s92 Myricacee, 592 Myricariz, 443 Myriophyllum, 493 Myristica, 569 Myristicacez, 569 Myrobalans, 489 Myrosin, 169 Myrospermum, 480 Myroxylon, 480 Myrrh, 475 Myrsinacez,. 531 Myrtacez, 490 —— Region of, 699 Myzodendron, 574 NABEE, 427 Nachet’s achromatic microscope, 769 Nadelholzer, 88 Naiadacez, 686 Naias, 686 Naked, 252 Nannari, 536 Napiform, 40 Narcissus, 611 Nardoo-plant, 640 Nardostachys, 515 Narthecium, 616 Narthex, 507 Nascent, 211 Naseberry, 531 Nasturtium of gar- dens, 465 Natural grafting, 324 —— selection, 407 —— system, 406, 415 Navicular, 202 Nectandra, 568 Nectaries, 209, 234, 369 —— in Orchids, 288 Nectariferous glands, 35 Nectarine, 485 Needle trees, 88 Nelsoniez, 556 Nelumbium, 432 Nelumbonez, 432 Nemophila, 542 Neottia, 604 Nepenthacez, 578 Nepenthes, 578 —— insects in pitchers of, 384 Nephelium, 459 Nerd, or Nard, 515 Nerium, 537 Neroli oil, 454 Nertera, 512 Nervation, 83 Netted veins, 84 Nettle, 584 —— fertilisation of, 283 —— tree, 585 Neurada, 485 Neuropteris, 732 Neuter, 368 New Zealand Flax, 615 — flora of, 691 —— spinach, soo Nicker tree, 481 Nicotina, 550 Nicotiana, 550 Nidularia, 649 Nigella, 427 Night-flowering plants, 262 —— Cereus, soz Nightshade, 548 Nilssonia, 749 Nincopipe, 559 Nipa, 624 Nipadites, 751 Nisa, 574 Nitella, 652 Nitraria, 458 Nitrogen in plants, 12 Nodes, 45, ror Nodules, woody, 116 Nodulose, Néggerathia, 741, 745 Nolana, 547 Nomenclature of classes, 411 Norfolk Island pine, SOB sss North Asiatic flora, 680 North European flora, 68 jo Northern part of North America, flora of, 681 Norway spruce, 599 Nosology, 397 Nostoc, 646, 654 Nostochinez, 654 Notorhizez, 340, 435 Nourishment of plants, 124 Noyau, 486 Nuclei, 25: | Nucleoli, 25x Nucleus of a cell, 9 845 Nucleus or kernel, 253, 326 Nuculanium, 315 Nucule, 251, 274 Nucumentacez, 436 Number of species of plants, 658 Nuphar, 432 Nut or glans, 311 Nutmeg, 311, 328, 569 Nutrition, requisites for, 125 Nutritive organs, func- tions of, 124 —— products of dif- ferent crops, 167 ux vomica, 538 Nyctaginacez, 560 Nyctanthes, 532 Nymphwzacez, 431 Nymphza alba, seed of, 326 Nyssa, 510 Oak apples, 403 — lungs, 647 —— spangles, 404 Oaks and Firs, Region of, 680 Oats, 630 Obcordate, 89, 202 Object-glass of mic- roscope, 765 Objectives of Ross and Gundlach, 794 Oblique, 86, 202 Oblong, 89 Obovate, 89 Obsolete, 198 Obvolute, 112 Oceanic Region, 684 Ochnacez, 469 Ochrea, 97 Ochro, 448 Ocotea, 568 Octandrous, 216 Octangular, 46 Ocymum, 554 Odours in natural or- ders, 396, 397 | — of flowers in fer- tilisation, 284, 288 dogonium, repro- duction of, 270 GEnanthe, 508 Enothera, 493 Offset, 113 Oidium, 650 Oil in seeds, 168 —— in fruits, 321 —— in vegetables, 167 Oils in cells, 12 Oily albumen, 333 Olacaceze, 453 Olax, 453 Oldenlandia, 514 Oldfieldia, 532 Old-man’s-beard, 613 , Oleacez, 532 Oleander, 537 Oleaster, 570 Oleic acid, 168 846 Olibanum, 475 Oligaudidus 2x6 Oligospermous, 312 Olive, 533 Omam, 508 Omphalea, 583 Omphalobium, 476 Omphalode, 329 Onagracee, 492 Oncidium, 604 Oncobez, 440 Onion, 615 Onobrychis, 479 Onygena, 649 Oogones, 272 Oogonia, 268 Oolitic flora, 748 Oophoridia, 278 Oosporangia, 272 Oospore, 268 Opening of flowers, 262 Operculate, 199, 232, 307 : Operculum, 307 Ophelia, 540 Ophiocaryon, 459 Ophioglossacez, production of, 28 Ophioglossez, 639 Ophiopogonez, 614 Ophrys, 604 Opilia, 453 Opium Poppy, 433 Opoponax, 507 Opposite, 102, 112 Opuntia, 502 Orach, 562 Orange, 314, 454 Orbicular, 87 Orchid flower, section of (Darwin), 373 Orchids, fertilisation of, by insects, 288 — nectaries in, 288 Orchil, 647 Orchidacez, 602 — dehiscence of fruit of, 306 fertilisation of, re- 2 Orchideous, 205 Order or family, 410 Orders in northern hemisphere, 678 — in southern hemi- sphere, 678 —— restricted in dis- tribution, 677 Orebim, 592 Oregon flora, 682 Oreodaphne, 569 Organic acids, 127 — bases, 170 — compounds, 124 —— constituents of plants, 125 Organ-nut, 429 Organogeny, 243 Organography, 718 Organs, compound, 25 —— elementary, x INDEX. Organs of nutrition or vegetation, 25 — of reproduction, 25, 171 — of reproduction, functions of, 264 — subordination in, value of, 416 Ee suppression of, 5 —— symmetry of, 363 Oriental Plane, 594 Origanum, 554 Ornus, 533 Orobanchacee, 550 Orris-root, 609 Orthoplocez, 340, 435 Orthotrichum, 643 Orthotropal, 255, 330 Orthotropous, 255 Orthosperme, 506 Oryza, 630 Osbeckia, 489 Oscillatoria, 654 Osmose, 143 Osmundez, 639 Osyris, 574 Otozamites, 749 Ourari poison, 538 Ouvirandra, 626 Ovary, divisions 240 —— or germen, 235 — position of, 246 Ovenchyma, 4 vule, 235, 252 —— coverings of, 253 —— dehiscence of, 252 in, —number in the ovary, 257 — position in the ovary, 256 Ovules of gymno- sperms, 292 Oxalic acid, 170 Oxalidaceee, 464 Oxalis, movements in leaves of, 377 Oxlip, 558 Oxycoccus, 526 Oxygen in plants, 126 — absorbed by flowers, 258 —— effect on colours, 393, a —m_ germination, 345 Oyster-plant of Ame- rica, 522 PacirFic IsLanps, flora of, 684 Padina, 654 Pederia, 512 Pzonia, 427 Paiophyll, 392 Pakyoth, 496 Palzontological tany, 718 Palate, 207 Palea, 208 Palez of artichoke, 190 bo- Palissya, 748 Paliurus, 473 Palma Christi, 58 Palmacites, 752 Palme, 619 Palmate, 87 Palmatifid, 87 Palmellaceze, 654 Palmite, 619 Palm, dichotomous stem of, 69 — oil, 621 Palms of chalk, 752 — phyllotaxis 108 —— Region of, 687 — stem, formation of, 66 Palo de Vaca, 587 Palo de Velas, 541 Pampas-grass, 631 Panama hats, 624 Panax, 509 Pancratium, 612 Pandanacez, 624 Pandanocarpum,, 751 Pandanus, 624 e Panduriform, 87 Pangium, 440 Panicle, 177, 208 Panicum, 631 ~ Panspermism, 15 Pansy, 441 Papaveracez, 433 Papaw, 314 — tree, 497 Papayacesz, 496 Papayrolez, 440 Paper mulberry, 587 —— for drying plants, of, 97 reeds, 628 Papilionaceous corolla, 205 Papillz of roots, 38 —— of epidermis, 30 Pappus, 199 Papyrus, 628 Para rubber, 582 Paracorolla, 210 Paraguay Tea, 530 Paraphyses, 210 Parasites, 40, 141 Parasitic fungi, 141 Parastemones, 210 Pareira-brava, 430 Parenchyma, 37, 80 Pariglin, 617 Paris, 618 Paritium, 448 Paridez, 618 Parietal placenta, 242 Parietaria, 584 — fertilisation of, 283 Parietin, 647 Pari-pinnate, 93 Parkia, 478 Parmelia, 647 Parmentiera, 541 Parnassia, 455 Parnassia, fertilisation of, 283, 286 Paronychiacez, 498 Paropsia, 497 Parsley, 507 Parsnip, 507 Parthenogenesis, 265 Partite, 86 Partitions, 86 Passifloraceze, 497 Passion-flower, 498 Pastilles, 529 Pastinaca, 507 Patchouly, 554 Patella, 645 Patulous, 197 Paullinia, 459 Pavia, 459 Peach, 311, 485 Pear, 314, 486 Peas, 477 Pecopteris, 731 Pectic and pectosic acid, 164, 321 Pectinate, 87 Pectinated stomata, 637 Pedaliez, 540 Pedate, 87 Pedatifid, 87 Pedicel, 172 Pedicellate, 172 Peduncle, 172 — fleshy, 310 —— hollow, 174 Pedunculate, 172 Peg-grafting, 325 Pelargonium, 462 Pellitory, 584 —— of Spain, 520 Peloria, 552 Pelorisation, 372 Peltate, 87, 250, 257 Peltate hairs, 33 Penzacez, 571 Pencil-cedar, 599 Penicillium, 650 Penny-royal, 554 Pentadesma, 456 Pentagonal, 363 Pentamerous, 363 Pentandrous, 216 Pentapetalous, 203 Pentaphyllous, 197 Pentasepalous, 197 Penthorum, 500 Pentstemon, 551 Pepo or Peponida, 314 Pepper, 591 Pepper, Jamaica, 492 Pepper-brand, 399 Peppercorn, 403 Peppermint, 554 Pepperwort, 640 Perenchyma, 10 Perennial, 355 Pereskia, 50x Perfoliate, 100 Perianth, 193 Pericarp, 298, 300 —— maturation of the, ot) g é Pericarpial coverings, 326 Pericheetial, 641 Pericladium, 97 Periderm, 58 Perigone, 193 Perigynium, 209 Perigynous, 213, 246 Periodical phenomena in plants, 263 Perisperm or albumen, 254, 327, 332 Perispermic, 343 Peripherical, 342 Periploca, 536, Penspore, 335 Peristomatic, 28 Peristome, 641 Perithecia, 268 Peritropous, 257 Periwinkle, 537 Permian fossils, 744 * Pernambuco-wood, 482 Persea, 569 Persian flora, 685 Persimon, 528 Persistent, 211, 248 Personate, 207 Persoonia, 570 Pertuse, 8 Perulz, 109 Peruvian cherry, 549 Petaline hairs, 201 Petaloidez, 601 Petals, 200 — anomalies in, 209 Petiolary, 98, 120 Petiolate, 339 Petiole, 82, 94 Petioles, | anomalous forms of, 99 Petiolules, 92 Petiveriez, 563 Petroselinum, 507 Pettigrew’s views on circulation in plants, 147 Peumos, 589 Peuce, 748 Peziza, 649 Phacelia, 542 Phzosporeze, 653 Phalaris, 631 Phallus, 650 Phanerogamous, 171 — plants, 425 s — plants essential organs of, 264 — plants, fertilisa- tion in, 28 Pharbitis, 545 Phascum, 643 Phaseolex, 478 Phaseolites, 754 Phaseolus, 481 Philadelphacezs, 489 Philesia, 617 Philippodendron, 450 Philydrum, 619 Phillyrea, 533 Phleum, 631 Phlorizin, 166 Phlox, 542 Pheenicites, 754 INDEX. Pheenix, 621 Phoranthium, 173 Phormium, 615 Phosphorescent Tics, 389 Phragmata, 244 Phycochrome, 646 Phylica, 472 Phylla, 195 Phyllanthus, 580 Phyllaries, 190 Phyllocladus, 597 Phyllodium, 96 Phyllogen, 67 Phylloid, 173 Phyllolobez, 476 Phyllophor, 67 Phyllotaxis, rox — fractions in, 104 — of acotyledons, 107 —— of bracts, 189 — of dicotyledons, 107 — of monocotyle- dons, 107 — of palms, 108 — of pines, 108 Physalis, 549 Physic-nut, 582 Physiognomic plants, aga- 75 Physomyces, 649 Physomycetes, 649 Physostigma, 481 Phytelephas, 622 Phytochlor, 258 Phyto-geographic Re- gions, 678 . Phytolaccaceze, 563 Phytons, 109, 362 Phytozoa, 265 Phytozoids, 234 Piassaba, 622 Picea, 599 Picotees, 445 Picrzena, 469 Picrotoxin, 430 Pietra fungaia, 650 Pig-nut, 507 Pigs’-faces, soo Pileorhiza, 38 Pileus, 647 Pili, 30 Pilocarpus, 467 Pilose, 33, 199 Pilularia, 640 Pimenta, or Pimento, A Pimpinella, 508 . Pinakenchyma,. 4 Pinaster, 599 Pinckneya, 513 Pine-apple, 316, 613 Pines, phyllotaxis of, 108 Pin-eyed, 212 Piney resin, 451 Piney tallow, 451 Pinguicula, 383, 557 Pinites, 739, 754, 757 —— succinifera, 754 Pink, 445 Pink-root, 539 Pinnate, 92 - Pinnatifid, 86, 201 Pinnatipartite, 87 Pinus, 599 Pinus fossil, 755 Piper, 59 Piperacez, 590 —— Region of, 686 Piratinera, 587 Piscidia, 482 Pisonia, 561 Pissadendron, 739 Pistacia or Pistachio- “ nuts, 473 Pisteze, 685 Pistil, rg1, 211, 234 —— mature, 298 Pistillary cords, 240, 252 Pistillate, 368 Pistillidium, 250, 265 Pistilliferous, 212, 264, Pisum, 478 Pita flax, 612 Pitch, 598 Pitcher, 383 — of Cephalotus, 504 : — of Darlingtonia, 384 — of Discidia, 504 — of Marcgraavia, 290 —— of Nepenthes, 504 —— of Sarracenia, 504 —— plant, 578 Pith, 50, 52, 75 Pitted vessels, 20 Pittosporacee, 465 Pitus, 739 Placenta, 240, 315 — attachment of seeds to the, 329 — axile, 243 — central, 241 —— formation of, 241 —— free central, 243 —— marginal, 241 — parietal, 242 Placentaries, 240 Placentation, 243 Plaited, 11 Plane-trees, 594 —— of Scotland, 458 Planera, 585 Plante tristes, 262 Plantaginaceze, 559 Plantago, 560 Plantain, 608 Planting of trees, 78, 136 Platanacez, 593 Platanus, 594 Platylobez, 436 Platystemon, 433 Plectranthus, 554 Pleiotrachez, 18 Pleospora, 651 Plerandra, 509 847 Pleurenchyma, 16 Pleurisy-root, 536 Pleurocarpi, 643 Pleurorhizez, 340, 435 Plicate, rz Pliocene flora, 756 Plocaria, 655 Plum, 311, 485 Plumbaginacez, 559 Plumbago, 559 Plumose, 199 Plumule and radicle, 334 x : — or ascending axis, 334 Poa, 631 Pod, 312 Podalyriez, 478 Podocarp, 305 Podocarpus, 599 Podophyllum, 428 Podosperm, 253 Podostemacez, 588 Podostemon, 588 Pogostemon, 554 Poison-elder, 474 — ivy, 474 — oak, 474 —— sumach, 474 —— vine, 474 Poisoning plants in herbarium, 801 FoGens, effect of, on plants, 133 Poke, 563 Polar fossil flora, 756 — zone, plants of, 695. Polariser, 769 Polemoniacea, 541 Polianthes, 614 Pollard-trees, 113 Pollen, 216, 226 —— application to the stigma, 282 — carried by insects and wind, 284 —— coverings of, 230 —— duration of vita- lity of, 292 — grains, forms, and number of, 232, 282 — granules, 231 —— masses, 229 —— scattering of, 282 —— tube, 233 — tubes, extent to which they pene- trate, 295 —— tubes in gymno- sperms, 293 —— tubes, number of, 233 — utricle, 228 Pollinia, 229, 286 Polyadelphous, 219 Polyandrous, 216 Polycarpic, 359 Polycarpon, 445, 499 Polychroit, 609 Polycotyledonous, 338 Polyembryony, 331 848 Polygala, fertilisation of, 289 Polygalacez, 441 Polygamia, 563 Polygamous, 212, 367 Polygonacez, 563 Polygonal, 330 Polygonum, 564 Polygyneecial, 309, 316 Polynesian Region, 684 Polypetalous, 203 Polyphyllous, 190, 196 Polypodiez, 639 Polyporus, 650 Polysepalous, 196 Polyspermous, 312 Polystemonous, 215 Polytrichum, 643 Pomaderris, 472 Pome, 314 Pomee, 484 Pomegranate, 313, 492 Pompelmoose, 455 Pondweed, 626 Ponga, 639 Pontederia, 618 Pontederiacezx, 618 Poor man’s weather glass, 262, 559 Poplar, 592 Poppy, 433 — capsule of, 308, 315, Populus, 592 Porphyra, 655 Porrigophytes, 651 Portland dirt-bed, 749 — sago, 163, 685 Portugal Laurel, 486 Portulacacez, 445 Posterior applied to parts of a flower, 195 Posticze, 226 Potalia, 538 Potamez, 626 Potamogeton, 626 Potash and soda as manures, 138 —— in plants, 132 Potato, 313, 548 — disease, 398, 4o2 — eyes of, 47 —— starch in, 162 Potentilla, 486 Potentillez, 484 . Poteriez, 484 Pothocites, 742 Pothos, 625 Pounce, 599 Przfloration, 193 Przfoliation, 110 Preemorse, 47 Prangos, 507 Pretrea, 541 Prickles, 32 Prickly ash, 468 —— pear, soz — pole, 622 Primary colours, 390 — veins, 83 Primine, 254 INDEX. Primordial, 335 Primordial leaves, ror Primrose, 558 —— pin-eyed, 285 thumb-eyed, or thrum-eyed, 285 Primroses, fertilisation in, 285 Primula, 558 Primulacee, 557 Prince’s feather, 562 Pringlea, 437 —— antiscorbutica, fertilisation in, 284 Prinos, 530 Prionium, 619 Prismatical, 90 Prismenchyma, 4 Privet, 534 Procumbent, 45 Products and _ secre- tions of plants, 124, 161 —— azotised, 166 —— resinous, 169 Pro-embryo, 293 Progression of sap, 124 — of sap, cause of, 14 Proliferous, 119 —— bracts, 19 —— plants, 357 Propagation by graft- ing, 324 —— by leaves, 118 Propagulum, 113 Prosenchyma, 4, 16 Protandrous, 212, 286 Protea, 570 Proteacez, 570 Prothallus of ferns, 294 Protium, 475 Protococcus, 655 Protogynous, 212, 286 Protoplasm, 8 Pruning trees, 113 Prunus, 485 Psamma, 632 Psaronius, 732 Pseudo bulb, 47 Pseudospermous, 303 Psidium, 492 Psychotria, 512 Ptelea, 468 Pteris, 640 Pterocarpus, 480 Pterophyllum, 747 Ptychotes, 508 Pubescent, 33 Puccoon, 434 Puchurim beans, 569 Puff-balls, 651 Pulse, 479 Pulverised soil, 347 Pulvinus, 94 Pumpkin, 495 Punica, 492 Punctated woody tis- sue, 17 Purples, 403 Pursh’s floral Region, r Purslane, 445 Putamen, 3or Putty-wort, 605 Puya fibre, 584 Pycnides, 269 Pyrenz, 315 Pyrenean flora of Ire- land, 708 Pyrenees, flora of, 696 Pyrenocarpei, 646 Pyrethrum, 520 Pyrolez, 527 Pyrrhosa, 570 Pyrularia, 574 Pyrus, 486 Pythagorean bean, 432 Pyxidium, 315 QUADRANGULAR, 46 aiineate 223 uadrijugate, 104 Quadrilocular, 222, 241 osaiinactte, 198 ualea, 4 Guano 544 Juartine, 254 uassia, 469 Quaternate, 93 Quercitron, 595 Quercus, 595 Quillaia, 486 Quillaiez, 484 Quill-wort, 640 Quinate, 93 Quince, 314, 486 Quincuncial, 106 ae zstivation, 194 uincunx, 107 Quinine, 513 Quinoa, 562 Quinquangular, 46 Quinquecostate, 84 Quinquefid, 87, 197 Quinquepartite, 87, 198 Quintng 254 uisqualis, 489 Quitch-grass, 631 Quiver-tree, 615 RaceEME, 177 —— of capitula, 182 Races, 407 Rachiopteris, 732 Rachis, 172 Racodium, 650 Radical hairs, 34 ———Jeayes, tor, Radicle, direction of the, 343 —— or young root, 41, 334 Radicular merithral, 362 Radii, 180 Radiola, 463 Radish, 437 Rafflesia, 578 Rafflesiacez, 577 Rain, coloured, 282 Raisins, 462 Ramal leaves, ror Ramentaceous, 32 Rampion, 525 Ramsden eye-piece or ocular, 765 Ranunculacee, 426 Ranunculez, 427 Ranunculus, 427 —— fruit of, 310 Rape, 437 Raphe, 256, 329 Raphides, 11 Raspberry, 312, 485 Ratafia, 486 Ratsbane, 573 Rattan Palm, 622 Rattoons, 164 Ravenala, 608 Rays of light, effect in germination, 346 — effect on plants, 354 Reaumuria, 443 Receptacle, 173, 180 in composite, 181 of secretions, 12 Reclinate, 110, 339 Red cedar, 599 —— gum, red robin, red rust, and red rag, 399 — snow, 654 — whortleberry, 526 Reduplicate, 193 Reed mace, 686 Region of Amyri- dacez, 685 the Asiatic Islands, 684 — of Asters and Solidagos, 68: — of Cactacez and Piperacez, 686 —— of Cinchonas, 686 — of Epacridacee and Eucalypti, 689 — of Escalloniz and Calceolariz, 686 —— of Highlands of Mexico, 686 —— of Labiate and Caryophyllacez, 680 —— of Magnolias, 681 — of Mesembryan- thema and Stapelie, 689 —— of New Zealand, —— 9 I pai of Palme and Melastomacez, 687 —— of Saxifrages and Mosses, 67: — of, Shrebby Com- posites, 687 — of Ternstre- miacez, and Celas~ tracez, 682 — of Tree Rhodo- dendrons, 683 —— of Tropical Af- rica, 685 Region of Umbelliferze and Cruciferz, 680 —— of Zingiberacez, 683 Regma, 315 Regular monopetalous or gamopetalous co- rollas, 205 — polypetalous co- rollas, 204 Reindeer Moss, 647 Reinwardt’s fossil Re- gion, 684 Renealmia, 606 Reniform, 89 Replicate, 110 Replum, 244, 306, 315 Representative plants, 74 Reproduction, essen- tial organs, 173, 211 in Cryptogams, 233, 266 im phanerogams, 264, 281 " —— in Vallisneria, 282 Resedacez, 438 Resinous glands, 35 —— products, 16 Respiration of plants, 122, 155 Respiratory process in plants, three views of, 158 Restiacez, 687 Resting spores, 402 Restio, 687 3 Restricted plants, as regards distribution, 670 Reticulated vessels, 19 veins, 84 Reticulum, 32, 97 Retinaculum, 229 Retuse, 89 Revolute, 12 Rhabdocarpum, 746 Rhamnacez, 472 Rhatany, 442 Rheea fibre, 584 Rheum, 565 Rhexia, 489 Rhinanthez, 551 Rhinanthus _—_Crista- galli, fertilisation in, 290 Rhizanths, 142 Rhizobola, 452 Rhizocarpez, 640 Rhizocarps, reproduc- tion of, 279 Rhizogens, 37 Rhizome, 47, 113 Rhizomorpha, 650 Rhizophoracez, 488 Rhododendron, 527 Rhododendrons, ,tree, Region of, 683 Rhodolzena, 452 Rhodoleia, 504 Rhodosporez, 653 Rhodymenia, 655 INDEX. Rhubarb, 565 Rumex, 564 Rhus, 474 Ruminated albumen, Ribes, 502 Ribesiacez, soz Ribwort, 559 Ricciez, 644 Rice, 630 Rice-paper, 53, 509 Ricinus, 58z Rictus, 207 Rimmon, 492 Ringent, 198, 206 Ripening of fruits, 321 of seeds in gym- nosperms, 293 Robinia, 479 ? Rocambole, 615 Roccella, 647 Rock-rose, 439 Rohun bark, 460 Root, 37 — abnormal, 39 —— absorption by, 142 — adventitious, 39, 336 —— aerial, 39 —— buds on, 40 | —— climbers, 386 —— covering of, 4o — crown of, 37, 113, 146 —— forms of, 40 —— functions of, 43 —— grafting, 324 —— of acotyledons, 43 — of dicotyledons or exogens, 41 — of monocotyle- dons, 42 — parasitic, 142 — stock, 47 —— structure of, 38 Rootlets, 336 Rosa, 486 Rosacez, 483 Rosaceous corolla, 204 Rose, 312 —— apple, 492 — fruit of, 310 — of Jericho, 437 Rosewood, 481 Rosmarinus, 554 Rosemary, 554 Rostellum, ‘229 Rotate, 206 Rotation in cells, 152 — of crops, 133 Rottlera, 582 Roxburgh’s floral Re- gion, 683 Royal, or flowering fern, 639 ~ Royena, 628 Rubee, 484 Rubiacez, 511 Rudimentary leaves, 334 Rue, 467 _ Ruellia, 556 Ruiz and Pavon’s floral Region, 686 Ruizia, 589 3 | _ 333, | Runcinate, 87 | Runner, 113 | Ruppia, 626 | Rush, 619 | Rust, 141, 399 ) Rutaceze, 467 Rye, 630 — fruit of, 3x1 | —— spurred Kye, or. Ergot of, 400 Rye-grass, 631 | SABAL, 622 ' | Sabiaceze, 473 : Sabicu, 482 Saccate, 202 : Saccharine glands, 35 Saccharum, 63: Sack-tree, 587 Safflower, 520 Saffron, 609 Sagapenum, 507 Sage, 554 | Sageretia, 473 Sagittaria, 623 . Sagittate, 89, 203 Sago, 163, 601 —— fruit of, 311, —— Palm, 621 — Portland, 163 Saguera, 621 Sagus, 621 Saintfoin, 479 St. Helena, flora of, STA a St. Hilaire’s floral Region, 68 St. Ignatius’s Bean, 538 St. John’s Bread, 48r —— wort, 455 Sal, 451 Salacia, 471 Salep, 605 Salicacez, 59r Salicin, 166, 592 | Salicornia, 563 Saline plants, province saltie isburya, 600 Salix, 592 Salpiglossis, 551 Salsafy, 522 Salsola, 563 Salsola and Salicornia, province of, 680 Salvadoraceae, 334 Salver-shaped,. 205 Salvia, 554 Salvinia, 640 Samadera, 469 Samara, 317 Samaroid Achzenium, 3Ir Sambucus, 511 Samolus, 558 Samphire, 507 Samydacez, 573 849 Sandarach, 599 ) Sandbox, fruit of, 315 Sanguinaria, 434 | Sanguisorbeze, 484 ! Sanicula, 506 Santalacee, 574 Sap ascending, 146 — changes in com- position of, 145 —— circulation of, 124 — course of, in acro- genous plants, 148 — elaborated, ,de- scent of, 146 — wood, 55 Sapindacez, 458 Sapodilla, 531 Saponaria, 445 | Saponine, 445 Sapotacez, 530 Sappan-wood, 482 | Saprolegniez, 653 — reproduction of, 144, 272 Sapucaia-nuts, 492 Saurauja, 452 Sarcinula, 655 Sarcocarp, 301, 312 Sarcocolla, 572 Sarcoderm, 327 Sarcoleena, 452 Sarcolobez, 476 Sarcophyte, 577 Sarcosperm, 327 Sargassum, 654, 700 Sarmenta, rat Sarmentum, 45 Sarnian Flora, 706 Sarracenia, 383 Sarraceniacez, 432 Sarsaparilla, 617 Sarza, 417 Sasanqua Tea, 453 Sassafras, 568 Satin-grass, 632 Satin-wood, 460 Satureia, 554 Saururacez, 590 Saururus, 590 Sauvagesiez, 440 Savin, 599 Savoury, 554 Savoys, 437 Saxifragaceze, 502 —— Region of, 679 Scabiosa, 515 Scabrous hairs, 32 Scaevola, 523 Scalariform vessels, 19 Scale-mosses, 643 Scales, 99, 104, 109, Igo, 20! — of Pine-apple, 190 Scammony, 544 Scandent, 45 Scandinavian flora of Britain, 709 | Scape, 173 | Scar, 82, 95. Sandal-wood, 574 I | Scarlet-runner,. 481 850 Scepacez, 580 Scheuchzeria, 623 Schinus, 474 Schizaea, 639 Schizanthus, 551 Schizopetalon, 435 Schizandra, 429 Schizocarp, 306 Schoenus, 628 Schouw’s phyto-geo- graphic regions, 679 Scilla, 614 Scillez, 614 Scions, 325 Scirpus, 628 Scitaminez, 605 Scleranthez, 499 Scleria, 628 Sclerogen, 9 Scolymus, 520 Scorodosma, 507 Scorpioid, 185 Scorzonera, 522 Scotch fir, 599 —— myrtle, 592 —— thistle, 520 Scottish mountains, flora of, 707 Screw-pine, 624 Scrophulariacez, 551 — fertilisation in, 289 Scurvy-grass, 437 Scutellaria, 554 Scythian or tartarian lamb, 640 Scytosiphon, 654 Sea Buckthorn, 571 Sea-kale, 437 Sea-pink, 559 fertilisation of, 291 Seaside grape, 565 Sea-weeds, 652 —— mannite in, 165 —Mmanuring with, 140 Sebesten-plums, 545 Secale, 630 Secundine, 253 Securidaca, 442 Sedges, flowers of, 208 Sedum, 499 Seed, 298, 325 —— composition the, 343. — coverings of, 326 —— dissemination of, of 343 — forms of, 330 —— maturation and functions of the, 343 — modes of trans- porting, 348, 803 —— number of, 344 — of gymnosperms, 293. —— position of, 330 —— sowing of, 345 ——vitality of, 346, 350 Seedless fruits, 319 Selagineae, 558 Selaginella, 640 INDEX. Selaginella, colouring matter of, 392 —— reproduction of, 278 Selaginites, 733 Selago, 555 Self-fertilisation, 284 Semecarpus, 474 Semi-anatropal ovule, 256 Semi-equitant, 340 Seminal leaves, 339 —— lobes, 339 Seminude, 252, 326 Sempervivum, 499 -—— province of, 680 Senebiera, 435 Senecio, 520 Senega or Seneka root, 442 Senegal gum, 163 Senftenbergia, fructifi- cation of 730 Senna, 482 Sensitive plants, 376 —— effect of anzesthe- tic agents on, 386 —— effect of light and chemicals on, 377 Sepals, 195 —— forms and size of, 197 7 Septate, 234 Septemfid, 87 Septempartite, 87 Septenate, 93 Septicidal, 304 Septifrugal, 305 Septulatze, 436 Septum, 222, 224, 241 Sequoia, 598 — fossil, 753 Sericeous, 33 Serrate, 86 Sesamum, 541 Sessile glands, 34, 35 —— leaf, 82 Sesuveze, 500 Setaceous, 32 Sete, 32, 250 Setaria, 631 Setose, 32 Sexes of plants, 264 Seychelles palm, 621 Shaddock, 314, 454 Shaked, 485 Shallon, 527 Shallot, 615 Shamrock, 465, 479 Shea butter, 532 Sheath, 336 — medullary, —— of leaf, a a Sheathing bracts, r9z Sheep’s sorrel, 564 She-oak, 593 Shesh, 585 Shifting crops, 134 Shikmim, 586 Shittah-tree, 482 Shola, 53 Shoom, 615 Shorea, 451 Short-styled, 285 Shrubs, defined, 46 Side grafting, 325 —— saddle flower, 432 Sideze, 447 Sigillaria, 736 Sileneze, 445 Silica, 129, 131, 135 Silicula, 315 Siliculosze, 436 Siliqua, 306, 315 Siliquose, 436 Silk cotton, 448 —— plant, 536 Silver fir, 599 — grain, 59 - — oak, 570 —— tree, 570 Simarubacez, 468 Simple leaves, 85 Sinapis, 435 Siphocampylos, 525 Siphonia, 582 Sissoo, 480 Sisyrinchium, 608 Sium, 507 Size of trees, 360 Skirret, 507 Skorodon, 615 Skunk cabbage, 625 Sleep of plants, 375 Slipper-like, 207 Slips, 325 Sloe, 486 Smeathmannia, 497 Smilacez, 617 Smilax, 617 Smith and Beck’s mi- croscope, 770 Smut, 141, 399 —— balls, 399 Snake-gourd, 496 — nut, 459 — root, 448, 459 —— wood, 538, 587 Snowball, 5rz Snowberry, 512 Snowdrop, 612 —— trees, 529 Snowflake, 612 Soapwort, 458 Soboies, 47, 113 Soda in plants, 132 Soil as influencing plant distribution, 662 Soil, mode of estimat- ing the nature of, 135 —— pulverised, 347 Soils, chemical compo- sition of, 134 Solanacez, 547 Solanum, 548 Soldanella, 558 Solenostemma, 536 Solid oils, 167 SolaaEns Region of, ir Sollya, 466 Solomon’s seal, 47 Solutions used for poi- soning and preserv- ing plants, 801, 802 Sonchus, 520 Sooranjee, 514 Soot as a manure, 138 Sorghum, 630, 632 Sori, 638 Sorosis, 316 Sorrel, 564 Souari-nuts, 454 Sour-sop, 430 South America, flora of highest parts of, 686 South American flora, extra-tropical, 687 Southern wood, 52 Sow-bread, 558 Sowing of seeds, 345 Soymida, 460 Spadix, simple, 179 Sparganium, 625 Spatha or Spathe, 191 Spathelle, 192 Spathodea, 540 Spathulate, 89 Spawn, 357 Spearmint, 554 Species, 406 ——number of known, 405 ; — and sub-species, definition of, 406 — variation in, 407 Specific names, 410 Specimens preserved in a moist state, 802 Spelt, 630 Sperm cells, 281 Spermacoce, 512 Spermagones, 268 Spermatia, 268 Spermatozoa, 265 Spermatozoids, 265 Spermoderm, 327 Spherenchyma, 3 Spheeria, 651 Spheerococcus, 655 Sphzeroplea, reproduc- tion of, 271 Spheerozyga, 655 Sphagnez, 643 Sphenophyllum, 738 Sphenopteris, 731 Spherical, 284 : Spherical aberration, 762 Spice-wood, 569 Spiderwort, 623 Spigelia, 539 Spike, 178 —— compound, 182 Spikelets, 179, 208 Spikenard, 515 Spinach, New, Zea- land, 520 Spinacia, 562 Spar: 562, Spindle tree, 328, 471 Spines, 119 Spireeeze, 484 234, Spiral cycles of leaves, To: 3 leaves, g1 —— twiners, 386 —— vessels, 17 Spirals in fir cones, ros Spirolobez, 435 Spitzbergen, fossil _ plants of, 738, 755 Splachnum, 643 Spondias, 474 Sponea, 585 Spongioles, 38 —— absorption by, 142 Spontaneous genera- tion, 15 Sporangia, 250 in coal, 729 Sporangiferous, 280 Spore, compound, 268 Spore of-acotyledons, Spores, 250 moving, 265 Spores of fungi, rest- ing, 402 Sporidium, 335 Sporocarp, 640 Sporophores, 647 Sprengelia, 528 Spruce, 599 — cone of, 317 Spurges, 579 Spurge-laurel, 572 Spurious dissepiments, 244 Spurred, 198, rye, 400 Squamz, 1g0, 208 Squamash, 615 Squash, 495 Sguill, 624, 615 Squirting cucumber, Staavia, 504 Stachytarpheta, 556 Stackhousiacez, 470 Stagmaria, 474 Stamens, 191, 212 — abortive, 219 — cohesion of, 227 — _ development, structure, and form of, 214 — irritable, 283 — length of, 227 —— long, .short, and medium, 285 — of grasses, 224, 656 — position of, 212, 215 Staminal degenera- tions, 369 Staminiferous, 264, 368 Staminodes, 219 Stamminodium, 36, 227 Standard, 205 , Stangeria, 600 Stanhopea, 604 Stapelia, 536 212, INDEX, Sapske fertilisation of, 284 —— Region of, 689 Staphyleaceze, 472 aera 429 —— apple, 532 Star-like, a Starch, ro, 162 — .changed into sugar, 163, 260 — in fruits, 321 — in seeds, 163, 350 Statice, 559 Statistics of vegeta- tion, 677 Stavesacre, 427 Stearic acid, 168 Stearin, 168 Stearoptene, 169 Steeping seeds, 140 Stelis, 604 Stellate, 206 —— hairs, 31 Stem, 44, 335 —— acotyledonous or acrogenous, 49 — aerial, 46 —— anomalous exo- genous, 60 : —— creeping, 114 — exogenous or di- cotyledonous, 49 — herbaceous, 50 hypocotyledon- ary, 41 —— internal structure of, 49 —— ligneous, 50 — monocotyledon- ous or endogenous, 49, 64 | —— parasites, 142 —— protuberances on, 46 — special functions of, 75 —— subterranean, 46 Sterculiaceze, 448 Sterigmata, 268 Sterile, 227, 368 Sternbergia, 612, 741 Stevensonia, 621 Sticta, 647 Stigma, 235, 248, 282 — development, 290 —— of Campanula, 290 —— sensitive, 248 —— structure and posi- tion of, 248 Stigmaria, 734 Stilago, 588 Stillingia, 582 Stings, 34 . Stinking rust, 399 Stipe, 44 Stipels, 99 Stipitate, 180, 240 — glands, 34 Stipulate, 97 Stipules, 82, 97 — forms of, 99 Stock, 44, 323 Stomata, 28, 80 — development and ‘forms of, 29 —— in anthers, 220 — number in square inch of surface, 30 Stonecrop, 499 Stone of fruit, 302 Stone-pine, 599 Storax, 529 Stramonium, 549 Strap-shaped, 207 Stratiotes, 602 Strawberry, 312, 485 — fruit of, 310 —— tree, 527 Strelitzia, 608 Streptocarpus, cotyle- dons of, 338 Strobilus, 179, 190, 317 Strophanthus, 537 Strophiolate, 329 Strophioles, 329 Struma, 95 Strumose, 218 Strychnia, 538 Strychnez, 538 Strychnos, 538 Stupose, 33, 217 Style, 246 — feathery, 310 — form and struc- ture of, 236, 247 —— length of, 248 — of Campanula, 290 — of Goldfussia, 290 —— position of, 246 Stylewort, 523 Stylidiaceze, 523 Stylopod, 506 Stylospores, 269 Styphelia, 528 Styracaceze, 529 Styrax, 529 Sub-arctic zone, plants of, 693 Sub-classes, 411 Suberic acid, 168 Suberous layer, 58 Sub-genus, 410 Sub-orders, 410 Subordination of cha- racters, 416 Sub-species, 409 Subterranean buds, rz. Subtropical zone, plants of, 693 Subulate, 89, 216 Succulent. fruits, 309, 3II, 313 leaves, go —— peduncle, 173 Suckers, 114 —— of Dodder, 4o Suffrutex, 46 Suffruticose, 46 Sugar, 164 —— beet, 164 — cane, 164, 631 —— grape, 165 —_— nes of, 164 leaf- 851 Sugar in fruits, 321 —— in seeds, 350 —— manna, 165 —— maple, 164 — Muscovado, 164 —starch changed to, 163 Suke, 586 Sulphates as a manure, 13 Sulphur showers, 282 Sulphuretted hydro- gen, effect on plants. 160 Sulphurous acid gas, effect on leaves, 160 Sumach, 474 -..- Sumatra camphor, 451 — flora of, 684 Sumbul root, 508 Sundew, 441 Sunflower, 52z Sun spots as affecting vegetation, 399 Superior applied to the Parts of a flower, 195 Supervolute, 1zz Suppression of organs, 395 Supradecompound, 92 Surculi, 114 Surinam medlar, 531 Suspended, 257, 330 Suspensor, 253 Sutural, 303 Sutures, 224, 240 es nest, 655 wamp-pine, 599 —— Sassafras, 429 Swartzia, 478 - Swartz’s Region, 687 Sweet bay, 567 — cane, 632 — fern, 592 — flag, 625 — sop, 430 —— vernal grass, 631 Swietenia, 460 Sycamine tree, 586 Sycamore, 458 —— fruit of, 311 Sycamorus, 586 Syconus, 361 Sylhet varnish, 474 Symbols, 412 — and abbreviations, 830 —for number of parts of the flower, 364, 2 — for unisexual flowers, 367 Symmetrical, 203 Symmetry, 363 — causes of want of, 365 ——in acotyledons, 365 —— in Crucifere, 436 —jin dicotyledons, 364, — in monocotyle- dons, 365 852 Symplocarpus, 625 Symplocez, 529 Synanthere, 517 Synantherous, 227 Synaptase, 166 Syncarpous, 239 — fruits, 313 —— indehiscent fruits, 333 Syngenesious, 227 Synochreate, 98 Syringa, 490, 533 System, Linnean, 413 — natural, 415 Systematic Botany, Taxonomy, classifi- cation of plants, 405 TABASHEER, 131 Tabernzemontana, 537 Tacamahac, 592 Tacsonia, 498 Talauma, 429 Talinum, 446 Tallow-tree, 582 Tamar, 621 Tamaricacee, 442 Tamarindus, 481 Tamarisk, 443 Tanecium, 541 Tangena nut, 537° Tanghinia, 537 Tangle, 655 Tannic acid and Tan- nin, 170 Tansy, 521 Taphrenchyma, 20 Tapioca, 163, 582 Tap-root, 40 Tapura, 573 Taraxacum, 521 Tarragon, 521 Tartarian lamb, 640 Tartaric acid, 170 Tawhara, 624 Taxinee, 598 Taxodium, 598 Taxonomy, 405 Taxus, 600, 634 Tea, 452 Teak-tree, 555 Teak of Africa, 583 Teashur, 582 Teazel, 515 Tecoma, 541 Tectona, 555 Teel seeds, 541 Teenah, 586 Tegmenta, 109 Telegraph plant, 377 Telfairia, 494 Temperate zone cooler, plants of, 693 — warmer, plants of, 693 ne Temperature, altitudi- range of, 661 — effects of, in the distribution of plants, 658 — requisite for ger- munation, 345 INDEX. Temperature of plants, 88 3 Tendril, 97, 120, 174 —— bearers, 38 — coiling of, 385 — homologues of, 120 Tephrosia, 480 Teratology, 365° cohesion and ad- hesion, 370 —— multiplicationand chorization, 371 Tercine, 254 Terminal, 108 —inflorescence, 175 Terminalia, 489 Terminology, 406 Ternate, 93 Ternstreemiaceze, 452 —— Region of, 682 Tertiary fossils, 751 — flora of Europe, 756 : Tesselated epicarp of sago, 311 Testa, 327 Testudinaria, 6x1 Tetracera, 428 Tetradynamous, 228 Tetragonal, 363 Tetragonia, 500 Tetrameles, 578 Tetramerous, 363 Tetrandrous, 216 Tetranthera, 567 Tetrapetalous, 203 Tetraspore, 273, 335 Tetratheca, 442 Tetrathecal, 222 Teucrium, 554 Thalamiflore, 425 Thalamifloral, 214 Thalamus or Torus, 174, 191 Thallogena:, 644 Thallogens, 44, 635 — root of, 37 ' Thallophyta, 44, 635, 64. Thallus, 44 Thaumatopteris, 747 Thece, 250, 267 Thecaphore, 240 Theine, 452, 530 Theobroma, 450 Theophrasta, 531 Thesium, 574 Thistle, 520 Thorns, rr ‘Thorn apple, 54 Thorough-draining, 348 Thnift, 559 Ba ites, 749 Thuja, 599 Thunbergiez, 556 Thunberg’s floral Re- gion, 689 ~ Thus, 599 Thyme, 554 268, Thymeleacex, 571 Thymus, 554 Thyrsus, 184 Ti, 616 Tigellary, 82 Tigelle, 334 Tiglium, 58: Tiliaceze, 450 Tillandsia, 613 | Timothy grass, 631 Tinospora, 430 Tissues, 1, 16, 17 arrangement of, 23 Tobacco, 550 Toddalia, 468 Tofieldia, 616 Tomato, 549 Tomentose, 33 Tomentum, 33 Tonka-bean, 480 Tongue-grafting, 325 Toothache-tree, 509 Toothwort, 551, 559 Tormentil, 48 Tornelia, 625 Torreya, 598 Torrid zone, plants of, 2 Tortoise plant, 612 Tortula, 643 Torula, 649 Torus, 174, 191 Tous-les-mois, 607 Towel-gourd, 496 Toxicophleea, 537 Trachez, 18 Trachenchyma, 17 Trachylobium, 482 Tradescantia, 623 —— rotation in, 153 Tragacanth, 163, 479 Tragopogon, 522 Transpiration, 121 Transudation, 15 Transverse dehiscence, 225, 307 ; Trapa, 493 Traveller’s tree, 608 Tree-beard, 613 Tree-ferns, 638 —— Region of, 698 Tree-lilies, 610 Tree-nettle, 584 Trees, branching of, 45 —— defined, 46 — on the Grimsel, as regards altitude, 662 —— planting of, 78 —— size and age of, 360 Trefoil, 479 Trema, 585 Tremandracez, 442 Triadelphous, 219 Triandrous, 216 Triangular, 46, 330, B03 ie cae Triassic fossils, 746 Tribes, 238, 410 Tribulus, 466 Tricerastes, 578° Trichadenia, 440 Trichilia, 460 Trichodesmium, 655 Trichogynium, 272 Trichomanes, 639 Trichophore, 273 Trichosanthes, 496 Trichotomous cyme, 183 Tricoccous, 306 Tricostate, 84 Trientalis, 558 Trifid, 87, 197, 248 Trifolium, 479 Triglochin, 623 Trigonal, 363 Trigonocarpum, 746 Trigonocarpus, 741 Trigonous, 46 Trijugate, 104 Trilamellar, 249 Trilliaceze, 617 Trillium, 618 Trilobate, 249 Trilocular, 24x Trimerous, 363 Trimorphic flowers of Lythrum, 285 Triceciously-hermaph- rodite, 286 Tripartite, 87, 198, 248 Tripinnate, 92 Tripinnatifid, 87 Tripe de Roche, 647 Tripetalous, 203 Triplosporites, 733 Triptilion, 520 Triptolomea, 48 Triquetrous, 46 Trisepalous, 197 Tristichous, 103 Triternate, 93 Triticum, 630 Trivial names, 410 Trixis, 520 Tropzolaceze, 465 Trophosperm, 253 Tropical zone, plants of, 692 Trochodendron, 429 Truffle, 649 Triuris, 623 Trumpet-leaf, 432 Trumpet-flower, 540 Trumpet-wood, 88 Truncate, 89, 198 Truncus, 44 ryma, 312 Tsuga, 598 Tube of calyx, 198° Tuber, 47, 114, 649 —— chine, 617 Tubercular, 40 Tubercularia, 649 Tuberose, 614 Tubular, 206 Tubuliflore, 519 Tulip, 614 Tulipez, 614° Tulip-tree, 429 Turbinate, 198 Turio, 114 Turmeric, 606 Turneracez, 498 Turnip, 437 Turnsole, 58 Turn-table Se micro- scopic preparations, 786 Turpentine, 599 hian, 474 Tussac-grass, 631 Tussilago, 520 Tutsan, 455 Twining plants, 385 — stems, 45 Twisted, 40, 112 —— estivation, 193 Tylophora, 536 Tylosis, 22 Tyndaridea, 655 Typha, 626 Typhinez, 628 Upora, 602 Usgni, 492 Ulex, 481 Ullucus, 446 Ulmacez, 585 Ulmine, 134 Ulmus, 585 Ulodendron, 734 Ulva, 655 Umari, 480 Umbel, 180 Umbelliferze, 505 fruit of, 312 —— Region of, 680 Umbellules, 180. Umbilical cord, 253 Umbilicaria, 646 Umbilicus, 329 Umiri, 460 Unazotised matter in plants, 167 Uncaria, 514 Uncinate hairs, 32 Undershrub, 46 Undulated, 90 Unequally pinnate, 93 Unguiculate, 201 Unguis, 201 Unicorn plant, 541 Unicostate, 84, 92 Unijugate, 92, 104 Unilateral, 248 —— inflorescence, 184 Unilocular, 222, 242, 299 Uniparous cyme, 183 Unipetalous, 203 Unisexual, 212, 367 Univalvular, 303 Unlining, 371 Unsymmetrical, 364 Upas Antiar, 587 Upas Tieuté, 538 Urania, 608 Urceola, 537 Urceolaria, 646 Urceolate, 206 203, Uredo, 649 INDEX. Urginea, 614 Urn-mosses, 643 —— shaped, 206 Urostigma, 586 Urtica, 584 Urticacez, 583 Utricle, 3, 8, 228, 310 Utricularia, 557 Uva, 313 Uvaria, 429 Uvulariez, 616 VACCINIACEA; 525 Vacoa, or Baquois, 624 Vagina, 82, 97, 337 Vaginula, 64 Vahea, 537 Valerian, 515 —— Greek, 542 Valerianacez, 514 Valerianella, 515 Vallecule, 506 Vallisneria, 602 —— reproduction in, 282 —— rotation in cells of, 152 Valonia, 595 Values of different or- gans, 416 Valvate, rz1, 193 Valves, 303 4. Vanilla, 605 Varieties, 407 Variolaria, 647 Varnishes, 474 Varronia, 545 Vascular bundles acrogens, 71 —— bundles in calyx, in 197, bs —— bundles in endo- gens, 67 -—— bundles in exo- gems, 53 —— tissue, 16 Vasiform tissue, 20 Vateria, 452 Vaucheria, 269 Vaucheriez, 653 Vegetable brimstone, 64x, —— ivory, 333 marrow, 496 —— wax, 168 Vegetation, altitudinal range of, 695 —— general pheno- mena of, 374 — influenced by ex- ternal agents, 657 —— of the globe, its origin, 672 Veinless, 83 | Veinlets, 84 Veins, 83 Velleia, 523 Vellozia, 6z0 Velum, 647 Velutinus, 33 Velvety, 33 Venation, tabular ar- rangement of, 84 Ventral, or outer su- ture, 240, 303 Venus’s fly-trap, 380, 44 Veratreze, 616 Veratrum, 616 Verbascum, 551 Verbena, 555 Verbenacez, 555 Verjuice, 462 Vermiform vessels, 20 Vernal grass, 631 Vernation, 110 Vernonia, 520 Veronica, 552 Verruce, 36 Versatile, 224 Verschaffeltia, 621 Verticil, 102 Vertical theory of wood formation, 76 Verticillaster, 184 Verticillate, 102 Vervain, 556 Vesicle, embryonal, 293 Vesicles, 2 Vesicular, 200 Vesicular glands, 36 Vessels of plants, 16 ——laticiferous, move- ments in, 145 Vetivert, 632 Vexillary, 195 Vexillum, or standard, 205 Viburnum, 511 Victoria, 432 Victor’s Laurel, 567 Villi, 30 Villous, 33 Vinca, 537 Vine, 460 —— disease, 400, 403 Violaceze, 440 Violet, 440 Virginia, | Pennsyl- vania, and New York, flora of, 68x Virginian Creeper, 462 — Snake-root, 577 Viscum, 575 Vismia, 456 Vitaceze, 460 Vitality of seeds, 346 Vitellus, 328 Vitex, 556 Vitte, 13 Viviparous, 357 Viviparous bracts, 191 Vivianiacee, 463 Vochysiacez, 488 Volatile oils, 168 Volkmannia, 738 Voltzia, 747 Volva, 647 WACHENDORFIEZ, 614 ‘Wagenboom, 570 853 Wahlenberg’s floral Region, 679 Wake-robin, 625 Walchia, 745 Wallflower, fruit of, 315 Wallich’s floral Re- gion, 683 Walnut, 311, 596 Ward’s cases, 160, 349 Warts, 36, 224 Water-beans, 432 Water-chestnut, 493 — dock, 564 —— dropwort, 508° — flannel, 655 — hemlock, 508 —— in plants, 167 —_ lilies, 432 — melon, 495: —— net, 655 —— pepper, 443, 564 —— pitcher, 432 — plantain, 623 — shield, 432 — tree, 608 Watson’s British floral provinces, 704 — climatic or as- cending zones of ve- getation in Britain, 733 — division of areas of British plants, 7o2 Wattle-trees, 482 Wavy, 90, 203 Wax-flower, 536 — myrtle, 592 —— palm, 622 Wax, vegetable, 168 Way-bred, 560 Wealden flora, 750 Weinmannia, 504 Weld, 438 Wellingtonia, 598 Welwitschia, 600 — permanent cotyle- dons of, 338 West Indian Region, 68 Wetherellia, 751 eat, 630 — barley, and oats, fertilisation of, 634 —— nutritive . matter of, 166 Wheel-shaped, 206 ip-grafting, 325 White Hellebore, 616 Whorl, 102 Whortleberry, 526 Wig-tree, 474 Wild-cotton, 536 — ipecacuan, 536 Willdenovia, 627 Williamson on cala- mites, 737 — on the carbonifer- ous flora, 734 Williamsonia, 749 Willows, 592 854 INDEX. Willow-strife, 487 Wood, durability of, 55] Xanthophyll, 391, 392 | Zanthoxylacez, 468 Wilson on fertilisation] —— formation of, 76 | Xanthorrheea, 615 Zanzibar copal, 482 of wheat, oats, and] Woodruff, 514 Xanthoxylacezx, 468 Zea, 630 barley, 634 Woody layers, 53 Xerophilous plants, 663] Zebra-plant, 607 Wimble or peg graft-| —— nodules, 116 Xylopia, 430 — wood, 476 ing, 325 Woodsia, 639 Xyridaceze, 618 Zieria, 467 Winged fruits, 31x Wood-sorrel, 464 Zingiber, 605 Wings of corolla, 205 | Woolly, 33 Yam, 611 Zingiberacez, 605 Winter’s-bark, 429 Woorali poison, 538 Yew, 600 —— Region of, 683 Winter cherry, 549 Wormskioldia, 498 —— age of, 361 Zizania, 631, 634 —— green, 527 Wormseed, s2r —— embryo sac of, 292| Zizyphus, 473 Winterez, 429 Wormwood, 521 —— fruit of, 317 Zones of wood, 53 Wistaria, 479 Wrightia, 537 Yucca, 615 Zoophilous, 284 Witch-hazel, 504 Wukkum-wood, 482 Zoospores, 265 Witsenia, 608 Wych elm, 585 ZAIT, 533 Zostera, 626 Woad, 437 Zamia, 600 Zosterites, 753 Wollaston’s doublet,| Kanruic series of co-| Zamites, 747 Zygophyllacee, 466 763 lours, 393 Zannichellia, 626 Zygospore, 268 THE END. Printed by R. & R. Crank, Edinburgh, BALFOUR’S BOTANICAL WORKS. In one vol., Third Edition, royal 8vo, pp. 1117, with 1800 Illustrations, price 21s. CLASS-BOOK OF BOTANY. Being an Introduction to the Study of the Vegetable Kingdom. By J. HUTTON BALFOUR, MD., F.RS,, Professor of Medicine and Botany in the University of Edinburgh, Regius , Keeper of the Royal Botanic Garden, and Queen’s Botanist for Scotland. (May also be had in two Parts, price 21s.) “Tn Dr, Balfour’s ‘ Class-Book of Botany, the author seems to have exhausted every attainable source of information. Few, if any, works on this subject contain such a mass of carefully collected and condensed matter, and certainly none are more copiously or better illustrated.” — Hooker's Journal of Botany. “Professor Balfour's ‘ Class-Book of Botany’ is too well and favour- ably known to botanists, whether teachers or learners, to require any introduction to our readers, It is, as far as we know, the only work which a lecturer can take in his hand as a safe text-book for the whole of such a course as is required to prepare students for our University or medical examinations, Every branch of Botany, structural and morphological, physiological, systematic, geographical, and palzonto- logical, is treated in so exhaustive a manner as to leave little to be desired. “The work is one indispensable to the class-room, and should be in the hands of every teacher.”—Wature. “One of the best books to place in the hands of a student,”— Annals of Nat. History. “One of the most complete and elegant class-books on Botany which has been published. It contains all that a student may require, both in description and illustration.”—Lancet. BALFOURS BOTANICAL WORKS. Uniform with “Class-Book of Botany,” In one Vol., illustrated with four Lithographic Plates and upwards of 100 Woodcuts. Price 7s. 6d. INTRODUCTION TO THE STUDY OF PALZONTOLOGICAL BOTANY. “Professor Balfour has published, in the form of a separate work, and with additions, that portion of his Class-Book of Botany which contains an introduction to fossil botany. The importance of the study of fossils, particularly in their relations to time and space, is now universally admitted as being essential to a thorough study of all the natural sciences; and geologists, especially, admit that, but for paleontology, their science would not have made such progress as it has ; and such a book as this must be considered as a valuable aid to the study. It, of course, presupposes acquaintance with botany pure, or the botany of the present time, for only he who is intimate with existing flora and fauna has a right to decide in regard to fossils, and is therefore intended only for advanced students in botany. On a work of this kind we cannot give a detailed criticism. We may mention, however, that Professor Balfour takes Brogniart’s division of the fossil flora into three great epochs :—1. The reign of acrogens; 2. The reign of gymnosperms; and 3. The reign of angiosperms. The first should be particularly interesting to Edinburgh students, embracing, as it does, the silurian, carboniferous, and permian epochs ; the vicinity of our city being particularly rich in carboniferous fossils, which, moreover, belonging chiefly to the fern class, have a special value from their retaining their forms better than cellular plants, and the cellular portions of vascular plants. The portions of the book which refer to coal will also be found interesting by a Iarger circle of students than that composed merely of paleontological and botanical students. The fact that Professor Balfour is the author of this book is a sufficient guarantee of the excellence of its method, the accuracy of its information, and the lucidity of its style ; and we have no doubt that it will serve the purpose for which its author designed it—namely, of encouraging students to take up and peruse with enthusiasm the subject of fossil botany. We may add that, in point of typography and wealth of illustrations, it is equal, if not superior, to any book of the kind we have seen.” —Edinburgh Courant, BALFOURS BOTANICAL WORKS. “ Although the literature of Paleontological Botany is very extensive, it consists either of costly and voluminous works or papers scattered widely through the Transactions of various Societies, none of which are adapted to the use of those students who wish to extend their study of general botany to this interesting but less known branch of the subject. From every point of view the study of the fossil flora of the globe must be of great interest ; it widens the field of the modern botanist ; it is absolutely essential to the geologist ; and to the general student it gives much information regarding the former history of the globe and the nature of its products. Take, for instance, Coal, and we find in Professor Balfour’s manual the following interesting information :— “