tate College of Agriculture At Cornell tlmberSitp Stftaca. JJ. g. HtbrarpDate Due OCT 19 1950 ITT wsr 6 I0ct2 css:' IV! av: 90 1 Wl 0/ flW ruovT-! >9K Jan 5 6 ; ^amMOHaSSS* t Cornell University Library QK 45G77ln 1857 Introduction to structural and systemati 3 1924 001 719 321 31924001719321INTRODUCTION TO STRUCTURAL AND SYSTEMATIC / BOTANY, AND VEGETABLE PHYSIOLOGY, BEING A FIFTH AND REVISED EDITION OF THE BOTANICAL TEXT-BOOK, ILLUSTRATED WITH OVER THIRTEEN HUNDRED WOODCUTS. By ASA GRAY, M.D., FISHER PROFESSOR OF NATURAL HISTORY IN HARVARD UNIVERSITY. NEW YORK: IVISON, PHINNEY, & CO., 48 & 50 WALKER STREET. CHICAGO: S. C. GRIGGS & CO., 39 & 41 LAKE STREET. PHILADELPHIA : SOWER, BARNES, & CO., AND J. U. LIPPINCOTT & CO. BOSTON : BROWN, TAGGARD, & CHASE. CINCINNATI: MOORE, WILSTACH, KEYS, & CO. SAVANNAH : J. M. COOPER & CO. NEW ORLEANS : BLOOMFIELD, STEEL, & CO. ST. LOUIS : KEITH & WOODS. DETROIT : F. RAYMOND & CO. 1 8 6 2,.Entered according to Act of Congress, in the year 1857, by IVI SON AND PH IN NET, in the Clerk’s Office of the District Court for the Southern District of New York. University Press, Cambridge: Electrotyped and Priuted by Welch. Bigelow, & Co.PREFACE. This compendious treatise is designed to furnish classes in the higher seminaries of learning, colleges, and medi- cal schools, as well as private students generally, with a suitable text-book of Structural and Physiological Botany, and a convenient introduction to Systematic or Descriptive Botany, adapted to the present condition of the science. The favor with which the former editions have been re- ceived, while it has satisfied the author that the plan of the work is well adapted to the end in view, has made him the more desirous to improve its execution, and to render it a better exponent of the present state of Botany. In this view, the structural and physiological part of the work, and the chapters on the Principles of Classification and of the Natural System, have been again almost entirely rewritten, and such changes made as the advanced state of our knowl- edge required, or the author’s continued experience in teaching has suggested. This has been done without in- creasing the extent of this part of the volume, which, con- sidering the limited time devoted to the study in our col- leges, &c., is found to be as full as is desirable for a text- book. Being intended as a manual for instruction merely, the Illustrations of the Natural Orders, which form the prin- cipal portion of the systematic part of the work, are brief1Y PREFACE. and general. Such a sketch, however amplified, could never take the place of a Flora, or System of Plants, but is de- signed merely to give a general idea of the distribution of the vegetable kingdom into families, 3 °° o°-i 111'1 3 0„ ^ sSTtt j> OO, a- » [s° oo0 o 3 and of the four in Fig. 18, forms a part of the thichness of the coat of each, or is destroyed by the distention, or else (as in the present instance) is dissolved into a jelly A slight modification of this process occurs in 36. Free Cell-Multiplication within a Mother-Cell, which is intermediate in character between original cell- formation and ordinary cell-multi- plication. Here the whole contents of a living cell, by constriction or » <>'!l infolding of the primordial utricle, divide into two or four parts (as in Fig. 81—83), and these may be again divided; — each portion has a coat of cellulose deposited over its surface, and thus so many sep- arate cells are produced, lying loose in the cavity of the mother-cell, whose thin and now dead cellulose-wall, which is all that is left of it, usually disappears sooner or later, or is broken up by the growth of the new crop of cells within. In this w ay are formed the grains of pollen in the anther, and the spores, or bodies which answer to seeds, in the higher grades of Flowerless Plants. 37. Cell-Growth. By appropriating assimilated matter, the young cell increases in size until it attains its full growth; its W’alls, as they expand and enclose a greater space, not diminishing, but rather increasing in thickness. Therefore it not merely enlarges, but grows. If it grows equally in all directions, and is not pressed upon on any side, it keeps a spherical form; if it grows more in one direction than in any other it becomes oblong or cylindrical. In this way a cell is sometimes drawn out into a slender tube; of which the fibres of cotton, and the cells of fibrous bark (Fig. 49) are good examples. In the simplest plants, cells sometimes continue to elongate almost FIG 20. The branching summit of a plantlct of Conferva glomerata, magnified; after Mohl The plant consists of a row of cells, filled with green grains floating in liquid : tho long cell at the upper end is seen in the process of dividing into two, at a, by constriction of the primordial utricle. FIG. 21. A portion of the same at a, more magnified, showing the formation of the par- tition. 22. Same, with the partition completed.CIRCULATION IX CELLS. 31' indefinitely from one end, by a sort of gemmation or budding growth, while all the rest remains stationary, or while the opposite extremity is dead or decaying. Fig. 20 would represent a case of the kind, except that partitions form, as the upper end grows on, dividing the tube into a row of cylindrical cells. Sometimes a new point of growth commences on the side of a cell, so giving rise to 38. Branching Cells. The hair- like bodies that copiously appear on the surface of young rootlets furnish examples of the kind, as is shown in Fig. 1, 23, 24. More conspicuous examples are furnish- ed by certain Alga; of the simplest structure, where the cell branches profusely as it elongates, but the tubes are all perfectly continu- ous throughout; as in Botrydium (Fig. 88), where an originally spherical cell is extended and ramified below in the fashion of a root; in Yaucheria (Fig. 89), where a slender tube forks or branches sparingly; and in Bryopsis (Fig. 91), where numerous branches are symmetrically arranged in two opposite rows, like the plume of a feather. In these cases, the fully developed plant, with all its branches, is only one proliferous cell, extended from various points by this faculty of continuous bud- ding growth. The mycelium or spawn of Mushrooms, and the in- tricate threads of Moulds (Fig. 92 - 94) are formed of very attenuated branching cells. And in Lichens and many Fungi, cells of this kind are densely interwoven into a filamentous tissue (Fig. 25). 39. Cyclosis or Circulation in Cells. In all young cells, probably, at least at some period, the fluid protoplasm interposed between the cell-walls and the watery sap is in a state of movement. Under FIG. 23 Magnified cellular tissue from the rootlet of a seedling Maple ; some of the ex- ternal cells growing out into root-hairs. 24 A few of the cells more highly magnified. FIG 25. Entangled, filamentous, branching cells from the fibrous tissue of the Reindeer Lichen (Cladonia rangiferina), magnified.32 THE ELEMENTARY STRUCTURE OF PLANTS. u tJL $?<$•), which gives to the twigs of trees and shrubs the hue peculiar to each spe- cies, generally some shade of ash-color or brown, or occasionally of much more vivid tints. It is this tissue, which, taking an unusual development, forms the cork of the Cork-Oak, and those corky ex- pansions of the bark which are so conspicuous on the branches of B c w I VI-----1 /-------------------------------v FIG. 194. Portion of a transverse section, and 195, a corresponding vertical section, magni- fied, reaching from the pith, p, to the epidermis, e, of a stem of Negundo, a year old : B, the bark ; TF, the wood ; and C, the cambium-layer, as found in February. The references are in the text above ; except mr, portion of a medullary ray, seen on the vertical section, where it runs into the pith : dd, dotted ducts : cZ, the inner part of the cambium-layer, which begins the new layer of wood. In this tree, we find a thick layer of parenchyma (Z) inside of the bast- tissue, and therefore belonging to the liber. No bast-tissue is formed in it the second year. 11122 THE STEM. the Sweet Gum (Liquidambar), and on some of our Elms (Ulmus alata and racemosa). It also forms the paper-like, exfoliating layers of Birch-bark. It is composed of laterally flattened parenchymatous cells, much like those of the Epidermis (69, Fig. 191, i), which directly overlies it, and forms the skin or surface of the stem. 218. The elements of an exogenous stem of a year old, especially in a woody plant, accordingly are these, proceeding from the centre towards the circumference : — I. In the Wood: 1. The Pith, belonging to the cellular system (Fig. 194, 195, p). 2. The Medullary Sheath, ms, ) which belong to the woody or 3. The Layer of Wood, W, w, ) longitudinal system. 4. The Medullary Rays, mr, a part of the cellular system. II. In the Bark : 5. The Liber, l; its bast-tissue, b, belongs to the woody system. 6. Tlie Outer Baric, belonging wholly to the cellular system, and composed of two parts, viz.: 1st, the Green or Cellular En- velope, ye, and 2d, the Corley Envelope, ce. 7. The Epidermis, e, or skin, which invests the whole. 219. An herbaceous stem does not essentially differ from a woody one of this age, except that the wood forms a less compact or thinner zone ; and the whole perishes, at least down to the ground, at the close of the season. But a woody stem makes provision for contin- uing its growth the second year. As the layer of wood continues to increase in thickness throughout the season, by the multiplication of cells on its outer surface, between it and the bark, and when growth ceases this process of ccdl-multiplication is merely suspended, so there is always a zone of delicate young cells interposed between the wood and the bark. This is called the 220. Cambium-Layer, (Fig. 194, 195, C). It is charged with or- ganizable matter (protoplasm, dextrine, &c.) in the form of a mu- cilage, which is particularly abundant in the spring when growth recommences. This mucilaginous matter was named Cambium by the older botanists; who supposed — as is still generally thought — that the bark, then so readily separable, really separated from the wood in spring, that a quantity of rich mucilaginous sap was poured out between them, and that this sap, or cambium, was organized into a tissue, the inner part becoming new wood, the outer, new bark. But delicate slices will show that there is then no more inter- ruption of the wood and inner bark than at any other season; thatEXOGENOUS STRUCTURE. 123 the two are always organically connected by an extremely delicate tissue of young and vitally active cells, just in the state in which they multiply by division (33). The bark, indeed, is very readily detached from the wood in spring, because the cambium-layer is then gorged with sap; but the separation is effected by the rending of a delicate forming tissue. And if some of this apparant mucilage be scraped off from the surface of the wood, and examined under a good microscope, it will be seen to be a thin stratum of young wood-cells, with the ends of medullary rays here and there interspersed, and appearing much as in Fig. 193, only the young wood-cells are mostly shorter. The inner portion of the iambium-layer is therefore nas- cent wood, and the outer is nascent bark. And it is by the growth of the cambium-layer, renewed year after year, that the 221. Annual Increase of the Wood of Exogenous plants is effected: As the cells of this layer multiply, the greater number lengthen ver- tically into prosenchyma or woody tissue ; while some are trans- formed into ducts, and others, remaining as parenchyma, continue the medullary rays or commence new ones. In this way a second layer of wood is formed the second season, over the whole surface of the former layer and between it and the bark, and continuous with the woody layer of the new roots below and of the leafy shoots of the season above. Each succeeding year another layer is added to the wood in the same manner, coincident with the growth in length by the development of the buds. A cross-section of an exogenous stem, therefore, exhibits the wood disposed in concentric rings between the bark and the. pith ; the oldest lying next the latter, and the youngest occupying the circumference. Each layer being the pro- duct of a single year’s growth, the age of an exogenous tree may, in general, be correctly ascertained by counting the rings in a cross- section of the trunk.* * The annual layers are most distinct in trees of temperate climates like ours, where there is a prolonged period of total repose, from the winter’s cold, fol- lowed by a vigorous resumption of vegetation in spring. In tropical trees they are rarely so well defined; but even in these there is generally a more or less marked annual suspension of vegetation, occurring, however, in the dry and hotter, rather than in the cooler season. There are numerous cases, moreover, in which the wood forms a uniform stratum, whatever be the age of the trunk, as in the arborescent species of Cactus ; or where the layers are few and by no means corresponding with the age of the trunk, as in the Cycas. In many woody climbing or twining stems, such as those of Clematis, Aristo-124 THE STEM. 222. The Limitation of the Annual Layers results from two or more causes, separate or combined. In oak and chestnut wood, and the like, the la)rers are strongly defined by reason of the accumulation of the large dotted ducts, here of extreme size and in great abundance, in the inner portion of each layer, where their open mouths on the cross-section are conspicuous to the naked eye, making a strong con- trast between the inner porous, and the exterior solid part of the successive layers. In Maple and Beech wood, however, the ducts are smaller, and are dispersed throughout the whole breadth of the layer; and in coniferous wood, viz. that of Pine, Cypress, &c., there are no ducts at all, but only a uniform woody tissue of a peculiar sort (4G, 54). Here the demarcation between two layers is owing to the greater fineness of the wood-cells formed at the close of the season, viz. those at the outer border of the layer, while the next layer begins, in its vigorous vernal growth, with much larger cells, thus marking an abrupt transition from one layer to the next. Be- sides being finer, the last wood-cells of the season are often flattened laterally, more or less. 223. Each layer of wood, once formed, remains unchanged in posi- tion and dimensions. But in trunks of considerable age, the older layers generally undergo more or less change in color and density, distinguishing the wood into two parts, viz. 224. Sap-W00(l and Heart-wood. In the germinating plantlet and in the developing bud, the sap ascends through the whole tissue, of whatever sort; at first through the parenchyma, for there is then no other tissue ; and the transmission is continued through it, especially through its central portion, or the pith, in the growing apex of the stem throughout. But in the older parts below, the pith, soon drained of sap, becomes filled with air in its place, and thenceforth it bears no part in the plant’s nourishment. As soon as wood-cells and ducts are formed, they take an active part in the conveyance of sap ; lochia Sipho, and Menispermum Canadense, the annual layers are rather obscure- ly marked, while the medullary rays are unusually broad; and the wood therefore forms a series of separable wedges disposed in a circle around the pith. In the stem of one of our Trumpet-creepers (the Bignonia capreolata) the annual rings, after the first four or five, are interrupted in four places, and here as many broad plates of cellular tissue, belonging properly to the bark, are interposed, passing at right angles to each other from the circumference towards the centre, so that the transverse section of the wood nearly resembles a Maltese cross. But these are all exceptional cases, which scarcely require notice in a general view.SAP-WOOD AND HEAKT-WOOD. 125 for which their tubular and capillary character is especially adapted. But the ducts in older parts, except when gorged with sap, contain air alone ; and in woody trunks the sap continues to rise year after year, to the places where growth is going on, mainly through the proper woody tissue of the wood. In this transmission the new layers are most active, and these are in direct communication with the new roots on the one hand and with the buds or shoots and leaves of the season on the other. So, by the formation of new annual layers out- side of them, the older ones are each year removed a step farther from the region of growth; or rather the growing stratum, which connects the fresh rootlets that imbibe with the foliage that elabo- rates the sap, is each year removed farther from them. The latter, therefore, after a few years, cease to convey sap, as they have long FIG. 196. Magnified cross-section of a portion of woody tissue of White Oak, a year old. 197. A longitudinal as well as cross section of the same, a little higher magnified, a, a, Por* tions of one of the smaller medullary rays. FIG. 198. Magnified cross-section of woody tissue from the same stem, taken from a layer of heart-wood, 24 years old: 6, ducts : a, portion of one of the minuter medullary rays. 199. Combined cross and longitudinal section of the same: a, tissue of a medullary ray. II Vi126 THE STEM. before ceased to take part in any vital operations. The cells of the older layers, also, commonly have thicker walls and smaller calibre than those of the newer, — as here shown in Fig. 198,199, compared with Fig. 196, 197, — owing to the greater amount of thickening or- ganic materials (43) mingled with encrusting mineral matters intro- duced with the water imbibed by the roots (93) which have 'been de- posited upon them from within. This older, more solidified, and harder wood, which occupies the centre of the trunk, and is the part princi- pally valuable for timber, &c., is called Heart-wood, or Duramen : while the newer layers of softer, more open, and bibulous wood, more or less charged with sap, receive the name of Sap-wood, or Albur- num. The latter name was given by the earlier physiologists in allu- sion to its white or pale color. In all trees which have the distinction between the sap-wood and heart-wood well marked, the latter acquires a deeper color, and that peculiar to the species, such as the dark brown of the Black Walnut, the blacker color of the Ebony, the purplish-red of Bed Cedar, and the bright yellow of the Barberry. These colors arc owing to special vegetable products mixed with the inerusting matters ; but sometimes the hue appers to be rather an alteration of the lignine with age. In the Bed Cedar, the deep color belongs chiefly to the medullary rays. In many of the softer woods, there is little thickening of the cell-walls, and little change in color of the heart-wood, except from incipient decay, as in the White Pine, Pop- lar, Tulip-tree, &c. The heart-wood is no longer in any sense a 1 living part; it may perish, as it frequently does, without affecting the life or health of the tree. 225. The Bark is much more various in structure and growth than the wood: it is also subject to grave alterations with advancing age, on account of its external position, viz. to distention from the con- stantly increasing diameter of the stem within, and to abrasion and decay from the influence of the elements without. It is never entire, therefore, on the trunks of large trees ; but the dead exterior parts, no longer able to enlarge with the enlarging wood, are gradually fissured and torn, and crack off in layers, or fall away by slow decay. So that the bark of old trunks bears but a small proportion in thick- ness to the wood, even when it makes an equal amount of annual growth. 226. The three parts of the bark (214-217), for the most part readily distinguishable in the bark of young shoots, grow indepen- dently, each by the addition of new cells to its inner face, so long asTHE BARK. 127 » it grows at all. The green layer does not increase at all after the first year ; the opaque corky layer soon excludes it from the light; and it gradually perishes, never to be renewed. The corky layer commonly increases for a few years only, by the formation of new tabular cells : occasionally it takes a remarkable development, form- ing the substance called Cork, as in the Cork Oak. A similar growth occurs on the bark of several species of Elm, of our Liquid- ambar or Sweet-Gum, &c., pro- ducing thick corky plates on the branches. In the White and Pa- per Birch, thin layers, of a very durable nature, are formed for a great number of years ; each layer of tabular and firmly cohe- rent cells (Fig. 200, a) alternates with a thinner stratum of delicate, somewhat cubical and less compact cells (b), which break up into a fine powder when disturbed, and allow the thin, paper-like plates to exfoliate. 227. The liber, or inner bark (215), continues to grow through- out the life of the tree, by an annual addition from the cambium- layer applied to its inner surface. Sometimes the growth is plainly distinguishable into layers, corresponding with or more numerous than the annual layers of the wood: often, there is scarcely any trace of such layers to be discerned. In composition and appearance the liber varies greatly in different plants,* especially in trees and shrubs. That of Bass-wood or Linden, and of other plants with a similar fibrous bark, may be taken as best representing the liber. Here it consists of strata of very thick-walled cells alternating with thin-walled cells. The thick-walled cells are bast-cells (55, Fig. 49, 53), are much elongated vertically, and form the fibrous portion of * The best account of the liber that has yet been given is that by Mohl, in the Botanische Zeitunrj, Vol. 13, p 873 (1855), of which a French translation is published in the Annales des Sciences Naturelles, ser. 4, Yol. 5, p. 141, et scq. (1856). FIG 200. Transverse section of a minute portion of White Birch bark, the corky layer highly magnified : a, the firm, tabular cells, 6, delicate thin-walled cells which separate the papery plates. (After link.)128 THE STEM. the bark. The thin-walled cells are those of ordinary parenchyma, mingled, at the inner part of each stratum, with larger and longer ones, marked (on some sides at least) with the thin and reticulated spots or punctuations already described (215). These last may be termed the proper cells of the liber, as they are peculiar to this part 'of the bark, are seldom if ever absent, they contain an abundance of mucilage and proteine, and in all probability they take the principal part in the descending circulation of the plant, if it may so be called, _i. e. in conveying downwards and distributing the rich sap which has been elaborated in the foliage. It is evident that the bast-cells, which in Linden (Fig. 53) are seen to be almost solid, are not adapted to this purpose. 228. That bast-cells are not an essential part, is further evident -tfrom the fact, that they are altogether wanting in the bark of some ' plants, and are not produced after the first year in many others. The latter is the case in Negundo, where abundant bast-cells, like those of Bass-wood, compose the exterior portion of the first year’s liber (Fig. 194, 195, b), but none whatever is formed in the subsequent layers. In Beeches and Birches, also, a few bast-cells are produced the first year, but none afterwards. In Maples a few are formed in succeeding years. In the Pear bast-cells are annually formed, but in very small quantity, compared with the parenchymatous part of the liber. In Pines, at least in White Pines, the bark is nearly as homogeneous as the wood, the whole liber, except what answers to the medullary rays, consisting of one kind of cells, resembling those of bast or of wood in form, but agree- ing with the proper liber-cells in their structure and markings. Although the liber of Birch produces no bast- cells after the first year, it abounds in short cells equally solidified by in- ternal deposition, and of a gritty tex- ture, which might be mistaken for bast-cells on the cross-section (Fig. 201). A longitudinal section discloses the difference. 220. The bark on old stems is constantly decaying or falling away from the surface, without any injury to the tree ; just as the heart- wood may equally decay within without harm, except by mechani- FIG. 201. Cross-section of a cluster of solidified and indurated cells from the liber of tho White Birch. (After Link )THE LIVING PARTS OP A TREE. 129 nermost layers are alive the stems of the commc cally impairing the strength'of the trunk. Great differences are observable as to the tiipe and manner in which the older bark of different shrubs and trees is thrown off, according to the struc- ture in each species. Some trees and shrubs have their trunks in- vested with the liber of j many years’ growth, although only the in- in others it scales off much earlier. On n Honeysuckle, of the Nine-Bark (Spiraea opulifolia), and of Grape-vines (except of our Muscadine Grape), the liber lives only one season, and i;i detached the following year, hanging loose in papery layers in the former species, and in fibrous shreds in the latter. 230. While the newer=Tayers oT'thr w6od abound in crude sap, which they convey to the leaves (224), those of the inner bark abound in elaborated sap (79, 227), which they receive from the leaves and convey to the cambium-layer or zone of growth. The/ proper juices and peculiar products of plants (88) are accordingly, found in the foliage and the bark, especially in the latter. In the bark, therefore, (either of the stem or of the root,) medicinal and other principles are usually to be sought, rather than in the wood. Nevertheless, as the wood is kept in connection with the bark by the medullary rays, many products which probably originate in the former are deposited in the wood. 231. The Living Parts of a Tree or Shrub, of the Exogenous kind, are obviously only these: — 1st. The summit of the stem and branches, with- the buds which continue them upwards and annually develop the foliage. 2d. The fresh tips of the roots and rootlets annually developed at the opposite extremity. 3d. The newest strata of wood and bark, and especially the interposed cambium-layer, which, annu- ally renewed, maintain a living communication between the rootlets on the one hand and the buds and foliage on the other, however dis- tant they at length may be. These are all that is concerned in the life and growth of the tree ; and these are annually renewed. The branches of each year’s growth are, therefore, kept in fresh commu- nication, by means of the newer layers of wood, with the fresh rootlets, which are alone active in absorbing the crude food of the plant from the soil. The fluid they absorb is thus conveyed directly to the branches of the season, which alone develop leaves to digest it. And the sap they receive, having been elaborated and converted into organic nourishing matter, is partly expended in the upward growth of new branches, and partly in the formation of a new layer130 THE STEM. of wood, reaching from the highest leaves to the remotest rootlets.* As the exogenous tree, therefore, annually renews its buds and * The layers of wood and bark, by which the exogenous stem annually in- creases in diameter, are formed by the multiplication of the cells of the cambium- layer throughout its whole extent. That the organic material to supply this growth in ordinary vegetation descends in the bark, for the most part, and that the order of growth in the formation of wood is from above downwards, and also the general dependence of this growth upon the action of the foliage, may be inferred from a variety of facts and considerations. The connection of the wood with the leaves is shown : — (1.) By tracing the threads of soft woody Endogcns, such as Yucca, directly from the base of the leaf into the stem, and thence downward to their termination, towards which they become attenuated, lose their vessels, and are finally reduced to slender shreds of woody tissue. (2.) The amount of wood formed in a stem or branch, other things being equal, is in a relation to the number and size of the leaves it bears; its amount in any portion of the branch is in direct proportion to the number of leaves above that portion. Thus, when the leaves are distributed along a branch, it tapers to the summit, as in a common Reed or a stalk of Indian Coni; when they grow in a cluster at the apex, it remains cylindrical, as in a Palm (Fig. 184). Consequently the increase of the trunk in diameter directly eoiTesponds with the number and vigor of the branches. The greater the development of vigorous branches on a particular side of a tree, the more wood is formed, and the greater the thickness of the annual layers on that side of the trunk. (3.) In u seedling, the wood appears in proportion as the leaves are developed.. (4.) If a young branch be cut off just below a node (156), so as to leave an internode without leaves or bud, little or no increase in diameter will ordinarily take place down to the first leaf below. But if a bud be inserted into this naked internode, as the bud de- velops, increase in diameter, with the formation of new wood, recommences. That the formation proceeds from above downwards, or that the elaborated sap which furnishes the material for the growth is diffused from above downwards, appears from the effect of a ligature around exogenous stems, or of removing a ring of bark. It is a familiar fact, that, when a ligature is closely bound around a growing exogenous stem, the part above the ligature swells, and that below docs not. Every one may have observed the distortions that twining stems thus accidentally produce upon woody exogenous trunks, causing an enlargement on the upper side of the obstruction. When the stem is girdled, by removing a ring of bark so as completely to expose the surface of the wood, the part above the ring enlarges in the same manner; that below does not, until the incision is healed. The wood of the roots is manifestly formed in a descending direction. But this is continuous with that of the stem; and its first layer, the extension of the wood of the radicle into the primary root, agrees in composition with the wood of the succeeding layers in the stem, having no spiral vessels, but only ducts. Still, whatever analogy there may be between the growth of the wood in the stem and of roots, there is no real basis for the ingenious conception of Thouars and of Gaudichaud, that wood is the roots of buds or leaves, or that it is absolutely dependent upon them for its formation.COMPOSITE NATURE OP A PLANT. 131 leaves, its wood, bark, and roots, — everything, indeed, that is con- cerned in its life and growth, — there seems to be no reason, no necessary cause inherent in the tree itself, why it may not live in- definitely. Accordingly, some trees art; known to have lived for twelve hundred years or more ; and others now survive which are probably above two thousand years old, and perhaps much older.* This longevity ceases to be at all surprising when we consider, that, although the tree or herb is in a certain sense an individual, yet it is not an individual in the sense that a man or any ordinary animal is. Viewed philosophically, 232. The Plant is a Composite Being, or community, lasting, in the case of a tree especially, through an indefinite and often immense number of generations. These are successively produced, enjoy a term of existence, and perish in their turn. Life passes onward continually from the older to the newer parts, and death follows, with equal step, at a narrow interval. No portion of the tree is now living that was alive a few years ago ; the leaves die annually and are cast off, while the internodes or joints of stem that bore them, as to their wood at least, buried deep in the trunk, under the wood of succeeding generations, are converted into lifeless heart-wood, or perchance decayed, while the bark that belonged to them is thrown off from the surface. It is the aggregate, the blended mass alone, that long survives. Plants of single cells, and of a definite form, alone exhibit complete individuality; and their existence is ex- tremely brief. The more complex vegetable of a higher grade is not to bo compared with the animal of the highest organization, where the offspring always separates from the parent, and the indi- vidual is simple and indivisible. But it is truly similar to the branch- ing or arborescent coral, or to other compound animals of the lowest grade, where successive generations, though capable of living inde- pendently and sometimes separating spontaneously, yet are usually developed in connection, blended in a general body, and nourished more or less in common. Thus the coral structure is built up by the combined labors of a vast number of individuals, — by the suc- * The subject of the longevity of trees has been ably discussed by De Can- dolle, in the Bibliolheque Universelle of Geneva, for May, 1831, and in the second volume of his Physiologie Vfye'tale: also, more recently, by Professor Alphonse De Candolle. In this country, an article on the subject has appeared in the North American Review, for July, 1844.132 THE STEM. cessive labors of a great number of generations. The surface or the recent shoots alone are alive ; and here life is superficial, all under- neath consisting of the dead remains of^ former generations. The arborescent species are not only lifeless along the central axis, but are dead throughout towards the bottom : as, in a genealogical tree, only the later ramifications are among the living. It is the same with the vegetable, except that, as it ordinarily imbibes its nourish- ment mainly from the soil through its roots, it makes a downward growth also, and, by constant renewal of fresh tissues, maintains the communication between the two growing extremities, the buds and the rootlets. 233. Individuality being imperfectly realized in the vegetable kingdom, the question as to what in the Phmnogamous plant best answers to the animal individual is speculative, rather than practical, and may be more appropriately noticed in another place. (Part II. Chap. I.) 234. Comparison of Endogenous with Exogenous Structure. The woody bundles of an exogenous stem (Fig. 18G-188) continue to grow on the outer side as long as the plant lives. In woody trunks they at once become wedges with the point next the pith, and growth pro- ceeds indefinitely by the stratum of perpetually renewed tissue on the outer face between the wood and the bark. Each wedge is separated from its neighbor on both sides by an interposed medul- lary ray, and is composed of wood on the inner side, liber on the outer, and cambium or forming tissue between. Now each thread or bundle of endogenous wood (204) is composed of similar or anal- ogous parts, sometimes irregularly intermixed, but more commonly similarly disposed. That is, the section of one of these threads ex- hibits woody tissue and one or two spiral vessels on its inner border, answering to the proper wood, and very thick-walled elongated cells on its outer border, of the same nature as the bast-cells of Exogens ; and between the two is a stratum of cells of parenchyma mixed with elongated and punctuated cells answering to the proper cells of the inner part of the liber. The portion of each endogenous thread, therefore, which looks towards the centre of the trunk, answers to the wood, and its outer portion to the liber or inner bark, of the ex- ogenous stem; and the parenchyma through which the threads are interspersed answers to the medullary rays and pith together. The main difference between the endogenous woody threads and the ex- ogenous woody wedges is, that there is no cambium-layer in theTHE LEAVES. 133 former between the liber and the wood, and therefore no provision for increase in diameter. The bundles are therefore strictly limited, while those of Exogens are unlimited in growth. In Exogens the woody bundles or wedges, symmetrically arranged in a circle, be- come confluent into a zone in all woody and most herbaceous stems, which continues to increase in thickness. In Endogens the woody bundles are unchanged in size after their formation, but new and distinct ones are formed in the growing stem with each leaf it de- velops, and interspersed more or less irregularly among the older bundles. CHAPTER Y. OP THE LEAVES. Sect. I. Their Arrangement. (Phyllotaxis, etc.) 235. The situation of leaves, as well as their general office in the vegetable economy, and several of their special adaptations, has already been stated. Leaves invariably arise from the nodes (156), just below the point where buds appear. So that wherever a bud or branch is found, a leaf exists, or has existed, either in a perfect or rudimentary state, just beneath it; and buds (and therefore branch- es), on the other hand, are or may be developed in the axils of all leaves, and do not normally exist in any other situation. The point of attachment of a leaf (or other organ) with the stem is termed its insertion. The subject of the arrangement of leaves on the stem has received the name of 236. Phyllotaxis (from two Greek words, signifying leaf-arrange- ment). 237. As to their general position, leaves are either alternate, oppo- site, or verticillate. They are said to be alternate (127, and Fig. 121, 157, 204) when there is only one to each node, in which case the successive leaves are thrown alternately to different sides of the stem. They are said to be opposite when each node bears a pair of leaves, in which case the two leaves always diverge from each other as widely as possible, that is, they stand on opposite 12134 THE LEAVES. sides of the stem and point in opposite directions (127, Fig. 107, 210, &c.). They are verticillate, or whorled, when there are three or more leaves in a circle (I'erticil or whorl) upon each node ; in which case the several leaves of the circle diverge from each other as much as possible, or are equably distributed around the whole circumfer- ence of the axis (Fig. 134, 211). The first of the three is the simplest as well as the commonest method, occurring as it does in almost every Monocotyledonous plant (where it is plainly the normal mode, 128), and in the larger number of Dicotyledonous plants likewise, after the first or second nodes (Fig. Ill*, 121). It should therefore be first examined. 238. Alternate Leaves. This general term for the case where leaves are placed one after another, obviously comprises a variety of modes as to the particular position of succes- sive leaves. There is, first, the case to which the name is most applicable, viz. where the leaves are alternately disposed on exactly op- posite sides of the stem (as in Fig. 157) ; the second leaf being on the side farthest from the first, while the third is equally distant from the second, and is consequently placed directly over the first, the fourth stands over the second, and so on throughout. Such leaves are accordingly distichous or two-ranked.* They form two vertical rows : on one side are the 1st, 3d, 5th, 7th, &c.; on the op- posite side are the 2d, 4th, 6th, 8th, and so on. This mode occurs in all Grasses, in many other Monocotyledonous plants, and among the Dicotyledonous in the Linden. A second mode is 239. The tristichous or three-ranked ar- rangement, which is seen in Sedges (Fig. * In the course of the summer the leaves of Baptisia perfoliata, which are really five-ranked, often appear to be monostichous, or one-ranlced; hut this is owing to a torsion of the axis. FIG. 202. Piece of a Btalk, with the sheathing bases of the leaves, of a Sedge-Grass (Carex Crus-corvi), showing the three-ranked arrangement. 203. Diagram of the cross-section of the same, showing two cycles of leaves. *THEIR ARRANGEMENT. 135 202) and some other Monocotyledonous plants. Taking any leaf we please to begin with, and numbering it 1, we pass round one third of the circumference of the stem as we ascend to leaf No. 2 ; another third of the circumference brings us to No. 3 ; another brings us round to a point exactly over No 1, and here No. 4 is placed. No. 5 is in like manner over No. 2, and so on. They stand, therefore, in three vertical rows, one of which contains the numbers 1, 4, 7, 10; another, 2, 5, 8, 11 ; the third, 3, 6, 9, 12, and so on. If we draw a line from the insertion of one leaf to that of the next, and so on to the third, fourth, and the rest in succession, it will be perceived that it winds around the stem spirally as it ascends. In the first or dis- tichous mode, the second leaf is separated from the preceding by half the circumference of the stem; and, having completed one turn round the stem, the third begins a second turn. In the tristichousj> each leaf is separated from the preceding and succeeding by one third of the circumference, there are three leaves in one turn, or cycle, and the fourth commences a second cycle, which goes on in the same way. That is, the angular divergence, or arc interposed between the insertion of two successive leaves, in the first is i, in the second of the circle. These fractions severally represent, not only the angle of divergence, but the whole plan of these two modes; the numerator denoting the number of times the spiral line winds round the stem before it brings a leaf directly over the one it began with; while the denominator expresses the number of leaves that are laid down in this course, or which form each cycle. The two- ranked mode (i) is evidently the simplest possible case. The three- ranked (j) is the next, and the one in which the spiral character of the arrangement begins to be evident. To this succeeds 240. The pentastichous, quincuncial, or five-ranked arrangement (Fig. 204, 205). This is much the most common case in alternate- leaved Dicotyledonous plants. The Apple, Cherry, and Poplar afford ready examples of it. Here there are five leaves in each cycle, since we must pass on to the sixth before we find one placed vertically over the first. To reach this, the ascending spiral line has made two revolutions round the stem, and on it the five leaves are equably distributed, at intervals of § of the circumference. The fraction § accordingly expresses the angular divergence of the suc- cessive leaves ; the numerator indicates the number of turns made in completing the cycle, and the denominator gives the number of leaves in the cycle, or the number of vertical ranks of leaves on such136 THE LEAVES. a stem. If we shorten the axis, as it was in the bud, or make a horizontal plan, we have aos the parts disposed as in the diagram, Fig. 206, the low- er leaves being of course the exterior. 241. The eight-ranked arrangement, the next in order, is likewise not un- common. It is found in the Holly, the Callistemon of our conservatories, the Aconite, the tuft of leaves at the base of the common Plantain, &c. In this case the ninth leaf is placed over the first, the tenth over the second, and so on ; and the spiral line makes three turns in laying down the cycle of eight leaves, each separated from the preceding by an arc, or an- gular divergence, of f of the circumference. 242. All these modes, or nearly all of them, were pointed out by Bonnet as long ago as the middle of the last century ; but they have recently been extended and generalized, and the mutual relations of the various methods brought to light, by Sehimper, Braun, and others. If we write down in order the series of fractions which represent the simpler forms of pliyllotaxis already noticed, as determined by observation, viz. we can hardly fail to perceive the relation that they bear to each other. For the numerator of each is composed of the sum of the numerators of the two preceding fractions, and the denominator of the sum of the two preceding denominators. Also the numerator of each fraction is the denominator of the next but one preceding. Extending this series, we obtain the further terms, Tsj, ?ST, §■£, &c. Now these numbers are verified by observation, and, with some abnormal excep- tions, this series £, J, f, $■, ^ /T, f 1, comprises all the varia- FIG. 204. A branch exhibiting the five-ranked arrangement of leaves. FIG. 205. Diagram of the same: a spiral line is drawn ascending the stem and passing through the successive scars which mark the position of the leaves from 1 to 6. It is made a dotted line where it passes on the opposite side of the stem, and the scars 2 and 5, which fall on that side, are made fainter. 206. A plane, horizontal projection of the same ; the dotted line passing from the edge of the first leaf to the second, and so on to the fifth leaf, which completes the cycle ; as the sixth would come directly before, or within, the first.THEIR ARRANGEMENT. 137 tions of the arrangement of alternate leaves that actually occur. These higher forms are the most common where the leaves are crowded on the stem, as in the rosettes of the Houseleek (Fig 207), and the scales of the Pine-cones (for the ar- rangement extends to all parts that are modifi- cations of leaves), or where they are numerous and small in proportion to the circumference of the stem, as the leaves of Firs, &c. In fact, when the internodes are long and the base of the leaves large in proportion to the size of the stem, it is difficult, and often impossible, to tell whether the 9th, 14th, or 22d leaf stands ex- actly over the first. And when the intemodes are very short, so that the leaves touch one another, or nearly so, we may readily per- ceive what leaves are superposed ; but it is then difficult to follow the succession of the intermediate leaves. The order, however, may be deduced by simple processes. 243. Sometimes we can readily count the number of vertical ranks, which gives the denominator of the fraction sought. Thus, if there are eight, we refer the case to the § arrangement in the regu- lar series ; if there are thirteen, to the TaT arrangement, and so on. Commonly, however, when the leaves are crowded, the vertical ranks are by no means so manifest as two or more orders of oblique series, or secondary spirals, which are at once seen to wind round the axis in opposite directions, as in the Houseleek (Fig. 207 ; where the numbers, 1, 6, 11 belong to a spire that winds to the left; 1, 9, 17 to another, which winds to the right; and 3, 6, 9, 12 to still another, that winds in the same direction) : they are still more ob- vious in Pine-cones (Fig. 208, 209). These oblique spiral ranks are a necessary consequence of the regular ascending arrangement of parts with equal intervals over the circumference of the axis : and if the leaves are numbered consecutively, these numbers will neces- sarily stand in arithmetical progression on the oblique ranks, and have certain obvious relations with the primary spiral which origi- nates them ; as will be seen by projecting them on a vertical plane. 244. Take, for example, the quincunical (§) arrangement, where, as in the annexed diagram, the ascending spiral, as written on a plane surface, appears in the numbers 1, 2, 3, 4, 5, 6, and so on: FIG. 207. An offset of the Houseleek, with the rosette of leaves unexpanded, exhibiting the 5-13 arrangement; the fourteenth leaf being directly over the first. 12*138 THE LEAVES. the vertical ranks thus formed, beginning with the lowest (which we place in the middle column, that it may correspond with the Larch-cone, Fig. 208, where the lowest scale, 1, is turned directly towards the observer), are neces- sarily the numbers 1, 6, 11 ; 4, 9, 14 ; 2, 7, 12; 5, 10, 15; and 3, 8, 13. But two parallel oblique ranks are equally apparent, ascending to the left; viz. 1, 3, 5, which, if we coil the diagram round a cylinder, will be continued into 7, 9, 11, 13, 15 ; and also 2, 4, 6, 8,10, which runs into 12,14, and so on, if the axis be further prolonged. Here the circumference is occupied by two secondary left-hand series, and we notice that the common difference in the sequence of numbers is two: that is, the number of the parallel sec- ondary spirals is the same as the common difference of the numbers on the leaves that compose them. Again, there are other parallel secondary spiral ranks, three in number, which ascend to the right; viz. 1, 4, 7, continued into 10, 13 ; 3, 6, 9, 12, continued into 15 ; and 5, 8, 11,14, &e.; where again the common difference, 3, accords with the number of such ranks. This fixed relation enables us to lay down the proper numbers on the leaves, when too crowded for directly following their succession, and thus to ascertain the order of the primary spiral series by noticing what numbers come to be super- posed in the vertical ranks. We take, for example, the very simple cone of the small-fruited'American Larch (Fig. 208), which usually completes only two cycles ; for we see that the lowest, one interme- diate, and the highest scale, on the side towards the observer, stand in a vertical row. Marking this lowest scale 1, and counting the parallel secondary spirals that wind to the left, we find that two occupy the whole circumference. From 1, we number on the scales of that spiral 3, 5, 7, and so on, adding the common difference 2, at each step. Again, counting from the base the right-hand secondary spirals, we find three of them, and therefore proceed to number the lowest one by adding this common difference, viz. 1,4,7,10; then, pass- ing to the next, on which the No. 3 has already been fixed, we carry on that sequence, 6, 9, &c.; and on the third, where No. 5 is already fixed, we continue the numbering, 8, 11, &c. This gives us, in the vertical rank to which No. 1 belongs, the sequence 1, 6, 11, showing FIG. 208. A cone of the small-fruited American Larch (Larix Americana), with the scales numbered, exhibiting the five-ranked arrangement, as in the annexed diagram.THEIR ARRANGEMENT. 139 that the arrangement is of the quineuncial (|) order. It is further noticeable, that the smaller number of parallel secondary spirals, 2, agrees with the numerator of the fraction in this the § arrangement; and that this number added to that of the parallel secondary spirals which wind in the opposite direction, yiz. 3, gives the denominator of the fraction. Tins holds good throughout; so that we have only to count the number of parallel secondary spirals in the two direc- tions, and assume the smaller number as the numerator, and the sum l of this and the larger number as the denominator, of the fraction which expresses the angular divergence sought. For this we must FIG 209. A con© of the White Pine, on which the numbers are laid down, and the leading higher secondary spirals are indicated: those with the common difference 8 are marked by dotted line3 ascending to the right; two of the five that wind in the opposite direction are also marked with dotted line^ : the set with the common difference 3, in one direction, and that with the common difference 2^ in the other, are very manifest in the cone.140 THE LEAVES. take, however, the order of secondary spirals nearest the vertical rank in each direction, when there are more than two, as there are in all the succeeding cases. 245. A similar diagram of the f arrangement introduces a set of secondary spirals, in addition to the two foregoing, ascending in a near- er approach to a vertical line, and with a higher common difference, viz. 5. There are accordingly five of this sort, viz. those indicated in the diagram by the series 1, 6, 11, 16 ; 4, 9, 14, 19, 24; 2, 7, 12, 17, 22 ; 5,10,15, 20, 25 ; and 3, 8,13,18, 23. The highest obvious spiral in the opposite direction, viz. that of which the series 1, 4, 7, 10, 13 is a specimen, has the common difference 3, and gives the numerator, and 3 -)- 5 the denominator, of the fraction §. The next case, Tj, which is exemplified in the rosettes of the Houseleek (Fig. 207) and in the cone of the White Pine (Fig. 209), introduces a fourth set of secondary spirals, eight in number, with the common difference eight, viz. that of which the series 1, 9, 17, 25 is a repre- sentative. The set that answers to this in the opposite direction, viz. 1, 6, 11, 16, 21, 26, with the common difference 5, gives the numerator, and 5 —)— 8 the denominator, of the fraction We may here compare the diagram with an actual example (Fig. 209) : a part of the numbers are of course out of sight on the other side of the cone. The same laws equally apply to the still higher modes. 246. The order is uniform in the same species, but often various in allied species. Thus, it is only § in our common American Larch; in the European species, /r. The White Pine is ytj, as is also the Black Spruce ; but other Pines with thicker cones exhibit in differ- ent species the fractions Jr, and | j. Sometimes the primitive spiral ascends from left to right, sometimes from right to left. One direction or the other generally prevails in each species, yet both directions are not unfrequently met with, even in different cones of the same tree. 247. When a branch springs from a stem or parent axis, the spi- ral is continued from the leaves of the stem to those of the branch, so that the leaf from whose axil the branch arises begins the spire of that branch. When the spire of the branch turns in the same direction as that of the parent axis, as it more commonly does, it is said to be homodromous (from two Greek words, signifying like course) : when it turns in the opposite direction, it is said to be heterodromous (or of different course). 248. The cases represented by the fractions b 4; and | are theTHEIR ARRANGEMENT. 141 most stable and certain, as well as the easiest to observe. In the higher forms, the exact order of superposition often becomes uncer- tain, owing to a slight torsion of the axis, or to the difficulty of observing whether the 9th, 14th, 22d, 35th, or 56th leaf is truly over the first, or a little to the one side or the other of the vertical line. Indeed, if we express the angle of divergence in degrees and minutes, we perceive that the difference is so small a part of the circumference, that a very slight change will substitute one order for another. The divergence in TST = 138° 24'. In all those beyond, it i3 137° plus a variable number of minutes, which approaches nearer and nearer to 30'. Hence M. Bravais considers all these as mere alterations of one typical arrangement, namely, with the angle of divergence 137° 30' 28", which is irrational to the circumference, that is, not capable of dividing it an exact number of times, and con- sequently never bringing any leaf precisely in a right line over any preceding leaf, but placing the leaves of what we take for vertical ranks alternately on both sides of this line and very near it, approach- ing it more and more, without ever exactly reaching it. These forms of arrangement he therefore distinguishes as curviserial, be- cause the leaves are thus disposed on an infinite curve, and are never brought into exactly straight ranks. The others are correspondingly termed rectiserial, because, as the divergence is an integral part of the circumference, the leaves are necessarily brought into rectilineal ranks for the whole length of the stem. 249. A different series of spirals sometimes occurs in alternate leaves, viz. h I; i> fV ; and still others have been detected; but these are rare or exceptional cases. 250. Opposite Leaves (237, Fig. 210). In these, almost without exception, the second pair is placed over the intervals of the first, the third over the intervals of the second, and so on. More commonly, as in plants of the Labiate or Mint Family, the successive pairs cross each other exactly at right angles, so that the third pair stands directly over the first, the fourth over the second, &c., forming four equidistant vertical ranks for the FIG. 210. Opposite leaves of the Strawberry-bush, or Euonymus Americanus.142 TIIE LEAVES. whole length of the stem. In this case, the leaves are said to be decussate. In other cases, as in the Pink Family, often the succes- sive pairs deviate a little from this line, so that we have to pass several pairs before we reach one exactly superposed over the pair we start with. This indicates a spiral ar- rangement, which falls into some one of the modes already illustrated in alternate leaves' only that here each node bears a pair of leaves. 251. Vcrticillatc or Whorlcd leaves (Fig. 211) follow the same modes of arrangement as op- posite leaves. Sometimes they decussate, or the leaves of one whorl correspond to the intervals of that underneath, making twice as many vertical ranks as there are leaves in the whorl; sometimes they wind spirally, so that each leaf of the whorl belongs to as many parallel spirals, analogous to the secondary spirals in the case of alternate leaves. 252. The opposition or alternation of the leaves is generally constant in the same species, and often through the same family; yet both modes occasionally occur on the same stem, as in the common Snap- dragon and the Myrtle. All Exogens, having their cotyledons opposite, necessarily commence with that mode (Fig. 103-125); many retain it throughout; others change to alternation, either directly in the primordial leaves (Fig. 111“, 121), or at a later period. In Endogens, on the contrary, the first leaves are necessarily alternate (128), and it is seldom that they afterwards exhibit opposite or whorled leaves. The Pine in germination commences with a whorl of leaves (Fig. 133, 134) ; but the subsequent ones are alternate. The Pine, however (Fig. 212), and the Larch, bear what are termed 253. Fascicled Leaves. These are really the leaves of an axil- lary bud. They remain in a tuft or cluster because the axis of FIG. 211. Yerticillate or whorled leaves of a Galium or Bedstraw. FIG. 212. Piece of a branchlet of Pitch Pine, with three leaves in a fascicle or bundle, in the axil of a thin scale (a) which answers to a primary leaf. The bundle is surrounded at the base by a short sheath, formed of the delicate scales of the axillary bud.VERNATION OR PRAiFOLIATION. 143 the bud does not lengthen. This is plainly seen in the spring leaves of the Barberry and of the Larch (Fig. 213), crowded on short spurs, some of which soon elongate into ordinary shoots with scattered alternate leaves. Their nature is less evident in Pines, on account of the peculiar character of the leaves of the main axis, from whose axil the tuft of two, three, or five leaves arises, the primary leaf in this case being a thin and chaffy scale (Fig. 212, a) which soon falls off, while the actual foliage all be- longs to the axillary clusters. So in the common Barberry the prop- er leaves of the lengthened stems are chiefly in the form of spines (Fig. 29G), and the actual foliage appears in fascicles in their axils. 254. As regards their general position on the stem, leaves are said to be radical, when they are borne on the stem at or below the sur- face of the ground, so as apparently to grow from the root, as those of the Bloodroot, Plantain, Primrose, and of the acaulescent (154) Violets : those that arise along the main stem are termed cauline ; those of the branches, rameal; and those which stand upon or at the base of flower-branches are called floral; the latter, moreover, are generally termed bracts. 255. With respect to succession, those leaves which manifestly exist in the embryo are called seminal; the first or original pan- receiving the name of cotyledons (120), and usually differing wide- ly in appearance from the ordinary leaves which succeed them. The earliest ordinary leaves are termed primordial. These, as well as the cotyledons, usually perish soon after others are developed to supply their place. 256. As pertaining to the arrangement of leaves, we should here notice the modes in which they are disposed before expansion in the bud; namely, their 257. Vernation or Praefoliation. The latter is the most character- istic name, but the former, given by Linnseus (literally denoting their spring state), is the more ancient and usual. Two things are included under this head : — 1st, the mode in which each leaf con- sidered separately is disposed; 2d, the arrangement of the several FIG. 213. Piece of a branchlet of the Larch, with two fascicles of leaves.144 THE LEAVES. leaves of the same bud in respect to each other. This last is evi- dently connected with phyllotaxis, or their position and order of succession on the stem. As to the first, leaves are for the most part either bent or folded, or rolled up in vernation. Thus, the upper part may be bent on the lower, so that the apex of the leaf is brought down towards the base, as in the Tulip-tree, when the leaves are inflexed or reclinate in vernation ; or the leaf may be folded along its midrib or axis, so that the right half and the left half are applied together, as in the Oak and the Magnolia, when the leaves are conduplicate ; or each leaf may be folded up a cer- tain number of times like a fan, as in the Maple, Currant, and Vine, when they are said to be plicate or plaited. The leaf may be rolled either parallel with its axis, or on its axis. In the latter case it is spirally rolled up from the apex towards the base, like a crosier, or circinnate, as in true Ferns (Fig. 100), and among Phamoga- mous plants in the Drosera or Sundew. Of the former there are three ways ; viz. the whole leaf may be laterally rolled up from one edge into a coil, with the other edge exterior, when the leaves are said to be convolute, as in the Apricot and Cherry; or both edges may be equally rolled towards the midrib ; either inwards, when they are involute, as in the Violet and the Water-Lily ; or else out- wards, when they are revolute, as in the Rosemary and Azalea. Fig. 214-219 are Linnaian diagrams of sections of leaves, illustrating the principal modes of vernation. 258. Considered relatively to each other, leaves are valvate in vernation when corresponding ones touch each other by their edges the leaves are plane or convex, or at least not much bent or rolled. 214 215 216 only, without overlap- ping : they are imbri- cated when the outer successively overlap the inner, by their edges at least, in which case the order of over- lapping exhibits the phyllotaxis, or order of succession and po- sition. In these cases FIG. 214. Conduplicate; 215. Plicate or plaited; 216. Convolute; 217. Revolute; 218, Involute ; and, 219. Circinate, vernation.THEIR STRUCTURE AND CONFORMATION. 145 When leaves with their margins involute are applied together in a circle without overlapping, the vernation is induplicate. When, in conduplicate leaves, the outer successively embrace or sit astride of those next within, the vernation is equitant, as the leaves of the Iris at their base (Fig. 296) ; or when each receives in its fold the half of a corresponding leaf folded in the same manner, the vernation is half-equitant or obvolute. These terms equally apply to leaves in their full-grown condition, whenever they are then so situated as to overlie or embrace one another. They likewise apply to the parts in the flower-bud, under the name of aestivation or prsefloration. Chap. IX. Sect. V. Sect. II. Their Structure and Conformation. 259. Anatomy of the Leaf. The complete leaf consists of the Blade (Lamina or Limb, Fig. 229, b), with its Petiole or Leaf- stalk, p, and at its base a pair of Stipules, st. Of these the latter are frequently absent altogether, and in many cases where they originally exist they fall away as the leaf expands. The petiole is very often wanting; when the leaf is sessile, or has its blade rest- ing immediately on the stem that bears it (as in Fig. 210, 211). Sometimes, moreover, there is no proper blade, but the whole organ is cylindrical or stalk-like. It is the general characteristic of the leaf, however, that it is an expanded body. Indeed, it may be viewed as a contrivance for increasing the green surface of a plant, so as to expose to the light and air the greatest practicable amount of paren- chyma containing the green matter of vegetation (chlorophyll, 92), upon which the light exerts its peculiar action. Leaves as foliage, accordingly, are what we are now principally to consider, 260. In a general, mechanical way, it may be said leaves are defi- nite protrusions of the green layer of the bark, expanded horizon- tally into a thin lamina, and stiffened by tough, woody fibres (con- nected both with the liber, or inner bark, and the wood), which form its framework, ribs, or veins. Like the stem, therefore, the leaf is made up of two distinct parts, the cellular and the woody. The cellular portion is the green pulp or parenchyma: the woody, is the skeleton or framework which ramifies among and strengthens the former. The woody or fibrous portion fulfils the same purposes in the leaf as in the stem, not only giving firmness and support to the 13146 THE LEAVES. delicate cellular apparatus, but also serving for the conveyance and distribution of the sap. The subdivision of these ribs, or veins, of the leaf, as they are not inappropriately called, continues beyond the limits of unassisted vision, until the bundles or threads of woody tissue are reduced to very delicate fibres, ramified throughout the green pulp. 261. The cellular portion of the leaf consists of thin-walled cells of loose parenchyma, containing grains of chlorophyll, to which the green color of foliage is entirely owing. The cells are not heaped promiscuously, but exhibit a regular arrangement; upon a plan, too, which varies in different parts of the leaf, according to the different conditions in which it is placed. 262. Leaves are almost always expanded horizontally, so as to present one surface to the ground and the other to the sky ; and the parenchyma forms two general strata, one belonging to the upper and the other to the lower side. The microscope displays a manifest difference in the parenchyma of these two strata. That of the upper stratum is composed of one or more compact layers of oblong cells, placed endwise, or with their long diameter perpen- dicular to the surface ; while that of the lower stratum is very loosely arranged, leaving numerous vacant spaces between the cells ; and when the cells are oblong, their longer diameter is parallel with the epidermis. This is shown in Fig. 7, which represents a magnified section through the thickness (perpendicular to the surface) of a leaf of the Star-Anise of Florida; where the upper stratum of parenchyma consists of only a single series of perpendicular cells. Also in Fig. 220, which represents a similar view of a thin slice of a leaf of the Gar- den Balsam. Fig. 221 repre- sents a piece cut out of a leaf of the White Lily ; where the upper stratum is composed of only one compact layer of ver- tical cells. The parenchyma is alone represented ; the woody por- tion, or veins, being left out. The more compact structure of the FIG 220. Magnified section through the thickness of a leaf of the Garden Balsam i a, sec- tion of the epidermis of the upper surface ; 6, of the upper stratum of parenchyma c, of the lower stratum ; d, of the epidermis of the lower surface. (After Brongniart.)THEIR ANATOMICAL STRUCTURE. 147 upper stratum shows why the upper surface of leaves is of a deeper green than the lower. 263. The object which this arrangement subserves will appear evident, when we consider that the spaces between the cells, filled with air, communicate freely with each other throughout the leaf, and also with the external air by means of openings in the epider- mis (presently to be described); and when we consider the powerful action of the sun to promote evaporation, especially in dry air; and that the thin walls of the cells, like all vegetable membrane, allow of the free escape of the contained moisture by transudation. The compactness of the cells of that stratum which is presented immedi- ately to the sun, and their vertical elongation, so that each shall expose the least possible surface, obviously serve to protect the loose parenchyma beneath from the too powerful action of direct sunshine. This provision is the more complete in the case of plants which retain their foliage through a season of drought in arid re- gions, where the soil is usually so parched during the dry season, that, for a long period, it affords only a scanty supply of moisture to the roots. Compare, in this respect, a leaf of the Lily (Fig. 221), where the upper stratum contains but a single layer of barely oblong cells, with the firm and more enduring leaf of the Oleander, the upper stratum of which consists of two layers of long and narrow vertical cells as closely compacted as possible (Fig. 222). So dif- FIG. 221. A magnified section through the thickness of a minute piece of the leaf of the White Lily of the gardens, showing also a portion of the under side with some breathing-pores.148 TIIE LEAVES. ferent is the organization of the two strata, that a leaf soon perishes if reversed so as. to expose the lower surface to direct sunshine. 264. A further and more effectual provision for restraining the perspiration of leaves within due limits is found in the Epidermis, or skin, that invests the leaf, as it does the whole surface of the vege- table (69), and which is so readily detached from the succulent leaves of such plants as the Stonecrop and the Live-for-ever (Sedum) of the gardens. The epidermis is composed of small cells belonging to the outermost layer of cellular tissue, with the pretty thick-sided walls very strongly coherent, so as to form a firm membrane. Its cells contain no chlorophyll. In ordinary herbs that allow of ready evaporation, this membrane is made up of a single layer of cells ; as in the Lily, Fig. 221, and the Balsam, Fig. 220. It is composed of two layers in cases where one might prove insufficient; and in the Oleander, besides the provision against too copious evaporation, already described (263), the epidermis consists of three com- pact layers of very thick-sided cells (Fig. 222). It is generally thick, or hard and impermeable, in the firm leaves of the Pitto- sporum, Laurustinus, and other plants, which will thrive, for this very reason, where those of more delicate foliage are liable to per- ish, in the dry atmosphere of our rooms in winter. FIG 222. Magnified section through a part only of the thickness of a leaf of the Oleander, showing the epidermis of the upper surface, formed of three layers of thick-walled cells and the two very compact layers of cylindrical cells standing endwise. FIG. 223. Magnified slice of the epidermis and superficial parenchyma of a Cactus, after Schleiden ; exhibiting the epidermis (a) greatly thickened by a stratified deposition in the cells : and some cells of the parenchyma likewise nearly filled with an incrusting deposit. The depo- sition in such cases is always irregular, leaving canals or passages which nearly connect the adjacent cells. Several of the cells contain crystals (94). FIG. 224 Similar section from another species of Cactus, passing through one of the sto- mata, and the deep intercellular space beneath it.THEIR ANATOMICAL STRUCTURE. 149 265. In such firm leaves, especially, the walls of the epidermal cells are soon thickened by internal deposition (44), especially on the superficial side. This is well seen in the epidermis of the Aloe, and in other fleshy plants, which hear severe drought with impunity : in Fig. 223, it is shown, at a, in the rind of a Cactus, in which the green layer of the whole stem answers the purpose of leaves. Sometimes an exterior layer of this superficial deposit in the epidermis may be detached in the form of a continuous, ap- parently structureless membrane, which Brongniart and succeeding authors have called the Cuticle. That it may shed water readily, the surface of leaves is commonly protected by a very thin varnish of wax, or else with a bloom of the same substance in the form of a whitish powder, which easily rubs off (85), as is familiarly seen in a Cabbage-leaf. 266. A thickening deposit sometimes takes place in the cells of parenchyma immediately underneath the epidermis, especially in the Cactus Family, where the once thin and delicate walls of the cells become excessively and irregularly thickened (Fig. 223, 224), so as doubtless to arrest or greatly obstruct exhalation through the rind. Something like this choking of the cells must commonly occur with age in most leaves, particularly those that live for more than one season (311). 267. But the multiplication of these safeguards against exhalation might be liable to defeat the very objects for which leaves are prin- cipally destined. Evaporation from the parenchyma of the leaves is essential to the plant, as it is the only method by which its exces- sively dilute food can be concentrated. Some arrangement is requi- site that shall allow of sufficient exhalation from the leaves while the plant is freely supplied with moisture by the roots, but restrain it when the supply is deficient. It is clear that the greatest demand is made upon the leaves at the very period when the supply through the roots is most likely to fail; for the summer’s sun, which acts so powerfully on the leaves, at the same time parches the soil upon which the leaves (through the rootlets) depend for the moisture they exhale. So long as their demands are promptly answered, all goes well. The greater the force of the sun’s rays, the greater the speed at which the vegetable machinery is driven. But whenever the supply at the root fails, the foliage begins to flag and droop, as is so often seen under a sultry meridian sun ; and if the exhaustion pro- ceeds beyond a certain point, the leaves inevitably wither and perish. 13*150 THE LEAVES. Some adaptation is therefore needed, analogous to a self-acting valve, which shall regulate the exhalation according to the supply. Such an office is actually fulfilled by 268. The Stomata, Stomates, or Breatliing-pores (70). Through the orifices which bear this name, exhalation principally takes place, in all ordinary cases, where the epidermis is thick and firm enough to prevent much escape of moisture by direct transudation. The stomata (Fig. 225 — 228) are always so situated as to open directly into the hol- low chambers, or air-cavities, which pervade the parenchyma (Fig. 221), especially the lower stratum, so as to afford free communication between the external air and the whole interior of the leaf. The perforation of the epi- dermis is between two (or rarely four) delicate and commonly crescent-shaped cells, which, unlike the rest of the epidermis, usually contain some chlorophyll, and in other re- spects resemble the parenchyma beneath. When moistened these guardian-cells change their form, becoming more crescentic as they become more turgid, thereby separating in the middle and opening a free communication between the outer air and the interior of the leaf. As they become drier, they shorten and straighten, so as to bring the sides of the two into contact and close the orifice.* The use of this mechanism will be readily understood. So long as the leaf * They expand and contract most in the direction of their length; and the elongation and increased curvature when moist draws in the concave side and so enlarges the aperture. The mechanism of the opening and shutting of sto- mata has been recently investigated by Mohl (in Bot. Zeitung for 1856, p. 697, — an abstract of the memoir is given by C. F. Stone in Amer. Journal of Sci- ence for March, 1857), — and these facts verified. The peculiar change of the guardian-cells in form seems not entirely susceptible of mechanical explanation, and is partly controlled (like other vegetable movements) by the light of the sun; but it mainly depends upon endosmose. Mohl has clearly shown that, while the guardian-cells themselves act so as to open the stomate in moisture and close it in dryness, the adjacent cells of the epidermis in swelling when moist tend to close the stomate, and their contraction when dry to open it; — so that the actual position at any time is a resultant of nicely adjusted opposing forces. FIG. 225. A highly magnified piece of the epidermis of the Garden Balsam, with three stomata (after Brongniart).THEIR STOMATA OR BREATHING-PORES. 151 is in a moist atmosphere, and is freely supplied with sap, the sto- mates remain open, and allow the free escape of moisture by evap- oration. But when the supply fails, and the parenchyma begins to be exhausted, the guardian-cells, at least equally affected by the dry- ness, promptly collapse, and by closing these thousands of apertures check the drain the moment it becomes injurious to the plant. 269. As a general rule, the stomata wholly or principally belong to the epidermis of the lower surface of the leaf: the mechan- ism is too delicate to work well in direct sunshine. The posi- tion of the stomata, and the loose texture of the lower pa- renchyma, require that this sur- face should be shielded from the sun’s too direct and intense action; and show why leaves soon perish when artificially reversed, and pre- vented from resuming (as otherwise they spontaneously will) their natural position. This general arrangement is variously modified, however, under peculiar circumstances. The stomata are equally distributed on the two sides of those leaves, of whatever sort, which grow in an erect position, or present their edges, instead of their surfaces, to the earth and sky (294), and have the parenchyma of both sides similarly constituted, sustaining consequently the same relations to light. In the Water-Lilies (Nymphtea, Nupliar), and other leaves which float upon the water, the stomata all belong to the upper surface. All leaves which live under water, where there can be no evaporation, are destitute, not only of stomata, but usually of a distinct epidermis also. 270. The number of the stomata varies in different leaves from 800 to about 170,000 on the square inch of surface. In the Apple, there are said to be about 24,000 to the square inch (which is under the average number, as given in a table of 36 species by Lindley) ; so that each leaf of that tree would present about 100,000 of these orifices. When the stomata are not all restricted to the lower sur- face, still the greater portion usually occupy this position. Thus, the leaf of Arum Dracontium is said to have 8,000 stomata to a square inch of the upper surface, and twice that number in the FIG. 226, Magnified view of the 10,000th part of a square inch of the epidermis of the lower surface of the leaf of the White Lily, with its stomates. 227. A single stomate, more magnified. 228. Another stomate, widely open.152 THIS LEAVES. same space of the lower. The leaf of the Coltsfoot has 12,000 stomata to a square inch of the lower epidermis, and only 1,200 in the upper. That of the White Lily has from 20,000 to 60,000 to the square inch on the lower surface, and perhaps 3,000 on the up- per. In this plant, and in other true Lilies, they are so remarkably large (Fig. 221, 22G - 228) that they may be discerned by a simple lens of an inch focus. In most plants they are very much smaller than this. 271. Succulent or fleshy plants, such as those of the Cactus tribe, Mesembryanthemums, Sedums, Aloes, &c., are remarkable for holding the water they imbibe with great tenacity, rather in consequence of the thickness of the epidermis, or from the deposit which early ac- cumulates in the superficial cells of the parenchyma (266), than from the want of stomata. The latter are usually abundant,* but they seem to open less than in ordinary plants, except in young and growing parts. Hence the tissue becomes gorged as it were with fluid, which is retained with great tenacity, especially during the hot season. They are evidently constructed for enduring severe droughts ; and are accordingly found to inhabit dry and sunburnt places, such as the arid plains of Africa, — the principal home of the Stapelias, Aloes, succulent Euphorbias, &c., — or the hottest and driest parts of our own continent, to which the whole Cactus family is indigenous. Or, when such plants Inhabit the cooler temperate regions, like the Sedums and the common Houseleek, &c., they are commonly found in the most arid situations, on naked rocks, old walls, or sandy plains, exposed to the fiercest rays of the noonday sun, and thriving-where ordinary plants would speedily perish. The drier the atmosphere, the greater their apparent reluctance to part with the fluid they have accumulated, and upon which they live during the long period when little or no moisture is yielded toy the soil or the air. Their structure and economy fully explain tneir tolerance of the very dry air of our houses in midwinter, when or- dinary thin-leaved plants become unhealthy or perish. 272. Sometimes the leaves of succulent plants merely become obese or misshapen, like those of the Ice-plant and other species * The thickened epidermis of the fleshy leaves of the Sea-Sandwort (Hon- kenya) is provided with an abundance of largo stomata, on the upper as well as the lower face. But this plant, though very fleshy, grows in situations where its roots are always supplied with moisture.THEIR DEVELOPMENT, ETC. 153 of Mesembryanthemum, &e.: sometimes they are reduced to tri- angular projections or points, or are perfectly confounded wilh the green hark of the stem, which fulfils their office, as in the Stapelia and most Cacti. 273. The Development of Leaves. At their first appearance, each leaf is a minute papilla or projection of parenchyma on the nascent axis : as it grows, this shapes itself into the blade, and is eliminated from the axis. The petiole, if any, is later formed, and by its growth raises the blade from the stem. Commonly the apex of the blade first appears, and the formation proceeds from above down- wards. The sheath at the base (as in most Monocotyledons), or the stipules (259, which principally belong to Dicotyledons), are at first continuous with the blade, or divided from it by a mere con- striction : the formation and elongation of the petiole soon separate them. The stipules, remaining next the axis or source of nourish- ment, undergo a rapid development early in the bud, so that, at a certain stage, they are often larger than the body of the leaf, and they accordingly form in such cases the teguments of the bud. Divided or lobed and compound leaves are simple at the commence- ment, but the lobes are very early developed; they grow in respect to the axis of the leaf nearly as that grew from the axis of the plant, and in the compound leaf at length isolate themselves, and are often raised on footstalks of their own. Commonly the upper lobes or leaflets are first formed, and then the lower: but in those of the Walnut and Ailanthus, and other large compound leaves, the formation proceeds from below upwards, and new leaflets continue to be produced from the apex, even after the lowermost are nearly full grown. In the earliest stage leaves consist of parenchyma alone: the fibro-vascular tissue which makes the ribs, veins, or framework appears later. 274. At the points on the surface of the developing leaf where stomata are about to be formed, one of the epidermal cells early ceases to enlarge and thicken with the rest, but divides into two (in the manner formerly described, 33), forming the two guardian-cells of the stomate : as they grow, the two constituent portions of their common partition separate, leaving an interspace or orifice between. In some cases, each new cell divides again, when the stomate is formed of four cells in place of two. 275. The Forms of Leaves are almost infinitely various. These afford some of the readiest, if not the most certain, marks for154 THE LEAVES. characterizing species. Their principal modifications are therefore classified, minutely defined, and embodied in a system of nomen- clature which is equally applicable to other parts of the plant, and which as an instrument is indispensable to the systematic botanist. The numerous technical terms which have gradually accumulated from the infancy of the science, and have multiplied with its increas- ing wants, are mostly quite arbitrary, or have been suggested by real or fancied resemblances of their shapes to various natural or other objects. This arbitrary nomenclature, which formerly severe- ly tasked the memory of the student, was reduced by De Candolle to a clear and consistent system, based upon scientific principles, and of easy application. The fundamental idea of the plan is, that the almost infinite varieties in the form and outline of leaves may be deduced from the different modes and degrees in which the woody skeleton or framework of the leaf is expanded or ramified in the parenchyma. Upon this conception the following sketch is based; in which all the more important terms of the nomenclature of leaves are mentioned and defined. It should be kept in mind, however, that this is not to be taken as an explanation of the actual formation of leaves; but rather as an account of the mutual adap- tation and correspondence of their outlines and framework. For the parenchyma is developed, and the form of the leaf more or less determined, before the framework has an existence. The latter, therefore, cannot have given rise to the outline or shape of the organ. The distribution of the veins or fibrous framework of the leaf in the blade is termed its 27 6. Venation. The veins are distributed throughout the lamina in two principal modes. Either the vessels of the petiole divide at once, where they enter the blade, into several veins, which run parallel with each other to the apex, connected only by simple transverse veinlets (as in Fig. 230) ; or the petiole is continued into the blade in the form of one or more principal or coarser veins, which send oft’ branches on both sides, the smaller branch- lets uniting with one another (anastomosing) and forming a kind of network; as in Fig. 229. The former are termed parallel- veined, or commonly nerved leaves ; the veins in this case having been called nerves by the older botanists, — a name which it is found convenient to retain, although of course they are in no respect analogous to the nerves of animals. The latter are termed reticu- lated or netted-veined leaves.TIIEIR VENATION. 155 277. Parallel-veined or nerved leaves are characteristic of En- dogenous plants; while reticulated leaves are almost universal in Exogenous plants. We are thus furnished with a very obvious, al- though by no means absolute, distinction between these two great classes of plants, independently of the structure of their stems (198). 278. In reticulated leaves, the coarse primary veins (one or more in number), which proceed immediately from the apex of the petiole, are called ribs; the branches are termed veins, and their subordinate ramifications, veinlets. Very frequently, a single strong rib (called the midrib), forming a continuation of the petiole, runs directly through the middle of the blade to the lipex (Fig. 229, 238, &c.), and from it the lateral veins all diverge. Such leaves are termed feather-veined or pinnately veined; and are subject to vari- ous modifications, according to the arrangement of the veins and vein- lets ; the primary veins sometimes passing straight from the midrib to the margin, as in the Beech and Chestnut (Fig. 238) ; while in other cases they are divided into veinlets long before they reach the margin. When the midrib gives off a very strong primary vein or branch on each side above the base, the leaf is said to be triple- ribbed, or often tripli-nerved, as in the common Sunflower (Fig. FIG. 229. A leaf of the Quince, of the netted-veined or reticulated sort: ft, blade: p, petiole or leaf-stalk: st, stipules. FIG. 230. Parallel-veined leaf of the Lily of the Valley. b 229 230156 THE LEAVES. 241) ; if two such ribs proceed from each side of the midrib, it is said to be quintuple-ribbed, or quintupli-nerved. 231 232 233 231 235 239 238 239 240 241 242 243 279. Not unfrequently the vessels of a reticulated leaf divide at the apex of the petiole into three or more portions or ribs of nearly equal size, which are usually divergent, each giving off veins and veinlets, like the single rib of a feather-veined leaf. Such leaves are termed radiated-veined, or ptalmatehj-veined; and, as to the number of the ribs, are called three-ribbed, five-ribbed, seven-ribbed, &c. (Fig. 244, 247, 253). Examples of this form are furnished by the Maple, the Gooseberry, the Mallow family, &c. Occasionally the ribs of a radiated-veined leaf converge and run to the apex of the blade, as in Rhexia and other plants of the same family, thus resem- bling a parallel-veined or nerved leaf; from which, however, it is distinguished by the intermediate netted veins. But when the ribs are not very strong, such leaves are' frequently said to be nerved, although they branch before reaching the apex. 280. According to the theory of De Candolle (275), the shape which leaves assume may be viewed as dependent upon the dis- tribution of the veins, and the quantity of parenchyma; the gen- eral outline being determined by the division and direction of the veins ; and the form of the margin, (whether even and continuous, or else interrupted by void spaces or indentations,) by the greater or FIG. 231-244. Various forms of simple leaves.TIIF-IR FORMS. 157 less abundance of the parenchyma in which the veins are distrib- uted. This view is readily intelligible upon the supposition that a 545 547 348 leaf is an expansion of soft parenchyma, in which the firmer veins are variously ramified. Thus, if the principal veins of a feather- veined leaf are not greatly prolonged, and are somewhat equal in length, the blade will have a more or less elongated form. If the veins are very short in proportion to the midrib, and equal in length, the leaf will be linear (as in Fig. 240) ; if longer in proportion, but still equal, the leaf will assume an oblong form (Fig. 242), which a slight rounding of the sides converts into an oval or ellip- tical outline. If the veins next the base are longest, and especially if they curve forward towards their extremities, the leaf assumes a lanceolate (Fig. 239), ovate (Fig. 241), or some intermediate form. On the other hand, if the veins are more developed beyond the mid- dle of the blade, the leaf becomes obovate (Fig. 232), or cuneiform (Fig. 235). In radiated or palmately veined leaves (Fig. 245-253), where the primary ribs are divergent, an orbicular or roundish out- line is most common. When some of the ribs or their ramifications are directed backwards, a recess, or sinus, as it is termed, is pro- duced at the base of the leaf, which, taken in connection with the general form, gives rise to such terms as cordate or heart-shaped (Fig. 244), reniform or kidney-shaped (Fig. 245), &c., when the posterior portions are rounded; and those of sagittate or arrow- headed (Fig. 252), and hastate or halberd-shaped (Fig. 250), when FIG. 246 - 253. Forms of simple, chiefly radiated-yeined leaves. 14158 THE LEAVES. the angles or lobes at the base diverge. The margins of the sinus are sometimes brought into contact and united, when the leaf be- comes peltate or shield-shaped (Fig. 248) ; the blade being attached to the petiole, not by its apparent base, but by some part of the lower surface. Two or three common species of Hydrocotyle plainly exhibit the transition from common radiated leaves into the peltate form. Thus, the leaf of H. Americana (Fig. 247) is round- ish-reniform, with an open sinus at the base, while in H. inter- rupta and H. umbellata (Fig. 248), the margins have grown to- gether so as*to obliterate the sinus, and an orbicular peltate leaf is produced. In nerved leaves, when the nerves run parallel from the base to the apex, as in Grasses (Fig. 287), the leaf is necessa- rily linear, or nearly so ; but when they are more divergent in the middle, or towards the base, the leaf becomes oblong, oval, or ovate, &c. (Fig. 243). In one class of nerved or parallel-veined leaves, the simple veins or nerves arise from a prolongation of the petiole in the form of a thickened midrib, instead of the base of the blade, constitut- ing the curvinerved leaves of De Candolle. This structure is almost universal in the Ginger tribe, the Arrowroot tribe, in the Banana, and other tropical plants; and our common Pontederia, or Pickerel-weed (Fig. 236), affords an illustration of it, in which the nerves are curved backwards at the base, so as to produce a cordate outline. 281. As to the margin and particular outline of leaves, they ex- hibit every gradation between the case where the blade is entire, that is, with the margin perfectly continuous and even (as in Fig. 243), and those where it is cleft or divided into separate portions. The convenient hypothesis of De Candolle connects these forms with the abundance or scantiness of the parenchyma, compared with the divergence and the extent of the ribs or veins ; on the supposition that, where the former is insufficient completely to till up the framework, lobes, incisions, or toothings are necessarily produced, extending from the margin towards the centre. Thus, in the white and the yellow species of Water Ranunculus, there appears to be barely sufficient parenchyma to form a thin covering for each vein and its branches (Fig. 251, the lowest leaf) ; such leaves are said to be filiformhj dissected, that is, cut into threads; the nomenclature in all these cases being founded on tin; conven- ient (but incorrect) supposition, that a leaf originally entire is cut into teeth, lobes, divisions, &c. If, while the framework remains the same as in the last instance, the parenchyma be more abun-THEIR FORMS. 159 dantly developed, as in fact happens in the upper leaves of the same species when they grow out of water, and is shown in the same figure, they are merely cleft or lobed. If these lobes grow together nearlv to the ex- of the development of leaves, however, proves that the parenchyma grows and shapes the outlines of the organ in its own way, irrespec- tive of the framework, which is, in fact, adapted to the parenchyma rather than the parenchyma to it. The principal terms which designate the mode and degree of division in simple leaves may now be briefly explained, without further reference to this or any other theory. 282. A leaf is said to be serrate, when the margin is beset with sharp teeth which point forwards towards the apex (Fig. 254) ; dentate, or toothed, when the sharp salient teeth are not directed towards the apex of the leaf (Fig. 255) ; and crenate, when the teeth are rounded (Fig. 248, 256). A slightly waved or sinuous margin is said to be repand (Fig. 257) ; a more strongly uneven margin, with alternate rounded concavities and convexities, is termed sinuate (Fig. 258). When the leaf is irregularly and sharply cut deep into the blade, it is said to be incised (Fig. 259) ; when the portions (or segments') are more definite, it is said to be lobed (Fig. 2G0, 264) ; and the terms two-lobed, three-lobed (Fig. 264),five-lobed, &c., express the number of the segments. If the incisions extend about to the middle of the blade, or somewhat deeper, and especially if the sinuses are acute, the leaf is said to be cleft (Fig. 261, 265) ; and the terms two-cleft, three-cleft (Fig. 265), &c. (or in the Latin form, bifid, trifid, &c.), designate the number of the segments : or when the latter are numerous or indefinite, the leaf is termed many-cleft, or multifid. If the segments extend nearly, but not quite, to the tire. The study FIG. 254 - 259. Forms of leaves as to the toothing of their margins.160 THE LEAVES. base of the blade or the midrib, the leaf is said to be parted (Fig. 262, 266) : if they reach the midrib or the base, so as to interrupt 260 261 262 263 the parenchyma, the leaf is said to be divided (Fig. 263, 267) ; the number of partitions or divisions being designated, as before, by the terms two-, three-, five-parted, or two-, three-, five-divided, &c. 283. As the mode of division always coincides with the arrange- ment of the primary veins, the lobes or incisions of feather-veined, are differently arranged from those of radiated or palmately veined leaves : in the latter, the principal incisions are all directed to the base of the leaf; in the former, towards the midrib. These modi- fications are accurately described by terms indicative of the vena- tion, combined with those that express the degree of division. Thus, a feather-viened (in the Latin form, a pinnately veined) leaf is said to be pinnately cleft or pinnatifid (Fig. 261), when the sinuses reach half-way to the midrib ; pinnately parted, when they extend almost to the midrib (Fig. 262) ; and pinnately divided, when they reach the midrib, dividing the parenchyma into separate portions (Fig. 263). A few subordinate modifications are in- dicated by special terms: thus, a pinnatifid or pinnately parted leaf, with regular, very close and narrow divisions, like the teeth of a comb, is said to be pectinate ; a feather-veined leaf, more or less pinnatifid, but with the lobes decreasing in size towards the base, is FIQ. 260 - 267. Pinnately and palmately lobed, cleft, parted, and divided leaves.THEIR FORMS. 161 termed lyrate, or lyre-shaped (Fig. 278) ; and a lyrate leaf with sharp lobes pointing towards the base, as in the Dandelion (Fig, 279), is called runcinate. A palmately veined leaf is in like man- ner said to be palmately loled (Fig. 264), palmately cleft (Fig. 265), palmately parted (Fig. 266), or palmately divided (Fig. 267), ac- cording to the degree of division. The term palmate was originally employed to designate a leaf more or less deeply cut into about five spreading lobes, bearing some resemblance to a hand with the fingers spreading; and it is still used to designate a palmately lobed leaf, without reference to the depth of the sinuses. A palmate leaf with the lateral lobes cleft into two or more segments is said to be pedate (Fig. 249), from a fancied resemblance to a bird’s foot. By desig- nating the number of the lobes in connection with the terms which indicate their extent and their disposition, botanists are enabled to describe all these modifications with great brevity and precision. Thus, a palmately three-parted leaf is one of the radiated-veined kind, which is divided almost to the base into three segments (Fig. 266) ; a pinnately five-parted leaf is one of the feather-veined kind cut into five lobes (two on each side, and one terminal), with the sinuses ex- tending almost to the midrib : and the same plan is followed in de- scribing cleft, lobed, or divided leaves. 284. The segments of a lobed or divided leaf may be again di- vided, lobed, or cleft, in the same way as the original blade, and the same terms are employed in describing them. Sometimes both the primary, secondary, and even tertiary divisions are defined by a single word or phrase; as hipinnatifid (Fig. 280), tripinnatifid, bipinnately parted, tripinnately parted, twice palmately parted, &c. 285. Parallel-veined or nerved leaves would naturally be ex- pected to present entire margins, and this they almost universally do when the nerves are convergent (Fig. 230, 243). Such leaves are often lobed or cleft when the principal nerves diverge greatly, as in the Dragon Arum; but the lobes themselves are entire. 268 269 270 271 272 273 274 275 276 286. There are a few terms employed in describing the apex of a leaf, which may be here enumerated. "When a leaf tapers to a FIG. 268-276. Forms of the apex of leaves. 14*162 THE LEAVES. narrowed or slender apex, it is said to be acuminate (Fig. 268) : when it terminates in an acute angle, it is said to be acute (Fig. 269) : when the apex is an obtuse angle, or rounded, it is termed obtuse (Fig. 270) : an obtuse leaf, with the apex slightly indented or depressed in the middle, is said to be refuse (Fig. 272), or, if more strongly notched, emarginate (Fig. 273) : an obovate leaf with a wider and more conspicuous notch at the apex is termed obcordate (Fig. 274), being a cordate or heart-shaped leaf inverted. When the apex is, as it were, cut otf by a straight transverse line, the leaf is said to be truncate (Fig. 271) : when abruptly terminated by a small and slender projecting point, it is mucronate (Fig. 27 6) : when tipped with a stronger and rigid projecting point, or cusp, it is cuspi- date (Fig. 275). 287. All these terms are equally applicable to expanded sur- faces of every kind, such as petals, sepals, &c.: and those terms which are used to describe the modifications of solid bodies, such as stems and stalks, arc equally applicable to leaves when these affect similar shapes, as they sometimes do. 288. The whole account, thus far, relates to Simple Leaves, namely, to those which have a blade of one piece, however cleft or lobed, or, if divided, where the separate portions are neither raised on 277 278 279 280 281 FIG. 277 - 287. Various forms of lobed and compound leaves.COMPOUND LEAVES. 163 stalklets of their own, nor articulated (by a joint) with the main petiole, so that the pieces are at length detached and fall separately. The distinction, however, cannot be very strictly maintained ; there are so many transitions between simple and 289. Compound Leaves. These have the blade divided into entire- ly separate pieces ; or, rather, they consist of a number of blades, borne on a common petiole, usually supported on stalklets of their own, between which and the main petiole an articulation or joint is formed, more or less distinctly. These separate blades are called Leaflets : they present all the diversities of form, outline, or division which simple leaves exhibit; and the same terms are em- ployed in characterizing them. Having the same nature and origin as the lobes or segments of simple leaves, they are arranged in the same ways on the common petiole. Compound leaves accordingly occur under two general forms, the pinnate and the palmate (other- wise called digitate). 290. The pinnate form is produced when a leaf of the pinnately veined sort becomes compound; that is, the leaflets are situated along the sides of the common petiole. There are several modifica- tions of the pinnate leaf. It is abruptly pinnate, when the leaflets are even in number, and none is borne on the very apex of the petiole or its branches, as in Cassia (Fig. 290), and also in the Yetch tribe, where, however, the apex of the petiole is generally prolonged into a tendril (Fig. 287, 289). It is impari-pinnate, or pinnate with an oddMeaflet, when the petiole is terminated with a FIG. 288-290. Simply pinnate leaves of various forms.164 THE LEAVES. leaflet (Fig. 281, 288). There are some subordinate modifications; such as lyrately pinnate, when the blade of a lyrate leaf (Fig. 278) is completely divided, as in Fig. 285 ; and interruptedly pinnate, when some minute leaflets are irregularly intermixed with larger ones, as is also shown to some extent in the figure last cited. The number of leaflets varies from a great number to very few. When reduced to a small number, such a leaf is said to be pinnately seven-, or jive-, or trifoliolate, as the case may be. A pinnate leaf of three or five leaflets is often called ternate or quinate ; which terms, how- ever, are equally applied to a palmately compound leaf, and also, and more appropriately, to the case of three or five simple leaves growing on the same node. A pinnately trifoliolate leaf (Fig. 286) is readily distinguished by having the two lateral leaflets attached to the petiole at some distance below its apex, and by the joint which is observable at some point between their insertion and the lamina of the terminal leaflet. Such a leaf may even be reduced to a single leaflet; as in the Orange (Fig. 283) and the primordial leaves of the common Barberry. This is distinguished from a really simple leaf by the joint at the junction of the partial with the general petiole. 291. The palmate or digitate form is produced when a leaf of the palmately veined sort becomes compound ; in which case the leaflets are necessarily all attached to the apex of the common petiole, as in the Horsechestnut and Buckeye (Fig. 277), and the common Clover (Fig. 304). Such leaves of three, five, or any definite number of leaflets, are termed palmately (or digitately) trifoliolate, five-foliolate, &c. A leaf of two leaflets, which rarely occurs, is unijugate (one- paired) or binate. By this nomenclature, the distinction between pinnately and palmately compound leaves is readily kept up, and every important character of a leaf is expressed with brevity and accuracy. 292. The stalk of a leaflet is called a partial petiole (petiolule) ; and the leaflet thus supported is petiolulate. The partial petioles may bear a set of leaflets, instead of a single one, when the leaf becomes doubly or twice compound. Thus a pinnate leaf again com- pounded in the same way becomes bipinnate (Fig. 282), or if still a third time divided it is tripinnate, &c. In these cases the main divisions or branches of the common petiole are called pinna, or the pairs jugae. So a trifoliolate leaf twice compound becomes biternate (Fig. 284) ; or thrice, triternate, &c. When the primary divisionVERTICAL AND PERFOLIATE LEAVES. 165 is digitate, the secondary division is often pinnate, thus combining the two modes in the same leaf. A leaf irregularly or indeter- minately several times compounded, in whatever mode, is said to be decompound. 293. leaves of Peculiar Conformation. The blade of a leaf is almost always symmetrical, that is, the portions on each side of the midrib or axis are similar; hut occasionally one side is more developed than the other, when the leaf is oblique, as is strikingly the case in the species of Begonia (Fig. 246) of our conservatories. 294. Vertical and Equitant leaves. The blade is also commonly horizontal, presenting one surface to the sky, and the other to the earth; in which case the two surfaces differ in structure (262) as well as in appearance, each being fitted for its peculiar of- fices : if artificially reversed, they spontaneously resume their natural position, or soon perish if prevented from doing so. But in erect and verti- cal leaves, the two surfaces are equally exposed to the light, and are similar in structure and ap- pearance. In such erect and equita7it leaves as those of Iris (Fig. 291), it is really the lower sur- face that is presented to the air; for the leaf is folded together lengthwise (conduplicate), and consoli- dated while in the nascent state, so that the true upper surface is concealed in the interior, except near the base, where they alternately cover over each other in the equitant manner (258, Fig. 292). True vertical leaves, which present their edges instead of their surfaces to the earth and sky, generally assume this position by a twisting of the base or the petiole ; as is strikingly seen in the Callistemon and many other Australian trees of the Myrtle family, some of which are now com- mon in green-houses. 295. Perfoliate Leaves. While in Iris the two halves of the FIG. 291. Equitant erect leaves of Iris, with the rootstock. FIG. 292. A section across these leaves at the base, showing their equitant character.1G6 THE HEAVES, upper surface of a folded leaf cohere, those of some other plants ex- hibit a cohesion by their contiguous edges, and give rise to a differ- ent anomaly. This is illustrated by peltate leaves (Fig. 248), and more strikingly by what are termed perfoliate leaves. These in some cases originate from the union of the bases of a pair of opposite sessile leaves (con- nate-perfoliate), as in Silphium perfoliatum, Triosteum perfo- liatum, and the upper pairs of true Honeysuckle (Fig. 294). In others they con- sist of a single clasping leaf, the posterior lobes of which encompass the stem and cohere on the opposite side, as is seen in Bu- pleurum rotundifolium, Uvularia perfo- liata, and Baptisia perfoliata (Fig. 293). 296. Leaves with no distinction of Blade and Petiole. The leaves of the Iris, as well as those of the Daffodil, the Onion, and of many other Endogens, show no distinction of blade and petiole. In some the leaf of this sort may be regarded as a sessile blade ; in others, rather as a petiole per- forming the functions of a blade. Leaves are not always expanded bodies. Sometimes they are filiform or thread-shaped, as those of Asparagus : some are acicidar, acerose, or needle-shaped, as in Pines and Larches (Fig. 212, 213) ; others are subulate or awl-shaped, as in Juniper, &c. The Red Cedar and Arbor Vit® (Fig. 295) exhibit both awl-shaped and scale-shaped leaves on different branchlets. 297. Succulent or Fleshy Leaves, like those of Stonecrop, Ilouse- leek, Mesembryanthemum or Ice-Plant, and the Agave or Century- Plant, usually assume shapes more or less unlike ordinary foliage. Some of them are terete, like stems, or at least have no distinct upper and lower surface. These greatly thickened leaves serve a FIG. 293. Perfoliate (single) leaves of Baptisia perfoliata. FIG. 294. Connate-perfoliate leaves of a wild Honeysuckle (Lonicera flava).AS BUD-SCALES, TENDRILS, SPINES, ETC. 167 double purpose, being not only organs for assimilation, — the general office of foliage, — but also repositories in which assimilated matter is stored up, just as in the root of the Beet and Radish (Fig. 138), or in subter- ranean stems or branches in rootstocks, tubers, and corms (188 -190,194). The bases of those leaves which form the scales of bulbs (191) are turned to the same use. In Fig. 176 we have a leaf the blade of which acts as foliage in the ordi- nary manner of leaves, while its subterranean thickened base serves as a repository of nutri- ment which the blade has elaborated. The very first leaves of the plant, viz. the cotyledons or seed-leaves (120-123) are commonly subservi- ent to tills purpose, and some- times to no other, as in the Pea, Horsechestnut, Oak, &c. (124), where these leaves are mere repositories of food for the use of the germinating plant. 298. Leaves as Bud-scales, &c. (161) exhibit the same organ under a different modification, and subserving a different special purpose. Of the same nature are the degenerated or abortive scale-like leaves on the vernal stems of peren- nial herbs near or beneath the surface of the ground, and on Asparagus shoots, and also those scales which colored parasitic plants produce in place of foliage (152). The primary leaves of Pines are all thin and dry bud-scales; the actual foliage originating from a branch in the axil of each (Fig. 212). 299. Leaves as Tendrils are seen in the proper Pea tribe ; where however only the extremity of the common petiole is transformed in this as manner (Fig. 287, 289); but in one plant of the kind (Lathyrus Apliaca) the whole leaf becomes a tendril. 300. Leaves as Spines occur in several plants. The primary leaves FIG. 295. A twig of American Arbor Vitas, exhibiting both awl-shaped and scale-shaped leaves. FIG. 296. A summer shoot of the Barberry, showing a lower leaf in the normal state ; the next partially, those still higher completely, transformed into spines.1C8 THE LEAVES, of the shoots of the common Barberry offer a familiar instance of the kind (Fig. 296). The most extraordinary modification of the leaf occurs in the 301. Fly-traps of Dionaea muscipula, the Venus’s Fly-trap of North leaf of this most curious plant bears at its summit an append- age (answering, perhaps, to the proper blade), which opens and shuts : fringed with strong bristles or slender teeth on its margin, it bears some resemblance to a steel-trap, and operates much like one. For when open, as it commonly is when the sun shines, no sooner does a fly alight on its surface, and brush against any one of the several long bristles that grow there, than the trap suddenly closes, often capturing the intruder, pressing it all the harder for its struggles, and commonly depriving it of life. After all movement has ceased within, the trap slowly opens, and is ready for another capture. Why this plant catches insects, we are unable to say; and as to the mechanism of the movement it is no more and no less explicable than the much slower movements of ordinary leaves in changing their position. FIG. 297. A plant of Dionasa muscipula, reduced in size. 298. Three of the leaves, of nearly the natural size ; one of them open, the others closed.AS ASCIDIA OR PITCHERS. 169 302. Ascidia or Pitchers, or tubes open at the summit, represent another remarkable form of leaves. These occur in several plants of widely different families. If we conceive the margins of the dilated part of the leaf of Dionata to curve inwards until they meet, and cohere with each other, there would result a leaf in form not unlike that of Sarracenia purpurea, the common Pitcher-plant or Sidesaddle Flower of the Northern United States (Fig. 300). So the tube or pitcher has been supposed to answer to the petiole, and the hood at the summit to the blade. And this view is strengthened by a Pitcher-plant of the same family (Heliamphora, Fig. 299), discovered by Mr. Schomburgk in the mountains of British Guiana, in which the pitcher is not always completed quite to the summit, and the hood is represented by a small concave terminal appendage. In the curious Nepenthes (Fig. 301), the petiole is first dilated into a kind of lamina, then contracted into a tendril, and finally dilated into a pitcher, containing fluid secreted by the plant itself; the orifice being accurately closed by a lid, which from analogy was supposed to represent the real blade of the leaf. The study of the development, however (recently made by Dr. Hooker), does not confirm this hypothesis. The whole pitcher of Nepenthes is only an anom- alous appendage of the tendril-like prolongation of the midrib of the real blade of the leaf. A new Pitcher-plant of the Sarracenia family (the Darlingtonia), discovered by Mr. Brackenridge in California, FIG. 299. Pitchers of Heliamphora; 300, of Sarracenia purpurea; 301, of Nepenthes. 302. A phyllodium of a New Holland Acacia. 303. The same, bearing a reduced compound blade. 15170 THE LEAVES. has recently been made known by Dr. Torrey. In this the enlarged summit of the tube is strongly arched like a hood (as in Sarracenia psittacina of the Southern States), and is abruptly terminated by a singular two-lobed foliaceous appendage, resembling the forked tail of a fish. 303. The Petiole, or leafstalk, is usually either round, or half-cylin- drical and channelled on the upper side. But in the Aspen, it is strongly flattened at right angles with the blade, so that the slightest breath of air puts the leaves in motion. It is not unfrequently fur- nished with a leaf-like border, or ring ; which, in the Sweet Pea of the gardens, extends downward along the stem, on which the leaves are then said to be decurrent; or the stalk or stem thus bordered is said to be alate or winged. In many Umbelliferous plants, the petiole is dilated below into a broad and membranaceous inflated sheath; and in a great number of Endogenous plants the petiole consists of a sheath, embracing the stem, which in Grasses is fur- nished at the summit with a membranous appendage, in some sort equivalent to the stipules, called the ligule (Fig. 237). The woody and vascular tissue runs lengthwise through the petiole, in the form usually of a definite number of parallel threads, to be ramified in the blade. The ends of these threads are apparent on the base of the leafstalk when it falls off, and on the scar left on the stem, as so many round dots (Fig. 153, b), of a uniform number and arrange- ment in each species. 304. Phyllodia (Fig. 302, 303). Occasionally the whole petiole dilates into a kind of blade, traversed by ribs, mostly of the parallel- veined kind. In these cases the proper blade of the leaf commonly disappears ; this substitute, called a Phyllodium (meaning a leaf-like body), taking its place. These phyllodia constitute the whole foliage of the numerous Australian Acacias. Here they are at once dis- tinguished from leaves with a true blade by being entire and parallel- veined ; while their proper leaves (of which the earlier ones uni- formly appear in germination, and also later ones in casual instances) are compound and netted-veined. They are also to be recognized by their uniformly vertical position, presenting their margins instead of their surfaces to the earth and sky; and they sometimes bear a true compound lamina at the apex, as in Fig. 303. 305. Stipules (259, Fig. 229) are lateral appendages of leaves, usually appearing as small foliaceous bodies, one on each side of the base of the petiole. They are not found at all in a great number ofSTIPULES. 171 plants ; but their presence or absence is usually uniform throughout a natural order. Stipules assume a great variety of forms analogous to those of the blade. Like it they are sometimes membranaceous or scale-like, and sometimes transformed into spines, as in the Locust- tree, &c. They are sometimes present on developing shoots only; as in the Beech, the Fig, and the Magnolia (Fig. 155, 156), where they form the covering of the buds, but fall away as the leaves expand. They have a strong tendency to cohere with each other, or with the base of the petiole. Thus, in the Clover (Fig. 304), the Strawberry, and the Rose (Fig. 281), a stipule ad- heres to each side of the base of the petiole ; in the Plane-tree, the two are free from the petiole, but cohere by their outer margins, so as to form an apparently single stipule opposite the leaf. In other cases, both margins are united, forming a sheath around the stem, just above the leaf: these are called intrafoliaceous stipules; and when membranaceous, as in Polygo- num (Fig. 305), they have been termed ochrece. When opposite leaves have stipules, they usually occupy the space between the petioles on each side, and are termed interpetiolar. The stipules of each leaf (one on each side), being thus placed in contact, frequently unite so as to form apparently but a single pair of stipules for each pair of leaves ; instances of which are very common in the order Rubiacese. 306. Leaves furnished with stipules are said to be stipulate: when destitute of them, ea'.stipulate. The leaflets of compound leaves are sometimes provided with small stipules (termed stipelles) of their own, as in the Bean (Fig. 286) ; when they are said to be stipellate. FIG. 304. A leaf of Red Clover, with its three leaflets at the summit of the leafstalk, to which at the base the stipules (st) are adherent, one on each side. FIG. 305. Part of a leaf of Polygonum orientale, with its stipules united into a sheath (oc/u-ea) and surrounding the stem.172 THE LEAVES. Sect. III. The Duration of Leaves, and the General Action of Foliage. 307. Leaves last only for a limited period, and are thrown off, or else perish and decay on the stem, after having fulfilled their office for a certain time. 308. Duration of Leaves. In view of their duration, leaves are called fugacious, when they fall off soon after their appearance ; deciduous, when they last only for a single season ; and persist- ent, when they remain through the cold season, or other interval during which vegetation is interrupted, and until after the appear- ance of new leaves, so that the stem is never leafless; as in Ever- greens. 309. Leaves last only for a single year in many Evergreens, as well as in deciduous-leaved plants ; the old leaves falling soon after those of the ensuing season are expanded, or, if they remain longer, ceasing to bear any active part in the economy of the vegetable, and soon losing their vitality altogether. In Pines and Firs, how- ever, although there is an annual fall of leaves either in autumn or spring, yet these were the produce of some season earlier than the last; and the branches are continually clothed with the foliage of from two to five, or even eight or ten, successive years. On the other hand, it is seldom that all the leaves of an herb endure through the whole growing season, the earlier foliage near the base of the stem perishing while fresh leaves are still appearing above. In our deciduous trees and shrubs, however, the leaves of the season are mostly developed within a short period, and they all perish nearly at the same time. They are not destroyed by frost, as is commonly supposed ; for they begin to languish, and often assume their autumnal tints (as happens with the Red Maple especially), or even fall, before the earlier frosts ; and when vernal vegetation is destroyed by frost, the leaves blacken and wither, but do not fall off entire, as they do in autumn. Some leaves are cast off, indeed, while their tissues have by no means lost their vital- ity. Death is often rather a consequence than the cause of the fall. Others die and decay on the stem without falling, as in Palms and most Endogens. In some cases many of the dead leaves hang on the branches through the winter, as in the Beech, falling only when the new buds expand, the following spring. WeTHEIR DEATH AND FALL. 173 must therefore distinguish between the death and the fall of the leaf. 310. The Fall of tllC Leaf is owing to an organic separation, through an articulation, or joint, which forms between the base of the petiole and the surface of the stem on which it rests. The forma- tion of the articulation is a vital process, a kind of disintegration of a transverse layer of cells, which cuts off the petiole by a regular line, in a perfectly uniform manner in each species, leaving a clean scar at the insertion (Fig. 153, 155). The solution of continuity begins in the epidermis, where a faint line marks the position of the future joint while the leaf is still young and vigorous : later, the line of demarcation becomes well marked, internally as well as ex- ternally ; the disintegrating process advances from without inwards, until it reaches the woody bundles ; and the side next the stem, which is to form the surface of the scar, has a layer of cells con- densed into what appears like a prolongation of the epidermis, So that, when the leaf separates, “ the tree does not suffer from the effects of an open wound.” “ The provision for the separation being once complete, it requires little to effect it; a desiccation of one side of the leafstalk, by causing an effort of torsion, will readily break through the small remains of the fibro-vascular bundles ; or the in- creased size of the coming leaf-bud will snap them ; or, if these causes are not in operation, a gust of wind, a heavy shower, or even the simple weight of the lamina, will be enough to disrupt the small connections and send the suicidal member to its grave. Such is the history of the fall of the leaf. We have found that it is not an ac- cidental occurrence, arising simply from the vicissitudes of tempera- ture and the like, but a regular and vital process, which commences with the first formation of the organ, and is completed only when that is no longer useful; and we cannot help admiring the wonder- ful provision that heals the wound even before it is absolutely made, and affords a covering from atmospheric changes before the part can be subjected to them.” * Leaves fall by an articulation in most Exogenous plants, where the insertion usually occupies only a moderate part of the circumference of the stem, and especially in those with woody stems which continue to increase in diameter. When they are not cast off in autumn, therefore, the disruption inevitably takes place the next spring, or whenever the circumfer- * Dr. Inman, in Henfrey’s Botanical Gazette, Yol. 1. p. 61. 15 *174 THE LEAVES. ence further enlarges. But in most Endogenous plants, where the leaves are scarcely, if at all, articulated with the stem, which in- creases little in diameter subsequent to its early growth, they are not thrown off, but simply wither and decay; their dead bases or petioles being often persistent for a long time. 811. The Death of the Leaf, however, in these and other cases, is still to be explained. Why have leaves such a temporary exist- ence ? Why in ordinary cases do they last only for a single year, or a single summer ? An answer to this question is to be found in the anatomical structure of the leaf, and the nature and amount of the fluid which it receives and exhales. The water continually absorbed by the roots dissolves, as it percolates the soil, a small portion of earthy matter. In limestone districts especially, it takes up a sensible quantity of carbonate and sulphate of lime, and be- comes hard. ■ It likewise dissolves a smaller proportion of silex, magnesia, potash, &c. A part of this mineral matter (44, 93) is at once deposited in the woody tissue of the stem ; but a larger por- tion is carried into the leaves, where, as the water is exhaled pure, all this earthy substance, not being volatile, must be left be- hind to incrust the delicate cells of the parenchyma, much as the vessels in which water is boiled for culinary purposes are in time incrusted with an earthy deposit. This earthy incrustation, in con- nection with the deposition of organic solidified matter, must grad- ually choke the tissue of the leaf, and finally unfit it for the per- formance of its offices. Hence the fresh leaves most actively fulfil their functions in spring and early summer; but languish towards autumn, and erelong inevitably perish. Hence, although the roots and branches may be permanent, the necessity that the leaves should be annually renewed. But the former are, in fact, annually renewed likewise ; and life abandons the annual layers of wood and bark almost as soon as it does the leaves they supply (224, 231), and for similar reasons ; although their situation is such that they become part of a permanent structure, and serve to convey the sap, even when no longer endowed with vitality. 312. The general correctness of this view may be tested by direct microscopical observation. In Fig. 223, 224, some superficial paren- chyma thus obstructed by long use is represented; and similar illustrations may be obtained from ordinary leaves. That this deposit consists in great part of earthy matter, is shown by care- fully burning away the organic materials of an autumnal leaf overEXHALATION AND THE RISE OF TIIE SAP. 175 a lamp, and examining the ashes by the microscope ; which will he found very perfectly to exhibit the form of the cells. The ashes which remain when a leaf or other vegetable substance is burned in the open air, represent the earthy materials which it has accu- mulated. A vernal leaf leaves only a small quantity of ashes ; an autumnal leaf yields a very large proportion, — from ten to thirty times as much as the wood of the same species ; although the leaves contain the deposit of a single season only, while the heart-wood is loaded with the accumulations of successive years.* 313. Exhalation from the Leaves. The quantity of water exhaled from the leaves during active vegetation is very great. In one of the well-known experiments of Hales, a Sunflower three and a half feet high, with a surface of 5,61G square inches exposed , to the air, was found to perspire at the rate of twenty to thirty ounces avoirdu- pois every twelve hours, or seventeen times more than a man. A Vine, with twelve square feet of foliage, exhaled at the rate of five or six ounces a day ; and a seedling Apple-tree, with eleven square feet of foliage, lost nine ounces a day. The amount varies with the degree of warmth and dryness of the air, and of exposure to light; and is also very different in different species, some exhaling more copiously even than the Sunflower. But when we consider the vast perspiring surface presented by a large tree in full leaf, it is evident that the quantity of watery vapor it exhales must be immense. This exhalation is dependent on the capacity of the air for moisture at the time, and upon the presence of the sun ; often it is scarcely perceptible during the night. The Sunflower, in the experiment of Hales, lost only three ounces in a warm, dry night, and underwent no diminution during a dewy night. 314. Rise of the Sap. Now this exhalation by the leaves requires a corresponding absorption by the roots. The one is the measure of the other. If the leaves exhale more in a given time than the roots can restore by absorption from the soil, the foliage droops ; we see in a hot and dry summer afternoon, when the drain by * The dried leaves of the Elm contain more than eleven per cent of ashes, while the wood contains less than two percent; those of the Willow, more than eight per cent, while the wood has only 0 45; those of the Beech, 6.69, the wood only 0.36 ; those of the (European) Oak, 4.05, the wood only 0.21 ; those of the Pitch-Pine, 3.15, the wood only 0.25 per cent. Hence the decaying foliage in our forests restores to the soil a large proportion of the inorganic matter which the trees from year to year take from it.176 THE LEAVES. exhalation is very great, while a further supply of moisture can hardly be extorted from the parched soil; — as we observe also in a leafy plant newly transplanted, where the injured rootlets are not immediately in a fit condition for absorption. Ordinarily, how- ever, exhalation by the leaves and absorption by the roots are in direct ratio to each other, and the loss sustained by the leaves is immediately restored (by endosmosis, 40) through the ascent of the sap from the branches, the latter being constantly supplied by the stem ; so that, during active vegetation, the sap ascends from the remotest rootlets to the highest leaves, at a rate corresponding to the amount of exhalation. The action of the leaves is, therefore, the principal mechanical cause of the ascent of the sap. This is well illustrated when a graft has a different time of leafing from that of the stock upon which it is made to grow, the graft wholly regulating the season or temperature at which the sap is put in motion, and controlling the habits of the original stock. Also by introducing the branches of a tree into a conservatory during winter; when, as their buds expand, the sap in the trunk without is set unseasonably into motion to supply the demand. 315. During the summer’s vegetation, while the sap is consumed or exhaled almost as fast as it enters the plant, no considerable ac- cumulation can take place : but in autumn, when the leaves perish, the rootlets, buried in the soil beyond the influence of the cold, which checks all vegetation above ground, continue for a time slowly to absorb the fluid presented to them. Thus the trunks of many trees are at this season gorged with sap, which will flow from in- cisions made into the wood. This sap undergoes a gradual change during the winter, and deposits its solid matter in the cells of the wood. The absorption recommences in the spring, before new leaves are expanded to consume the fluid ; chemical changes take place ; the soluble matters in the tissue of the stem are redissolved, and the trunk is consequently again gorged with sap, which will flow, or bleed, when wounded. But when the leaves resume their functions, or when flowers are developed before the leaves appear, as in many forest-trees, this stock of rich sap is rapidly consumed, and the sap will no longer flow from an incision. It is not, there- fore, at the period when the trunk is most gorged with sap, in spring and autumn, but when least so, during summer, that the sap is prob- ably most rapidly ascending.PHYSIOLOGY OF VEGETATION. 177 CHAPTER YI. OF THE FOOD AND NUTRITION OF PLANTS. Sect. I. The General Physiology of Vegetation. 316. The Organs of Vegetation or Nutrition (those by which plants grow and form their various products) having now been con- sidered, both as to their structure and to some extent as to their action, we are prepared to take a comprehensive survey of the general results of vegetation; to inquire into the elementary com- position of plants, the nature of the food by which they are nour- ished, the sources from which this food is derived, and the transfor- mations it undergoes in their system. It is in vegetable digestion, or, to use a better term, in assimilation, that the essential nature of vegetation is to be sought, since it is in this process alone that min- eral, unorganized matter is converted into the tissue of plants and other forms of organized matter (1, 12-16). From this point of view, therefore, the reciprocal relations and influences of the min- eral, vegetable, and animal kingdoms may be most advantageously contemplated, and the office of plants in the general economy of the world best understood. This portion of general physiology is inti- mately connected with chemistry, and some knowledge of that sci- ence is requisite for understanding it. We are here restricted to the bare statement of the leading facts which are thought to be established, and the more important deductions which may be drawn from them. 317. While the organs of vegetation have been considered ana- tomically and morphologically, or in view of their structure and development, still the leading points of their physiology, or connected action in the life and growth of the plant, have from time to time been explained or assumed. 318. The functions of nutrition, which, in the higher animals, comprise a variety of distinct processes, are reduced to the greatest degree of simplicity in vegetables. Imbibition, assimilation, and growth essentially include the whole. 319. Plants absorb their food, entirely in a liquid or gaseous form, by imbibition, according to the law of endosmosis (40), through the178 THE FOOD AND NUTRITION OF PLANTS. walls of the cells that form the surface, principally those of the newest roots and their fibrils (133). The fluid absorbed by the roots, mingled in the cells with some previously assimilated matter they contain in solution (26, 79), is diffused by exosmosis and endos- mosis from cell to cell, rising principally in the wood (224, 230) ; and is attracted into the leaves (or to other parts of the surface of the plant exposed to the air and light) by the exhalation which takes place from them (314), and the consequent inspissation of the lated, or converted into organizable matter (79); and, thus prepared I to form vegetable tissue or any organic productflhe elaborated fluid is attracted into growing parts by endosmosis, in consequence of its consumption and condensation there, or is diffused through the newer tissues. (Jliere is no movement in plants of the nature of the cir- culation in animals.^ Even in the so-called vessels of the latex there is merely a mechanical flow from the turgid tubes towards the place where the liquid is escaping when wounded, or from a part placed under increased pressure (63). The only circulation, or directly vital movement of fluid, in vegetable tissue, is the cyclosis, or the system of currents in the layer of protoplasm in young and active cells (36) : this movement is confined to the individual cell, and can have no influence in the transference of the sap from cell to cell. Respiration is likewise a function of animals alone. What is generally so called in vegetables is connected with assimilation, and is of entirely different physiological significance, as will pres- ently be shown. None of the secretions of plants appear, like many of those of animals, to play any part, at least any essential part, in nutrition. Many, if not all of them, are purely chemical transformations of the general assimilated products of plants, — are excretions rather than secretions (88-90). 320. The appropriation of assimilated matter in vegetable growth, and the production and multiplication of cells, which make up the fabric of the plant, have already been treated of (25-34). We have now mainly to consider what the food of plants is, whence it is derived, and how it is elaborated.THEIR ELEMENTARY' CONSTITUENTS. 179 Sect. II. The Food and the Elementary Composition op Plants. S21. The Food and Ihe elementary composition of plants stand in a necessary relation to each other. Since it is not to be sup- posed that plants possess the power of creating any simple element, whatever they consist of must have been derived from ivithout. Their composition indicates their food, and vice versa. If we have learned the chemical composition of a vegetable, and also what it gives back to the soil and the air, we know consequently what it must have derived from without, that is, its food. Or, if we have ascertained what the plant takes from the soil and air, and what it returns to them, we have learned its chemical composition, namely, the difference between these two. And when we compare the na- ture and condition of the materials which the plant takes from the soil and the air with what it gives back to them, we may form a correct notion of the influence of vegetation upon the mineral king- dom. By considering the materials of which plants are composed, rve may learn what their food must necessarily contain. 322. The Constituents of Plants are of two kinds ; the earthy or in- organic, and the organic. It has been stated (93) that various earthy matters, dissolved by the water which the roots absorb, are drawn into the plant, and at length deposited in the wood, leaves, &c. These form the ashes which are left on burning a leaf or a piece of wood. Although these mineral matters are often turned to account by the plant, and some of them are necessary in the formation of certain products, (as the silex which gives needful firmness to the stalk of Wheat, and the phosphates which are found in the grain,) yet none of them are essential to simple vegetation, which maw', to a certain extent, proceed ivithout them. These materials, the presence of which is in some sort accidental, although for certain purposes essential, are distinguished as the earthy, or mineral, or inorganic constituents of plants. This class may be left entirely out of view for the present. But the analysis of any newly formed vegetable tissue, or of any part of the plant, such as a piece of wood, after the incrusting mineral matter has been chemically removed, invariably yields but three or four ele- ments. These, which are indispensable to vegetation, and make up at least from eighty-eight to ninety-nine per cent of every vege-180 THE FOOD AND NUTRITION OF PLANTS. table substance, are termed the universal, organic constituents of plants. They are Carbon, Hydrogen, Oxygen, and Nitrogen (10, 27). The proper vegetable structure, that is, the tissue itself, consists of only three of these elements, namely, carbon, hydrogen, and oxygen; while the fourth, nitrogen, is an essential constituent of the protoplasm, which plays so important a part in the formation of the cells and is an element of one class of vegetable products. 323. The Organic Constituents. These four elements must be fur- nished by the food upon which the vegetable lives ; — they must be drawn from the soil and the air ; in some cases, doubtless, from the latter source, as in Epiphytes, or Air-plants (149), but gener- ally and principally by absorption through the roots. The plant’s nourishment is wholly received either in the gaseous or the liquid form ; for the leaves can imbibe air or vapor only, and the roots are incapable of taking in particles of solid matter, however minutely di- vided (40, 133). 324. In whatever mode imbibed, evidently the main vehicle of the plant’s nourishment is water, which as a liquid or as vapor is continually in contact with its roots, and in the state of vapor always surrounds its leaves. We have seen how copiously water is taken up by the growing plant, and have formed some general idea of its amount by the quantity that is exhaled unconsumed by the leaves (313). But pure water, although indispensable, is insufficient for the nourishment of plants. It consists of oxygen and hydrogen; and therefore may furnish, and doubtless does principally furnish, these two essential elements of the vegetable structure. But it can- not supply what it does not itself contain, namely, the carbon and nitrogen which the plant also requires. 325. Yet the question arises, whether the water which the plant actually imbibes contains in fact a quantity of these remaining elements. Though pure water cannot, may not rain-water supply the needful carbon and nitrogen ? It is evident that, if the water which in such large quantities rises through the plant, and is ex- haled from its leaves, contain even a very minute quantify of these ingredients, in such a form that they may be detained when the superfluous water is exhaled, this might furnish the whole organic food of the vegetable; since the plant may condense and accumu- late the carbon and nitrogen, just as the extremely minute quantity of earthy matter which the water contains is in time largely accu- mulated in the leaves and wood.SOURCE OF THEIR ORGANIC CONSTITUENTS. 181 32G. As respects the nitrogen, nearly seventy-nine per cent of the atmosphere consists of this gas in an uncombined or free state, that is, merely mingled with oxygen. And, being soluble to some extent in water, every rain-drop that falls through the air absorbs and brings to the ground a minute quantity of it, which is therefore necessarily introduced into the plant with the water which the roots imbibe. This accounts for the free nitrogen which is always pres- ent in plants. 327. The plant also receives nitrogen in the form of ammonia (or hartshorn), a compound of hydrogen and nitrogen, which is always produced when any animal and almost any vegetable sub- stance decays, and which, being very volatile, continually rises into the air from these and other sources. Besides, it appears to be formed in the atmosphere, through electrical action in thunder-storms (in the form of nitrate of ammonia). The extreme solubility of am- monia and all its compounds prevents its accumulation in the atmos- phere, from which it is greedily absorbed by aqueous vapor, and brought down to the ground by rain. That the roots actually ab- sorb it may be inferred from the familiar facts, that plants grow most luxuriantly when the soil is supplied with substances which yield much ammonia, such as animal manures ; and that ammonia may be detected in the juices of almost all plants. That the am- monia in the air, and the nitre almost everywhere formed in a fertile soil, and not the free nitrogen of the atmosphere, take the principal part in the formation of the protoplasm and other quaternary ele- ments of plants, is demonstrated by Boussingault’s experiments, , showing that a seedling from which all nitrogen is excluded except " the free nitrogen of the air, as it vegetates does not increase the amount of azotized matter it originally had in the seed, but dimin- ishes it.* Rain-water, therefore, contains the third element of vegetation, namely, nitrogen, both in a separate form and in that of ammonia, &c. 328. The source of the remaining constituent, carbon, is still to be sought. Of this element plants must require a copious supply, since it forms much the largest portion of their bulk. If the carbon of a leaf or of a piece of wood be obtained separate from the other organic elements, — which may be done by charring, that is, by heating it out of contact with the air, so as to drive off the oxygen, # Comptes Rendus, November 28, 1853, and Ann. Sci. Naturelles, ser. 4, Yol. 1 & 2 (1854); also Vol. 7 (1857), showing the part which nitre plays. 16182 THE FOOD AND NUTRITION OF n.ANTS. hydrogen, and carbon, — although a small part of the carbon is necessarily lost in the operation, yet ivhat remains perfectly pre- serves the shape of the original body, even to that of its most delicate cells and vessels. With the exception of the ashes, this consists of carbon, or charcoal, amounting to from forty to sixty per cent, by weight, of the original material. Carbon is itself a solid, absolutely insoluble in water, and therefore incapable of as- sumption by the plant. The chief, if not the only, fluid compound of carbon which is naturally presented to the plant, is that of car- bonic acid gas, which consists of carbon united with oxygen. This gas makes up on the average one 2500th of the bulk of the at- mosphere ; from which it may be directly absorbed by the leaves. But, being freely soluble in water up to a certain point, it must also be carried down by the rain and imbibed by the roots. The car- bonic acid of the atmosphere is therefore the great source of carbon for vegetation. 329. It appears, then, that the atmosphere—-considering water in the state of vapor to form a component part of it — contains all the essential materials for the growth of vegetables, and in the form best adapted to their use, namely, in the fluid state. It furnishes water, which is not only food itself, inasmuch as it supplies oxygen and hydrogen, but is likewise the vehicle of the others, conveying to the roots what it has gathered from the air, namely, the requisite supply of nitrogen, either as such or in the form of ammonia, and of carbon in the form of carbonic acid. 330. These essential elements, the whole proper food of plants, may be absorbed by the leaves directly from the air, in the state of gas or vapor. Doubtless most plants actually lake in no small part of their food in this way. Drooping foliage may be revived by sprinkling with water, or by exposure to a moist atmosphere. A vigorous branch of the common Live-forever (Sedum Telephium), or of many similar plants, it is well known, will live and grow for a whole season when pinned to a dry and bare wall; and the Epi- phytes, or Air-plants (149), as they are aptly called, must derive their whole sustenance immediately from the air ; for they have no connection with the ground. That leaves absorb carbonic acid directly from the air is readily shown (348). 331. But, as a general statement, it may be said that plants, al- though they derive their food from the air, receive it mainly through their roots. The aqueous vapor, condensed into rain or dew, andSOURCE OF THEIR ORGANIC CONSTITUENTS. 183 bringing with it to the ground a portion of carbonic acid, and of nitrogen or ammonia, &c., supplies the appropriate food of the plant to the rootlets (sometimes in a liquid, but also much of it in a gaseous form). Imbibed by these, it is conveyed through the stem and into the leaves, where the superfluous water is restored to the atmosphere by exhalation* while the residue is converted into the proper nour- ishment and substance of the vegetable. S32. The atmosphere is therefore the great storehouse from which vegetables derive their nourishment; and it might be clearlyj shown that all the constituents of plants, excepting the small earthy portion that many can do without, have at some period formed a part of the atmosphere. The vegetable kingdom represents an amount of matter, which plants have withdrawn from the air, organ- ized, and confined for a time to the surface. 333. Does it therefore follow, that the soil merely serves as a foothold to plants, and that all vegetables obtain their whole nour- ishment directly from the atmosphere ? This must have been the case with the first plants that grew, when no vegetable or animal matter existed in the soil; and no less so with the first vegetation that covers small volcanic islands raised in our own times from the sea, or the surface of lava thrown from ordinary volcanoes. No vegetable matter is brought to these perfectly sterile mineral soils, except the minute portion contained in the seeds wafted thither by winds or waves. And yet in time a vast quantity is produced, which is represented not only by the existing vegetation, but by the mould that the decay of previous generations has imparted to the soil. We arrive at the same result by the simple experiment of causing a * The water exhaled may be again absorbed by the roots, laden with a new supply of the other elements from the air, again exhaled, and so on; as is beautifully illustrated by the cultivation of plants in closed Ward cases, where plants are seen to flourish for a long time with a very limited supply of water, every particle of which (except the small portion actually consumed by the plants) must pass repeatedly through this circulation. This vegetable micro- cosm well exhibits the actual relations of water, &c. to vegetation on a large' scale in nature; where the water is alternately and repeatedly raised by evapo- ration and recondcnsed to such extent that what actually falls in rain is esti- mated to be re-evaporated and rained down (on an average throughout the world) ten or fifteen times in the course of a year. In this way the atmosphere is repeatedly washed by the rain ; and those vapors washed out which else by their accumulation would prove injurious to men and animals, and conveyed to the roots of plants, which they are especially adapted to nourish.184 TIIE FOOD AN1) NUTRITION OF PLANTS. seed of known weight to germinate on powdered flints, or on a soil which has been heated to redness, and watering it with rain-water alone. When the young plant has attained all the development it is capable of under these circumstances, it will be found to weigh (after due allowance for the silex it may have taken up) perhaps fifty or one hundred times as much as the original seed. There can be no question as to the source of this vegetable matter in all these cases. The requisite materials exist in the air. Plants possess the peculiar faculty of drawing them from the air. The air must have furnished the whole. This conclusion is amply confirmed by a great variety of familiar facts ; such as the continued accumulation of vegetable mat- ter in peat-bogs, and of mould in neglected fields, in old forests, and generally wherever vegetation is undisturbed. Since this rich mould, instead of diminishing, regularly increases with the age of the forest and the luxuriance of vegetation, the trees must have drawn from the air, not only the vast amount of carbon, &c. that is V stored up in their trunks, but an additional quantity which is im- / parted to the soil in the annual fall of leaves, &c. 834. Still it by no means follows that each plant draws all its nourishment directly from the air. This unquestionably happens in some of the special cases just mentioned; with Air-plants, and with those that first vegetate on volcanic earth, bare rocks, naked walls, or pure sand. But it is particularly to be remarked, that only certain tribes of plants will continue to live under such cir- cumstances, and that none of the vegetables most useful as food for man or the higher animals will thus thrive and come to matu- rity. In nature, the races of plants that will grow at the entire expense of the air, such as Lichens, Mosses, Ferns, and certain tribes of succulent Flowering plants, gradually form a soil of vege- table mould during their life, which they increase in their decay; (and the successive generations live more vigorously upon the in- heritance, being supported partly upon what they draw from the air, and partly upon the ancestral accumulation of vegetable mould. Thus, each generation may enrich the soil, even when consisting of plants that draw largely upon vegetable matter thus accumulated; for these annually restore a, portion by their dead leaves, &c., and when they die they may bequeath to the soil, not only all that they took from it, but. all that they drew from the air. It is in this way that the lower tribes and so-called useless plants create a soil, which will in time support the higher plants, of immediate importance toSOURCE OF THEIR ORGANIC CONSTITUENTS. 185 man and the higher animals, but which could never grow and per- fect their fruit, if left, like their humble but indispensable predeces- sors, to derive an unaided subsistence directly from the inorganic world. While it is strictly true, therefore, that all the organic ele- ments have been originally derived from the air, it is not true that what is contained in almost any given plant, or in any one crop, is immediately drawn from this source. A part of it is thus supplied, but in proportions varying greatly in different species and under different circumstances. Undisturbed vegetation consequently tends always to enrich the soil. But in agriculture the crop is ordinarily removed from the land, and with it not only what it has taken from the earth, but also what it has drawn from the air; and the soil is i accordingly impoverished. Hence the farmer finds it necessary to follow the example of nature, and to restore to the land, in the form of manure, an amount substantially equivalent to what he takes away. 335. The mode in which vegetable mould is turned to account by growing plants has not yet been sufficiently investigated. Ac- cording to Liebig, the decaying vegetable matter is not employed until it has been resolved into its original inorganic elements, namely, into water, carbonic acid, ammonia, &c.; which are imbibed by the roots both directly in the gaseous state, and when taken up by the water as it percolates through the soil.* Others suppose that a portion of the food which plants derive from decaying vegetable matter may consist of soluble, still organic compounds. The econ- omy of the greenless parasitic plants (152) is adduced in confirma- tion of this view : but these are nourished by the foster plant just as its own flowers are nourished. Decisive evidence to the point is furnished by Fungi, the greater part of which live upon decaying organic matter, and have not the power of forming organizablc pfo- * While it may be rightly said, that the proportion of carbonic acid in the atmosphere is too minute directly to supply ordinary vegetation, especially that of esculent plants, with sufficient carbon, this cannot be said of the air contained in the pores and crevices of the soil, at least in any fertile soil. This air in the soil contains a far larger proportion of carbonic acid than the atmos- phere above; the excess being derived partly by direct absorption or by the action of rain, and in an enriched soil more largely from the decay of the mate- rials of former generations of plants. In a recently manured soil, the carbonic acid ordinarily amounts even to 10 or 20 per cent. See Boussingault and Lewy, in Ann. Sci. Nat. ser. 3, Vol. 19, p. 13. 16*186 THE FOOD AND NUTRITION OF PLANTS. ducts from inorganic materials ; and there is reason to think, that some Phsenogamous plants (of which our Monotropa, or Indian Pipe is one) are nourished in this way. 336. The Earthy Constituents. The mineral substances which form the inorganic constituents of plants (322) are furnished by the soil, and are primarily derived from the slow disintegration and decom- position of the rocks and earths that compose it.* These are dis- solved, for the most part in very minute proportions, in the water which percolates the soil, (aided, as to the more insoluble earthy salts, by the carbonic acid which this water contains,) and with this water are taken up by the roots. However minute their proportion in the water which the roots imbibe, the plant concentrates and accumulates them, by the exhalation of the water from the leaves, until they amount to an appreciable quantity, often to a pretty large percentage, of the solid matter of the vegetable. As might be ex- pected (312), the leaves contain a much larger amount of ashes, or earthy matter, than the wood, and herbaceous plants more than trees, in proportion to their weight when dry.f 337. The ashes left after combustion are mostly composed of the “ alkaline chlorides, with the bases of potash and soda, earthy and metallic phosphates, caustic or carbonate of lime and magnesia, silica, and oxides of iron and of manganese. Several other sub- stances are also met with there, but in quantities so small that they may be neglected.” Different species growing in the same soil appear to take in some portion of all such materials as are natu- * According to Liebig, the quantity of potash contained in a layer of soil formed by the disintegration of 40,000 square feet of the following rocks, &c., to the depth of twenty inches, is as follows. This quantity of Felspar (a large component of granite, &c.) contains . . . 1,152,000 lbs. Clinkstone, ..... from 200,000 to 400,000 “ Basalt, . . . “ 47,500 “ 75,000 « Clay-slate, 100,000 “ 200,000 “ Loam, . . . . . “ 87,000 “ 300,000 “ The silex yielded to the soil hy the gradual decomposition of granite and other rocks is in the form of a silicate of potash or other alkali, which, though insoluble in pure water, is slowly acted upon and dissolved by the united action of water and carbonic acid, or more largely by water impregnated with carbon- ate of potash, which is abundantly liberated during the natural decomposition of these rocks. t The subjoined results, selected from Boussingault, exhibit in a tabular form the relative quantities of organic and inorganic constituents in several kinds ofTHEIR EARTHY CONSTITUENTS. 187 rally presented to them in solution, but not, however, in the same proportions, nor in proportion to the relative solubility of these several substances ; while, on the other hand, the same species in different localities, and also each of its particular parts or organs, contains, or tends to contain, the same mineral constituents in nearly the same proportion. One base, however, is often substituted for another, equivalent for equivalent, as magnesia for lime, soda for potash. The roots, therefore, appear to have a certain power of selection in respect to these mineral materials. Nor is it a valid objection to this view, that they absorb poisons which destroy them. These are either organic products, such as opium ; or else are cor- rosive substances, such as sulphate of copper, which disorganize the rootlets. For mutilated roots or stems absorb all dissolved materials of the proper density that are presented to them, not only in much larger quantity (so long as the cut is fresh) than do uninjured root- lets, but almost indifferently, and in the same proportion that they absorb the water they are dissolved in. 338. In the ashes, only the salts which resist the action of heat, such as the phosphates, sulphates, and hydrochlorates, arc in the state in which they existed in the plant itself. A great part of the bases were combined with organic acfds, formed in the plant, and most largely with the oxalic (8G) : these compounds are by incinera- tion, or by exposure to the air, principally converted into carbonates. 339. It being indispensable to its well-being that a plant should find in the soil such mineral matters as are necessary to its growth, we perceive why various species will only flourish in particular soils or situations ; why plants which take up common salt, &c. are re- stricted to the sea-shore and to the vicinity of salt-springs ; why herbage, compared, in several cases, with the root or grain. The water was previously driven off by thorough drying. Leaves of Man- gel-Wurzel. Root of Mangel- Wurzel. 1 Potato-tops. Potatoes. Pea-straw. Peas. Clover-hay. J cJ 0) t 13 01 ■3 fcj Carbon, 38.10 42 75 44.80 43.72 45.80 46.06 47.53 48-48 46.10 Hydrogen, 5.10 5.77 5.10 6.00 5.00 6.09 4.69 5.41 5.80 Oxygen, Nitrogen, 30.80 43.58 30.50 44.88 35.57 40.53 37.96 38.79 43 40 4.50 1.66 2.30 1.50 2.31 4.18 2 06 0.35 2.27 Ashes, 21.50 6.24 17.30 3 90 11.32 3.14 7.76 6.97 2.43 100.00 100.00 100.00 100 00 i oo.oo 100.00 i no 100.00 100.00 188 THE FOOD AND NUTRITION OF PLANTS. numerous weeds which grow chiefly around dwellings, and follow the footsteps of man and the domestic animals, flourish only in a soil abounding in nitrates (their ashes containing a notable quantity either of nitrate of potash or of lime) ; why the Vine requires alka- line manures, to replace the large amount of tartrate of potash which the grapes contain ; and why Pines and Firs, the ashes of which contain very little alkali, will thrive in thin or sterile soils, while the Beech, Maple, Elm, &c., abounding with potash, are only found in strong and fertile land. 340. Where vegetation is undisturbed by man, all these needful earthy materials, which are drawn from the soil during the growth of the herbage or forest, are in time restored to it by its decay, in an equally soluble form, along with organic matter which the vegetation has formed from the air. But in cultivation, the prod- uce is carried away, and with it the materials which have been slowly yielded by the soil. “ A medium crop of Wheat takes from one acre of ground about 12 pounds, a crop of Beans about 20 pounds, and a crop of Beets about 11 pounds, of phosphoric acid, besides a very large quantity of potash and soda. It is obvious that such a process tends continually to exhaust arable land of the mineral substances useful to'vegetation which it contains, and that a time must come, when, without supplies of such mineral matters, the land would become unproductive from their abstraction..........In the neighborhood of large and populous towns, for instance, where the interest of the farmer and market-gardener is to send the largest possible quantity of produce to market, consuming the least possible quantity on the spot, the want of saline principles in the soil would very soon be felt, were it not that for every wagon-load of greens and carrots, fruit and potatoes, corn and straw, that finds its way into the city, a wagon-load of dung, containing each and every one of these principles locked up in the several crops, is returned to the land, and proves enough, and often more than enough, to replace all that has been carried away from it.” * The loss must either be made up by such equivalent return, or the land must lie fallow from * Boussingault, Economic Rurale : from tlio Engl. Trans., p. 493. Further : “ It may he inferred that, in the most frequent case, namely, that of arable lands not sufficiently rich to do without manure, there can be no continuous [independent] cultivation without annexation of meadow ; in other words, one part of the farm must yield crops without consuming manure, so that this may replace the alkaline and earthy salts which are constantly withdrawn by sue-THEIR EARTHY CONSTITUENTS. 189 time to time until these soluble substances are restored by further disintegration of the materials of the soil: or meanwhile the more exhausting crops may he alternated with those that take least from the soil and most from the air; or with one which, like clover, although it takes up 77 pounds of alkali per acre, may be consumed on the field, so as to restore most of this alkali in the manure for the succeeding crop. 341. It has been asserted that the advantage of preceding a wheat crop by one of Leguminous plants (such as Peas, Clover, Lucerne, &c.), or of roots or tubers, is owing to the fact, that these leave the phosphates, &c. nearly untouched for the wheat which is to follow, and which largely abstracts them. The results of Bous- singault’s experiments and analyses show that these products are far from having the deficiency of phosphates which was alleged. “ For example, beans and haricots take 20 and 13.7 pounds of phosphoric acid from every acre of land; potatoes and beet-root take 11 and 12.8 pounds of that acid, exactly what is found in a crop of wheat. Trefoil is equally rich in phosphates with the sheavos of corn that have gone before it.” * His further re- cessive harvests from another part. Lands enriched by rivers alone permit of a total and continued export of their produce without exhaustion. Such are the fields fertilized by the inundations of the Nile; and it is difficult to form an idea of the prodigious quantities of phosphoric acid, magnesia, and potash, which, in a succession of ages, have passed out of Egypt with her incessant exports of corn.” — p. 503. * Boussingault, l. c-., p. 497. — Subjoined is a table, from the same work, of the percentage of Mineral Substances taken up from the soil by various plants grown at Bechelbronn. Substances which yielded the Ashes. •1 0 1 CP >• Sulphuric. 2. .2 'E o ,4 Oj o S3 Cu Chlorine. Lime. .2 '1 S Potash. Soda. Silica. Oxide pf Iron, Alumina, &c. Charcoal, Moist- ure, and Loss. Potatoes, 13.4 7.1 11.3 27 1.8 5.4 51.5 traces 5.6 0.5- 07 Mangel-Wurzel, 16.1 1.6 6.1 5.2 7.0 4.4 39.0 6.0 8.0 2.5 4.2 Turnips, 14 0 10.9 6.0 2.9 10.9 4.3 33 7 4.1 6.4 1.2 5.5 Potato-tops, 11.0 22 10.8 1.6 2.3 1.8 44.5 traces 13 0 5.2 7 6 Wheat, 0.0 1.0 47.0 traces 2.9 15.9 29.5 traces 1.3 0.0 2.4 Wheat-straw, 00 1.0 3.1 0.6 8.5 50 9.2 0.3 67.6 1.0* 3.7 Oats, 1.7 1.0 14.9 0.5 3.7 7.7 12.9 0.0 53.3 1.3 3.0- Oat-straw, 3.2 4.1 3.0 4.7 83 28 24.5 4 4 40.0 2.1 29 Clover, 25.0 2.5 6.3 2.6 24 6 6.3 26 6 05 5.3 OS 0.0 Peas, 0.5 4.7 30.1 i.i 10 1 11.9 35.3 2.5 1.5 traces 2.3 French beans, 3.3 1.3 26 8 0.1 5.8 115 49.1 00 1.0 traces 1.1 Horse beans, 10 1.6 34.2 0.7 5.1 8.6 45.2 00 05 traces 3 1>190 THE FOOD AND NUTRITION OF PLANTS. searches seem to show that these crops exhaust the soil less than the cereal grains, in part at least, on account of the large quantity of organic matter, rich in nitrogen, which they leave to be incor- porated with the soil. The theory of rotation in crops, founded by De Candolle on the assumption that excretions from the roots of a plant accumulate in the soil until in time they become injurious to that crop, but furnish appropriate food for a different species, is entirely abandoned as an explanation ; and even the fact that such excretions are formed, at least to any considerable extent, is not made out. That they could accumulate and remain in the soil without undergoing decomposition is apparently impossible. Sect. III. Assimilation, or Vegetable Digestion, and its Results. 342. Wf. have reached the conclusion, that the universal food of plants is rain-water, which has' absorbed some carbonic acid gas and nitrogen (partly in the form of ammonia or of other compounds) from the air, or dissolved them from the remains of former vegeta- tion in the soil, w'hence it has also taken up a variable (yet more or less essential) quantity of earthy matter. 343. This fluid, imbibed by the roots, and carried upwards through the stem, receives the name of sap or crude sap (79). Upon its introduction into the plant, this is at once mingled with some elaborated sap or soluble organized matter it meets with; thus becoming sweet in the Maple, &c., and acquiring different sensible properties in different species. This latter is already elab- orated food, and may therefore be immediately employed in vegeta- ble growth. But the crude sap itself is merely raw material, unor- ganized or mineral matter, as yet incapable of forming a part of the living structure. Its conversion into organized matter constitutes the process of 344. Assimilation, or what, from an analogy with animal life, is usually termed Vegetable Digestion. To undergo this important change, the crude sap is attracted into the leaves, or other green parts of the plant, which constitute the apparatus of assimilation, where it is exposed to the light of the sun, under which influence alone can this change be effected. Under the influence of solar light, the fabric is itself constructed, and the chlorophyll, or greenASSIMILATION. 191 matter of plants, upon which, or in connection with which, the light exerts its wonderful action, is first developed. When plants are made to grow in insufficient light, as when potatoes throw out shoots in cellars, this green matter is not formed. When light is with- drawn, it is soon decomposed ; as we see when Celery is blanched by heaping the soil around its stems. So, also, the naturally green- less leaves of plants parasitic upon the roots or stems of other species (152) have no direct power of assimilation, but feed upon and grow at the expense of already assimilated matter. But all green parts, such as the cellular outer bark of most herbs, act upon the sap in the same manner as leaves, even supplying their places in plants which produce few or no leaves, as in the Cactus, &c. Under the influence of light, an essential preliminary step in vegetable digestion is accomplished, namely, the concentration of the crude sap by the evaporation or exhalation of the now superfluous water, the mechan- ism and consequences of which have already been considered (313). 345. We have now to consider the further agency of light in vege- table digestion itself, namely, its action in the leaf upon the concen- trated sap. Here it accomplishes two unparalleled results, which es- sentially characterize vegetation, and upon which all organized exist- ence absolutely depends (1, 16). These are,— 1st. The chemical decomposition of one or more of the substances in the sap which contain oxygen gas, and the liberation of this oxygen at the ordi- nary temperature of the air. The chemist can liberate oxygen gas from its compounds only by powerful reagents, or by great heat. 2d. The transformation of this mineral, inorganic food into organic matter, — the organized substance of living plants, and consequently of animals. These two operations, although separately stated, are in fact but different aspects of one great process. We contemplate the first, when we consider what the plant gives back to the air; the second, when we inquire what it retains as the materials of its own growth. The concentrated sap is decomposed; the portion not required in the growth of the plant is returned to the air ; and the remaining elements are at the same time rearranged, so as to form peculiar organic products. 346. The principal material given back to the air, in this pro- cess, is oxygen gas,* that element of our atmosphere which alone * A small proportion of nitrogen gas is likewise almost constantly exhaled from the leaves ; but this appears to come from the nitrogen which the water192 THE FOOD AND NUTRITION OF PLANTS. renders it fit for the breathing and life of animals. That the foliage of plants in sunshine is continually yielding oxygen gas to the sur- rounding air has been familiarly known since the. days of Ingenliouss and Priestley, and may at any moment be verified by simple experi- ment. The readiest way is, to expose a few freshly gathered leaves to the sunshine in a glass vessel filled with water, and to collect the air-bubbles which presently arise while the light falls upon them, but which cease to appear when placed in shadow. This air, when examined, proves to be free oxygen gas. In nature, diffused day- light produces this effect; but in our experiments, direct sunshine is generally necessary to show it. What is the source of this oxygen gas, which is given up to the air just in proportion to the vigor of assimilation in the leafy plant, or, in other words, to the consumption of crude sap ? 347. This will be manifest on comparing the materials with the general products of vegetation, — what the plant takes as its food, with what it makes of it, in growth. Suppose the plant is assimi- lating its food immediately into its fabric, viz. into Cellulose, or the substance of which its tissue consists (27). This matter, when in a pure state, and free from incrusting materials, has a perfectly uni- form composition in all plants. It is composed of carbon, hydrogen, and oxygen, the latter two existing in the same proportions as in water.* * It may therefore be said to consist of carbon and the ele- ments of water. These materials are necessarily furnished by the plant’s food. The mineral food of the plant, from which its fabric is made (329), is carbonic acid and water. If this be decomposed in vegetation, and the carbonic acid give up its oxygen, carbon and the elements of water remain, — the very composition of cellulose or vegetable tissue. Doubtless, then, the oxygen which is rendered to the air in vegetation comes from the carbonic acid which the plant took from the air (328). 348. This view may be confirmed by direct experiment. We imbibed by the roots had absorbed from the air (326), and which passes off un- altered from the leaves when this water is evaporated, or from nitrogen in the air which the rootlets directly absorb. In the course of vegetation, no more nitrogen is given out than what is thus taken in, and probably not so much. So that the exhalation of nitrogen may be left out of the general view of the changes which are brought about in vegetation. * Cellulose is chemically composed of 12 equivalents of Carbon, 10 of Hy- drogen, and 10 of Oxygen, viz. Ciq, Hio, Oio.ASSIMILATION. 193 have seen that many plants must, and all may, imbibe the whole or a part of their food directly from the air into their leaves (330).) All leafy plants evidently obtain a part of their carbonic acid in this I way. It is accordingly found, that when a current of carbonic acid is made slowly to traverse a glass globe containing a leafy plant ex- posed to full sunshine, some carbonic acid disappears, and an equal bulk of oxygen gas supplies its place. Now, since carbonic acid gas contains just its own bulk of oxygen, it is evident that what has thus been decomposed in the leaves has returned all its oxygen to the air. Plants take carbonic acid from the atmosphere, therefore (directly or indirectly) ; they retain its carbon; they give buck its oxygen.* 349. But cellulose, being the final, insoluble product of vegetation appropriated as tissue, can hardly be directly formed in the first in- stance. The substances from which it must originate, and which actually abound in the elaborated sap, are Dextrine or Vegetable Mucilage (79, 83), Sugar (80), &c. The first of these is probably directly produced in assimilation. Its chemical composition is the same as that of pure cellulose: it consists, not only of the same three elements, but of the same elements in exactly the same pro- portion. Dextrine, vegetable mucilage, &c. are the primary, as yet unappropriated materials of vegetable tissue, or unsolidified cellu- lose, and their production from the crude sap is attended with the evolution of the oxygen which was contained in the carbonic acid of the plant’s food, as already stated. Nor would the result in any respect be altered if Starch were directly produced. This substance is merely dextrine, which, instead of being immediately appropriated in growth, is condensed into solid grains, and in that compact and * At least, the result is as if the oxygen exhaled were all thus detached from the carbon of the carbonic acid. Just this amount is liberated, and the facts obviously point to the carbonic acid as its real source. But, on the other hand, it appears unlikely that a substance which holds oxygen with such strong affinity as carbon should yield the whole of it under these circumstances : and water is certainly decomposed, with the evolution of oxygen, in the formation of a class of vegetable products soon to be mentioned ; besides, Edwards and Colin have shown that water is directly decomposed during germination. Still, as no one supposes that the residue after the liberation of oxygen is carbon and water, but only the three elements in the proportions which would constitute them, it amounts to nearly the same thing whether we say that the oxygen of the carbonic acid, or an amount of oxygen equivalent to that of the carbonic acid, derived partly from, it and partly from the water, is liberated in such cases. y, 17194 THE FOOD AND NUTRITION OF PLANTS. temporarily insoluble form accumulated as the ready prepared ma- terials of future growth (82). Notwithstanding the difference in their properties and chemical reactions, these and other general ternary products (79) are strictly isomeric; that is, they consist of the same elements, combined in the same proportions; and physi- ologically they are merely different states of one and the same thing. Dextrine is the most soluble state, and is probably that originally formed in assimilation in the foliage: starch, amyloid (83), &e. are temporarily solidified states; and cellulose is the ultimate and usu- ally permanent insoluble condition. Accordingly, whenever the ma- terials of growth are supplied from accumulations of nourishment, as especially from the seed in germination. (123 - 125), from fleshy, roots (145), rootstocks, tubers, &c. (188-194), the starch or its! equivalent is dissolved in the sap, being spontaneously reconverted! into dextrine and sugar, and attracted in a liquid state into thoj growing parts, where, transformed into cellulose, it becomes a por- tion of the permanent vegetable fabric. 350. If, however, we suppose sugar to be a direct product of the assimilation of carbonic acid and water, the amount of oxygen gas exhaled will be just the same as before. For this has the same elementary composition as dextrine, starch, and cellulose, with the addition of one or two equivalents of w'ater according to the kind.* And when formed as a transformation of dextrine, then the latter has only to appropriate some water. In the origination of all these products, therefore, the same quantity of carbonic acid is consumed, and all its oxygen restored to the air.f It is more and more evident, * The formula for cane-sugar is Cu, Hn, On ; for grape-sugar, C12, Hu, Ou. t Since all these neutral ternary substances are identical, or nearly so, in ele- mentary composition, and since, with the same amount of carbon, derived from the decomposition of carbonic acid, the plant can form them all, it will no longer appear surprising that they should be so readily convertible into each other in the living plant, and even in the hands of the chemist. But the chemistry of organic nature exceeds the resources of science, and constantly produces trans- formations which the chemist in his laboratory is unable to effect. The latter can change starch into dextrine, and dextrine into sugar; but he cannot reverse the process, and convert sugar into dextrine, or dextrine into starch. In the plant, however, all these various transformations are continually taking place. Thus, the starch deposited in the seed of the Sugar-cane, Indian Corn, &c. is changed into sugar in germination ; and the sugar which fills the tissue of the stem at the time of flowering is rapidly carried into the flowers, where a portion is transformed into starch and again deposited in the newly-formed seeds. AndASSIMILATION. 195 therefore, that, by just so much as plants grow, they take carbonic acid from the air, they retain its carbon, and return its oxygen. 351. In the production of that modification of cellulose called Lignine (42), which abounds in wood (if this be really a simple product, and not a mixture), not only must a larger amount of car- bonic acid be decomposed, but a small portion of water also, with the liberation of its oxygen. For the composition attributed to it shows that it contains less oxygen than would suffice to convert its hydrogen into water.* * 352. The whole class of fatty substances, including the Oils, Wax, Chlorophyll (84, 88, 92), &c., contain, some of them no oxygen at all (such as caoutchouc and Pine-oil), and all of them less, oxygen than is requisite to convert their hydrogen into water. In their direct formation, if this be supposed, not only all the oxygen of the carbonic acid has been given out, but also a portion belonging to the water. If formed by a further deoxidation of neutral ternary pro- ducts, the same result is attained as respects the liberation of oxy- gen gas, but by two or more steps instead of one. The Resins, doubtless, are not direct vegetable products, but originate from the alternation and partial oxidation of the essential oils. Balsams, which exude from the bark of certain plants, are natural solutions of resins in their essential oils, as rosin, or Pine-resin, in the oil of tur- pentine. 353. An opposite class, the Vegetable Acids (86), contain more oxygen than is necessary for the conversion of their hydrogen into water, but less than the amount which exists in carbonic acid and water. Indeed, the most general vegetable acid, the oxalic (which may be formed artificially by the action of nitric acid on starch), has no hydrogen, except in the atom of water that is connected with it. Acids are sometimes formed in the leaves, as in the Sorrel, the although the chemist is unable to transform starch, sugar, &c. into cellulose, yet he readily effects the opposite change, by reconverting woody fibre, &c. (under the influence of sulphuric acid) into dextrine and sugar. The plant does the same thing in the ripening of fruits, during which a portion of tissue is often transformed into sugar. Starch-grains and cellulose can never be formed arti- ficially, because they are not merely organizable matter, but have an organic structure. * According to Payen, lignine, separated as much as possible from cellulose, consists of Carbon 53.8, Hydrogen 6.0, and Oxygen 40.2 per cent, = C35, Ha, O'jo.196 THE FOOD AND NUTRITION OF PLANTS. Grape-vine, &c., but usually in tlie fruit. If produced directly from the sap, as they may be in acid leaves, only a part of the oxygen in the carbonic acid which contributes to their formation would be ex- haled. But if formed from sugar, or any other of the general pro- ducts of the proper juice, the absorption of a portion of oxygen from the air would be required for the conversion; and this absorption takes place (at least in some cases) when fruits acquire their acidity. Even their formation by the plant, therefore, is attended by the lib- eration of oxygen gas, though in less quantity than in ordinary vege- tation. 354. There is still another class of vegetable products of uni- versal occurrence, and, although comparatively small in quantity in plants, yet of as high importance as those which constitute their permanent fabric; namely, the neutral quaternary organic com- pounds, of which nitrogen is a constituent (79). These, also, are mutually convertible bodies, related to each other as dextrine and sugar are to starch and cellulose, and playing the same part in the animal economy that the neutral ternary products do in the vege- table, i. e. forming the fabric of animals. The basis or type of these azotized products has received the name of Proteine (27) : hence they are sometimes collectively called proteine compounds. In their production from the plant’s food, the ammonia, or other azotized matter it contains, plays an essential part; and oxygen gas is restored to the air from the decomposition of all the carbonic acid concerned and of a part of the water.* 355. In living cells the proteine forms the protoplasm, or vitally active lining, which may be said to give origin to the vegetable structure, since the cellulose is deposited under its influence to form the permanent walls or fabric of the cells, as has already been explained (26-3G). When the cells have completed their growth * The chemical changes have been tabulated thus : — The materials : From which are formed the product: c. H. N. 0. C. H. N. 0. 74 of Water, 74 74 1 of Proteine, 48 36 6 14 94 of Carbonic acid, 94 188 4 of Cellulose, 48 40 40 2 of Carbonate of ;* 212 of Oxygen lib- ammonia, 2 2 6 4 erated, 212 96 76 6 266 96 76 6 266 Besides, proteine either contains or is naturally combined with a small quan- tity of sulphur and phosphorus (10).ASSIMILATION. 197 and transformation, the protoplasm abandons them, the portion which is not decomposed being constantly attracted onwards into forming and growing parts, where it incites new development. For this azotized matter has the remarkable peculiarity of inducing chemical changes in other organic products, especially .the neutral ternary bodies, causing one kind to be transformed into another, pr even the decomposition of a part into alcohol, acetic acid, and finally into carbonic acid and water (as in germination, &c.), — itself remaining the while essentially unaltered. 356. -The constant attraction of the protoplasm from the com- pleted into the forming parts of the plants explains how it is, that so small a percentage of azotized matter should be capable of playing such an all-important part in the vegetable economy. It does its work with little loss of material, and no portion of it is fixed in the tissues. At least, the little that remains in old parts is capa- ble of being washed out, showing that it forms no integral part of the fabric. This explains why the heartwood of trees yields barely a trace of nitrogen, while the sap-wood yields an appreciable amount, and the cambium-layer and all parts of recent formation, such as the buds, young shoots, and rootlets, always contain a notable proportion of it. This gives the reason, also, why sap-wood is so liable to decay (induced by the proteine), the more so in proportion to its newness 1 and the quantity of sap it contains, while the completed heart-wood is so durable. The azotized matter rapidly diminishes in the stem and herbage during flowering, while it accumulates in the forming fruit, and is finally condensed in the seeds (which have a larger per- centage than any other organ), ready to subserve the same office in the development of the embryo plant it contains.* 357. When wheat-flour, kneaded into dough, is subjected to the prolonged action of water, the starch is washed away, and a tena- cious, elastic residue, the Gluten of the flour, which gives it the capability of being raised, remains. This contains nearly all the proteine compounds of the seed, mixed with some fatty matters (which may be removed by alcohol and ether) and with a little cellulose. The azotized products constitute from eight to thirty per cent of the weight of wheat-flour: the proportion varies greatly * The cotyledons of peas and beans, according to Mr. Kigg, contain from 100 to 140 parts, and the plumule about 200 parts, of nitrogen, to 1,000 parts of carbon. 17*198 THE FOOD AND NUTRITION OF PLANTS. under different circumstances, but it is always largest when the soil is well supplied with manures that abound in nitrogen. The gluten of wheat is a mixture of four isomeric quaternary products, distin- guished by chemists under the names Fibrine (identical in nature with that which forms the muscles of animals), Albumen (of the same nature as animal albumen), Caseine (identical with the curd of milk), and Glutine. In beans and all kinds of pulse, or seeds of Legu- minous plants, the azotized matter principally occurs in the form of Legumine, which is nearly intermediate in character between albu- men and caseine. 358. Comparing now these principal products of assimilation in plants with the inorganic materials from which they must needs be formed, it may clearly be perceived that the principal result of vege- tation, as concerns the atmosphere, from which plants draw their food, consists in the withdrawal of water, of a little ammonia, and of a large proportion of carbonic acid, and of the restoration of oxygen. The latter is a constant effect of vegetation and the measure of its amount. As respects the fabric of the plant, the sole consequences of its formation upon the air are the withdrawal of a small quantity of water, and of a large amount of carbonic acid gas, and the resto- ration of the oxygen of the latter. In the formation of its azotized materials, a portion of ammonia or of some equivalent compound of nitrogen is also withdrawn. It is true, indeed, that leaves decom- pose carbonic acid only in daylight; and that they sometimes give a quantity of carbonic acid to the air in the night, especially when vegetation languishes, or even take from it a little oxygen. But this does not affect the general result, nor require any qualification of the general statement. The work simply ceases when light is withdrawn. The plant is then merely in a passive state. Yet, whenever exhalation from the leaves slowly continues in darkness, the carbonic acid which the water holds necessarily flies off with it, during the interruption to vegetation, into the atmosphere from which the plant took it. So much of the crude sap, or raw mate- rial, merely runs to waste. Furthermore, it must be remembered that the decomposition of carbonic acid in vegetation is in direct op- position to ordinary chemical affinity; or, in other words, that all organized matter is in a state corresponding to that of unstable equilibrium. Consequently, when light is withdrawn, ordinary chemical forces may perhaps to some extent resume their sway, the oxygen of the air combine with some of the newly deposited carbonINFLUENCE OF VEGETATION ON THE ATMOSPHERE. 199 to reproduce a little carbonic acid, and thus demolish a portion of the rising vegetable structure which the setting sun left, as it were, in an unfinished or unstable state. This is what actually takes place in a dead plant at all times, and whenever an herb is kept in pro- longed darkness; chemical forces, exerting their power uncontrolled, demolish the whole vegetable fabric, beginning with the chlorophyll (as we observe in blanching Celery), and at length resolve it into the carbonic acid and water from which it was formed. But this must all be placed to the account of decomposing, not of growing vegetation ; and even if it were a universal phenomenon, which is by no means the case,* would not affect the general statement, that, by so much as plants grow, they decompose carbonic acid and give its oxygen to the air ; or, in other words, purify the air. 359. Every six pounds of carbon in existing plants have withdrawn twenty-two pounds of carbonic acid gas from the atmosphere, and replaced it with sixteen pounds of oxygen gas, occupying the same bulk. To form some general conception of the extent of the influ- ence of vegetation upon the air we breathe, therefore, we should compute the quantity of carbon, or charcoal, that is contained in the * It is stated that many ordinary plants, when in full health and vigorous vegetation, impart no carbonic acid to the air during the night. — See Pepys, in Philosophical Transactions, for 1843. — Plants deteriorate the air only in their decay, and in peculiar processes, distinct from vegetation and directly the re- verse of assimilation ; as in germination, for instance, where the proteine in- duces the decomposition of a portion of the store of assimilated matter, in order that the rest may be brought into a serviceable condition. The evolution of carbonic acid by plants, therefore, when it occurs, is no part of vegetation. And it is by a false analogy that this loss which plants sustain in the night has been dignified with the name of vegetable respiration, and vegetables said to vitiate the atmosphere, just like animals, by their respiration, while they purify it by their digestion. If, indeed, this were a constant function, in any way contributing to maintain the life and health of the plant, it might be properly enough compared with the respiration of animals, which is itself a decomposing operation. But this is not the case. And herein is a characteristic difference between vegetables and animals : the tissues of the latter require constant interstitial renewal by nutrition, new particles replacing the old, which are removed and restored to the mineral world by respiration: while in plants there is no such renewal, but the fabric, once completed, remains unchanged, ceases to be nourished, and conse- quently soon loses its vitality; while new parts are continually formed farther on to take their places, to be in turn abandoned. Plants, therefore, having no decomposition and recomposition of any completed fabric, cannot properly be said to have the function of respiration.200 THE FOOD AND NUTRITION OF PLANTS. forests and herbage of the world, and add to the estimate all that exists in the soil, as vegetable mould, peat, and in other forms; all that is locked up in the vast deposits of coal (the product of the vegetation of bygone ages); and, finally, all that pertains to the whole existent animal kingdom; — and we shall have the aggregate amount of a single, though the largest, element which vegetation has withdrawn from the atmosphere. By multiplying this vast amount of carbon by sixteen, and dividing it by six, we obtain an expression of the number of pounds of oxygen gas that have in this process been supplied to the atmosphere. 360. Rightly to understand the object and consequences of this immense operation, which has been going on ever since vegetation began, it should be noted, that, so far as we know, vegetation is the only operation in nature which gives to the air free oxygen gas, that indispensable requisite to animal life. There is no other pro- vision for maintaining the supply. The prevailing chemical ten- dencies, on the contrary, take oxygen from the air. Few of the materials of the earth’s crust are saturated with it; some of them still absorb a portion from the air in the changes they undergo; and none of them give it back in the free state in which they took it, — in a state to support animal life, — by any known natural process, at least upon any considerable scale. Animals all con- sume oxygen at every moment of their life, giving to the air carbonic acid in its room; and when dead, their bodies consume a further por- tion in decomposition. Decomposing vegetable matter produces the same result. Its carbon, taking oxygen from the air, is likewise restored in the form of carbonic acid. Combustion, as in burning our fuel, amounts to precisely the same thing; it is merely rapid decay. The carbon which the trees of the forest have been for centuries gathering from the air, their prostrate decaying trunks may almost as slowly restore to the air, in the original form of carbonic acid. But if set on fire, the same result may be accom- plished in a day. All these causes conspire to rob the air of its life-sustaining oxygen. The original supply is indeed so vast, that, were there no natural compensation, centuries upon centuries would elapse before the amount of oxygen could be so much reduced, or that of carbonic acid increased, as to affect the existence of the present races of animals. But such a period would eventually arrive, were there no natural provision for the decomposition of the carbonic acid constantly poured into the air from these variousRELATIONS OF THE VEGETABLE AND ANIMAL KINGDOMS. 201 sources, and for the restoration of its oxygen. The needful com- pensation is found in the vegetable kingdom. While animals con- sume the oxygen of the air, and give back carbonic acid which is injurious to their life, this carbonic acid is the principal element of the food of vegetables, is consumed and decomposed by them, and its oxygen restored for the use of animals. Hence the perfect adap- tation of the two great kingdoms of living beings to each other; — each removing from the atmosphere what would be noxious to the other; — each yielding to the atmosphere what is essential to the continued existence of the other.* 361. The relations of simple vegetation, under this aspect, to the mineral kingdom on the one hand, and the animal kingdom on the other, are simply set forth in the first part of the diagram placed at the close of this chapter. 362. But, besides this remotely essential office in purifying the air, the vegetable kingdom renders to the animal another service so immediate, that its failure for a single year would nearly depop- ulate the earth; namely, in providing the necessary food for the whole animal kingdom. It is under this view that the great office of vegetation in the general economy of the world is to be contem- plated. Plants are the sole producers of nourishment. They alone transform mineral, chiefly atmospheric materials, they condense air, into organized matter. While they thus produce upon a vast scale, they consume or destroy comparatively little; and this never in proper vegetation, but in some special processes hereafter to be con- sidered (370). Often when they appear to consume their own pro- ducts, they only transform and transfer them, as when the starch of the potato is converted into new shoots and foliage. 363. Animals consume what vegetables produce. They them- selves produce nothing directly from the mineral world. The herbivorous animals take from vegetables the organized matter which they have produced; — a part of it they consume, and in respiration restore the materials to the atmosphere, from which * It is plain, however, that, while the animal kingdom is entirely dependent on the vegetable, the latter is independent of the former, and might have existed alone. The decaying races of plants, giving back their carbon to the air and to the soil by decay, would furnish food for their successors. And since all the carbonic acid which animals render to the air in respiration they have derived from their vegetable food, this would in time have found its way back to the air, for the use of new generations of plants, without the intervention of animals. At most, they merely expedite its return.202 THE FOOD AND NUTRITION OF PLANTS. plants derived them, in the very form in which they were taken, namely, as carbonic acid and water. The portion they accumulate in their tissues constitutes the food of carnivorous animals ; who consume and return to the air the greater part during life, and the remainder in decay after death. The atmosphere, therefore, out of which plants create nourishment, and to which animals as they con- sume return it, forms the necessary link between the animal and vegetable kingdoms, and completes the great cycle of organic exist- ence. Organized matter passes through various stages in vege- tables, through others in the herbivorous animals, and undergoes its final transformations in the carnivorous animals. Portions arc con- sumed at every stage, and restored to the mineral kingdom, to which the whole, having accomplished its revolution, finally returns. 364. Moreover, plants not only furnish all the materials of the animal fabric, but furnish each principal constituent ready formed, so that the animal has only to appropriate it. The food of animals is of two kinds j—1. that which serves to support respiration and maintain the animal heat; 2. that which is capable of forming a portion of the animal fabric, of its flesh and bones. The ternary vegetable products furnish the first, in the form of sugar, vegetable jelly, starch, oil, &c., and even cellulose; substances which, contain- ing no nitrogen, cannot form an integral part of the animal frame, but, conveyed into the blood, are decomposed in respiration; the carbon and the excess of hydrogen combining with the oxygen of the air, to which they are restored in the form of carbonic acid and water. Any portion not required by the immediate demands of res- piration is stored in the tissues in the form of fat, (which the animal may either accumulate directly from the oily and waxy matters in its vegetable food, or produce by an alteration of the starch and sugar,) as a provision for future use : a deficiency of such materials subjects the tissues themselves, or the proper supporting food, to im- mediate decomposition in respiration. The quaternary or azotized products furnish the proper materials of the animal frame, the fibrine, caseine, albumen, &c. being directly appropriated from the vegetable food to form the blood, muscles, &c.; while a slight trans- formation of them gives origin to gelatine, of which the sinews, carti- lages, and the organic part of the bones, consist. The earthy por- tion of the bones, the iron in the blood, and the saline ingredients of the animal body, are drawn from the earthy constituents (33G) of the plants upon which the animal feeds. The animal merely ap-RELATIONS OF THE THREE KINGDOMS OF NATURE. 203 propriates and accumulates these already organizable materials, changing them, it may be, little by little, as he destroys them, but rendering them all back (those of the first class through the lungs, of the second through the kidneys) finally to the earth and air, from which, and in the condition in which, the vegetable took them. 365. The general relations of vegetation to the mineral and ani- mal kingdoms are exhibited in the subjoined diagram. « & H £ P o s o G 0 1 p w w M E-i fe O 03 0 M 1 H P S P H H o g H H 03 P P P <1 O 3 5. « 5 « e u £ '5.^ •S * §*a Is a q o ci ^ ^ aT ■“Si •SS-g Sg a g*\S ggs OB o as si .© fif » 3 3s ■< C*< O O <$j tq si ■sTi c.S £ ;S i2 -M Im « 8 a A, ir o * a H 1 s 2 fl t*4 Ho204 FLOWERING AND ITS CONSEQUENCES. CHAPTER VII. OF FLOWERING AND ITS CONSEQUENCES. 366. Plants have thus far been considered only as respects their Organs of Vegetation, — those which essentially constitute the vegetable being, by which it grows, deriving its support from the surrounding air and soil, and converting these inorganic mate- rials into its own organized substance. As every additional supply of nourishment furnishes materials for the development of new branches, roots, and leaves, thus multiplying both those organs which receive food and those which assimilate it, it would seem that, apart from accidents, the increase and extension of plants would be limited only by the failure of an adequate supply of nourishment. After a certain period, however, varying in different species, but nearly con- stant in each, a change ensues, which controls this otherwise indefi- nite extent of the branches. A portion of the buds, instead of elon- gating into branches, are developed in the form of Flowers ; and nourishment which would otherwise contribute to the general in- crease of the plant, is devoted to their production, and to the matu- ration of the fruit and seeds. 367. Flowering an Exhaustive Process. Plants begin to bear flowers I at a nearly determinate period for each species ; which is dependent partly upon constitutional causes, and partly upon the requisite sup- ply of nutritive matter in their system. For, since the flower and fruit draw largely upon the powers and nourishment of the plant, while they yield nothing in return, fructification is an exhaustive process, and a due accumulation of food is requisite to sustain it.* * When the branch of a fruit-tree, which is sterile or docs not perfect its blos- soms, is ringed or girdled (by the removal of ;■ narrow ring of bark), the elab- orated juices, being arrested in their downward course, are accumulated in the branch, which is thus enabled to produce fruit abundantly; while the shoots that appear below the ring, being fed by the much weaker ascending sap, do not blossom, but push forth into leafy branches. So the flowers of most trees and shrubs that bear large or fleshy fruit are produced from lateral buds, resting directly upon the wood of the previous year, in which a quantity of nutritive matter is deposited. So, also, a seedling shoot, which would not flower for several years if left to itself, blossoms the next season when inserted as a graft into an older trunk, from whose accumulated stock it draws.FLOWERING AN EXHAUSTIVE PROCESS. 205 Annuals flower in a few weeks or months after they spring from the seed, when they have little nourishment stored up in their tissue ; and their lives are destroyed by the process (144) : biennials flower after a longer period, rapidly exhausting the nourishment accumu- lated in the root during the previous season, and then perishing (145) ; while shrubs and trees do not commence flowering until they are sufficiently established to endure it. The exhaustion con- sequent upon flowering, however, is often exhibited in fruit-trees, ) which, after producing an excessive crop (especially of late fruits, y such as apples), sometimes fail to bear the succeeding year. When the crop of one year fails, the nourishment which it would have ap- propriated accumulates, and the tree may bear more abundantly the following season, and so on alternately from year to year. 368. The actual consumption of nourishment in flowering may be shown in a variety of ways; as by the rapid disappearance of the farinaceous or saccharine store in the roots of the Carrot, Beet, &c. when they begin to flower, leaving them light, dry, and empty; and by the rapid diminution of the sugar in the stalks of the Sugar- cane and of Maize at the same period. The stalks are therefore cut for making sugar just before the flowers expand, when they | contain the greatest amount of saccharine matter. 369. The consequences of this exhaustion upon the duration of plants are further illustrated by the facility with which annuals may be changed into biennials, or their life prolonged indefinitely by preventing their flowering; while they perish whenever they bear flowers and seed, whether during the first or any succeeding year.. Thus, a common annual Larkspur has given rise to a double-flowered variety in the gardens, which bears no seed, and has therefore be- come a perennial. Cabbage-stumps, which are planted for seed, may be made to bear heads the second year by destroying the flower- shoots as they arise ; and the process may be continued from year to year, thus converting a biennial into a kind of perennial plant. The effect of flowering upon the longevity of the individual is strikingly shown by the Agave, or Century-plant, — so called because it flow- ers in our conservatories only after the lapse of a hundred, or at least a great number of years ; although, in its native sultry climate, it generally flowers when five or six years old. But whenever this occurs, the sweet juice with which it is tilled at the time (which by fermentation forms pulque, the inebriating drink of the Mexicans) is consumed at a rate answering to the astonishing rapidity with which 18206 FLOWERING AND ITS CONSEQUENCES. its huge flower-stalk shoots forth (24), and the whole plant inevita- bly perishes when the seeds have ripened. So, also, the Corypha, or Talipot-tree, a magnificent Oriental Palm, which lives to a great age and attains an imposing altitude (bearing a crown of leaves, each blade of which is often thirty feet in circumference), flowers only once ; but it then bears an enormous number of blossoms, suc- ceeded by a crop of nuts sufficient to supply a large district with seed ; and the tree perishes from the exhaustion. 370. Flowering and fruiting, then, draw largely upon the plant’s resources, while they give back nothing in return. In these opera- tions, as also in germination, vegetables act as true consumers (like animals, 363), decomposing their own products, and giving back carbonic acid and water to the air, instead of taking these materials from the air. It is in flowering that they actually consume most. In fruiting, although a large quantity of nourishment is taken from the plants, this is mostly accumulated in the fruit and seed, in a con- centrated form, for the future use of the new individual in the seed. 371. The real consumption of nourishment by the flower is shown by the action of flowers upon the air, so different from that of leaves. While the foliage withdraws carbonic acid from the air, and re- stores oxygen (346, 358), flowers take a small portion of oxygen from the air, and give back carbonic acid. While leaves, therefore, purify the air we breathe, flowers contaminate it; though, of course, only to a degree which is relatively and absolutely insignificant. This process is necessarily attended by the 372. Evolution of Heat. When carbon is consumed as fuel, and by the oxygen of the air converted into carbonic acid, an amount of heat is evolved directly proportionate to the quantity of carbon consumed, or of carbonic acid produced. Precisely the same amount is more slowly generated during the gradual decomposition of the same quantity of vegetable matter by decay, — a heat which is employed by the gardener when he makes hot-beds of tan, decay- ing leaves, and manure, — or by the breathing of animals, which maintains their elevated temperature (364). The conversion of a given amount of carbon and hydrogen into carbonic acid and water, under whatever circumstances it may take place, and whether slowly or rapidly, generates in all cases the very same amount of heat. Now, since flowers consume carbon and produce carbonic acid, acting in this respect like animals, they ought to evolve heat in proportion to that consumption. This, in fact, they do. The evolution of heatEVOLUTION OF IIEAT. 207 in blossoming was first observed by Lamarck, about seventy years ago, in the European Arum, which, just as the flowers open, “ grows hot, as if it were about to burn.” It was afterwards shown by Saus- / sure in a number of flowers, such as those of the Bignonia, Gourd, and Tuberose, and the heat was shown to be in direct proportion to the consumption of the oxygen of the air, or, in other words, of the carbon of the plant. The increase of temperature, in these cases, was measured by common instruments. But now that thermo-elec- tric apparatus affords the means of measuring variations inappre- ciable by the most delicate thermometer, the heat generated by an ordinary cluster of blossoms may be detected. The phenomenon is most striking in the case of some large tropical plants of the Arum family, where an immense number of blossoms are crowded together and muffled by a hooded leaf, or spathe (390), which confines and rever- berates the heat. In some of these, the temperature rises at times to twenty or even fifty degrees (Fahrenheit) above that of the sur- rounding air. This increase of temperature occurs daify, from the time the flowers open until they fade, but is most striking during the shedding of the pollen. At night, the temperature falls nearly to that of the surrounding air; but in the course of the morning the heat comes on, as it were like a paroxysm of fever, attaining the maximum, day after day, very nearly at the same hour of the after- noon, and gradually declining towards evening. In ordinary cases, the heat of flowering is more than counterbalanced by the vaporiza- tion of the sap and the absorption of solar heat by the foliage; so that the actual temperature of a leafy plant in summer is lower than that of the atmosphere. 373. We have remarked that the principal consumption takes place in the flower; and that a store is laid up in the fruit and seed. But much even of this store is consumed when the seed germinates; and in germination, as is seen in the malting of barley, a large amount of organic matter is decomposed into carbonic acid and water, and a proportionate quantity of heat is evolved. By a not very violent metaphor it may be said, therefore, that the fabled Phce- nix is realized in the Century-plant (369), which, after living a hun- dred years, consumes itself in producing and giving life to its off- spring, who literally rise from its ashes. 374. Plants need a Season of Rest. When plants are in luxuriant growth, rapidly pushing forth leafy branches, they are not apt to produce flower-buds. Our fruit-trees, in very moist seasons, or203 FLOWERING AND ITS CONSEQUENCES. when cultivated in too rich a soil, often grow luxuriantly, but do not blossom. The same thing is observed when our Northern fruit-trees are transported into tropical climates. On the other hand, whatever checks this continuous growth, without affecting the health of the individual, causes blossoms to appear earlier and more abundantly than they otherwise would. It is for this reason that transplanted fruit-trees incline to blossom the first season after their removal, though they may not do so again for several years. A state of com- parative rest seems needful to the transformation by which flowers are. formed. It is in autumn, or at least after the vigorous vegeta- tion of the season is over, that our trees and shrubs, and most peren- nial herbs, form the flower-buds of the ensuing year. 375. The requisite annual season of repose, which in temperate climates is attained by the lowering of the temperature in autumn and winter, is scarcely less marked in many tropical countries, where winter is unknown. But the result is there brought about, not by cold, but by heat and dryness. The Cape of Good Hope, the Canary Islands, and the southern and interior parts of California, may be taken as illustrations. In the Canaries, the growing season is from November to March, — the winter of the northern hemi- sphere ; — their winter also, as it is the coolest season, the mean temperature being 66° Fahr. But the rains fall regularly, and vegetation is active ; while in summer, from April to October, it very seldom rains, and the mean temperature is as high as 73°. During this dry season, when the scorching sun reduces the soil nearly to the dryness and consistence of brick, ordinary vegetation almost completely disappears ; and the Fig-Marigolds, Euphorbias, and other succulent plants, which, fitted to this condition of things, alone remain green, not unaptly represent the Firs and other ever- greens of high northern latitudes. The dry heat there brings about the same state of vegetable repose as cold with us. The roots and bulbs then lie dormant beneath the sunburnt crust, just as they do in our frozen soil. When the rainy season sets in, and the crust is softened by moisture, they are excited into growth under a dimin- ished temperature, just as with us by heat; and the ready-formed flower-buds are suddenly developed, clothing at once the arid waste with a profusion of blossoms (194). The vegetation of such regions consists mainly of succulents, which are able to live through the drought and exposure ; of bulbous plants, which run through their course before the drought becomes severe, then lose theirTHE INFLORESCENCE. 209 foliage, while the bud remains quiescent, safely protected under ground until the rainy season returns ; and of annuals, which make their whole growth in a few weeks, and ripen their seeds, in which state the species securely passes the arid season. 376. These considerations elucidate the process of forcing plants, and other operations of horticulture, by which we are enabled to obtain in winter the flowers and fruits of summer. The gardener accomplishes these results principally by skilful alterations of the natural period of repose. He gives the plant an artificial period of rest by dryness at the season when he cannot command cold, and then, by the influence of heat, light, and moisture, which he can always command, causes it to grow at a season when it would have been quiescent. Thus he retards or advances, at will, the periods of flooring and of rest, or in time completely inverts them. CHAPTER VIII. OF THE INFLORESCENCE. 377. Inflorescence is the term used to designate the arrangement of flowers upon the stem or branch. The flower, like the branch, is evolved from a bud. Flower-buds and leaf-buds are often so similar in appearance, that it is difficult to distinguish one from the other before their expansion. The most conspicuous parts of the flower are so obviously analogous to the leaves of a branch, that they are called in common language the leaves of the flower. Such a flower as the double Camellia appears as if composed of a rosette of white or colored leaves, resembling, except in their color and texture, the clusters of leaves which are crowded on the offsets of such plants as the Houseleek (Fig. 207). We therefore naturally regard a flower-bud as analogous to a leaf-bud; and a flower, con- sequently, as analogous to a short leafy branch. 378. This analogy is confirmed by the position which flowers oc- cupy. They appear at the same situations as ordinary buds, and at no other; that is, they occupy the extremity of the stem or branch, and the axil of the leaves (159, 165). Consequently, the arrange- 18*210 THE INFLORESCENCE. ment of the leaves governs the whole arrangement of the blossoms, as well as that of the branches. The almost endless variety of modes in which flowers are clustered upon the stem, many of them exhibiting the most graceful of natural forms, all implicitly follow the general law which has controlled the whole development of the vege- table from the beginning. We have, throughout, merely buds termi- nating the stem and branches, and buds from the axil of the leaves. 379. The simplest kind of inflorescence is, of course, that of a solitary flower, — a sin- gle flower-stalk bearing a single flower; as in Fig. 306 and Fig. 327. The flower is solitary in both these instances; but in the latter case it oc- cupies the summit of the stem, that is, it stands in the place of a terminal bud ; in the former it arises from the axil of a leaf, or represents an axillary bud. These two cases exhibit, in their great- est simplicity, the two plans of inflorescence, to one or the other of which all flower-clusters belong. 380. We begin with the second of these plans ; in which the flowers all spring from axillary buds ; while the terminal bud, de- veloping as an ordinary branch, continues the stem or axis indefi- nitely. For the stem in such case may continue to elongate, and produce a flower in the axil of every leaf, until its powers are ex- hausted (Fig. 307). Tins gives rise, therefore, to what is called 381. Indefinite or Indeterminate Inflorescence. The primary axis is here never terminated by a flower; but the secondary axes (from axillary buds) are thus terminated. The various forms of indefi- nite inflorescence which in descriptive botany are distinguished by special names, as might be expected, run into one another through intermediate gradations. In nature they are not so absolutely fixed as in our written definitions ; and whether this or that name should be used in a particular case is often a matter of fancy. The sub- joined account of the principal kinds will at the same time bring to view the connection between them. 382. The principal kinds of indefinite inflorescence which have received distinctive names are the Raceme, the Corymb, the Umbel, the Spike, the Head, the Spadix, the Catkin, and the Panicle. [FIG. 306. A flowering branch of Moneywort, Lyshnachia nummularia.INDETERMINATE INFLORESCENCE. 211 383. Before illustrating these, one or two terms, of common oc- currence, may be defined. A flower which has no stalk to support it, but which sits directly on the stem or axis it proceeds from, is said to be sessile. If raised on a stalk, this is called its Peduncle. If the whole flower-cluster is raised on a stalk, this keeps the name of peduncle, or common peduncle (Fig- A? 307, p) ; and the stalk of each particular flower, if it have any, takes the name of Pedicel or partial peduncle (p'). The portion of the general stalk along which flowers are disposed is called the axis of in- florescence, or, when covered with sessile flowers, the rhachis (backbone), and sometimes (as when thick and covered with crowded flowers) the receptacle. The leaves of a flower-cluster generally are termed Bracts. But when we wish particularly to distin- guish their sorts, those on the peduncle, or main axis, and which have a flower in their axil, take the name of Bracts (Fig. 307, b) ; and those on the pedicels or partial flower-stalks, if any, that of Bractlets or Bkacteoles (&'). The bracts are often reduced to a minute size, so as to escape ordinary notice: they very frequently fall off when the flower-bud in their axil expands, or even earlier; and sometimes, as in the greater part of the Mustard family, they altogether fail to appear. 384. A Raceme (Fig. 307, 308, 315) is that form of flower-cluster in which the flowers, each on their own footstalk or pedicel, are arranged- along a common stalk or axis of infloresence; as in the Lily of the Valley, Currant, Choke-Cherry, Barberry, &c. The lowest blossoms of a raceme are of course the oldest, and therefore open first, and the order of blossoming is ascending, from the bot- tom to the top. The summit, never being stopped by a terminal flower, may go on to grow, and often does so (as in the Snowberry, Shepherd’s Purse, &c.), producing lateral flowers one after another throughout the season. In the raceme, the axis of inflorescence is more or less elongated, and the pedicels are about equal in length. 385. A Corymb (Fig. 309, 319) is the same as a .raceme, except that the lower pedicels are elongated, so as to form a level-topped or slightly convex bunch of flowers ; as in the Hawthorn, &c. FIG. 307. A Raceme, with a general peduncle (p), pedicels {p'), bracts (6), and bractlets (&')•212 THE INFLORESCENCE. 386. An Umbel (Fig. 310) differs from a corymb only in having all the pedicels arising from the same apparent point, so as to resem- ble the rays of an umbrella; — the general peduncle, in this case, bearing several flowers without any perceptible elongation of the axis of infloresence. The Primrose and the Milkweed afford familiar examples of the simple umbel. 387. A corymb being evidently the same as a raceme with a short main axis, and an umbel the same as a corymb with a still shorter axis, it is evident that the outer flowers of an umbel or corymb correspond to the lowermost in the raceme, and that these will first expand, the blossoming pro- ceeding regularly from the base to the apex, or (which is the same thing) from the circumference to the centre. This mode of development uniformly takes place when the flowers arise from axil- lary buds ; on which account the indefi- nite mode of inflorescence is also called the centripetal. 388. In all the foregoing cases, the flowers are raised on stalks, or pedicels. "When these are wanting, or so short as not to be apparent, a Spike or Head is produced. 389. A Spike is the same as the raceme, except that the flowers are sessile ; as in the Plantain (Fig. 311) and Mullein. It is an in- FIG. 308. A raceme. 309. A corymb. 310. An umbel. FIG. $11. Young spike of Plantago major. 312. Catkin ofWhite Birch.INDETERMINATE INFLORESCENCE. 213 determinate infloresence, with the primary axis elongated, and the flowers destitute of’ pedicels or with only very short ones. Two varieties of the spike have received independent names, viz. the Spadix and the Ament. 390. A Spadix is a fleshy spike enveloped by a large bract or mod- ified leaf, called a Spatiie, as in Calla palustris (Fig. 313), the Indian Turnip (Fig. 314), and the Skunk Cabbage (Fig. 1205). 313 311 391. An Ament, or Catkin, is merely that kind of spike with scaly bracts borne by the Birch (Fig. 312), Poplar, Willow, and, as to one of the two sorts of flowers, by the Oak, Walnut, and Hickory, which are accordingly called amentaceous trees. Catkins usually fall off in one piece, after flowering or fruiting, especially sterile catkins. 392. The Head, or Capitulum, is a globular cluster of sessile flowers, like that of Clover, the Button-Bush (Fig. 320), and the balls of the Buttonwood or Plane-tree. It is a many-flowered centripetal in- florescence, in which neither the primary axis *ior the secondary axes are at all lengthened. We may view it either as an umbel without any pedicels, or as a spike with a very short axis. Gen- erally it is of the latter character, as is evident in a Clover-head, where what was first a head frequently elongates into a spike as it grows older. FIG. 313, 314. Spadix of Calla and of Arum, with the spathe. 315. A raceme of Cherry. 317. A cyme. 318. Panicle of Meadow-Grass. 319. A corymb.214 THE INFLORESCENCE. 393. The base both of the head and the umbel is frequently fur- nished with a number of imperfect leaves or bracts, crowded into a cluster or whorl, termed an Involucre. The involucre assumes a great variety of forms ; sometimes resembling a calyx ; and some- FIG. 320. Head of flowers of the Button-bush, Cephalanthus occidentalis. FIG. 321. Plant of Cornus Canadensis, with its four-leaved involucre around a cluster of small flowers. 322. A separate flower enlarged. FIG. 323. Flowering branch of Cichory, with two heads of ligulate flowers.INDETERMINATE INFLORESCENCE. 215 times (as in Cornus Florida, or the common Dogwood, and C. Cana- densis, Fig. 321) becoming petal-like, and much more showy than the blossom itself. Here it is at once distinguished from the calyx or corolla by its including a number of flowers. Sometimes, how- ever, as in the Mallow and Hibiscus, the involucre forms a kind of outer calyx to each flower. 394. The axis, or rhachis (382), of a head is called its Recep- tacle. Frequently, instead of being globular or oblong, it is flat or depressed, and dilated horizontally, so as to allow a large number of flowers to stand on its level or merely convex surface; as in the Sun- flower, Aster, Marigold, Dandelion, and Cichory (Fig. 323). Here, as in Fig. 321, a set of bracts form an involucre, surrounding the dense head of flowers. And as the involucre considerably resembles a calyx, while the outer flowers, often of a peculiar sort, are readily mistaken for petals, the head in these and similar plants was called a compound flower by the older botanists. Fig. 324 rep- resents a section through a head of such flowers in a Co- reopsis ; and Fig. 325 is a slice of the same, more enlarged, displaying some of the sepa- rate flowers. In Coreopsis, as in the Sunflower, Yarrow, &c., each blossom of the head is subtended by its bract (b) ; and the bracts in such cases are called Palece or Chaff. b 395. The Fig presents a case of very singular inflorescence FIG. 324. Vertical section of a head of flowers of a Coreopsis. FIG. 325. A slice of Fig. 324, more enlarged, with one tubular perfect flower (a) left stand- ing on the receptacle, and subtended by its bract or chaff (b); also one ligulate and neutral ray- flower (c), and part of another: d, section of bracts or leaves of the involucre.216 THE INFLORESCENCE. (Fig. 590 - 592), where the flowers apparently occupy the inside instead of the outside of the axis, being enclosed within the fleshy receptacle, which is hollow and nearly closed at the top. So that while a Sunflower, or the like, is an inflorescence imitating a blos- som, a fig is an inflorescence imitating a fruit. Indeed, it is much like a mulberry (Fig. 593) or a pine-apple, turned inside out. 396. The foregoing are all forms of simple inflorescence; the ramification not passing beyond the first step; the lateral buds being at once terminated by a single flower. But the lateral flower- stalks may themselves branch, just as ordinary branches give rise to branchlets : then the inflorescence becomes compound. If the branches of a raceme are prolonged, and bear other flowers on pedi- cels similarly arranged, a compound raceme is produced ; or if the flowers are sessile, a compound spike is formed. A corymb, the branches of which are similarly divided, forms a compound corymb; and an umbel, where the branches (often called rays) bear smaller umbels at their apex, is termed a compound um- bel ; as in the Caraway, Parsnip, and almost all the species of the family Umbelliferce, which is so named on this account. 397. For these secondary umbels, a good Eng- lish name has been employed by Dr. Darlington, that of Umbellets. Their involucre, when they have any, is distinguished from that of the principal umbel by the name of Involucel. 398. When the inflorescence is compound, it is readily seen that the different kinds of inflores- cence may be combined ; the first ramification following one plan, and the subdivision another. The combination is usually expressed by a de- scriptive phrase, as “ spikes racemose, or ra- cemed,” “ heads corymbose,” &c. The combina- tion of the raceme and the corymb or the cyme gives rise to a form of inflorescence which has a technical name, viz.: — 399. The Panicle. This is formed when the secondary axes of a raceme branch in a corymbose manner, as in most Grasses (Fig. 318, 326), or when those of a corymb divide in the manner of a raceme. And the name is applied to almost any open FIG. 326. A panicle. (Compare with Fig. 307.)DETERMINATE INFLORESCENCE. 217 and more or less elongated inflorescence which is irregularly branched twice, thrice, or a greater number of times. 400. A Thyrsus, or Thyrsc, is a compact panicle of a pyramidal, oval, or oblong outline ; such as the cluster of flowers of the Lilac and Horsechestnut, a bunch of grapes, &c. 401. Definite or Determinate Inflorescence. In this class, the flowers all represent terminal buds (380). The primary axis is directly terminated by a single flower-bud, as in Fig. 327, and its growth is of course arrested. Here we have a solitary terminal flower. Further growth can take place only by the development of secondary axes from axillary buds. These may develop at once as peduncles, or as leafy branches ; but they are in either case arrested, sooner or later, by a flower-bud, just as the primary axis was (Fig. 328). If further development ensues, it is by the production of branches of the third order, from the axils of leaves or bracts on the branches of the second order (Fig. 329) ; and so on. Hence this mode of inflo- rescence is said to be definite or determinate, in contradistinction to the indeterminate mode, already treated of, where the primary or leading axes elongate indefinitely, or merely cease to grow from the failure of nourishment, or some other extrinsic cause. The most common and most regular cases of determinate inflorescence occur in opposite-leaved plants, for obvious reasons; and such are accordingly chosen for the subjoined illustrations. But the Bose, Potentilla, and Buttercup furnish familiar examples of the kind in alternate-leaved plants. 402. The determinate mode of inflorescence assumes forms which may closely imitate those of the indeterminate kind, already de- scribed, and with which they have been confounded. When, for ex- ample, all the secondary axes connected with the inflorescence are arrested by terminal flowers, without any onward growth except FIG. 327 - 329. Diagrams of regular forms of determinate or centrifugal inflorescence. 19218 THE INFLORESCENCE. what forms their footstalks or pedicels, and these are nearly equal in length, a raceme-like inflorescence is produced, as in Fig. 330; or when the flowers have scarcely any pedicels, the spike is imitated. These are distinguished from the true raceme and spike, however, by the reverse order of development of the blossoms; the terminal one opening earliest, and the others expanding in succession from above down- wards ; while the blossoming of the raceme proceeds from below upwards. Or when, by the elongation of the lower secondary axes, a corymb is imitated, the flowers are found to expand in succession from the 0 p centre of each ramification, beginning in the centre of the cluster, while the contrary occurs in the corymb. That is, while the order in indeterminate inflorescence is centripetal (387), that of the determinate mode is centrifugal. When the determinate inflorescence as- sumes the flattish or convex form, which it more com- monly does, it has a distinctive name, viz.: — 403. The Cyme. This is a flat-topped, rounded or expanded in- florescence, whether simple or compound, of the determinate class ; of which those of the Laurustinus, Elder, Dogwood, and Hydrangea (Fig. 420) are fully developed and characteristic examples. In com- pound and compact cymes, such as those of the Laurustinus, Dogwood, &c., the leaves or bracts are usually minute, rudimentary, or abor- tive, and all the numerous flower-buds of the cluster are fully formed before any of them expand ; and the blossoming then runs through the whole cluster in a short time, commencing in the centre of the cyme, and then in the centre of each of its branches, and thence pro- ceeding centrifugally. But in the Chickweeds (Fig. 331), in Hy- pericum, and many similar plants, the successive production of the branches and the evolution of the flowers, beginning with that which arrests the growth of the primary axis, go on gradually through the whole summer, until the powers of the plant are exhausted, or until all the branchlets or peduncles are reduced to single internodes, or pedicels destitute of leaves, bracts, or bractlets, when no further de- velopment can take place. Such cases enable us to study the deter- minate inflorescence to advantage, and to follow the successive steps of the ramification by direct observation. 404. A Cymille (Cymula) is a diminutive cyme, or a branch or cluster of a compound cyme. FIG. 330. Definite infloresce~_e imitating a raceme.DETERMINATE INFLORESCENCE. 219 405. The Fascicle is a very compact cyme, with upright or ap- pressed branches ; as in the Sweet William. 406. A Glomerate is a cyme condensed into a kind of head. It is to the cyme what the head is to the corymb or umbel. 407. There are several abnormal modifications of definite inflo- rescence, arising from irregular development, or the suppression of parts, such as the non-appearance sometimes of the central flower, or often of one of the lateral branches at each division; as in the ultimate ramifications of Fig. 331, where one of the lateral pedicels is wanting. When this deviation is completely manifested, that is, when one of the side branches regularly fails, the cyme is apparently converted into a kind of one-sided raceme, and the flowers seem to expand from below upwards, or centripetally. ■ The diagram, Fig. 332, when compared with Fig. 331, explains this anomaly. The place of the axillary branch which fails to develop at each ramifica- tion is indicated by the dotted lines. Cases like this occur in several Hypericums, and in some other opposite-leaved plants. An analogous case oc- curs in many alternate-leaved plants ; where the stem, being terminated by a flower, is con- tinued by a branch from the axil of the uppermost leaf or bract; this, bearing a flower, is similarly prolonged by a secondary branch ; that by a third, and so on ; as is shown in the diagram, Fig. 333. Such forms of inflo- FIG 331. The open, progressively developed cyme of Alsine Michauxii. FIG. 332, 333. Plan of two modifications of helicoid cymes or fcuau racemes.220 THE INFLORESCENCE. rescence, which we may observe in Drosera, Sedum, and Ilounds- tongue, imitate the raceme so nearly, that they have commonly been considered as of that kind. They are distinguishable, however, by the position of the flowers opposite the leaf or bract, or at least out of its axil; while in the raceme, and in every modification of cen- tripetal inflorescence, the flowers necessarily spring from the axils. But if the bracts disappear, ns they commonly do in the Forget-me- not, &c., the true nature of the inflorescence is not readily made out. The undeveloped summit is usually circinate, or coiled in a spiral manner (Fig. 219), gradually unrolling as the flowers grow and expand, and becoming straight in fruit On account of this coiled arrangement, such cymes or false racemes are said to be helicoid, or scorpioid. 408. The cyme, raceme, head, &c., as well as the one-flowered peduncle, may arise, either at the extremity of the stem or leafy branch {terminal), or in the axil of the leaves {axillary). The case of a peduncle opposite a leaf, as in the Poke, the Grape-vine, &c., is just that illustrated in Fig. 333, except that in these cases the peduncles bear a cluster of flowers instead of a single one. The tendrils of the Vine (Fig. 161) occupy the same position, and are of the same nature. In a growing Grape-vine, it is evident that the uppermost tendril really terminates the stem; and that the latter is continued by the growth of the axillary bud, situated between the petiole and the peduncle ; the branch thus formed, assuming the direction of the main stem, and appearing to be its prolongation, throws the peduncle or tendril to the side opposite the leaf. 409. The extra-axillary peduncles of most species of Solanum, &c. are terminal peduncles, which have become lateral by the evolution of an axillary branch, with which the peduncle or the petiole is united for some distance. Such peduncles sometimes come from extra-axillary accessory buds (169). 410. In the Linden (Fig. 742) the peduncle appears to spring from the middle of a peculiar foliaceous bract. But this is rather a bractlet, inserted on the middle of the peduncle, and decurrent down to its base. 411. A peduncle which arises from the stem at or beneath the surface of the ground, as in Bloodroot, the Primrose, the so-called stemless Violets, &c., is called a radical peduncle, or a Scape. 412. A combination of the two classes of inflorescence is not un- usual, the general axis developing in one way, but the separateTIIK FLOWER. 221 flower-clusters in the other. Thus the heads of the Sunflower and of all the so-called compound flowers (394) are centripetal, the flowers expanding regularly from the margin or circumference to the centre ; while the branches that bear the heads are developed in the centrifugal mode, the central heads being earliest to come into blos- som. This is exactly reversed in all Labiatie (plants of the Mint tribe); where the stem grows on indefinitely, producing axillary clusters in the form of a general raceme or spike, which blossoms from below upwards ; while the flowers of each cluster form a cyme, and expand in the centrifugal manner. These cymes, or cymules (404), are usually close and compact, and being situated one in each axil of the opposite leaves, the two together frequently form a clus- ter which surrounds the stem, like a whorl or verticil (as in the Catnip and Horehound) : hence such flowers are often said to be whorled or verticillate, which is not really the case, as they evidently all spring from the axils of the two leaves. The apparent verticil of this kind is sometimes termed a Vf.rticillaster. 413. True whorled flowers occur only in some plants with whorled leaves, as in Iiippuris and the Water Milfoil. CHAPTER IX. OF THE FLOWER. Sect. I. Its Organs, or Component Parts. 414. Having glanced at the circumstances which attend and con- trol the production of flowers, and considered the laws which govern their arrangement, we have next to inquire what the flower is com- posed of. 415. The Flower (117) assumes an endless variety of forms in ditferent species, so that it is very difficult properly to define it. The name was earliest applied, as it is still in popular language generally applied, to the delicate and gayly colored leaves or petals,, so different from the sober green of the foliage. But the petals, and all these bright hues, are entirely wanting in many flowers, while ordinary leaves sometimes assume the brilliant coloring of the 19*222 THE FLOWER. blossom The stamens and pistils are the characteristic organs of the flower; but sometimes one or the other of these disappear from a particular flower, and both are absent from full double Roses, Camellias, &c., in which we have only a regular rosette of delicate leaves. This, however, is an unnatural state, the conse- cpience of protracted cultivation. 416. The flower consists of the organs of re- production of a Phamogamous plant (114), and their envelopes. A complete flower consists of the essential organs of reproduction (viz. stamens and pistils), surrounded by two sets of leaves or envelopes which protect them. The latter are of course exterior or lower than the former, which in the bud they enclose. 417. The Floral Envelopes, then, are of two sorts, and occupy two circles, one above or within the other. Those of the lower circle, the exterior envelope in the flower-bud, form the Calyx: they commonly exhibit the green color and have much the appear- ance of ordinary leaves. Those of the inner circle, which are commonly of a more delicate texture and brighter color, and form the most showy part of the blossom, compose the Corolla. The several parts or leaves of the corolla are called Petals : and the leaves of the calyx take the corresponding name of Sepals. One of the five sepals of the flower represented in Fig. 3.34 is separately shown in Fig. 336 ; and one of the petals in Fig. 337. The calyx and corolla, taken together, or the whole floral envelopes, whatever they may con- sist of, are sometimes called the Perianth (Perianthium or Peri- gonium). 418. The Essential Organs of the flower are likewise of two kinds, and occupy two circles or rows, one within the other. The first of FIG. 334. The complete flower of a Crassula. 335. Diagram of its cross-section in the bud, showing the relative position of its parts. The five pieces of the exterior circle are sections of the sepals ; the next, of the petals ; the third, of the stamens through their anthers ; the in- nermost, of the five pistils. FIG. 336. A sepal; 337, a petal; 338, a stamen ; and 339, a pistil from the flower repre- sented in Fig. 334.ITS ORGANS OR PARTS. 223 these, those next within the petals, are the Stamens (Fig. 338). A stamen consists of a column or stalk, called the Filament (Fig. 340, a), and of a rounded body, or case, termed the An- ther (b), filled with a powdery substance called Pol- len, which it discharges through one or more slits or openings. The older botanists had no general term for the stamens taken collectively, analogous to that of corolla for the entire whorl of petals, and of calyx for the whorl of sepals. A name has, however, recently been pro- posed for the staminate system of a flower, which it is occasionally convenient to use ; that of Andrcecium. 419. The remaining, or seed-bearing organs, which occupy the centre or summit of the flower, to whose protection and perfection all the other parts of the flower are in some way subservient, are termed the Pistils. To them collectively the name of Gynascium has been applied. One of them is separately shown in Fig. 339. This is seen more magnified and cut across in Fig. 342 ; and a dif- ferent one, longitudinally divided, so as to exhibit the whole length of its cavity, or cell, is represent- ed in Fig. 341. 420. A pistil is distinguished into three parts; namely, the Ovary (Fig. 341, a), the hollow portion at the base which con- tains the Ovules, or bodies des- tined to become seeds; the Style (b), or columnar prolongation of the apex of the ovary; and the Stigma (c), a portion of the sur- face of the style denuded of epidermis, sometimes a mere point or a small knob at the apex of the style, but often forming a single or double line running down a part of its inner face, and assum- ing a great diversity of appearance in different oia plants. FIG. 340. A stamen, with the anther (b) discharging its pollen: a, the filament. FIG. 341. Vertical section of a pistil, showing the interior of its ovary, a, to one side of which are attached numerous ovjales, d : above is the 6tyle, 6, tipped by the stigma, c. FIG. 342. A Pistil of Crassula, like that of Fig. 339, but more magnified, and cut across through the ovary, to show its cell, and the ovules it contains. At the summit of the style is seen a somewhat papillose portion, destitute of epidermis, extending a little way down the in- ner face : this is the stigma.224 THE FLOWER. 421. All the organs of the flower are situated on, or grow out of, the apex of the flower-stalk, into which they are said, in botanical lan- guage, to be inserted, and which is called the Torus, or Receptacle. This is the axis of the flower, to which the floral organs are attached (just as leaves are to the stem) ; the calyx at its very base ; the petals just within or above the calyx ; the stamens just within the petals ; and the pistils within or above the stamens (Fig. 343). 422. Such is the struct- ure of a complete and regu- lar flower ; which we take as the type, or standard of comparison. The calyx and corolla are termed pro- tecting organs. In the bud, they envelope the other parts : the calyx sometimes forms a covering even for the fruit; and tvhen it retains its leaf-like texture and color, it as- similates the sap of the plant with the evolution of oxygen gas, in the same manner as do true leaves : the corolla elaborates honey or other secretions, for the nourishment, as is supposed, of the stamens and pistils. Neither the calyx nor corolla is essential to a flower, one or both being not unfrequently wanting. The stamens and pis- tils are, however, essential organs, since both are necessary to the production of seed. But even these are not always both present in the very same flower; as will be seen when we come to notice the diverse forms which the blossom assumes, and to compare them with our pattern flower. d. c Sect. II. The Theoretical Structure or General Mor- phology of the Flower. 423. To obtain at the outset a correct idea of the flower, it is needful here to consider the relation which its organs sustain to the organs of vegetation. Taking the blossom as a whole, we have recognized, in the chapter on Inflorescence (377), the identity of flower-buds and leaf-buds as to situation, &c. Flowers, consequently, FIG. 343. Parts of the flower of a Stonecrop, Sedum ternatum, two of each sort, and the receptacle, displayed : u,, sepal: 6, petal: c, stamen : d, pistil.ITS THEORETICAL STRUCTURE. 225 are at least analogous to branches, and the leaves of the flower are analogous to ordinary leaves. 42-1. But the question which now arises is, whether the leaves of the stem and the leaves and the more peculiar organs of the flower are not homologous parts, that is, parts of the same fundamental nature, although developed in different shapes that they may sub- serve different offices in the vegetable economy ; — just as the arm of man, the fore-leg of quadrupeds, the wing-like fore-leg of the bat, the true wing of birds, and even the pectoral fin of fishes, all repre- sent one and the same organ, although developed under widely dif- ferent forms and subservient to more or less different ends. The plant continues for a considerable time to produce buds which de- velop into branches. At length it produces buds which expand into blossoms. Is there an entirely new system introduced when flowers appear ? Are the blossoms formed upon such a different plan, that the general laws of vegetation, which have sufficed for the interpre- tation of all the phenomena up to the inflorescence, are to afford no further clew ? Or, on the contrary, now that peculiar results are to be attained, are the simple and plastic organs of vegetation — the stem and leaves — developed in new and peculiar forms for the ac- complishment of these new ends ? The latter, doubtless, is the cor- rect view. The plant does not produce essentially new kinds of organs to fulfil the new conditions, but adopts and adapts the old. Notwithstanding these new conditions and the successively increas- ing difference in appearance, the fundamental laws of vegetation may be traced from the leafy branch into and through the flower. That is, the parts of the blossom’ are homologous with leaves, are leaves in other forms than that of foliage. 425. The student will have observed, that in vegetation no new organs are introduced to fulfil any particular condition, but the com- mon elements, the root, stem, and leaves, are developed in peculiar and fitting forms to subserve each special purpose. Thus, the same organ which constitutes the stem of an herb, or the trunk of a tree, we recognize in the trailing vine, or the twiner, spirally climbing other stems, in the straw of Wheat and other Grasses, in the colum- nar trunk of the Palm, in the flattened and jointed Opuntia, or Prickly Pear, and in the rounded, lump-like body of the Melon- Cactus. So, also, branches harden into spines in the Thorn, or, by an opposite change, become flexible and attenuated tendrils in the Vine, and runners in the Strawberry; or, when developed under226 THE FLOWER. ground, they assume the aspect of creeping roots, and sometimes form thickened rootstalks, as in the Calamus and Solomon’s Seal, or tubers, as in the Potato. But the type is readily seen through these disguises. They are all mere modifications of the stem. The leaves, as we have already seen, appear under a still greater variety of forms, some of them as widely different from the common type of foliage as can be imagined ; such, for example, as the thickened and obese leaves of the Mesembryanthemiims; the intense scarlet or crimson floral leaves of the Euchroma, or Painted-Cup, of the Poinsettia of our conservatories, and of several Mexican Sages; the tendrils of the Pea tribe ; the pitchers of Sarracenia (Fig. 300), and also those of Nepenthes (Fig. 301), which are leaf, tendril, and pitcher combined. The leaves also appear under very different aspects in the same individual plant, according to the purposes they are intended to subserve. The first pair of leaves, or cotyledons, when gorged with nutritive matter for the supply of the earliest wants of the embryo plant, as in the Almond, Bean, Pea, &c. (Fig. 108- 120), would seem to be peculiar organs. But in some of these cases, when they have discharged this special office in ger- mination, by yielding to the young plant the store of nourishment with which they are laden, they imperfectly assume the color and appearance of foliage ; while in other cases, as in the Convolvulus (Fig. 123) and the Maple (Fig. 104), they are green and foliaceous from the first. As the stem develops, the successive leaves vary in form or size, according to the varying vigor of vegetation. In our trees, we trace the last leaves of the season into bud-scales ; and in the returning spring we may often trace the scales of opening buds through intermediate states back again into true leaves (161). 426. The analogies of vegetation would therefore lead us to ex- pect, that in flowering the leaves would be wrought into new forms, to subserve peculiar purposes. In the chapter on Inflorescence, we have already learned that the arrangement and situation of flowers upon the stem conform to this idea. In this respect, flowers are absolutely like branches. The aspect of the floral envelopes favors the same view. We plainly discern the leaf in the calyx, and again, more delicate and refined, in the petals. In numberless in- stances, we find a regular transition from ordinary leaves into sepals, and from sepals into petals. And, while even the petals are occa- sionally green and herbaceous, the undoubted foliage sometimes assumes a delicate texture and the brightest hues (425). The per-ITS THEORETICAL STRUCTURE. 227 feet gradation of leaves or bracts into sepals is extremely common. The transition of sepals into petals is exemplified in almost every case where there are more than two rows of floral envelopes ; as in the Magnolia, and especially in the White Water-Lily, various kinds of Cactus, the Illicium, or Star-Anise of the Southern States, and the Calycanthus, or Carolina Allspice, which present several series of floral envelopes, all nearly alike in color, texture, and shape ; but how many of the innermost are to be called petals, and how the re- mainder are to be divided between sepals and bracts, is entirely a matter of arbitrary opinion. In fact, the only real difference be- tween the calyx and corolla is, that the former is the outer, and the latter an inner series of floral envelopes. Sometimes the gradation extends one step farther, and exhibits an evident transition of petals into stamens ; showing that these are of the same fundamental nature as the floral envelopes, which are manifestly traceable back to leaves. The White Water-Lily (Fig. 344) exhibits this latter transition, as evi- dently as it does that of sepals into petals. Here the petals occupy sev- eral whorls; and while the exterior are nearly undis- tinguishable from the calyx, the in- ner are reduced in- to organs which are neither well-formed petals nor stamens, but intermediate be- tween the two. They are merely petals of a smaller size, with their summits contracted and transformed into imperfect anthers, containing a few grains of pollen: those of the series next within are more reduced in size, and bear perfect anthers at the apex; and a still further reduction of the lower part of the petal completes the transition into stamens of ordinary appearance. 427. By regular gradations, therefore, the leaf may be traced to FIG. 344. A sepal, petals, bodies intermediate between petals and stamens, and true sta- mens, of the White Water-Lily.228 THE FLOWER. the petal and the stamen. But we could not expect to meet with intermediate states between a stamen and a pistil, except as a mon- strosity. The same organ could not fulfil such antagonistic offices. Nevertheless, stamens changing into pistils are occasionally found in monstrous blossoms. Cases of the kind are not very rare in Wil- lows, where anthers are found either half changed or else perfectly transformed into pistils, and bearing ovules instead of pollen. In gardens some stamens of the common Poppy have been found changed into perfect pistils, and imperfect attempts of the kind are more frequently to be detected in the large Oriental Poppy. Two Apple-trees in Ashburnham, Massachusetts, have long been known, which annually produce flowers in which the petals are replaced by five small foliaceous bodies, resembling sepals, and in place of sta- mens there are ten separate and accessory pistils, inserted on the throat of the calyx. 428. This transformation of one organ into another is called met- amorphosis. Assuming green foliage to be the natural state of leaves, the sepals and petals are said to be transformed or metamor- phosed leaves ; and the stamens and pistils are still more metamor- phosed, losing as they ordinarily do all appearance of leaves. Still, if these organs be, as it were, leaves developed in peculiar states, under the controlling agency of a power which has overborne the ordinary forces of vegetation, they must always have a tendency to 345 316 develop in their primitive form, when the causes that govern the production of blossoms are interfered with during their formation. They may then reverse the spell, and revert into some organ below them in the series, as from stamens into petals, or pass at once into the state of ordinary leaves. That is, organs which from their position should be stamens or pistils may develop as petals or floral leaves, or else may revert at once to the state of ordinary leaves. Such cases of retrograde metamorphosis frequently occur in cultivated flowers. 429. Thus we often meet with the actual reconversion of xoliat FIG. 345. A small leaf in place of a pistil from the ceutre of a flower of the double Cherry. 346. An organ intermediate between a leaf and a pistil, from a similar ilower. FIG. 347. Leaflet of a Bryophyllum, developing buds along its margins.ITS THEORETICAL STRUCTURE. 229 should be a pistil into a leaf in the double Garden Cherry, either completely (Fig. 345), or else incompletely, so that the resulting organ (as in Fig. 346) is something intermediate between the two. The change of what should be stamens into petals is of common oc- currence in what are called doable and semi-double flowers of the gardens ; as in Eoses, Camellias, Carnations, &c. When such flow- ers have many stamens, these disappear as the supernumerary petals increase in number; and the various bodies that may be often ob- served, intermediate between perfect stamens (if any remain) and the outer row of petals, — from imperfect petals, with a small lamina tapering into a slender stalk, to those which bear a small'distorted lamina on one side and a half-formed anther on the other, — plainly reveal the nature of the transformation that has taken place. Car- ried a step farther, the pistils likewise disappear, to be replaced by a rosette of petals, as in fully double Buttercups. 430. In full double Buttercups we may often notice a tendency in the inner petals to turn green, that is, to retro- grade still farther into foli- aceous organs. And there is a monstrous state of the Strawberry blossom, well known in Europe, in which all the floral organs revert into green sepals, or imper- fect leaves. Fig. 348 ex- hibits a similar retrograde metamorphosis in a flower of the White Clover, where the calyx, pistil, &c. are still recognizable, although partially transformed into leaves. And the ovary, which has opened down one side, bears on each edge a number of small and imperfect leaves; much as the ordinary leaves, or rather leaflets, of Bryophyllum are apt to develop rudimentary tufts of leaves, or leaf-buds, on their margins (Fig. 347), which may grow into little plantlets, by which the species is often propagated. This retrograde metamorphosis of FIG. 318. A flower of the common White Clover reverting to a leafy branch ■ after Turpin. 20230 THE FLOWEll. a whole blossom into foliaceous parts has been termed chlorosis, from the green color thus assumed. 431. A somewhat different proof that the blossom is a sort of branch, and its parts leaves, is occasionally furnished by monstrous flowers in the production of a leafy branch from the centre of a flower, or of one flower out of the centre of another (as rose-buds out of roses). Here the receptacle or axis of the flower resumes the ordinary vegetative growth, as in Fig. 349, 350. In wet and warm springs, some of the flower- buds of the Pear and Apple are occasion- ally forced into vege- tation, so as com- pletely to break up the flower and change it into an ordinary leafy branch. This proves that the recep- tacle of a flower is of the nature of the stem. 432. An analogous kind of monstrosity, viz. the development of buds — either into leafy branches or into blossoms (Fig. 351)—in the axils of petals, or even of stamens or pistils, fur- nishes additional evidence that these bodies are of the nature of leaves; for, whatever bears a bud or branch in its axil must represent a leaf. 433. The irresistible conclusion from all such evidence is, that the flower is one of the forms — the ultimate form — under which branches appear; that the leaves of the stem, the leaves or petals of the flower, and even the stamens and pistils, are all forms of a common FIG. 349. Retrograde metamorphosis of a flower of the Fraxinella of the gardens, from Lindley's Theory of Horticulture ; an internode elongated just above the stamens, and bearing a whorl of green leaves. FIG. 350. A monstrous pear, prolonged into a leafy branch ; from Bonnet. FIG. 351. A flower of False Bittersweet (Celastrus scandeus), producing other flowers in the axils of the petals; from Turpin.ITS THEORETICAL STRUCTURE. 231 type, only differing in their special development. And it may be added, that in an early stage of development they all appear nearly alike. That which, under the ordinary laws of vegetation, would have developed as a leafy branch, here developes as a flower; its several organs appearing under forms, some of them slightly, and others extremely, different in aspect and in office from the foliage. But they all have a common nature and a common origin, or, in other words, are homologous parts (424). 434. Now, as we have no general name to comprehend all those organs which, as foliage, bud-scales, bracts, sepals, petals, stamens, &c., successively spring from the ascending axis or stem, having ascer- tained their essential identity, we naturally take some one of them as the type, and view the others as modifications or metamorphoses of it. The leaf is the form which earliest appears, and is the most general of all the organs of the vegetable ; it is the form which is indispensable to normal vegetation, since in it, as we have seen, as- similation is effected, and all organic matter is produced; it is the form into which all the floral organs may sometimes be traced back by numerous gradations, and to which they are liable to revert when flowering is disturbed and the vegetative forces again prevail. Hence the leaf may be properly assumed as the type or pattern, to which all the others are to be referred. When, therefore, the floral organs are called modified or metamorphosed leaves, it is not to be supposed that a petal has ever actually been a green leaf, and has subsequently assumed a more delicate texture and hue, or that sta- mens and pistils have previously existed in the state of foliage ; but only that what is fundamentally one and the same organ develops, in the progressive evolution of the plant, under each or any of these various forms. When the individual organ has developed, its destiny is fixed. 435. The theory of vegetable morphology may be expressed in other and more hypothetical or transcendental forms. We have preferred to enunciate it in the simplest and most general terms. But, under whatever particular formula expressed, its adoption has not only greatly simplified, but has thrown a flood of light over the whole of Structural Botany, and has consequently placed the whole logic of Systematic Botany upon a new and philosophical basis. Our restricted limits will not allow us to trace its historical develop- ment. Suffice it to say, that the idea of the essential identity of the floral organs and the leaves was distinctly propounded by Lin-232 THU FLOWER. nteus,* about the middle of the last century. It was newly taught by Caspar Frederic Wolff, about twenty years later, and again, after the lapse of nearly twenty years more, by the celebrated Goethe, who was entirely ignorant, as were his scientific contemporaries, of what Linnteus and Wolff had Written on the subject. Goethe’s curious and really scientific treatise was as completely forgotten or overlooked as the significant hints of Linnaeus had been. In ad- vance of the science of the day, and more or less encumbered with hypothetical speculations, none of these writings appear to have ex- erted any appreciable influence over the progress of the science, until it had reached a point, early in the present century, when the nearly simultaneous generalizations of several botanists, following different clews, were leading to the same conclusions. Ignorant of the writings of Goethe and Wolff, De Candolle was the first to de- velop, from an independent and original point of view, the idea of symmetry in the flower; that the plan, or type, of the blossom is regular and symmetrical, but that this symmetry is more or less in- terfered with, modified, or disguised by secondary influences, such as suppressions, alterations, or irregularities, giving rise to the greatest diversity of forms. The reason of the prevailing symmetrical ar- rangement of parts in the blossom has only recently been made apparent, in the investigation of pliyllotaxis (23G) ; from which it appears that the general arrangement of the leaves upon the stem is carried out in the flower. Sect. ni. The Symmetry of the Flower. 43G. A Symmetrical Flower is one which has an equal number of parts in each circle or whorl of organs ; as, for example, in Fig. 334, where there are five sepals, five petals, five stamens, and five pistils. It is not less symmetrical, although less simple, when there are two or more circles of the same kind of organ ; as in Sedum (Fig. 3G1), where there are two.sets of stamens, five in each; in the Barberry, where there are two or more sets of sepals, two of petals, and two of stamens, three in each set, &c. A complete flower * “ Prineipium florurn et foliorum idem est. Prineipium fremmarum et folio- rum idem cst. Gemma constat foliorum rndimentis. Periantliium sit cx con- uatis foliorum rudimentis,” etc. Plulosoplua Botanica, p. 301.ITS SYMMETRY. 233 (as already defined, 41G) is one that possesses both sorts of floral envelopes, calyx and corolla, and both essential organs, viz. stamens and pistils. 437. The simplest possible complete and symmetrical flower would be one with the ca- lyx of a single sepal, a corolla of a single petal, a single stamen, and a single pistil; as in the annexed diagram (Fig. 352), which represents the elements of a simple stem (Fig. 157), ter- minated by an equally simple flower. Each Constituent of the blossom represents a pliyton (163), with its stem part reduced to a mini- mum, and its leaf part developed in a peculiar way, according to the rank it sustains and the office it is to fulfil. That there are short inter- nodes between consecutive organs in the flower is usually apparent on minute inspection of its axis, or receptacle ; and some of them are con- spicuously prolonged in certain cases. But they are commonly so short that the organs are brought into juxtaposition, just as in a leaf- bud, and the higher or later-formed parts are interior or enclosed by the lower. 438. Perhaps the exact case of a flower at once so complete and so simple is not to be met with, the organs of the flower, or some of them, being generally multiplied. Thus we find a circle or whorl of each kind of organ, and often two or three circles, or a still larger and apparently indefinite number of parts. In fact, the floral organs usually occur in twos, threes, fours, or fives ; and the same number is apt to prevail throughout the several circles of the flower, which therefore displays a sym- metrical arrangement, or a manifest tendency towards it.1* * Terms expressive of the number of parts which compose each whorl or kind of organ — which are sometimes very convenient to use — are formed of FIG. 352 Diagram of a plant, with a distichous arrangement of the phytons, carried through the complete flower, of the simplest kind, consisting of, a, a sepal; 6, a petal; c, a stamen ; and d1 a pistil: hr is the bract or uppermost proper leaf. 20*234 THE FLOWER. 439. Having already noticed the symmetrical arrangement of the foliage (236-251), and remarked the transition of ordinary leaves into those of the blossom (426), we naturally seek to bring the two under the same general laws, and look upon each floral whorl as answering ei- ther to a cycle of alter- nate leaves with their 333 respective intemodes undeveloped, or to a pair or verticil of opposite or verticillate leaves. Thus, the simplest com- bination, where the organs are dimerous, or in twos, may be compared with the alternate two- ranked arrangement (238), the calyx, the corolla, stamens, &c. each consisting of one cycle of two ‘elements ; or else with the case of opposite leaves (250), when each set would answer to a pair of leaves. So, likewise, the organs of a trimerous flower (viz. one with its parts in threes, as in Fig. 353) may be taken either as cycles of alternate leaves of the tristichous mode (239), with the axis shortened, which would throw the parts into successive whorls of threes, or else as proper verticils of three leaves ; while those of a pentamerous or quinary flower (with the parts in fives, as in Fig. 354) would answer to the cycles of the f arrangement (240) of alternate leaves, or to proper five-leaved verticils. So the whorls of a tetra- merous flower are to be compared with the case of decussating op- the Greek numerals combined with pepos, a part. Thus a flower with only one organ of each kind, as in the diagram, Fig. 352, is monoineroits: a flower or a whorl of two organs is dimerous (Fig. 373); of three (as in Fig. 353), trimerous; of four, tetramerous (Fig. 405); of five (as in Fig. 334), pentamerous ; of six, hex- amerous; of ten, decamerous, &c. These words are often printed with figures, as 2-merous, 3-merous, 4-merous, 5-merous, and so on. FIG. 353. Parts of a symmetrical trimerous flower (Tillaea museosa): a, calyx ; b, corolla; c, stamens ; d, pistils. FIG. 354. Ideal plan of a plant, with the simple stem terminated by a symmetrical penta- merous flower; the different sets of organs separated to some distance from each other, to show the relative situation of the parts; one of each, namely, a, a sepal, b, a petal, c, a stamen, and d, a pistil, also shown, enlarged.ALTERNATION OF THE FLORAL ORGANS. 235 posite leaves, combined two by two, or with quaternary verticillate leaves (251) ; either of which would give sets of parts in fours. 440. The Alternation of the Floral Organs, We learn from obser- vation that, as a general rule, the parts of the successive circles of the flower alternate with each other. The five petals of the flower represented in Pig. 334, for ex- ample, are not opposed to the five sepals (that is, situated directly above or before them), but alter- nate with them, that is, or stand over the intervals between them; the five stamens in like manner al- ternate with the petals, and the five pistils with the stamens, as is shown in the diagram, Fig. 335. The same is the case in Fig. 353, the several organs of a flower with its parts in threes ; and in fact this is the rule, the few exceptions to which have to be separately accounted for. 441. This comports with the more usual phyllotaxis in opposite and verticillate leaves, where the successive pairs decussate, or cross each other at right angles (251), or the leaves of one verticil several- ly correspond to the intervals of that underneath, making twice as many vertical ranks as there are parts in the whorl. The alternation of the floral organs is therefore most readily explained on the assump- tion that the several circles are true decussating verticils. But the inspection of a flower-bud with the parts imbricated in aestivation (494) shows that the several members of the same set do not origi- nate exactly in the same plane. The five petals, for example, in the cross-section of the pentamerous blossom shown in Fig. 335 (and the same arrangement is still more frequently seen in the calyx), are so situated, that two are exterior in the bud, and therefore in- serted lower on the axis than the rest, the third is intermediate, and two others are entirely interior, or inserted higher than the rest. In fact, they exactly correspond with a cycle of alternate leaves of the quincuncial or five-ranked arrangement, on an extremely abbreviated axis, or on a horizontal plane, as is at once seen by comparing the ground plan, Fig. 335, with Fig. 206. Compare also Fig. 355 with Fig. 203. Also, when the parts are in fours, two are almost always exterior in the bud, and two interior. Moreover, whenever the floral envelopes, or the stamens or pistils, are more numerous, so as to occupy several rows, the spiral disposition is the more manifest. It is most natural, accordingly, to assume that the calyx, corolla, FIG. 355. Cross-section of the flower-bud of Fig. 353, to show the alternation of parts.236 THE FLOWER. stamens, &c. of a pentamerous flower are each a depressed spiral or cycle of the § mode of phyllotaxis, and those of the trimerous flower are similar spirals of the 4 mode. But then the parts of the suc- cessive cycles should be superposed, or placed directly before each other on the depressed axis, as leaves tire ; whereas, on the contrary, they almost always alternate with each other in the flower. 442. To reconcile this alternation with the laws of phyllotaxis in alternate leaves, Prof. Adrien de Jussieu has advanced an ingenious hypothesis. He assumes the T53 spiral arrangement as the basis of the flortil structure both of the trimerous and pentamerous flower, (at least when the envelopes are imbricated in the bud.) this being the one that brings the successive parts most nearly into alternation, either in threes or in fives; as will readily be observed on inspection of the tabular projection of that mode, given on page 139. The dif- ference between the position of parts in regular alternation, whether in threes or fives, and that assigned by an accurate spiral projection of the t5j mode, is very slight as respects most of the organs, and in none does the deviation exceed one thirteenth of the circumference; — a quantity which becomes nearly insignificant on an axis so small as that of most flowers. Moreover, if the interior organs of a regular and symmetrical flower were thus to originate in the bud nearly in alternation with those that precede them, they -would almost necessa- rily be crowded a little, as they develop, into the position of least pres- sure, and thus fall into these intervals with all the exactness that is actually found in nature. For in living bodies, endowed as they are with plasticity and a certain power of adaptation to circumstances, the positions assumed are not mathematically accurate ; and the effect of unequal pressure in the bud in throwing the smaller parts more or less out of their normal position may be observed in almost any irregular flower. Moreover, in all the forms of phyllotaxis from onwards, it is doubtful whether what we term vertical ranks arc exactly superposed. In tracing them upward to some extent, we perceive indications of a curviserial arrangement, where the superposition is continually approximated, but is never exactly at- tained (248). Lestibudois * has revived the older hypothesis of Jussieu, and others ; viz. that a second spiral is introduced with the petals and continued in the pistils. And Schimper and Braun im- agine a change of half the angular divergence (prosenthesis) to occur * In Annales des Sciences Naturelles, ser. 4, Vol. 2, p. 226.POSITION IN RESPECT TO THE BRACT AND AXIS. 237 in passing from one cycle to the next; — which is rather describing the anomaly in other words than explaining it. 443. Whether we regard the floral circles as decussating verticils, or as cycles of alternate leaves in some way altered as to their suc- cession, we cannot fail to discern an end attained by such arrange- ment, namely, a disposition of parts which secures the greatest econ- omy of space on an abbreviated axis, and the greatest freedom from mutual pressure. 444. Position of the Flower as respects the Axis and subtending Bract. All axillary flowers are situated between a leaf and the stem, or, which is the same thing, between a bract, and the axis of inflores- cence. These two fixed points enable us to indicate the relative position of the parts of the floral circles with precision. That part of the flower which lies next the leaf or bract from whose axil it arises is said to be anterior, or inferior (lower) : that which is dia- metrically opposite or next the axis is posterior, or superior (upper).* a a a It is important to notice the relative position of parts in this re- spect. This is shown in a proper diagram by drawing a section of the bract in its true position under the section of the flower- bud, as in Fig. 358 : the position of the axis is necessarily dia- metrically opposite, and its section is sometimes indicated by a dot or small circle. In an axillary flower with the parts in fours, one of * As if these were not terms enough, sometimes the organ, or side of the flower, which looks towards the bract, is likewise called exterior, and the organ or side next the axis, interior; but these terms should be kept to designate the relative position of the members of the floral circles in sestivation (494). FIG. 356. Diagram of a Cruciferous flower (Erysimum); a, the axis of inflorescence. (The bract is abortive in this, as in most plants of this family.) FIG. 357. Diagram of a flower of a Rhus, with the axis, a, and* the bract, 6, to show the relative position of parts. FIG. 358. Diagram of a flower of the Pulse tribe: a, the axis, and 0, the bract.238 THE FLOWER. the sepals will be anterior, one posterior, and two lateral, or right and left; as in the annexed diagram of a Cruciferous blossom (Fig. 356) ; while the petals, alternating with the sepals, consist of an anterior and a posterior pair ; and the stamens, again, stand before the sepals. An axillary flower of five parts will have either one sepal superior or posterior and two inferior or anterior (as in Rhus, Fig. 357), or else, vice versa, one inferior and two superior, as in Papilionaceous flowers (Fig. 358): in both cases the two remaining sepals are lateral. The petals will consequently stand one superior, two inferior, and two lateral, in the last-named case; and one in- ferior, two superior, and two lateral, in the former. In terminal flowers (401), the position of parts in respect to the uppermost leaves or bracts should be noted. Sect. IY. The Various Modifications of the Flower. 445. The complete and symmetrical flowers, with all their organs in the most normal state, that have now been considered, will serve as the type or pattern, with which we may compare the almost num- berless variety of forms which blossoms exhibit, and note the char- acter of the differences observed. We proceed upon the supposi- tion, that all flowers are formed upon a common plan, — a plan essentially the same as that of the stem or branch, of which the flower is a modified continuation, — so that in the flower we are to expect no organs other than those that, whatever their form and office, answer either to the axis or to the leaves ; so that the differ- ences between one flower and another are to be explained as cir- cumstantial variations of one fundamental plan, — variations for the most part analogous to those which occur in the organs of vegeta- tion themselves. Having assumed the type which represents our conception of the most complete, and at the same time the simplest flower, we apply it to all the cases which present themselves, and especially to those blossoms in which the structure and symmetry are masked or obscured; where, like the disenchanting spear of Ithuriel, its application at once reveals the real character of the most disguised and complicated forms of structure. 446. Our pattern flower consists of four circles, one of each kind of floral organ, and of' an equal number of parts, successively alternat- ing with one another. It is complete, having both calyx and corolla,ITS VAK10US MODIFICATIONS. 239 as well as stamens and pistils (416) ; symmetrical, having an equal number of parts in the successive whorls (436) ; regular, in having the different members of each circle all alike in size and shape; it has but one circle of the same kind of organs ; and, moreover, all the parts are distinct or unconnected, so as to exhibit their separate origin from the axis or receptacle of the flower. This type may be presented under either of the four numerical forms which have been illustrated. That is, its circles may consist of parts in twos (when it is binary or dimerous), threes (ternary or trimerous), fours (qua- ternary or tetramerous), or fives (quinary or pentamerous). The first of these is the least common ; the trimerous and the pentame- rous far the most so. The last is restricted to Dicotyledonous plants, where five is the prevailing number; while the trimerous flower largely prevails in Monocotyledonous plants, although by no means wanting in the Dicotyledonous class, from which Fig. 353 is taken. 447. The principal deviations from the perfectly normal or pattern flower may be classified as follows. They arise, either from, — 1st. The production of additional circles of one or more of the floral organs (regular multiplication or augmentation) ; 2d. The production of a pair or a cluster of organs where there should normally be but one, that is, the multiplication of an organ by division (abnormal multiplication, also termed deduplication or chorisis) ; 3d. The anteposition (or opposition, instead of alternation) of the parts of successive circles; 4th. The union of the members of the same circle (coalescence) ; C 5th. The union of adjacent parts of different circles (adnation) ; 6th. The unequal growth or unequal union of different parts of the same circle (irregularity) ; or, 7th. The non-production or abortion of some parts of a circle, or of one or more complete circles (suppression or abortion). 8th. To which may be added, the abnormal development of the receptacle or axis of the flower. 448. Some of these deviations interfere with the symmetrical structure of the flower ; others merely render it irregular, or dis- guise the real origin or the real number of parts. These deviations, moreover, are seldom single ; but two, three, or more of the kinds fre- quently co-exist, so as to realize almost every conceivable variation. 449. Several of these kinds of deviation may often be observed240 THE FLOWER. even in the same natural family of plants, where it cannot be doubt- ed that the blossoms are constructed upon a common plan in all the species. Even in the family Crassulaeea1, for example, where the flowers are remarkably symmetrical, and from which our pattern flowers, Fig. 334 and 353, are derived, a considerable number of these di- versities are to be met with. In Crassula, we have the completely symmetrical and simple pentamerous flower (Fig. 359, 360), viz. with a calyx of five sepals, a corolla of five petals alter- nate with the former, an androecium (418) of five stamens alternating with the petals, and a gynsecium (419) of five pistils, which are alter- nate with the stamens; and all the parts are regular and symmetrical, and also distinct and free from each other ; except that the sepals are somewhat united at the base, and the petals and stamens slightly connected with the inside of the calyx, instead of arising directly from the recep- tacle or axis, just beneath the pistils. Five is the prevailing or normal number in this family. Nevertheless, in the related genus Tiltoa, most of the species, like ours of the United States, have their parts in fours, but are otherwise similar, and one common European species has its parts in threes (Fig. 353) ; that is, one or two members are left out of each circle, which of course does not in- terfere with the symmetry of the blossom. So in the more conspic- uous genus Sedum (the Stonecrop, Live-for-ever, Orpine, &c.), some species have their parts in fives ; others in fours ; and several, like our S. ter- natum, have those of the first blossom in fives, but all the rest in fours. But Sedum also illustrates the case of reg- ular augmentation (447, 1st) in its an- droecium, which consists of twice as many stamens as there are members in the other parts ; that is, an addi- tional circle of stamens is introduced (Fig. 361), the members of which may be distinguished by being shorter or a little later than 359 FIG. 359. Flower of a Crassula. 360. Cross-section of the bud. FIG. 361. Flower of a Sedum or Stonecrop.ITS VARIOUS MODIFICATIONS. 241 those of the primary circle, and by their alternation with these, which brings them directly opposite the petals. A third genus (Rocliea) exhibits the same pentamerous and normal flower as Cras- sula, except that the contiguous edges of the petals slightly cohere about half their length, although a little force suffices to separate them: in another (Grammanthes, Fig. 362), the petals are firmly united into a tube for more than half their length, and so are the sepals likewise; illustrating the fourth of the deviations above enumerated (447). Next, the allied genus Cotyledon (Fig. 363) exhibits in the same flower both this coalescence of similar parts, and an additional circle of stamens, as in Sedum. It likewise pre- sents the next order of deviations, in the union (adnation) of the base of its stamens to the base of the corolla, out of which they ap- parently arise, as is seen in Fig. 364, where the corolla is laid open and displayed. The pistils, although ordinarily exhibiting a strong tendency to unite, are perfectly distinct in all these cases, and in- deed throughout the order, with two exceptions ; one of which is seen in Penthorum, where the five ovaries (Fig. 365) are united below into a solid body, while their summits, as well as the styles, are separate. The same plant also furnishes an example of the non- production (or suppression) of one set of organs, that of the petals; which, although said to exist in some specimens, are ordinarily want- ing altogether. Another instance of increase in the number of parts occurs in the Houseleek (Sempervivum), in which the sepals, petals, and pistils vary in different species from six to twenty, and the sta- mens from twelve to forty. 450. Some illustrations of the principal diversities of the flower, FIG. 362. Flower of Grammanthes. 363. Flower of a Cotyledon. 364. The corolla laid open, showing the two rows of stamens inserted into it. 365. The five pistils of Penthorum, united. 366. A cross-section of the same. 366 365 21242 THI! Ft O WEE. as classified above (447), may be drawn at random from different families of plants ; and most of the technical terms necessarily em- ployed in describing these modifications may be introduced, and explained, as we proceed. The multiplication of parts is usually in consequence of the 451. Augmentation of the Floral Circles. An increased number of circles or parts of all the floral organs occurs in the Magnolia family; where the floral envelopes occupy three or four rows, of three leaves in each, to be divided between the calyx and corolla, while the stamens and pistils are very numerous, and compactly arranged on the elongated receptacle. The Custard-Apple family, which is much like the last, has also two circles in the corolla, three petals in each, a great increase in the number of stamens, and, in _ our Papaw (Fig- 654), sometimes only one circle of pistils, viz. three, sometimes twice, thrice, or as many as five times that number. The Water-Lily, likewise, has all its parts augmented, the floral envelopes and the stamens especially occupying a great number of rows; and the pistils are likewise numerous, although their number is disguised by being united into one body. When the sepals, petals, or other parts of the flower are too numerous to be readily counted, or even exceed twelve, especially when the number is inconstant, as it commonly is in such eases, they are said to be indefinite ; and a flower with numerous stamens is also termed polyandrous. 452. When such multiplication of the floral circles is perfectly regular, the number of the organs so increased is a multiple of that which forms the basis of the flower ; but this could scarcely be de- termined when the numbers are large, as in the stamens of a Butter- cup, for example, nor is there much constancy when the whorls of any organ exceed three or four. The doubling or trebling of any or all the floral circles does not interfere with the symmetry of the flower; but it may obscure it (in the stamens and pistils especially), by the crowding of two or more circles of five members into what appears like one of ten, or two trimerous circles into what appears like one of six. The latter case occurs in most Endogenous plants. 453. The production of additional floral circles may account for most cases of increase of the normal number of organs, but not for all of them. It must, we think, be admitted that certain parts of the blossom are sometimes increased in number by the production of a double organ, or a pair or a group of organs which occupy the place of one ; namely, by what has been termedCHOKISIS OK DEDUPLICATION. 243 454. ChOl'isis or Deduplication. The mime dedoublement of Dunal, which has been translated deduplication, literally means unlining; the original hypothesis being, that the organs in question unline, or tend to separate into two or more layers, each having the same structure. We may employ the word deduplication, in the sense of the doubling or multiplication of the number of parts, without adopting this hypothesis as to the nature of the process, which at best can well apply only to some special cases. The word chorisis (xConvolvulus, with its tube. 539. Other pollen-grains, with their tubes, less strongly mag- nified. 540. A pollen-grain of the Evening Primrose, resting on a portion of the stigma, into which the tube emitted from one of the angles penetrates ; the opposite angle also emitting a pollen-tube. 537 538 539THE ACTION OP THE POI.LEN. 303 subsequently appears. In Gymnospermous plants (560, 573), the pollen-grains grow at the orifice of the naked ovule, and immediately penetrate its nucleus, just as they do the stigma in ordinary plants. 575. Pollen-tubes may be readily inspected under the microscope in many plants; in none more readily than in the Asclepias, or Milkweed, one of the plants in which this subject was so admirably investigated by Mr. Brown. In that family, the pollen-grains of each cell of the anther (Fig. 541) cohere in a mass ; and these pollen-masses, dislodged from their cells (Fig. 542, 543), usually by the agency of insects, and brought into proximity with the base of the stigma, protrude their tubes in great abundance. They may be seen to penetrate the base of the stigma, as in Fig. 544, and sepa- rate grains with their tubes may be detached from the mass (Fig. 546, 547); but to trace their course down the style (as in Fig. 545), and to their final destination, requires much skill in manipulation and the best means of research. 576. The formation of the pollen-tube commences in some cases almost immediately upon the applica- tion of the pollen to the stigma; in others it is not per- ceptible until after the lapse of from ten to thirty-six hours or more. The rate of the growth of the pollen-tube down the style is also very various in dif- ferent plants. In some species, a week or more elapses before they have passed through a style even of a few lines in length. In others, a few FIG. 641. A back view of a stamen of the common Milkweed (Asclepias), the appendage cut away. 542. A stamen more magnified, with the two pollen-masse3 cohering by their cau- dicles, each to a gland from the summit of the stigmatic body, to which a pollen-mass from an adjacent anther is already adherent. 643. A pair of detached pollen-masses (each from a dif- ferent anther) suspended by their caudicles from the gland. 544. Some of the pollen-masses, with their tubes penetrating the stigma (after Brown). 545. A section through the large stig- matic body and a part of the summit of one of the styles, showing the course of the pollen- tubes. 546, 547. Pollen-grains with their tubes, highly magnified. (The structure of these singular flowers will be more fully explained under the order Asclepiadacea.)304 FERTILIZATION. hours suffice for their passage through even the longest styles, such as those of Colehicum, Mirubilis or Four-o’clock, and Cereus grandi- florus. After the pollen-tubes have penetrated the stigma, the latter dries up, and its tissue begins to wither or die away, as likewise does the body of the pollen-grain, its whole contents being trans- ferred to the pollen-tube, the lower part of which may still be in a growing condition. 577. Before the pollen-tube has reached the ovule, or more com- monly even before the pollen is applied to the stigma, a cavity ap- pears in the interior of the nucleus of the ovule, near its apex. This probably results from the special growth of a particular cell, which expands into a bladder or closed sac, at length commonly oc- cupying a considerable part of the nucleus, — sometimes remaining enclosed in its tissue towards its summit or orifice, sometimes dis- placing the upper part of the nucleus entirely, or even projecting through the micropyle. This is the sac of the amnios of Mr. Brown, the embryo-sac (sac embnjonaire) of the French botanists. In this sac the embryo is formed. 578. Origin Of Hie Embryo. From the latter part of the seven- teenth century, when the relative functions of the stamens and the pistils, and something of the structure of the ovule, were demon- strated by Malpighi, Grew, &c., until about the year 1837, it was almost universally supposed that the embryo was a product of the ovule, in some way incited or fertilized- by the pollen. One writer, viz. Samuel Morland, had indeed propounded the crude hypothesis, that a pollen-grain itself, descending bodily through the style, was received into the orifice of the ovule, and became the embryo. The absurdity of this view was soon made evident. But how the pollen acted was wholly unknown until Amici, in 1823, discovered pollen- tubes, penetrating the stigma, and Brongniart, Brown, Amici himself, and Schleiden, within the ensuing twelve or fourteen years, had demonstrated their universality, and traced these slender tubes into the ovary, and even to the nucleus of the ovule. Then commenced a spirited controversy, which has only just now been brought to a close. For Professor Schleiden, in the year 1837, advanced the view that the extremity of the tube of the pollen, entering the nucleus of the ovule, there developed into the embryo, — thus anew deriving the embryo or new plant substantially from the pollen instead of the ovule. This view has recently been abandoned by its indefatigable autlior and his most able supporter, Schacht, having been thoroughly dis-ORIGIN OF THE EMBRYO. 305 proved in all points by a series of elaborate investigations made by Mirbel, Amici, Giraud, Mold, Ilofmeister, Unger, Tulasne, Ilenfrey, and Radlkofer. So that —passing by the whole history of this long discussion, and merely appending some references to the more im- portant publications upon the subject*—-we need only state here, in the most general terms, the principal facts which are now held to be established, viz.: — 579. The pollen-tube terminates on the outer surface of the embryo-sac, or sometimes, perhaps, forces its way into it. Ordina- rily its extremity becomes firmly adherent to the surface of the embryo-sac, and it appears to remain closed. Henfrey, indeed, is led to suppose that the membrane of the pollen-tube and that of the embryo-sac are absorbed at the point of contact, and that the former thus discharges its contents into the cavity of the latter; but this is merely an unproved inference, suggested by the analogy of what is now known of the process of fecundation in Cryptogamous plants. At present it appears most probable that the contents of the pollen- tube are drawn into the embryo-sac by endosmosis. However this may be, shortly after reaching the embryo-sac the pollen-tube be- comes empty, and decays or withers awny. Meanwhile the body which by its development is to give rise to the embryo appears in the embryo-sac independent of the pollen-tube. According to most investigators it generally appears before the pollen-tube has entered the ovule. (The high authority of Tulasne, however, is thus far * Schleiden first published his famous theory in "VViegmann’s Archiv, 1837, and in Acta Nova Acad. Nat. Cur., Yol. 19. It was extended and defended in his systematic works, — and especially by Schacht in Trans. Netherlands Insti- tute, 1850, in Dot. Zeitung, 1855 (transl. in Ann. Sci. Nat. of that year), in his Beitriige Anat. Phys., in his work on the microscope, of which an English translation hy Dr. Currey was published in 1855, and in the Regensberg Flora, 1855 (Ann. Sci. Nat. 1855). See also Dcecke in Dot. Zeitung, 1855 (Ann. Sci. Nat., 1. c.). On the other side of the question the most important of the recent publications, since the appearance of Mohl’s Principles of the Anatomy and Physiology of the Vegetable Cell, in the English translation (1852), and the article Ovule in the Micrographic Dictionary by Henfrey, are : Hofmeistcr, in Flora, May, 1855, and Mohl, in Bot. Zeitung, June, 1855 (both reproduced in Ann. Sci. Nat., scr. 4, Yol. 3, 1855); Tulasne, in Ann. Sci. Nat., ser. 4, Vol. 4, 1855, being the complement of his great memoir published in the same journal (scr. 3, Yol. 12, 1849) ; Radlkofer, Die Befruchtung der Phanerogamien, Leipsic, 1856 ; Henfrey, Development of the Ovule of Santalum album, &c., in Trans. Linn. Soc., Yol. 22, part 1, 1856. 26*306 FERTILIZATION. opposed to the pre-existence.) It is a small mass or globule of pro- toplasmic matter, either loose in the cavity of the embryo-sac near the place to which the pollen-tube is applied externally, or else ad- herent to the interior surface of the wall of the embryo-sac in this immediate vicinity, or sometimes separated from the embryo-sac by' an interposed globule, or by a pair of such globules. This body, the rudiment of the future embryo, has been- termed the embryonal or germinal vesicle. This is not yet a cell; for it has no covering or wall of cellulose. But it soon becomes one when a pollen-tube reaches the embryo-sac, the first known result of fertilization being that a coat of cel- lulose is deposited upon its surface. This newly-formed cell grows by cell-multiplication (33), either pro- ducing a mass of cells, as shown in Fig. 10 - 14, or else in the first place developing into an elongated cell or a thread-shaped chain of cells (the suspensor), the lower cell of which divides in all directions, forming a mass, which as it grows shapes itself into the embryo (Fig. 549 — 553), The radicle or root-end of the em- bryo is always that by which it is attached to the suspensor (which ordinarily soon disappears) or to the summit of the embryo-sac, the coty- ledons occupying the opposite ex- tremity. The radicle accordingly is always directed to the orifice or micropyle of the ovule and seed. 580'. Through the fertilization of as many germinal vesicles, two or more embryos are frequently found in the same seed, in the Orange, the Onion, and many other plants. There are generally FIG. 548. Magnified pistil of Buckwheat; the ovary and ovule divided lengthwise : some pollen on the stigmas, one grain distinctly showing its tube, which has penetrated the style, reappeared in the cavity of the ovary, entered the mouth of the orthotropous ovule (o), and reached the embryo-sac (s), near the embryonal vesicle (y).FORMATION OF THE EMBRYO. 307 two embryos in the seed of the Mistletoe ; and there is usually a plurality of embryos in Pines and other Gymnospermous plants (560), though all but one 5« 550 ssi 652 553 are more commonly abor- tive or rudimentary. There are other striking peculiar- ities in the fecundation of Pines, &c., which, however, cannot be readily explained without entering into more detail than is here advisable.* In Pines and their allies, moreover, the embryo is not developed until a long time after the application of the pollen, and the filling of the embryo-sac with the cellular tissue which forms the basis of the albumen of the seed; the fruit and seed of true Pines, as is well known, not maturing un- til the year after that in which the blossoms appear. 580'. The further development and the structure of the embryo and the seed must be considered after the Fruit, of which it consti- tutes a part. * See Hofmeister, Untersuchungcn, &c.: Researches into the Fertilization, &e. of the higher Cryptogamia and the Conifer® (Leipsic, 1851), with seven plates devoted to the embryology of Coniferte. FIG. 549. Diagram of the suspensor and forming embryo at Its extremity. 550. The same, with the embryo a little more developed. 551. The same, more developed still, the cotyledons faintly indicated at the lower end. 552. Same, with the incipient cotyledons more manifest. 553. The embryo nearly completed. FIG 554 - 556. Forming embryo from a half-grown seed of Buckwheat, in three stages. 557. Same, with the cotyledons fully developed.308 THE FRUIT. CHAPTER X. , OF THE FRUIT. Sect. I. Its Structure, Transformations, and Dehiscence. 581. The fertilized ovary, increased in size, and usually under- going some change in texture and form, becomes 582. The Pericarp, or Seed-vessel. The pericarp and the seeds it contains together constitute the Fruit; a term which has a more extensive signification in botanical than in ordinary language, being applied to all mature pistils, of whatever form, size, or texture. To the fruit likewise belongs whatever organs may be adnate to the pistils (468). Such incorporated parts, like the fleshy calyx of the Apple and Quince (Fig. 809, 812), sometimes make up the principal bulk of the fruit. 583. Indeed, the calyx, when wholly free from the pistil, sometimes becomes greatly thickened and pulpy after flowering, and is transformed into what appears like a berry ; as in Gaultheria (Fig. 913), where the real fruit is a dry pod within ; and in Strawberry Elite (Fig. 1099), where the fleshy calyxes of a head of flowers each surround a small seed- like fruit, and together form a false multiple fruit, resembling a strawberry. 584. Even the strawberry itself is not a fruit in the strict botanical sense : that is, the edible substance is not a ripened pistil, nor a cluster of pistils, but is the receptacle or ex- tremity of the flower-stalk, greatly enlarged and replete with delicious juice; the true fruits being the minute and seed-like ripened ovaries scattered over its surface ; as plainly appears from a comparison of Fig. 558 with 559. Moreover, a mulberry, FIG. 558. Vertical section of a forming strawberry, enlarged. FIG. 559. Similar section of one half of a ripe strawberry, and of some of the small seed- like fruits, or achenia, on its surface.ITS STRUCTURE AND TRANSFORMATIONS. 309 a fig, and a pine-apple consist of the ripened products of many flowers, crowded on an axis or common receptacle, which makes a part of the edible mass. 585. Under the general name of fruit, therefore, even as the word is used by the botanists, things of very different structure or. of dif- ferent degrees of complexity are confounded. We must distinguish, therefore, between simple fruits, resulting from a single flower, and a multiple fruit, resulting from the parts of more than one flower combined or collected into a mass. We must also distinguish be- tween true fruits, formed of a matured pistil, either alone or with a calyx, &c. adnate to it, and fruits, so called, of which the pericarp does not form an essential part. 586. Obliteration or Alteration. The pericarp, being merely the pistil matured, ■should accord in structure with the latter, and con- tain no organs or parts that do not exist in the fertilized ovary. Some alterations, however, often take place during the growth of the fruit, in consequence of the abortion or obliteration of parts. Thus, the ovary of the Oak consists of three cells, with a pair of ovules in each; but the acorn, or ripened fruit, presents a single cell, filled with a solitary seed. In this case, only one ovule is matured, and two cells and five ovules are suppressed. The ovary of the Horsechestnut and Buckeye is similar in structure (Fig. 777 -780), and seldom ripens more than one or two seeds; but the abortive seeds and cells may be detected in the ripe fruit. The ovary of the Birch and of the Elm is two-celled, with a single ovule in each cell: the fruit is one-celled, with a solitary seed ; one of the ovules or young seeds being uniformly abortive, while the other in enlarging thrusts the dissepiment to one side, so as gradually to ob- literate the empty cell; and similar instances of suppression in the fruit of parts actually extant in the ovary are not uncommon. On the other hand, there are sometimes more cells in the fruit than properly belong to the pistil. For instance, the ovary of Datura Stramonium is two-celled ; but the fruit soon becomes spuriously four-celled by a false partition connecting each placenta with the dorsal suture. So the compound ovary of Flax when young is five- celled, but with a strong projection from the back of each cell (Fig. 500) which at maturity divides the cell into two, thus rendering the fruit ten-celled. And some legumes are divided transversely into several cells, although the ovary was one-celled with a continu- ous cavity in the flower.310 THE FRUIT. 587. Ripening. The pericarp sometimes remains herbaceous in texture, like the pea-pod, or becomes thin, dry, and membranaceous, like the pod of the Bladder-Senna. In such cases it is furnished with stomates, continues to have chlorophyll in its cells, and acts upon the air like an ordinary leaf. In other plants the pericarp thickens, and either becomes hard and dry, like a nut, or else fleshy or pulpy, like a berry (gooseberry, grape, &c.). Sometimes the outer portion softens into flesh or pulp, while the inner portion hard- ens, thus forming a stone-fruit, like the cherry and peach. 587'. Most fleshy or pulpy fruits are tasteless or slightly bitter during their early growth; at which period their structure and chemical composition are similar to that of leaves, consisting of cel- lular with some woody tissue ; and their action upon the atmosphere is likewise the same (346). In their second stage, they become sour, from the production of acids (353) ; such as tartaric acid in the grape ; the citric, in the lemon, orange, and the cranberry ; the malic, in the apple, gooseberry, &c. At this period they exhale very little oxygen, or even absorb that substance from the surrounding air. The acid increases until the fruit begins to ripen, when it grad- ually diminishes, and sugar is formed. In the third stage, or that of ripening, the acids, as well as the fibrous and cellular tissues, gradu- ally diminish as the quantity of sugar increases ; the latter being produced partly at the expense of the former. A chemical change, similar to that of ripening, takes place when the green fruits are cooked ; the acid and the mucilaginous or other products, by the aid of heat reacting upon each other, are both converted into sugar. Mingled with the saccharine matter, a large quantity of vegetable jelly (83) is also produced in most acidulated pulpy fruits, ex- isting in the form of pectine and pectic acid. These arise from the reaction of the vegetable acids during ripening upon the dex- trine and other ternary products accumulated in the fruit. 588. When the walls of a pericarp form two or more layers of dissimilar texture, the outer layer is called the Epicarp, the middle one, Mesocarp, and the innermost, Endocarp. A stone-fruit or drupe, like the peach, consists of two layers, viz. the outer or fleshy layer, which is therefore termed the Sarcocarp, and the inner, or endocarp, the shell or stone, which is also termed the Putamen. 589. Fruits also may be divided into the indeliiscent or closed, and the dehiscent or those that open. Fleshy fruits generally, stone- fruits, and many dry fruits, especially one-seeded ones, such as nuts,ITS KINDS. 311 achenia, &c., remain indehiseent; while most pods or capsules dehisce at maturity. 590. Some pods burst irregularly when ripe and dry; others open and shed their seeds by definite pores, as the Poppy, or by larger holes, chinks, or valves, as the Campanula, Snapdragon, &c.; or by a transverse line cutting off the top of the pod, as in Henbane and Purslane. These are modes of irregular dehiscence. But 591. Dehiscence, when regular and normal, is effected by a vertical separation or splitting, viz. by the opening of one or both sut ures of the ovary (543), or, in a fruit resulting from a compound ovary (548), by the disjunction of the united parts. The several modes of dehis- cence will be characterized under the kinds of fruit in which they occur (607 - 614). Sect. n. The Kinds of Fruit. 592. The various kinds of fruits have been minutely classified and named ; but the terms in ordinary use are not very numerous. A rigorously exact and particular classification, discriminating be- tween the fruits derived from simple and from compound pistils, or between those with and without an adnate calyx, becomes too recon- dite and technical for practical purposes. It is neither convenient nor philosophical to give a substantive name to every variation of the same organ. For all ordinary purposes it will suffice to char- acterize the principal kinds under the four classes of Simple, Aggre- gate, Accessory or Anthocarpous, and Multiple Fruits. 593. Simple FmitS are those which result from the ripening of a single pistil, whether with or without a calyx or other parts adnate to it. This division comprises most of the kinds of fruit which have distinctive names, and those of the other classes are mainly aggre- gations or combinations of these. 594. Simple Fruits may be conveniently divided into Fleshy fruits, Stone fruits, and Dry fruits. The leading kind of the first division is 595. The Berry (Dacca), an indehiscent fruit which is fleshy or pulpy throughout. The grape, gooseberry, currant, cranberry, and tomato are familiar examples. 596. The nesperidium (orange, lemon, and lime) is merely a berry with a leathery rind.312 THE FRUIT. 597. The Pepo, or Gourd-fruit, is also a modification of the berry, with a hard rind, which occurs in the Gourd family. The cucum- ber, melon, and squash are familiar illustrations. A Pepo is an indehiscent, externally firm and internally pulpy fruit, composed usually of three carpels, and with an adnate calyx. In the ovary it is either one-eelled with three broad and revolute parietal placentae, or these placentae, borne on slender dissepiments, meet in the axis, enlarge, and spread, unite with their fellows on each side, and are reflected to the walls of the pericarp, next which they bear their ovules (Fig. 560, 561). As the fruit enlarges, the seed-bearing placentae usually cohere with the walls, and the partitions are oblit- erated, giving the appearance of a peculiar abnormal plaeentation, which only the study of the ovary readily explains. 598. A Pome, such as the apple, pear, and quince (Fig. 809, 812), is a fruit composed of two or more carpels, cither papery, cartilagi- nous, or bony, usually more or less involved in a pulpy expansion of the receptacle or disk, and the whole invested by the thickened and succulent tube of the calyx. It may be readily understood by comparing a rose-hip with an apple. The calyx makes the princi- pal thickness of the flesh of the apple, and the whole of that of the quince. 599. The Drupe, or Stone- Fruit, is a one-celled, one or two seeded indehiscent fruit, with the inner part of the peri- carp (endocarp, or putamen, 588) hard or bony, while the outer (exocarp, or sarcocarp) is fleshy or pulpy It is the latter which in these fruits so readily takes an increased development in cultivation. The name is strictly FIG. 560. Section of the ovaTy of the Gourd. 561. Diagram of one of its constituent carpels. FIG 562. Vertical section of a peach. 563 An almond; where the exocarp, the portion of the pericarp that represents the pulp of the peach, remains thin and juiceless, and at length separates by dehiscence from the endocarp, or shell.ITS KINDS. 313 applicable only to fruits produced by the ripening of a onc-celled pistil; as the plum, peach (Fig. 562), &c.; but it is extended in a general way to such fruits with two or more bony cells enclosed in pulp, as that of the Dogwood, &c. 600. The raspberry and blackberry (Fig. 564) are composed of a great number of miniature stone- fruits, or drupelets, as they might be called, in struc- ture resembling cherries (Fig. 565), aggregated upon, an elongated receptacle. 601. Dry Fruits may be either dehiscent or indekis- cent (589). Of indehiscent dry fruits one of the simplest kinds is 602. The Aclienium, or Akcnc (Fig. 566-573). This includes all one- seeded, dry and hard, indehiscent and seed- like, small fruits, such as are popularly taken for naked seeds. But that they are true pistils or ovaries ripened is evident from the styles or stigmas they bear, or from the scar left by their fall; and a section brings to view the seed within, provided with its own proper integuments. The name has been restricted to the seed- like fruits of simple pistils, as those of the Buttercup (Fig. 566, 567), Anemone, Clematis, and Geum (where the persist- h A YWJ jp® ii Ira w W 569 570 571 FIG. 564. Magnified vertical section of half of a blackberry. 565. Section of one of the grains, or drupelets, more magnified. FIG. 566. Achenium of a common Buttercup, enlarged. 567. Vertical section of the same, showing the seed within. FIG. 568 Achenium of Mayweed (no pappus). 569. That of Cichory (its pappus a shal- low cup). 570. Of Sunflower (pappus of two deciduous scales). 571. Of Sneeze weed (Hele- niurn). with its pappus of five scales. 572. Of Sow-Thistle, with its pappus of delicate downy hairs. 573. Of the Dandelion, its pappus raised on a long beak. 27314 THE FRUIT. ent style usually remains on the fruit as a long tail), and the minute grains of the strawberry (Fig. 559). But it may be extended, as is now generally done, to all such one-celled seed-like fruits result- ing from a compound ovary, and even when invested with an adnate calyx-tube. Of this kind is the fruit of all Composite (Fig. 5G8- 573). Here the tube of the calyx is incorporated with the surface of the ovary, and its limb or border, obsolete in some cases (Fig. 5G8), in others appears as a crown (Fig. 569), cup, a set of teeth or of scales (Fig. 570, 571), or as a tuft of bristles or hairs (Fig. 572, 573), &c., called the pappus. In the Lettuce and Dandelion (Fig. 573), the achenium is rostrate, i. e. its summit is extended into a slender beak. 603. A Utricle is the same as an achenium, only with a thin and bladdery loose pericarp, like that of Goosefoot and Amaranth (Fig. 574, 575). The thin coat commonly bursts irregularly, discharging the seed. In the true Amaranths it opens by a circular line, and the upper part falls as a lid, converting the fruit into a small pyxis (619). 604. A Caryopsis or Grain differs from the last in hav- ing the seed completely filling the cell, and its coat firmly consolidated throughout with the very thin peri- carp, as in wheat, Indian corn, and other cereal grains (Fig. 622-624). Of all fruits this is the kind most likely to be mistaken for a seed. 605. A Nut is a hard, one-celled and one-seeded, indehiscent fruit, like an achenium, but larger, and usually produced from an ovary of two or more cells with one or more ovules in each, all but a single ovule and cell having disappeared during its growth (586) ; as in the Hazel, Beech, Oak (Fig. 576, 1166), Chestnut, Cocoa-nut, &c. The nut is often enclosed or sur- rounded by a kind of involucre, termed a Cupule ; as the cup at the base of the acorn, the bur of the chestnut, and the leaf-like covering of the hazel-nut. 606. A Samara or Kcy-fruil is a name applied to a nut, or achenium, having a winged apex or margin; as in the Birch, Elm (Fig. 578), FIG. 574. Utricle of Chenopodium album, or common Goosefoot. 575. Utricle, or pyxis, of an Amaranth FIG. 67G. Acorn (nut) of White Oak, with its cup or cupule.ITS KINDS. 315 and Ash (Fig. 577). The fruit of the Maple consists of two such fruits belonging to one flower, united by their bases (Fig. 787). 607. Dehiscent Fruits, or Pods, are distinguishable into those consisting of a simple pistil, and those resulting from a compound pistil. 608. Of those originating from simple pistils, the principal kinds are the Follicle and the Legume. These may be taken as the type, of simple fruits. 609. A Follicle is a pod formed of a simple pistil, and dehiscent by the ventral or inner suture alone ; as in the Milkweed, Larkspur, Columbine, Peony, and Marsh-Marigold (Fig. 579). When it opens widely, the pistil may be said to revert to its natural state of a leaf, and it often looks much like one, as in Fig. 492. 610. A Legume is a pod formed by the ripen- 679 ing of a simple pistil which dehisces by both sutures, and so divides into two valves or pieces, as in the Bean and Pea (Fig. 580). This being the ordinary 578 fruit of the Pulse family, accordingly named Leguminosce (or Leguminous plants), the name has been extended to it in descriptive botany, in all cases, whatever the form, and whether dehiscent or not. The legume will be found to exhibit no small diversity in this large fam- ily (799). Among its forms is one termed 611. A LoinCUt. This is a legume divided transversely into two or more one-seeded joints, which usually fall apart at maturity (Fig. 581). Commonly these joints remain closed, as in Desmodium; sometimes they split into two valves, as in Mimosa. 612. A Capsule is the pod, or dehiscent fruit, of any compound pistil. When regularly dehis- cent, as already stated (591), the pod splits lengthwise into pieces or valves. 613. A capsule, necessarily consisting of two or more carpels or , FIG. 577. Samara of White Ash. 578. Samara of American Elm. FIG. 579. Follicle of Caltha palustris, the Marsh-Marigold. FIG. 580. Legume of a Sweet Pea, already dehiscent. 581. Loment of a Tick-Trefoil or Desmodium. *316 THE FRUIT. simple pistils united into one body, will normally dehisce in one of tw o ways. Namely, either the carpels will separate at the line of junction, thus resolving the pod into its constituent elements; or else, these parts remaining united, each cell will open on the back by a splitting of the dorsal suture. The former constitutes 614. Septicidal Dehiscence (Fig. 582, 584), so named because the capsule splits through the septa or partitions (dissepi- ments), each one separating into its two constituent layers, one belonging to each carpel. This occurs in Azalea and its allies, in St. Johnswort, &c. The car- pels, thus becoming separate, in these cases open down their inner suture, like a follicle, and discharge the seeds. When the cells are only one-seeded, after separating septicidally, they often remain closed and fall away separately, as in Mallow, Vervain (Fig. 985), &c. Such closed or nearly closed cells or car- pels of a compound pistil are termed cocci. 615. toculicidal Dehis- cence is that in which the splitting opens into the loculaments (in Latin, loculi) or cells; that is, each carpel dehisces by its dorsal suture (Fig. 583, 585), as in Iris, the Lily, Hibiscus, Evening Prim- rose, &e. The dissepiments here are necessarily borne on the mid- dle of the valves. 616. In the Violet, &c. we have the loculicidal, and in several kinds of St. Johnswort the septicidal, plan of dehiscence in ©ne- edled capsules; the placentas (answering to the partitions) being borne in the former upon the middle of the valves ; while in the latter each placenta is split in two, and one half borne on each mar- gin of a valve. FIG. 582. Dehiscent capsule of Elodea, enlarged, showing septicidal dehiscence. FIG. 583. Dehiscent capsule of Iris, showing loculicidal dehiscence; the lower part cut across, showing the dissepiments borne on the middle of the valves. FIG. 584. Diagram (in cross-section) of septicidal, and, 585, of loculicidal, dehiscence.ITS KINDS. 317 617. Scptifragal Dehiscence is a modification of either the loculicidal or the septicidal, in which the valves fall away, leaving the dissepi- ments behind attached to the axis. Fig. 586 is a diagram representing this in a case of loculicidal opening. Fig. 587; from the common Morn- ing-Glory, is this modifica- tion of the septicidal mode. 618. Instead of splitting into separate pieces, the sutures of the pericarp sometimes open for a short distance at their apex only, as in Cerastium and some other Chickweeds, in Tobacco (Fig. 1050), and in the Primrose (Fig. 943) ; or by mere pores, as in the Poppy. The pod of the Snap- dragon opens by the bursting of a hole towards the top of each cell, not corresponding, perhaps, with any suture. Another anomalous mode of dehiscence, namely, the circumcissile, characterizes 619. The Pyxis or Pyxidium, a pod which opens by a circular hor- izontal line cutting otf the upper part as a lid. The fruits of the Plantain, Henbane, Amaranth (Fig. 575, which is otherwise a utricle), Pimpernel, and Purslane (Fig. 588) are of this kind. 620. A Siliquc is a slender two-valved capsule, with two parietal placentas, from which the valves separate in dehiscence; as in plants of the Cruciferous or Mustard family (Fig. 589), to the fruit of which the term prop- erly belongs. Usually a false partition is stretched across between the two placentas, rendering the pod two-celled in an anomalous manner. 621. A Sllicle or Pouch is merely a short silique, its length not more than twice its breadth; as that of Shep- herd’s-Purse, Candytuft, &c. 622. Aggregate Fruits are those in which a cluster of carpels, all belonging to one flower, are crowded on the receptacle into one mass, as in the raspberry and blackberry taken as a whole (Fig. 564), where the constituent fruits, or ripened carpels, PIG. 586. Septifragal modification of loculicidal, and, 587, of septicidal, dehiscence. FIG. 588. Pyxis or pod of Purslane, the top separating as a lid. FIG. 589. Silique of Cardamine, in dehiscence. 27*.318 THE FRUIT. are little drupes ; also the cone-like fleshy fruit of Magnolia, where the component carpels are a sort of drupaceous follicles, at length opening on the back and summit; and the dry cone of the Tulip-tree, where each carpel forms a sort of samara. None of these aggregate fruits have special names in ordinary use. In descriptive botany it is sufficient to state the kind of fruit the carpels themselves form, and their mode or degree of aggregation. 623. Accessory or Anthocarpons Fruits are those of which the most conspicuous portion, although often appearing like a pericarp, neither belongs to the pistil nor is organically united with it. The apparent berry of Gaultheria, in which a succulent free calyx invests a dry pod and appears to form the real fruit (Fig. 912-914) has already been adverted to (583) ; and the calyx of Shepherdia is similar, forming what appears to be the sarcocarp of a drupe, although it is really free from the achenium it encloses. So, also, the apparent achenium or nut of Mirabilis, or Four-o’clock, is the thickened and indurated base of the tube of a free calyx, which contracts at the apex and encloses the true pericarp as a utricle or thin achenium, but does not cohere with it. The rose-hip, a hollow calyx-tube lined with a hollow receptacle (Fig. 429), and the strawberry (Fig. 428, 558, 559), consisting of a conical enlarged receptacle bearing many minute achenia, may also be regarded as forms of anthocar- pous fruit. 624. Multiple or Collective Fruits are those which result from the aggregation of several flowers into one mass. The simplest of these are those of the Partridge-Berry (Mitchella) and of some species of Honeysuckle (Fig. 859), consisting of the ovaries of two blossoms united into one double berry. The more usual sorts are such as the pine-apple, mulberry, and the fig. These are, in fact, dense forms of inflorescence, with the fruits or floral envelopes matted together or coherent with each other ; and all or some of the parts become succulent. The grains of the mulberry (Fig. 593, 594) are not the ovaries of a single flower, like those of the blackberry which it super- ficially resembles (Fig. 5G4), but belong to as many separate flow- ers ; and the pulp of these pertains to the floral envelopes instead of the pericarp. So that the mulberry is an anthocarpous (623) as well as a multiple fruit. The pine-apple is very similar; only the ovaries or pericarps never ripen any seeds, but all are blended, with the floral envelopes, the bracts, and the axis of the stem they thickly cover, into one fleshy and juicy mass. The fig (Fig. 590-592)ITS KINDS. 319 differs from the pine-apple in haying this succulent axis or receptacle on the outside. It may be compared with such an anthocarpous fruit as a rose-liip (Fig. 429). It results from a multitude of flow- ers concealed in a hollow flower-stalk, if it may be so called, which becomes pulpy and edible when ripe ; and thus the fruit seems to grow directly from the axil of a leaf, without being preceded by a blossom. The minute flowers concealed within, or some of them, ripen their ova- ries into very small achenia, which are commonly taken for seeds. The principal form of multiple fruit which has received a substantive name is 625. The Strobile or (lone, a scaly multiple fruit, resulting from the FIG. 590. A young fig. 591. Yertical section of the game, enlarged. 592. A small slice of the same, more magnified, showing the flowers on the inside. FIG 593. A young mulberry. 694. One of the grains, magnified, showing it to be a pis- tillate flower, with a succulent calyx embracing the ovary 695. The same, less magnified, the succulent calyx cut away. FIG. 596. Strobile or Cone of a Pitch Pine, Pinus rigida. 597. Inside view of one of the scales, showing one of the seeds, and the place from which the other, 598, has been detached.320 THE SEED. ripening of some sort of catkin. The name is applied to the fruit of the Hop, where the large and thin scales are bracts ; but it more especially belongs to the Pine or Fir cone, the peculiar fruit of Co- niferce (Fig. 59G), the scales of which are open carpels (560), bear- ing two or more naked seeds upon their upper or inner face (Fig. 597). A more or less fleshy and closed cone, such as that of Taxo- dium, and especially that of Juniper (Savin, Red Cedar, &c.), which at maturity imitates a berry, has been termed a Galbalus. CHAPTER XI. OF THE SEED. Sect. I. Its Structure and Parts. 626. The Seed, like the ovule (561), of which it is the fertilized and matured state, consists of a Nuceeus, or kernel, usually en- closed within two Integuments. 627. Its Integuments, &C. The outer, or « proper seed-coat, corresponding to the ex- (T terior coat of the ovule, is variously termed the Episperm, Spermoderm, or more com- uvT®// monly the Testa (Fig. 599, b). It varies greatly in texture, from membranaceous or papery to crustaceous or bony (as in the Papaw, Nutmeg, &c.), and also in form, being sometimes closely applied (conformed) to the nucleus, and in other cases loose and cellular (as in Pyrola, Fig. 927, and Sullivantia, Fig. 843), or ex- panded into wings (as in the Catalpa and Trumpet-Creeper, Fig. 601), which render the seeds buoyant, and facilitate their dispersion by the wind ; whence winged seeds are only met with in dehiscent fruits. The wing of the seed of Pines (Fig. 598) is a part of the surface of the scale or carpel to which it is attached, and which separates with it. For the same purpose, the testa is sometimes FIG. 599. Vertical magnified section of the (anatropous) seed of the American Linden : a, the hilum; 6, the testa ; c, the tegmen ; d, the albumen; e, the embryo. 600. Vertical section of the (orthotropous) seed of Helianthemum Canadense : a, the funiculus.ITS STRUCTURE AND PARTS. 321 provided with a tuft of hairs at one end, termed a Coma ; as in Epilobium and Milkweed (Fig. 602). In the Cotton-plant, the whole surface of the seed is covered with long wool. It should likewise he noticed, that the int numerous small seeds is furnished with a coating of small hairs containing spiral threads (one form of which is represented in Fig. 44), and usually appressed and con- fined to the surface by a film of mucilage. When the seed is moistened, the mucilage softens, and these hairs spread in every direction. They are often ruptured, and the extremely attenuated elastic threads they contain uncoil, and are protruded in the greatest abundance and to a very considerable length. This minute mechanism subserves an obvious purpose in fixing these small seeds to the moist soil upon which they lodge, when dis- persed by the wind. Under the microscope, these threads may be observed on the seeds of most Polemoniaceous plants, and on the aclienia of Labiate and Composite plants, as, for example, in many species of Senecio, or Groundsel. In Peony the testa becomes fleshy or baccate; in Magnolia it imitates a drupe. 628. The inner integument of the seed, called the Tegmen or Endopleura, although frequently very obvious (as in Fig. 599, c), is often indistinguishable from its being coherent with the testa, and is sometimes altogether wanting. 629. The stcdk of the seed, as of the ovule, is called the Fu- niculus (Fig. 600, a). The scar left on the face of the seed, by its separation from the funiculus at maturity, is termed the Hilum. The chalaza and rhaphe, when present, are commonly obvious in the mature seed, as well as in the ovule (564 — 568), and the name and relations of these several parts in the seed are the same as in the ovule. Also the terms orthotropous, anatropous, campylotropous, &c., originally applied to the ovules, are extended to the seeds which result from them ; so that we may say, Seeds anatropous, as well as Ovules anatropous, &c. 630. Aril or Arillus. Some seeds are furnished with a covering, (usually incomplete and of a fleshy texture,) wholly exterior to their proper integuments, arising from an expansion of the apex of the FIG. 601. The winged seed of Trumpet-Creeper. FIG. 602. Seed of Milkweed (Asclepias Comuti), with its coma or tuft.322 THE SEED. seed-stalk, or funiculus, or of the placenta itself when there is no manifest seed-stalk. This is called the Aril. It forms the pulpy envelope of the seed*of Podophyllum, Euonymus, and Ce- lastrus, or it appears as a mere lateral scale in Turnera, or as a tough and lacerated body, known by the name of mace, in the Nutmeg. In the White Water-Lily it is a thin and delicate cellular bag, open at the end (Fig. 603). The Aril does not appear in the ovule, hut is developed subse- quent to fertilization, during the growth of the seed. Of the same or similar nature is the Caruncle found at the hilum in Polygala, forming a loose lateral appendage. Strictly speaking, it is to be distinguished from the Strophiole (like that of Euphor- bia), which is a cellular growth from the micropyle; but the two are not well discriminated. An analogous cellular growth takes place on die rhaplie of the Bloodroot, of the Prickly Poppy, and of Dicen- tra, forming a conspicuous crest on the whole side of the seed. 631. The Nucleus, or Kernel of the seed, consists of the Albumen, when this substance is present, and the Embryo. 632. The Albumen, which has also been termed the Perisperm or the Endosperm, has already been described (125) as the floury part of those seeds in which an amount of nourishment for the germi- nating plantlet is stored up outside of the embryo. This was called by Gtertner the albumen of the seed, from some fancied anal- ogy with the white of an egg as to situation or function ; — an un- fortunate term, on account of its liability to be confounded with the quaternary chemical substance of the same name (357), one of the forms of proteine. Being in general use, the term cannot now well be discarded. 633. The Albumen of the seed consists of whatever portion of the tissue of the ovule persists, and becomes loaded with nutritive mat- ter accumulated in its cells, — sometimes in the form of starch- grains principally, as in wheat and the other cereal grains; some- times as a continuous, often dense, incrusting deposit, as in the cocoa- nut, the date, the coffee-grain, &c. When it consists chiefly of starch-grains, and may readily be broken down into a powder, it is said to ba farinaceous, or mealy, as in the cereal grains generally, in buckwheat, &c. When a fixed oil is largely mixed with this, it becomes oily, as in the seed of the Poppy, &c.; when more compact, but still capable of being readily cut with a knife, it is fleshy, as in FIG. 603. A seed of the White Water-Lily, with its sac-like arillus, magnified.THE ALBUMEN AND EMBRYO. 323 the Barberry, &c.; when it chiefly consists of mucilage or vegetable jelly, as in the Morning-Glory and the Mallow, it is said to be muci- laginous ; when it hardens more, and becomes dense and tough, so as to offer much resistance to the knife, as in the Coffee, the Blue Cohosh, &e., it is corneous, that is, of the texture of horn. Between these all gradations occur. Commonly the albumen is a uniform deposit. But in the nutmeg, as also in the seeds of the Papaw (Fig. 658), and of all plants of the Custard-Apple Family, it presents a wrinkled or variegated appearance, owing to numerous transverse divisions, which are probably caused by inflections of the innermost integument of the seed: in these cases the albumen is said to be rumi- nated. The albumen may originate from new tissue formed either within the embryo-sac (579), which is probably the more common case ; or in the nucleus of the ovule exterior to the embryo-sac, which is certainly the case in the Water-Lily and its allies, and in Saururus; for here the thickened embryo-sac persists within or at one extremity of the copious albumen ; or both kinds may coexist. When this is the case, the outer albumen may be distinguished as the perisperm, and the inner as the endosperm. G34. Seeds provided with albumen (as in Fig. 599, 600, 605, 606, 609, CIO -616, 622, &c.) are said to be albuminous; those destitute of it (as in Fig. 607, 629, 110, 120, &c.) are exalbuminous. The comparative amount of the albumen, and its relation to the embryo in various seeds, may be seen on inspection of many of the subjoined figures. t> a 635. The Embryo, or Germ, being an initial plantlet or individual, is of course the most important part of the seed: to its production, protec- FIG. 604. Seed of a Violet (anatropous), enlarged: a, hiluin or scar; ft, rhaphe; c, chalaza. FIG. 605. Vertical section of the same, showing the straight embryo in the axis of themealy albumen. FIG. 606. Vertical section of the (orthotropous) seed of Buckwheat, showing the embryo folded round in the mealy albumen. FIG. 607. Vertical section of the (anatropous) seed of Elodea Virginica, the embryo com- pletely filling the coats. FIG. 608. Seed of Delphinium tricorne (anatropous), enlarged; a, the hilum; ft, the rhaphe ; c, the chalaza. 609. Vertical section of the same: c, the chalaza; d, the testa; e, the tegmen ; f the albumen ; g, the minute embryo near the hilum, a.324 THE SEED. tion, and support all the other parts of the fruit and flower are sub- servient. It becomes a plant by the mere development of its parts : it therefore possesses, in a rudimentary or undeveloped state, all the essential organs of vegetation, namely, a root, stem, and leaves. Its general structure and development have already been explained in considerable detail (118 - 130). 636. In albuminous seeds it is naturally the smaller and its parts the legs developed in proportion to the amount of albumen, and the several organs are developed or even formed in germina- tion. In exalbumi- nous seeds', where the embryo con- stitutes the whole kernel, its several parts are ordina- rily conspicuous, although they are often more or less disguised by thickening; as the cotyledons in the Almond (Fig. 108) and Cherry (Fig. Ill), and especially in the Pea (Fig. 118), the Acorn (Fig. 120), the Horsechestnut (Fig. 630), and the like. 637. The parts of the embryo, as already illus- trated (120) are the Badicle, the Cotyledons, and the Plumule. The radicle is the axis, or rudimen- tary stem, — the first internode of the axis (121, 157), from the lower extremity of which the root is produced, while the other bears the cotyledons, i. e. the leaves of the first node ; and the plumule is the bud which crowns the summit of the radicle. 638. Owing to the mode of its formation (580), the radicle of the FIG. 610. Vertical section of the seed of a Peony, showing a small embryo near the base of the copious albumen. 611. The embryo, detached, and.more magnified. FIG. 612. Section of a seed of Barberry, with a straight embryo in the axis of the albu- men. 613. Its embryo, detached. FIG. 614. Section of a Potato-seed, showing the embryo coiled in the albumen. 615. Its embryo, detached. FIG 616. Section of the seed of Mirabilis or Four-o’clock, showing the embryo coiled round the outside of the albumen. 617. Its embryo, detached, and partly spread out. FIG 618. Embryo of the Pumpkin, with its short radicle and large and flat cotyledons, seen flatwise. 619. A vertical section of the same, viewed edgewise.THE EMBRYO. 325 embryo is always near to and points towards the micropyle of the seed, viz. to what was the orifice of the ovule; and if the embryo be straight (as in Fig. 605), or merely partakes of the curvature of the seed, the cotyledons point to the opposite extremity of the seed, that is, to the ehalaza. The position of the radicle as respects the liilum varies with the different kind of seed. In the orthotropous form, as in Heliantliemum (Fig. 600) and Buckwheat (Fig. 606), the radicle necessarily points directly away from the hilum. In the anatropous form, as in the seed of the Lin- den (Fig. 599) and Violet (Fig. 604, 605), the extremity of the radicle is brought to the immediate vicinity of the hilum ; and so it is, although in a different way in the campylotropous seed (Fig. 620, 621) ; while in the amphitro- pous, the radicle points away from the hilum laterally, at a right angle to the funiculus. As the nature of the ovule and seed may usually be ascertained by external inspection, so therefore the situa- tion of the embryo within, and of its parts, may often be inferred without dissection. But the dissection of seeds is not generally a difficult operation. 639. The position of the embryo as respects the albumen, when that is present, is various. Although more commonly in the axis, it is often excentric, or even external to the albumen, as in all Grasses and cereal Grains (Fig. 622-624), in Polygonum (Fig. 1111), &c. When external or nearly so, and curved circularly around the albu- men, as in Goosefoot, Chickweed (Fig. 621), and Mirabilis (Fig. 616), it is said to be peripheric. When bent or folded in such a FIG. 620. Campylotropous seed of the common Chickweed (Stellaria media), magnified. FIG. 621. Section of the same, showing the embryo coiled around the outside of albumen. FIG. 622. Vertical section of a grain of Indian Corn, passing through the embryo: c, the cotyledon ; p, the plumule ; r, the radicle. (A highly magnified portion of the albumen, which makes up the principal bulk of the grain, is shown in Fig. 70, p. 54.) 623. Similar section of a grain of Rice. 624. Vertical section of an Oat-grain : a, the albumen ) c, the cotyledon ; p, the plumule ; and r, the radicle of the embryo. 28326 THE SEED. way that the radicle lies along the edges of the cotyledons, the latter are said to he decumbent (Fig. 700) ; or when the radicle rests against the back of one of them, or in proximity to it (Fig. 705), they are incumbent. 640. The direction of the embryo with respect to the pericarp is also particularly noticed by systematic writers; who employ the terms ascending, or radicle superior, when the latter points to the apex of the fruit; descending, or radicle inferior, when it points to its base ; centripetal, when the radicle is turned towards the axis of the fruit; centrifuged, when turned towards the sides ; and vague, when it bears no evident or uniform relation of the kind to the pericarp. 641. As to the number of its cotyledons, or the degree of com- plexity or simplicity of the embryo, the principal types have already been considered (128). The plan of the embryo in Exogenous plants is to have a pair of opposite cotyledons ; that is, the embryo is dicotyledonous, and such plants are denominated Dicotyledo- nous Plants. 642. A modification of this plan occurs in Pines and most other CJonifera, in which the cotyledons are increased to three, four, six, or even to fifteen, in a whorl (Fig. 133, 134) ; and this embryo of highest complexity is called polycotyledonous. The embryos of some Leguminous or Cruciferous plants are occasionally found, with three cotyledons, as an accidental deviation. 643. But in all Endogenous plants only one cotyledon appears, i. e. only one seed-leaf on the primary node ; if two or more rudi- mentary leaves are present, they are alternate, and all but the first belong to the plumule. Here the em- bryo is monocotyledonous, and hence Endogens are also termed Monocoty- ledonous Plants. The monocoty- ledonous embryo does not usually pre- sent a manifest distinction into radicle, cotyledons, and plumule, as the dicoty- ledonous ; but often appears like a ho- mogeneous and undivided cylindrical or club-shaped body, as in Iris FIG. 625. Seed of Triglochin palustre; the l’haphe, leading to the strong chalaza at the summit, turned towards the eye. 626. The embryo detached from the seed-coats, showing the longitudinal chink at the base of the cotyledon ; the short part below is the radicle.' 627. Same, with the chink turned laterally, and half the cotyledon cut away, bringing to view the plumule concealed within. 628 A cross-section through the plumule, more magnified.THE EMBRYO. 327 (Fig. 131) and Triglochin (Fig. 62G). In the Latter, however, close inspection reveals a vertical slit or chink just above the radicular extremity, through which the plumule is protruded in germination. If the embryo be divided parallel with this slit, the plumule is brought into view ; as in Fig. G27. If a horizontal section be made at this point (as in Fig. 628), the cotyledon is found to be wrapped around the enclosed plumule, sheathing it, much as the bud and the younger parts of the stem are sheathed by the bases of the leaves in most monocotyledonous plants. The plumule is more manifest in Grasses, especially in the cereal grains, and more complex, ex- hibiting the rudiments of several concentric leaves, or of a strong bud, previous to germination (Fig. 622-624, and 126-128). In many cases, however, no distinction of parts is apparent until ger- mination commences ; as in the Onion, Iris (Fig. 131), &c. 644. In several Dicotyledonous plants one cotyledon is smaller than the other, viz. the inner one, when the embryo is coiled or folded. And in all the species of Abronia this cotyledon is wanting, so that the embryo becomes tech- nically monocotyledonous. In the Dodder, a genus of leafless parasitic plants of the Convolvu- lus family, the embryo also is entirely destitute of cotyledons (Fig. 148). Here these organs aj'e suppressed in an embryo of considerable size; but in most such parasites, the embryo is very minute, as well as reduced to the greatest degree of simplicity, and seems to remain until germination in a very rudimentary state. 645. Sometimes the two cotyle- dons of a dicotyledonous embryo are consolidated, or more or less coherent by their contiguous faces into one mass, when they are said to be conferruminate, as in the Horsechestnut, Buckeye (Fig. 629, 630), and the Chestnut. In these, as in other embryos with very thick cotyledons, the latter are FIG. 629. Section of the seed of a Buckeye. 630. A Buckeye iu germination.328 THE SEED. necessarily hypogceous in germination (124, 12G), that is, they re- main underground, enclosed within the coats of the seed, yielding their abundant store of nourishment to the radicle and the plumule; and the first leaves that appear are those of the plumule. Sect. II. Germination. 646. Germination is the initial act of growth, by which the embryo in a seed develops into a pluntlet. The steps of the early growth have already been sufficiently explained in an early part of this vol- ume (119 -132). 647. The seeds of some plants (such as the Red Maple) germi- nate shortly after falling to the ground; those of most other plants not until the next year, or even later. How long seeds may retain the power of germinating is uncertain, and is extremely variable in different species and families. Those of many plants under ordinary circumstances can rarely be made to grow after two or three years; some will germinate pretty well after several years keeping; and the seeds of certain Leguminous plants have been known to germi- nate when sixty years old. But the current accounts of wheat, &c. being raised from grain taken from ancient mummies, circumstan- tially authenticated as some of them appear to be, must be received with the greatest misgiving, if not with entire incredulity. One of the most probable cases of germination of ancient seeds on record is that given by Dr. Lindley, of some Raspberries, " raised in the gar- den of the Horticultural Society from seeds taken from the stomach of a man, whose skeleton was found thirty feet below the surface of the earth, at the bottom of a barrow which was opened near Dorches- ter. He had been buried with some coins of the Emperor Hadrian; and it is therefore probable that the seeds were sixteen or seventeen hundred years old.” Most seeds, when buried deep in the soil, where they are subject to a uniform and moderate temperature, and removed from the influenee'of the air and light, may be in a favorable state for the preservation of vitality, and would be likely to germi- nate when brought to the surface after a considerable interval. But the possibility of mistake or of collusion must be more thoroughly eliminated before a case of such extraordinary tenacity of life, under conditions in some respects very unfavorable, can be considered as well established.GERMINATION. 329 G48. The conditions requisite to germination are exposure to moisture and to a certain amount of heat, varying from 50° to 80° (Fahrenheit) for the plants of temperate climates, to which must be added a free communication with the air. Direct light, so essential to subsequent vegetation, is unnecessary, and generally unfavorable, to germination. The degree of heat required to excite the latent vitality of the embryo is nearly uniform in the same species, but widely different in different plants ; since the common Chickweed will germinate at a temperature not far above the freezing-point of water, while the seeds of many tropical plants require a heat of 90° to 110° (Fahrenheit) to call them into action, and are often exposed to a considerably higher temperature. Seeds are in the most favorable condition for germination in spring or summer, when loosely covered with soil, which excludes the light while it freely admits the air, moistened by showers, and warmed by the rays of the sun. The water which is slowly absorbed softens all parts of the seed ; the embryo swells, and bursts its envelopes, or the elon- gating radicle is protruded from them, and all the parts grow or unfold in the manner already described, each organ in its proper medium, the root being developed in the soil, and the stem and leaves in the air. G49. The nourishment which the embryo requires during germi- nation is furnished by the starch, &c. of the albumen (632), when this substance is present in the seed; or by starchy or other nutri- tive matter accumulated in its own tissue (03 6,123). But as starch is insoluble in cold water, certain chemical changes are necessary to bring it into a fluid state, so that it may nourish the embryo. These changes are incited by the proteine or neutral azotized products (854), which are largely accumulated in the seed, either in the ' albumen or in the embryo itself, and which take the initiative in all: the transformations of vegetable matter (27). In the germinating seed, just as in growth from a bulb or tuber, the changes essentially consist in the transformation of the starch, first into dextrine, or gum, and thence into sugar, a part of which is destroyed by resolu- tion, first into acetic acid, and finally into carbonic acid and water, with the abstraction of oxygen from the air, and the evolution of heat (349, 370-373), while the remainder is rendered directly sub- servient to the growth of the plantlet. The reason why light, so essential to subsequent growth, impedes or prevents incipient ger- mination, becomes evident when we remember that it incites the 28*S30 REPRODUCTION IN decomposition of carbonic acid, and the fixation of carbon by the plant (344 - 350) ; while germination is necessarily attended by an opposite transformation, namely, the destruction of a portion of or- ganized matter, with the evolution of carbonic acid.* In germina- tion, as in any other act in which matter is transformed or trans- ferred, there is a certain expenditure of force and loss of organized material. The plantlet is obliged to decompose and destroy a part of the starch or other material provided for its initial growth, in order that it may transform the rest into dextrine and sugar, and this again into cellulose or the material of the new cells formed in its growth. 650. The study of the seed, and of the development of the em- bryo it contains into a plantlet, completes the cycle of vegetable life in the higher grade of Phtenogamous plants, and brings us back to our starting-point (118, 119). CHAPTER XII. OP REPRODUCTION IN CRYPTOGAMOUS OR FLOWERLESS PLANTS. G51. The lower grade of Cryptogamous or Fi.owerless Plants (Chap. II. Sect. I.) would now require, to be considered, both as to the vegetation and their reproduction. But the plan of structure in each principal Cryptogamous family is so peculiar, and the organs of fructification especially so diverse, that their morphology cannot lie presented under one common type, as in Phae- nogamous vegetation. Each great family or group would have to be separately treated, and with much fulness of illustration, to make * Seeds may casually germinate while attached to the parent plant, especially such as are surrounded with pulp, like those of the Cucumber and Melon. The process is liable to commence in wheat and other grain, when protracted warm and rainy weather occurs at the period of ripening; and the albumen becomes glutinous and sweet, from the partial transformation of the starch into dextrine and sugar. In the Mangrove, which forms dense thickets along tropical coasts, germination habitually commences in the pericarp while the fruit remains on the tree; and the radicle, piercing the integuments which enclose it, elongates in the air; such a plant being, as it were, viviparous.CRYPTOGAMOUS OR FLOWERLESS PLANTS. 331 the subject intelligible to the unpractised student. This can hardly be done in so elementary a work as the present, but requires a sepa- rate treatise. The student who has intelligently studied the present volume up to the present point, is prepared for the more difficult study of the structure of Cryptogamous plants, in the only general work of the kind that has yet appeared in the English language, viz. Berke- lej’’s Introduction to Cryptogamic Botany. An enumeration of the Cryptogamous orders, with a brief notice of their structure and sub- ordinate divisions, may be found in the systematic part of the pres- ent work. A slight sketch of their grades of development as to vegetation has already been given (97-113). We here attempt to present merely a very brief and general account of their plan of reproduction, divested as far as possible of technical terms. G52. Taken collectively, we distinguish this lower series of the vegetable kingdom by negative characters only; saying that these plants do not bear true. flowers (consisting essentially of stamens and pistils), and accordingly do not produce seeds, or bodies consisting of a distinguishable embryo plantlet, developed in an ovule through fertilization by pollen. Their spores (97), or the bodies produced in their fructification by which they are propagated, and which there- fore answer to seeds, are single cells, at least in most cases. These, as they germinate in the soil, or whatever medium they live in, un- dergo a development at the time of their germination which has been compared with that of the embryonal vesicle (579) during its devel- opment into the embryo in the ovule ; and by growth directly give rise to the plant. 653. It was once thought probable, that these spores were pro- duced, and were capable of developing into the plant without being fertilized by other cells answering to pollen; or at least that this was the case in all the lower orders, such as Algse and Fungi, and in some of the highest, such as Ferns. But the sagacious Linnrcus, by nam- ing them Cryptogamous plants (i. e. plants with concealed organs of reproduction) seems to have recorded his belief that they were really bisexual, or furnished with two sorts of organs, the fertilizing and the ] fertilized. A series of important discoveries, for the most part of) recent date,, have proved this to be so, — have made known a true fecundation in numerous species of every Cryptogamous order, and! in their lowest as well as their highest forms, thus leaving no doubt! of its universality. The apparatus and the processes of reproduction,1 however, are wonderfully varied in the different groups of Cryp-1332 REPRODUCTION IN togamous plants. A few examples may be adduced, illustrative of the principal modes, beginning with the simplest plants. 654. Reproduction in Plants of a Single Cell (100). All such simple one-celled plants as Protococcus and the like (Fig. 79 - 83, 18 - 22), Desmidiace* and Diatomaceae, are freely propagated by cell-multi- plication (33 — 36), — the division of their protoplasm or whole living mass into bodies which directly become new cells like the parent,— or by original cell-formation in their interior (29). This is non- sexual reproduction, and essentially answers to the well-known prop- agation of Phamogamous plants by buds, bulbs, offsets, &c. It is probable that this may not go on indefinitely in any plant. At any rate, not only do all the higher plants propagate in a different way, viz. by flowers, producing seeds, but probably all plants of the lower grade also have a sexual reproduction in some form or other. It is certainly the case in many one-celled plants, and in others ahnost equally simple in structure. As in Phamogamous plants, sexual reproduction essentially depends upon the mingling of the materials of two distinct cells (as the pollen-cell and the embryonal vesicle, 579) ; and these cells in the lowest forms of vegetation represent individual plants. The simplest mode of such reproduction in the lowest plants, and that longest known, is what has been termed 655. Conjugation. This is the mode in which two vast tribes of microscopic one-celled aquatic plants, the Desmidiaceas and Diato- macea1, are reproduced. They multi- ply rapidly, and apparently without limit, by successive division into two equal parts, which separate, each be- coming like the original. But at length two of these individuals, being en- dowed with the power of movement, come into contact; the firm or often silicious cell-wall ruptures or gives way in a definite manner at the place of junction, and the whole contents of the two conjugating cells or individu- als are commingled into one mass of protoplasm, &c.; this soon has a coat of cellulose formed around it, FIG. 631. Magnified individual of Closterium acutum, after Ralfs. 632. Two individuals more magnified, in conjugation ; their cells opening one into the other, and the contents min- gled ; in 633, condensing ; in 634, collected and formed into a spore.CRYPTOGAMOUS OR FLOWKRLESS PLANTS. 333 and is now a spore, which when it grows begins a new series of in- dividuals developed by successive division. 65G. In Alga consisting of a Single Row of Cells one tribe presents the same mode of reproduction, and the various species of Zygnema or Spirogyra, found in almost every pool of fresh water at different times in spring and summer, afford the readiest illustrations of conjugation, which low powers of the microscope suffice to exhibit. These green threads when magnified are seen to consist of single rows of cylindrical cells joined end to end. The cells being all alike and equally capable of conjugation, each is as it were an individual. At a certain season, a protuberance appears on the corresponding parts of certain cells of two adjacent threads; the budding growth continues until the two come into contact; the intervening walls are then absorbed, opening a free communication between the cavities of the two cells ; mean- while the green matter and protoplasm, before arranged in some definite shape in each species (more commonly in one or more spiral bands), break up into a granular mass floating in the water of the cell; this all passes over from one cell to the other, — sometimes to the one plant and sometimes to the other in adjacent cells, — and is mingled with the similar contents of the cell which receives it; and the united product is condensed into a green protoplasmic mass, which, acquiring a coat of cellulose, be- comes a new cell or spore, in due time germinating into a new plant. 657. In reproduction by conjugation, the two cells or individuals concerned are alike; one is as much the fertilizer or the fertilized as the other. But the clear distinction of sexes which all the higher Cryptogamous no less than Phoenogamous plants exhibit, is also mani- fested in those of the simplest structure, viz. in plants consisting of single cells, or of rows or clusters of similar and essentially inde- pendent cells. That is, even these afford examples of FIG. 63o. Magnified view of two conjugating filaments of Zygnema, showing all the stages of the process by which the cells from two filaments form each a corresponding protuberance, these come into contact, the intervening walls are absorbed, and the contents pass from one cell into the other, condense, acquire an investing membrane, and so form a spore : the stages are represented from above downwards ; a completed spore is seen at the bottom, on the right.334 REPRODUCTION IN 658. Direct Fertilization of Spores by Spcrmatozoids from an Anthe- ridium; the latter answering to the anther, or essential part of the stamen, of Phsenognmous plants. Cohn * has shown that even Volvox — an undoubted vegetable, consisting of microscopic one- celled plants of rounded form, grouped into a spherical colony — lias a true sexual propagation, like that of the higher green Alga’, some of the individuals or cells of the sphere producing anllieridia or fer- tilizing cells, while others produce spores, or bodies which become such on being fertilized by the antheridia, which alone renders them capable of germination. A good general idea of bisexual reproduction in the simplest Algte may best be obtained from a brief abstract of what has lately been discovered by Pringsheim and Cohn in two or three common species of comparatively easy investigation. 659. Vaucheria is a genus of several species of green Algm, con- sisting of simple but indefinitely branching cells (Fig. 89). In fruc- tification, the whole contents of the more or less enlarged extremity of some of the branches, or of a special projection from the side of the cell, separate from the general contents of the plant, con- dense into a globular green mass (Fig. 89 a), and become a spore, which at length escapes by a rupture of the walls (Fig. 90), moves freely about in the water for some hours, then fixes itself, and ger- minate^, elongating directly into a thread-like and at length branch- ing plant, like the parent. Here there appears, and was generally thought to be, reproduction without fecundation. Vaucher, however, more than half a century ago, noticed one or more horn-shaped pro- jections in the vicinity of the spore-bearing portion, which he sus- pected to be the analogues of the anther. Nothing had been found to verify this view until the year 1854, when Pringsheim, of Berlin, discovered the fecundation and verified this conjecture. The horn- shaped body is an antheridiutn, or the analogue of the anther. It produces myriads of extremely minute corpuscles, of oblong shape, and furnished with a bristle or cilia at each end, by the vibration of which they move freely in the water. These are spermatozoids (so called from their obvious resemblance to the spermatozoa of ani- mals), and the analogues of pollen. At the proper time the anthe- ridium bursts at the summit, and discharges the spermatozoids ; at this time the wall of the projection which contains the spore likewise opens; numbers of the free-moving spermatozoids find their way * In Comptes Rendtis, vol. 43, 1S56, ancl Ann. Sci. Nat. ser. 4, vol. 5, p. 323.CEYPTOGAMOUS oe floweeless plants. 335 into the opening and into contact with the forming spore, or even penetrate its substance ; it being an amorphous mass, coated with protoplasm only. But, as a consequence of fecundation by one or more spermatozoids, a wall of cellulose is presently formed on its surface, converting it into a proper specialized cell or spore.* GGO. iEdogonium is a genus of simple Algte of the Conferva tribe, consisting of a row of cylindrical cells placed end to end, as in Fig. 639. Some of these cells, usually shorter than the rest, become tumid, and, without conjugation, have their whole green contents transformed into a spore resembling that of Zygnema (Fig. 635) and Vaucheria (Fig. 90). The fertilization of this spore has re- cently been discovered by Pringsheim.f He ascertained that other cells of the same little plant produce a great number of minute ovoid bodies, which he names Androspores: these escape by the opening of the mother cell, moving about freely by the vibration of a crown of cilia attached near the smaller end. One or more of these androspores fix themselves by the smaller end upon the surface of the cell in which a large ordinary spore is forming, or in the vicinity, and germinate there, growing longer and narrower at the point of attachment, while near the free end a cross partition forms, and some- times another, making one or two small cells ; this is the true anthe- ridium; for in it a crowd of spermatozoids are formed, also endowed with motivity by means of vibratile cilia. Now the top of the an- theridium falls off as a lid, the spermatozoids escape; the spore-cell at this time opens at the top; one of the spermatozoids enters the opening, its pointed end foremost; this becomes stationary upon or slightly penetrates the surface of the young spore, into which its contents are probably transferred, by rupture or by endosmosis, and a coat of cellulose is then, but not till then, deposited upon it, com- pleting its organization as a spore. This spore, as in the preceding cases, in due time germinates, and grows directly into a plant like the parent. .But in Bolbochcete, according to Pringsheim, and in Sphseroplea, as investigated by Colin,) the spore in germination converts its contents by successive division into a large number of small, oval or oblong bodies, furnished with two long cilia on a short * Pringsheim, in the Proceedings of the Royal Academy of Sciences, Berlin, March, 1855, and Ann. Sci. Nat. ser. 4, vol. 3, p. 363. t Op. supra cit. May, 1856, and Atm. Sci. Nat. ser. 4, vol. 5, p. 250. } Op. supra cit. May, 1855, and Ann. Sci. Nat. 1. c. p. 186, pi. 12, 13.336 REPRODUCTION IN beak at one end, and which from their extreme resemblance to ani- malcules and their lively movements are called Zoospores. And these zoospores germinate by elongation and the formation of trans- verse partitions into adult thread-like plants, consisting of a row of cells. The whole contents of the cells of some adult individuals of Sphieroplea are formed into large green spores, as yet without a coat; those of different individuals give rise to myriads of slender sperma- tozoids, moving by means of a pair of cilia fixed at the narrow end. These escape from the parent cell through a small perforation which now appears, enter the spore-bearing cells of the fertile plant through a similar perforation, play around the spores, and at length one or more of them drives its pointed extremity into their naked surface; after which, fertilization being accomplished, a thick coat of cellulose is deposited to complete the spore. 661. That in the Fucacese or olive-green Seaweeds, the highest tribe of Alga:, the large spores are fecundated by spermatozoids, or minute lively-moving cells produced in antheridia, was demonstrated by Thuret in the year 1850.* And in more recent memoirs | he has shown that the fertilization takes place through direct contact of the spermatozoids with the naked surface of the unimpregnated spore, then having only a protoplasmic coating; and that these spores will not develop unless so fertilized. Through the researches of Thuret and others, antheridia are now well known in the remaining or rose-red series of Alga:, although their spermatozoids are not known to be endowed with motivity. The same appears to be the case with Lichens, the bodies described by Itsigsohn,J being probably of the nature of spermatozoids or fertilizing cells. In the vast family of Fungi there are similar indications of antheridia and spermatozoids, but the fecundation is not yet clearly made out. 6C2. Fertilization by Spermatozoids of a Cell in a Pistilidium, which becomes a Sporangium. In all the foregoing cases, the spores them- selves are the subjects of direct fertilization. But in Mosses, Liverworts, &c. (in which the two kinds of organs have long been recognized and their functions to some extent understood), the contents of the antheridium act upon an organ which, in conse- * Ann, Sri. Nat. ser. 3, vol. 14 and 16, 1850-1. See Harvey, Nereis Bor.- Amer. in Smithsonian Contributions, 1852, &c. f Op. cit. ser. 4, vol. 2 and 3, 1854, 1855. J In Botanische Zeitung, 1850.CRYPTOGAMOUS OR FLOWERLESS PLANTS. 337 quence of fertilization, develops into a sort of pod, the Sporangium or Spore-case, filled with a multitude of spores which receive no in- dividual fecundation ; this organ, from its general analogy to the pistil, has been termed a Pistillidium. The antheridia of Mosses and the like occur either in the axils of the leaves, or collected into a head at the summit of the stem. They are found either in the same heads as the pistillidia, or in distinct heads on the same individuals (moncecious), or on separate individuals (dioe- cious). The antheridium (Fig. 1307) is merely a cylindrical or club-shaped sac, composed of a single layer of cells, united to form a delicate membrane; within which are developed vast numbers of minute, very delicate cells, completely filling the sac. The sac bursting at its apex when mature, the delicate vesicles are discharged. Each of these contains a slender filament, thick- ened at one end and tapering off to a fine point at the other: it may be seen through the transparent walls, spirally coiled up in the interior of each vesicle. When these vesicles are extruded in water under the microscope, the contained filaments may be seen to execute lively movements, wheeling round and round in the vesicle, or, when dis- engaged from the latter, and assuming a corkscrew form, at the same time advancing forward, the thin end of the filament almost always preceding. Minute observation, which is very difficult, both from the rapidity of the motion (which, however, is arrested by poisons) and from the great delicacy of the whole structure, shows that the movements arise from two long and extremely delicate cilia, attached to the tapering end of the filament. These are the spermatozoids, or true fertilizing organs. The pistillidia (Fig. 1306), which ap- pear at the same time as the antheridia, and often mixed with them, are flask-shaped bodies (like an ovary in shape), with a long neck (resembling a style), composed of a cellular membrane. The neck is perforated by an open canal, leading to a cavity below, at the base of which a single cell is the germ of the future sporangium or spore- case. Upon this the spermatozoids, or spiral filaments of the an- theridia, act, one or more of them reaching it by finding their way down the canal of the pistillidium. Then this cell commences a special development, divides into two, and proceeds by ordinary cell- multiplication to build up the sporangium or capsule, in which a countless number of minute spores are produced. The spores of Mosses are formed in the same way as pollen-grains, which they much resemble in structure, being single cells with a double coat, of 29338 REPRODUCTION IN which the inner is the true cell-wall, and the outer a sort of secre- tion from it. In germination, the inner or proper membrane of the spore swells, and protrudes, from any part of its surface favorably situated, a tubular process, which forms partitions as it elongates and branches, giving rise to what has been fancifully named a pro- embryo, or, better, a prothallus, — a rudimentary plantlet very unlike a Moss, but closely resembling a branched Conferva, consisting, as it does, merely of ramified threads, or rows of cells. After a time _certain cells of its various branches, taking a special development, produce buds, which are soon covered with a tuft of rudimentary leaves, and grow up into the leafy stems of the perfected plant. Here a single spore—or rather a peculiar transitory plantlet developed from it — gives rise at once to a number of individuals. And in fecundation it is not the spores themselves that are fertilized, but a cell which by its development gives origin to a spore-case, and this to a vast number of spores.* 6G3. Fertilization of a Cell of a Prothallus, or peculiar germinating Plantlet, which thereupon develops into a Plant. This most extraordi- nary mode of fecundation has recently been discovered in the Ferns and other of the higher Cryptogamous orders. The fructification of Ferns consists of spore-cases alone, which are borne on the back, margins, or some other part of their leaves (Fig. 1287-1294), and are filled with spores resembling those of Mosses. Since Mosses have long been known to have organs answering in function to stamens, as ivell as those answering to pistils, and since Ferns are regarded as plants of higher rank than Mosses, their antheridia were diligent- ly sought for upon the fructifying plants, but in vain ; and botanists were therefore forced to the unwilling conclusion, that the highest organized of Cryptogamous plants were asexual. But antheridia, essentially like those of Mosses, have been at length detected, not upon the mature and fructifying plant, but upon the germinating plantlet. The germination of the spores of Ferns had long since been ob- served. The process begins in the same manner as in Mosses ; but the extremity of the tubular prolongation of the spore, converted by partitions into a row of cells, is developed into an expanded, leaf- like body (the pro-embryo, or prothallus as it is now called), which * The fullest account is by Hofmeister, Vergleichende Untersuchungen der Keimung, Entfaltmg, und Fruchtbildung Hoherer Kryptogamen, etc. — Lcipsic, 1851.CRYPTOGAMOUS OR FLOWERLESS PLANTS. 339 on a small scale resembles a frondose Liverwort. Upon this body, Migeli, in 1844, found moving spiral filaments, like those of’the an- theridia of Mosses, &c. This, as Henfrey remarks, “seemed to destroy all grounds for the assumption of distinct sexes, not only in the Ferns, but in the other Cryptogamia; for it was argued that the existence of these cellular organs producing moving spiral filaments (the so-called spermatozoa) upon the germinating fronds, proved that they were not to be regarded as in any way connected with the reproductive processes. But an essay published by the Count Suminski in 1848 totally changed the face of the question.” On the under side of the delicate, Marchantia-like, germinating frond, Suminski found a number of cellular organs of two distinct kinds, answering to antheridia and pistillidia. The former, which are the more numerous, are cells elevated on the surface of the germinating frond, in the cavity of which are formed other cells, filled with minute vesicles containing each a spiral filament coiled up in its in- terior. The organ bursts at its summit, and discharges the vesicles in a mucilaginous mass ; the spiral filaments moving within the vesicles at length make their way out of them and swim about in the water. These filaments, or spermatozoids, resemble those of Mosses, but "are flat and ribbon-like, as in Chara, and possess accord- ing to Suminski about six, according to Thuret numerous cilia, by whose vibrations they are moved. The pistillidia, if they may be so called, are rounded cavities in the cellular tissue of the same body, opening on the under side, in the bottom of which is a single glob- ular cell, from which the future growth proceeds. One or more of the active spermatic filaments, liberated by the bursting of the an- theridia, have been found to enter the open pistillidium, and to come to rest and then wither away in contact with this specialized cell. The latter now develops into a bud, or embryo, as it may perhaps be termed, which grows in the ordinary way, producing an abbrevi- ated axis, sending roots downward and leaf after leaf upwards ; and so producing the mature Fern.* And, as most Ferns are perennial plants, they produce year after year their fructification (consisting * The English reader is referred to Henfrey’s Translation of Mohl’s Anatomy and Physioloi/y of the Vegetable Cell; and Henfrey’s Report on the Reproduction and supposed Existence of Sexual Organs in the higher Cryptogamous Plants, in the Report of the British Association for the Advancement of Science, for 1851, reprinted in Silliman’s Journal, Yol. 14 and 15 ; from which the above account has been condensed.340 SPECIAL DIRECTIONS AND merely of spores in spore-eases), without any known limit, and with- out any other fecundation than that which occurred at first upon the germinating plantlet. 664. In Ferns, accordingly, it is not the sporangium that is fer- tilized, still less the spores, but a cell of a peculiar transitory plant- let formed by the germination of a spore. This cell otherwise will not develop at all; but when thus fecundated, it develops like a bud, and grows into a plant of indefinite longevity, capable of fructifying by a true parthenogenesis (571) throughout its long existence. This is also known to be the case with Equisetaceae; and the Lycopodia- cete or Club-Mosses and other vascular Cryptogamous Plants are thought to have analogous fecundation, although the details as yet are not well made out. CHAPTER XIII. OP THE SPONTANEOUS MOVEMENTS AND VITALITY OF PLANTS. 665. The facts brought to view in the preceding chapter, namely, that either the spores or the fertilizing corpuscles or filaments of most Cryptogamous plants of every order are temporarily endowed with motivity, naturally raises the inquiry whether such phenomena are altogether exceptional in the vegetable kingdom, or whether the power of executing movements is not a general endowment of plants as well as of animals, although in lesser degree. As we pass in re- view the various phenomena exhibited by plants in this respect, and at the same time consider that self-caused motion, internal or exter- nal, or the faculty of directing motion, is a necessary concomitant of life, we shall probably arrive at the conclusion, that this surprising activity of the microscopic spores and spermatozoids of Cryptogamous plants is not altogether anomalous, — that these are merely more vivid manifestations of a power which they share with ordinary vege- tables,— that plants are endowed with life no less really than ani- mals, —- that the distinction between plants and the lower animals in this respect is one of degree rather than of kind, — and that it is a «. characteristic of living things to move.SPONTANEOUS MOVEMENTS IN PLANTS. 341 666. The Special Directions which the parts of all plants assume are the result of self-caused movements, although such movements are mostly much too slow to be directly observed. Among these the most universal are the descent of the root in germination, the ascent of the stem into the light and air, and the turning of branches and the upper surface of leaves towards the light (120, 131, 294). These directions evidently are not the result of mere growth. It is not that the root grows downwards and the stem upwards ; but the root end of the elongating radicle bends or curves in the course of its growth so as to point downwards if not already in that position, and the other extremity, with the plumule, curves upwards, and the young stem, after reaching the light, if unequally illuminated, bends towards the stronger light. 667. Strenuous attempts have been made to explain these changes of direction upon mechanical principles. Mr. Knight thought that the descent of the root and the ascent of the stem were caused by gravitation ; and he seemed to show this by his celebrated experi- ments of removing germinating seeds from the influence of gravita- tion, and causing the root and stem to take a different direction in obedience to a different force. lie fixed some beans ready to ger- minate in a quantity of moss upon the circumference of a wheel, and made it to revolve vertically at a rapid rate ; replacing the effect of gravity by centrifugal force. On examination, after some days, the young root was found to have turned towards the circumference, and the stem towards the centre of the wheel. The same result took place when the wheel was made to revolve horizontally with con- siderable rapidity ; but when the velocity was moderate, the roots were directed obliquely downwards and outwards, and the stems obliquely upwards and inwards, in obedience both to the centrifugal force and the power of gravitation, acting at right angles to each other. It remained for Mr. Knight to explain how the same force, gravitation, could produce such opposite effects, causing the stem to ascend as well as the root to descend. This he ingeniously at- tributed to their different mode of growth. The root growing at its extremity only, he supposed that the soft substance of the growing jooint would be acted upon by gravity like an imperfect solid, and accumulated on the lower side; while the stem, growing by the elongation of an internode or a series of internodes already formed, its solid tissues would be unaffected by gravity, which could affect only its nutritive juices, causing their accumulation on the lower side of a 29*342 SPECIAL DIRECTIONS AND stem out of the perpendicular line; which side, thus more actively nourished, would grow more vigorously than the upper, and so cause the stem to turn upwards. To show how baseless this ingenious hypothesis is, we have only to remember, on the one hand, that the fluid contents of the cells of plants arrange themselves in obedience to other forces than gravity, and freely rise against its influence to the summit of the loftiest trees, so that gravity could establish no difference within the diameter of a germinating stem ; and on the other, that the root in germination, if fixed upon its surface, will pen- etrate a fluid of greater weight than itself, such as mercury. More- over, Schultz and Mohl have shoivi that, by careful management in reversing the ordinary conditions, — as by germinating seeds in damp moss, so arranged that the only light they could receive was reflected from a mirror, which threw the solar rays upon them directly from below, — the ordinary direction of the organs could be reversed, the roots turning upwards into the dark and damp moss, and the stems downward into the light. This would prove that light has more effect than gravitation, or any other imaginable influence of the mass of the earth. Yet, — what shows that there is some real relation between the direction assumed by the plant and the earth, — stems which grow in complete darkness always point to the zenith, as is seen in the shoots of vegetables in perfectly dark cellars, and in the elongated, constantly upright stemlet of germinating seeds too deeply buried to receive any light before they reach the surface of the soil. 668. The influence of a mass in some way analogous to attrac- tion is also observed in the germination of the Mistletoe. Its form- ing root turns regularly to the trunk or branch upon which it is parasitic, just as those of ordinary plants turn to the earth. And that it is the mass and not the quality of the body which determines the direction, is seen when germinating seeds of the Mistletoe are fixed close to the surface of a cannon-ball: all the roots as they grow point to its centre and advance to its surface, just as they do to the branch of a tree which they penetrate. 669. When the stem has emerged from the earth into the light of i day, this exerts a controlling influence over its direction. Young and green stems always tend to expose themselves as much as possi- ble to the light, and bend, very promptly when delicate, towards the' most illuminated side, as is well observed when plants are raised in an apartment lighted from a single aperture : and consequently in the open air, being equally illuminated on all sides, they grow up-SPONTANEOUS MOVEMENTS IN PLANTS. 343 right. De Candolle attempted a mechanical explanation of this bending of green stems towards the light, connecting it with assimi- lation and growth. He supposed that, as the side upon which the light strikes will fix most carbon by the decomposition of carbonic acid (34C - 348), so its tissue will solidify faster, and therefore elon- gate less, than the shaded side (which will become drawn, as the gardener terms it) ; and the stem or branch will necessarily bend towards the shorter or illuminated side. But when the light is equally diffused around a plant, the decomposition of carbonic acid will take place uniformly on all sides, and the perpendicular direc- tion naturally be maintained. Two facts at once demolish this in- genious theory. 1. It is now well known that, under the solar spectrum, the decomposition of carbonic acid in the green parts of plants is effected chiefly by the most luminous rays, that is, by yellow light, and next to this by orange and red; whereas the bending is strongest under the violet and blue rays, the yellow producing little curvature, and the red none at all. 2. When a stem curved under the light is split from the apex downwards, so as to separate the illuminated from the shaded side, the former curves more than be- fore, while the latter tends to straighten, — showing that it was pulled over by the contraction of the concave side, and not pushed over by its own greater growth. From all this it clearly appears that the turning of parts towards the light, and the other special directions of plants, are independent of growth, and apparently are effected by some inherent power. At least, they have thus far proved no more susceptible of mechanical explanation than the more marked movements of animals. 670. In leaves it is the denser and deeper green upper surface (262) that is presented to the light, while the paler lower surface, of looser tissue, avoids it. The recovery of the natural position, when the leaf is artificially reversed, is the more promptly effected in pro- portion to the difference in structure and hue between the two strata. This movement is so prompt in some plants, that their leaves follow the daily course of the sun. The leaf is more capable of executing such movements, on account of its extended surface, and its pliancy, and also on account of its usual attachment by an articulation. Here the slender vascular bundles oppose little resistance to lateral motion, while the soft and usually cellular enlargement favors it. Indeed, the efficient cause of the movement appears to be exerted here, and to be connected with the unequal tension or turgescence of344 SPECIAL DIRECTIONS AND the cells on the two sides. We might therefore expect more prompt and obvious changes of position in leaves than in stems. Familiar examples of the kind are met with in the altered nocturnal position of the leaves, &c. of many plants (often drooping, or folded as if in repose), which Linnfeus designated by the fanciful name of C71. TllC Sleep of Plants. This is well seen in the foliage of the Locust and of most Leguminous plants, and in those of Oxalis, or Wood-Sorrel. It is most striking in the leaflets of compound leaves. The nocturnal position is various in different species, but uniform in the same species, showing that the phenomenon is not mechanical. Nor is it a passive state, for, instead of drooping, as do those of the common Locust-tree, the leaflets are very commonly turned upwards, as those of Honey-Locust, or upwards and forwards, as in the Sensi- tive-Plant, contrary to the position into which they would fall from i their own weight. De Candolle found that most plants could be I made to acknowledge an artificial day and night, by keeping them in , darkness during the day, and by illuminating artificially at night j The sensibility to light appears to reside in the petiole, and not in I the blade of the leaf or leaflet; for these movements are similarly t executed, when nearly the whole surface of the latter is cut away. 672. The leaves of the blossom also assume various positions, according to the intensity and duration of the light. Many expand their blossoms in the morning and close them towards evening, never to be opened again, as those of Cistus, Portulaea, and Spider- wort ; while others, like the Crocus, close when the sun is with- drawn, but expand again the following morning. On the other hand, the Evening Primrose, Silene noctiflora, &c. unfold their petals at twilight, and close at sunrise. The White Water-Lily (Nymplnea) expands in the full light of day, but uniformly closes near the mid- dle of the afternoon, and is then usually withdrawn beneath the sur- face of the water. The Morning-Glory opens at the dawn ; the Lettuce, and most Cichoraceous plants, a few hours later, but close under the noonday sun ; the Mirabilis is called Four-o’clock, because opening nearly at that hour in the afternoon, and it closes the next morning; and so of other species,— each having its own hour or amount of light in which its blossoms open or close. Berthelot men- tions an Acacia at Teneriffe, whose leaflets regularly close at sunset and unfold at sunrise, while its flowers close at sunrise and unfold at sunset. Although these movements, both in leaves and blossoms, are undoubtedly dependent on the light, they are by no means directlySPONTANEOUS MOVEMENTS IN PLANTS. 345 governed by it. The so-called sleep of the common Sensitive Plant, for instance, begins just before sunset, but its waking frequently pre- cedes the dawn of day ; showing that it is not the mere amount of the light which governs the position, in the manner of a mechanical power.* C73. Sensible Movements from Irritation. All the changes of posi- tion already described — like those of the hands of a clock or of the shadow on a dial — are too slow for the motion to be directly seen. But a greater exaltation apparently of this common faculty is observed in the leaflets of various Leguminous plants, especially of the Mimosa tribe, which, when roughly touched, assume their peculiar nocturnal position, or one like it, by a visible and sometimes a rapid movement. The Sensitive Plant of the gardens (Mimosa pudica) is a familiar instance of the kind, suddenly changing the position of its leaflets on being touched or jarred, and applying them one over the other close upon the secondary petiole ; if more strongly irritated, the secondary petioles also bend forward and approach each other, and the general petiole itself sinks by a bend- ing at the articulation with the stem. Similar although less vivid irritability is shown by the Mimosa strigillosa and the Schrankia of the Southern States, where the leaflets promptly fold up when brushed with the hand. The most remarkable instance of the kind, however, is presented by another native plant of the United States, the Diomea muscipula, or Venus’s Fly-trap (Fig. 297, 298); in which the touch even of an insect, alighting upon the upper surface of the outspread lamina, causes its sides to close suddenly, the strong bristles of the marginal fringe crossing each other like the teeth of a steel-trap, and the two surfaces pressing together with considerable force, so as to retain, if not to destroy, the intruder, whose struggles only increase the pressure which this animated trap exerts. This most extraordinary plant abounds in the damp, sandy savannas in the neighborhood of Cape Fear River, from Wilmington to Fayette- * The odors of flowers, also, arc sometimes given off continually, as in the Orange and the Violet, or flowers may nearly lose their fragrance during the heat of mid-day, as in most cases; while others, such as Pelargonium triste, Hcsperis tristis, and most dingy flowers, which are almost scentless during the day, ex- hale a powerful fragrance at night. The night-flow'ering Cereus grandiflorus 1 emits its powerful fragrance at intervals; sudden emanations of odor being given off about every quarter of an hour, during the brief period of the expan-1 sion of the flower.346 SPONTANEOUS MOVEMENTS IN PLANTS. ville, North Carolina, where it is exceedingly abundant; but it is not elsewhere found. 674. A familiar, although less striking, instance of the same kind is seen in the stamens of the common Barberry, which are so excit- able, that the filament approaches the pistil with a sudden jerk, when touched with a point, or brushed by an insect, near the base on the inner side. The object of this motion seems plainly to be the dis- lodgement of the pollen from the cells of the anther, and its projec- tion upon the stigma. But in the Diontea it is difficult to conceive what end is subserved by the capture of insects. In a species of Stylidium of New Holland, not uncommon in conservatories, the column, consisting of the united stamens and styles, is bent over to one side of the corolla; but if slightly irritated, it instantly springs over to the opposite side of the flower. These are among the more remarkable cases of the kind, but by no means the only ones. Anatomical investigation brings to view no peculiarity in the struc- ture of such plants which might explain these movements. Some other movements, which have been likened to these, are entirely mechanical; as that of the stamens of Ivalmia, where the ten an- thers are in the bud received into as many pouches of the mono- petalous corolla, and are carried outwards and downwards when the corolla expands. In this way the slender filaments are strongly re- curved, like so many springs ; until at length, when the anthers are liberated by the full expansion of the corolla, or by the touch of a large insect or other extraneous body, they fly upwards elastically, projecting a mass of pollen in the direction of the stigma. 075. The twining of stems round a support, and the coiling of tendrils, are attributed by Mold to a dull irritability; and this is the most plausible explanation that has been offered. The inner side, which becomes concave and has smaller cells, is in this, as in other cases, the irritable portion. When a foreign body is reached, a contraction of this side causes the tendril partially to embrace the support: this brings the portion just above into contact with it, which is in like manner incited to curve; and so the hold is secured, or the twining stem continues to wind around the support. In ten- drils this irritability, propagated downward along the concave side, would appear to cause its contraction, which throws the whole into a spiral coil, or, when fixed at both ends, into two opposite spiral coils, thus approximating the growing stem to the supporting body.SPONTANEOUS MOVEMENTS IN PLANTS. 347 67 6. In all these cases, -whether of slow or rapid change of posi- tion, the immediate cause of the movement, however incited, must be either the shortening of the cells on the concave side, or their elongation on the convex side. The fact that stems curved towards the light tend to curve still more when the convex side is cut away (669) points to a contraction of the cells on the concave side as the cause of the curvature. The elastically bursting pods of the Balstun or Touch-me-not (Impatiens), &c. confirm this view. Here the valves of the capsule curve inwards very strongly when liber- ated in dehiscence; and that this is owing to the shortening of the cells of the inner layer, and not to the enlargement or turgescence of those of the thick outer layer, is readily shown by gently paring away the whole outer portion before dehiscence ; for the inner layer when liberated still incurves and rolls itself up as strongly as before. The short valves at the summit of the pod of Echinocystis slowly curve outwards in dehiscence ; here the cells of the outer layer of the valve are longer and narrower than those of the inner, and the latter are stretched and torn in opening; so that here the con- traction of the cells on the side which becomes concave is undoubt- edly the cause of the movement. And since muscular movements are effected by the contraction of the cells which, placed end to end, compose a muscular fibril, we may suspect that vital movements generally, both in vegetables and in animals, are so far analogous, that they are brought about in the same general way, viz. by the shortening of cells. Even the opening and closing of the stomata of the leaves (268) appear to be controlled by the vital force, and to be effected by a self-caused change in the form of the guardian cells. How the light, or external irritation, or any other influence, acts in inciting this change of form of the cells of some part of a plant, we know no more, and no less, than we know how a nerve, or an electrical current, acts upon a muscle of an animal to bring about the contraction or change of shape of its component cells. If animals make 677. Spontaneous or Automatic Movements, so also do some plants execute brisk and repeated movements irrespective of extraneous force, or even of extraneous excitation, and which, indeed, are ar- rested by the touch. An instance of such spontaneous and contin- ued motion, of the most remarkable kind, is furnished by the trifoli- olate leaves of Desmodium gyrans, an East-Indian Leguminous plant. The terminal leaflet does not move, except to change from the348 SPONTANEOUS MOVEMENTS IN PLANTS. diurnal to the nocturnal position, and the contrary; but the lateral ones are continually rising and falling, both day and night, by a suc- cession of little jerks, like the second-hand of a time-keeper; the one rising while the other falls. Exposure to cold, or cold water poured upon the plant, stops the motion, which is immediately re- newed by warmth. The late Dr. Baldwin is said by Nuttall to have witnessed the same thing in our own Desmodium cuspidatum, in Georgia; but the observation has never been confirmed. In several tropical Orchideous plants, and especially in a species of Megac.linium, the lower petal, or labellum, executes similar spontane- ous movements, with great freedom and pertinacity. Such phenom- ena, occurring as they do in Phamogamous plants of ordinary struc- ture may serve to render more credible the true vegetable character of the 678. Free Movements of tlic Spores of Algae, and the cor- puscles or spiral filaments of the antheridia of most Cryp- togamous plants, already re- ferred to (059 - G63). The spores of most of the lower Algai are now known to ex- hibit this peculiar activity at the time of their discharge from the parent cell, when, for some moments, or usual- ly for several hours, they behave like infusory ani- mals, executing spontaneous movements in the water, until they are about to ger- minate. This singular move- ment was first detected many years ago in Yaucheria 639 640 611 612 C43 FIG. 636. Fruiting end of a plant of Yaucheria geminata (after Thuret); one of the branches still containing its spore. 637- Moving spore just escaped from the apex of the other branch ; the ciliary apparatus seen over the whole surface. 638. Spore in germination. FIG. 639-642. Successive steps in the germination of (Edogonium (Conferva) vesicata. 643. The plant developed into a series of cells, four of which display the successive steps in the formation of a spore. 644. The locomotive spore with its vibratile cilia (copied from Thuret). When the movement ceases, and it begins to germinate, it appears as in 639. (The antheridia or fertilizing apparatus of these plants were not known when these figures were made.)SPONTANEOUS MOVEMENTS IN PLANTS. 349 (Fig. 89, 636). Immediately on its discharge from the mother plant the spore begins to move freely in the water, and continues to do so for some hours, when it fixes itself and begins to grow (Fig. 638). Its movements, moreover, like those of the antheridial fila- ments or corpuscles, may be enfeebled or arrested by the application of a weak solution of opium or chloroform. Through these means it has been ascertained that they are caused by the vibrations of minute cilia which cover the surface, which are rendered visible by thus enfeebling their movement, and which exhibit the closest resemblance to the vibratile cilia of animals, especially those of the polygastric animalcules. In the Conferva tribe generally the vibra- tile cilia occupy one end of the spore, and are in some cases numer- ous (as in Fig. 644), in others only two or three in number. The spores are small, and of about the same specific gravity as the water in which they live, so that a slight force suffices to propel them. 679. locomotion of Adult Microscopic Plants. The spores ofYau- cheria and the like, becoming quiescent before germination, grow into fixed thread-like plants of considerable size, endowed with no greater degree of motivity than ordinary vegetables. A multitude of still simpler Algae, however, swarm in every pool or stream, SO’ minute in size as to be individually totally invisible to the naked eye (most of them when full grown are very much smaller than the spores of Vaucheria, &e.) ; and these are endowed, even at maturity, with such powers of locomotion that their vegetable character, although now well made out, was long in question on this account alone. Of this kind are the various species of Oscillaria (Fig. 84), so named from the writhing movement they exhibit, the Desmidi- aceat, to which Closterium (Fig. 631) belongs, and the nearly allied Diatomacere, — the lowest, minutest, and the most freely moving of plants, but clearly members of the vegetable kingdom notwithstanding. These execute free movements of translation, in some cases slow, in others rapid; but the mechanism of the' motion is still unknown. 680. Not only, therefore, do plants generally manifest impressi- bility or sensitiveness to external agents, and execute more or less decided, though slow, movements; but many species of the higher grades exhibit certain vivid motions, either spontaneous or in conse- quence of extraneous irritation ; while the lowest tribes of aquatic plants, as they diminish in size and in complexity of organization, habitually execute, at some period at least, varied spontaneous move- 30350 SPONTANEOUS MOVEMENTS IN PLANTS. ments, which we are unable to distinguish in character from those of the lowest animals. It is at their lowest confines, accordingly, that the vegetable and the animal kingdoms approach or meet, and even seem to blend their characters. 681. When we consider that the excitability of sensitive plants is often transmitted, as if by a sort of sympathy, from one part to another; that it is soon exhausted by repeated excitation (as is certainly the case in Dionaea, the Sensitive-Plant, &c.), to be re- newed only after a period of repose; that all plants require a season of repose ; that they consume their products and evolve heat under special circumstances with the same results as in the animal kingdom (Chap. VII.) ; that, as if by a kind of instinct, the various organs of the vegetable assume the positions or the directions most favorable to the proper exercise of their functions and the supply of their wants, to this end surmounting intervening obstacles; when we consider in this connection the still more striking cases of spon- taneous motion that the lower Algte exhibit; and that all these motions are arrested by narcotics, or other poisons, — the narcotic and acrid poisons even producing effects upon vegetables respectively analogous to their different effects upon the animal economy; we cannot avoid attributing to plants a vitality and a power of “ making movements tending to a determinate end,” not different in nature, perhaps, from those of the lowest animals. Probably life is essen- tially the same in the two kingdoms ; and to vegetable life faculties are superadded in the lower animals, some of which are here and there not indistinctly foreshadowed in plants. 682. The essential differences between plants and animals were enumerated at the commencement of this work (16), and have been illustrated in its progress. Distinct as are the general structure and the offices of the two great kinds of organized beings, it is still I doubtful whether the discrimination is absolute, or whether the functions of the vegetable and the animal may not, in some micro- scopic organisms, be imposed upon the same individual.PART II. SYSTEMATIC BOTANY. 683. In the preceding chapters plants have been considered in view of their structure and action. And when different plants have been referred to and their diversities noticed, it has been in eluci- dation of their morphology, — of the exuberantly varied forms or modifications under which the simple common plan of vegetation is worked out, as it were, in rich detail. The vegetable kingdom, that is, vegetation taken as a great whole, presents to our view an im- mense number of different kinds of plants, more or less resembling each other, more or less nearly related to each other. It is the object of Systematic Botany to treat of plants as members of a system, or orderly parts of a whole, — and therefore to consider them as to their kinds, marked by differences and resemblances, and to contemplate the relations which the kinds, or individual members of the great whole, sustain to each other. To this end the botanist classifies them, so as to exhibit their relationships, or degrees of resemblance, and expresses these in a systematic arrangement or classification, — designates them by appropriate appellations, and distinguishes them by clear and precise descriptions in scientific lan- guage ; so that not only may the name and place in the system, the known properties, and the whole history of any given plant, be read- ily and surely obtained by the learner, but likewise an interesting view may be obtained of the general scheme or plan of the Cre- ator in the Vegetable World. 684. Our present endeavor will be to explain the general prin- ciples of natural-history classification, and the foundation, or facts in nature, upon which it rests, and then cursorily to show how these are applied to the actual arrangement of the known species of plants.352 PRINCIPLES OF CLASSIFICATION. CHAPTER I. OF THE PRINCIPLES OF CLASSIFICATION. 685. Plants and animals — the members of the organic king- doms of nature — exist as individuals (13), of definite kinds, each endowed with the characteristic power of producing like individuals and so of continuing the succession. The different sorts (1.) are re- produced true to their essential characteristics from generation to generation ; and (2.) they exhibit unequal and very various degrees of resemblance or of dissimilarity among themselves. These simple propositions lie at the foundation of all classification and system in natural history. Upon the first rests the idea of species; upon the second that of genera, orders, and all groups higher than species. 686. Individuals. The idea of individuality is derived from man and ordinary animals, and thence naturally extended to vegetables. Individuals are beings, owing their existence and their characteris- tics to similar antecedent beings, and composed of parts which together constitute an independent whole, indivisible except by mu- tilation. Individuality is perfectly exemplified in all the higher and most of the lower animals, which multiply by sexual propagation only, and in which the offspring, or the ovum, early separates from the parent; but it is incompletely realized in those animals of the lower grade which are propagated by buds or offshoots as well as by ova, and where, the offspring may remain more or less intimately connected with the parent. Still more is this so in plants, which in every grade are or may be propagated by buds or offshoots; which in vegetation develop an indefinite number of similar parts ; which produce branches like the parent plant, and capable either of continuing to grow in connection with it, or of becoming independent (232). The individual plant, therefore, is evidently not a simple and true individual in the proper sense of the word, — in the sense that an ordinary animal is. A kind of social or corporate individu- ality in the complex radiated animals often gives a certain limita- tion and shape to the congeries or polypidom, and in many of them even subordinates certain parts to the common whole, assigning to them special functions for the common weal: and this-is universally and more strikingly the case with plants, except the very simplest.INDIVIDUALS. 353 So that for practical purposes, and in a loose, general sense, we take the whole plant as an individual, so long as it forms one con- nected mass, and no longer. But in a philosophical view we cannot well regard this congeries as the true vegetable individual. 687. Accordingly many botanists (of whom are Thouars at the beginning of the present century, and Braun * at the present day) regard as the true individual the shoot, or simple axis with its foli- age, &c., whether this be the primary stem with its roots implanted in the soil, or a branch implanted on the stem. This view simpli- fies our conception of a vegetable, but is itself open to all the objec- tions it raises against the individuality of the plant as a whole. For just as the herb, shrub, or tree is divisible into shoots or series of similar axes, so the shoot is divisible into similar component parts, or phytons (163), indefinitely repeated, and which may equally give rise to independent plants. Those philosophical naturalists, there- fore, who find no stable ground in this position, are forced towards one of two opposite extremes. Some, justly viewing sexual repro- duction as of the highest import, are led to regard the whole vege- tative product of a seed as theoretically constituting one individual, whether the successive growths remain united, or whether they form a thousand or a million of vegetables, as may often happen. Ac- cording to this view, all the Weeping-Willow trees of this country are parts of one individual; and most of our Potato plants must be- long to one multitudinous individual, while others wholly similar, but freshly grown from seed, are- each individuals of themselves ; — a view which apparently amounts to an absurdity in terms and in fact. Others, following out the idea mentioned above, and laying the main stress upon simplicity and indivisibility, rather than upon tendency to separation, regard the phyton in ordinary plants, and the cell in those of lowest grade, as on the whole best answering, in the vege- table kingdom, to the simple individual in the animal. But this is merely a question of greater or less analogy. For the individual, in the proper sense of the term, is more or less confluent into a vegeta- tive cycle in all plants, and in many of the lower animals, and attains full realization only in the higher grades of organized existence. * See his elaborate treatise, On the. Vegetable. Individual in its Relation to Species (of which a translation from the German, by C. F. Stone, was published in the American Journal of Science and the Arts, vols. 19 and 20, 1855), for the com- plotest development of this view, and for the history of the subject generally. 30*354 PRINCIPLES OE CLASSIFICATION. 688. But, whatever it may be which we practically or philosophi- cally regard as the vegetable individual, it is evident that plants as well as animals occur in a continued succession of organisms or beings which stand in the relation of parent and offspring. Each particular sort is a chain, of which the individuals are the links. To this chain, or (as expressed by Linnasus) this perennial succes- sion of individuals, the natural-historian applies the name of 689. Species (Id). Every one knows that the several sorts of plants and animals steadily reproduce themselves, or, in other words, keep up a succession of essentially similar individuals, and under favorable circumstances increase their numbers. Each particular kind of cultivated plant or domesticated animal is represented before our eyes in a mass of individuals, which we know from observation to a certain extent, and from necessary inference, have sprung from the same stock. And common observation has led people everywhere to expect that the different sorts will continue true to their kind, or at least to conclude that the different sorts of plants or of animals do not shade off one into another by insensible grada- tions, like the colors of the rainbow, as would have been the case if there were not distinct kinds at the beginning, and if their distinc- tions were not kept up, unmingled, and transmitted essentially un- altered, from generation to generation. So we naturally assume that the Creator established a definite, although a vast, number of types or sorts of plants and animals, and endowed them with the faculty of propagation each after its kind; and that these have so continued unchanged in all their essential characteristics. Out of these gen- eral observations and conceptions the idea of species must have origi- nated ; from them we deduce its scientific definition. Namely, that the species is, abstractly, the type or original of each sort of plant, or animal, thus represented in time by a perennial succession of like individuals, or, concretely, that it is the sum of such series or con- geries of individuals; and that all the descendants of the same stock, and of no other, compose one species. And, conversely, as we can never trace back the genealogy far, we naturally infer community of origin from fraternal resemblance; that is, we refer to the same species those individuals which are as much alike as those are which we know to have sprung from the same stock.* * We use the word stock advisedly, (and in one of its proper meanings, that of the original or originals of a lineage,) to avoid the assertion or denial of theSPECIES AND VARIETIES. 355 690. Specific identity is not of course inferred from every strongly marked resemblance; for the resemblance may be only that of genus, and individuals so related are inferred not to have had a common origin. Nor is it denied on account of every difference; for individu- als of the same stock may differ considerably; in fact, no two plants are exactly alike, any more than two men are. Such differences when they become distinctly marked give rise to 691. Varieties. If two seeds from the same pod are sown in dif- ferent soils, and submitted to different conditions as respects heat, light, and moisture, the plants that spring from them will show marks of this different treatment in their appearance. Such differ- ences are continually arising in the natural course of things, and to produce and increase them artificially is one of the objects of culti- vation. Such variations in nature are transient; the plant often outlasting the cause or outgrowing its influence, or else perishing from the continued and graver operation of the modifying influ- ences. But in the more marked varieties which alone deserve the name, the cause of the deviation is occult and constitutional; the deviation occurs we know not why, and continues throughout the existence and growth of the herb, shrub, or tree, and consequently through all that proceeds from it by propagation from buds, as by off- sets, layers, cuttings, grafts, &c. In this way choice varieties of Ap- ples, Pears, Potatoes, and the like, are multiplied and perpetuated. 692. Since the progeny inherits or tends to inherit all the char- acters and properties of the parent, constitutional varieties must have a tendency to be reproduced by seed, —• a tendency which might often prevail, within certain limits, over that general influence which would remand the variety to the normal state, were it not for the commingling which so commonly occurs in nature, through the cas- ual fertilization of the ovules of one individual by the pollen of other individuals of the same species. By assiduously pursuing the oppo- origin of each species from a single individual or a single pair, — a question which science does not furnish grounds for deciding. It is evidently more simple to assume the single origin, where there is no presumption to the con- trary, as there may be in the case of tricecious or of organically associated plants or animals ; but the contrary supposition does not affect our idea of species, if" we suppose the originals to have been as much alike as individuals proceeding from the same parent are, and to have had a common birthplace. The investi-1 gation of the geographical distribution of plants more and more favors the ideal of the dissemination of each species from a centre of its own.356 PRINCIPLES OP CLASSIFICATION. site course in domesticated plants, that is, by constantly insuring the fertilization of the ovules of a marked variety by the pollen of the same, and by saving seed only from such of the resulting progeny as possess the desired peculiarity in the highest degree, and so on for several generations, it would appear that 693. Races, viz. varieties whose characteristics are transmissible by seed with considerable certainty, may generally be produced. Of this kind are the particular sorts of Indian Corn, Rye, Cabbage, Lettuce, Radishes, &c., and indeed of nearly all our varieties of culti- vated annual and biennial esculent plants, as well as of several per- ennials, many of which have been fixed through centuries of domes- tication. j^What is now taking place with the Reach in this country 'may convince us that races may be developed in trees as well as in herbs, and in the same manner; and that the reason why most of our cultivated races are annuals or biennials is because these can > be perpetuated in no other way, and because the desired result I is obtainable in fewer years than in shrubs or trees. Although races hardly exist independently of man, he cannot be said to origi- nate their peculiarities, nor is it known how they originate. The sports, as the gardener calls them, appear as it were accidentally in cultivated plants. The cultivator merely selects the most promis- ing sorts for preservation, leaving the others to their fate. By par- ticular care he develops the characteristic feature, and strengthens and fixes, in the manner already explained, the tendency to become hereditary, so securing the transmissibility of the variety as long as he takes sufficient care of it. If not duly cared for, they dwindle and lose their peculiarities, or else perish ; if allowed to mix with normal forms, they revert to the common state of the species. Were culti- vation to cease, all these valued products of man’s care and skill would doubtless speedily disappear; the greater part, perhaps, would perish outright; the remainder would revert, in a few generations of spontaneous growth, to the character of the primitive stock. 691. Although man has no power to create the peculiarities of such varieties, he may manage so as not only largely to increase them, but also to combine the peculiarities of widely different varie- ties of a species, and thereby produce novel results. This is effected ’by Cross-breeding, i. e. by fertilizing the pistil of one variety with the pollen of another variety of the same species. In this way most esteemed new varieties of flowers and fruits are originated, which combine the separate excellences of both parents. The cultivatorRACES, HYBRIDS, ETC. 357 often proceeds one step farther, in certain cases, and gives rise to a different kind of cross-breeds, viz. 695. Hybrids. These are cross-breeds from different but nearly related species. It is well known that, by proper precautions, the pistil of a flower of one species may often be fertilized by the pollen of another of a similar constitution, and that the plants raised from the seeds so produced combine the characters and properties of both parents. Some kinds, such as Azaleas and Pelargoniums, hy- bridize very readily; in others hybridism is effected with difficulty between nearly related species. The gardener produces hybrids among most of his favorite plants, and variously cross-breeds and mingles them, so as to confuse the limits of many cultivated species. But in nature hybrids rarely occur. Not more than fifty wild kinds are clearly known as of continued or frequent occurrence. Others may perhaps be originated from time to time ; but their existence is transient. (For hybrids are generally, if not always, sterile, and! therefore incapable of perpetuation by seed-J But their ovules may j be fertilized by the pollen of either of their parents, when the progeny reverts to that species, probably retaining, however, some traces of the mixture, unless this should be obliterated by successive fertilizations from individuals of the same parent species. It is probable that cross-fertilization between different individuals of the same species is more common than is generally supposed, and that it is one of Nature’s means for repressing variation. On the other hand, continued self-fertilization (or breeding in and in) is almost sure to perpetuate, as well as farther to develop, individual peculiari- ties, i. e. those of variety or race. 696. However plants may be modified by art and man’s device, the systematic botanist proceeds upon the ground that the distinc- tions between species, whether small or great, are real, and in nature are permanent, — that variation, wide as it may be, is naturally re- stricted within certain limits. And this appears to be true. As dis- tinctions subordinate to species are in nature both indefinite and transitory, these, however important to the cultivator, are of little account with the systematic botanist. 697. Species are the true subjects of classification. And the end and aim of systematic botany is to ascertain and to express their relationship to each other. The whole ground in nature for the classification of species is the obvious fact that species resemble or differ from each other unequally and in extremely various de- ■358 PRINCIPLES OF CLASSIFICATION. grees, If this were not so, or if related species differed one from another by a constant quantity, so that, when arranged according to their resemblances, the first differed from the second about as much as the second from the third, and the third from the fourth, and so on throughout, — then, with all the diversity in the vege- table kingdom there actually is, there could be no natural founda- tion for their classification. The multitude of species would render it necessary to classify them, but the classification would be wholly artificial and arbitrary. The actual constitution of the vegetable kingdom, however, as appears from observation, is, that some species resemble each other very closely indeed, others differ as widely as possible, and between these the most numerous and the most various grades of resemblance or difference are presented, but always with a manifest tendency to compose groups or associations of resembling specie-, — groups the more numerous and apparently the less defi- nite in proportion to the number and the nearness of the points of resemblance. These various associations the naturalist endeavors to express, as far as is necessary or practicable, by a series of generali- zations, —- of which the lower or particular are included in the higher, — based on the more striking, or what he deems the most important (i. e. the most definite or least exceptional) points of re- semblance of several grades. Linnams and the naturalists of his day mainly recognized three grades of association, or groups supe- rior to species, viz. the genus, the order, and the class ; and these are still the principal members of classification. Of these 698. Genera (plural of Genus) are the more particular or special groups of related species. They are groups of species which are most alike in all or most respects, — which are constructed, so to say, upon the same particular model, with only circumstantial dif- ferences in the details. They are not necessarily nor generally the lowest definable groups of species, but are the lowest most clearly definable groups which the botanist recognizes and accounts worthy to bear the generic name ; for the name of the genus with that of the species added to it is the scientific appellation of the plant or animal. Constituted as the vegetable and animal kingdoms are, the recognition of genera, or groups of kindred species, is as natural an operation of the mind as is the conception of species from the asso- ciation of like individuals. This is because many genera are so strongly marked, or at least appear to be so, as far as ordinary ob- servation extends. Every one knows the Rose genus, composed ofGENERA AND ORDERS. 359 the various species of Roses and Sweetbriers ; the Bramble genus, comprising Raspberries, &c., is popularly distinguished to a cer- tain extent; the Oak genus is distinguished from the Chestnut and the Beech genus, &c.: each is a group of species whose mutual resemblance is greater than that of any one of them to any other plant. The number of species in such a group is immaterial, and in fact is very diverse. A genus may be represented by a single known species, when its peculiarities are equivalent in degree to those which characterize other genera, — a case which often occurs ; although if this were generally so, genus and species would be equivalent terms. If only one species of Oak were known, the Oak genus would have been as explicitly discerned as it is now that the species amount to two hundred; it would have been equally distin- guished by its acom and cup from the Chestnut, Beech, Hazel, &c. Familiar illustrations of genera in the animal kingdom are furnished by the Cat kind, to which belong the domestic Cat, the Catamount, the Panther, the Lion, the Tiger, the Leopard, &c.; and by the Dog kind, which includes with the Dog the different species of Foxes and Wolves, the Jackal, &c. The languages of the most barbarous people show that they have recognized such groups. Naturalists merely give to them a greater degree of precision, and indicate what the points of agreement are. 699. If all such groups were as definite and as conspicuously marked out as those from which illustrations are generally taken, genera might be as natural as species. But unfortunately the pure- ly popular genera are comparatively few, and although often cor- rectly founded by the unscientific, yet they are as frequently wrongly limited, or based upon fanciful resemblances. Popular nomencla- ture, embodying the common ideas of people, merely shows that generic groups are recognizable in a considerable number of cases, but not that the whole vegetable or the whole animal kingdom is divisible into a definite number of such groups of equally or some- what equally related species. Whether this proves to be so or not, and whether genera are actually limited groups throughout, this is not the place to consider. Suffice it to say, that there is a ground in nature for genera, and that the naturalist is obliged to treat them, for systematic purposes, as strictly definite groups of species. While genera represent the closer relationships of species, 700. Orders or Families (as they are interchangeably called in botany) express remoter relationships or more general resemblances.3 GO PRINCIPLES OF CLASSIFICATION. They are groups of kindred genera, or rather genera of a higher grade. For example, Oaks, Chestnuts, Beeches, Hazels, and Horn- beams constitute so many genera, which, although quite distinct, have so strong a family likeness, and are so much alike in their general structure and properties, that they are associated into one order or family group (the Oak family) ; while the Birches and the Alders form another order not very different in character, and the Walnuts and Hickories another. So the Pines, Firs or Spruces, Larches, Cedars, &c., obviously related among themselves so mucli more than they are to any other genera, are niembers of the Pine family; the Raspberry, Blackberry, and Strawberry, with many others, are as- sociated with the Rose in the Rose family; and so on. 701. Classes are to orders what these are to genera. They ex- press more extensive, or the most extensive relations of species, each class embracing all those species which are framed upon the same general plan of structure, however differently that plan may be carried out in particulars. Thus all Exogenous or Dicotyledonous plants constitute one class, their stems, their embryo, their leaves, &c. being constructed upon the same general plan in all the species, while Endogenous or Moncotyledonous plants for the same reasons compose another class. 702. The sequence of groups, rising from particular to universal, is Species, Genus, Order, Class ; or, in descending from the univer- sal to the particular, Class, Order, Genus, Species. 703. These are the common framework of all methods of classifi- cation, both in the animal and the vegetable kingdoms. But these do not exhaust our powers of analysis, nor express all the gradations which we may observe in the relationship of species. They merely gather up what are deemed the most essential indications of re- lationship, and express them under three grades superior to species, which always carry with them distinctive names. But a more elab- orate analysis is often requisite, on account of the large number of objects to be arranged, and the various degrees of relationship which may come into view. And these, when needful, are expressed in a series of intermediate groups or divisions, which may or may not require distinctive names. Names for them are, however, aORDERS, CLASSES, AND THEIR SUBDIVISIONS. 361 great convenience, especially for those which are most natural and definite. For some of these intermediate groups may be as dis- tinctly marked as are those which ive call genera or orders. 704. The great advantages and proper use of this intermediate grouping are, that it secures all the benefits of complete analysis without undue multiplication of genera and orders, and that, by ex- tending the scale, more grades of relationship may be noted, and the whole expressed in our systems in truer perspective. Accordingly, when groups of species below what we take for genera are recog- nized, and found to be so well marked that by a little lowering of the scale they would be received as genera, they are denominated Subgenera. If less definite, we term them merely Sections. For example, Pyrns, the Pear genus, embraces Apples, Pears, Crab- apples and the like ; and the Pear itself is the type or normal rep- resentative. From this the Apple and the several species of Crab- apple differ considerably, but not quite enough to warrant generic separation: they are therefore recognized as forming a subgenus, Mains, of the genus Pyrus. Again, the Bramble genus, Ruins, com- prises both Raspberries and Blackberries, which, although distin- guished by everybody, are not so much or so definitely different from each other as Apples and Crab-apples are from Pears; so they are ranked merely as sections of the Bramble genus. If we were to receive all such particular groups of species as genera, and give them substantive names, as many naturalists are doing, the nicer grada- tions of affinity would be disregarded, while genera would be reck- oned by tens of thousands ; at length half our species wrnuld become genera with substantive names, and the whole advantage of classifi- cation and nomenclature would be lost. The proper discrimination of genera is the real test of a naturalist. 705. When groups intermediate between genera and orders are admitted, they are generally denominated Tribes, and their divis- ions, if any, Subtribes. But the highest divisions of orders, when marked by characters of such importance that it might fairly be questioned whether they ought not to be received as independent orders, take the name of Suborders. For example, the great Rose family, as we receive it, embraces three suborders ; one of them represented by the Plum, Peach, Almond, &c.; a second, by the Pear, Quince, Hawthorn, and the like ; and the third, by the Rose itself and its immediate relatives. Some botanists receive these three as so many orders : we regard them as suborders, be- 31362 PRINCIPLES OF CLASSIFICATION. cause of the strong family likeness which pervades the whole, and of the transitions between them. In the larger of these suborders, or the proper Rose family, we recognize three tribes: one repre- sented by the Rose genus itself; one by the Bramble genus, with the Strawberry, Cinquefoil, Avens, &c.; and the third by Spiraea and its near relations. And, again, the second and larger of these embraces genera which are different enough to be ranked under several subtribes. 706. Upon the same principles, groups may be interposed between the orders and the classes, of which the highest kind will take the name of Subclasses. And even above classes we have the most comprehensive division of all plants into a higher and a lower grade or Series (98) ; which brings us up to the vegetable Kingdom, one of the three great departments of Nature. 707. To exhibit the whole sequence or stages of natural-history classification, so that the student may see the relative rank of groups, designated by the terms which have now been explained, they are here presented, arranged in a descending series, beginning with the primary division of natural objects into kingdoms, and indicating by small capitals those of fundamental importance and universal use in classification. Kingdoms, Series, Classes, Subclasses, Orders or Families, Suborders, Tribes, Subtribes, Genera, Subgenera, Species, Varieties, Individuals. 708. Characters. An enumeration of the distinguishing marks, or points of difference between one class or order, &c. and the others, is termed its character. Characters accordingly properly embrace only those points which are common to all plants of the group, but not to the other groups of the same rank. The characters of classes, &c. are restricted to those general peculiarities of structure upon which these great groups are established : the ordinal charac- ter recites the particulars in which the plants it comprises differCHARACTERS.-BINOMIAL NOMENCLATURE. 363 from all others of the class the generic character enumerates those points which distinguish the plants of the genus in question from all others of the same order or suborder; the specific character indicates the differences between species of the same genus ; — to which in botanical works more or less of general description, accord- ing to the plan and extent of the work, is generally added. 709. A complete system of Botany will therefore comprise a methodical distribution of plants according to their organization, with their characters arranged in proper subordination; so that the investigation of any one particular species will bring to view, not only its name (which separately considered is of little importance), but also its plan of structure, both in general and in particular, its relationships, essential qualities, and whole natural history. The classification and the method of investigation in natural history con- stitute not only the most complete arrangement known for the col- location of a vast amount of facts, but also the best system of prac- tical logic; and the study exercises and sharpens at once both the powers of reasoning and of observation, more, probably, than any other pursuit. As a system for collocating facts for convenient ref- erence, a great practical advantage of natural history is secured by its happily devised 710. Binomial Nomenclature: Since the time of Linnaeus, who in- troduced the system, the scientific name of every plant is expressed by two words, viz. by the name of its species appended to that of its genus, each of a single word. That of the genus, i. e. the ge- neric name, is a substantive; that of the species, or the specific name, is an adjective adjunct. The same name is never employed for different genera; the same specific name is not available for more than one species of the same genus, but may be used in any other genus. A few thousand names accordingly serve completely to designate something like 8,000 genera and nearly 100,000 species of plants, in a manner which obviates all confusion, and does not greatly burden the memory. The generic name of a plant answers to the surname of a person, as Brown or Jones ; the specific name answers to the baptismal name, as John or James. Thus, Quercus alba is the botanical appellation of the White Oak ; Quercus being the substantive name for the genus, and alba (white) the adjec- tive name for this particular species ; while the Red Oak is named Quercus rubra ; the Scarlet Oak, Quercus coccinea ; the Live Oak, Quercus virens; the Bur Oak, Quercus macroccirpa; and so on.364 PRINCIPLES OP CLASSIFICATION. The scientific names of plants are all Latin or Latinized ; and that of the species always follows that of the genus. 711. Generic names in botany are derived from various sources. Those of plants known to the ancients generally preserve their clas- sical appellations ; as, for example, Quercus, Fagus, Corylus, Prunus, Myrtus, Viola, &c. For plants since made known, even their barba- rous names are often adopted, when susceptible of a Latin termina- tion, and not too uncouth; for example, Thcea and Coffcea, for the Tea and Coffee plants, Bambusci for the Bamboo, Yucca, Negundo, &c. But more commonly, new generic names, when wanted, have been framed by botanists to express some botanical character, habit, or obvious peculiarity of the plants they designate ; such as Arena- ria, for a plant which grows in sandy places; Dentaria, for a plant with toothed roots; Lunaria, for one with moon-like pods; Sanguinaria, for the Bloodroot with its sanguine juice ; Crassida, for some plants with remarkably thick leaves. These are instances of Latin derivatives; but recourse is more commonly had to the Greek language, in which compounds of two words are much more readily made, expressive of jieculiarities ; such as Menispermum, or Moonseed ; Lithospermum, for a plant with stony seeds ; Melanthium, for a genus whose flowers turn black or dusky; Epidendrum, for certain Orchideous plants which grow upon trees; Liriodcndron, for a tree which bears lily-shaped flowers, &c. Genera are also dedicated to distinguished persons; a practice commenced by the ancients ; as Pceonia, which bears the name of Pieon, who is said to have employed the plant in medicine ; and Euphorbia, Artemisia, and Asclepias are also examples of the kind. Modern names of this kind are freely given in commemoration of botanists, or of persons who have contributed to the advancement of natural history. 1Mag- nolia, Bignonici, Lobelia, and Lonicera, dedicated to Magnol, Big- non, Lobel, and Lonicer, are early instances; JAnncea, Tourneforda, Jussicea, Hcdleria, and Gronovia, bear the names of the most cel- ebrated botanists of the eighteenth century; and at the present day almost every devotee of the science is thus commemorated. 712. Specific names are adjuncts, and mostly adjectives, adopted on similar principles. Most of them are expressive of some char- acteristic or obvious trait of the species ; as, Magnolia grandiflora, the Large-flowered Magnolia; M. macropliylla, the Large-leaved Magnolia; M. glauca, which has the foliage glaucous or whitened underneat) i ; or Viola tricolor, from the tliree-colored corolla of theNATURAL AND ARTIFICIAL SYSTEMS. 365 Pansy ; V. rostrata, a remarkably long-spurred species; V rotundi- folia, with rounded leaves ; V. lanceolata, with lanceolate leaves ; V.pedata, with pedately parted leaves ; V primulce/olia, where the leaves are compared to those of the Primrose; and V. pubescens, with pubescent or hairy herbage. Sometimes the specific name re- fers to the country which the plant inhabits or was first found in, as Viola Canadensis, the Canadian Violet; or to the station where it naturally grows, as V. palustris (Marsh Violet). Sometimes it com- memorates the discoverer or describer, when it rightly takes the genitive form, as Viola Muhlenbergii, V Nuttallii, &c. When com- memorative names are given merely in compliment to a botanist un- connected with the discovery or history of the plant, the adjective form is preferred; as, Carex Torreyana, C. Hookeriana, &c.: but this rule is not universally followed. Specific names are sometimes substantive; •as, Magnolia Umbrella, Ranunculus Flammula, Hypericum Sarothra, Linaria Cymbalaria, &e. (most of these being old generic names used as specific); when they do not necessarily accord with the genus in gender. These, as well as all specific names taken from persons or countries, are to be written with a capital initial letter. 713. Varieties may be designated by names when they are re- markable enough to require it. The name of the variety, when used at all, follows that of the species, and is formed on the same plan. Subgenera need to be designated by names, which are sub- stantive, and on the same principle as generic names. These are convenient to refer to, but are not a part of the proper name of a plant, which is that of the genus and species only. 714. The names of genera and species are the same in all botani- cal systems, and therefore are properly alluded to here. But those of orders, and all other groups higher than genera, vary in plan with the system adopted. Classifications are of two sorts, viz. 715. Natural and Artificial Systems. A natural system carries out in practice as perfectly as possible the principles sketched in this chapter, arranging all known species in groups of various grades in view of their whole plan of structure, so placing each genus, tribe, order, &c. next to those it most resembles in all respects. An arti- ficial system arranges the genera by some one character, or set of characters, chosen for convenience, disregarding other considerations.. It aims only to provide an easy mode of ascertaining the names of plants, and does not attempt to express their points of resemblance generally, but serves nearly the same purpose as a dictionary. 31*366 THE PKINCIPI.ES OF 716. Artificial systems are no longer used in botany, except as keys or helps in referring plants to their proper groups in natural arrangements. But the celebrated Artificial System of Linnseus so long prevailed, and has exerted so great an influence over the progress of the science, that it is still desirable for the student to understand it. It will therefore he explained, after we have illus- trated the principles of the Natural System of Botany. CHAPTER II. OF THE NATURAL SYSTEM OF BOTANY. 717. The object proposed by the Natural System of Botany is to bring together into groups those plants which most nearly resem- ble each other, not in a single and perhaps relatively unimportant point (as in an artificial classification), hut in all essential particu- lars ; and to combine the subordinate groups into successively more comprehensive natural assemblages, so as to embrace the whole ■vegetable kingdom in a methodical arrangement. All the charac- ters which plants present, that is, all their points of agreement or difference, are employed in the classification ; those which are com- mon to the greatest number of plants being used for the primary grand divisions ; those less comprehensive, for subordinate groups, &c.; so that the character, or description of each group, when fully given, actually expresses the main particulars in which the plants it embraces agree among themselves, and differ from other groups of the same rank. This complete analysis being carried through the system, from the primary divisions down to the species, it is evident that the study of a single plant of each group will give a correct general idea of the structure, habits, and even the sensible proper- ties, of the whole. 718. For it is evident that the relationships of plants are real; that there is not only a general plan of vegetation (with which the student has already become familiar), but also a plan in the relations which subsist between one plant and another; that the species sustain to each other the relation of parts to a whole, — so that this whole, or vegetable kingdom, is an organized system. And this system, asTHE NATURAL SYSTEM OF CLASSIFICATION. 367 far as comprehended, may be to a good degree expressed in. our classification. This idea of plan and system in nature supposes a Planner, or a mind which has ordered things so, with intelligence and purpose; and it is this plan, or its evidences and results, which the naturalist is endeavoring to investigate. The botanist, accordingly, does not undertake to contrive a system, but he strives to express in a classification, as well as he can, the System of Nature, or, in other words, the Plan of the Creator in the Vegetable Kingdom. 719. “ So there can be only one natural system of botany, if by the term we mean the plan according to which the vegetable crea- tion was called into being, with all its grades and diversities among the species, as well of past as of the present time. But there may be many natural systems, if we mean the attempts of men to inter- pret and express the plan of the vegetable creation, — systems which will vary with our advancing knowledge, and with the judg- ment and skill of different botanists, — and which must all be very imperfect. They will all bear the impress of individual minds, and be shaped by the current philosophy of the age. But the endeavor always is to make the classification a reflection of Nature, as far as any system can be which has to express such a vast and ever in- creasing array of facts, and most various and intricate relations, in a series of definite propositions, and have its divisions and subdi- visions following each other in some fixed order.’' Our so-called natural methods must always fail to give more than an imperfect and considerably distorted reflection, not merely of the plan of the vegetable kingdom, but even of our knowledge of it; and every form of it yet devised, or likely to be, is more or less artificial, in some of its parts or details. This is inevitable, because, — 720. (1st.) The relationships of any group cannot always be right- ly estimated before all its members are known, and their whole structure understood ; so that the views of botanists are liable to be modified with the discoveries of every year. The discovery of a single plant, or of a point of structure before misunderstood, has sometimes changed materially the position of a considerable group in the system, and minor alterations are continually made by our in- creasing knowledge. (2d.) The groups which we recognize, and dis- tinguish as genera, tribes, orders, &c., are not always, and perhaps not generally, completely circumscribed in nature, as we are obliged to assume them to be in our classification. This might be expected from the nature of the case. For the naturalist’s groups, of what-368 THE PRINCIPLES OP ever grade, are not realities, but ideas ; their consideration involves questions, not of things, between which absolute distinctions might be drawn, but of degrees of resemblance, which may be expected to present infinite gradations. (3d.) Although the grades of affinity among species are most various, if not wholly indefinite, the nat- uralist reduces them all to a few, and treats his genera, tribes, &c. as equal units, or as distinguished by characters of about equal value throughout, — which is far from being the case. (4th.) The nat- uralist in his works is obliged to arrange the groups he recognizes in a lineal series ; but each genus, or order, &c. is very often about equally related to three or four others ; so that only a part of the relationship of plants can practically be indicated in the published arrangement. 721. The natural system as sketched by Bernard and A. L. Jus- sieu, and improved by the labors of succeeding botanists, essentially consists of an arrangement of the known genera according to their af- finities under two hundred or more natural orders, and of these under a few great types or classes. What is now most wanted to complete the system is a truly natural arrangement of the orders under the great classes, like that of the genera under their respective orders. Until this is done, the series in which the orders follow one another in botanical works must not be regarded as a part of the system of nature. Different authors adopt different modes of arranging them; and all of them that a learner could use are avowedly more or less artificial. 722. Omitting all historical details and statements of more or less conflicting views, we will briefly sketch the outlines of the principal divisions of the vegetable kingdom, according to the natural system as we now practically receive it. In explaining the principles of classification, we proceeded from the individual to the class. In ex- amining the actual construction of the system of botany, it is simpler to regard the vegetable kingdom as a whole, and show how it is nat- urally divided and subdivided. This is the course a student must follow with an unknown plant before him, which he wishes to refer first to its class, then to its order, and finally to its genus and species. 723. The long and complex series, stretching from the highest organized vegetable down to the simplest and minutest of the Fungi and Algaj, is most naturally divided, as we have already seen, into two parts, forming a higher and a lower grade or series (98), viz.THE NATURAL SYSTEM OF CLASSIFICATION. 369 Series I. Ph^enogamous (or Phanerogamous) or Flower- ing Plants (114, 117), which produce flowers and seeds, the latter containing a ready-formed embryo. Series II. Cryptogamous or Flowerless Plants (113, 117, 651), whose organs of reproduction are not flowers, but some more or less analogous apparatus, and which are propagated by spores or specialized cells. 724. We have next to consider how these two series may be themselves divided, in view of the most general and important points of difference which the plants they comprise exhibit. Whenever Phaenogamous plants rise to arborescent forms, a difference in port and aspect at once arrests attention; that which distinguishes our common trees and shrubs from Palms and the like (Fig. 184). On examination, this is found to accompany a well-marked important difference in the structure of the stem or wood, and in its mode of growth. The former present the exogenous, the latter the endoge- nous structure or growth (200-203, 207, &c.). This difference is equally discernible, if not so striking, in the annual or herbaceous stems of these two sorts of Phaenogamous plants. A difference is also apparent in their foliage ; the former generally have reticulat- ed, or netted-veined, the latter •parallel-veined leaves (276). The leaves of the former usually fall off by an articulation; those of the latter decay on the stem (309, 310). The Phamogamous series, therefore, divides into two great classes, namely-, into Exogenous and Endogenous plants, more briefly named Exogens and Endo- Gens. The difference between the two not only pervades their whole port and aspect, but is manifest from the earliest stage, in the plan of the embryo. The embryo of Exogens, as already shown, is provided with a pair of cotyledons (or sometimes with more than one pair) ; that of Endogens, with only one; whence the former are also termed Dicotyledonous, and the latter Monocotyledo- nous plants (128, 641-643): names introduced by Jussieu, the father of this branch of botany.* Taking these divisions for classes, we have * There is, perhaps, no real and complete exception to the coincidence of an exogenous stem with a dicotyledonous (or polycotyledonous) embryo, and of an endogenous stem with a monocotyledonous embryo. Nyctaginaceous plants and some others have a few vascular bundles scattered through their pith, but the rest of the wood is regularly exogenous. The stalk of Podophyllum imi- tates an Endogen, but the subterranean rootstock is truly exogenous, as it should370 THE PRINCIPLES OF Class I. Exogenous or Dicotyledonous Plants ; those with endogenous stems, netted-veined leaves, and dicotyledonous (or rarely polycotyledonous) embryo; Class II. Endogenous or Monocotyledonous Plants ; those with endogenous stems, mostly parallel-veined leaves, and monocotyledonous embryo. 725. Without entering here into a particular explanation of the diversities of structure which Cryptogamous plants present, suffice ’ it to say that they exhibit three grades of simplification as to their vegetation, which appear to correspond with three different modes of fertilization. Plants of the highest grades of the Cryptogamous series have wood and ducts in their composition (i. e. they are vascu- lar plants, 111), and display the ordinary type of vegetation, viz. with an axis or stem, bearing distinct foliage. But this stem in structure is neither endogenous nor exogenous, and grows from the apex only, having no primary root; whence these vascular Flower- less plants have been called Acrogens, or Acrogenous plants. Of this kind are Ferns, Lycopodiace®, Equisetace® or Horsetails, &c. These plants, it appears, produce their organs analogous to flowers, and have their fecundation effected, once for all, upon the infantile or germinating plantlet, and the result is the origination of a bud, which develops into the adult plant; and that bears the fruit, in the form of spore-cases and spores (GG3). Here then are the characters of Class III. Acrogenous Plants ; Cryptogamous plants, with a distinct axis and mostly with foliage, having wood and ducts in their composition: fertilization occurring upon a transient germinat- ing plantlet, and giving rise to the adult plant. 726. The other Cryptogamous plants, being composed of paren- chyma only, (or with slight exceptions,) are called Cellular plants (111). Among them the Mosses and Liverworts present for the most part the ordinary plan of vegetation ; their organs analogous to flowers appear in the adult plant; and the fertilization of the pistillidium gives origin to a sporangium in which a multitude of spores, capable of germination, are developed. These compose Class IV. Anophytes : cellular Cryptogamous plants, with distinct stem and foliage, or sometimes these parts confluent into a be. The trunks or rootstocks of Water-Lilies appear to be endogenous; but those who have investigated them minutely, declare that they are not really so.THE NATURAL SYSTEM OF CLASSIFICATION. 371 frond, composed of parenchyma alone : fertilization giving rise to a sporangium filled with spores. 727. The remaining and lower grade consists of plants such as Lichens, Seaweeds or Alg®, and Fungi, which exhibit no clear dis- tinction into stem, root, and leaves, but consist of single cells or rows of cells in their lowest grades, and in the higher, of masses of cells disposed in almost every shape, but tending mostly to flat strata or expansions ; hence the vegetation is termed a thallus (or bed), and this word gives a name to the class, viz. Class V. Thallophytes : cellular Cryptogamous plants with no distinction of axis and foliage ; their spores mostly directly fer- tilized (as explained in another place, 656-661). 728. These five classes are unequal in extent and diversity; the Exogenous class containing much the largest number of orders ; the Endogens also comprising a considerable number; the others com- prise few orders or main types, but are most of them very rich in tribes, genera, and species. 729. Only the first or highest class presents such marked diver- sity of type among the plants it comprises as to call for the estab- lishment of subclasses, that is, of groups of such importance as to raise the question whether they should not be regarded as classes. This question is raised by the peculiarities of Conifer® (Pines, Cy- presses, the Yew, &c.), and by the tropical order of Cycadaee®; in which, not only are the flowers reduced to the greatest simplicity, but the fertile ones consist of naked ovules merely, borne on the margins or surface of a sort of open leaf, or else of an ovule, without anything answering to a pistil at all. But as these plants are truly exogenous and dicotyledonous (or often polycotyledonous), the better opinion is that they should be ranked under the Exogenous or Dicotyledonous class, as a subclass. So that, while the main body of the first class consists of Subclass I. Angiospermous Exogens : viz. those with proper pistils enclosing their ovules in an ovary, in the ordinary manner ; the pollen to fertilize the ovules received upon a stigma (420, 559, 574), — the others form the Subclass II. Gymnospermous Exogens: those with naked ovules and seeds (as the name denotes), which are fertilized by direct application of the pollen (560, 573, 625). 730. The general plan of the classes and subclasses may be pre- sented in one view, as in the subjoined synopsis.Synoptical View of the Classes in the Natural System. Ser. 1. PILENOGAMOUS PLANTS, with Exogenous growth and a dicotyledonous embryo. Class I. EXOGENS, or DICOTYLEDONS. Seeds in a pericarp. Subclass 1. Angiosperms. Seeds naked. 41 2. Gymnosperms. Endogenous growth and a monocotyledonous embryo. “ II. ENDOGENS, or MONOCOTYLEDONS. Ser. n. CRYPTOGAMOUS PLANTS, with- h ( woody and vascular tissue. Class III. ACROGENS.l a distinct axis, or stem and foliage, containing^ [ cellular tissue only. 1 IV. ANOPHYTES.' no distinction of stem and foliage, but all confounded in a thallus. Y. TIIALLOPHYTES. 372 the natural classes,ILLUSTRATIONS OF THE NATURAL ORDERS. 373 731. The arrangement and general character of the principal orders under each class form the’ subject of the ensuing chapter. Before entering upon it, the 732. Nomenclature of Orders, Tribes, &c. requires some explanation. The names of such groups are in the plural number. As a gen- eral rule, the name of an order is that of some leading or well-known genus in it, prolonged into the adjective termination acece. Thus, the plants of the order which comprises the Mallow (Malva) are called Malvaceae ; that is, Plantce Malvaceae, or, in English, Malva- ceous plants: those of which the Bose (Rosa) is the well-known representative are Rosacece, or Rosaceous plants, &c. Some few ordinal names, however, are differently formed, and directly indicate a characteristic feature of the group ; as, for instance, Leguminosa, or the Leguminous plants, such as the Pea, Bean, &c., whose fruit is a legume (610) ; Umbelliferce, or Umbelliferous plants, so named from having the flowers in umbels ; Composite, an order having what were termed compound flowers by the earlier botanists (394) ; Labiates, so called from the labiate or two-lipped corolla which nearly all the species' exhibit; Crucifer m, which have their four petals disposed somewhat in the form of a cross (Fig. 405). 733. Suborders, tribes, and all other groups between orders and genera, bear names framed upon the same principles, that is, they are plural, substantively-taken adjectives, derived from the name of some characteristic .genus of the group. Thus the genus Rosa gives name to a particular tribe, Rosea, of the order Rosacea ; the genus Malva to the tribe Malvece, of the order Malvacea, &c., — the termination in acece being avoided, because reserved for ordinal names. CHAPTER III. ILLUSTRATIONS OF THE NATURAL ORDERS OR FAMILIES. 734. Some authors (such as Jussieu and Endlicher) commence with the lower extremity of the series, and end with the higher; while others (as De Candolle) pursue the opposite course, beginning with the more perfect Flowering plants, and concluding with the 32374 ILLUSTRATIONS OF THE NATURAL ORDERS. lowest grade of Flowerless plants. The first mode possesses the theoretical advantage of ascending by successive steps from the simplest to the most complex structure ; the second, the great prac- tical advantage of beginning with the most complete and best under- stood, and proceeding gradually to the most reduced and least known forms, or, in other words, from the easiest to the most dif- ficult ; and is therefore the best plan for the student. 735. Until the orders shall have been successfully associated into natural alliances or superior groups, (of whatever name,) it is most convenient to follow De Candolle’s arrangement of them, in a gen- eral way, with such minor alterations as may be called for. The principal Floras now in use are arranged upon this general method. It commences with the Exogenous class, with those orders of it which are generally provided with complete flowers, and which ex- hibit the floral organs in the most normal condition, according to our theory of the blossom (Chap. IX., Sect. I. - HI.), that is, which have most of the several parts free and separate. It pro- ceeds to those which are characterized by the union or consolida- tion of their floral organs, and then to those which are reduced or simplified by the suppression or obliteration of parts, ending with the Gymnospermous subclass, the flowers of which are extremely simpli- fied. The Endogenous class succeeds, with a somewhat analogous arrangement, ending with Grasses ; and the classes of the Cryp- togamous series follow in the order of their rank. 736. The following cursory sketch takes in the principal orders, freely omitting, however, small and obscure ones, as well as certain well-characterized groups which have no interest to the ordinary student, and no indigenous, naturalized, or commonly cultivated rep- resentatives in the United States. Certain exotic orders are also omitted from the synopsis of the classes or large divisions, for greater simplicity, but arc briefly mentioned in their proper place. Fuller accounts of the natural orders, and of their systematic arrangement, structure, properties, &c., must be sought in more extensive works, such as Lindley’s Vegetable Kingdom, De Candolle’s Prodromus, &c. As applied to the botany of this country, what is essential is comprised in the Manual of the Botany of the Northern United States, by the present writer, and in similar Floras. The characters of the orders, &c. are drawn up in ordinary botanical language. For explanation of the technical terms used, the reader may consult the Glossary at the end of the volume.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 375 Series I. Flowering or Ph^enogamous Plants. Plants furnished with flowers (essentially consisting of stamens and pistils), and producing proper seeds. Class I. Exogenous or Dicotyledonous Plants. Stem consisting of a distinct bark and pith, which are separated by an interposed layer of woody fibre and vessels, forming wood in all perennial stems : increase in diameter effected by the annual deposition of new layers between the old wood and the bark, which are arranged in concentric zones and traversed by medullary rays. Leaves commonly articulated with the stems, their veins branching and reticulated. Sepals and petals, when present, more commonly in fives or fours, and very rarely in threes. Embryo with two (or rarely more) cotyledons. Subclass 1. Angiospermous Exogenous Plants. Ovules produced in a closed ovary, and fertilized by the action of pollen through the medium of a stigma. Embryo with a pair of op- posite cotyledons. (For convenience, the very numerous orders of this subclass are divided into those with polypetalous, monopetalous, and apetalous flowers. This holds in a general way ; but a good many genera and species of mainly polypetalous, and some of mono- petalous orders, are apetalous. The character of the following divis- ion must therefore be regarded as liable to exception in this respect. For example, many of the genera of the first order have apetalous flowers. — The earlier groups of this division are mostly hypogy- nous; those that succeed, perigynous ; the last are epigynous.) Division I. Polypetalous Exogenous Plants. Calyx and corolla both present; and the petals distinct. Conspectus of the Orders. Group I. Ovaries several or numerous (in a few cases solitary), distinct, when in several rows sometimes cohering in a mass, but not united into a com- pound pistil. Petals and stamens hypogynous. Seeds albuminous. * Stamens or pistils (one or both) numerous or indefinite. Herbs without stipules. Kanunculacea;. Shrubs or trees. Corolla imbricated in the bud. Magnoliaceas. Shrubs or trees. Corolla valvate in the bud. Anonace/e.376 ILLUSTRATIONS OF THE NATURAL ORDERS. * * Stamens few or definite, mostly before the petals. Pistils one or few. Climbing plants. Dioecious or monoecious. Menispermacea:. Not climbing. Flowers perfect. Anthers opening by valves. Berberidaceal Group 2. Ovaries several and distinct, or perfectly united into a compound, pistil of several cells. Embryo enclosed in a sac at the end of the albu- men, or, in Nelumbium, without albumen. Aquatic herbs. Carpels distinct, immersed in a dilated top-shaped torus. Nelumbiacea:. Carpels united into a several-cellcd and many-ovuled ovary. Nymphajaceaj. Carpels distinct and free. Stamens 6-18. Cabombaceaj. Group 3. Ovary compound, 5-celled, with the placentas in the axis. Sta- mens hypogynous, indefinite. Seeds numerous, anatropous, albuminous, with a small embryo. Marsh herbs, with singular pitcher-shaped or tubular leaves. Sarraceniacea:. Group 4. Ovary compound, with parietal placentae. Petals and sepals 2 or 4, deciduous. Stamens hypogynous. Flower unsymmetrical. Embryo small, in copious albumen, or coiled when there is no albumen. Seeds albuminous : embryo small or minute. Polyandrous : flower regular. Juice milky or colored. Diadelphous or hexandrous : flower irregular. Seeds without albumen : styles and stigmas united into one. Pod two-celled. Radicle folded on the cotyledons. Pod one-celled. Embryo rolled up. Seeds without albumen : styles or stigmas several. Papaveracea. Fumariacea:. Crucifer.*:. Capparidacea:. Resedacea:. Group 5. Ovary compound, with parietal placentae. Floral envelopes mostly 5-merous; calyx persistent. Stamens hypogynous. Seeds albuminous. Anthers (5) adnate, introrse, connate. Corolla irregular. Violacea:. Anthers extrorse, or innate, distinct. Corolla regular. Vernation circinate. Petals marcescent. Droseracea:. Vernation straight. Petals usually caducous. Cistaceas. Group 6. Ovary compound, with the placentae parietal, or 2-5-celled from their meeting in the axis. Stamens hypogynous. Seeds with a, straight embryo and little or no albumen. Sterile filaments or a lobed appendage before each petal. Parnassiacea:. Sterile filaments none : leaves opposite. Stipules none : leaves dotted. Stamens unsymmetrical. Hypericacea. Stipules present: leaves dotless. Stamens symmetrical. Elatinacea:. Group 7. Ovary compound, one-celled with * free central placenta, or 2- several-cclled with the placenta in the axis. Calyx free or nearly so. Stamens hyjmgynous or perigynous. Embryo peripheric, coiled more or less around the outside of mealy albumen. Petals and stamens numerous. Ovary many-celled. Mesembryanthemacea:. Petals 3 - 5 or 6, sometimes wanting. Floral envelopes symmetrical. Stamens 10 or fewer. Caryophyllacea:. Floral envelopes unsymmetrical, or stamens many. Portulacacea:.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 377 Group 8. Ovary compound and several-cclled, with the placentas in the axis; or the numerous carpels more or less coherent with each other or with a central axis. Calyx free from the ovary, with a valvate aestivation. Sta- mens mostly indefinite, monadelphous, or polyadelphous, inserted with the petals into the receptacle or base of the petals. Anthers 1-celled, reniform. Stamens monadelphous. Malvaceae. Anthers 2-cellcd. Fertile stamens few, monadelphous. Byttneriaceae. Anthers 2-cclled. Stamens polyandrous or polyadelphous. T iliac eve. Group 9. Ovary compound, with two or more cells, and the placentie in the axis, free from the calyx, which is imbricated in aestivation. Stamens in- definite, or twice as many as the petals, usually monadelphous, hypogy- nous. — Trees or shrubs. Leaves simple, not dotted. Stamens indefinite. Camei.liacf.e. Leaves pellucid-punctate, mostly compound. Aurantiaceve. Leaves compound, dotless. Stamens 10 or less, monadelphous. Seeds single in each cell, wingless. Meliaceas. Seeds several in each cell, winged. Cedrelaceve. Group 10. Ovary compound, or of several carpels adhering to a central axis, (or rarely distinct in the last two), free from the calyx, which is mostly im- bricated in aestivation. Stamens as many or twice as many as the petals, inserted on the receptacle, often monadelphous at the base. Embryo large. Albumen little or none. Flowers perfect, except in some Rutaccte. * Flower irregular and unsymmetrical. Albumen none. Stamens united over the pistil. Ovules several in each cell. Balsaminaceas. Stamens distinct. Ovules single in each cell. TROPAiOLACR®. * * Flower regular and mostly symmetrical. Leaves not punctate with transparent dots. Calyx valvate. Albumen none : cotyledons very thick. Calyx imbricated in aestivation. Embryo conduplicate : the radicle bent down on the convolute cotyledons. Embryo straight or nearly so. Stamens (fertile) 5. Leaves simple, entire. Stamens 10. Leaves opposite, compound. Stamens 10. Leaves alternate, mostly compound. Ovules more than one in each cell. Ovules only one in each cell. Leaves punctate with transparent dots. Limnantiiacea;. GERANIACEVE. Linaceve. ZyGOPII YLLACILE. OXALIDACE.E. SlMARtJBACEAi. Rutaceae. Group 11. Ovary one, or several and distinct or combined into one, with one or rarely two ovules in each cell. Calyx free; stamens more or less perigynous, as many or twice as many as the petals. Embryo large : albumen none. Shrubs or trees with a resinous or viscid-milky juice, and mostly polygamous or dioecious flowers. Leaves not punctate. —- In tem- perate climates represented only by Axacakdi ack.e. 32*378 ILLUSTRATIONS QF TIIE NATURAL ORDERS. Group 12. Ovary compound, 1 - 5-celled, with one or two ovules erect from the base of the cells. Calyx free or partly adherent. Stamens as many as the petals or sepals and opposite the former. Seeds anatropous, albumi- nous. Woody plants, with a colorless juice. Flowers regular. Leaves alternate. Calyx obscure. Petals valvate, caducous. Embryo minute. "Vitaceas. Calyx more conspicuous than the petals, valvate. Rhamnaceac. Group 13. Ovary compound, 2-5-cellcd, with only one or two ovules in each cell. Stamens as many as the petals and alternate with them, perigynous. Seeds furnished with an arillus, albuminous, with a large straight embryo. Woody plants, with regular flowers and simple leaves. — Represented mainly by Celastraceje. Group 14. Ovary compound and 2 -3-celled, with one or two (rarely 3 or 4) ovules in each cell, free from the calyx, which is imbricated in aestivation. Flowers often irregular, and sometimes unsymmetrical. Stamens definite, hypogynous or perigynous. Shrubs, trees, or herbs. Leaves opposite or alternate, not punctate. Stamens distinct, inserted on a hypogynous or perigynous disk. Embryo (except in Staphylea) variously curved or coiled, and destitute of albumen. Sapindaceas. Stamens hypogynous, without a disk. Stamens mostly monadelphous, 10. Flowers regular. Embryo curved; albumen none. Malpighi ace a:. Stamens monadelphous or diadelphous, 6 or 8. Flower irregu- lar and unsymmetrical. Embryo straight in albumen. Polygalaceas. Group 15. Ovary simple and solitary, free from the calyx; the fruit a pod. Flower 5-merous, the odd sepal anterior. Corolla papilionaceous, irregu- lar, or sometimes regular. Stamens monadelphous, diadelphous, or dis- tinct, mostly perigynous. Seeds destitute of albumen Stamens hypogynous, the anterior wanting. Stipules none. Krameriaceas. Stamens mostly perigynous. Fruit a legume. Leguminosa:. Group 16. Ovaries one or several, cither simple' and distinct, or combined into a compound ovary with two or more cells and the placentae in the axis. Petals and the distinct stamens perigynous. Seeds destitute of albumen. * Calyx free, although often enclosing the ovaries in its tube, except when the latter are united, when it is adnatc to the compound ovary, and the sta- mens are indefinite. Leaves alternate, stipulate. Cotyledons plane. Rosacea:. Leaves opposite, not stipulate, nor pellucid-punctate. Calycanthaceaj. Leaves opposite, not stipulate, pellucid-punctate. Myrtacea:. * * Calyx free from the compound ovary. Stamens definite. Lythraceai.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 379 * * * Calyx-tube adnate to the compound ovary. Stamens definite. Melastomaceae. Rhizophoraceas. COMBRETACEAS. Onagracea:. Anthers opening by a pore at the apex. Anthers opening longitudinally. Stipules between the petioles. Leaves opposite. Stipules none. Calyx valvate. Cotyledons convolute. Fruit indehiscent, l'-celled. Cotyledons plane. Fruit mostly 2 -4-celled. Group 17. Ovary compound, one-celled, with parietal placentas. Petals and (with one exception) stamens inserted on the throat of the calyx. Flowers perfect, except in Papayaceae. * Calyx adherent to the ovary. Albumen none or very little. Petals and stamens indefinite. Cactace.-e. Albumen very copious. Embryo minute. Stamens 5. Grossolaceje. Albumen present. Embryo rather large. Stamens indefinite. Loasacea:. * * Calyx free from the ovary. Flowers perfect. Stamens 5. Stamens distinct and perigynous. Stamens monadelphous, adnate to the gynophore. Flowers dioecious. Stamens 10, on the corolla. Turneraceas. Passiflorace-e. Papayaceas. Group 18. Ovary compound, one - several-celled, the placentae parietal (either truly or falsely so). Calyx adnate. Corolla frequently monopctalous. Stamens mostly united either by their filaments or anthers. Flowers dioecious or monoecious. Albumen none. Succulent or tender vines with tendrils. Cucurbitace-e. Group 19. Ovaries two or more, many-ovuled, distinct, or partly, sometimes completely, united, when the compound ovary is one-celled with parietal placentte, or 2-many-celled with the placentae in the axis. Calyx either free from the ovary or more or less adherent to it. Petals and stamens inserted on the calyx; the latter mostly definite. Seeds albuminous, nu- merous. Pistils of the same number as the sepals. Pistils fewer than the sepals, more or less united. Crassulaceas. Saxifragace-e. Group 20. Ovary compound, 2- (rarely 3-5-) celled, with » single ovule sus- pended from the apex of each cell. Stamens usually as many as the pet- als or the lobes of the adherent calyx. Embryo small, in hard albumen. * Summit of the (often 2-lobed) ovary free from the calyx; the petals and sta- mens inserted on the throat of the calyx. Hamamelace-e. * * Calyx-tube entirely adherent to the ovary. Stamens and petals cpigynous. Fruit separable into two dry carpels. Flowers umbellate. Umbebliferas. Fruit drupaceous, usually of more than two carpels. Araliaceae. Fruit a 1 - 2-celled drupe. Flowers cymose or capitate. Coexacete.380 ILLUSTRATIONS OF THE NATURAL ORDERS. 737. Ord. Ranunculaces (Crowfoot Family). Herbaceous, occa- sionally climbing plants, with an acrid watery juice, and usually palmately or ternately lobed or divided leaves, without stipules. Calyx of three to six, usually five, distinct sepals, deciduous, except in Pmonia and Ilelleborus. Petals five to fifteen, or often none. Stamens indefi- nite, distinct. Ovaries nu- merous, rarely few or soli- tary, distinct, in fruit becoming achenia (Fig. 566, 567) or follicles (Fig. 579, 648, 649), or in Actaja a berry. Embryo minute, at the base of firm albumen (Fig. 650, 610). — Ex. Ranunculus, the But- tercup (Fig. 645), which has regular flowers with petals. Clematis (Vir- gin’s Bower, which is the type of a tribe), Anemone (Fig. 411), Hepatica (Liver-leaf), &c. have no petals, but the calyx is petaloid. In these the flow- ers are regular. The Larkspur (Fig. 398) and Monkshood (Fig. 401) have the flowers irregular, and the Colum- bine (Fig. 646) has petals in the form of spurs. Actrea (Banebcrry) and one Larkspur have a solitary ovary: in the latter the petals are consoli- dated. Zanthorhiza (Yellow-root) has only five or ten stamens. — The juice of all Ranunculaceous plants is acrid, or even caustic: some, as the Aconite, are virulent narcotico-acrid poisons. 738. Ord. Dilleiliaccffi, consisting chiefly of tropical and Australian shrubs and trees, probably includes Crossosoma of Nuttall, a singu- lar Californian genus. The order ranks between the preceding and succeeding, but is nearer the former, from which it is known by its arillate seeds. FIG. 645. Vertical section of the flower of a Buttercup. FIG. 646. Flower and part of a leaf of Aquilegia Canadensis (Wild Columbine). 647. A detached petal. 648. The five carpels of the fruit. 649. A separate follicle. 650. Vertical section of the seed, showing the minute embryo. 616EXOGENOUS OR DICOTYLEDONOUS PLANTS. 381 739. Ol*d. MagnoliacefE (Magnolia Family). Trees or shrubs; with ample and coriaceous, alternate, entire or lobed leaves, usually punctate with minute transparent dots: stipules membranaceous, en- veloping the bud, falling off when the leaves expand. Flowers soli- tary, large and showy. Calyx of three deciduous sepals, colored like the petals; the latter in two or more series of three. Stamens nu- merous, with adnate anthers. Carpels either several in a single row, or numerous and spicate on the prolonged receptacle; in the latter case usually more or less cohering with each other, and form- ing a fruit like a cone or strobile. Seeds mostly one or two in each carpel, sometimes drupaceous and suspended, when the carpels open, by an extensile thread, composed of unrolled spiral vessels. Em- bryo minute, at the base of homogeneous fleshy albumen. There are three well-marked suborders, by many ranked as orders, viz.: — 740. Snhord. Magnolierc (Magnolia Family proper), characterized principally as above, especially by the stipules and the imbricated spiked carpels: — represented by Magnolia and Liriodendron. The bark, &c. is bitter and aromatic, with some acridity. 741. Subot'd. WjIItcrt’tc (Winter's-Bark Family) has no stipules, and the carpels occupy only a single verticil. These have more FIG. 651. Magnolia glauca. 652. A stamen, seen from the inside, showing the two lobes of the adnate anther. 653. The carpels in fruit, persistent on the receptacle, and opening by the dorsal suture ; the seeds suspended by their extensile cord of spiral vessels. 651382 ILLUSTRATIONS OF THE NATURAL ORDERS. pungent and purer aromatic properties ; as in Illicium, the Star-Anise, the seeds and pods of which furnish the aromatic oil of this name. 742. Sllbortl. Scllizandl'CEE is monmcious or dioecious, with the pis- tils spicate or capitate on a prolonged receptacle; the stamens often monadelplious. Leaves sometimes toothed, destitute of stipules.— Ex. Schizandra. These are mucilaginous, with little aroma. 743. Ol'd. Moilimiacere is a small group, found in the southern hemisphere, with pungent aromatic properties, most allied to the last order according to Dr. Hooker (or to Calycanthacece, according to Tulasne), but chiefly apetalous, and with opposite leaves. 744. Ol'd. AnonacefE {Custard-Apple Family). Trees or shrubs, with alternate entire leaves, destitute of stipules. Flowers large, but dull-colored. Sepals 3. Petals 6, in two rows, valvate in lesti- 657 656 vation. Stamens numerous, in many rows, with extrorse anthers. Carpels few, or mostly numerous and closely packed together, some- times cohering and forming a fleshy or pulpy mass in the mature FIG. 654. Flowering branch of the Papaw (Asimina triloba) of the natural size. 655 The receptacle, with all but the pistils removed. 656. A stamen, magnified. 657. View of three baccate pods from the same receptacle (much reduced in size); one cut across, another length- wise, to show the large bony seeds. 658. Section of the seed, to show the ruminated albumen.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 383 fruitT Seeds one or more in each carpel, with a hard and brittle testa: embryo minute, at the base of hard, ruminated albumen. The four species of our so-called Papaw (Asimina) are our only rep- resentatives of this chiefly tropical order, which furnishes the lus- cious custard-apples of the East and West Indies, &c. Aromatic properties, with some acridity in the bark, &c., prevail in the order. Monodora yields the calabash-nutmeg. 743. Ofd. Myristicacee® {Nutmeg Family), consisting of a few tropi- cal trees (which bear nutmegs), differs from Anonaceae in having monoecious or dioecious and apetalous flowers, &c. The aril and the albumen of the seeds are fine aromatics. The common nutmeg is the seed of Myristica moschata (a native of the Moluccas) deprived of the testa: mace is the aril of the same species. The ruminated albumen is nearly peculiar to this family and the Anonaceae. 746. Ord. Menispcrmaccsc {Moonseed Family). Climbing or twin- ing shrubby plants, with alternate and simple palmately-veined leaves, destitute of stipules ; and small flowers in racemes or panicles, mostly dioecious, the parts commonly in two or more rows of three or four each. Calyx of three to twelve sepals, in one to three rows, deciduous. Petals as many as the sepals or fewer, small, or some- times wanting in the pistillate flowers. Stamens as many as the petals, and opposite them, or two to four times as many: anthers 660 659 661 666 often four-celled. Carpels usually several, but only one or two of them commonly fructify, at first straight, but during their growth FIG. 659. Staminate flower of Menispermum Canadense. 660. A stamen, with its four- lobetl anther. 661. A pistillate flower of the same. 662. A solitary fruit. 663. Two drupes- on the same receptacle, cut across ; one.through the pulpy exocarp only, the other through the bony endocarp and seed. 664. A drupe divided vertically (the embryo here is turned the wrong way). 665. The seed, and, 666, the coiled embryo detached.384 ILLUSTRATIONS OF THE NATURAL ORDERS. often curved into a ring; in fruit becoming berries or drupes. Seeds solitary, tilling the cavity of the bony endocarp: embryo large, curved or coiled in the thin fleshy albumen. — Mehispermum, or Moonseed (Fig. 413, 414, 059 - GOG), Cocculus. The roots are bitter and tonic (e. g. Colombo Root of the materia medica) ; but the fruit is often narcotic and acrid ; as, for instance, the very poisonous Cocculus Indie us of the shops, once used for rendering malt liquors more intoxicating, and for stupefying fishes. 747. Old. Bci'bcridacetc {Barberry Family). Herbs or shrubs, with a watery juice ; the leaves alternate, compound or divided, usu- ally without stipules. Flowers perfect. Calyx of three to nine sepals, imbricated in one to several rows, often colored. Petals as many as the sepals and in two sets, or twice as many, often with a pore, spur, or glandular appendage at the base. Stamens equal in FIG 668. A shoot of Berberis vulgaris, the common Barberry. 669. A flowering branch from the axil of oue of its leaves or spines, the following year. 670 An expanded flower. 671 A petal, nectariferous Dear the base. 672. A stamen ; the anther opening by uplifted valves. 673- Cross-section of a young fruit. 674 Vertical section; the seeds attached at the base. 675. Vertical section of a seed enlarged, showing the large embryo with foliaceous cotyledons and a taper radicle, surrounded by albumen. 676. The embryo separate.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 385 number to the petals and opposite them, or rarely more numerous; anthers extrorse, the cells commonly opening by an uplifted valve (Fig. 475, 672). Carpel solitary, often gibbous or oblique, forming a one-celled pod or berry in fruit. Seeds sometimes with an aril: embryo (often minute) surrounded with a fleshy or horny albumen. — Ex. The Barberry, the sharp spines of which are transformed leaves ; the Mahonias are Barberries with pinnated leaves. Caulo- phyllum thalietroides, the Blue Cohosh, is remarkable for its eva- nescent pericarp (559), and the consequent naked seeds, which resemble drupes Podophyllum peltatum (the Mandrake) presents an exception to the ordinal character, having somewhat numerous stamens, with anthers which do not open by valves; but the latter anomaly is also found in Nandina. The order is remarkable for this valvular dehiscence of the anthers, and for the situation of both the stamens and petals opposite the sepals. But this latter pecu- liarity is easily explained away (461). The fruit is innocent or eatable; the roots, and also the herbage, sometimes drastic or poison- ous, as in Podophyllum. 748. Ol'd. NcIumMacCcE {Nelumbo Family). Aquatic herbs, with large leaves and flowers, on long stalks arising from a prostrate trunk or rliizoma, which has a somewhat milky juice: the leaves orbicular and centrally peltate. Calyx of four or five sepals, decid- uous. Petals numerous, inserted in several rows into the base of a large and fleshy obconical torus, deciduous. Stamens inserted into the torus in several rows: the filaments petaloid; the anthers ad- nate and introrse. Carpels several, separately immersed in hollows of the enlarged flat-topped torus or receptacle (Fig. 427), each con- taining a single anatropous ovule; in fruit forming hard, round nuts. Seed without albumen : embryo very large, with two fleshy cotyle- dons, and a highly developed plumule. — Ex. The order consists of the single genus Nelumbium, embracing two species ; one a native of Asia, the other of North America. They are chiefly remarkable for their large and showy leaves and flowers. The nuts are eatable. It should be regarded rather as a suborder of the next. 749. Ol'd. Nymphceaceaf {Water-Lily Family). Aquatic herbs, with showy flowers and cordate or peltate leaves, arising from a prostrate trunk or rliizoma, and raised on long stalks above the water, or floating on its surface. Calyx and corolla of several or numerous imbricated sepals and petals, which gradually pass into each other ; persistent; the latter inserted on the fleshy torus which surrounds 33386 ILLUSTRATIONS OF THE NATURAL ORDERS. or partly encloses and adheres to the pistil; the inner series gradu- ally changing into stamens. Stamens numerous, in several rows, inserted into the torus with or above the petals ; many of the outer filaments petaloid (Fig. 344), the adnate anthers introrse. Fruit in- dehiscent, pulpy when ripe, many-celled, crowned with the radiate stigmas; the anatropous seeds covering the spongy dissepiments. Embryo small, enclosed in a membranous bag, which is next the hilum, and half immersed in the mealy albumen. Structure of the trunk appearing rather endogenous than exogenous. — Ex. Nym- phcea, the White Water-Lily; Nuphar, the Yellow Pond-Lily; and 677 the magnificent Victoria of tropical South America, the most gigan- tic and showy of aquatics, both as to its flowers and its leaves. Mu- cilaginous plants, with slight astringency; no important properties. 750. Ord. Cabomltacc® (Water-shield Family) is really merely a simplified state of the last, with only one series of sepals and petals, FIG. 677. Open flower, with a flower-bud and leaf of the White Water-Lily (Nymphma odorata); the inner petals passing into stamens. 678. A flower with all the parts around the pistil cut away except one of the petaloid stamens, one intermediate, and one proper stamen. 679. An inner petal, with the imperfect rudiments of an anther at the tip. 680. Transverse section of an ovary.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 387 definite stamens, or nearly so, with innate anthers, and the gynoceium of few apocarpous, free, and few-ovuled pistils ; the ovules chiefly on the dorsal suture. Brasenia and Cabomba are all the genera. 751. Ord. Sarraceniacca' ( Water-Pitcher Family). Perennial herbs, growing in bogs; the (purplish or yellowish-green) leaves all radical and hollow, pitcher-shaped (Fig. 299, 300), or trumpet-shaped. Calyx of five persistent sepals, with three small bracts at its base. Corolla of five petals. Stamens numerous. Summit of the com- bined styles very large and -petaloid, five-angled, covering the five- celled ovary, persistent. Fruit five-celled, five-valved, with a large placenta projecting from the axis into the cells. Seeds numerous, albuminous, with a small embryo. — Sarracenia, from which the above character is taken, was the only known genus of the order, until the recent discovery of Heliamphora in Guiana, which is apeta- lous, its scape bearing several flowers ; as does that of a third genus, FIG. 681. Brasenia peltata (Water-shield); the lower flower with the floral envelopes and a part of the stamens removed. 682. A magnified stamen. 683. A magnified carpel. 684. The same, divided lengthwise, showing the ovules attached to the outer or dorsal suture! 685. Sec- tion of a carpel, in fruit. 686. A magnified seed, with half the outer integument removed, displaying at the upper extremity the bag which contains the embryo. 687. A magnified sec- tion through the middle of the albumen, &c.; bringing to view the minute embryo enclosed in its sac, lying outside of the albumen, which forms the principal bulk of the seed.388 ILLUSTRATIONS OF THE NATURAL ORDERS. Darlingtonia, Torr., recently discovered in California, with calyx and corolla not very unlike those of Sarracenia, but without the umbrella- like style. The species of Sarracenia are all Eastern North Amer- ican. The affinities of the group are unsettled. 752. Ol'd. PapaveracetE (Poppy Family). Herbs with a milky or colored juice, and alternate leaves without stipules. Calyx of two (rarely three) caducous sepals. Corolla of four to six regular petals. Stamens eight to twenty-four, or numerous. Fruit one-celled, with two to five or numerous parietal placentae, from which the valves often separate in dehiscence. Seeds numerous, with a minute em- bryo, and copious fleshy and oily albumen. — Ex. The Poppy (Pa- paver), the leading representative of this small but important family, is remarkable for the extension of the placentx so as almost to divide the cavity of the ovary into several cells, and for the dehiscence of the capsule by mere chinks or pores under the edge of the crown FIG. 688. Sanguinaria Canadensis (the Bloodroot). 689 The pod, divided transversely, showing the parietal attachment of the seeds 690 Longitudinal section of a magnified seed with its large rhaphe, showing the minute embryo, near the extremity of the albumen. 691. Flower-bud of Eschscholtzia. 692. The calyptriform calyx detached from the base. 693. Pod of the same.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 389 formed by the radiate stigmas. Eschsclioltzia, now common in gardens, is remarkable for the expanded apex of the peduncle, and for the union of the two sepals into a calyptra, like a candle-extin- guisher, which, separating at the base, is thrown off by the expan- sion of the petals. The colored juice is narcotic and stimulant. That of the Poppy yields Opium. That of the Celandine and of the Bloodroot (Sanguinaria) is acrid. 752'. Ortl. Ftumtriacea! (Fumitory Family). Smooth herbs, with brittle stems, and a watery juice, alternate dissected leaves, and no stipules. Flowers irregular. Calyx of two sepals. Corolla of four petals, in pairs ; the two outer, or one of them, spurred or sac-like at the base; the two inner, callous and cohering at the apex, includ- ing the anthers and stigma. Stamens six, in two parcels opposite the outer petals ; the filaments of each set usually more or less united ; the middle one bearing a two-celled anther; the lateral, with one-celled anthers. Fruit a one-eelled and two-valved pod, or round and indehiscent. Seeds with fleshy albumen and a small embryo. — Ex. Fumaria, Dicentra (Fig. 369-374), Corydalis. A small and unimportant tribe of plants, chiefly re- markable for their singular irregular flowers; by which, with their watery juice, they are distin- guished, and that not very definitely, from the pre- ceding family. 753. Ofll. Crucifer® (Mustard Family). Herbs, with a pungent or acrid watery juice, and alternate leaves without stipules ; the flowers in racemes or corymbs, with no bracts to the pedicels. Calyx of four sepals, deciduous. Corolla of four regular petals, with'claws, their spreading limbs forming a cross (Fig. 694). Stamens six, two of them short- er (tetradynamous, Fig. 695, 589). Fruit a pod (called a silique when much longer than broad, or a silicle when short, Fig. 703), which is two-celled by a membranous partition that unites the two marginal placentas, from which the two valves usually fall away. Seeds with no albumen : embryo with the cotyledons folded on the radicle. — Ex. The Water-Cress, Radish, Mustard, Cabbage, &c. A very natural order, perfectly distinguished by having six tetra- dynamous stamens along with four petals and four sepals, and by the FIG. 694. Flower of Mustard. 695. The stamens and pistil. 33*390 ILLUSTRATIONS OF TIIE NATURAL ORDERS. peculiar pod. The peculiarity of the stamens is explained, and the singular symmetry of the flower illustrated, on p. 243. All these jilants have a peculiar volatile acridity (and often an etlie- rdal oil, which abounds in sulphur) dispersed through every part, from which they derive their peculiar odor and sharp taste, and their stimulant, rubefacient, and antiscorbutic properties. The roots of some perennial species, such as the Horseradish, or the seeds of annual species, as the Mustard, are used as condiments. In some cultivated plants, the acrid principle is dispersed among abundance of saccharine and mucilaginous matter, affording wholesome food; as the root of the Turnip and Radish, and the leaves and stalks 638 699 697 701 of the Cabbage and Cauliflower. None are really poisonous plants, although ; ome are very' acrid. Several species are in FIG. 696 A Cruciferous flower. GOT. The same, with the calyx and corolla removed, show- ing the tetradynamous stamens. 698. Siliques of Arabis Canadensis; one of them with one of the valves detached, showing the seeds lying on the false partition; the other valve also falling away. 699. A magnified cross-section of one of the winged seeds, showing the embryo with the radicle applied to the edge of the cotyledons (cotyledons decumbent). 700 The embryo detached. 701. The raceme of Draba verna, in fruit. 702. A cross-section of one of the sili- cles, magnified, exhibiting the parietal insertion of the seeds, and the false partition 703. A silicic of Shepherd’s Purse (Capsella Bursa Pastoris). 704 The same, with one of the boat- shaped valves removed, presenting a longitudinal view of the narrow partition, &c. 705. A magnified cross-section of one of the seeds, showing the embryo with the radicle applied to the sido of the cotyledon (cotyledons incumbent).EXOGENOUS OK DICOTYLEDONOUS PLANTS. 391 cultivation, for their beauty or fragrance ; such as the Wall-flower, Stock, &c. 754. Orel. Capparitlacctc ( Caper Family). Herbs, or in the tropics often shrubs or trees; differing from Crucifer® in the onc-celled pod (which is often stalked) being destitute of any false partition ; in the kidney-shaped seeds; and in the stamens, which, when six, are scarcely tetradynamous, and are often more numerous. — Ex. Cle- ome, Polanisia, Gynandropsis; chiefly tropical or subtropical. Many have the pungency of Crucifer®, but are more acrid. Capers are the pickled flower-buds of Capparis spinosa of the Levant, &c. The roots and herbage or bark are bitter, nauseous, and sometimes poisonous. 755. Orel. Resedace® (Mignonette Family). Herbs, with a watery juice, and alternate leaves without stipules, except a pair of glands be so considered: the flowers in terminal racemes, small, and often fragrant. — Calyx persistent, of four to seven sepals, somewhat united at the base. Corolla of two to seven usually unequal and lacerated petals, with broad or thickened claws (Fig. 377). A fleshy disk is commonly present, enlarged posteriorly between the petals and the stamens, and bearing the latter, which vary from three to forty in number, and are not covered by the petals and sepals in the bud. Fruit a one-eelled pod, with three to six parietal placent®, three to six-lobed at the apex, where it opens along the FIG. 706. Flower of Gynandropsis. 707. Flower of Polanisia graveolens. 708. Fructified ovary of the same, a portion cut away by a vertical and horizontal section, to show the single cell and two parietal placentae. 709. Cross-section of the ovary. 710. Section of the seed and embryo.392 ILLUSTRATIONS OF TIIE NATURAL ORDERS. inner sutures, usually long before the seeds are ripe. Seeds several or many, curved or kidney-shaped, with no albumen ; the embryo incurved. — Ex. The common representatives of this order are the Mignonette (Reseda odorata), prized for its fragrant flowers, and the Weld (R. Luteola), which yields a poor dye. 75G. Ol'd. Flacourtiacc®, a group of tropical shrubs and trees, placed in this vicinity, is best known by Bixa Orellana, which yields Arnatto, the orange-red dried pulp of the pod, surrounding the seeds. 757. Oi'd. Violaceac {Violet Family). Herbs (in tropical countries sometimes shrubby plants), with mostly alternate simjile leaves, on petioles, furnished with stipules; and irregular flowers (Fig. 396, 397). Calyx of five persistent sepals, often auricled at the base. Corolla of five unequal petals, one of them larger than the others and commonly bearing a spur or a sac at the base: aestivation imbri- cative. Stamens five, with short and broad filaments, which are usually elongated beyond the (adnate introrse) anthers; two of them commonly bearing a gland or a slender appendage which is concealed in the spur of the corolla: the anthers approaching each other, or united in a ring or tube. Style usually turned to one side FIG. 711. Yiola sagittata. 712. One of the stamens without appendage, seen from within; and one furnished with a spur-like appendage on the back. 712a. A capsule which has opened and separated into three valves; the calyx still persistent. 712'. A vertical section of the seed and embryo.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 393 and thickened at the apex. Fruit a onc-ccllcd capsule, opening by three valves, each bearing a parietal placenta on its middle. Seeds several or numerous, anatropous, with a crustaceous integument, and a straight embryo, nearly the length of the fleshy albumen (Fig. 604, 605). — Ex. The Violet is the principal genus of this order; some species, like the Pansy, are cultivated for the beauty of their flow- ers ; others, for their delicate fragrance. The roots of all are acrid, and emetic. Those of some South American species of Ionidium furnish a part of the Ipecacuanha of commerce. 758. Ol'll. CistacefE (Rock-Rose Family). Low shrubby plants or herbs, with simple and entire leaves (at least the lower opposite). Calyx of five persistent sepals; the three inner with a convolute aestivation ; the two outer small or sometimes wanting. Corolla of five, or rarely three, regular petals, convolute in aestivation in the direction contrary to that of the sepals, often crumpled, usually ephemeral, sometimes wanting, at least a portion of the flowers. Stamens few or numerous, distinct, with short innate anthers. Fruit 719 718 a one-celled capsule with parietal placenta', or imperfectly three to five-celled by dissepiments arising from the middle of the valves (dehiscence therefore loculicidal), and bearing the placentae at or near the axis. Seeds few or numerous, mostly orthotropous, with mealy FlG. 713. The Rock-Rose, ECelianthemum Canadense. 714. Flower from which the petals and stamens have fallen. -715 Magnified cross-section of the ovary ; with a single stamen, showing its hypogynous insertion. 716 Cross-section of a capsule, loculicidally dehiscent; the seeds therefore borne on the middle of each valve. 717. An ovule. 718 Plan of the flower. 719. Section of a seed, showing the curved embryo.394 ILLUSTRATIONS OF THE NATURAL ORDERS. albumen. Embryo curved, or variously coiled or bent. —• Ex. Cistus, Helianthemum : a small family ; the flowers often showy. No im- portant properties. Several exude a balsamic resin, such as Lada- num from a Cistus of the Levant. 759. Ol'd. Droscracese (Sundew Family). Small herbs, growing in swamps, usually covered with gland-bearing hairs; with the leaves rolled up from the apex to the base in vernation (circinnate) : stip- ules none, except a fringe of hairs or bristles at the base of the petioles. Calyx of five equal sepals, persistent. Corolla of five regular petals, withering and persistent, convolute in estivation. Stamens as many as the petals and alternate with them, or some- times two or three times as many, distinct, withering; anthers ex- trorse. Styles three to five, distinct or nearly so, and each two- parted (so as to be taken for ten styles, Fig. 510), and these divis- ions sometimes two-lobed or many-cleft at the apex. Fruit a one- celled capsule, opening loculicidally by three to five valves, with three to five parietal placentas; in Dionsea membranaceous, burst- ing irregularly, and with a thick placenta at the base. Seeds usu- ally numerous. Embryo small, at the base of cartilaginous or fleshy albumen. — Ex. Drosera, the Sundew; and Dionoea (Venus’s Fly- trap, Fig. 297, 298), so remarkable for its sensitive leaves, which suddenly close when touched. The styles of the latter are all united into one. 7G0. Ol'd. Pamassiaccx is for the present made for the genus Par- nassia, which was formerly appended to Droserace® (for no good reason), and has since been placed by some next to Hypericace®, by others referred to Saxifragaee®. It is remarkable for having the four or five stigmas situated directly over the parietal placent® (p. 294, note), and for the curious appendages resembling sterile sta- mens before each petal (Fig. 380, 381). 7G1. Ol'd. Ilypericaceac (St. Johnswort Family). Shrubs or herbs, with a resinous or limpid juice, and opposite entire leaves, destitute of stipules, and punctate with pellucid or blackish dots. Flowers regular. Calyx of four or five persistent sepals, the two exterior often smaller. Petals four or five, convolute in .estivation, often beset with black dots. Stamens commonly polyadelphous and numer- ous. Ovary one-celled with parietal placent®, or 4 —5-cellcd (Fig. 375, 497, 498, 508, 509). Capsule with septicidal dehiscence (Fig. 582), many-seeded. — Ex. Hypericum (St. Johnswort) is the type of this small family. Embryo straight; albumen little or none.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 395 The plants yield a resinous acrid juice, and a bitter, balsamic ex- tractive matter. 762. Ord. Elatinacctc (Waterwort Family). Small annual weeds with membranaceous stipules between the opposite leaves, and mi- nute axillary flowers. Sepals and petals three to five. Stamens as many or twice as many as the petals, distinct. Capsule 2 - 5-eelled, septicidal or septifragal; the numerous seeds attached to a persist- ent central axis. Albumen none. — Ex. Elatine is the type of this order, containing a few insignificant weeds. 763. Ord. CaryophyllaccfE (Pink Family). Herbs, with opposite entire leaves ; the stems tumid at the nodes. Flowers regular. Calyx of four or five sepals. Corolla of four or five petals, or sometimes wanting. Stamens as many, or commonly twice as many, as the petals, sometimes reduced to two or three. Styles two to five, stigmatose down the inside. Ovary mostly one-celled, with a central or basilar placenta, forming a pod in fruit. Embryo periph- eric, curved or coiled around the outside of mealy albumen (Fig. 620, 621, 726). -—• There are five principal suborders, viz.: — 7 64. Sllbord. Silent® (Pink Family proper) ; in which the sepals are united into a tube, and the petals (mostly convolute in aestiva- tion) and stamens are inserted on the stipe of the ovary, the former with long claws (Fig. 432, 449), and there are no stipules. — Ex. Silene, Dianthus (Pink, Carnation). 765. Sllbord. Alsine® (Chickweed Family)-, in which there are no FIG. 720. Ilypericum perforatum (St Johns wort). 721. Its tricarpellary pistil. 722. Cross-section of the capsule. 723. Vertical section of a seed and iw> einbv, o.396 ILLUSTRATIONS OF THE NATURAL ORDERS. stipules, tlie ovary is sessile, the sepals and petals (imbricated in aestivation) are nearly or quite distinct; the petals destitute of claws; and the stamens are inserted into the margin of a small hypogynous disk, which, however, occasionally coheres with the base of the calyx, and becomes perigynous. — Ex. Stellaria, Arenaria, &c. (Chick- a one-seeded utricle — Ex. Paronychia and Anychia. Spergula has conspicuous petals, and many-seeded capsules ; and so differs from Alsinete only in its stipules. Insignificant weeds. 767. Sllbord. Scleranthcfe (Knau'cl Family) is like the last, only there are no stipules. — Ex. Scleranthus. 768. Sllbord, Molluginc® (Carpet-treed Family) is apetalous with- out stipules, and has the stamens alternate with the sepals when of the same number ; thus effecting a transition to 769. (It'd. PortulacaceSE (Purslane Family). Succulent or fleshy herbs, with entire exstipulate leaves and usually ephemeral flowers. Calyx mostly of two or three sepals, sometimes cohering with the base of the ovary. Petals five, or rarely more numerous, sometimes none. Stamens variable in number, but when equal to the petals situated opposite them. Styles two to eight, united below. Capsule FIG. 724. Moehringia lateriflora. 725 A magnified flower. 726. Magnified section of a seed, showing the cmhryo coiled into a ring around tho albumen. 727. Vertical section of a pistil of Spergularia. weeds). Some are ornamental; others, such as the common Chickweed, are in- significant weeds. 766. Subord. Illc- ccbrctc (Knotwort Family) ; differing from the last main- ly in having sca- rious stipules ; the sepals often united below ; the petals often wanting or ru- dimentary ; the sta- mens manifestly pe- rigynous ; and the fruit more commonlyEXOGENOUS OK DICOTYLEDONOUS PLANTS. 397 with few or numerous seeds, attached to a central basilar placenta, often by slender funiculi. Seed and embryo as in Caryophyllacete. — Ex. Portulaca (Purslane, Fig. 389, 588) Claytonia. Chiefly natives of dry places in the warmer parts of the world; except Claytonia. Insipid or slightly hitter: several are pot-herbs, as the Purslane. Some are ornamental. The farinaceous root of Lewisia 7:8 rediviva, a native of the dry interior plains of Oregon, is an impor- tant article of food with the natives. 770. 0I'll. Mesembryanthemacca! (Fig-Marigold Family) consists of succulent plants, with showy flowers opening only under bright sun- shine, containing an indefinite number of petals and stamens, and a many-celled and many-seeded capsule: otherwise much as in Caryo- phyllacem.—Ex. Mesembryanthemum (Fig-Marigold, Ice-plant); chiefly natives of the Cape of Good Hope, flourishing in the most arid situations. 771. Ol'd. MalvaceSB (Mallow Family). Herbs, shrubs, or rarely trees. Leaves alternate, palmately veined, with stipules. Flowers ■regular, often with an involucel, forming a double calyx. Calyx mostly of five sepals, more or less united at the base, valvate in FIG. 728. Flower of the Purslane; the calyx cut away at the point where it adheres to the ovary, and laid open. 729. A capsule (pyxis) of the same, transversely dehiscent. 730. Clay- tonia Yirginica (Spring-Beauty). 731. Diagram of the flower. 732. Young fruit and the per- sistent two-leaved calyx. 733. Section of the dehiscing capsule. 734. A seed. 735. The same, vertically divided. 736. The embryo, detached. 34398 ILLUSTRATIONS OF THE NATURAL ORDERS. aestivation. Petals as many as the sepals, convolute in estivation, hypogynous. Stamens indefinite, monadelphous, united with the claws of the petals: anthers reniform, confluently one-celled. Pollen hispid (Fig- 483). Ovary several-celled, with the placentae in the axis; or ovaries several. Fruit capsular, or the carpels separate or separable. Seeds with a little mucilaginous or fleshy albumen. Embryo large, with foliaceous cotyledons, variously incurved or folded. — Ex. Malva (Mallow), Althaea (Hollyhock), Gossypium (Cotton), &c.. a rather large and important family, the herbage, &c. commonly abounding in mucilage, and entirely destitute of un- wholesome qualities. The unripe fruit of Abelmoschus or Hibiscus esculentus (Okra) is used in soups. Althaea officinalis is the Marsh Mallow of Europe, the Guimauve of the French. The tenacious inner bark of many species is employed for cordage. Cotton is the hairy covering of the seeds of Gossypium : the long and slender tubes, or attenuated cells, collapse and twist as the seed ripens, which renders the substance capable of being spun. Cotton-seed yields a good fixed oil. Some species are cultivated for ornament. 772. Ol'd. Byttneriacea! is distinguished from the foregoing by its usually definite stamens, and the two-celled anthers (the cells par- allel), with smooth pollen. — A Melochia and a Hermannia are found in Texas. The rest of the order is tropical or subtropical. Chocolate is made of the roasted and comminuted seeds of Theo- broma Cacao (a South American tree), mixed with sugar, arnotto, vanilla, and other ingredients. The roasted integuments of the seeds, also, are used as a substitute for coffee. ^FIG. 737. The Marsh Mallow (Althaea officinalis). 738. One of the kidney-shaped one-celled anthers, magnified. 739. The pistils, magnified. 740. Capsule of Hibiscus Moscheutos, with the persistent calyx and involuceL 741. The same, loculicidally dehiscent.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 399 773. Ord. Stcrculiaccffi, very closely allied to the last two, and con- sisting of tropical trees, possesses the same mucilaginous properties (as well as oily seeds), with which bitter and astringent qualities are often combined. The seeds of Bombax, the Silk-cotton tree, are enveloped in a kind of cotton, which belongs to the endocarp and not to the seed; and the hairs, being perfectly smooth and even, can- not be spun. Canoes are made from the trunk of the huge Bombax Ceiba, in the West Indies. To this order belongs the famous Baobab, or Monkey-bread, of Senegal (Adansonia digitata), some trunks of which are from sixty to eighty feet in circumference ! The fruit resembles a gourd, and serves for vessels ; it contains a subacid and refrigerant, somewhat astringent pulp ; the mucilagi- nous young leaves are also used for food in time of scarcity; the dried leaves (Lalo) are ordinarily mixed with food, and the bark furnishes a coarse thread, which is made into cordage or woven into cloth. Cheirostemon platanoides is the remarkable Hand-flower tree of Mexico. A plant of the family (Fremontia, Torr.) nearly allied to Cheirostemon has been found in California, by Fremont. 774. Ord. Tiliacctc (Linden Family). Trees or shrubby plants, with alternate leaves, furnished with deciduous stipules, and small 747 742 743 744 flowers. Calyx deciduous. Petals sometimes imbricated in asstiva- FIG. 742. Flowering branch of Tilia Americana, the common American Linden; the flower- stalk cohering with the bract. 743. One of the clusters of stamens adhering to the petaloid scale. 744. The pistil. 745. Cross-section of the fruit, which has become one-celled by the obliteration of the partitions, and one-seeded. 746 Vertical section of the seed, magnified, to show the large embryo with its taper radicle and foliaceous crumpled cotyledons. (A better section of the seed, cut in the direction across the cotyledons, is shown in Fig. 599.) 747. Diagram of the flower.400 ILLUSTRATIONS OF THE NATURAL ORDERS. tion. Stamens indefinite, often in three to five clusters, distinct or somewhat united, one of each parcel often transformed into a peta- loid scale (Fig. 383, 743): anthers two-celled. Styles united into one. Fruit two to five-celled, or, by obliteration, one-celled when ripe. In other respects nearly as in Malvaceae. — Tilia, the Linden, or Lime-Tree, represents the order in northern temperate regions ; the other genera are tropical. All are mucilaginous, with a tough fibrous inner bark. From this bast or bass of the Linden, the Rus- sian mats, &c. are made, whence the name of Basswood. Gunny- bags and fishing-nets are made in India from the bark of Corcliorus capsularis ; the fibre of which, called Jute, is spun and woven. The light wood of the Linden is excellent for wainscoting and carv- ing : its charcoal is used for the manufacture of gunpowder. It is said that a little sugar may be obtained from the sap: and the honey made from the odorous flowers is thought to be the finest in the world. The acid berries of Grewia sapida are employed in the East in the manufacture of sherbet. 775. Ol'd. DipterOCarpcfE, allied in some respects to Tiliaceas, con- sists of a few tropical Indian trees, with a resinous or balsamic juice. Dryobalanops aromatien, a large tree of Sumatra and Borneo, yields in great abundance camphor oil and solid camphor: both are found deposited in cavities of the trunk. It is more solid than common camphor, and is not volatile at ordinary temperatures. It bears a high price, and is seldom found in Europe or this country, but is chiefly carried to China and Japan. Shorea robusta yields the Dammer-pitch. Vateria Indica exudes a kind of copal, the Gum Animi of commerce ; and a somewhat aromatic fatty matter, called Piney Tallow, is derived from the seeds. 776. Ord. Gllttifera, or Clusiaceas, consists of tropical trees, with a yellow resinous juice, opposite and coriaceous entire leaves, and large flowers with many stamens, little distinction between the sepals and petals, no styles, an indehiscent fruit, and seeds with a peculiar undivided fleshy embryo. It has been associated witli Ily- perieaceoa, but is more related to the ensuing families. The resin- ous juice is acrid and drastic; that of a Ceylonese tree of the order yields Gamboge. It is remarkable that such an order should pro- duce one of the most esteemed fruits, viz. the Mangosteen, yielded by Garcinia Mangostana of Malacca, and also the Mammee-apple, &c. 777. Ol’d. Camelliacca: {Camellia or Tea Family). Trees or shrubs, with a watery juice, alternate simple leaves without stipules, andEXOGENOUS OR DICOTYLEDONOUS PLANTS. 401 large and showy flowers. Calyx of three to seven coriaceous and concave imbricated sepals. Petals five or more, imbricated in esti- vation. Stamens hypogynous, indefinite, monadelphous or polyadel- phous at the base. Capsule dehiscent, several-celled, usually with a central column. Seeds few in each cell, large, often winged, with or without albumen. — The Camellia and the closely related Tea- plant form the type of this family, to which belong our Gordonia and Stuartia. The leaves of Tea contain a peculiar extractive mat- ter, and an ethereal oil; its moderately stimulant properties are said to become narcotic in very hot climates. 778. Ol’d. TcmstramiacetE, chiefly tropical, with which the last has been confounded, by its aspect, its commonly polygamous flowers, and more or less gamopetalous corolla, &c., appears on the whole to be more allied to' the Ebenaceae and Symplocineaa. 779. Ord. AlirantiacetC (Orange Family). Trees or shrubs, with alternate leaves (compound, or with jointed petioles), destitute of stipules, dotted with pellucid glands full of volatile oil. Flowers fragrant. Calyx short, urceolate or campanulate. Petals three to five. Stamens inserted in a single row upon a hypogynous disk (Fig. 434), often somewhat monadelphous or polyadelphous. Style cylindrical. Fruit a many-celled berry, with a leathery rind, filled with pulp. Seeds without albumen. — Ex. Citrus, the Orange and Lemon. Nearly all natives of tropical Asia; now dispersed through- out the warmer regions of the world, and cultivated for their beauty and fragrance, and for their grateful fruit. The acid of the Lemon, Lime, &e. is the citric and the malic. The rind abounds in a vola- tile oil (such as the Oil of Bergamot from C. Limetta), and an aro- matic, bitter principle. 780. Ord. Meliaceat. Trees or shrubs, with alternate, usually com- pound leaves, destitute of stipules. Calyx of three to five sepals. Petals three to five. Stamens twice as many as the petals, mona- delphous, inserted with the petals on the outside of an hypogynous disk ; the anthers included in the tube of filaments. Ovary several- celled, with one or two ovules in each cell: styles and stigmas united into one. Fruit a drupe, berry, or capsule; the cells one-seeded. Seeds without albumen, wingless. — Ex. Melia Azedarach (Pride of India), naturalized, as an ornamental tree, in the Southern States. An acrid and bitter pi-inciple pervades this tropical order. 781. Ord. Ccdrelacctc (.Mahogany Family). Trees (tropical or Australian), with hard and durable, usually fragrant and beautiful 34*402 ILLUSTRATIONS OF THU NATURAL ORDKRS. wood ; differing botanically from Meliaceue chiefly by their capsular fruit, with several winged seeds in each cell. —- Ex. The Mahogany (Swietenia Mahagoni) of tropical America, reaching to East Flor- ida. Bark, &c. bitter, astringent, tonic, often aromatic and febrifugal. 782. Ord. Liliacca; (Flax Family). Herbs, with entire and sessile leaves, either alternate, opposite, or verticillate, and no stipules, ex- cept minute glands. Flowers regular and symmetrical. Calyx of three or five persistent sepals, strongly imbricated. Petals as many as the sepals, convolute in aestivation. Stamens as many, as the petals, and usually with as many intermediate teeth representing an abortive series (Fig. 423), all united at the base into a ring, hypogy- nous. Ovary with as many styles and cells as there are sepals, each cell with two suspended ovules ; the cells in the capsule each more or less divided into two, by a false par- tition which grows from the back (Fig. 750); the spurious cells one-seeded. Em- bryo straight: cotyledons flat, fleshy and oity, surrounded by a thin albumen. — Ex. Linum, the Flax. The tough woody fibre of the bark (flax) is of the highest importance : the seeds yield a copious mucilage, and the fixed oil expressed from them is applied to various uses in the arts. The general plan of the flower is the same in the succeeding orders. FIG. 748. Flowers of the common Flax. 749. Vertical section of a flower. 750. Diagram of the same, in a transverse section. 751. Its 10-celled capsule transversely divided. 752. Similar section of the incompletely 10-celled capsule of Linum perenne.EXOGENOUS OK DICOTYLEDONOUS TLANTS. 403 783. Ord. GeraniacetC (Cranesbill Family). Herbs or shrubby plants, commonly strong-scented; with pahnately veined and usually lobed leaves, mostly with stipules ; the lower opposite. Flowers regular. — Calyx of five persistent sepals, imbricated in aestivation. Petals five, with claws, mostly convolute in aestivation. Stamens 10, the five exterior hypogynous, occasionally sterile ; the filaments all broad and often united at the base ; five glands within and alternate with the petals. Ovary of five two-ovuled carpels, attached to the base of an elongated axis (gynobase, Fig. 430, 431) to which the styles cohere: in fruit the distinct one-seeded carpels separate from the axis, by the twisting or curling back of the persistent indurated styles from the base upwards. Seeds with no albumen : cotyledons convolute and plaited together, bent on the short radicle. For the plan of the blossom see p. 2G4, and Fig. 421. Our cultivated Geraniums, so called, from the Cape of Good Hope, are species of Pelargonium. The roots are simply and strongly astringent. The foliage abounds with resinous matter and an ethereal oil, on which the aroma depends. 784. Ord. Balsaminacea) (Balsam Family). Annual herbs, with succulent stems filled with a watery juice. Leaves simple, without stipules. Flowers irregular, and one of the colored sepals spurred or saccate. Stamens five, cohering by an internal appendage. FIG. 753. Radical leaf of Geranium maculatum (Cranesbill). 754. A flowering branch. 755. A flower with the calyx and corolla removed, showing the stamens, &c. 756. The pistil in fruit; the indurated styles separating below from the prolonged axis, and curving back elastically, carrying with them the membranous carpels. 757. A magnified seed. 758. A cross-section of the same, showing the folded and convolute cotyledons.404 ILLUSTRATIONS OF THE NATURAL ORDERS. Compound ovary five-celled; stigmas sessile. Capsule bursting elastically by five valves. Seeds several, without albumen, and with a thick straight embryo. — Ex. Impatiens, the Balsam, or Touch- me-not. Remarkable for the elastic force with which the capsule bursts in pieces, and expels the seeds. Somewhat differently irreg- ular blossoms are presented by the 1 785. Ol'd. Troptcolaceaf {Indian-Cress or Nasturtium Family). Straggling or twining herbs, with a pungent watery juice, and peltate or palmate leaves. Flowers irregular. Calyx of five colored and united sepals, the lower one spurred. Petals five; the two upper arising from the throat of the calyx, remote from the three lower, which are stalked. Stamens eight, unequal, distinct. Ovary three- lobed, composed of three united carpels ; which separate from the common axis when ripe, are indeliiscent, and one-seeded. Seed filling the cell, without, albumen: cotyledons very large and thick. — Ex. Tropseolum, the Garden Nasturtium, from South America, where there are a few other species, one of which bears edible tubers. They possess the same acrid principle and antiscorbutic properties as the Cruciferai. The unripe fruit of Tropfeolum majus is pickled, and used as a substitute for capers. 78G. Ord. Limmintliaceai differs from the last only in its regular and symmetrical blossoms, and the erect instead of suspended seeds ; the calyx vaivate in aestivation. — Ex. Limnanthes of California (some- times cultivated as an ornamental annual), and FIcerkea of the Northern United States. 787. Ol'd. Oxalidaccai ( Wood-Sorrel Family). Low herbs, with an acid juice, and alternate compound leaves; the leaflets usually ob- cordate. Flowers regular, of the same general structure as in Li- nacerc, &c., except the gynrecium, which in fruit forms a membra- naceous five-lobed and five-celled, several-seeded capsule. Seeds with a fleshy outer coat, which bursts elastically when ripe, with a large and straight embryo in thin albumen. — Ex. Oxalis, the Wood-Sorrel. The herbage is sour, as the name denotes, and con- tains oxalic acid. The foliage is remarkably sensitive in some spe- cies. The tubers of some South American species, filled with starch, have been substituted for potatoes. 788. Ord. ZygopliyllaccU! differs from the last in the opposite, mostly abruptly pinnate leaves, distinct stamens (the filaments com- monly furnished with an internal scale, Fig. 379), and the styles united into one. — Ex. Tribulus and Kallstroemia (introduced intoEXOGENOUS OR DICOTYLEDONOUS PLANTS. 405 the Southern States) are exalbuminous; the latter is 10-coccous, just as Linum is, by a false partition. Guaiacum, Larrea (Creo- sote-plant of New Mexico and Texas), and the rest of the family, have a corneous albumen. The wood of Guaiacum (Lignum-vittz) is extremely hard and heavy, and yields a gum-resinous, bitter, and acrid principle ( Gum Guaiacum), well known in medicine. 789. Ord, Simarubace* (Quassia Family), of tropical shrubs or trees, resembles the last in generally having a peculiar scale to the filaments. It is, however, more nearly related to the next order, but its apocarpous ovaries are one-ovuled, and the (mostly com- pound) leaves are dotless. The wood, &c. is intensely bitter: that of Quassia amara is used as a stomachic tonic. The seed of Cedron (Simaba Cedron) is the famous antidote for the bites of venomous snakes in Central America. 790. Ol’d. RutaCCEC (Rue Family). Herbs, shrubs, or trees ; the leaves punctate with pellucid dots, and without stipules. Calyx of four or five sepals. Petals four or five, or rarely none. Stamens 760 759 764 765 as many or twice (rarely three times) as many as the petals, insert- FIG. 759. A flowering branch of Zanthoxylum Americanum (the Northern Prickly Ash). 760. A piece of a leaf, to show the pellueid dots. 761. Staminate flower. 762. A pistillate flower, the sepals spread open. 763. Two of the pistils; one of them divided vertically to show the ovules. 764. A branch in fruit. 765. One of the dehiscent pods, and the seed. 766. Yer- tical section of an unripe pod and seed; the latter pendent from a descending funiculus, show- ing a slender embryo in copious albumen.406 ILLUSTRATIONS OF THE NATURAL ORDERS. ed on the outside of a hypogynous disk. Ovary three- to five-lobed, three- to five-celled, with the styles united, or distinct only at the base, or the ovaries nearly separate, during ripening usually sepa- rating into its component carpels, which are dehiscent by one or both sutures. Seeds few or single, mostly with albumen ; and a curved embryo. — Ex. Ruta (the Rue), Dictamnus (Fraxinella), of Europe. Diosma and its allies, of the Cape of Good Hope, New Holland, &c., form a group, or suborder (Diosmeje) from which the Zantiioxyle.e (or Priekly-Ash Family) differs only in being gen- erally dioecious; but have no claim to be ranked as a distinct order. Strong-scented, bitter-aromatic, often very pungent, from an atrid volatile oil (as Rue and Zanthoxylum) ; also bitter. Some contain a bitter alkaloid, and are febrifugal. The most important is the Galipea, which furnishes the Angostura bark. 791. Orel. Aliacartliacete (Cashew Family). Trees or shrubs, with a resinous or milky, often acrid juice, which turns blackish in dry- ing ; the leaves alternate, without stipules, and not dotted. Flowers small, often polygamous or dioecious. Calyx of three to five sepals, united at the base. Petals, and usually the stamens, as many as the sepals, inserted into the base of the calyx or into an hypogynous disk. Ovary one-celled, but with three styles or stigmas, and a single ovule. Fruit a berry or drupe. Seed without albumen. Embryo curved or bent. — Ex. Rhus, Anacardium (the Cashew), Pistacia. Chiefly tropical; except Rhus. The acrid resinous juice is used in var- nishes ; but it often contains a caustic poison. Even the exhalations from Rhus Toxicodendron (Poison Oak, Poison Ivy), and R. vene- nata (Poison Sumach, Poison Elder), as is well known, severely affect many persons, producing a kind of erysipelas. Their juice is a good indelible ink for marking linen. But the common Sumachs (R. typhina and R. glabra) are innocuous ; their bark or leaves are used for tanning, and their sour berries (which contain bimalate of lime) for acidulated drinks. The oily seeds of Pistacia vera (the Pistachio-nut) are edible; and the drupe of Mangifera Indica (Mango) is one of the most grateful of tropical fruits. The kernel of the Cashew-nut (Anacardium occidental) is eatable ; and so is the enlarged and fleshy peduncle on which the nut rests : but the coats of the latter are filled with a caustic oil, which blisters the skin ; while from the bark of the tree a bland gum exudes. 792. Ol'd, Bimeraccffi, including a great part of what were formerly called Terebinthaceai, consists of tropical trees, with a copious resin-EXOGENOUS OR DICOTiXEDONOUS PLANTS. 407 ous juice, compound leaves usually marked with pellucid dots, and small flowers ; with valvate petals, a two- to five-celled ovary, and drupaceous fruit. Their balsamic juice, which flows when the trunk is wounded, usually hardens into a resin. The Olibanum, used as a fragrant incense, the Balm of Gilead, Balsam of Mecca, Myrrh, and the Bdellium, are derived from Arabian species of the order ; the East Indian Gum Elem.i, from Canarium commune ; Balsam of Acouchi, and similar substances, from various American trees of this family. 793. Ord. Arayridacetc consists of a few West Indian plants, inter- mediate as it were between Burseraceae and Leguminosae, and dis- tinguished from the former chiefly by their simple and solitary ovary. — Very probably this and the two last are to be recombined. • 763 769 794. Ord. Vitacca; ( Vine Family). Shrubby plants, climbing by tendrils, with simple or compound leaves, the upper alternate. FIG. 767. A branch of the Grape-Vine. 768. A flower; the petals separating from the base, and falling off together without expanding. 769. A flower from which the petals have fallen; the lobes of the disk seen alternate with the stamens. 770. Vertical section through the ovary and the base of the flower: a, calyx, the limb of which is a mere rim : b, petal, having the stamen, c, directly before it; and the lobes of the disk are shown between this and the ovary. 771 A seed. 772. Section of the seed, showing the thick crustaceous testa, and the albumen, at the base of which is the minute embryo. 772;. A horizontal plan of the flower.408 ILLUSTRATIONS OP THE NATURAL ORDERS. Flowers small, often polygamous or diceeious. Calyx very small, filled with a disk ; its limb short or obsolete. Petals 4 or 5, valvate in aestivation, sometimes cohering by their tips, and caducous. Sta- mens as many as the petals and opposite them ! Ovary two-celled, with two erect ovules in each cell. Fruit a berry. Seeds with a bony testa, and a small embryo in hard albumen. — Ex. Yitis (the Vine), Ampelopsis (the Virginia Creeper). The fruit of the Vine is the only important product of the order. The acid of the grape, which also pervades the young shoots and leaves, is chiefly the tar- taric. Grape-sugar is very distinct from cane-sugar, and the only kind that can long exist in connection with acids. 795. Orel, Chamnacetc {Buckthorn Family). Shrubs or trees, often with spinose branches; the leaves mostly alternate, simple. Flowers small. Calyx of four or five sepals, united at the base, valvate in aestivation. Petals four or five, cucullate or convolute, inserted on the throat of the calyx, sometimes wanting. Stamens as many as the petals, inserted with and opposite them! Ovary sometimes coherent with the tube of the calyx, and more or less immersed in a fleshy disk, with a single erect ovule in each cell (Fig. 405, 43G). Seeds not arilled. Embryo straight, large, in sparing albumen. — Ex. Rhamnus (Buckthorn) is the type of the order. The berries of most species are somewhat nauseous ; but those of Zizyphus are edible. Jujube paste is prepared from those of Z. Jujuba and Z. vulgaris of Asia. Syrup of Buckthorn and the pigment called Sap- green. are prepared from the fruit of Rhamnus catharticus. The herbage and bark in this order are more or less astringent and bitter. An infusion of the leaves of Ceanothus Americanus (thence called New Jersey Tea) has been used as a substitute for tea, and a very poor one it is. 796. Orel. CelaslracetB (Spindle-tree Family). Shrubs or trees, with alternate or opposite simple leaves. Calyx of four or five sepals, imbricated in .estivation. Petals as many as the sepals, in- serted under the flat expanded disk which closely surrounds the ovary, imbricated in {estivation. Stamens as many as the petals, and alternate with them, inserted on the margin or upper surface of the disk. Ovary free from the calyx. Fruit a capsule or berry, with one or few seeds in each cell. Seeds usually arilled, albumi- nous, with a large and straight embryo. — Ex. Celastrus, Euonymus (Burning Bush, Spindle-tree, Strawberry-tree) ; all somewhat bitter and acrid; but of little economical importance. The red or crim-EXOGENOUS OR DICOTYLEDONOUS PLANTS. 409 son capsules and bright scarlet arils of several species present a striking appearance when the fruit is ripe. 797. Ol'd. MalpighiacecE is a large tropical family (with one or two representatives in Texas), of trees, shrubs, and twining plants, with opposite entire leaves, unguiculate petals, and solitary seeds with a curved embryo; differing from the next in the want of a disk, the more symmetrical flowers, &c. 798. Ol’d. Sapilldaceai {Soapberry Family). Trees, shrubs, or climb- ers with tendrils, rarely herbs, with simple or compound leaves, and mostly unsymmetrical or irregular flowers ; the sepals and petals imbricated in aestivation. Stamens 5 to 10, inserted on a fleshy perigynous or hypogynous disk. Ovary 2-3-celled, 2-3-lobed, with one or two (in Staphylea several) ovules in each cell; the embryo (except in Staphylea) curved or convolute and without albumen. — Includes a variety of forms, the greater part of which may be ranged under the following suborders, which have been taken for orders. 777 773 774 775 799. Subord. Staphyleacecc (Bladdernut Family) has opposite com- pound leaves with stipules and stipels, regular and perfect pentan- FIG. 773. Flowering branch of iEsculus Pavia (Red Buckeye). 774. A flower. 775. Flower with the calyx and two of the petals removed. 776. A ground-plan of the flower, showing that its parts are unsymmetrical. 777. Vertical section of an ovary, showing two of the cells with a pair of ovules in each, one ascending, one descending. 778. Cross-section of an ovary. 779. Cross-section of the immature fruit; only one fertile seed; the others abortive. 780. The dehiscent fruit. 35410 ILLUSTRATIONS OF THE NATURAL ORDERS. drous flowers, three partly united pistils with several ovules in each, and large bony seeds, with a straight embryo in scanty albumen. — Ex. Staphylea. 800. Subord. SapindCEB (Soapberry Family proper) has alternate, or in the Horsechestnut tribe opposite leaves, without stipules, more or less unsymmetrieal or irregular and polygamous flower.', exalbu- minous seeds, and a curved embryo with thickened cotyledons. — Mostly tropical, except the Horsechestnut and Buckeyes (HSsculus), which have been deemed a separate family (Hippocastanece). Their very large and fleshy embryo has the cotyledons more or less con- solidated (Fig. 629, 630). The seeds of the Horsechestnut are nu- tritious, but contain an intensely bitter principle which is more or less noxious. Those of JE. Pavia are used to stupefy fish. The root, according to Elliott, is employed as a substitute for soap. The fruit of Sapindus is used for the same purpose, whence the name of Soapberry. 781 788 733 801. Sllbord. Accriuett (Maple Family) has opposite (simple or compound) leaves without stipules, a 2-lobed and 2-winged fruit FIG. 781. A branch of Acer dasycarpum (the White Soft Maple) •with staminate flowers. 782. A separate, enlarged, staminate flower. 783. Branch with pistillate flowers. 781 A separate fertile flower. 785. The same, enlarged, with the calyx cut away. 786. A cluster showing the fruiting ovaries expanding into wings (reduced in size). 787. Ripe fruit; one of the samaras cut open to show the seed. 788. A leaf.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 411 forming two samaras, and an embryo with long and thin, variously curved or coiled cotyledons (Fig. 103 -105) ; otherwise nearly as in the true Sapindacese. — Ex. Acer, the Maple ; useful timber-trees of northern temperate regions. Sugar is yielded by the vernal sap of Acer saccharinum, and in less quantity by all the species. 802. Ol'd. Polygalacc®. Herbs or shrubby plants, with simple entire leaves, destitute of stipules. Flowers perfect, unsymmetrieal, and irregular, somewhat papilionaceous in appearance, but of wide- ly different structure. Calyx of five irregular sepals ; the odd one superior, the two inner ('wings) larger, and usually petaloid. Petals usually three, inserted on the receptacle, more or less united; the anterior (keel) larger than the rest. Stamens six to eight, combined in a tube, which is split on the upper side, and united below with the claws of the petals: anthers innate, mostly one-celled, opening by a pore at the apex. Ovary compound, two-celled, with a single suspended ovule in each cell: style curved and often hooded. 731 790 Capsule flattened. Seeds usually with a caruncle. Embryo straight, large, in fleshy, thin albumen. — Ex. Polygala is the principal genus of the order. The plants yield a bitter principle with some acrid FIG. 789. Polygala paucifolia. 790. A flower, enlarged. 791. The calyx displayed. 792. The corolla and stamineal tube laid open. 793. The pistil and the free portion of the stamens. 794. Vertical section of the ovary. 795. Vertical section of the seed, showing the large embryo and scanty albumen.412 ILLUSTRATIONS OF THE NATURAL ORDERS. extractive matter. Polygala Senega (Seneca Snakeroot) is the most important medicinal plant of the family. Other species are employed medicinally in Brazil, Peru, Nepaul, &c.; where, like our own, they are reputed antidotes to the bites of venomous reptiles. 803. Ol'd. Kraincriiicea; (Rhatamj Family) consists of the genus Krameria only, which has ordinarily been annexed to the Polyga- lacem ; but the position of the parts of the flower is more like that of the Leguminosre, having the odd sepal inferior, a simple unilocu- lar pistil, and an exalbuminous seed. In fact it is technically distin- guishable from the latter chiefly by the hypogynous stamens and the want of stipules. The roots contain a red coloring matter, and are astringent without bitterness. Bluitany-root, used to adulterate port- wine, and as an ingredient in tooth-powders, &c., is the produce of K. triandra of Peru. That of our own Southern species possesses the same properties. 804. Ord. kgumillOSi® (Pulse Family). Herbs, shrubs, or trees, with alternate and usually compound leaves, furnished with stipules. FIG. 796. A flowering branch of Lathyrus palustris, var. myrtifolius. 797. The corolla displayed : a, the vexillum or standard; b, the alee or wings ; c, the two petals of the carina or keel.' 798. The keel-petala in their natural situation. 799. The stamens and pistil, en- larged ; the sheath of filaments partly turned back.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 413 Calyx mostly of five sepals, more or less united; the odd sepal in- ferior (Fig. 358). Corolla of five petals, either papilionaceous or regular. Stamens perigynous, or sometimes hypogynous. Ovary single and simple. Fruit a legume, various forms of which are shown in Fig. 580, 581, 800-807. Seeds destitute of albumen, or with a mere vestige of it. -— This immense family is divided into three principal suborders ; viz.: — 803 80/ 800 801 802 801 80S 806 805. Suliord. Papilionacctc (Pulse Family proper), which is charac- terized by the papilionaceous corolla, — the vexillum always exter- nal in asstivation (471, Fig. 392), — ten diadelphous (Fig. 461), monadelphous (Fig. 462), or rarely distinct, perigynous stamens, and the radicle bent on the large cotyledons. Leaves (rarely sim- ple) only once compound ; the leaflets very rarely toothed or lobed. 806. Subord. CaesalpinetE (to which Cassia, Cercis, and the Honey- Locust belong) : here the corolla gradually loses its papilionaceous character, and always has the vexillum, or superior petal, covered by the lateral ones in aestivation ; the stamens are distinct, and the embryo straight. The leaves are often bipinnate. 807. Subord, Miuiosett (a large group, to which the Acacia and the Sensitive Plant belong) has a perfectly regular calyx and corolla, the latter mostly valvate in aestivation and hypogynous, as well as the stamens, which are sometimes definite, but often very numerous and the embryo is straight. The leaves are frequently tripinnate. FIG. 800. Open legume of the Pea. 801. Loment of Desmodium. 802. Loment of Mi- mosa : 6, one of its dehiscent joints which has fallen away from the persisting border or frame- (replum), seen in 803. 804. The jointed indehiscent legume of Sophora. 805 A legume of Astragalus, cut across near the summit, to show how it becomes partly or entirely two-celled by the introflexion of the dorsal suture. 806. Similar view of a legume of Phaca, where the ventral suture is somewhat introflexed. 807. A legume of Medicago scutellata, spirally coiled\ into a globular figure. 35*414 ILLUSTRATIONS OF THE NATURAL ORDERS. 808. PapilionaceEe are found in every part of the world : Csesal- pineas and Mimosete are confined to *tlie tropical and warmer tem- perate regions. •— A full account of tlvc useful plants and products of this large order would require a separate volume. Many, such as Clover, Lucerne (Medicago sativa), &c., are extensively culti- vated for fodder; Peas and Beans, for pulse. The roots of the Licorice (Glycirrliiza glabra of Southern Europe) abound in a sweet mucilaginous juice, from which the pectoral extract of this name is prepared. The sweet pulp of the pods of Ceratonia Siliqua (Carob-tree of the South of Europe, &c.), like that of the Honey- Locust (Gleditschia), &c., is edible. The laxative pulp of Cathar- toearpus Fistula, and of the Tamarind, is well known ; the latter is acidulated with malic, and a little tartaric and citric acid.—A pecu- liar volatile principle (called Coumarin) gives its vanilla-like fra- grance to the well-known Tonka-bean, and to the Melilotus, or Sweet Cloyer. The flowers and seeds of the latter and of Trigonella cserulea give the peculiar odor to Scheipzeiger cheese. — Astringents and tonics are also yielded by this order: such as the African Ptero- earpus erinaceus, the hardened red juice of which is Gum Kino ; that of P. Draco, of Carthagena, &c., is Dragon’s Blood. The bark of most Acacias and Mimosas contains a very large quantity of tan- nin, and is likely to prove of great importance in tanning. The valuable astringent called Catechu is obtained by boiling and evap- orating the heart-wood of the Indian Acacia Catechu. — Legumi- nosa3 yield the most important coloring matters: such as the Brazil- wood, the Logwood of Campeachy (the peculiar coloring principle of which is called Hoematin), and the Bed Sandal-wood of Ceylon. Indigo is prepared from the fermented juice of the Indigofera tinc- toria (a native of India), and other species of the genus. This substance is highly azotized, and is a violent poison. — To the same order we are indebted for valuable resins and balsams ; such as the Mexican Copal, Balsam of Copawa of the West Indies, Para, and Brazil, the bitter and fragrant Balsam of Peru, and the sweet, fra- grant, and stimulant Balsam of Tolu. — It also furnishes the most useful gums; of which we need only mention Gum Tragacanth, derived from Astragalus verus of Persia, &c.; and Gum Arabic, the produce of certain African species of Acacia. The best is said to be obtained from Acacia vera, while Gum Senegal is yielded by A. Verek, and some other species. Algarobia dulcis, the Mes- quite of Texas and Mexico, yields a similar gum. The Senna ofEXOGENOUS OR DICOTYLEDONOUS PLANTS. 415 commerce consists of the leaves of several species of Cassia, of Egypt and Arabia. C. Maril^indica of this country is a succedane- um for the officinal article. — More acrid, or even poisonous prop- erties, are often met with in the order. The roots of Baptisia tinctoria (called Wild Indigo, because it is said to yield a little of that substance), of the Broom, and of the Dyers’ Weed (Genista tinctoria, used for dyeing yellow), possess such qualities ; while the seeds of Laburnum, &c. are even narcotico-acrid poisons. The ] branches and leaves of Tephrosia, and the bark of the root of ( Piscidia Erythrina (Jamaica Dogwood, which is also found in South- ern Florida), are commonly used in the West Indies for stupefying fish. Cowitch is the stinging hairs of the pods of species of Mu- euna. — Among the numerous valuable timber-trees, our own Locust (Robinia Pseudacacia) must be mentioned; and also the Rosewood of commerce, the produce of some Brazilian Cmsalpinieoe. Few orders furnish so many plants cultivated for ornament. 809. Ol'd. Rosacea! (Rose Family). Trees, shrubs, or herbs, with alternate leaves, usually furnished with stipules. Flowers regular. — Calyx of five (rarely three or four) more or less united sepals, and often with as many bracts. Petals as many as the sepals (rarely none), mostly imbricated in activation, perigynous. Sta- mens indefinite, or sometimes few, distinct. Ovaries with solitary Or few ovules: styles often lateral. Albumen none. Embryo straight, with broad and flat or plano-convex cotyledons (Fig. 108- lll).—This important order is divided into four suborders; viz.: — 810. Sllbord. Chrysobalanc® (Cocoa-plum Family). This is now generally taken as an independent order, intermediate between Leguminosse and Rosace*. Ovary solitary, free from the calyx, or else cohering with it at the base on one side only, containing two erect ovules : style arising from the apparent base. Fruit a drupe. Trees or shrubs. — Ex. Ohrysobalanus ; some species of which pro- duce an edible fruit. 811. Sllbord. Amygdalc® (Almond or Plum Family). Ovary soli- tary, free from the deciduous calyx, with two suspended ovules, and a terminal style. Fruit a drupe (Fig. 562). Trees or shrubs.— Ex. Amygdalus (the Almond, Peach), Prunus (the Plum), &c. 812. Subord. Rosace® proper. Ovaries several, numerous, or rarely solitary, free from the calyx (which is often bracteolate, as if j double), but sometimes enclosed in its persistent tube, in fruit becom- \ ing either follicles or achenia. Styles terminal or lateral. Herbs or ) \416 ILLUSTRATIONS OF THE NATURAL ORDERS. shrubs. — The three tribes of this suborder are: — Tribe 1. Spireme, where the fruit is a follicle. Ex. Spiraea and Gillenia. Tribe 2. Dryadeje, where the fruits are achenia, or sometimes little drupes, and when numerous crowded on an enlarged torus (Fig. 558, 550, 564, 565). Ex. Dryas, Agrimonia, Potentilla, Fragaria (Strawber- ry), Rubus (Raspberry and Blackberry). Tribe 3. Rose.®, where numerous achenia cover the hollow torus which lines the urn-shaped calyx-tube ; and the latter, being contracted at the mouth, and be- coming fleshy or berry-like, forms a kind of false pericarp ; as in the Rose (Fig. 429, 808). 813. Subord, Pome® (Pear Family). Ovaries two to five, or rare- ly solitary, cohering with each other and with the thickened and fleshy or pulpy calyx-tube ; each with one or two (in the Quince several) ascending seeds. Trees or shrubs. — _Er. Craftcgus (the Thom), Cydonia (the Quince), Pyrus (the Apple, Pear, &e.). 812 814. This important order is diffused through almost every part of the world ; but chiefly abounds in temperate climates, where it furnishes the most important fruits. It is destitute of unwholesome qualities, with one or two exceptions, viz. : — The bark, leaves, and kernel of Amygdalere contain prussic acid, or something of similar odor and analogous properties; as is exemplified by the Cherry-Laurel FIG. 808. Vertical section of an unexpanded Rose, showing the attachment of the carpels to the lining of the calyx-tube, and of the stamens and petals to its summit or edge. 809. Vertical section of the fruit of the Quince, exhibiting the carpels invested by the thickened calyx which forms the edible part of the fruit; one of the ovaries laid open to show the seeds. 810. A magnified seed; the rhaphe and chalaza conspicuous. 811. The embryo. 812. Cross- section of an apple. 813. Flower, &c. of the American Crab-apple (Pyrus coronaria).EXOGENOUS OR DICOTYLEDONOUS PLANTS. 417 of the Old World, from which the poisonous Laurel-water and the virulent Oil of Laurel are obtained. Our Southern species, Prunus (Laurocerasus) Caroliniana, poisons cattle which eat its foliage. The root of Gillenia (Bowman’s Root, Indian Physic) is emetic in large doses, in small doses it acts as a tonic. The bark and root in all are astringent. The bark of Amygdaleae also exudes gum. That of the Wild Black Cherry is febrifugal; and the timber is useful in cabinet-work. Sweet and bitter almonds are the seeds of varieties of Amygdalus communis: the oil of the former resembles olive-oil; that of the latter is poisonous. Of the Peach, Apricot, Nectarine, Plum, and Cherry, it is unnecessary to speak. The strawberry, raspberry, and blackberry are the principal fruits of the proper Rosacete. The leaves of Rosa centifolia are more commonly distilled for Rose-water: and Altar of Roses is obtained from R. Damascena, &c. — Pomaceous fruits, such as the apple, pear, quince, services, medlar, &c., yield to none in importance : their acid is usually the malic. 815 816 818 817 814 821 819 815. Ord. Calycanthaceae. A small group of shrubs, between the FIG. 814. Flowers of Calycanthus floridus. 815. Vertical section of a flower, showing the hollow receptacle, &c.; the floral envelopes cut away. 816. A stamen, seen from, without. 817. A pistil. 818. Section of the ovary, showing the two ascending ovules. 819. The closed pod-shaped receptacle in fruit. 820. A vertical section of an achenium, showing the embryo of the seed. 821. Cross-section of an embryo, showing the strongly convolute cotyledons.418 ILLUSTRATIONS OF THE NATURAL ORDERS. last order and the next, distinguished from Rosacea; by their oppo- site leaves without stipules, and their convolute cotyledons : the ovaries are enclosed in a fleshy calyx-tube as in a rose-hip. — It comprises only two genera; viz. Calycanthus (Carolina Allspice, Sweet-scented Shrub, &c.), and Chimonanthus, of Japan. They are cultivated for their fragrant flowers The bark and foliage exhale a slight camphoric odor; and the flowers give a fragrance like that of strawberries. 81G. Orel. MyrtaCCSC (Myrtle Family). Aromatic trees or shrubs, with opposite and simple entire leaves, which are punctate with pellucid dots, and often furnished with a vein running parallel with and close to the margin, without stipules ; the calyx-tube adherent to the ovary; many stamens; and seeds without albumen. — Fx. Myrtus, the Myrtle, is the most familiar representative of this beautiful tropical and subtropical order. The species abound in a pungent and aromatic volatile oil, and an astringent principle. Cloves are the dried flower-buds of C'aryophyllus aromaticus. Pi- mento (Allspice) is the dried fruit of Eugenia Pimenta. Cajeput oil, a powerful sudorific, is distilled from the leaves and fruit of a Melaleuca of the Moluccas. Australian species of Eucalyptus yield a large quantity^ of tannin. The aromatic fruits of many species, filled with sugar and mucilage, and acidulated with a free acid, are highly prized; such, for instance, as the Pomegranate, the Guava, Rose-Apple, &e. 817. Ord. lelastomacea:. Trees, shrubs, or herbs, with opposite ribbed leaves, and showy flowers, with as many or twice as many stamens as petals ; the anthers mostly appendaged and opening by pores, indexed in aestivation : further distinguished from Myrtuceas by the leaves not being dotted; and from Lythraeese by the adna- tion of the calyx-tube (by its nerves at least) with the ovary.—Ex. The beautiful species of Rhexia represent this otherwise tropical order in the United States. The berries of Melastoma are eatable, and tinge the lips black (like whortleberries) ; whence the generic name. 818. Onl. lythraeese (Loosestrife Family) is distinguished among these perigynous orders, with exalbuminous seeds, by its tubular calyx enclosing the two —four-celled ovary, but entirely free from it. The styles are perfectly united into one: the fruit is a thin capsule. The stamens are inserted on the tube of the calyx below the petals. — Ex. Lythrum. Chiefly tropical, of little economical use.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 419 819. Ord. Rhizophoraeeee (Mangrove Family) consists of a few tropical trees (extending into Florida and Louisiana), growing in maritime swamps, where they root in the mud, and form thickets on the verge of the ocean. The ovary is often partly free from the calyx, two-celled, with two pendulous ovules in each cell. These plants are remarkable for their opposite leaves, with interpetiolar stipules, and for the germination of the embryo while within the pericarp.— Ex. Rhizopliora, the Mangrove (Fig. 141). The as- tringent bark has been used as a febrifuge, and for tanning. 820. Ord. Combrelaccte consists of tropical trees or shrubs (which have one or two representatives in Southern Florida), often apeta- lous, but with slender colored stamens ; distinguishable from any of the preceding orders of this group by their one-celled ovary, with several suspended ovules, but only a solitary seed, and convolute cotyledons. — Ex. Combretum. 821. Ord. Onagraccae {Evening-Primrose Family). Herbs, or rare- ly shrubby plants, with alternate or opposite leaves, not dotted nor furnished with stipules. Flowers usually tetramerous. Calyx ad- herent to the ovary, and usually produced beyond it into a tube. FIG. 822. Flower of (Enothera fruticosa. 823. The same, with the petals removed. 824. Magnified grains of pollen, with some of the intermixed cellular threads. 825. Cross-section of the four-lobed and four-celled capsule. FIG. 826. Hippuris vulgaris (suborder Haloragese). 827. Magnified flower, with the sub- tending leaf. 828. Vertical section of the ovary. 829. Vertical section of the fruit and seed.420 ILLUSTRATIONS OF THE NATURAL ORDERS. Petals usually four (rarely three or six, occasionally absent), and the stamens as many, or twice as many, inserted into the throat of the calyx. Ovary commonly four-celled : styles united. Fruit mostly capsular. — Ex. Chiefly an American order ; many are ornamental in cultivation. Fuchsia, remarkable for its colored calyx and ber- ried fruit; CEnothera (Evening Primrose) ; Epilobium, where the seeds bear a coma; Ludwigia, which is sometimes apetalous ; and Circica, where the lobes of the calyx, petals, stamens, cells of the ovary, and the seeds, are reduced to two; showing a connection with the appended 822. Subot'tl. Haloragete, which are a sort of reduced aquatic Ona- gracece, often apetalous: the solitary seeds commonly furnished with albumen.—Ex. Myriophyllum (Water-Milfoil) and Hippuris (Horse- tail), where the limb of the calyx is almost wanting; the petals none; the stamens reduced to a single one, and the ovary to a single cell, with a solitary seed. 837 836 830 823. Ord. Grossulacca; ( Gooseberry Family ). Small shrubs, either spiny or prickly, or unarmed; with alternate, palmately lobed and FIG. 830. The cultivated Gooseberry 5 a branch in flower. 831. Branch in fruit 832 The calyx, bearing the petals and stamens, cut away from the summit of the ovary (833), and laid open. 83-1, 835. Sections of the unripe fruit. 836. Magnified seed, with a conspicuous rhaphe. 837. Longitudinal section of the same, showing the minute embryo at the extrem- ity of the albumen.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 421 veined leaves, usually in fascicles, often sprinkled with resinous dots. Flowers in racemes or small clusters. Calyx-tube adherent to the one-celled ovary, and more or less produced beyond it, five-lobed, sometimes colored. Petals (small) and stamens five, inserted on the calyx. Ovary with two parietal placentas: styles more or less united. Fruit a many-seeded berry. Embryo minute, in hard albumen. — Ex. Ribes (Gooseberry and Currant). Never unwhole- some : the fruit usually esculent, containing a mucilaginous and sac- charine pulp, with more or less malic or citric acid. Two or three red-flowered species of Oregon and California, and the Yellow or Missouri Currant, are ornamental in cultivation. 824. Ol‘d. Cactaccac (Cactus Family). Succulent shrubby plants, peculiar in habit, with spinous buds, usually leafless: the stems either globular and many- angled, columnar with several angles, or flattened and joint- ed. Flowers usually large and showy. Calyx of sev- eral or numerous sepals, im- bricated, coherent with and crowning the one-celled ova- ry, or covering its whole sur- face ; the inner usually con- founded with the indefinite petals. Stamens indefinite, with long filaments, cohering with the base of the petals. Styles united: stigmas and parietal placentae several. Fruit a berry. Seeds numerous, with a curved or fleshy and rounded em- bryo, and little or no albumen. — All American, the greater part Mexican or on the borders of Mexico. The common Opuntia (Prickly Pear) extends north to New England : its mucilaginous fruit is eatable. So is the sweet red pulp of the huge Cereus gigan- teus of Sonora and South California, which forms a singular tree, forty or fifty feet high. Cereus grandiflorus is the magnificent Night-blooming Cereus. 825. Ord. Loasace®. Herbs usually clothed with rigid or stinging hairs; leaves opposite or alternate, without stipules; the flowers showy. Calyx-tube adherent to the one-celled ovary; the limb FIG. 838. Flower of Mamillaria csespitosa, of the Upper Missouri. 36422 ILLUSTRATIONS OF THE NATURAL ORDERS. mostly five-parted. Petals as many, or twice as many, as the lobes of the calyx. Stamens perigynous, indefinite, and in several parcels, or sometimes definite. Style single. Ovary with three to five parietal placentie. Seeds few or numerous, albuminous. — Ex. Lo- asa, Mentzelia, Cevallia; the latter with solitary seeds and no albu- men. All American, and in the United States nearly confined to the regions beyond the Mississippi- The bristles of Loasa sting like nettles. 826. Ol'd. TurncracctE. Herbs, with the habit of Cistus or IToli- anthemum; the alternate leaves without stipules. Flowers solitary, showy. Calyx five-lobed ; the five petals and five stamens inserted on its throat. Ovary free from the calyx, one-eelled, with three parietal placentie. Styles distinct, commonly branched or many- cleft at the summit. Fruit a three-valved capsule. Seeds numer- ous (anatropous), with a crustaceous and reticulated testa, and a membranaceous aril on one side. Embryo in fleshy albumen.—Ex. Turnera, of which there is one species in Georgia. 827. Ol’d. Passifloi'UCPEE (Passion-jloiver Family). Herbs, or somewhat shrubby plants, climbing by tendrils; with alternate, entire, or palmately-lobed leaves, mostly with stipules. Flowers often showy. Calyx mostly of five sepals, united below, free from the one-celled ovary ; the throat bearing five petals and a filament- ous crown. Stamens as many as the sepals, monadelphous, and ad- hering .to the stalk of the ovary, which has usually three club-shaped styles or stigmas, and as many parietal placentte. Fruit fleshy or berry-like. Seeds numerous, with a brittle sculptured testa, enclosed in pulp. Embryo enclosed in a thin albumen. — Ex. Passiflora (the Passion-flower, Gratiadllla) : nearly all natives of tropical America. Two species are found as far north as Virginia and Ohio. Many are cultivated for their singular and showy flowers. The acidulous refrigerant pulp of Passiflora quadrangularis (the Granadilla), P. edulis, and others, is eaten in the "West Indies, &c. But the roots are emetic, narcotic, and poisonous. 828. Ol'd. PapayacetE comprises merely a small genus of tropical dioecious trees, of peculiar character: the principal one is the Pa- paw-tree (Carica Papaya) of tropical America, which has been in- troduced into East Florida. The fruit, when cooked, is eatable ; but the juice of the unripe fruit, as well as of other parts of the plant, is a powerful vermifuge. The juice contains so much fibrine that it has an extraordinary resemblance to animal matter: meat washedEXOGENOUS OR DICOTYLEDONOUS PLANTS. 423 in water impregnated with this juice is rendered tender: even the exhalations from the tree are said to produce the same effect upon meat suspended among the leaves. 829. Ord. Cucurbitacea? (Gourd Family). Tender or succulent herbs, climbing by tendrils; with alternate, palmately veined or lobed, rough leaves, and monoecious or dioecious flowers. Calyx of four or five (rarely six) sepals, united into a tube, and in the fertile flowers adherent to the ovary. Petals as many as the sepals, com- monly more or less united into a monopetalous corolla, which co- heres with the calyx. Stamens five or three, or rather two and a half, i. e. two with two-celled anthers, and one with a one-celled an- ther, inserted into the base of the corolla or calyx, either distinct or variously united by their filaments, and long, sinuous or contorted anthers (Fig. 4G5-467). Ovary one- to five-celled ; the thick and fleshy placentas often filling the cells, or diverging before or after reaching the axis, and carried back so as to reach the walls of the pericarp, sometimes manifestly parietal; the dissepiments often dis- appearing during its growth, sometimes only one-ovuled from the top : stigmas thick, dilated or fringed. Fruit (pepo, Fig. 5 GO) usually fleshy, with a hard rind, sometimes membranous. Seeds mostly flat, with no albumen. Embryo straight: cotyledons foliaceous. — Ex. The Pumpkin and Squash (Cucurbita), Gourd, Cucumber, and./' Melon. When the acrid principle which prevails throughout the order is greatly diffused, the fruits are eatable, and sometimes deli- cious : when concentrated, as in the Bottle Gourd, Bryony, &c., they are dangerous or actively poisonous. The officinal Colocynth, the resinoid and bitter pulp of the fruit of Cucumis Colocynthis, is very acrid and poisonous ; and Flaterium, obtained from the juice of the Squirting Cucumber, is still more violent in its effects. The seeds of all are harmless. 830. Ord. Crassulacea; (Stonecrop Family). Herbs, or slightly shrubby plants, mostly fleshy or succulent; remarkable for the»com- plete symmetry and regularity of their flowers (449, Fig. 359 - 3G5). Calyx of three to twenty sepals, more or less united at the base, free from the ovaries, persistent. Petals as many as the sepals, rarely combined into a monopetalous corolla. Stamens as many or twice as many as the sepals, more or less perigynous. Pistils always as many as the sepals, distinct, or rarely (in Pentliorum and Dia- morpha) partly united: ovaries becoming follicles in fruit, several- seeded. Embryo straight, in thin albumen. — Ex. Sedum (Stone-424 ILLUSTRATIONS OF THE NATURAL ORDERS. crop, Orpine, Live-for-ever), Crassula, Sempervivum (Ilouseleek), &c. Tlie)r mostly grow in arid places, and are of no economical im- portance. 831. Old. SaxifragaCCEC (Saxifrage Family). Herbs or shrubs, with alternate or opposite leaves. Calyx of four or five more or less united sepals, either free from or more or less adherent to the ovary, persistent. Petals as many as the sepals, rarely want- ing. Stamens as many, or commonly twice as many, as the pistils or sepals, or rarely indefinitely numerous, perigynous. Ovaries mostly two (sometimes three or four), usually united below and distinct above, sometimes completely united and even the styles also. Seeds numerous, with a straight embryo in fle.slijr albumen. The order, taken in the largest sense, includes four tribes, as they should probably be called, rather than suborders, which some botanists regard even as distinct orders, viz.: The Saxifrages, or true Saxifrage Family, which are herbs, with no manifest stipules, except the wings or appendages at the base of the petiole or radical leaves. Ex. Sax- FIG. 839. Sullivantia Ohionia. 840. Flower with the calyx laid open, somewhat enlarged. 841. Fruit surrounded by the persistent calyx and withered petals, enlarged. 842. Section of the lower part of the capsule, magnified ; showing the central placenta covered with the as- cending seeds. 843. A magnified seed, with its cellular, wing-like testa. 844. Section of the nucleus, showing the embryo in the midst of albumen.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 425 ifraga, Mitella, &c. Roots somewhat astringent, in Ileuchera so much so that H. Americana is called Alum-root. Hyduangieje : shrubs, with simple opposite leaves and no stipules. Ex. Hydrangea and Philadelphus, the latter polyandrous. Bauere^s : Australian shrubs, with opposite and compound sessile leaves and no stipules. Cunonie.® : woody plants, with opposite simple or compound leaves and interpetiolar stipules. Escallonie.e : woody plants, with alternate simple leaves and no stipules. Ex. Escallonia, of South America, Itea. 832. Ord. Ilamamelaccae ( Witch-Hazel Family). Shrubs or small trees, with alternate simple leaves, without stipules. Flowers often polygamous. Petals valvate in aestivation. Stamens twice as many as the petals, half of them sterile ; or numerous, and the petals none. Summit of the two-celled ovary free from the calyx, a single ovule suspended from the summit of each cell: styles two, distinct. Cap- sule cartilaginous or bony. Seeds bony, with a small embryo in hard albumen. — Ex. Hamamelis (Witch-Hazel), Fothergilla. A small order, of little importance. Hamamelis is remarkable for flowering late in autumn, just as its leaves are falling, and perfecting its fruit the following spring. To this order is now appended the genus Liquidambar, or Sweet-Gum, which has been taken as the type of a distinct order ; but it is rather a reduced and apetalous form of the present order. It may stand as a suborder, viz. 833. Subord. Balsamifluic {Sweet-Gum Family), consisting of a few trees, with alternate palmately-lobed leaves, and deciduous stipules ; the monoecious flowers in rounded aments or heads, desti- tute of floral envelopes ; the indurated capsules forming a head: they are two-beaked, opening between the beaks, the cells ripening one or two seeds, although the ovules are numerous. The Sweet-gum is so called from a fragrant balsam or storax which it exudes. 834. Ord. Uinbelliferte {Parsley Family). Herbs, with hollow stems, and alternate, dissected leaves, with the petioles sheathing or dilated at the base. Flowers in simple or mostly compound um- bels, which are occasionally contracted into a kind of head. Calyx entirely coherent with the surface of the dicarpellary ovary; its limb reduced to a mere border, or to five small teeth. Petals five, valvate in aestivation, inserted, with the five stamens, on a disk which crowns the ovary; their points indexed. Styles two; their bases often united and thickened, forming a stylopodium. Fruit dry, a cremocarp, consisting of two united carpels, at maturity sepa- 30*426 ILLUSTRATIONS OF THE NATURAL ORDERS. rable from each other, and often from a slender axis (carpophore), into two achenia, or mericarps: the face by which these cohere re- ceives the technical name of commissure: they are marked with a definite number of ribs (juga), which are 'sometimes produced into wings: the intervening spaces (intervals), as well as the commissure, sometimes contain canals or receptacles of volatile oil, called vittce: these are the principal terms peculiarly employed in describing the plants of this difficult family. Embryo minute. Albumen hard or corneous. — Ex. The Carrot, Parsnip, Celery, Caraway, Anise, 848 847 846 Coriander, Poison Hemlock, &c. are common representatives of this well-known family. Nearly all Umbelliferous plants are furnished with a volatile oil or balsam, chiefly accumulated in the roots and in the reservoirs of the fruit, upon which their aromatic and carmina- tive properties depend: sometimes it is small in quantity, so as merely to flavor the saccharine roots, which are used for food ; as in the Carrot and Parsnip. But in many an alkaloid principle exists, pervading the foliage, stems, and roots, especially the latter, which ren- FIG. 845. Conium maculatum (Poison Hemlock), a portion of the spotted stem, -with a leaf; and an umbel with young fruit. 846. A flowering umbellet. 847. A flower, enlarged. 848. The fruit. 849. Cross-section of the same, showing the involute (catnpylospermoits) albumen of the two seeds. 850. Longitudinal section of one wericarp, exhibiting the minute embryo near the apex of the albumen.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 427 ders them acrid-narcotic poisons. And, finally, many species of warm regions yield odorous gum-resins (such as Galbanum, Assa- foetida, &c.), which have active stimulant properties. The stems of Celery (Apium graveolens), which are acrid and poisonous when the plant, grows wild in marshes, &c., are rendered innocent by cultivation in dry ground, and by blanching. Among the virulent acrid-narcotic species, the most famous are the Hemlock (Conium maculatum), and Cicuta maculata (Cowbane, Water-Hemlock), indi- genous to this country, the root of which (like that of the C. virosa of Europe) is a deadly poison. A drachm of the fresh root has killed a boy in less than two hours. 835. Ortl. Araliace* ( Ginseng or Ivy Family) scarcely differs from the last in floral structure, except that the ovary is mostly composed of more than two carpels, and these do not separate when ripe, but FIG. 851. Flower of Osmorrhiza longistylis. 852. Umbel of the same in fruit: a, the invo- lucels. 853. The ripe mericarps separating from the axis or carpophore. 854. Cross-section of the fruit of Angelica, where the lateral ribs are produced into wings : the black dots repre- sent the vittae, as they appear in a cross-section. 855. One of the mericarps of the same, show- ing the inner face, or commissure, as well as the transverse section, with two of the vittae, a. FIG. 856. Flower of Aralia nudicaulis (Wild Sarsaparilla); a vertical section, displaying two of the cells of the ovary. 857. Cross-section of the ovary. 858. Longitudinal section of a 6eed, magnified, showing the small embryo at the upper end.428 ILLUSTRATIONS OF THE NATURAL ORDERS. become drupes or berries ; and the albumen is not hard like horn, but only fleshy. — Ex. Aralia (the Spikenard, the Wild Sarsaparilla, Ginseng), and Hedera (the Ivy). Their properties are aromatic, stimulant, somewhat tonic, and alterative. 836. Ofd. Cornacets ( Cornel or Dogwood Family). Chiefly trees or shrubs; with the leaves almost always opposite, destitute of stipules. Flowers in cymes, sometimes in heads surrounded by colored involu- cres. Calyx coherent 110111 the two-celled ovary; the very small limb four-toothed. Petals four, valvate in {estivation. Stamens four, alternate with the petals. Styles united into one. Fruit a two-celled drupe. Embryo nearly as long as the albumen ; cotyle- dons broad and flat. — Ex. Cornus, the Dogwood. Chiefly remark- able for their bitter and astringent bark, which in this country has been substituted for Cinchona. The peculiar principle they contain is named Comine. Cornus Canadensis (Fig. 321, 322) is a low and herbaceous species. — A reduced form of this order occurs in Nyssa (the Tupelo or Sour-Gum), which has dioecious or polyga- mous flowers, the sterile ones at least apetalous, the fertile ones ap- pearing to be so on account of the limb of the adherent calyx being obsolete ; the style stigmatic down one side and revolute ; the ovary and drupe one-celled and one-seeded. The fruit is acid. The wood of the common Sour or Black Gum-tree, or Peperidge, is close- grained, and hard to split. Division II. Monopetalous Exogenous Plants. Floral envelopes consisting of both calyx and corolla: the petals more or less united (corolla gamopetalous). — A few true Ericacem, with all the Pyrolete and some Monotropem, are polypetalous : the Aquifoliacem are nearly so, as are some of several of the succeeding orders, and Fraxinus, &c. in Oleacece. The latter genus is apeta- lous, and so are one or two genera in other generally Monopetalous orders. Conspectus of the Orders. Group 1. Ovary coherent with the calyx, two- to scveral-celled, with one or many ovules in each cell. Seeds albuminous, with a small embryo. Sta- mens inserted on the corolla. Leaves opposite. Stipules wanting. Caprifoliace.’e. Stipules interpetiolar (or in one group the leaves whorled). Rubiacea;.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 429 Group 2. Ovary coherent with the calyx, one-cclled and one-ovulcd, or rarely 3-cclled with two of the cells empty, and the third one-ovuled. Seed with little or no albumen. Stamens inserted on the corolla. Limb of the ca- lyx mere ring, crown, or pappus, or none. Stipules none. Stamens distinct. Seed suspended. Leaves opposite. Stamens 3, or rarely 2. Flowers often irregular. Valerianacea:. Stamens 4. Flowers regular, in an involucrate head. Dips ace a:. Stamens syngenesious. Seed erect. Composite. Group 3. Ovary coherent with the calyx, with two or more cells and numer- ous ovules. Seeds albuminous. Stamens inserted with the corolla (epi- gynous) : anthers not opening by pores. Juice more or less milky. Corolla irregular. Stamens united by their anthers or filaments. LobeliacejE. Corolla regular. Stamens distinct. Campanulaceje. Group 4. Ovary free from the calyx, or sometimes coherent with it, with two or more cells and few or many ovules. Seeds albuminous. Stamens in- serted with the corolla, or rarely somewhat coherent with its base, as many, or twice as many, as its lobes : anthers mostly opening by pores or chinks. Ericaceae. Group 5. Ovary free, or rarely coherent with the calyx, several-celled, with a single ovule (or at least a single seed) in each cell. Seeds mostly albu- minous. Stamens definite, as many as the lobes of the (often almost poly- petalous) corolla and alternate with them, or two to four times as many : anthers not opening by pores. — Trees or shrubs. Stamens as many as the lobes of the corolla: no sterile ones. Aquifoliace/g. Stamens more numerous than the lobes of the corolla, and all fertile. Flowers polygamous : calyx free. Ebenaceje. Flowers perfect: calyx more or less adnate. Styracaceje. Stamens as many fertile as the lobes of the corolla and opposite them. Sapotaceve. Group 6. Ovary free, or with the base merely coherent with the tube of the calyx, one-cclled, with a free central placenta. Stamens inserted into the regular corolla opposite its lobes ! which they equal in number. Seeds albuminous. Shrubs or trees (all tropical) : fruit drupaceous. Myrsinace/e. Herbs : fruit capsular. Primulace/E. Group 7. Ovary free, one-cellcd, with a single ovule; or two-celled with several ovules attached to a thick central placenta. Stamens as many as the lobes of the regular corolla or the nearly distinct petals. Seeds albu- minous. Ovary two-celled : style single : stamens 4, or rarely less. Plantaginace^e. Ovary onc-celled : styles and stamens 5. Plumbaginace^e. Group 8. Ovary free, or rarely partly coherent, one- or two- (or spuriously430 ILLUSTRATIONS OF THE NATURAL ORDERS. four-) celled, with numerous ovules. Corolla bilabiate or irregular; the stamens inserted upon its tube, and mostly fewer than its lobes. Ovary 1-celled with a central placenta. Stamens 2. LentibulacEyE. Ovary 1-celled, or spuriously 2- 5-celled with parietal placenta;. Seeds very numerous and minute, albuminous. Plants destitute of green herbage. OrobanciiaceyE. Plants with green herbage. GesneriaceyE. Seeds few or many, large : albumen none. Bignoniacea:. Ovary 2-eelled, with the placenta; in the axis. Corolla convolute in aestivation. Seeds few; no albumen. AcantiiacEyE. Corolla imbricated in aestivation. Seeds albuminous. ScrophulariacEyE. Group 9. Ovary free, two- to four-lobcd, or at least separating or splitting into as many one-seeded nuts or aehenia, or drupaceous. Corolla regular or irregular; the stamens inserted on its tube, equal in number or fewer than its lobes. Albumen little or none. Stamens 4, didynamous, or 2. Corolla more or less irregular. Ovary not 4-lobed : style terminal. VerbenaceyE. Ovary of 4 lobes around the base of the style. LabiatyE. Stamens 5. Flower regular. Leaves alternate. Borp.aginaceas. Group 10. Ovary free, compound, or rarely the carpels two or more and dis- tinct : the ovules usually several or numerous. Corolla regular; the sta- mens inserted upon its tube, as many as the lobes and alternate with them. Seeds albuminous. Placentse 2, parietal (sometimes expanded or united). Embryo minute. Hairy herbs. Albumen cartilaginous. II ydropiiyllaceas. Smooth herbs. Albumen fleshy. Gentianaceas. Placenta; in the axis : ovary with 2, 3, or rarely several cells. Embryo large, coiled or folded. Seeds few. ConvolvulacEyE. Embryo straight, with broad cotyledons. PolemoniaceyE. Embryo curved, rarely straight, slender. Seeds numerous. SolanaceyE. Group 11. Ovaries 2 and distinct (or sometimes united), but the stigmas united into one and often the styles also. Stamens as many as and alternate with the lobes of the regular corolla, which is convolute, or rarely valvate in aestivation. Anthers often connected with the stigma. Fruit usually a pair of follicles. Seeds mostly numerous, often comose. Embryo large and straight, in sparing albumen. Juice milky. Pollen powdery. ApocynacEyE. Pollen in waxy or granular masses. Asclepiadaceas. Group 12. Ovary free, two celled, the cells mostly two-ovulcd, .and the fruit one- seeded. Corolla regular (sometimes nearly polypetalous or wanting); the stamens (two) fewer than its lobes. — Shrubs or trees. Seeds erect. Corolla imbricated or contorted in activation. JasminyVCEyE. Seeds suspended. Corolla valvate in activation. OleaceyE.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 431 837. Ord. Caprifoliacc® (Honeysuckle Family). Mostly shrubs, often twining, with opposite leaves, and no stipules (but Viburnum often has appendages like them). Calyx-tube adnate to the 2-5- celled ovary; the limb 4 - 5-cleft. Corolla regular or irregular. Stamens inserted on the corolla, as many as the petals of which it is composed, and alternate with them, or rarely one fewer. Fruit mostly a berry or drupe. Seeds pendulous, albuminous. — Ex. The Honeysuckles (Lonicera), which have usually a peculiar bilabiate corolla (473), the Snowberry (Symphoricarpus), Diervilla, which has a capsular fruit, &c., compose the tribe Lonicere.e, character- ized by their tubular flowers and filiform style: while the Elder (Sambucus) and Viburnum, which have a rotate or urn-shaped corolla, form the tribe Sayibuceae. Chiefly plants of temperate regions. Several species, such as Honeysuckle, &c., are widely cultivated for ornament. They are generally bitter, and rather active or nauseous in their properties. 838. Ord, Rubiacetc (Madder Family). Shrubs or trees, or often herbs, with the entire leaves either in whorls, or opposite and fur- nished with stipules. Calyx-tube completely, or rarely incompletely FIG. 859. Branch of Lonicera (Xylosteon) oblongifolia: the two ovaries united! 860. Lo- nicera (Caprifolium) parviflora. 861. A flower about the natural size. 862. Longitudinal sec- tion of the ovary. 863. Longitudinal section of a magnified seed, showing the albumen and minute embryo.432 ILLUSTRATIONS OF THE NATURAL ORDERS. adnate to the 2-5-celled ovary; the limb four- or five-cleft or toothed, or occasionally obsolete. Stamens as many as the lobes of the regular corolla, and alternate with them, inserted on the tube. Fruit various. Seeds albuminous. — This extensive family divides into two principal suborders, viz.: — 839. Suboril. Stellate® (Madder Family proper). Herbs, whh the leaves in whorls ; but all except a single pair are generally supposed to take the place of stipules. — Ex. Galium, Rubia (the Madder), &c., nearly all belonging to the colder parts of the world. The roots of Madder yield the important dye of that name; and those of several species of Galium are imbued with a similar red coloring- matter. 840. Sllbord. Cinclionc® (Peruvian-Barh Family). Shrubs, trees, or herbs; the leaves opposite and furnished with stipules, which are very various in form and appearance. — Ex. Ceplialanthus (Button- brush), Pinkneya, and an immense number of tropical genera. Very active, and generally febrifugal properties prevail in this large order. It furnishes some of the most valuable known remedial agents, among them Peruvian Bark or Cinchona, and Ipecacuanha. FIG. 864. Piece of Rubia tinctoria (the Madder) in flower. 865. The fruit. 866 The two constituent portions of the fruit separating. 867 Vertical section of one carpel, showing the curved embryo. 868. Section of a flower of Galium. FIG. 869. Cephalanthus occidentalis, the Button-Bush. 870. A flower, taken from the head. 871. The corolla laid open. 867 868 871 870EXOGENOUS OR DICOTYLEDONOUS PLANTS. 433' The febrifugal properties of the former depend on the presence of two alkaloids, Cinchonia and Quinia, both combined with Kinic acid. The Quinquina barks, which are derived from some species of Ex- ostemma and other West Indian, Mexican, and Brazilian genera, contain neither cinchonia nor quinia. The bark of Pinckneya pu- bens, of the Southern United States, has been substituted for Cin- chona. — The true Ipecacuanha is furnished by the roots of Cepha- ;elis Ipecacuanha of Brazil and New Granada. Its emetic principle (called Emetine) also exists in Psychotria emetica of New Granada, which furnishes the striated, black, or Peruvian Ipecacuanha. The order likewise furnishes Coffee, the horny seed (albumen) of Coffaea Arabica. According to Blume, the leaves of the Coffee-plant are used as a substitute for tea in Java. — To this order may be ap- pended, either as a suborder, or, as in a general work it is more con- veniently regarded, the 880 874 841. Ord. Logailiaccte, which may be briefly said to be Rubiacese with a free calyx, and manifestly connected with the Cinchoneae through the Houstonia section of Oldenlandia, with a partly free FIG. 872. Oldenlandia (Houstonia) casrulea. 873, 874 The two sorts of flowers that differ- ent individuals bear, with the corolla laid open ; one with the stamens at the base, the other at the summit of the tube : the lower figure shows also a section of the ovary. 875. Cross- section of an anther, magnified. 876 Anther less enlarged, opening longitudinally. 877. Capsule with the calyx. 878, 879. Views of the capsule in dehiscence. 880. Diagram of a cross-section of the unexpanded flower. 37434 ILLUSTRATIONS OP THE NATURAL ORDERS. calyx. On the other hand, they run close to Scrophulariaeea? and Apocynacea;.— Spigelia Marilandica (the Carolina Pink-root, a well known vermifuge, of somewhat acrid-narcotic properties), and Gelsemium (the so-called Yellow Jessamine of the Southern States) are the most conspicuous representatives of the group in this coun- try. The active properties of the family are most conspicuous in species of Strychnos. The fatal drug, Nux-vomica, from which strychnine is extracted, consists of the seeds of an East Indian Strychnos. Tieute, another frightful poison, is prepared from a Java species, and the Ouari poison of South America, from a third species. Meanwhile a Brazilian species, S. Pseudoquina, has a harm- less fruit, and its bark (Copalche bark) is reputed to be an excellent febrifuge, fully equal to Cinchona. 842. Ord. Valerianate® ( Valerian Family). Herbs with opposite leaves, and no stipules. Flowers often in cymes, panicles, or heads. Limb of the adnate calyx two- to four-toothed, obsolete, or else forming a kind of pappus. Corolla tubular or funnel-form, some- times with a spur at the base, four- or live-lobed. Stamens distinct, inserted on the corolla, usually fewer than its lobes. Ovary one- FIG. 881. Branch of Fedia Fagopyrum. 882. A magnified flower. 883. A fruit. 884. An enlarged cross-section of the same, and the cotyledons of the seed in the single fertile cell: the two empty cells are confluent into one. 885 Flower of a Valerian, with one of the pappus- like bristles of the calyx unrolled. 886. Section through the ovary and embryo ; the bristles of the calyx broken away.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 435 ovuled, with one perfect cell and two abortive ones. Fruit a kind of achenium. Seed suspended, cxalbuminous. Embryo straight, radicle superior.—Ex. Valeriana, the Valerian, and Fedia, the Lamb- Lettuce : the latter is eaten as a salad. The perennial species, especially the roots, exhale a heavy and peculiar odor, have a some- what bitter, acrid taste, and are antispasmodic and vermifugal. Valerian of the shops is chiefly from Valeriana officinalis of the South of Europe. It produces a peculiar intoxication in cats. The large roots of V. edulis are eaten by the aborigines of Oregon. The famous Spikenard of the ancients, esteemed as a stimulant medicine as well as a perfume, is the root of a Nardostachys of the Himalayas. 843. Ol’d. Dipsacctc (Teasel Family). Herbs, with opposite or whorled sessile leaves, destitute of stipules. Flowers in dense heads, which are surrounded by an involucre. Limb of the adnate calyx cup-shaped and entire or toothed, or forming a bristly or plumose pappus. Corolla tubular ; the limb four- or five-lobed, some- what irregular. Stamens four, distinct, or rarely united in pairs, often unequal, inserted on the corolla. Ovary one-celled, one-ovuled. Seed suspended, albuminous. — Ex. Dipsacus, the Teasel, and Seabiosa, or Scabious. All natives of the Old World. Teasels are the dried heads of Dipsacus fullonum, covered with stiff and spiny bracts, with recurved points. 844. Onl. Composita) (Composite or Sunflower Family). Herbs or shrubs; with the flowers in heads (compound flowers of the older botanists, 394, Fig. 323-325), crowded on a receptacle, and surrounded by a set of bracts (scales) forming an involucre ; the sep- arate flowers often furnished with bractlets (chaff, palece). Limb of the adnate calyx obsolete, or a. pappus (Fig. 569-573), consisting FIG. 887. A head of flowers of Cichory (Fig. 323) vertically divided.436 ILLUSTRATIONS OF THE NATURAL ORDERS. of hairs, bristles, scales, &c. Corolla regular or irregular. Sta- mens five, as many as the lobes or teeth of the regular corolla, in- serted on its tube : anthers united into a tube (syngenesious, Fig. 463, 464). Style two-cleft. Ovule solitary, erect, anatropous. Fruit an aehenium (Fig. 568-573), either naked or crowned with a pappus. Seed destitute of albumenn. Embryo straight. — This vast but very natural family is divided into three series or suborders ; viz.: — 845. Subord. Tubuli flortE. Corolla tubular and regularly four- or five-lobed, either in all the flowers (when the head is discoid), or in the central ones (those of the disk) only, the marginal or ray flowers presenting a ligulate or strap-shaped corolla. — Ex. Liatris, Eupato- rium, &c.; where the heads are liomogamous, that is, the flowers all tubular, similar and perfect: Helianthus (Sunflower), Helenium, Aster, &e.; where the heads are lieterogamous ; the disk jlowers being tubular and perfect, while those of the ray are ligulate, and either pistillate only, or neutral, that is, destitute of both stamens and pistils. 846. Subord. Labiatiflortc. Corolla of the disk-flowers bilabiate.— Ex. Chaptalia, of the Southern United States; and many South American genera, &c. 847. SubOl'd. Liguliflora. Corolla of the flowers (both of the disk and ray) all ligulate and perfect. — Ex. The Dandelion, Lettuce, Cieliory (Fig. 887), &c. 848. This vast family comprises about a tenth part of all Phas- nogamous plants. A bitter and astringent principle pervades the whole order ; which in some is tonic (as in the Chamomile, the Boneset or Thoroughwort, &c.) ; in others, combined with mucilage, so that they are demulcent as well as tonic (Elecampane and Colts- foot) ; in many, aromatic and extremely bitter (such as Wormwood and all the species of Artemisia) ; sometimes accompanied by acrid qualities, as in the Tansy and the Mayweed, the bruised fresh herb- age of which blisters the skin. The species of Liatris, which abound in terebintliinc juice, are among the reputed remedies for the bites of serpents; so are some species of Mikania in Central America. The juice of Silphium and of some Sunflowers is resinous. The leaves of Solidago odora, which owe their pleasant amsate fragrance to a peculiar volatile oil, are infused as a substitute for tea. From the seeds of Sunflower, and several other plants of the order, a bland oil is expressed. The tubers of Ilelianthus tuberosus are eatenEXOGENOUS OK DICOTYLEDONOUS PLANTS. 437 under the name of Jerusalem artichokes ; Girasola, the Italian name of Sunflower, having become Anglicized into Jerusalem. True arti- chokes are the fleshy receptacle and imbricated scales of Cynara Scolymus. The flowers of Carthamus tinctorius, often called Saf- fron, yield a yellow dye, much inferior in quality to true Saffron. — The Liguliflor®, or Cichoraceae, all have a milky juice, which is narcotic, and has been employed as a substitute for opium. The bland young leaves of the garden Lettuce are a common salad. The 891 892 893 894 89S 888 889 890 897 898 roasted roots of the Wild Succory (Cichorium Intybus) are ex- FIG. 888. Head of Liatris squarrosa (discoid; the flowers all tubular and perfect). 889. The same, with the scales of one side of the imbricated involucre removed; and also all the flowers but one, showing the naked flat receptacle. 890. Portion of one of the plumose bris- tles of the capillary pappus 891 Head of Helenium autumnale (heterogamous), the rays neutral, consisting merely of a ligulate corolla. 892. The same, with the flowers all removed from the roundish receptacle, except a single disk-flower and one or two rays: the reflexed scales of the involucre in a single series. 893. Magnified disk-flower of the same : the corolla exhibiting the peculiar venation of the family ; namely, the veins corresponding to the sinuses, and sending a branch along the margins of the lobes. 894. The same, with the corolla re- moved ; the achenium crowned with the limb of the calyx in the form of a chaffy pappus, of about five scales. 895. A chaff of the pappus more magnified. 896 A tubular corolla of this family laid open, showing the venation; and also the five syngenesious anthers united in a tube, through which the two-cleft style passes. 897. Head of Dracopis amplexicaulis, with the flowers removed from the elongated spike-like receptacle, except a few at the base : a, achenium of one of the disk-flowers magnified, partly enclosed by its bractlet (chaff or palea); the pappus obsolete 898- Part of the involucre and alveolate (honeycomb-like) re- ceptacle of Onopordon or Cotton-Thistle. 899. A perfect and ligulate flower of the Dandelion, with its hair-like or capillary pappus. 37 *438 ILLUSTRATIONS OF THE NATURAL ORDERS. tensively used to adulterate coffee: and the roots of some species of Tragopogon (Salsify, Oyster-plant) and Seorzonera are well- known esculents. 849. Ord. tobcIiaccEE (Lobelia Family). Herbs or somewhat shrubby plants, often yielding a milky juice, with alternate leaves and perfect flowers. Limb of the adnate calyx five-cleft. Corolla irregularly five-lobed, usually appearing bilabiate, cleft on one side nearly or quite to the base. Stamens 5, epigynous, coherent into a tube. Stigma fringed. Capsule one - several-celled, many-seeded. Seeds albuminous. — Ex. Lobelia. All narcotieo-acrid poisons. The well-known Lobelia inflata (Indian Tobacco) is one of the most powerful articles of the materia medica, and most dangerous in the hands of the reckless quacks who use it. — This order is only a form of the next, with irregular flowers. 850. Ord. Campanulacca; (Campanula Family). Herbs, like the last, but the juice less acrid, and the corolla regular, campanulate, usually five-lobed, withering. Stamens five, distinct. Style fur- FIG. 900. Campanula rotundifolia, much reduced in size. 901. Lobelia inflata, reduced in size. 902. A flower, enlarged. 903. The united filaments and anthers enclosing the style; the corolla and limb of the calyx cut away. 904. The stigma surrounded by a fringe. 905- Trans- verse section of a capsule. 903. Section of a magnified seed, showing the embryo.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 439 nished with collecting hairs. — Ex. Campanula (Bell-flower, Hare- bell). Plants of little known importance to man, except for or- nament. 851. Ord. Ericacc* {Heath Family). Shrubs, or small trees, rarely herbs. Flowers regular and symmetrical, or nearly so ; the petals sometimes distinct. Stamens mostly distinct, free from the corolla, as many or twice as many as its lobes, and inserted with it (either hypogynous or epigynous) : anthers often appendaged, commonly opening by terminal pores. Pollen compound (of four united grains) except in the last suborder. Styles and stigmas united into one. Ovary with two or more cells and usually numerous ovules, free, or in Vaceineas coherent with the calyx-tube. Seeds usually indefinite, albuminous. — Most botanists give the rank of orders to the following suborders. 807 852. Subord. Tacciniete ( Whortleberry Family). Ovary adnate to the tube of the calyx, becoming a berry or drupaceous. ■ Anthers two-celled ; the cells nearly distinct, mostly prolonged above into a tube. Shrubs, with scattered or alternate leaves, often evergreen. — Ex. Vaccinium (Bilberry, Blueberry, Cranberry) and Gaylussacia (Whortleberry or Huckleberry). 853. Sllbortl. El'icinete {True Heath Family). Ovary free from the calyx. Fruit capsular, sometimes baccate or 'drupaceous. Mostly shrubs. Leaves various, often evergreen. Petals rarely distinct. — Ex. Erica (Heath), Kalmia, Rhododendron, Gaultheria, Andromeda, &c. FIG. 907. Branch of Rhododendron Lapponicum. 908. Enlarged flower, with its pedicel and bracts. 909. A flower with the corolla removed, more enlarged. 910 The capsule of R. maxi- mum, opening by septicidal dehiscence ; the valves breaking away from the persistent axis, or columella.440 ILLUSTRATIONS OF THE NATURAL ORDERS. 854. Subord. Epacridecc (Epcicris Family). Shrubby plants of the Southern hemisphere, with the aspect and character of Heaths, but the anthers one-celled are not appendaged. 855. Subord. Pyroleae (Pyrola Family). Ovary free from the calyx. Petals distinct. Anthers two-celled. Fruit a capsule. Seeds with a very loose cellular testa. Mostly herbs. Leaves flat and broad, evergreen. — Ex. Pyrola, Chimaphila. 913 919 920 921 856. Subord. Monotropcae (Indian-Pipe Family). Ovary free from the calyx. Petals distinct or united. Anthers two-celled, or con- fluently one-celled. Pollen simple. Fruit a capsule Seeds with a loose or winged testa. Parasitic herbs, destitute of green color, FIG. 911. Gaultheria procutnbens (Checkerberry, &c.) 912. The enlarging calyx in the im- mature fruit. 913. Vertical section of the pulpy or bcrry-like calyx and the included capsule (the seeds removed from the placenta in one cell). 914. Horizontal section of the same, show- ing the five-celled capsule, with a placenta proceeding from the inner angle of each cell. 915. Section of a seed, magnified. 916. Flower of a Yaccinium (Blueberry). 917. Vertical sec- tion of the ovary and adherent calyx 918. Anther of Vaccinium Vitis-Tdaea ; each cell pro- longed into a tube, aud opening by a terminal pore. 919. Anther of Vaccinium Myrtillus; the connectivum furnished with two appendages. 920. Stamen of an Andromeda (Cassiope), show- ing the appendages of the connectivum. 921. Stamen of Arctostaphylos TJva-Ursi, showing the separate anther-cells, opening by a terminal pore, the appendages of the connectivum, and the filament, which is swollen at the base.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 441 and with scales instead of leaves. — Ex. Monotropa, the Indian- Pipe and Pinesap. 857. In this diversified and widely diffused order, the bark and foliage are generally astringent, often stimulant or aromatic from a volatile oil or a resinous matter, and not seldom narcotic. Thus, the leaves of Rhododendron, Kalmia, and all the related plants, are deleterious (being stimulant narcotics), or suspicious. The honey made from their flowers is sometimes poisonous. The Uva-Ursi and the Chimaphila (Pipsissewa) are the chief medicinal plants of 924 930 the order. The berries are generally edible, and some are largely used for the dessert; as Cranberries, Pdueberries, and Huckleber- ries. The fleshy calyx of Gaultheria (Checkerberry, or Winter- green) has a very pleasant and well-known aroma. Many Ericaceae are cultivated for ornament, especially Rhododendrons and Azaleas, Heaths and Epacrises. FIG. 922. Pyrola chlorantha, reduced in size. 923. Enlarged flower. 924. Magnified sta- men. 925. Pistil. 926. Cross-section of the capsule. 927. A highly magnified seed. 928. The nucleus removed from the loose cellular testa, and divided, showing the very minute embryo. FIG. 929. Monotropa uniflora. 930. A petal. 931. Capsule, with the stamens. 932 Trans- verse section of the same; the thick and lobed placenta covered with very minute seeds.442 ILLUSTRATIONS OF TIIE NATURAL ORDERS. 858. Ol'll. Aquifoliace® {Ilolhj Family). Trees or shrubs, com- monly with coriaceous leaves, and small axillary polygamous flowers. Calyx of four to six sepals. Corolla four- to six-parted or cleft: the stamens as many as its segments and alternate with them, in- serted on the base of the corolla. Anthers opening longitudinally. Ovary two-to six-celled; the cells with a single suspended ovule. Fruit drupaceous, with two to six nutlets. Embryo minute, in hard albumen. — Ex. Ilex, the Holly, &c. The bark and leaves contain a tonic, bitter, extractive matter. The leaves of a species of Ilex are used for tea in Paraguay: and the famous black drink of the Creek Indians is prepared from the leaves of Ilex vomitoria (Cas- sena) ; which are still used as a substitute for tea in some parts of the Southern States. 859. Ord. EbenacCBB {Ebony Family). Trees or shrubs, destitute of milky juice, with alternate, mostly entire leaves, and polygamous flowers. Calyx three- to six-cleft, free from the ovary. Corolla three- to six-cleft, often pubescent. Stamens twice to four times as many as the lobes of the corolla, inserted on them. Ovary three- to several-celled; the style with as many divisions. Fruit a kind of berry, with large and bony seeds. Embryo shorter than the hard albumen. — Ex. Diospyros, the Persimmon. The fruit, which is extremely austere and astringent when green, becomes sweet and eatable when fully ripe. The bark is powerfully astringent. Eb- ony is the wood of Diospyros Ebenus and other African and Asiatic species. 860. Ord. Styracaceffi {Storax Family). Shrubs or trees, with per- FIG. 933. Perfect flower of Diospyros Yirginiana, the Persimmon. 934. The corolla, laid open, and stamens. 935. The fruit. 936 Section through the fruit and bony seeds. 937. Vertical section of a seed. 938. The detached embryo.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 443 feet flowers. Calyx-tube generally coherent either with the base of the ovary, or with its whole surface. Petals often distinct or nearly so. Styles and stigmas perfectly united into one. Stamens definite, or in the suborder Syjiplocineal mostly indefinite ; filaments more or less united. Cells of the ovary opposite the calyx-lobes. Other- wise much as in the last family.-—Ex. Styrax, Halesia, Symplocos. Some yield a fragrant, balsamic resinous substance ; such as Storax and Benzoin, containing Benzoic acid. The sweet leaves of our Symplocos tinctoria afford a yellow dye. 861. Old. Sapotaces (Sapodilla Family). Trees or shrubs, usually with a milky juice ; the leaves alternate, entire, coriaceous, the up- per surface commonly shining. Flowers perfect, regular, axillary, usually in clusters. Corolla four- to eight- (or many-) cleft. Sta- mens distinct, inserted on the tube of the corolla, commonly twice as many as its lobes, half of them fertile and opposite the lobes, the others petaloid scales or filaments and alternate with them : anthers extrorse. Ovary 4-12-celled, with a single ovule in each cell. Styles united into one. Fruit a berry. Seeds with a bony testa, with or Without albumen. — Ex. Bumelia, of the Southern United States. The fruit of many species is sweet and eatable; such as the Sapodilla Plum, the Marmalade, the Star-Apple, and other West Indian species. The large seeds, particularly of some kinds of Bassia, yield a bland fixed oil, which is sometimes thick and like butter, as in the Chee of India (B. butyracea), and the African Butter-tree. 862. Ord. Myrsinacere. Trees or shrubs, mostly with alternate coriaceous leaves, which are often dotted with glands, and with all the characters of Primulaceae, except the drupaceous fruit and arbo- rescent habit. — Nearly all tropical (Ardisia, Myrsine). 863. Ord. Primulacea; (Primrose Family). Herbs, with opposite, whorled, or alternate leaves, often with naked scapes and the leaves crowded at the base. Flowers regular. Stamens inserted on the tube of the corolla, as many as its lobes and opposite them ! Ovary free, with one partial exception, one-celled with a free central pla- centa ! Ovules mostly indefinite and amphitropous. Style and stigma single. Fruit capsular: the fleshy central placenta attached to the base of the cell. Seeds albuminous. Embryo transverse. — Ex. Primula (Primrose), Cyclamen, Anagallis. In Samolus, the calyx coheres with the base of the ovary, and there is a row of sterile filaments occupying the normal position of the first set of444 ILLUSTRATIONS OF THE NATURAL ORDERS. stamens, namely, alternate with the lobes of the corolla. Several are ornamental in cultivation, such as Primroses and Auriculas. 864. Orel. Plantaginacese (Plantain Family). Chiefly low herbs, with small spiked flowers on scapes, and ribbed radical leaves. — Calyx four-cleft, persistent. Corolla tubular or urn-shaped, scarious and persistent; the limb four-cleft. Stamens four, rarely two, in- serted on the tube of the corolla alternate with its segments ; the per- sistent filaments long and flaccid. Ovary two-celled : style single. Capsule membranaceous, circumcissile ; the cells one- to several- seeded. Embryo large, straight, in fleshy albumen. — Ex. Plantago, the Plantain, or Eibgrass, is the principal genus of the order. Of no important economical qualities. 865. Ol'd. Plumbaginacea; (Leadwort Family). Perennial herbs, FIG. 939. Primula Mistassinica. 940. The corolla removed; its tube laid open. 941. The calyx divided vertically, showing the pistil. 942. Vertical section of the ovary and of the free central placenta, covered with ovules, which nearly fills the cell. 943. Capsule of Primula veris, dehiscent at the summit hy numerous teeth. 944. A magnified seed. 945 Section of the same, exhibiting the transverse embryo. * FIG. 946. Branch of Anagallis arvensis (Pimpernel), with a capsule showing the line of cir- cumcissile dehiscence. 947. The capsule (pyxis), with the lid falling away.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 445 or somewhat shrubby plants; with the flowers often on simple or branching scapes, and the leaves crowded at the base, entire, mostly sheathing or clasping. — Calyx tubular, plaited, five-toothed, persist- ent. Corolla salver-shaped, with a five-parted limb, the five stamens inserted on the receptacle opposite its lobes (Plumbago) ; or else of five almost distinct unguiculate (scarious or coriaceous) petals, with the stamens inserted on their claws! (Statice, &c.) In the former 851 950 953 955 case the five styles are united nearly to the top ; but in the latter they are separate ! Ovary one-celled, with a single ovule pendulous from a strap-shaped funiculus which rises from the base of the cell. Fruit a utricle, or opening by five valves. Embryo large, in thin albumen. — Ex. Statice (Marsh-Rosemary or Sea-Lavender) and Armeria (Thrift) ; sea-side or saline plants. They have astringent roots; none more so than those of our own Marsh-Rosemary or Sea- Lavender, one of the purest astringents of the materia medica. 866. Ord. Lentiblllace® (Bladderwort Family). Small herbs, grow- ing in water, or wet places, with the flowers on scapes ; the leaves either submersed and dissected into filiform segments resembling rootlets, and commonly furnished with air-bladders to render them FIG. 948. A flower of Plantago major, enlarged. 949. Pistil. 950 Capsule (pyxis,) with the marcescent corolla. 951. Cross-section of a pod and seeds. 952. Vertical section of a seed. FIG. 953. Corolla, and 954, calyx of Thrift (Armeria vulgaris). 955 Pistil with distinct styles. 956 Cross-section of the pod and seed. 957. Vertical section of the ovary, magnified,, to show the ovule. 38446 ILLUSTRATIONS OP THE NATURAL ORDERS. buoyant, sometimes evanescent or wanting, or when produced in the air entire and somewhat fleshy, clustered at the base of the scape. Flowers showy, very irregular. Calyx of two sepals, or unequally five-parted. Corolla bilabiate, personate ; the very short tube spurred. Stamens two, inserted on the upper lip of the co- rolla: anthers confluently one-celled. Ovary free, one-celled with a free central placenta ! bearing numerous ovules. Seeds destitute of albumen. Embryo straight.-—-Ex. Utricularia (Bladderwort), Pin- guicula. Unimportant plants. 8C7. Ord. OrobailchacetE (Broom-Rape Family). Hei-bs, destitute of green foliage, and with scales in place of leaves, parasitic on the roots of other plants. Corolla withering or persistent, with a bila- biate or more or less irregular limb. Stamens four, didynamous, 960 959 958 965 inserted on the corolla. Ovary free, one-celled, with two parietal placenta:! which are often two-lobed, or divided. Capsule enclosed FIG. 958. Branch of Epiphegus Yirginiana (Beech-drops), nearly of the natural size: the lower flowers, with short imperfect corollas, alone producing ripe seeds. 959. A flower en- larged. 96Q. Longitudinal section of the same. 961. Longitudinal section of the ovary, more magnified, showing one of the parietal placentae covered with minute ovules. 962. Cross-sec- tion -of the same, showing the two parietal placentae. 963. A highly magnified seed. 964. Section of the same, exhibiting the minute embryo next the hilum. JIG. 965. Aphyllon uniflorum. 966. A flower about the size of nature. 967. The same laid open, showing the didynamous stamens and the pistil. 9G8. A magnified anther. 969. A magnified seed. 970. Section of the 6ame.exogenous or dicotyledonous plants. 447 in the persistent corolla. Seeds very numerous, minute. Embryo minute at the extremity of the albumen. — Ex. Orobanche, Epi- phegus (Beech-drops), &c. Astringent, bitter, and escharotic. The pulverized root of Epiphegus (thence called Cancer-root) is applied to open cancers. 868. Ord. Gcsncriacc®, consisting chiefly of tropical herbs or tender shrubby plants, with green foliage and showy flowers, the calyx often partly adherent to the ovary, agrees with Orobanchaceae in the parietal placentation, structure of the seeds, &c. Many are culti- vated in conservatories for ornament, such as species of Gloxinia and Achimenes. 869. Ord. BignoniacctE (Bignonia Family). Mostly trees, or climbing or twining shrubby plants, with large and showy flowers, and opposite, simple, or mostly pinnately-compound leaves. Corolla with a more or less irregular five-lobed or bilabiate limb. Stamens five, of which one, and often three, are reduced to sterile filaments or rudiments (Fig. 409), or four and didynamous. Ovary one- celled with two parietal placentas, or two-celled by a false partition stretched between the placentae, or rarely by their meeting in the axis. Pod two-valved, many-seeded. Seeds winged (Fig. 601), destitute of albumen. Cotyledons foliaceous, flat, heart-shaped, also notched at the apex. — Ex. Bignonia, Tecoma (Trumpet-creeper), Catalpa, and other tropical genera. Of little importance, except as ornamental plants. 870. Sllbord, Sesame® (Sesamum Family) has few and wingless seeds; the fruit generally indurated or drupaceous, often two- to four-horned, sometimes perforated in the centre from the dissepi- ments not reaching the axis before they diverge and become pla- centiferous, and spuriously four- to eight-celled by the cohesion of parts of the placentae with the walls of the pericarp. — Ex. Sesa- mum, Martynia (Unicorn-plant), and a few tropical plants. They are mucilaginous; and the seeds of Sesamum yield a good fixed oil. 871. Subord. Crescentic®, consists of the Calabash-tree (Crescentia Cujetc) and a few allies, among them Parmentiera edulis, the Can- dle-tree of Panama, which also have wingless seeds. The subacid pulp of the gourd-like fruit is edible; the hard shell is used for bot- tles, or calabashes. 872. Ol'd. Acantliacc® (Acanthus Family). Herbs or shrubby plants, with bracteate showy flowers, and opposite simple leaves, without stipules. Corolla bilabiate, or sometimes almost regularly448 ILLUSTRATIONS OF THE NATURAL ORDERS. five-lobed, convolute in activation ! Stamens four and didynamous, or only two, the anterior pair being abortive or obsolete. Ovary two-celled, with the placentas in the axis, often few-ovuled. Seeds (sometimes only one or two in each cell) usually supported by hooked processes of the placenta, destitute of albumen. The classi- cal Acanthus is the type of this large and chiefly tropical order: its gracefully lobed and sinuated leaves furnished the ornament of the Corinthian capital. They are emollient plants, or some of them bitter or slightly acrid : of little economical use. Several are culti- vated for ornament. 873. Ol'd. ScrophulariacetS (Figwort Family). Herbs, or some- times shrubby plants, with opposite, verticillate, or alternate leaves. 973 972 977 971 974 979 975 976 Corolla bilabiate, or more or less irregular; the lobes imbricated in festivation. Stamens four and didynamous (Fig. 407), the fifth or upper stamen sometimes appearing in the form of a sterile filament FIG. 971. Branch of Gerardia purpurea. 972. Corolla, of the natural size, laid open. 973. Calyx and style of the same. 974. Magnified transverse section of the capsule, with one of the valves removed. FIG. 975. Gratiola aurea, natural size. 976. Corolla laid open, showing the two perfect stamens and two rudimentary filaments as well as the pistil. 977. The perfect stamens and 6terile filament of Chelone. 978. Flower of a Linaria (Toadflax).EXOGENOUS OR DICOTYLEDONOUS PLANTS. 449 (Fig. 408), or very rarely antheriferous, or often only two, one pair being either suppressed or reduced to sterile filaments. Ovary free, two-eelled, with the placentae united in the axis. Capsule two- valved. Seeds indefinite, or sometimes few, albuminous. Embryo small. —- Ex. Scrophularia, Verbascum (Mullein, which is remarkable for the almost regular corolla, and the five often nearly perfect sta- mens), Linaria, Antirrhinum (Snapdragon), &c. — The plants of this large and important order are generally to be suspected of delete- rious (bitter, acrid, or drastic) properties. The most important me- dicinal plant is the Foxglove (Digitalis purpurea), so remarkable for its power of lowering the pulse. Numerous species are cultivated for ornament. 874. Ord. Verbcnacece ( Vervain Family). Herbs, shrubs, or often trees in the tropics, mostly with opposite leaves. Corolla bilabiate, or the four- or five-lobed limb more or less irregular. Stamens mostly four and didynamous, occasionally only two. Ovary free, entire, two- to four-celled. Fruit drupaceous, baccate, or dry, and splitting into two to four indehiscent one-seeded portions. Seeds with little or no albumen. Embryo straight, inferior. — Ex. Verbena (Vervain) is the principal representative in cooler regions. There are many others in the tropics ; one of which is the gigantic Indian Teak (Tectona grandis), remarkable for its very heavy and durable FIG. 979 and 980. Flower of a Verbena enlarged. 981. The corolla laid open. 982. Pistil. 983. The fruit. 984. Cross-section of the young fruit and the contained seeds. 985. Fruit separating into its four cocci. 986. Cross-section of one of the cocci, and a vertical section of the lower part, showing the surface of the contained seed. 987. Vertical section through the pericarp, seed, and embryo. 981 979 982 985 38*450 ILLUSTRATIONS OF THE NATURAL ORDERS. wood. The leaves of Lippia citridora of the gardens yield an agree- able perfume. Others are bitter and aromatic. 875. Subord. 1 PhrymacetE (founded on Fhryma, of a single species) is separated on account of its simple pistil, uniovulate ovary, spirally convolute cotyledons, and superior radicle. 876. Ord. Labiat* (Labiate or Mint Family). Herbs, or some- what shrubby plants, with quadrangular stems, and opposite or sometimes whorled leaves, replete with receptacles of volatile oil. Flowers in axillary cymules, rarely solitary. Corolla bilabiate (Fig. 458). Stamens four, didynamous, or only two, one of the pairs being abortive or wanting. Ovary free, deeply four-lobed; the cen- tral style proceeding from between the lobes. Fruit consisting of four (or fewer) little nuts or schema, included in the persistent calyx. Seeds with little or no albumen. — Ex. The Sage, Rose- 991 989 1002 loot 1000 mary, Lavender, Thyme, Mint, &c. are familiar representatives of this universally recognized order. Their well-known cordial, aro- matic, and stomachic qualities depend upon a volatile oil, contained in glandular receptacles which abound in the leaves and other her- baceous parts, with which a bitter principle is variously mixed. 877. Ord. Borragiliaceic {Borage Family). Herbs, or sometimes shrubby plants, with round stems, and alternate rough leaves ; the FIG. 988. Flower of Nepeta (Glechoma) hederacea, or Ground Ivy. 989. Approximate anthers of one pair of stamens, magnified. 990. Flower of a Lamium. 991. Corolla of L. amplexicaule (Dead Nettle), laid open, showing the didynamous stamens, &c. 992. Calyx and corolla of Scutellaria galericulata (Skull-cap). 993. Section of the enlarged calyx of the same, bringing to view the deeply four-lobed ovary. 994. Cross-section of a magnified achenium. 995. Vertical section of the same, showing the embryo. 996. Flower of Teucrium Canadense. 997. Magnified anther of the same. 998 Stamen of the Thyme. 999. Flower of Monarda. 1000. Magnified anther of the same. 1001. Flower of a Salvia ; the calyx as well as the corolla bilabiate. 1002. Magnified stamen of the same, with widely separated anther-cells, one of which (a) is polliniferous, the other (6) imperfect.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 451 flowers often in one-sided scorpioid clusters (407). Calyx of five leafy and persistent sepals, more or less united at tlie base, regular. Corolla regular ; the limb five-lobed, often with a row of scales in the throat. Stamens as many as its lobes and alternate with them. Ovary deeply four-lobed, the style proceeding from the base of the lobes, which in fruit become little nuts or hard achenia. Seeds with little or no albumen. — Ex. Borage, Lithospermum, Myosotis, Cyno- glossum (Hound’s-Tongue), Heliotropium, &c. In Echium, the limb of the corolla is somewhat irregular, and the stamens unequal. In- nocent mucilaginous plants with a slight astringency: hence demul- cent and pectoral; as the roots of the Comfrey. The roots of An- chusa tinctoria (Alkanet) and Lithospermum canescens, &c. (used by the aborigines under the name of Puceoon) yield a red dye. 878. SubOl'd. ? Cordiacesc consists of tropical woody plants, with the ovary entire (not four-lobed), but in fruit drupaceous or dry and indehiscent, four-seeded. The cotyledons of Cordia are plaited lon- gitudinally (and are often edible), and the style is twice forked. 879. Ol’d. IlydrophyllaCC* (Water-leaf Family). Herbs, usually with alternate and lobed or pinnatifid leaves ; the flowers mostly in cymose clusters or unilateral racemes. Calyx five-cleft, with the FIG. 1003. Myosotis, or Forget-me-not. 1004. The rotate corolla laid open, showing the scales of the throat, and the short stamens. 1005. The pistil with its four-lobed ovary. 1006. The calyx in fruit; two of the little nuts having fallen away from the receptacle. 1007. Sec- tion of a nut, or rather achenium, showing the embryo. 1008 Raceme of Symphytum offici- nale (Comfrey). 1009. A corolla laid open; exhibiting the lanceolate and pointed scales of the throat, alternate with the stamens.452 ILLUSTRATIONS OF THE NATURAL ORDERS. sinuses often appendaged, persistent. Corolla regular, imbricated or convolute in restivation, usually furnished with scales or honey-bear- ing grooves inside ; the five stamens inserted into its base, alternate with the lobes. Ovary free, with two parietal placentae, which in Hydrophyllum dilate in the cell and appear like a kind of inner peri- carp in the capsular fruit. Styles partly united. Seeds few, or sometimes numerous, amphitropous, crustaceous. Embryo small, in hard albumen. — Ex. Hydrophyllum, Nemophila, and Phacelia; nearly all North American plants, some of them handsome and now well known in cultivation. To this order, as a tribe, is now joined the Hydro le^e (formerly the order Ifi/droleacece), having often entire leaves, two distinct styles, a commoidy two-celled ovary by the union of the two placentae in the axis, and numerous seeds with a fleshy albumen. These are chiefly tropical or subtropical herbs, or low shrubs. FIG. 1010. Hydrophyllum Yirginioum. 1011. A flower, nearly of the natural size. 1012. Corolla laid open. 1013. Capsule, with the persistent calyx and style. 1014. Magnified seed. 1015. Section of the same. 1016. Highly magnified embryo.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 453 880. Ord. Polemoniacecc (Polemonium Family). Herbs, with alter- nate or opposite leaves, and panicled, corymbose, or clustered flow- 1017 1018 1020 1019 ers. Calyx five-cleft. Corolla regular, with a five-lobed limb, con- volute in aestivation. Stamens five, inserted on the corolla alternate 1033 1034 iocs with its lobes, often unequal. Ovary free, three-celled, with a thick FIG. 1017. Flowers of Polemonium. 1018. Flowers of Phlox. 1019. Corolla of the same, laid open, showing the stamens unequally inserted on its tube. 1020. Pistil of the same. 1021. Cross-section of the capsule of Polemonium. 1022. Cross-section of a magnified seed. 1023. Perpendicular section of the same. 1024. Magnified embryo. 1025. Cross-section of the dehiscent capsule of Collomia. 1026,1027. Capsule of Leptodaetylon. FIG. 1028. Pyxidanthera barbulata, of the Pine-barrens of New Jersey, natural size. 1029. Pistil, in fruit, and calyx, enlarged. 1030. Corolla and stamens. 1031. Same, laid open. 1032. A separate stamen, magnified. 1033. Section of the dehiscent capsule. 1034. A seed.454 ILLUSTRATIONS OF THE NATURAL ORDERS. axis, bearing few or numerous ovules : styles united into one : stig- mas three. Capsule three-valved, loculicidal; the valves also usu- ally breaking away from a thick central column which bears the seeds. Embryo straight, in fleshy or homy albumen. — Ex. Pole- monium (Greek Valerian), Phlox, Gilia. Chiefly North Amer- ican ; many are very common ornamental plants in cultivation. To this order Diapensia and Pyxidanthera (formerly the order Dia- pensiacece) are now appended, with some doubt. They are two low, tufted or prostrate, suffruticose plants, with crowded and ever- green, lieath-like leaves, and solitary flowers : their principal peculi- arity is found in the transversely dehiscent anthers. 881. Ol’ll. Clinvolvulaccte (Convolvulus Family). Twining or trail- ing herbs or shrubs, with more or less milky juice ; the leaves alter- nate, and the flowers regular. Calyx of five imbricated sepals, per- sistent. Corolla supervolute in ajstivation ; the limb often entire (Fig. 452). Stamens five, inserted on the tube of the corolla near the base. Ovary free, two- to four-celled, with one or two erect ovules in each cell. Capsule two- to four- (or by obliteration one-) celledthe valves often falling away from the persistent dissepi- ments (septifragal, Fig. 587). Seeds large, with a little mucilagi- nous albumen : embryo curved, and the foliaceous cotyledons usually crumpled (Fig. 122, 123).—Ex. Morning-Glory, Bindweed. They contain a peculiar strongly purgative resinous matter, which is FIG. 1035. Ipomoea purpurea. 1036. The pistil. 1037. Section of the capsule, and of the two seeds in each cell. 1038. Capsule (reduced in size), when the valves have fallen away from the dissepiments; and one of the seeds. 1039. Magnified cross-section of a seed. 1040. Em- bryo, with the leaf like two-lobed-cotyle'dons spread out. 1041. Same, with the two cotyledons separated and laid open.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 455 chiefly found in their thickened or tuberous roots. Convolvulus Jalapa, and other Mexican species, furnish the Jalap of the shops. The more drastic Scammony is derived from the roots of C. Scam- monia of the Levant. There is much less of this in those of Con- volvulus panduratus (Man-of-tlie-Earth, Wild Potato-vine) : while those of C. macrorliizus of the Southern States, which sometimes weigh forty or fifty pounds, are farinaceous, with so slight an ad- mixture of this matter as to he quite inert; as is also the case with the Batatas, or Sweet Potato, an important article of food. — To this family are appended, as tribes or suborders, 882. Sllbord. DichondrefC. Ovaries two to four, either entirely distinct or with their basilar styles more or less united in pairs. Creeping plants, with axillary, scape-like, one-flowered peduncles. — Ex. Dichondra. 883. SutlOI'd. Cuscutinca:. Ovary two-celled ; the capsule opening by circumcissile dehiscence, or bursting irregularly. Embryo fili- form, and spirally coiled in fleshy albumen, destitute of cotyledons ! 1043 Parasitic, leafless, twining herbs, destitute of green color. Stamens usually furnished with fringed scales within.—Ex. Cuscuta (Dodder). FIG. 1042. A piece of Cuscuta Gronovii, the common Dodder of the Northern United States, of the natural size. 1043. A flower, enlarged. 1044. The same, laid open. 1045. Section of the ovary. 1046. Section of the capsule and seeds. 1047. The spiral embryo detached. 1048. The same in germination.456 ILLUSTRATIONS OF THE NATURAL ORDERS. 884. Ol’d. SolaiiaCC® (Nightshade Family) differs from Scrophu- lariacea; chiefly in the regular (rarely somewhat irregular) flowers, with as many fertile stamens as there are lobes to the corolla (four or five), and some form of the plaited or valvate festival ion of the corolla. Fruit either capsular or baccate. Embryo slender, mostly curved, in fleshy albumen (Fig. 614, 615). — The fruit of Datura is spuriously four-celled. — Stimulant narcotic properties pervade the order, the herbage and fruits of which are mostly deleterious, often violently poisonous, and furnish some of the most active medi- cines ; such as the Tobacco, the Henbane (Hyoscyamus niger), the Belladonna (Atropa Belladonna), the Thorn-apple or Jamestown Weed (Datura Stramonium), and the Bittersweet (Solanum Dulca- mara). Yet the berries of some Solanums art! eatable (as Toma- toes, the Egg-Plant, &c.), and the starchy tubers of the Potato are a great staple of food. But the fruit and seeds of Capsicum ( Cayenne pepper) are most pungent and stimulant. 885. Ol'd. Gciltianacepc {Gentian Family). Herbs, with a watery juice; the leaves opposite and entire. Flowers regular, often showy. Calyx of usually four or five persistent, more or less united sepals. Corolla mostly convolute in ajstivatian; the stamens inserted on its tube. Ovary one-celled, with two parietal and many-ovuled pla- FIG. 1049. Flower of Tobacco (Nicotiana Tabacum). 1050 The capsule, dehiscent; at the apex, with the persistent calyx. 1051. Cross-section of the same. 1052. Magnified section of the seed of Solanum. 1053. Flower of Hyoscyamus niger. 1054. Fruit (pyxis) of the same. 1066. Flowers and berries of Solanum Dulcamara.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 457 cento', sometimes tlie ovules dispersed over the whole cavity of the ovary, or nearly so. Capsule many-seeded. Seeds often very small, with fleshy albumen and a minute embryo. — Ex. Gentiana, Frasera (the American Columbo). A pure bitter and tonic principle ( Gen- tianine) pervades the whole order. Gentiana lutea of Middle Europe furnishes the officinal Gentian, for which almost any of our species may be substituted. The above applies to the proper Gen- tian Family. Obolaria differs in the imbricative aestivation of the 1057 1C63 corolla: as to the ovules lining the whole cavity of the ovary, this is also the case in Bartonia (Centaurella, Michx.), and in some Gen- tians.— The Buekbean is the type of the tribe MenyanthidEjE, which has alternate, sometimes trifoliolate or toothed leaves, and a valvate-induplicate aestivation of the corolla. 886. Ol'd. Apocynacetc (Dogbane Family). Trees, shrubs, or herbs, with milky juice, and opposite entire leaves, without stipules. Flowers regular. Corolla five-lobed, mostly convolute or twisted in mstivation. Filaments distinct; the anthers sometimes slightly connected: pollen powdery. Ovaries two, distinct, or rarely syn- carpous, but their styles or stigmas combined into one. Fruit com- monly a pair of two follicles. Seeds often with a coma. Embryo large and straight, in albumen. — Ex. Apocynum (Dogbane), Vinca FIG. 1056. Flower of Gentiana angustifolia 1057. Corolla, and 1058, the calyx, laid open. 1059. The pistil. 1060. Cross-section of the pistil, showing the parietal attachment of the ovules. 1061. Ripe capsule of G. saponaria, raised on a stipe: the persistent withering corolla, &c torn away. 1062. A magnified seed, with its large and loose testa. 1063. Leaf of Limnanthemum lacunosum, bearing the flowers on its petiole ! 39458 ILLUSTRATIONS OF THE NATURAL ORDERS. (Periwinkle), Nerium (Oleander), and a great number of tropical shrubs and trees. In nearly all, the juice is drastic or poisonous; it often yields Caoutchouc ; which in Sumatra is obtained from Ur- ceola elastiea, and in Madagascar from Yahea. Strangely enough some species yield a sweet and harmless milk, such as Tabemse- montana utilis, one of the South American Cow-trees. Also the fruit of several species is edible and even delicious ; that of others is a deadly poison. One kernel of Tangliinia venenifera of Mad- 1067 1066 1064 agascar will kill twenty people. The inner bark of Dogbane makes a strong cordage, whence its name of Indian Hemp. 887. Ord. Asclepiadaceae (Milkweed Family). Herbs or shrubs, with milky juice, and mostly opposite entire leaves ; mainly differ- ing from the preceding order (as they do from all other Exogenous plants) by the peculiar connection of the stamens with the stigma, and the cohesion of the pollen into wax-like or granular masses, which are attached in pairs to five glands of the stigma, and re- moved from the anther-cells usually by the agency of insects (Fig. 541-545). Fruit consisting of two follicles. Seeds usually with a silky coma and a large embryo. — Ex. Asclepias (Milkweed, or Silkweed). The juice of the A. tuberosa (Pleurisy-root, Butterfly- weed) is not milky. In all, it is bitter and acrid, and contains Caoutchouc. The roots, Ac. are diaphoretic, emetic, or cathartic. The inner bark yields abundance of very long and fine, extremely FIG. 1064. Apocynum androsaemifolium. 1065. Flower, of the natural size. 1066. Sta- mens with the anthers conniveut around the pistils. 1067. The pistils with their large com- mon stigma. 1068. Seed with its coma, or tuft of silky hairs.EXOGENOUS OH DICOTYLEDONOUS PLANTS. 459 strong fibres. The singular structure of the blossom may be learned from Fig. 541 -545, and the subjoined illustrations. 1070 1072 1073 1089 1078 1079 1074 1075 1080 1077 888. Orel. JasmiliacCiB (Jessamine Family) consists of a few chiefly Asiatic shrubs, with compound leaves and fragrant flowers ; differ- ing from Olcacese by the imbricated or twisted aestivation of the hypocrateriform corolla, the erect seeds, &c. — Ex. Jasminum, the Jessamine. Cultivated for ornament, and for their very fragrant blossoms. — Menodora, or Bolivaria, has mostly simple leaves and four ovules in each cell, but evidently pertains to this order. 889. Old. OleacetC (Olive Family). Trees or shrubs, with oppo- site leaves, either simple or pinnate. Calyx persistent. Corolla FIG. 1069. Flower-bud of the common Milkweed (Asclepias Cornuti). 1070 Expanded flower ; the calyx and corolla reflexed; showing the stamineal crown 1072. One of the hood- ed appendages of the latter removed and seen sidewise, with its included process or horn. 1073. A vertical section of a flower (the hooded appendages removed) through the tube of sta- mens, the thick stigma, ovaries, &c. 1074 Flower with the calyx and the fertilized enlarging ovaries, crowned with the large stigma common to the two, from the angles of the peltate sum- mit of which the pairs of pollen-masses, detached from the anther cells, hang by their stalks or caudicle from a gland. 1075. Fruit (follicle) of the Common Milkweed. 1076. Cross-section of the last, in an early state. 1077. Detached placenta in fruit, covered with seeds. 1078. Seed (cut across), with its coma 1079 Section of the seed, parallel with the cotyledons. 1080. Vertical section of the seed perpendicular to the face of the cotyledous.460 ILLUSTRATIONS OF THE NATURAL ORDERS. four-cleft, or of four separate petals, valvate in [estivation, sometimes none. Stamens mostly two, adnate to the base of the corolla. Ovary free, two-celled, with two pendulous ovules in each cell. Fruit by suppression usually one-celled and one- or two-seeded. Seed albuminous. Embryo straight. — Ex. Olea (the Olive), and Chionanthus (Fringe-tree), where the fruit is a drupe. Syringa, the Lilac, which has a capsular fruit. Fraxinus, the Ash ; where the fruit is a samara, the flowers are polygamous, and mostly destitute of petals. Olive oil is expressed from the esculent drupes of Olea Euro pom. The bark, like that of the Ash, is bitter, astringent, and febrifugal. Manna exudes from the trunk of Fraxinus Ornus of Southern Europe, &c.—-Forestiera appears to represent another entirely apetalous form of this family. Division III. — Apetalous Exogenous Plants. Corolla none ; the floral envelopes consisting of a single series (calyx), or sometimes entirely wanting. — Many of them are apeta- lous allies of polypetalous families; as Phytolaccacete, &e. related to Caryophyllacem ; Empetracete to Ericaceae, &c. Conspectus of the Orders. Group 1. Flowers perfect, with a conspicuous or colored mostly adnate calyx. Ovary scveral-celled and many-ovulcd. Capsule or berry many-seeded. — Herbs or climbing shrubs. Aeistolochiaceje. Group 2. Flowers perfect, or rarely polygamous. Calyx corollinc, strongly gamosepalous, much produced beyond the ovary, the expanded border entire or moderately lobed; the base persistent, and forming an indurated nut- like closed covering to the one-seeded achcnium or utricle. Embryo large, curved or conduplicate, involving some albumen. — Leaves opposite : nodes tumid. Flowers often large and showy. Nyctag inacc.e. Group 3. Flowers perfect, or rarely polygamous, with a regular and often pctaloid calyx. Ovary free. Ovules solitary in each ovary or cell. Em- bryo curved or coiled around (or sometimes in) mealy albumen, rarely in the axis or exalbuminous. Ovary sevcral-celled, or ovaries several in a whorl. Phytolaccaceas. Ovary solitary and one-celled, with a single ovule. Stipules none. Ovule campylotropous or amphitropous.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 461 Calyx corolline, double. Stamens perigynous. Basellace.®. Calyx not corolline : no scarious bracts. Chenopodiace®. Calyx and bracts scarious, sometimes colored. Amarantace®. Stipules sheathing. Calyx corolline. Ovule orthotropous. Polygonace®. Group 4. Flowers perfect, polygamous or dioecious, not disposed in aments, with a regular and often petaloid calyx. Style or stigma one. Ovary one-cellcd, with one or few ovules : but the fruit one-eelled and one-seeded. Embryo not coiled around albumen. — Trees or shrubs, rarely herbs. Calyx free from the ovary, and not enveloping the fruit. Flowers polygamo-dioeeious. Anthers opening by valves. Flowers perfect. Anthers opening longitudinally. Calyx free, but baccate in fruit and enclosing the acheniuin. Calyx adnate to the ovary. Ovule destitute of coats. Ovules several, pendulous from a stipe-like placenta. Ovule solitary, suspended. Parasitic shrubs. Laurace®. Thymelace®. Eleagnace®. Santalace®. LORANTHACE®. Group 5. Flowers perfect, in spikes which often appear like aments, achlamyde- ous. Ovaries solitary or several, with one or few erect or ascending orthotropous ovules. Embryo minute, enclosed in a persistent embryo-sac at the apex of the albumen. — Herbs or shrubby plants, with tumid nodes. Ovary one, one-ovuled. Stipule opposite the leaf or none. Piperace®. Ovaries more than one. Stipules, when present, in pairs. Saururace®. Group 6. Flowers perfect or diclinous, frequently destitute of both calyx and corolla. — Submersed or floating aquatic herbs. Flowers monoecious. Fruit one-celled, one-seeded, Ceratophyllace.se. Flowers mostly perfect. Fruit four-celled, four-seeded. ( ali.ii r i chace®. Flowers mostly perfect. Pod sevcral-celled, several-seeded. Podostemace®. Group 7. Flowers monoecious or dioecious, not amentaceous. Fruit capsular or drupaceous, with two or more cells, and one (or rarely two) seeds in each cell. Embryo straight in the axis of the albumen. — Herbs, shrubs, or trees. Fruit mostly diy. Juice milky. Pollen simple. Egphorbiace®. Fruit drupaceous. Pollen compound ; the grains in fours. Emfetrace®. Group 8. Flowers monoecious, dioecious, or polygamous, with a regular calyx which is free from the one-celled (or rarely two-celled) ovary and one- seeded fruit (achenium, drupe, or samara), but sometimes enclosing it. Embryo curved, or straight, with the radicle superior, in albumen when there is any. — Inflorescence various, often in spikes, heads, or a sort of aments. Urticace®. Group 9. Flowers monoecious or dioecious, the sterile, and frequently the fertile also, in aments, or in heads or spikes. Calyx of the fertile flowers, if any, adherent. Ovary often two- to several-celled, but the fruit always one- celled. — Trees or shrubs. 39 *462 ILLUSTRATIONS OF TIIE NATURAL ORDERS. Stipules sheathing. Nutlets club-shaped, in globular heads. Stipules not sheathing or none. Sterile flowers only amentaceous. Fruit a kind of drupaceous nut. Leaves pinnate. Fruit a dry nut, involucrate. Leaves simple. Both kinds of flowers amentaceous. Fruit a samara or a small dry drupe. Ovary one-celled : ovule solitary, erect. Ovary two-celled, two-ovuled : ovule pendulous. Fruit a many-seeded follicle : seeds with a coma. Platanacea^ Juglandacea:. CurULIFERAi. Myricacea:. Betulacea:. Salicaceac. 890. fll'd. Aristolochiace® (Birihwort Family). Herbaceous or climbing shrubby plants, with alternate leaves. Flowers brown or greenish, usually solitary. Calyx-tube more or less united with the ovary; the limb valvate. Stamens six to twelve, epigynous, or adherent to the base of the short and thick style : anthers adnate, 1081 1083 1081 1085 1082 extrorse. Ovary 3 - 6-eelled. Capsule or berry three- to six-celled, many-seeded. Embryo minute, in fleshy albumen. — Ex. Asarum (Wild Ginger, Canada Snakeroot), Aristolochia (Virginia Snake- root). Pungent, aromatic, or stimulant tonics; generally termed Snakeroots, being reputed antidotes for the bites of venomous snakes. FIG. 1081. Asarum Canadense. 1082. Calyx displayed, and a vertical section through the rest of the flower. 1083. Cross-section of the ovary; the upper portion (from which the limb of the calyx is cut away) showing the stamens, the united styles, &c. 1084. A separate sta- men, enlarged. 1085. Vertical section of a seed.EXOGENOUS OE DICOTYLEDONOUS TLANTS. 4C3 891. Ord. Rafflesiaceffi : parasitic flowers, or flower-clusters (152), of which the most striking is the gigantic Eafflesia Arnoldi of Sumatra (Fig. 150), perhaps as much related to the last order as to any. 892. Ord. Nyctaginaceae (Four-o'clock Family). Herbs or shrubs, with opposite leaves ; distinguished by their tubular and funnel-form calyx, the upper part of which resembles a corolla, and at length separates from the base, which latter hardens and encloses the one- celled achenium-like fruit, appearing like a part of it. Stamens hy- pogynous, 1 - 20. Embryo coiled around mealy albumen (Fig. 616, 617) ; cotyledons large. Flowers involucrate. Mirabilis (Four- o’clock) has a one-flowered involucre exactly like a calyx, while the real calyx resembles the corolla of a Morning-Glory. Abronia has only one cotyledon to its embryo! — Plants of warm latitudes; many occur on our Southwestern frontiers. 893. Ord. Phytolaccaceac (Poke-weed Fa?nihj). Chiefly represented FIG 1086, 1087. Phytolacca decandra (Pokeweed). 1088 A flower. 1089. Unripe fruit. 1090. Cross-section of the same, a little enlarged. 1091. Magnified seed. 1092. Section of the same across the embryo. 1093. Vertical section, showing the embryo coiled around the albu- men into a ring 1094. Magnified detached embryo.4C4 ILLUSTRATIONS OF THE NATURAL ORDERS. by the common Poke (Phytolacca decandra), which has a compound ovary of ten confluent (one-seeded) carpels, the short styles or stig- mas distinct; the fruit a berry. The root is acrid and emetic: yet the young shoots in the spring are used as a substitute for Aspara- gus. The berries yield a copious deep-crimson juice. 894. Orel. Bascllacesc; a small Subtropical group of climbing suc- culent plants, allied to the last and the next two orders, from which it differs by the decidedly perigynous stamens and double petaloid calyx.. The ovary is single and one-ovuled. — Ex. Basella, Bous- singaultia of South America; the latter cultivated for ornament (from potato-like tubers) under the name of Madeira Vine. Some are pot- herbs. 895. Ol'd, Chenopodiacesc (Goosefoot Family). Chiefly weedy herbs, with alternate or opposite and more or less succulent leaves, 1096 1101 1104 1107 and small herbaceous flowers. Calyx sometimes tubular at the base, persistent; the stamens as many as its lobes, or fewer, and in- serted at their base. Ovary free, one-celled, with a single ovule arising from its base. Fruit a utricle (Fig. 574) or achenium. Embryo curved or coiled around the outside of mealy albumen, or spiral without any albumen (in Salsola, &c.).— Ex. Chenopodium, Atriplex, Beta (the Beet), &c. Sea-side plants, or common weeds : FIG. 1095. Part of the spike of Salicornia herbacea: the flowers placed three together in excavations of the stem, protected by a fleshy scale. 1096. Separate flower. 1097. A flower of Blitum, with its fleshy calyx and single stamen. 1098. Same, more enlarged, with the thick- ened juicy calyx (1099) removed. 1100. The ripe fruit. 1101. Same, divided vertically, show- ing the embryo coiled arouud the central albumen. 1102. Flower of Chenopodium album (common Goosefoot). 1103 Section of the same, more enlarged. 1104. Section of the utricle and seed, showing the embryo. 1105. Calyx of Salsola kali (Saltwort), in fruit, with its wing-, like border. 1106. Section of the same, bringing the ovary into view. 1107. The spirally coiled embryo of Chenopodina maritima.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 465 some are pot-herbs, such as Spinach : a few are cultivated for their esculent roots ; as the Beet, which yields sugar. Soda is extract- ed from the maritime species, especially from those of Salsola and Salicornia (Samphire, Glass-wort). Chenopodium anthelminticum yields the well-known Worm-seed oil. 896. Ord. Amarantacete (Amaranth Family). Flowers in heads, spikes, or dense clusters, imbricated with dry and scarious bracts which are often colored. Calyx of three to five sepals, which are dry and scarious like the bracts. Stamens five or fewer, hypogy- nous, distinct or monadelphous: anthers frequently one-celled. Utri- cle often opening as a pyxis (Fig. 575). Embryo annular, always vertical. Otherwise nearly as in Chenopodiaceaj. — Amarantus, &c. A few Amaranths (Coxcomb, &c.) and Globe Amaranths (Gomphrena) are cultivated for ornament. But most of the family are coarse and homely weeds (Pigweeds, &c.). 897. Ord. Polygonacete (Buckwheat Family). Herbs with alter- nate leaves; remarkable for their stipules (ochre®, Fig. 305), which PIG. 1108. Polygonum Penneylvanicum. 1109. Flower, laid open. 1110. Section of the ovary, showing the erect ovule. 1111. Section of the seed, showing the embryo, at one side of albumen.466 ILLUSTRATIONS OR THE NATURAL ORDERS. usually form sheaths around the stems above the leaves, and for their orthotropous ovules (Fig. 518,526). Stamens definite, inserted on the petaloid calyx. Fruit achenium-like. Embryo curved, or nearly straight, applied to the outside (rarely in the centre) of starchy albumen (Fig. 606). — Ex. Polygonum, Rumex (Dock, Sorrel), Rheum (Rhubarb). The stems and leaves of Rhubarb and Sorrel are pleasantly acid : while several Polygonums (Knot- weed, Smart-weed, Water Pepper, &c.) are acrid or rubefacient. The farinaceous seeds of P. Fagopyrum (the Buckwheat) are used for food. The roots of most species of Rhubarb are purgative : but it is not yet known what particular species of Tartary yields the genuine officinal article. The Eiiiogone.® (a large tribe of the southern and western parts of North America, chiefly west of the Rocky Mountains) are remarkable for their exstipulate leaves and involucrate flowers. 898. Ol'd. Lauracca! (Laurel Family). Trees or shrubs, with pellucid-punctate alternate leaves, their margins entire. Flowers sometimes polygamo-dioecious. Calyx of four to six somewhat united petaloid sepals, which are imbricated in two series, free from the ovary. Stamens definite, but usually more numerous than the sepals, inserted on the base of the calyx : anthers two- to four- celled, opening by recurved valves ! Fruit a berry or drupe, the pedicel often thickened. Seed with a large almond-like embryo, 1114 1116 1117 destitute of albumen. — Ex. Laurus, Sassafras, Benzoin. All aro- matic plants, almost eveey part abounding in warm and stimulant FIG. 1112. A staminate, and 1113, a pistillate flower of Sassafras. 1114. A stamen with its glands at the base : the anthers opening by two sets of valves. 1115. Pistil; the ovary divid- ed. 1116 Branch in fruit. 1117. Section of the drupe and seed.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 467 volatile oil, to which their qualities are due. Camphor is obtained from Camphora officinarum of Japan, China, &c. Cinnamon is the bark of Cinnamomum Zeylanicum ; Cassia baric, of Cinnamomum aromaticum of China. The aromatic bark and wood and the very mucilaginous leaves of our own Sassafras are. well known. Our Benzoin odoriferum is the Spice-wood, or Feverbush. Laurus nobilis is the true Laurel, or Sweet Bay. Persea gratissima, of the West Indies, bears the edible Avocado pear. 839. Ord. Thymelaceffi (Mezereum Family). Shrubby plants, with perfect flowers, and a very tough bark; the tube of the petaloid ■ calyx being free from the (one-ovuled) ovary ; its. lobes imbricated in aestivation ; the pendulous seed destitute of albumen. Stamens often twice as many as the lobes of the calyx, inserted upon its tube 1119 1120 or throat. — Ex. Daphne and Dirca (Leather-wood, Moose-wood, Wickopy, which is the only North American genus). The tough bark is acrid, or even blistering, and is also useful for cordage. The reticulated fibres of the liber in the Lagetta or Lace-bark of Jamaica may be separated into a kind of lace. The berries are more or less deleterious. 900. Orel. Eleagnacere (Oleaster Family): Shrubs or small trees, with the flowers more commonly dicecious ; readily distinguished from the preceding by having the foliage and shoots covered with scurf, by the ascending albuminous seed, and the persistent tube of FIG. 1118. Flowering branch of Dirca palustris. 1119. A flower. 1120. The same, laid open and enlarged. 1121. Branch in fruit.468 ILLUSTRATIONS OF THE NATURAL ORDERS. the calyx, which, although free from the ovary, becomes succulent, like a berry in fruit, and constricted at the throat, enclosing the crustaceous achenium. — Ex. Eleagnus, Shepherdia. Plants of no economical importance, except that a few are cultivated for their silvery foliage. The fruit is sometimes eaten, as is that of the Buf- falo-berry (Shepherdia argentea) and Silver-berry (Eleagnus ar- gentea) by the Northern aborigines. 901. Ord. Proteacese (Protea Family). A rather large family of shrubs and trees of Southern temperate and subtropical regions, chiefly of the Cape of Good Hope and Australia (a few in South America, &e.), with rigid coriaceous leaves, perfect flowers, either regular or irregular, mostly in heads or spikes ; the lobes of the calyx valvate in asstivation ; a stamen borne on each of its four lobes ; the pistil simple and free, forming a mostly dehiscent fruit; seeds with a large and straight embryo, and no albumen. Many of these plants are prized in conservatories for their beauty or sin- gularity : the seeds of a few species are eaten. 902. Ord. Santalaceoe (Sandal-wood Family). Trees, shrubs, or sometimes herbs (their roots inclined to form parasitic attach- ments) ; with alternate entire leaves, and small (very rarely dioe- cious) flowers. Calyx-tube adherent to the ovary; the limb four- or five-cleft, valvate in {estivation ; its base lined with a fleshy disk, the edge of which is often lobed. Stamens as many as the lobes of FIG. 1122. Branch of Comandra umbellata. 1123. Enlarged flower, laid open. 1124. Yer* tical section of a flower. 1125 One of the segments of the calyx, enlarged, showing the tuft of hairs which connects its surface with the anther ! 1126. The fruit, reduced in size.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 4G9 the calyx, and opposite them, inserted on the edge of the disk. Ovules several, destitute of proper integuments, pendulous from the apex of a stipe-like basilar placenta. Style one. Fruit indehiscent, crowned with the limb of the calyx. Seed albuminous. Embryo small. — Ex. Comandra, Pyrularia, &c. The fragrant Sandal-wood is obtained from several Indian and Polynesian species of Santalum. The large seeds of Pyrularia oleifera (Buffalo-tree, Oil-nut), of the Alleghany Mountains, would yield a copious fixed oil. One species of Fusanus in Australia is esteemed for its edible seeds, known by the name of Quandang-nuts. 903. Ord. Loranthacc® (Mistletoe Family) consists of shrubby plants, with articulated branches, and opposite coriaceous and mostly dull greenish entire leaves; parasitic on trees. The floral envelopes are various. In Mistletoe (which is dioecious) the anthers are ses- sile and adnate to the face of the sepals, one to each; while Lo- ranthus has both calyx and corolla, the latter most conspicuous, and a stamen before each petal and adnate to it. The ovary is one- celled, with a single suspended ovule, consisting of a nucleus without integuments. Fruit a one-seeded berry. Embryo small, in fleshy albumen. — Ex. Loranthus ; Viscum, the Mistletoe, from the glu- tinous berries of which birdlime is made; Phoradendron, the Ameri- can Mistletoe. The bark is astringent. 904. Ol'd. Pipcraccffi (Pepper Family). A peculiar order of tropical herbaceous or shrubby plants, with jointed stems, naked (achlamyde- ous) but perfect flowers in spikes or spicate racemes, a one-celled ovary with an erect orthotropous ovule; the embryo minute in a vitellus or persistent embryo-sac at the apex of the albumen. — Pungent and stimulant properties characterize the order. . Piper nigrum fur- nishes Black pepper, and White pepper is the same, with the flesh of the drupe removed. The fruit of Cubeba officinalis, &c. furnishes Cubebs, which are hot aromatics, acting also on the mucous mem- branes. The pungency in all these plants is owing to a peculiar volatile oil and resin. They also yield a crystalline matter, called Piperine. Others have more intoxicating properties, as Betel, the leaves of a Chavica, chewed by the Malays, and the Ava (Macropi- per methysticum) from which the South-Sea Islanders make their inebriating drink. 905. Ord. Sauniracca: (Lizard's-tail Family) ; differs from the Pep- per Family (of which it is an offshoot) in the feebly pungent quali- ties, the distinct stipules (when these are evident), and the three or 40470 ILLUSTRATIONS OF T1II5 NATURAL ORDERS. more ovaries, separate or somewhat united, with one or more ovules in each. — Ex. Saururus, Hottuynia : a small group. 1128 1129 906. Ord. Ccratopliyllacese (Homwort Family) consists of the single genus Ceratophyllum (growing in ponds and streams in many parts of the world) ; distinguished by the whorled and dissected leaves with filiform segments; the flowers monoecious and sessile in the axil of the leaves ; the stamens indefinite, with sessile anthers ; and the simple one-eelled ovary, which forms a beaked achenium in fruit, containing an orthotropous suspended seed, with four cotyledons! and a manifest plumule. 907. Ol'd. CallitrichilCeSB (Water-Starwort Family), formed of the genus Callitriche; aquatic annuals, with opposite entire leaves; the axillary flowers (either perfect or monoecious) with a two-leaved FIG. 1127. Saururus cernuus. 1128. A separate flower, with its bract and a part of the axis magnified. 1129. A more magnified anther, discharging its pollen from one cell. 1130. Cross-section of the ovary. 1131. Vertical section of one of the carpels in fruit, and of the contained seed, with the sac at the extremity of the albumen, containing the minute embryo. 1132. A seed. 1133. Same, with the outer integument (testa) removed, showing the vitellus. 1134. The latter, highly magnified. 1135. Section of the same, showing the enclosed heart- shaped embryo.EXOGENOUS OK DICOTYLEDONOUS PLANTS. 471 involucre, but entirely destitute of calyx and corolla; stamen one (or rarely two), liypogynous, with a slender filament, and a reni- form confluently one-celled anther; the ovary four-lobed, four-celled, indehiscent in fruit; the seeds albuminous. 1133 1137 908. Ol'd. Podostemaccs (River-weed Family) comprises a few (chiefly American and Asiatic) aquatics, in rivers, with the aspect of Mosses, Hepatic*, &c.; their small flowers arising from a spathe ; the calyx often entirely wanting; the stamens frequently unilateral and monadelphous; the ovary two-' or three-celled, with distinct styles ; in fruit forming a ribbed capsule, containing numerous ex- albuminous seeds attached to a central column. — Ex. Podostemon. 909. Ol’d. Eliphorbiace* (Spurge Family). Herbs, shrubs, or trees, often with a milky juice: in northern temperate climes chiefly represented by the genus Euphorbia ; which is remarkable for hav- ing numerous staminate flowers, reduced to a single stamen (487), enclosed in an involucre along with one pistillate flower, this reduced to a compound pistil, and also aclilamydeous, or with an obsolete calyx. But other genera have a regular calyx both to the staminate and pistillate flowers ; and a few are likewise provided with petals. Ovary of two to nine more or less united carpels, coherent to a cen- tral prolongation of the axis : styles distinct, often two-cleft. Fruit mostly capsular, separating into its elementary carpels, or cocci (usually leaving a persistent axis) : these commonly open elastically FIG. 1136. Callitriche yerna, about the natural size. 1137. Perfect flowers, magnified. 1138. A staminate and pistillate flower, magnified. 1139. The fruit. 1140. Cross-section of the fruit. 1141. Vertical section through the pericarp, seeds, and embryo.472 ILLUSTRATIONS OF THE NATURAL ORDERS. by one or both sutures. Seed with a large embryo in fleshy albu- men, suspended. — Ex. Euphorbia (Spurge), Croton, Buxus (the Box). Acrid and deleterious qualities pervade this large order, chiefly resident in the milky juice. But the starchy accumulations in the rliizoma, or underground portion of the stem, as in the Man- dioc or Cassava (Janiplia Manihot) of tropical America, are per- fectly innocuous, when freed from the poisonous juice by washing and heating. The starch thus obtained is the Cassava, which, when granulated, forms the Tapioca of commerce. The farinaceous albu- men of the seed is also innocent, and the fixed oil which it frequently contains is perfectly bland. But the oil procured by expression abounds in the juices of the embryo and integuments of the seed, and possesses more or less active properties. The seeds of Ricinus com- munis yield the Castor oil: and those of Croton Tiglium, and some other Indian species, yield the violently drastic Croton oil or Oil of FIG. 1142. Flowering branch of Euphorbia corollata; the lobes of the involucre resem- bling a corolla. 1143. Vertical section of an involucre (somewhat enlarged), showing a portion of the staininate flowers surrounding the pistillate flower (a), which in fruit is raised on a Blender pedicel. 1144. One of the staminate flowers enlarged, with its bract, a: b, the pedicel, to which the single stamen, c, is attached by a joint; there being no trace of floral envelopes. 1145. Cross-section of the 3-pistillate fruit. 1146 Vertical section of one of the pistils in fruit (the two others having fallen away fronl the axis), and of the contained seed; showing the em- bryo lengthwise. 1147. A seed.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 473 Tiglium. Some plants of the family are most virulent poisons; as, for example, the Manchineal-tree of the West Indies (Hippomane Manicella), which is said even to destroy persons who sleep under its shade ; and a drop of the juice blisters the hand. The hairs of some species (such as our Cnidoscolus stimulosus) sting like Nettles. Box- wood is invaluable to the wood-engraver. The purple dye called Turnsole is from Crozophora tinctoria. Another most important product of this order is Caoutchouc, which is yielded by various plants of different families; but the principal supply of the article (that of Para, Demarara, and Surinam) is furnished by species of Siphonia. 910. Ord. Empetracc* {Crowherry Family). Low, shrubby ever- greens, with the aspect of Heaths; the leaves crowded and acerose, 1153 1154 with small (dioecious or polygamous) flowers produced in the axils. Calyx consisting of regular imbricated sepals, or represented by im- bricated bracts. Stamens few : pollen of four grains coherent in one, as in Heath. Ovary three- to nine-celled, with a single erect ovule in each cell: style short or none : stigmas lobed and often laciniated. Fruit a drupe, with from three to nine bony nucules. Seeds albuminous; the radicle inferior. — Ex. Empetrum, Ceratiola, Corema; unimportant plants. Probably no more than apetalous Ericaceae ; but the stigmas are peculiar. 911. Ord. Urticaceae (Nettle Family), shrubs, or herbs, with stipules, often with milky juice, and diclinous or polygamous, rarely perfect flowers, furnished with a regular calyx; which is free from the one- FIG. 1148. Branch of Ceratiola ericoides in fruit. 1149. Magnified staminate flower, with its bracts. 1150. The two stamens, with an inner bract or sepal. 1151. Magnified pistillate flower, with its imbricated bracts. 1152. The pistil separate; one of the cells laid open by a vertical section, showing the erect ovule. 1153. Drupe, with the persistent scales at the base. 1154. Transverse section of its endocarp, or two nucules, with the enclosed seed and embryo. 1155. Vertical section of the seed. 40*474 ILLUSTRATIONS OF THE NATURAL ORDERS. celled (sometimes two-celled) ovary and tlie always one-celled and one-seeded fruit, but sometimes enclosing it. Stamens as many as the lobes of the calyx and opposite them, or sometimes fewer. Em- bryo large ; cotyledons mostly broad; the radicle superior in the fruit. Stipules often deciduous. A large and greatly diversified order, comprising at least four well-marked suborders. 912. Subord. Ulmaccae (.Elm Family). Trees or shrubs, with a watery juice, alternate rough leaves, perfect or merely polygamous flowers, two styles or stigmas ; the ovary either one- or two-celled, with one ovule suspended from the summit of each. Fruit either a samara (Fig. 578), with a straight embryo and no albumen, as in 1156 1161 1163 1159 1158 1163' 1162 the Elm (Ulmus) ; or a drupe with a curved embryo and scanty albumen, as in Celtis (Hackberry), the type of the tribe Celtideas. Timber-trees. The inner bark of the Slippery Elm is highly charged with mucilage. Hackberries are edible. 913. Subord. Artocarpctc (Bread-fruit Family) ; which are chiefly tropical trees or shrubs with a milky or yellow juice; the monoe- cious or dioecious flowers mostly aggregated into fleshy heads, and FIG. 1156 Flower of the Slippery Elm. 1157. Calyx laid open and the ovary divided ver- tically. 1158. Fruit, the cell laid open to show the single seed. 1159. The latter magniOed 1160. Its embryo. FIG. 1161. Branch of Celtis Americana, in flower. 1162. Enlarged flower, divided verti- cally. 1163. Drupe, the flesh divided to show the stone. 1163'. The coiled embryo.EXOGENOUS OE DICOTYLEDONOUS PLANTS. 475 forming a multiple fruit, or else enclosed in a dry or succulent invo- lucre. Styles or stigmas commonly two. Ovary ripening into an achenium. Seeds with or without albumen.—Ex. Artocarpus (the Bread-fruit), Morus (the Mulberry, Fig. 593-595), Maclura (the Osage Orange), Ficus (the Fig, Fig. 590-592). The fruit is often innocent and edible, at least when cooked; while the milky juice is more or less acrid or deleterious. It also abounds in Caout- chouc ; much of which is obtained from some South American trees of this order, and from Fiscus elastica in Java. In one instance, how- ever, the milky juice is perfectly innocent; that of the famous Cow- tree of South America, which yields a rich and wholesome milk. One of the most virulent of poisons, the Bohon Upas, is the concrete juice of Antiaris toxicaria of the Indian Archipelago. The Bread- fruit is the fleshy receptacle and multiple fruit of Artocarpus. Fustic is the wood of the South American Maclura tinctoria; the wood of our own Maclura or Osage Orange is used by the Western Indians for bows. The resin called Gum Lac exudes and forms small grains on the branches of the celebrated Banyan-tree (Ficus Indica, Fig. 142). 914. Subord. Mice® (True Nettle Family) ; which are herbs in colder countries, but often shrubs or trees in the tropics, with a watery juice, often with stinging hairs; the monoecious or dioecious flowers mostly loose, spicate, or panicled. Ovule orthotropous. Ovary always one-celled, and style or stigma one; the achenium usually surrounded by a dry and membranous calyx. Embryo straight, in fleshy albumen. — Ex. Urtica (the Nettle), &c. Innoc- uous plants, except for the stinging hairs of many species. The inner bark of Nettles yields very tough and slender fibres. 915. Sllbord. Caiinilbinc® (Hemp Family). Annual erect herbs, or perennial twining plants, with a watery juice and dioecious flow- ers ; the staminate flowers racemose or panicled; the pistillate glom- erate, or imbricated with bracts, and forming a kind of strobile-like ament; their calyx one-leaved. Stigmas two. Ovary one-celled, with an erect orthotropous ovule. Embryo coiled or bent: albumen none.—Ex. Cannabis (the Hemp), Humulus (the Hop). Hops are the catkins with large bracts; the bitter and sedative principle chiefly resides in the yellow grains that cohere to the scales and cover the fruit. The leaves of Hemp, when grown in a hot climate, are powerfully stimulant and narcotic, and are used in the East for intoxication. The inner bark is used for cordage, &c.476 ILLUSTRATIONS OF TIIE NATURAL ORDERS. 916. Ord. riataitilCeffi (Plane-tree Family) consists of the single genus Platflnus (Plane-tree, Button-ball), with one Asiatic and one or more North-American species: fine trees, with a watery juice, and alternate palmately-lobed leaves, with sheathing stipules. Flow- ers in globose amentaceous heads ; both kinds destitute of floral envelopes. Fruit a one-seeded club-shaped little nut, the base fur- nished with bristly hairs. Seed albuminous. 917. Ord. ,1II gland arete (Walnut Family). Trees, with alternate pinnated leaves, and no stipules. Flowers monoecious. Sterile flowers in aments, with a membranous irregular calyx, and indefinite stamens. Fertile flowers few, clustered, with the calyx adherent to the incompletely two- to four-celled but one-ovuled ovary, the limb small, three- to five-parted ; sometimes with as many small petals. Ovule orthotropous. Fruit drupaceous ; the exocarp fibrous-fleshy and coherent, or else coriaceous and dehiscent: endoearp bony. Seed four-lobed, without albumen. Embryo oily: cotyledons cor- rugate, two-cleft. — Ex. Juglans (Walnut, Butternut), Carya (Hick- ory, Pecan, &c.). — The greater part of the order is North Ameri- can. The timber is valuable; especially that of Black Walnut, for cabinet-work, and that of Hickory, for its great elasticity and strength. The young fruit is acrid: the seeds of several are de- licious ; those of the Walnut abound in a drying oil. 918. Ord. Clipulifera: (Oak Family). Trees or shrubs, with alter- nate and simple straight-veined leaves, and deciduous stipules. Flowers usually monoecious. Sterile flowers in aments, with a scale-like or regular calyx, and the stamens one to three times the number of its lobes. Fertile flowers solitary, two to three together, or in clusters, furnished with an involucre which encloses the fruit or forms a cupule at its base. Ovary adnate to the calyx, and crowned by its minute or obsolete limb, two- to six-celled with one or two pendulous ovules in each cell: but the fruit is a one-celled and one-seeded nut (Fig. 576). Seed without albumen. Embryo with thick and fleshy cotyledons, which are sometimes coalescent. — Ex. Quercus (the Oak), Fagus (the Beech), Corylus (the Hazel- nut), Castanea (the Chestnut), &c. Some of the principal forest- trees in northern temperate regions. The valuable timber and edible nuts they furnish are too well known to need enumeration. The astringent bark and leaves of the Oak abound in tannin, gallic acid, and a bitter extractive called Quercine ; they are used in tan- ning and dyeing. Quercitron is obtained from the Quercus tine-EXOGENOUS OR DICOTYLEDONOUS PLANTS. 477 toria. Galls are swellings on the leafstalks, &c., when wounded by- certain insects ; those of commerce are derived from Q. infectoria of Asia Minor. Cork is the exterior corky layer of the bark of the Spanish Quercus Suber. 919. Ord. Myricacete {Sweet-Gale Family). Shrubs, with, alter- nate and simple aromatic resinous-dotted leaves, monoecious or dioe- cious. Differs from the next principally by the one-celled ovary, with a single erect orthotropous ovule, and a drupe-like nut. — Ex. Myrica, Comptonia, the Sweet Fern. The drupes of M. cerifera (our Candleberry or Bayberry) yield a natural wax. 920. Ord. IktllltlCCtC {Birch Family). Trees or shrubs, with al- ternate and simple straight-veined leaves, and deciduous stipules. Flowers monoecious ; those of both kinds in aments (Fig; 312), and commonly achlamydeous, placed three together in the axil of each three-lobed bract. Stamens definite. Ovary two-celled, each cell with one suspended ovule: stydes or stigmas distinct. Fruit mem- branaceous or samara-like, one-celled and one-seeded, forming with the three-lobed bracts a kind of strobile. Albumen none. — Ex. Betula (the Birch), Alnus (Alder). The bark is sometimes astrin- FIG. 1164. Quercus Chinquapin in fruit: a, cluster of sterile aments. 1165. A magnified staminate flower. 1166. Transverse section of an ovary, showing the three cells with two> ovules in each. 1167. The immature seed, with the accompanying abortive ovule. 1168. The nut (acorn), in its scaly involucre, or cupule. 1169. Vertical section of the same, and of the included seed and embryo, showing the thick cotyledons. a478 ILLUSTRATIONS OF THE NATURAL ORDERS. gent, and that of the Birch is aromatic. The peculiar odor of Russia leather is said to be owing to a pyroligneous oil obtained from Betula alba, or White Birch. 1173 921. Ord. SalicacetB {Willow Family). Trees or shrubs, with al- ternate simple leaves, furnished with stipules. Flowers dicccious ; both kinds in aments, and destitute of floral envelopes (achlamyde- ous), one under each bract. Stamens two to several, sometimes monadelphous. Ovary one-celled, many-ovuled ! Styles or stigmas two, often two-cleft. Fruit a kind of follicle opening by two valves. Seeds numerous, ascending, furnished with a silky coma! Albu- men none. — Ex. Salix (Willow, Fig. 415-419), and Populus (the Poplar). Trees with light and soft wood: the slender, flexible shoots of several Willows are employed for wicker-work. The bark is bitter and tonic, and contains a peculiar substance (Salicine), which possesses febrifugal qualities. The buds of several Poplars exude a fragrant balsamic resin. FIG. 1170. Young ament of staminate flowers of a Birch (Betula fruticosa?). 1171. One of the three-lobed scales of the same, enlarged, showing the flowers (stamens) on the inner side. 1172. Ament of pistillate flowers. 1173. Branch in fruit. 1173'. One of the scales with its three flowers (pistils) seen from within. 1174. Magnified section of one of the two-celled pis- tils, displaying the ovule suspended from the summit of each cell. 1175. The pistils (with their subtending bract) in a more advanced state. 1176. Magnified cross-section of one of the ovaries. 1177. The mature fruit, with the cell divided vertically ; the single seed occupying the cavity ; a mere trace of the other cell being visible. 1178. The seed removed. 1179. The embryo.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 479 Subclass 2. Gymnospeiimous Exogenous Plants. ^ Ovules, and consequently tlie seeds, naked, that is, not enclosed in an ovary (560) ; the carpel being represented either by an open scale, as in Pines ; or by a more evident leaf, as in Cycas; or else wanting altogether, as in the Yew. 922. Ord. Conifer!® (Pine Family). Trees or shrubs, with branch- ing trunks, abounding in resinous juice (the wood chiefly consisting of a tissue somewhat intermediate between ordinary woody fibre and vessels, and marked with circular disks) ; the leaves mostly 1188 1186 1187 1180 1183 1181 1185 1184 evergreen, scattered or fascicled, usually rigid and needle-shaped or FIG. 1180. Carpellary scale of Cupressus sempervirens (the true Cypress), Seen from with- in, and showing the numerous orthotropous oyules that stand on its base. 1181. Branch of Abies Canadensis (Hemlock Spruce), with lateral etaminate flowers, and a fertile strobile. 1182. Staminate ament, magnified. 1183. Carpellary scale of a fertile ament, with its bract. 1184. Similar fertile scale, more magnified and seen from within; showing the two ovules ad- herent to its base: one of them (the left) laid open. 1185. The scale in front, nearly of the natural size, its inner surface occupied by the two seeds. 1186. Polycotyledonous embryos of Abies and Cypress. 1187. Vertical section of an embryo. 1188. Strobile of Taxodium dis- tichum (Suborder Cupressineae).480 ILLUSTRATIONS OP THE NATURAL ORDERS. linear, entire. Flowers monoecious or dioecious, commonly amenta- ceous. Staminate flowers consisting of one or more (often mona- delphous) stamens, destitute of calyx or corolla, arranged on a com- mon rhachis so as to form a kind of loose ament. — The particular structure of the flowers and fruit varies in the subordinate groups, chiefly as follows : — 923. Subord. Abietineae {Fir, or Pine Family proper). Fertile aments formed of imbricated scales ; which are the flat and open carpels, and bear a pair of ovules adherent to their base, with the foramen turned downwards (Fig. 511). Scales subtended by bracts. Fruit a strobile or cone (Fig. 596). Integument of the seed cori- aceous or woody, more or less firrhly adherent to the scale. Em- bryo in the axis of fleshy albumen, with two to fifteen cotyledons. Buds scaly. 924. Subord. Cupressineae (Cypress Family). Fertile aments of few scales crowded on a short axis, or more numerous and peltate, not bracteate. Ovules one, two, or several, borne on the base of the scale, erect (the foramen looking towards its apex, Fig. 516, 1180). Fruit an indurated strobile, or sometimes fleshy and with the scales concreted, forming a kind of drupe. Integument of the seed mem- branous or bony. Cotyledons two or more. Anthers of several parallel cells, placed under a shield-like connective. Buds naked. — Ex. Cupressus (Cypress), Taxodium (American Cypress), Juni- perus (Juniper, Red Cedar). 925. Subord. TaxinetC {Tew Family). Fertile flowers solitary, terminal, consisting merely of an ovule, forming a drupaceous or nut- like seed at maturity. There are, therefore, no strobiles and no earpellary scales. Embryo with two cotyledons. Buds scaly.— Ex. Taxus (the Yew), Torreya. 926. It is unnecessary to specify the important uses of this large and characteristic family, which comprises the most important tim- ber-trees of cold countries, and also furnishes resinous products of great importance, such as turpentine, resin, pitch, tar, Canada bal- sam, -&c. The terebintliine Juniper-berries are the fruit of Juni- perus communis. The Larch yields Venetian turpentine. The powerful and rubefacient Oil of Savin is derived from J. Sabina of Europe : for which our nearly allied J. Virginiana (Red Cedar) may be substituted. The leaves of the Yew are narcotic and dele- terious. The bark of Larch, and especially of the Hemlock-Spruce, is used for tanning.EXOGENOUS OR DICOTYLEDONOUS PLANTS. 481 927. Ord. Cycailaccffi (Cycas Family). Tropical plants, with an unbranched cylindrical trunk, increasing, like Palms, by a single terminal bud; the leaves pinnate and their segments more or less rolled up from the apex (circulate) in vernation, in the manner of Ferns. Flowers dkecious ; the staminate in a strobile or cone ; the pistillate also in strobiles, or else (in Cycas) occupying contracted and partly metamorphosed leaves; the naked ovules borne on its margins. — Ex. Cycas, Zamia.—-A kind of Arrowroot is obtained from these thickened stems, or caudexes, as from our dwarf Florida species (the Coontie of the aborigines) ; and a coarse Sago from the trunk of Cycas. FIG. 1189. Zamia integrifolia (the Coontie of Florida). 1190. Section of the sterile ament. 1191. One of its scales detached, bearing scattered anthers. 1192. Fertile ament, from which a quarter-section is removed. 1193. A pistillate flower, consisting of two ovules pendent from the thickened summit of the carpellary scale. 1194. A drupaceous seed, from which a part of the pulpy outer portion, at the apex, is removed. 1195. Vertical section through the seed (of the natural size), showing the pulpy outer coat, the hard inner integument, the albumen, and the embryo. 41482 ILLUSTRATIONS OF THE NATURAL ORDERS. Class II. Endogenous or Monocotyledonous Plants. Stem not distinguishable into bark, pith, and wood ; but the latter consisting of bundles of fibres and vessels irregularly imbeded in cellular tissue ; the rind firmly adherent; no medullary rays, and no appearance of concentric layers : increase in diameter effected by the deposition of new fibrous bundles, which at their commence- ment occupy the central part of the stem. Leaves seldom falling off by an articulation, sheathing at the base, usually alternate, entire, and with simple parallel veins (nerved). Floral envelopes when present mostly in threes, never in fives ; the calyx and corolla most commonly undistinguishable in texture and appearance. Embryo with a single cotyledon ; or, if the second is present, it is much smaller than the other, and alternate with it. Conspectus of the Orders. Gt'oup 1. Flowers on a spadix, furnished with a double and free perianth (answering to calyx and corolla). Ovary one- to three-celled, with a single ovule in each cell. Embryo in hard albumen.— Trees with unbranched columnar trunks. Palma:. Group 2. Flowers on a spadix ; with the perianth simple and free, or reduced to a few scales, or commonly altogether wanting. — Chiefly herbs. Terrestrial. Fruit nut-like, or comose, one-scedcd. Terrestrial, mostly with a spathe. Fruit baccate. Aquatic (floating or immersed). Flowers developed from the edge of the floating frond. Flowers axillary or on a spadix. Typhacea. Aracea:. Lemnace.e. Naiadaceas. Group 3. Flowers not spadiceous, furnished with a double and free perianth (calyx and corolla). Ovaries several, distinct, or sometimes united. Aquat- ic herbs. AlismackjE. Group 4. Flowers with a simple or double perianth, which is adherent to the ovary, regular, developed from a spathe, polygamous or diclinous. Ovary one-celled with parietal placentas, or 3 -9-celled. Seeds destitute of albu- men. — Aquatics. Hydrocharidaceas. Group 5. Flowers perfect with the double or 6-merous perianth adherent to the ovary (or more or less free in some Haanodoracca: and Bromeliacece). Seeds with albumen, except perhaps the very minute ones of Orchidaccte, &e. Leaves parallel-veined.ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 483 Stamens gynandrous, 1 or 2 fertile. Flower irregular. Stamens not gynandrous. Flower irregular. Fertile stamen 1, inferior. Fertile stamen 1, superior. Fertile stamens mostly 5, the sixth abortive. Stamens not gynandrous, regularly 3 or 6. Anthers extrorse. Stamens 3, before the sepals. Anthers introrse, when 3 before the inner perianth. Anther-cells separated by a broad connective. Anthcr-cells approximate or joined. Leaves not scurfy. Stems from bulbs. Leaves scurfy or woolly. No bulbs. Terrestrial. Stamens 3 or 6. Mostly epiphytes. Stamens 6. Orciiidace®. Zingiber ace.®. Cannace®, Musace®. Iridace®. Burmanniace®. Amaryllidace®. H®modorace®. Bromeliace®. Group 6. Flowers dioecious, with a 6-merous perianth adherent to the ovary. Seeds with a minute embryo in hard albumen. Leaves ribbed and netted- veined, articulated with the stem. Dioscoreace®. Group 7. Flowers dioecious or perfect; the regular perianth free from the ovary. Styles or sessile stigmas distinct. Embryo minute in hard albumen. Leaves more or less netted-veined. Smi lace®. Group 8. Flowers perfect, not from a spathe, with the regular 6-merous peri- anth free from the ovary. Seeds anatropous, with albumen. Perianth not glumaceous. Leaves parallel-veined. Anthers introrse. Styles united into one. Liliace®. Anthers extrorse. Styles mostly separate. Melanthace®. Perianth glumaceous. Styles united into one. Juncace®. Group 9. Flowers perfect, developed from a spathe, commonly somewhat ir- regular, the 6-merous perianth free from the ovary. Seeds anatropous, with albumen. Aquatics. Pontederiace®. Group 10. Flowers with a double or imbricated perianth, free from the ovary ; the exterior divisions (sepals) herbaceous or glumaceous; the inner (pet- als) petaloid, free from the one- to three-celled ovary. Seeds 2, 3, or many, orthotropous ; the embryo at the extremity of the albumen farthest from the hilum. Flowers perfect. Sepals herbaceous. Petals colored. Commelynace®. Flowers perfect, capitate. Sepals and bracts glumaceous. Xyridace®. Flowers monoecious or dioecious, capitate. Eriocaulonace®. Group 11. Flowers imbricated with glumaceous bracts (glumes), and disposed in sjnkelets ; the proper perianth none or rudimentary. Ovary one-celled, onc-ovuled. Seeds anatropous. Embryo at the extremity of the albumen next the hilum. Sheaths of the leaves closed. Glume or bract single. Cyperace®. Sheaths open. Glumes mostly in pairs. Gramine®.484 ILLUSTRATIONS OP THE NATURAL ORDERS. 928. Oi'd. Palma; (Palms). Chiefly trees, with unbranclied cylin- drical trunks growing by a terminal bud. Leaves large, clustered, fan-shaped or pinnated, plaited in vernation. Flowers small, per- fect or polygamous, mostly with a double (6-merous) perianth ; the stamens usually as many as the petals and sepals together. Ovary 1 -3-cellcd, with a single ovule in each cell. Fruit a drupe or berry. Seeds with a cartilaginous albumen, often hollow ; the embryo placed in a small separate cavity. — Ex. Palms, the most majestic race of plants within the tropics, and of the highest value to mankind, are scarcely found beyond the limits of these favored regions. The Date-tree (Phoenix dactylifera, the leaves of which are the Palms of Scripture), a native of Northern Africa, endures the climate of the opposite shores of the Mediterranean: while in the New World, Chamaerops Palmetto (Fig. 184), the only arborescent species of the United States, and one or two low Palms with a creeping caudex (Dwarf Palmetto), extend from Florida to North Carolina. Palms afford food and raiment, wine, oil, wax, flour, sugar, salt, thread, weapons, utensils, and habitations. The Cocoanut (Cocos nucifera) is perhaps the most important, as well as the most widely diffused species. Besides its well-known fruit, and the beverage it contains, 1200 1201 1202 1197 1196 1198 1199 1203 the hard trunks are employed in the construction of huts; the ter- minal bud (as in our Palmetto and other Cabbage Palms) is a deli- cious article of food; the leaves are used for thatching, for making FIG. 1196. Branch of the inflorescence of Chamaerops hystrix (Blue Palmetto). 1197- A sterile flower. 1198. Perfect flower, with the calyx and corolla removed. 1199. Same, with three of the stamens removed, so as more distinctly to show the three somewhat united carpels. 1200. One of the carpels enlarged, seen laterally. 1201. Same, with a section of its inner face, showing the ovule or young seed. 1202. Vertical section of a young cocoanut, showing the hollow albumen; and also the small embryo in a separate little cavity. 1203. Section of a Palm-stem.ENDOGENOUS OK MONOCOTYI.EDONOUS PLANTS. 485 bats, baskets, mats, fences, for torches, and for writing upon ; the stalk and midrib for oars ; their ashes yield abundance of potash ; the juice of the flowers and stems (replete with sugar, which is sometimes separated under the name of Jcigery) is fermented into a kind of wine, or distilled into Arrack; from its spatlies (as from some other Palms), when wounded, flows a grateful laxative bever- age, known in India by the name of Toddy; the rind of the fruit is used for culinary vessels ; its tough, fibrous, outer portion is made into very strong cordage (Coir rope) ; and an excellent fixed oil is copiously expressed from the kernel. Sago is procured from the trunks of many Palms, but chiefly from species of Sagus of Eastern India. Canes and Rattans are the slender, often prostrate, stems of species of Calamus. — The Phytelephas, or so-called Ivory Palm, of Central America, the seeds of which are the Vegetable Ivory now so commonly used by the turner, in place of ivory, for small articles, is not a genuine Palm, having polygamo-dicecious flowers with a rudimentary perianth, or none at all, &c. It is proposed as the type of an order (Piiytelephante^e) ; but may for the present be ap- pended to the Palms ; between which and the succeeding orders stands the 929. Ord. Pandanacetc ; tropical arborescent plants, of Palm-like port, but their simplified diclinous flowers destitute of a perianth, the one-celled ovary many-ovuled. The seeds of Pandanus (the Screw- Pine, Fig. 140), &c. are eatable. From the. young leaves of Car-I ludovica the famous Panama hats are braided. 930. Ord. TyphaceBB (the Cat-tail Family) consists of two genera; namely, Typha (the Cat-tail), and Sparganium (Bur-reed), of no important use. They are spadiceous plants with excessively re- duced flowers, having no perianth. 931. Ord. jlrilCCiT (Arum Family). Herbs, with a fleshy corm or rhizoma, often shrubby or climbing plants in the tropics; the leaves sometimes compound or divided, commonly netted-veined. Flowers mostly on a spadix (often naked at the extremity), usually surround- ed by a spathe or hood (Fig. 313, 314). Flowers commonly monoe- cious, and destitute of envelopes, or with a single perianth. Ovary one- to several-celled, with one or more ovules. Fruit a berry. Seeds with or without albumen.-—Ex. Arum, Calla, Symplocarpus (Skunk-Cabbage), Orontium, Acorus (Sweet Flag) : the three latter bear flowers furnished with a perianth. — All are endowed with an acrid volatile principle, which is merely pungent and aromatic in 41*486 ILLUSTRATIONS OP THE NATURAL ORDERS. Sweet Flag (Acorus Calamus), but extremely sharp in Arum, Indian Turnip, &c. The acrid principle of these plants is volatile, and is dissipated by heat or in drying. When cooked, their farina- ceous corms are eatable. That of Taro of the South Sea Islands, and some other species of Colocasia, are important articles of food. Symplocarpus foetida exhales a strong odor, very like that of the 1210 1211 1209 skunk, whence, as it has large and roundish leaves in a radical clus- ter, it is called Skunk Cabbage. The roots have been used in medi- cine as an antispasmodic. 932. Ot'd. Lemnaccie (Duckweed Family), consisting chiefly of Lemma (Duckweed or Water Flax-seed) ; floating plants, with then- roots (if any) arising from the bottom of a flat frond, and hanging loose in the water ; their flowers produced from the margin of the frond, bursting through a membranous spathe; the sterile, of one or FIG. 1204. Young leaf, and 1205, spathes and flowers, of Symplocarpus foetida. 1206. A separate flower when young. 1207. A detached sepal and stamen seen from within 1208. An anther seen from the front. 1209. The spadix or collective head in fruit; a quarter-section removed, showing sections of the immersed seeds. 1210 A seed detached, of the natural size. 1211. Section of the seed, with its large globular embryo and plumule : in this plant there is no albumen.ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 487 two stamens ; the fertile, of a one-celled ovary; in fruit a utricle: they are a kind of minute and greatly reduced Araceoe, connecting that order with the next. 1214 1212 1213 1219 1216 1217 1219 933. Ord. NaiadaceSB (Pondweed Family). Water-plants, with cellular leaves, and sheathing stipules or bases: the flowers incon- spicuous, sometimes perfect. Perianth simple and scale-like, or none. Stamens definite. Ovaries solitary, or two to four and dis- tinct, one-seeded. Albumen none. Embryo straight or curved. — Ex. Potamogeton (Pondweed), Najas, Ruppia, Zostera ; the two latter in salt or brackish water. 934. Ord. Alismacctc ( Water-Plantain Family). Marsh herbs, with the leaves and scapes usually arising from a creeping rhizoma; the former either linear, or bearing a flat limb, which is ribbed or nerved, but the veinlets commonly reticulated. Flowers regular, perfect or polygamous, mostly in racemes or panicles, not on a spa- dix. Perianth double, the three petals commonly different from the sepals, so as evidently to represent a calyx and a corolla. Seeds soli- tary in each carpel or cell, straight or curved, destitute of albumen. — Ex. Alisma (Water-Plantain), Sagittaria (Arrowhead); belong- ing to the proper Alisma Family, which has the seed (and conse- PIG. 1212. Whole plant of Lemna minor, magnified, bearing a staminate monandrous flow- er. 1213. An individual with a diandrous perfect flower ; which at 1214 is seen separate, with its spathe, highly magnified. 1215. Flower of Lemna gibba, much magnified. 1216. Vertical highly magnified section of the pistil and the contained ovule of Lemna minor 1217 The fruit, and 1218, its section, showing the seed. 1219. Section through the highly magnified seed and large embryo.488 ILLUSTRATIONS OR THE NATURAL ORDERS. quently the embryo) curved or doubled upon itself. Triglochin and Scheuchzeria chiefly constitute the suborder Juncagineac ; where the seed and embryo are straight, and the petals (if present) are greenish like the calyx. Slightly acrid plants, and some of them astringent, 1221 1222 1223 1232 1230 935. Ord. lllllninatCir, represented by Butomus, the Flowering- Bush of Europe, and three small tropical genera, is a form of the last with many ovules attached to the whole face of the carpels: these are separate or combined. Some have a milky juice. 936. Ord. llydrocharidaceffi (Frog’s-bit Family) consists of a few aquatic herbs, with dioecious or polygamous regular flowers on scape- like peduncles from a spathe, and simple or double floral envelopes, which in the fertile flowers are united in a tube, and adnate to the 1 - 6-celled ovary, more commonly one-celled with three parietal placentas. Seeds numerous, without albumen. — Ex. Limnobium, Vallisneria, Anacharis. 937. Ord. OrchidiirciC (Orchis Family). Herbs, of varied aspect and form; distinguished from the other orders with an adnate ovary, and from all other plants, by their irregular flowers, with a perianth FIG 1220. Raceme or spike of Triglochin palustre. 1221. Enlarged flower. 1222. A petal and stamen. 1223. The club-shaped capsule. 1224. A magnified seed, exhibiting the rhaphe and chalaza. 1225. Embryo of the same. 1226. Vertical section of the same, bringing the plumule to view. 1227. Cros9-section (more magnified), showing the cotyledon wrapped around the plumule. FIG. 1228. Leaf, and 1229, flower, of Alisma Plantago 1230. More enlarged flower, with the petals removed. 1231. Carpel, with the ovary divided, showing the doubled ovule. 1232. Vertical section of the germinating seed of Alisma Damasonium; a, the cotyledon ; 6, the plu- mule ; c, the protruding radicle.ENDOGENOUS OK MONOCOTYLEDONOUS PLANTS. 489 of six parts ; their single fertile stamen (or in Cypripedium their two stamens) coherent with the style (composing the column) ; their pollen usually combined into two or more granular or waxy masses (pollinia) ; the ovary one-celled, with three parietal placentae, 1235 1233 1234 1236 covered with numerous minute seeds. —Ex. Orchis, Cypripedium (Ladies’ Slipper), Arethusa, &c. In the tropics many are Epiphytes (149, Fig. 144). Many are cultivated for their beauty and singu- larity. The tuberiferous roots are often filled with a very dense mucilaginous or glutinous substance (as those of our Aplectrum, thence called Putty-root). Of this nature is the Salep of commerce, the produce of some unascertained species of Middle Asia. The fragrant Vanilla is the fleshy fruit of Vanilla planifolia and other tropical American species. The roots of Cypripedium are used as a substitute for Valerian. 938. Ord. Zingibcraccs (Ginger Family) consists of some mostly showy tropical aromatic herbs, the nerves of their leaves diverging FIG. 1233. Orchis spectabilis : a, a separate flower. 1234. Column (somewhat magnified), from which the other parts are cut away: the two anther-cells opening and showing the pollen- masses. 1235. Magnified pollen-mass, with its stalk. 1236. Arethusa bulbosa. 1237. The column, enlarged: the anther terminal and opening by a lid. 1238. Magnified anther, with the lid removed, showing the two pollen-masses in each cell.490 ILLUSTRATIONS OF THE NATURAL ORDERS. from a midrib ; the adnate perianth irregular and triple (having a corolla of two series as well as a calyx) ; fertile stamen one, on the anterior side of the flower, free ; the fruit a three-celled capsule or berry; the seeds several: with the embryo in a little sac at one extremity of the farinaceous albumen. — There are, in fact, six stamens in the androecium, the three exterior petaloid and forming the so-called inner corolla, and two of the inner verticel are sterile. — Their properties and economical uses are well represented by the pungent aromatic rootstock of Ginger (Zingiber officinale), Galin- gale (Alpinia Galanga, &c.), the seeds of Cardamon, &c. The same cordial qualities in lesser degree exist in the roots of Curcuma longa, &c. which furnish the coloring matter called Turmeric ; while other species yield starch, like the closely allied 939. Ord. CannacetE {Arrowroot Family), which also consists of trop- ical plants, differs from the preceding chiefly in the want of aroma, and in having the single fertile stamen posterior, with a one-celled anther. —- Ex. Maranta arundinacea, which yields the Arrowroot of the. West Indies ; the tubers of which are filled with starch. 940. Ol‘d. Musacea (Banana Family). Tropical plants, of which the Banana and Plantain are the type; distinguished by their simple perianth and five or six perfect stamens. The fruit is an important staple of food in the tropics; the gigantic leaves are used in thatching; and the fibres of Musa textilis yield Manilla hemp, as well as a finer fibre from which some of the most delicate India mus- lins are made. 941. Ord. Bnrmanniace® consists of small, mostly tropical, annual herbs, commonly with a one-celled ovary and three parietal placentas, (but in several the ovary is three-celled); differing from Orehidaceas by their regular flowers with three stamens ; and from Iridaceas by the position of these before the inner divisions of the perianth, the introrse anthers, &c.•—-Ex. Burmannia and Apteria, of the South- ern States. 942. Ord. Iridacctc (/m Family). Perennial herbs ; the floiver- stems springing from bulbs, conns, or rhizomas, rarely with fibrous roots, mostly with equitant leaves. Flowers regular or irregular, showy, often springing from a spathe. Perianth with the tube ad- herent to the three-celled ovary, and usually elongated above it; the limb six-parted, in two series. Stamens three, distinct or monadel- phous ; the anthers extrorse! Stigmas three, dilated or petaloid! Seeds with hard albumen. — Ex. Iris, Crocus. The rootstocks,ENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 491 corms, &c. contain starch, with some volatile acrid matter. Those of Iris cristata are very pungent; those of I. versicolor, &c. are drastic. Orris-root is the dried rhizoma of Iris florentinn, of South- ern Europe. The true Saffron consists of the dried orange-colored stigmas of Crocus sativus. 943. Ol'd. Amaryllidaceaj (Amaryllis Family). Bulbous plants (sometimes with fibrous roots), bearing showy flowers mostly on scapes. Perianth regular, or nearly so; the tube adherent to the ovary, and often produced above it, six-parted. Stamens six, dis- tinct, with introrse anthers. Stigma undivided or three-lobed. Fruit a three-celled capsule or berry. Seeds with fleshy albumen. — Ex. Amaryllis, Narcissus, Crinum, &c.; mostly ornamental plants. The bulbs acrid, emetic, &c.: those of Hoemanthus (with whose juice the Hottentots poison their arrows) are extremely venomous. The fermented juice of Agave is the intoxicating Pulque of the Mexicans. Hypoxys, which has been taken as the type of an order, may prop- erly be referred to this family. FIG. 1239. Iris cristata. 1240. The summit of the style, petaloid stigmas, and stamens. 1241. Vertical section of the ovary (the equitant leaves cut away) and long tube of the peri- anth. 1242. Cross-section of the pod. 1243. Seed. 1244. Enlarged section of the same, show- ing the embryo, &c.492 ILLUSTRATIONS OF THE NATURAL ORDERS. 944. Ord. Bromeliacca: (Pine-Apple Family) consists of American and chiefly tropical plants ; with rigid and dry channelled leaves, often with a scurfy surface, a mostly adnate perianth of three sepals and thr.ee petals, and six or more stamens ; the seeds with mealy albumen. — Ex. Ananassa, the Pine-Apple ; the fine fruit of which is formed by the consolidation of the imperfect flowers, bracts, and receptacle into a succulent mass. Tillandsia, the Black Moss or Long Moss (which, like most Bromelias, grows on the trunks and branches of trees in the warmer and humid parts of America), has the ovary free from the perianth. 945. Ot'd. Htcmodoi'acese (Bloodwort Family) is composed of peren- nial herbs, with fibrous roots, equitant or ensiform leaves ; which, with the stems and flowers, are commonly densely clothed with woolly hairs or scurf. Perianth with the tube either nearly free from, or commonly adherent to, the three-celled ovary; the limb six-cleft, regular. Stamens six, or only three, with introrse anthers. Style single, the stigma standing over the dissepiments of the ovary. Embryo in cartilaginous albumen. — Ex. Lachnanthes (Red-Root), Lophiola. — Some have a red juice. The roots are astringent and tonic, especially in Aletris. 946. Ord. Dioscoreamc (Yam Family) consists of a few twining plants, with large tuberous roots or knotted rootstocks ; distinguished among Endogens by their ribbed and netted-veined leaves, with dis- tinct petioles, and by their inconspicuous dioecious flowers, with the perianth in the pistillate flowers adherent to the ovary; the limb six-cleft in two series. Stamens six. Ovary three-celled, with only one or two ovules in each cell: styles nearly distinct. Fruit often a three-winged capsule. Albumen cartilaginous. — Ex. Dioscorea. The tubers of one or or more species, filled with starch and mucilage (but more or less acrid until cooked), are Yams, an important article of food in tropical countries. 947. fil’d. Smilncctc (Smilax Family) is also remarkable among Endogens for netted-veined leaves. It consists both of herbs and of shrubby plants climbing by tendrils; the perianth is free from the ovary; the mostly three styles or sessile stigmas are entirely dis- tinct; the anthers are introrse; and the fruit tfc a berry. Embryo minute, in hard albumen. — In the True Smilax Family, the flowers are dioecious and axillary; the six divisions of the perianth are alike; the anthers are one-celled, and the few seeds are orthotropous and pendulous. They are mostly shrubby and alternate-leavedENDOGENOUS OH MONOCOTYLEDONOUS PLANTS. 493 plants. Ex. Smilax (Greenbrier, &c.) ; far the most important species is S. officinalis of tropical America, the rootstocks of which are the officinal Sarsaparilla. 948. Subord. Trilliace* (Trillium Family) consists of low herbs, with whorled leaves and per- fect flowers, which in the largest genus, Trillium, have a green calyx and a colored corolla; the anthers are two-celled ; the seeds anatropous and rather numerous. — The short rootstock of Trillium (Fig. 169), called Birthroot, has a place in the popular materia medica ; but it is doubtful if it really possesses any useful properties. 949. Ord. Liliace® (Lily Family). Herbs, with the flower-stems springing from bulbs, tubers, or with fibrous or fascicled roots. Leaves simple, sheathing or clasping at the base, parallel-veined. Flowers regular, per- fect. Perianth colored, mostly of six parts, or six-cleft. Stamens six: anthers introrse. Ovary free, three-celled: the styles united into one. Fruit capsular or baccate, with several or numerous seeds in each cell. Albumen fleshy. — This large and widely diffused order comprises a great variety of forms: the Lily,*Dog-tooth Violet, and Tulip represent one division; the Tuberose, a second; the Aloe and Yucca, a third; the Hyacinth, the Onion, Leek, and Garlic (Allium), and the As- phodel, a fourth; the Asparagus, Lily of the Valley, and Solomon’s Seal, a fifth, which is nearly allied to the order Smilacese. Acrid and often bitter principles prevail in the order, and are most concen- trated in the bulbs, &c., which abound in starchy or mucilaginous matter, and are often edible when cooked. Squills are the bulbs of Scilla maritima of the South of Europe. Aloes is the acrid and bitter inspissated juice of the succulent leaves of species of Aloe. The original Dragon’s-blood was derived from the juice of the fa- mous Dragon-tree (Dracaena Draco) of the East. — The leaves of Phormium tenax yield the New Zealand hemp, one of the FIGr. 1245. A flower of Trillium erectum; a front view, 1246. A diagram of the game. 42494 ILLUSTRATIONS OF THE NATURAL ORDERS. strongest vegetable fibres known. Many are the ornaments of our gardens and conservatories. 950. Ord. Melanthace® (Golchicum Family). Herbs, with bulbs, icorms, or fasciculated roots. Perianth regular, in a double series ; the sepals and petals either distinct, or united below into a tube. Stamens six, with extrorse anthers (except in Tofieldia and Pleea). Ovary free, three-celled, several-seeded : styles distinct. Albumes, fleshy. The true Melanthacese, or 951. Subord. Melanthiea; have a mostly septicidal capsule and a marcescent or persistent perianth. — Ex. Colchicum has a perianth with a long tube, arising from a subterranean ovary; it is also re- markable for flowering in the autumn, when it is leafless, ripening its fruit and producing its leaves the following spring. In most of the order, the leaves of the perianth are uncombined; as in Vera- trum (White Hellebore), Ilelonias, &c. Acrid and drastic poison- ous plants, with more or less narcotic qualities ; chiefly due to a peculiar alkaloid principle, named Veratria, which is largely ex- FIG. 1247. Erythronium Americanum (Dog-tooth Violet, Adder’s-tongue). 1248. The bulb. 1249. Perianth laid open, with the stamens. 1250. The Pistil. 1251. Cross-section of the capsule.ENDOGENOUS OR MONOCOTYLRDONOUS PLANTS. 495 traded from the seeds of Sabadilla, or Cebadilla; the produce of Schcenocaulon officinale, &c. of the Mexican Andes. The seeds and the corms of Colchicum are used in medicine. 1255 cidal capsule or berry, more or less united styles, and a deciduous perianth ; the stems from rootstocks. — Ex. Uvularia. 953. Ord. Juncace® (Rush Family). Herbaceous, mostly grass- like plants, often leafless; the small glumaceous flowers in clusters, cymes, or heads. Perianth mostly dry, greenish or brownish, of six leaves (sepals and petals) in two series. Stamens six, or three: anthers introrse. Ovary free, three-celled, or one-celled from the placenta not reaching the axis ; their styles united into one: stig- mas three. Capsule three-valved, few- or many-seeded. Albumen fleshy. — Ex. Juncus (Rush). 954. Ol’d. Poiltederiacc® (Pickerel-weed Family) comprises a few aquatic plants, with the flowers, either solitary or spicate, arising from a spathe or from a fissure of the petiole; the six-cleft and colored perianth insistent and withering, often adherent to the base of the three-celled ovary; the stamens three, and inserted on the FIG. 1252. Colchicum autumnale ; a flowering plant*. 1253 Perianth laid open. 1254. Pistil, with the long distinct styles. 1255 Leafy stem and fruit (capsule opening by septi- cidal dehiscence). 1256. Capsule divided transversely. 1257. Section of a seed, and a sep- arate embryo.496 ILLUSTRATIONS OP THE NATURAL ORDERS. throat of the perianth, or six, and unequal in situation. Ovules anatropous, numerous; but the fruit often one-celled and one-seeded. — Ex. Pontederia (Pickerel-weed), Ileteranthera, &c. 955. Ord. CoinmelynaceBE (Spiderwort Family), with usually sheath- ing leaves; distinguished from other Endogens (except Alismace® and Trillium) by the manifest distinction between the calyx and corolla; the former of three herbaceous sepals; the latter of as many delicate colored petals. Stamens six, or fewer: anthers with two separated cells: filaments often clothed with jointed hairs, hypogynous. Ovary two- or three-celled: styles united into one. Capsule few-seeded, loculicidal. Seeds orthotropous. Embryo small, pulley-shaped, partly sunk in the apex of the albumen.— Ex. Commelyna, Tradescantia (Spiderwort) Mucilaginous plants. 956. Ord. XyridaceiE. Low, rush-like plants; with ensiform, grassy or filiform radical leaves, sheathing the base of a simple scape, which bears a head of flowers at the apex, imbricated with bracts. Calyx of three glumaceous sepals, caducous. Petals three, with claws, more or less united into a monopetalous tube. Stamens six, inserted on the corolla ; three of them bearing extrorse anthers, the others mere sterile filaments. Ovary one-celled, with three parietal placenta’, or three-celled: styles partly united: stigmas lobed. Capsule many-seeded. Seeds orthotropous, albuminous. — Ex. Xyris (Yellow-eyed Grass). 957. Ol’d. Eriocaulonacete (Pipewort Family). Aquatic or marsh herbs, with much the structure of the preceding; their leaves cel- lular or fleshy ; their minute flowers (monoecious or dioecious) crowded, along -with scales or hairs, into a very compact head : the corolla less petaloid than in Xyridace®; the six stamens often all perfect; the ovules and seeds solitary in each cell. —Ex. Eriocaulon. 958. Ord. ResliacetE consists of South African and Australian Rush-like plants, with the aspect of Cyperace®, but with one-celled anthers and orthotropous seeds. 959. Ol’d. Cyperace® (Sedge Family). Stems {culms) usually solid, c®spitose. Sheaths of the leaves closed. Flowers one in the axil of each glumaceous bract. Perianth none, or a few bristles. Stamens mostly three, hypogynous. Styles two or three, more or less united. Fruit an achenium. Embryo small, at the extremity of the seed next the hilum. — Ex. Cyperus, Scirpus, Carex (Sedges). The herbage is little eaten by cattle. Some Clubrushes are used for making mats, chair-bottoms, &c. The papyrus of the EgyptiansENDOGENOUS OR MONOCOTYLEDONOUS PLANTS. 497 was made from the stems of Cypems Papyrus. The tubers of C. esculentus are sweet and edible, but are too small to be of much value for food. 1262 960. Ord. Gramincse (Grass Family). Stems (culms) cylindrical, mostly hollow, and closed at the nodes. Sheaths of the leaves split or open. Flowers in little spikelets, consisting of two-ranked imbri- cated bracts ; of which the exterior are called glumes, and the two that immediately enclose each dower, paleae. Perianth none, or in the form of very small and membranous hypogynous scales, from one to three in number, distinct or united (termed squamulce, squa- mellce, or lodicidce). Stamens commonly tliree: anthers versatile. Styles or stigmas two; the latter feathery. Fruit a caiyopsis. Embryo situated on the outside of the farinaceous albumen, next the FIG. 1258. Scirpus triqueter, with its cluster of spikelets. 1259. A separate flower, en- larged. showing its rudimentary perianth of a few denticulate bristles, its three stamens, and pistil with a three-cleft style: a, section of the seed, showing the minute embryo. 1260. Ca- rex Carey ana, reduced in size (flowers monoecious, the two kindB in different spikes). 1261. Stem, with the staminate and upper pistillate spike, of the size of nature. 1262. A scale of the staminate spike, with the flower (consisting merely of three stamens) in its axil. 1263. Magnified pistillate flower, with its scale or bract: the ovary enclosed in a kind of sac (perigy- nium), formed by the union of two bractiets. 1264. Cross-section of the perigynium; with the pistil, p, removed. 1265. Vertical section of the achenium, showing the seed. 42*498 ILLUSTRATIONS OF THE NATURAL ORDERS. liilura (Fig. 126-128,622-624). — Ex. Agrostis, Phleum, Poa, Festuca, which are the principal meadow and pasture grasses: Ory- za (Rice), Zea (Maize), Avena (the Oat), Triticum (Wheat), Secale (Rye), Hordeum (Barley), are the chief cereal plants, cultivated for their farinaceous seeds. This universally diffused order is one of the largest of the vegetable kingdom, and doubtless the most impor- tant ; the floury albumen of the seeds and the nutritious herbage constituting the chief support of man and the herbivorous animals. No unwholesome properties are known in the family except in the grain of Darnel, which is deleterious. Ergot, or Spurred Rye, is no exception, being a morbid growth, caused by a parasitic fungus. The stems of grasses frequently contain sugar in considerable quan- tity (especially when they are solid); as in Maize, the sweet variety of Sorghum vulgare, or Broom-Corn, and in Sugar-Cane (Saccharum officinarum), which affords the principal supply of this article. 1271 1275 1276 1277 1278 1280 1273 FIG. 1266. One-flowered spikelet or locusta of Alopecurus, with the glumes separated. 1267. Same, with the glumes removed: an awn on the hack of the outer palea. 1268. One- flowered spikelet of an Agrostis. 1269. Pistil of a Grass, showing the two feathery stigmas, and the two hypogynous scales or squamulce, larger than usual (representing the perianth). 1270. Two-flowered spikelet of an Avena ; with the glumes spreading. 1271. One of the flow- ers with its paleae ; the exterior pointed, with two bristles or cusps at the apex, and with a bent awn on the back. 1272. Many-flowered spikelet of Glyceria fluitans. 1273. An enlarged separate flower of the same, seen from within, showing the inner palese, &c. 1274. The fruit (caryopsis) of the Wheat, with an oblique section through the integuments of the embryo, which is exterior to the albumen. 1275. Detached magnified embryo : a. the imperfect cotyle- don ; 6, the first leaf of the plumule ; c, the second leaf of the plumule ; cf, the radicle. 1276. The caryopsis of Hordeum (Barley). 1277. A cross-section. 1278. A vertical section, show- ing the external embryo at the base. 1279. Magnified detached embryo, with its broad cotyle- don and the plumule. 1280. More magnified vertical section of the same: a, the plumule ; 6, the radicle.CRYPTOGAMOUS OR FLOWERLESS PLANTS. 499 Series II. Cryptogamous or Flowerless Plants. Plants destitute of proper flowers (stamens and pistils), and propagated by spores instead of seeds. Class III. Acrogenous Plants.* Vegetables with a distinct axis, growing from the apex, with no provision for subsequent increase in diameter (containing woody and vascular tissue), and usually with distinct foliage. 961. On!. EquisetacetC (Horsetail Family). Leafless plants; with striated, jointed, simple or IS8a 128l branched stems (containing ducts and some spiral vessels), which are hollow and closed at the joints ; each joint terminating in a toothed sheath, which surrounds the base of the one above it. In- florescence consisting of peltate scales crowded in a terminal spike, or kind of strobile: each with several theca attached to its lower surface, longitudinally de- hiscent. Spores numerous, with four elastic club-shaped bodies (of unknown use), wrapped around them when moist, or spreading when dry. — Ex. Equi- setum. The epidermis of Equi- setum hyemale (the well-known Scouring Rush) contains so much silex that it is used for polishing. * For illustrations of Classes III. and IV. see the plates of Manual of the Botany of the Northern United States. FIG. 1281. Summit of the stem of Equisetum sylvaticum. 1282. Part of the axis of the fructification, with some of the fruit-bearing organs, shown magnified in Fig. 1283, a view from underneath. 1284. A separate theca, or spore-case, more magnified. 1285; 1286. Spores, with the club-shaped appendages more magnified.500 ILLUSTRATIONS OP THE NATURAL ORDERS. 962. Ord. Filices {Ferns). Leafy plants ; with the leaves (fronds') spirally rolled up or circinate in vernation (except in one suborder), usually rising from prostrate or subterranean rootstocks, or in tree- Ferns from an erect arborescent trunk (Fig. 100), and bearing on the veins of their lower surface, or along the margins, the simple fructification, which consists of one-celled spore-cases (theca or spo- rangia), opening in various ways, and discharging the numerous 1292 1293 1288 minute spores. The stalk or petiole of the frond is termed a stipe. — There are four principal suborders, viz.: — FIG. 1287. Camptoaorus rhizophyllus (Walking Fern); the fronds rooting, as they fre- quently do, at the apex; the sori occupying the reticulated veins on the back. 1288. Division (pinnula) of a frond of Aspidium Goldianum ; the roundish sori attached to the simple veins, and covered with an indusium, which is fastened in the centre, and opens all around the mar- gin. 1289. Magnified sporangium of this division of Ferns, with its stalk, and elastic ring partly surrounding it; which, tending to straighten itself when dry, tears open the sporangium, shedding the minute spores (1290). 1291. Schizaea pusilla of about the natural size, with simple and slender radical leaves ; the contracted fertile frond pinnate. 1292. A division (pinna) of the fertile frond, magnified, showing the sessile sporangia occupying its lower surface. 1293. One of the sporangia more magnified; they have no proper ring, and open by a longitudinal eleft. 1294. Ophioglossum vulgatum (Adder’s-tongue); the sporangia forming a two-ranked spike on a transformed and contracted frond: «, portion of the spike enlarged, showing the co- riaceous sporangia, destitute of a ring, and opening transversely.CRYPTOGAMOUS OR FLOWERLESS PLANTS. 501 963. Sllboi'd. PolypodineiE. Sporangia collected in dots, lines, or variously shaped clusters (son or fruit-dots) on the back or margins of the frond or its divisions, or rarely covering the whole surface, stalked, cellular-reticulated, the stalk running into a vertical incom- plete ring, which by straightening at maturity ruptures the sporan- gium transversely on the inner side, discharging the spores. Fruit- dots often covered, at least when young, by a membrane called the involucre, or more properly the indusium. 964. Subord. llymenophylleEB. Sporangia borne on a vein extended beyond the margin of the frond into a setiform receptacle, sessile, and surrounded by a horizontal complete ring ; otherwise as in the last. — Ex. Hymenophyllum, Trichomanes. Ferns of very delicate texture, chiefly tropical. 965. Subord. Osmundincsc. Sporangia variously collected, cellular- reticulated, destitute of any ring (as in Osmunda or Flowering Fern), or with an imperfect trans- verse ring around the top (as in Scluzam, Fig. 1293), opening lengthwise by a regular slit. 966. Subord. Ophioglossctc. Spo- rangia spiked, closely sessile, naked, coriaceous and opaque, not reticu- lated, destitute of a ring, opening by a transverse slit into two valves, discharging the very copious spores which appear like floury dust. Fronds straight, never rolled up (or circinate) in the bud ! 967. Ord. Lycopodiacetc (Club-Moss Family). Plants with creeping or erect leafy stems, mostly branching; the crowded leaves lanceolate or subulate, one-nerved. Sporangia single and sessile in the axils of the leaves, sometimes all crowded at the summit under leaves which are changed into bracts and form FIG. 1295. Lycopodium Carolinianum, of the natural size. 1296. A leaf from the spike of. fructification, with the spore-case in its axil, and spores falling out. 1297. A group of four larger spores (oophoridia) of Selaginella, magnified. 1298. The same, separated. 1299. A burst spore-case of Selaginella apus, with its four large spores. 1296502 ILLUSTRATIONS OF THE NATURAL ORDERS. a kind of ament, one-celled, or rarely two- to three-celled, dehiscent, containing either minute grains, appearing like fine powder, or a few rather large sporules ; both kinds often found in the same plant. — Ex. Lycopodium (Club-Moss, Ground Pine), Selaginella.—Append- ed to this family, rather than to the next (with which it has gener- ally been associated), is the 968. Sllboi'd. Isoeti note (Quillwort Family), consisting of a few acaulescent submersed aquatics, with their sporangia in the axils and immersed in the inflated base of the grassy subulate leaves. — Ex. Isoetes. 969. Ol'd. Ilydropterides. Aquatic or marshy cryptogamous plants, of diverse habit, with the fructification borne at the bases of the leaves, or on submerged branches: this consists of two sorts of or- gans, contained in indehiscent or irregularly bursting involucres (sporocarps). It comprises the 970. Sllboi'd. MarsilatCtC (Pepperwort Family) ; with creeping stems; the leaves long-stalked, circinate in vernation, and of four obeordate leaflets in Marsilea, or filiform and destitute of leaflets in Pilularia (the Pillwort). 971. Sllbord. Salvinieie ; which are free floating plants, with alter- nate and sometimes imbricated sessile leaves ; the fructification borne on the stem or branches underneath. — Ex. Salvinia, Azolla. (For illustrations, see Manual of Botany, Plate 14.) Class IV. Anophytes. Vegetables composed of parenchyma alone, with acrogenous growth, usually with distinct foliage, sometimes the stem and foliage confluent into a frond. 972. Ord. Musci (Mosses). Low, tufted plants, always with a stem and distinct (sessile) leaves, producing spore-cases which mostly open by a terminal lid, and contain innumerable simple spores. The fertilizing organs, or antheridia, have been elsewhere mentioned. In Mosses these accompany the pistillidia; the latter develop into the capsule, or more properly the sporangium or spore-case. This is rarely (in Andrnea) dehiscent into four valves, or irregularly rup- tured (in Phascum, &c.). It usually opens by a lid (operculum) : beneath the lid and arising from the mouth of the capsule are com- monly either one or two rows of rigid processes (collectively theCRYPTO GAMOUS OR FLOWERLESS PLANTS. 503 peristome), which are always some, multiple of four: those of the outer row are called teeth, of the inner, cilia. The spores which fill the cavity commonly appear like an impalpable greenish powder. The pedicel continued through the capsule forms the columella: en- larged under the capsule it sometimes forms an apophysis. The 1303 130S 1313 1311 calyptra separating early at its base is carried up on the apex of the capsule ; if it splits on one side, it is hood-shaped or cuculliform, if not, it is mitre-shaped or mitriform. The particular structure of all our genera of Mosses, and of the following order, is illustrated in the plates of the Manual of the Botany of the Northern United States ; to which the student is referred for details. 973. Ord. Hepatic® (Liverworts). Frondose or Moss-like plants, of a loose cellular texture, usually procumbent and emitting rootlets from beneath; the calyptra not separating from the base, but usually rupturing at the apex ; the sporangium or capsule not opening by a FIG. 1300. Mnium cuspidatum. 1301. The calyptra detached from the spore-case. 1302. Magnified spore-case, from which the lid or operculum, 1303, has been removed, showing the peristome. 1304. A portion of the annulus or ring under the lid, more magnified. 1305. A portion of the Outer and inner peristome, highly magnified. 1306. The so-called flowers in a young state, consisting of the pistillidia 5) and the antheridia , with some cellular jointed threads intermixed ; the involucral leaves cut away. 1307. One of the antheridia more magni- fied (with some accompanying cellular threads), opening at the apex, and discharging the con- tents. 1308. Simple peristome of Splachnum ; the teeth united in pairs. 1309. Double peris- tome of Hypnum ; the exterior spreading. 1310. Physcomitrium (Gymnostomum) pyriforme. 1311. Its calyptra, detached from, 1312, the theca. 1313. The lid removed from the orifice, which is destitute of a peristome.504 ILLUSTRATIONS OF THE NATURAL ORDERS. lid, containing spores usually mixed with elaters (which are thin, thread-like cells, containing one or two spiral fibres, uncoiling elas- tically at maturity). Vegetation sometimes frondose, i. e. the stem and leaves confluent into an expanded leaf-like mass ; sometimes foliaceous, when the leaves are distinct from the stem, as in true Mosses: the leaves are entire or cleft, two-ranked, and often with an imperfect or rudimentary row (amphigastria) on the under side of the stem. The matured pistillidium forms the sporangium or capsule, which is either sessile or borne on a long cellular pedicel, and de- hiscent by irregular openings, by teeth at its apex, or lengthwise by two or four valves. The perianth is a tubular organ enclosing the calyptra, which directly includes the pistillidium. Surrounding the perianth are involucral leaves of particular forms. The an- theridia in the foliaceous species are situated in the axils of peri- gonial leaves. 974. Sllbord. Ricciacca: consists of a few chiefly floating plants, root- ing from beneath, with their fructification immersed in the frond, the sporangium bursting irregularly. No involucre nor elaters. — Ex. Riccia. 1314 1315 1315 1317 1318 975. Subord. AntllOCerotCfE. Terrestrial frondose annuals, with the fruit protruded from the upper surface of the frond. Perianth none. Sporangium pod-like, one- or two-valved, with a free central colu- mella. Elaters none or imperfect. 976. Sllbord. IUarchanliacea! {True Liverworts). Frondose and ter- restrial perennials, growing in wet places, with the fertile receptacle raised on a peduncle, capitate or radiate, bearing pendent calyptrate FIG. 1314,1315. Riccia natans, about the natural size. 1316. Magnified section through the thickness of the frond, showing the immersed sporangia ; one of which has burst through and left an effete cavity. 1317. Magnified vertical section of one of the sporangia, with the contained spores. 1318. Sporangium torn away from the base, and a quaternary group of spores, united and separated.CRYPTOGAMOUS OR FLOWERLESS PLANTS. 505 sporangia from the under side: these open variously, but are not four-valved. Elaters with two spiral fibres. 977. Suliord. Jungermanniacca;. Frondose or mostly foliaceous plants ; with the sporangium dehiscent into four valves, and' the spores mixed with elaters. Vegetables composed of parenchyma alone, forming a mass or stratum (thaUus, 109, 727), or consisting of a congeries of cells, or even of separate cells, never exhibiting a marked distinction into root, stem, and foliage, or into axis and leaves. 978. Ol’d. Hellenes {Lichens) form the highest grade of this lower series. They consist of flat expansions, which are rather crustaceous than foliaceous ; while some are nearly pulverulent. In several the vegetation rises into a kind of axis, or imitates stems and branches; as in the Cladonia coccinea, which abounds on old logs (Fig. 1327) ; or in Cladonia rangiferina, the Reindeer Moss ; also in Usnea, where it forms long, gray tufts, hanging from the boughs of old trees in our Northern forests. Lichens are never aquatic, but grow on the ground, on the bark of trees, or on exposed rocks, to which the proper rock- Lichens adhere by their lower surface, with great tenacity, while by FIG. 1319. Steetzia Lyellii, with the young fructification still included in the tubular peri- anth. 1320. Dehiscent sporangium of a Jungermannia, on its fruit-stalk, with some of the leaves at its base, magnified enough to exhibit its cellular structure. 1321. Two elaters from the same (a, in an entire state ; 6, with only the threads remaining), and some spores, highly magnified. b a Class V. Thallophytes. 43506 ILLUSTRATIONS OF THE NATURAL ORDERS. the upper they draw their nourishment directly from the air. The fructification is in cups, or shields (apothecia), 'resting on the surface of the thallus, or more or less immersed in its substance, or else in pulverulent spots scattered over the surface. A magnified section through an apothecium (Fig. 1324) brings to view a stratum of elongated sacs (asci), with filaments intermixed, as seen detached and highly magnified at Fig. 1325. Each ascus, or sac, contains a few spores: these divide into two, which, however, generally remain 1321 1325 1327 1322 coherent. For a description of the Lichens of this country, the student is referred to Professor Tuckerman’s Synopsis of the Li- chenes of New England, the other Northern States, 8rc. and to his Lichenes Arner. Sept. Exsiccati, illustrating them by named speci- mens. FIG. 1322. A stone upon which several Lichens are growing, such as (passing from left to right) Parmelia conspersa, Sticta miniata, Lecidea geographica (so called from its patches re- sembling the outline of islands, &c. on maps), &c., &c. 1323. Piece of the thallus of Parme- lia conspersa, with a section through an apothecium. 1324. Section of a smaller apothecium, more magnified. 1325. Two asci and their contained spores, with the accompanying filaments, highly magnified. 1326. Section of a piece of the thallus of Sticta miniata, showing the im- mersed apothecia. 1327. Cladonia coccinea, bearing its fructification in rounded red masses on the edges of a raised cup.CRYPTOGAMOUS OR FLOWKRLESS PLANTS. 507 979. Ord. Fungi (Mushrooms, Moulds, fyc.) are parasitic (150, 153) flowerless plants, either in a strict sense, as living upon and draw- ing their nourishment from living, though more commonly languish- ing, plants and animals, or else as appropriating the organized mat- ter of dead and decaying animal and vegetable bodies. Hence they fulfil an office in the economy of creation analogous to that of the infusory animalcules. Those Fungi which produce Rust, Smut, Mildew, &c. are of the first kind ; those which produce Dry-rot, &c. hold a somewhat intermediate place ; and Mushrooms, Puff-balls, &c. are examples of the second. Fungi are consequently not only destitute of anything like foliage, but also of the green matter, or chlorophyll, which appears to play an essential part in vegetable assimilation. A full account of the diversified modifications of struc- ture that Fungi display, and of the remarkable points in their economy, would require a large volume.. We will notice three sorts only, which may represent the highest, and nearly the lowest, forms of this vast order or class of plants. They all begin (in germina- tion or by offsets) with the production of copious filamentous threads, or series of attenuated cells, appearing like the roots of the fungus that arises from them (Fig. 1328, 1330), and to a certain extent performing the functions of roots : this is called the mycelium, and is the true vegetation of Fungi. The subsequent developments properly belong to the fructification, or are analogous to tubers, rhizomas, &c. In one part of the order, the masses that arise, of various definite shapes, and often attaining a large size, contain in their interior a multitude of asci (Fig.1329), enclosing simple or double sporules, just as in Lichens. The esculent Morel has this kind of fructification ; as well as the less conspicuous Splueria (Fig. 1328), which is in other respects of a lower grade. The Agarics, like the Edible Mushroom (Fig. 1330), produce their spores in a different way. Rounded tubercles appear on the mycelium ; some of these rapidly enlarge, burst an outer covering which is left at the base (the volva, or wrapper), and protrude a thick stalk (stipes), bearing at its summit a rounded body that soon expands into the pileus, or cap. The lamella, or gills (hymenium), that occupy its lower surface, consist of parallel plates (Fig. 1331), which bear naked sporules over their whole surface. A careful inspection with the microscope shows that these sporules are grouped in fours ; and a view of a section of one of the gills shows their true origin (Fig. 1332). Certain of the cells (basidia), one of which is shown more508 ILLUSTRATIONS OF THE NATURAL ORDERS. magnified at Fig. 1333, produce four small cells at their free sum- mit, apparently by gemmation and constriction : these are the spores. It is maintained that the larger intermingled cells, (of which one is shown at Fig. 1332, a,) filled with an attenuated form of matter, are the analogues of antheridia. The lowest Fungi produce from their mycelium only simple or branching series of cells (Fig. 92-94). The mycelium itself either ramifies through decaying organized matter, as the Moulds, &c.; or else — like the Blight and Rust in grain, and the Muscardine so destructive to silkworms, and others 1331 1333 1332 so destructive to the Grape, the Potato, &c. — it attacks and spreads throughout living tissues, often producing great havoc before its fructification is revealed at the surface. Sometimes the last cells of the stalks swell into a .vesicle, in which the minute sporules are formed ; as in Fig. 92. Sometimes the branching stalks bear single sporules, like a buncli of grapes (Fig. 94), or long series of cells, or FIG. 1328. Sphaeria rosella. 1329. Asci from its interior, containing- sporules, highly mag- nified. 1330. Agaricus campestris, the Edible mushroom, in its various stages. 1331. Section through the pileus, to display the gills. 1332. A small piece Of a slice through the thick- ness of ono of the gills, magnified ; showing the spores borne on the summit of salient cells of both surfaces. 1333. One of the sporule-bearing cells, with some subjacent tissue, more magnified.CBYPTOGAMOUS OB FLOWEBLESS PLANTS. 509 sporules, in rows, like the beads of a necklace (Fig. 93), which, separating, become the rudiments of new plants. 980. Ord. Alga! (Seaweeds). This vast order consists of aquatic plants, for the most part strictly so, but some grow in humid ter- restrial situations. The highest forms are the proper Seaweeds ( Wrack, Tang, Dulse, Tangle, &c.) ; “ some of which have stems ex- ceeding in length (although not in diameter) the trunks of the tallest forest-trees, while others have leaves (fronds) which rival in expan- sion those of the Palm.” “ Others again are so minute as to be wholly invisible, except in masses, to the naked eye, and require the highest powers of our microscopes to ascertain their form and struc- ture.” Some have the distinction of stems and fronds; others show simple or branching solid stems only ; and others flat foliaceous ex- pansions alone (Fig. 95), either green, olive, or rose-red in hue. From these we descend by successive gradations to simple or branching series of cells placed end to end, such as the green Con- fervas of our pools, and many marine forms: we meet with congeries of such cells capable of spontaneous disarticulation, each joint of which becomes a new plant, so that the organs of vegetation and of fructification become at length perfectly identical, both reduced to mere cells ; and finally, as the last and lowest term of possible vege- tation, we have the plant reduced to a single cell, giving rise to new ones in its interior, each of which becomes an independent plant (Fig, 79 -83, 18-22). Our Alga3 should be studied by the aid of the admirable Nereis Boreali-Americana, or History of the Marine Algce of North America, by Professor Harvey, published by the Smithsonian Institution. For the fresh-water species we have no American work. The main divisions of Algo; are into the following suboi-ders. 981. Subord. Mrianospermca!, or Fucacca;, the Olive-green Seaweeds; having dark-colored spores and generally an olive-green color, such as the common Roekweed, Gulfweed, &c. The fertilization of these spores has already been described (GG1). 982. Subord. Rhodospcrmese, or Floridcac, the Rose-red Seaweeds, so called from their prevailing color. These, the most beautiful of Algaj (including the Dulse, Laver, &e.) have two kinds of spores; one large, simple, and superficial; the others dispersed through the interior of the frond, and formed four together in a mother cell. 983. Sllbord. ClllorospcrmctE, the Bright-green Algce, the spores and the vegetation of which are generally of a lively green hue, are more 43*510 ILLUSTRATIONS OP THE NATURAL ORDERS. simple m structure, and include the fresh-water kinds generally, as well as numerous marine species ; among them those of single rows of cells, or of single cells (100 — 105, 656-660). Some of these fruc- tify by conjugation (655-657), as is the case in those simplified forms which compose the 984. Subonl. Dcsillidiacetc, which are microscopic and infusory green Algce of single cells (Fig. 100, 655), often of crystal-like forms, in- vested with mucus, and belonging to fresh water. They multiply largely by division, but strictly propagate only by conjugation. Many of them have long been claimed for the animal kingdom, or es- teemed of ambiguous nature, on account of the free movements they exhibit; but this affords no real distinc- tion. (Chap. XII., XIII.) More ambiguous still, and on the lowest confines of the vegeta- ble kingdom, are those minute vegetables, as they doubtless are, which constitute the 985. Sultord. DiatomacctB. These differ from the last chiefly in the brown instead of green color of their contents, in the siliceous and durable nature of their cell-wall, and in being natives of salt instead of fresh water. Their movements, as they break up from their connections, are still more vivid and varied. Some are fixed; others are free. Some are extremely minute: others form clusters of cells of considerable size. All require a compound microscope for their study, and a full treatise is needed to do them justice. 986. Ord. Characetl. The Chara Family consists of' a few aquatic plants, which have all the simplicity of the lower Algte in their vegetation, being composed of simple tubular cells placed end to end, and often with a set of smaller tubes applied to the surface of the main one (Fig. 1335, 1336). Hence they have been placed among Alga?,. But their fructification is of a higher order. It con- sists of two kinds of bodies (both shown in Fig. 1335), of which FIG. 1334. Branch of the common Chara, nearly the natural size. 1335 A portion magni- fied, showing the lateral tubes enclosing a large central one (a portion more magnified at 1336); also a spore, invested by a set of tubes twisted spirally around it; and the antheridium borne at its base.THE ARTIFICIAL SYSTEM OF LINNAEUS. 511 the smaller (and lower) contains antheridia of curious structure, provided with slender and active spermatozoids, while the upper and larger is a sporocarp, formed of a budding cluster of leaves wrapped around a nucleus, which is a spore or sporangium. The order might perhaps have been introduced between the Equise- taceaj (to which the verticillate branches show some analogy) and the Hydropterides ; but its true position is hard to determine. CHAPTER IV. OF THE ARTIFICIAL SYSTEM OF LINNAEUS. 987. The difference in principle between an artificial and a natu- ral system of classification has already been indicated (715). No one better understood this than Linnaeus, when, finding it impossible in his day to make a natural classification available for ordinary use, he proposed, as a temporary substitute, the elegant artificial scheme which bears his name. As this system is identified with the history of the science, which in its time it so greatly promoted, and as most systematic works have until recently been arranged upon its plan, it is still necessary for the student to understand it. Its principles are so simple, that a brief space will amply suffice for its explanation. 988. It must be kept in mind, that an artificial scheme does not attempt to fulfil all the conditions of natural-history classification. Its principal object is to furnish an easy mode of ascertaining the names of plants ; their relationships being only so far expressed as the plan of the scheme admits. All higher considerations are of course sacrificed to facility. In the Linnsean classification, the species of a genus are always kept together, whether or not they all accord with the class or order under which they are placed. Its lower divisions, therefore, namely, the genera and species, are the same as in a natural system. But the genera are arranged in arti- ficial classes and orders, founded on some single technical character, and have no necessary agreement in any other respect; just as words are alphabetically arranged in a dictionary, for the sake of convenience, although those which stand next each other have, it may be, nothing in common beyond the initial letter.512 THE ARTIFICIAL SYSTEM OF LIXNJECS. 989. The classes and orders Linnaeus founded entirely upon the number, situation, and connection of the stamens and pistils ; the office and importance of which he had just set in a clear light. 990. The classes, twenty-four in number, were founded upon modifications of the stamens, and have names of Greek derivation expressive of their character. The first eleven comprise all plants with perfect flowers, and with a definite number of equal and un- connected stamens. They are distinguished by the absolute number of these organs, and are designated by names compounded of Greek numerals and the word andria (from avrjp), which is used meta- phorically for stamen, as follows : — Class 1. Monandria includes all such plants with one stamen to the flower; as in Hippuris. 2. Diandria, those with two stamens, as in the Lilac. 3. Tkiandria, with three stamens, as in the Valerian, &c. 4. Tetrandria, with four stamens, as in the Scabious. 5. Pentandria, with five stamens, the most frequent case. 6. Hexandria, with six stamens, as in the Lily Family, &c. 7. IIeptandria, with seven stamens, as in Horsechestnut. 8. Octandria, with eight stamens, as in Evening Primrose, &c. 9. Enneandria, with nine stamens, as in the Rhubarb. 10. Decandiua, with ten stamens, as in Rhododendron. 11. Dodecandria, with twelve stamens, as in Asarum and the Mignonette ; extended also to include those with from thirteen to nineteen stamens. 991. The two succeeding classes include plants with perfect flow- ers, having twenty or more unconnected stamens, which, in 12. Icosandria, are inserted on the calyx (perigynous, 4C7), as in the Rose Family; and in 13. Polyaxdria, on the receptacle (liypogynous, 46G), as in the Buttercup, Anemone, &c. 992. Their essential characters are not indicated by their names; the former merely denoting that the stamens are twenty in number; the latter, that they are numerous. — The two following depend upon the relative length of the stamens, namely, 14. Didyxamia, including those with two long and two short stamens (Fig. 407) ; and 15. Tetradynamia, those with four long and two short sta- mens, as in Cruciferous flowers (Fig. 40G).THE ARTIFICIAL SYSTEM OF I.INNA5U9. 513 993. Their names are Greek derivatives, signifying in the former that two stamens, and in the latter that four stamens, are most pow- erful. — The four succeeding are founded on the connection of the stamens: — 16. Monadei.piiia (meaning a single fraternity), with the filaments united in a single set, tube, or column, as in all the Mallow Family, &c. 17. Diadf.lphia (two fraternities), with the filaments united in two sets or parcels. 18. Folya Delphi A (many fraternities), with the filaments united in more than two sets or parcels. 19. Syngenesia (from Greek words signifying to grow to- gether), with the anthers united in a ring or tube, as in all Composite (844). 994. The next class, as its name denotes, is founded on the union of the stamens to the style: — 20. Gynandria, with the stamens and styles consolidated, as in the Orchis Family (Fig. 468). 995. In the three following classes, the stamens and pistils are found in separate blossoms: — 21. Moncecta (one household) includes all plants where the stamens and pistils are in separate flowers on the same individual; as in the Oak, &c. 22. Dicecia (two households), where they occupy separate flowers on different individuals ; as in the Willow, Pop- lar, Moonseed (Fig. 413, 414), &c. 23. Polygamia, where the stamens and pistils are separate' in some flowers and united in others, either on the same, or two or three different plants; as in most Maples. 996. The only remaining class, 24. Cryptogamia, is inferred to have concealed stamens and pistils (as the name imports), or the analogues of these organs, and includes the Ferns, Mosses, Lichens, &c., which are now commonly termed Cryptogamous or Flow- erless Plants (651). 997. The characters of the classes may be presented at a single view, as in the subjoined analysis : —Plants having Synoptical View of the Linn.ean Classes. of equal length: both found in the same flower, the stamens separate • from the pistils, unconnected with each other, and of unequal length: connected with each other stamens and pistils mani- fest, the stamens adherent to the pistil Stamens 1 .......... “ 2 . .... “3 “4 ... “ 5 . . “ 6 . . . “7 . “8 . “9 . . . . . “ 10 . “11-19............. “ 20 or more, adherent to the calyx “ 21 or more, not adherent to the calyx 1. Monaxdria. 2. Diandria. 3. Triandria. 4. Tetrandria. 5. Pentandria. 6. Hexandria. 7. Heptandria. 8. Octandria. 9. Enneandrla. 10. Decandria. 11. Dodecandria. 12. ICOSANDRIA. 13. POLYANDRIA. I two long and two short stamens | four long and two short stamens 14. Didynamia. 15. TETRADrNAMLA. \ by their filaments in j by their filaments in 1 by their filaments in [ by their anthers a single set two sets more than two sets . . 16. Moxadelphia. 17. Diadelphia. . 18. POLYADELPHLA. 19. Syxgenesla. 20. Gynandria. in separate flowers the stamens and pistils concealed, or none f in the same individuals ... 21. Mon, 210. Indehxscent (fruits) : not opening, at least not in a regular way, 310, 313. Indeterminate inflorescence, 210. India-rubber, 57. Indigenous: of spontaneous and original growth in a country. Indigo, 414, 415. Individual, 20, 131, 352. Individuality, 132, 352. Indumentum: any hairiness or downy covering. Induplicate: bent or folded inwards, 145, 273. Indusium: the proper covering of the fruit-dots of Ferns; any peculiar membranous covering, 501. Inequilateral: unequal-sided. Inferior: underneath, 252; or same as anterior: thus the inferior petal, &c. is the same as the anterior one, 237. Inflated: bladdery. Inflexed: abruptly bent inwards. Inflorescence, 209. Infra-ax illary: originating below the axil. Infundibular, infundibuliform: funnel- shaped ; i. e. a tube enlarging up- wards ; 277, fig. 1049. Innate: borne directly on the apex of a thing, 282. Innovations: new shoots or new growths. Inorganic: unorganized. Inorganic constituents, 179. Inosculating: opening into each other; anastomosing, 49. Inserted: attached to, 224, 250. Insertion: the place or the mode of junc- tion of leaves with the stem, &c., 133. Inter-, in composition : between ; as Intercellular: between the cells. Intercellular spaces or passages, 24, 50. Intercellular system, 50. Interlaced tissue, 48. Internal glands, 51. Internodes, 92. Interpe'tiolar: between the petioles, 171. Inteiruptedly pinnate, 164, fig. 285. Intine: the inner coat of a pollen-grain. Intrafoliaceous: within or before a leaf, 171, as the stipules in fig 305. Introflexed: bent strongly inwards. Introrse: turned inwards towards the axis, 282. Intruse: appearing as if pushed inwards or indented. Inverse: inverted; suspended. Involucellate: furnished with an Involuce'llum, or fnvoluccl: a secondary or partial involucre, 216.' Involucrate: provided with an hvolucrum, or involucre: an outer or accessory covering; a set of bracts surrounding a flower-cluster; 214, fig. 321, &c. Involute: rolled inwards, 144, 273. Ipecacuanha, 393, 433. Iridaceae, 490. Irregular : unequal in size or in shape, 253, 277. Irregularity, 253. Irritability, 345. Isdchroiis: one-colored. Isoetineaj, 502. Isdmerous, or isdmeric: the parts equal in number. Isost&nonous: the stamens as many as the petals or sepals. Jalap, 455. Jasminaceae, 459. Jolly, 55, 310. Jointed: separate or separable trans- verse^ into pieces (joints), 92. Juba: a loose panicle, as of Grasses. Juga: the ridges of the fruit of Umbel- liferae, 426.538 GLOSSARY AND INDEX. Jugae: the pairs of partial petioles or leaflets of a, pinnately-compound leaf, 164. Juglandaceac, 476. Jujube, 408. Julus: a name for a catkin. Julaceous: shaped like or resembling a catkin. Juncacc®, 495. Junengine*, 487. Jungermanniace®, 505. Juniper-berries, 480. Jute, 400. Keel: see Carina, 254. Keeled: furnished with a keel or sharp ridge underneath. Kernel of an ovule, 297, or seed, 322. Keg-fruit, 314. Kidney-shaped: see Reniform ; 157, fig. 245. Kingdom, 362, 15. Kinic acid, 433. Kino, 414. Knot: sec Node, 92. Knotted: a cylindrical body swollen into knobs at intervals. Kramcriacctc, 412. Labdllum: the lip, or lower petal of an Orchidcous flower. Labiat®, 450. Labiate: two-lipped, 278. Labiatiflorae, 436. Lae, 475. Laciniate: slashed ; cut into narrow in- cisions ; these are called lacinice. Lactescent: yielding milky juice. Ldcunose: full of depressions or exca- vations (lacunae). Lacustrine: belonging to lakes. Ladanum, 394. Lcevigate: smooth as if polished. Lagdniform: shaped like a Florence flask (lagena). Lalo, 399. Lamellae: thin plates, like the gills of an Agaric, 507, &c. Lamellar, or lamellate: composed of flat plates. Ldmina (a plate): the blade of a leaf, petal, &c., 145,276. Lanate, lanose: woolly; i e. clothed with soft interlaced hairs. Lanceolate: lance-shaped ; fig 239. Laniigiuous: cottony or woolly. Latent buds, 167. Lateral,: belonging, or attached to, the sides of an organ. Latex: milky or proper juice, 49. Laticiferous tissue or resse/s, 49. Lauracc®, or Laurinc®, 466. Lax: loose; the opposite of close or crowded. Layerinq, 102. Leaf; 133. Leaf-arrangement (phyllo taxis), 133. Leaf-bud, 72, 93. Leaf-green, 58. Leaflet: a separate piece or partial blade of a compound leaf, 163. Leaf-stalk, 145, 170. Leaf-scars, 94. Leathery: see Foliaceous. Legume: a fruit like a Pea-pod, 315. Legumine*198. Leguminos® (Leguminous Plants), 412. Leguminous: relating to legumes. Lemnace®, 486. Lemon, 401. Lentibulaceae, 445. Lenticels: little spots on the bark, whence roots often issue. Lenticular: lens-shaped; double-convex. Lentiginose: freckled, or dusty-dotted. Lepals: sterile transformed stamens. Lepidote: leprous ; scaly or scurfy, 52. Leucanthous: white-flowered. Liber: the inner fibrous bark, 120, 127. Lid: see Operculum, 502. Liehenes (Lichens), 505. Lichenology: the part of Botany devoted to Lichens. Licorice, 414. Ligneous: woody in texture. Lignine, 36,195. Lignum-vitce, 405. Ligulate: strap-shaped, 255; having a Ligule: a strap-shaped corolla, 255, fig. 325, d; the appendage between the blade and the sheath of the leaf in Grasses, 170. Liguliflorse, 436. Liguliflorous: when a head consists of ligulate flowers only, as Cichory, fig. 323. Liliace®, 493. Liliaceous: lily-like, 276. Limb (limbus, a border) ; the expanded part or border of a corolla, calyx, &c., or the lamina or blade of a petal, &c., 145, 276. Limbate: bordered. Lime, 401. Limnanthaceae, 404. Linacete, 402. Tjine: the twelfth of an inch. (In deci- mal measures, the tenth of an inch.) Linear: narrow and much longer than broad, the two margins parallel; fig. 240. TJneate: marked with lines. Lineolate.: marked with fine or obscure lines.GLOSSARY AND INDEX. 539 Linguiform, or Ungulate: tongue-shaped, as the leaves of Hound's-tongue. Lip: the two lobes a bilabiate calyx or corolla; the lower petal of au Orchidcous plant. Littoral, or litoral: growing on shores. Livid: pale lead-color. Loasacece, 421. Lobe: any division or projecting part of an organ, especially a. rounded one, 275. Lobed, lobate: divided into lobes ; fig. 2G0, 2G4. Lobeliace®, 438. Ldbulate: bearing small lobes (IdbuU). Ldcellate: having secondary cells (or locelli). Locdllus (plural, locelli) : a secondary cell, or a division of a cell. Ldculament, 316 ; same as loculus. Ldcufar: having cells. Loculicidid, or loculicide: dehiscence opening directly into the back of a cell; 316, fig. 583, 585. Ldculose: partitioned off into cells, as the pith of Poke, &c. Loculus (plural, loculi): the cells of an ovary, anther, &c. Locusla : a spikelct or flower-cluster of Grasses. Lodicules (lodtculce): the minute scales inside of the paleaeof Grasses, 497. Loganiaecte, 433. Logwood, 414. Lament: a jointed legume; 315, fig. 581. Lomentaceous: bearing or resembling a loment. Longitudinal tissue or system, 45, 50, 112. Lonicereai, 431. Loranthaeete, 469. Lorate: thong-shaped. Lucid: shining. Lunate: crescent or half-moon shaped. Lunulate: diminutive of the last. Lupuline : waxy grains "bn the scales of Hops. Lurid: dingy brown. Lutescent: yellowish. (Lutens: yellow). Lycopodiacese, 501- Lycotropous, or lycdtropal: an orthotro- pous ovule curved into a horse- shoe form. Lyrate, lyre-shaped, 161, fig. 138, 278. Lyrately pinnate, 164, fig. 285. Lythraceoe, or Lytliariese, 418. Mace: the arillus of Nutmeg, 322, 383. Maculate: spotted or blotched. Madder, 432. Magnoliacc®, 381. Mahogany, 401. Maize, 498. Male flower, 261. Malpighiacese, 409. Malpighiaceous hairs: hairs fixed by their middle, as in the foregoing order, in Comus, &c. Malvaceae, 397. Mamillale, or mdmillar: bearing little prominences on the surface. Mdmmce/orm: teat-shaped. Mammee-apple, 400. Mammose : bearing larger prominences, like breasts. Mango, 406. Mangosteen, 400. Manicate (gloved): covered with a woolly coat which may be stripped off whole. Manilla hemp, 490. Manna, 460. Many-cleft: cut as far as the middle into several divisions, 159. Many-headecl: see Multicipital. Marantacese : see Cannaceoe Marcesccnt: gradually withering with- out falling off, 279. Marcliantiacece, 504. Marginal: belonging to the margin. Marginate: furnished with a margin of different texture or color from the rest. Maritime: belonging to the sea-shore. Markings on cells, 3, 6. Marmorate: marbled. Marsiliacete, 502. Mas: male, masculine; belonging to the stamens. Masked: see Personate, 278. Mealy: see Farinaceous. Medial: belonging to the middle. Medulla: pith, 118. Me'dullary rays, 117, 119. Medullary sheath, 119. j\fedullose, or medullary: pith-like. Meiostdrnonous: having fewer stamens than petals. Melanospermete, 509. Melanthacece, 494. Melastomacete, 418. Meliaceaj, 401. Melon, 423. Membranaceous, or membranous: thin and soft, like a membrane. Meniscoid: shaped like a meniscus or concavo-convex lens. Menispermace^e, 383. Menyanthideoe, 457. J\ferenchyma, 41. Me'ricarp: half a cremocarp, 426. Merismdtic: dividing into parts, 28. Merithall: a name for an internode. Merous, in Greek compounds : the parts540 GLOSSARY AND INDEX. of a flower : see Dimerous, Trime- rous, &c. Mesembryanthemaeeae, 397. Mesocarp: tlie middle layer of a peri- carp, 310. Mesophldum: the middle bark or green layer, 121. Mesophyllum: the parenchyma of a leaf between the skin of the two sur- faces. Metamorphosed: that which has under- gone. Metamorphosis: the transformation of one organ into another homologous one, 228, 231. Micropyle: the orifice of a seed, 298. Midrib : the central or main rib, 155 Milky juice, 49. Mimosete, 413. Mineral constituents of plants, 179. Miniate: vcrmilion-color. Mitriform: mitre-shaped, 503. Mollugincai, 395. Monadelphia, 513. Monadelphous: with filaments united into a tube, or ring; 280, fig. 462. Monandria, 512. Mondndious: with a single stamen, 279. ]\fondnihot(s: onc-flowercd. Monihform: necklace-shaped; cylin- drical and contracted at intervals. Monimiaccce, 382. Monkey-bread, 399. Mono-, in Greek compounds: one or single. Monocdrpellary: of one carpel. Monocdrpic, or monocarpian : once-fruit- ing, 101. Monocc'phalons: bearing a single head. Monochlarnydeous: with a single floral envelope ; i. c. apetalous, 260. j\fonoclinons: hermaphrodite. Monocotyledonous: one-cotvledoncd, 79, 326. Monocotyledons or Monocotylcdonous Plants, 113, 326, 370, 482. Monoeeia, 513. Monoecious: stamens and pistils in sep- arate flowers on the same individ- ual, 262. Monogamia, 516. Monogynia, 515. Rfondgynous: with one pistil or style, 287. Monoicous: same as monoecious. Mondmei'ous: the parts of the flower single, 234. Monopetalous: one-petalled, but it is used for gamopetalous, viz. petals more or less united into one body, 249, 275. Monophyllous: one-leaved, of one piece, 275. Mondpterous: one-winged. Monopyrenous: one-stoned. Monosepalous: the calyx of one piece, 249. Monospe'nnous: one-seeded. Monostichous: in one vertical rank, 134. J\fondstylous : with one style. Monotropcie, or Monotropaceaj, 440. Monster, monstrous (430): developed in an unnatural manner. Morphine, 57. Morphology, 14, 60, 224- ]\fdrphosis: the manner of development. Afoschate * exhaling the odor of musk. Moulds, 65. Mucilage: dissolved vegetable jelly, or dextrine, 55, 193. ilfucilaginous, mucose, or mucous: slimy. Macro: a short, sharp point. Mucronate: abruptly tipped with a mu- cro; 162, fig. 276, 231. Mucrdnulaie: tipped with a minute mu- cro. Mulberry, 475. Mule: a hybrid. Multangular: many-angled. Multi-, in Latin derivatives: many; as, Multicipital (multiceps) : many-headed; where several buds or shoots pro- ceed from the crown of one root. Multifarious: many-sided. Multi fid: many-cleft, 159. Multijldrous: many-flowered. Multi jugate: in many pairs. Mu/tildcular: many-celled. Multiple: compound. Multiple fruits, 309, 318. Multisdrial: in several horizontal ranks. Multiseptate: many-partitioned. Muricate • rough with short and hard points. l\furiculate: minutely muricate. Musacete, 490. Muscardine, 508. Muscarifonn: ^rush-shaped. Musci (Mosses), 502. Musciform: moss-like. Muscology: the department of Botany which treats of Mosses. Mustard, 389. Muticous : pointless ; blunt. Mycelium, 507. Mycology, or Mycetdlogy: the depart- ment of Botany which treats of Fungi. Mijcropyle: see Micropyle. Myricaecae, 477. Myrsinaccro, 443. Myristicaoeae, 383. Myrrh, 407. Myrtaceae, 418.GLOSSARY AND INDEX. 541 Naiadacc®, 487. Naked flowers: same as achlamydeous; or destitute of involucre, &c. Naked ovules and seeds, 296, 320. Names of species and genera, 363 • of orders, tribes, &c., 373. Ndpijbrm: turnip-shaped, 84. Natant: floating under water. Natural system, 365, 366. Naturalized: species introduced, but growing completely spontaneous, and propagating by seed. Navicular: boat-shaped. Nebxdose: clouded. Neck: the junction of root and stem. Necklace-shaped: see Moniliform. Nectar: the honey of a flower, or any sweetish exudation. Nectary (nectarium) : a place or thing in which nectar is secreted : for- merly applied also to any anoma- lous part or appendage of a flower, whether known to secrete honey or not, as to the spur-shaped petals of Aquilegia, fig. 647, or the two singular-shaped petals of Aconi- tum, 257, fig. 402, 404. Needle-shaped: see Acerose. Nelumbiace* (Nelumbo), 385. Ndmeous: filamentose; composed of threads. Nervation: the arrangement of the Nerves: parallel and simple veins. Nerved: nervate; furnished with nerves, 154. Nervose: abounding in nerves. Netted: same as reticulated. Netted-veined, 154. Neurose: same as nervose. Neutral: without sexes. Neutral flowers: having neither stamen . nor pistil, 263, 436. Neutral quaternary products, 196. New Zealand Hemp, 492. Nidulant: nestling in. Nitid (nitidus): smooth and shining. Niveous: snow-white. Nodding: curved so that the apex hangs down. Node (knot) : the place on a stem where a leaf is attached, 92. Nodose: knotty; swollen in some parts, contracted at others. Nddulose: diminutive of the last. Normal: according to rule. Notate: marked by spots or lines. Notorhizal: the radicle bent round to the back of one cotyledon; same as incumbent. Nucumentaceous: nut-like. Nucelle: same as nucleus. Nuciform: nut-like. Nucleus: the kernel, 297, 320, 322. Nucleus of a'cell, 26. Nuculanium : a name for a berry like a grape. Nucule: a diminutive nut, stone, or kernel. Nuculose: containing nucules or nut- lets. Numerous: same as indefinite. Nut, 314. Nutlet: a small nut, or the small stone of a berry-like drupe. Nutmeg, 383. Nutant: nodding. Nutrition, 61, 177. Nux-vomica, 434. Nyctaginaceae, 463. Nymphaeaceje, 385. Oat, 498. Ob- (over against) signifies inversely; as, Obcomprcssed: flattened fore and aft, in- stead of laterally. Obcordate: heart-shaped inverted; 162, fig. 274, 233. Obldnceolate: lance-shaped, but broader upwards. Oblique, referring to shape, unequal- sided, 165. Obliteration, 309. Oblong: elliptical, or approaching it, and much longer than wide; fig. 242. Obdvate: inversely ovate; 157, fig. 232. Obtuse: blunt; the apex an obtuse an- gle; 162, fig. 270, 236. Obverse: same as ob. Obvolute: a modification of convolute, 145. Ocdllate: eyed; a circular patch of , color within another patch. Ochrea (a boot): a tubular stipule; 171, fig. 305. Ochreate: furnished with ochrcae. Ochroleucous: ochre-colored (pale dull yellow) verging to white. Octo-: eight; in composition in such words as the following. Octagynia, 515. Octagynous: with eight pistils or styles. Octdmerous: the parts in eights. Octandria, 512. Octandrous: with eight stamens. Octopetadous: of eight petals, 276. O'culate: eyed; same as ocellate. Officinal (belonging to the shop): ap- plied to plants, &c. used in medi- cine or the arts. Offset, 102. Oilnut, 469. Oils, 56, 57. 46542 GLOSSARY AND INDEX. Okra, 398. Oleaceae, 459. Oleraceous: of the nature of, or fit for, pot-herbs. Oligo-, in Greek derivatives : few ; as Oligandrous: having few stamens. Oligosp&mous: few-seeded. Olive, Olive-oil, 460. Onagracese, 419. One-cclled plants, 61. One-sided: see Secund and Unilateral. Oophondia: the larger and compound spores of Lycopodiacete. Opaque: the reverse of shining ; dull. Opdrculate: furnished with a lid or Operculum: a lid, such as that of the spore-case of Mosses, 502. Ophioglosseae, 501. Opium, 389. Opposite (leaves, &e.): opposed to alter- nate, that is, placed over against each other, 78, 97, 133, 141. A stamen, &c. is said to be opposite a petal, when it stands before it (248), as in fig. 435 and 670. Oppositifolious: opposite a leaf, as the tendrils of Vitis, fig. 767, and the peduncles of Phytolacca, fig. 1086. Orange, 401. Orbicular: circular in outline. Orchidacese, 488. Orders, 359. Ordinal: relating to orders. Organic constituents, 179, 180. Organization, 17. Organography, 14, 60. Organogeny : the development ol1 for- mation of organs, 268. Organs, 18. Organs of Reproduction, 70. Organs of Vegetation, 68, 70, 204. Orobanchacese, 446. Orris-root, 491. Orthopldceous (embryo) : with incum- bent and conduplicate cotyledons, as in Mustard. Orthdtropous, or orthdtropal ovule ; 298, fig. 526. The term when applied to the embryo is used as the con- trary of antitropous, i. e. having the radicle next the hilum, as in an anatropous seed. Osage Orange, 475. Osmundacese, or Osmundinea?, 501. Osseous: of the texture of bone. Ouari Poison, 434. Oval: broadly elliptical; 157, fig. 229. O'vary: the ovule-bearing portion of a , pistil, 223, 287. Ovate: egg-shaped, or like the longitu- dinal section of an egg, fig. 241. Ovoid: a. solid ovate or oval. Ovulate, ovuled, or ovuliferous: bear- . ing ovules. Ovule: an unimpregnated seed or body destined to become a seed, 223, 297. Oxalidacese, 404. Palate: an inward projection of the lower lip of a personate corolla; 278, fig. 459, 460. Pdlea, or paid: a chaff; one of the bracts on the receptacle of Com- posite, 215, 435 ; one of the inner bracts or glumes of Grasses, 497. Paleaceous : chaff-like, or bearing chaff. Paleola: diminutive of palea; one of the minute innermost scales of the flower of Grasses. See Squa- mella. Palme (Palms), 484. Palmate: lobed or divided so that the sinuses all point to the apex of the petiole, either moderately, as in a Maple-leaf, or so as to make the leaf compound, as in Horsechest- nut, when it is the same as Digitate; 161,163,164. Palmate!y lobed, cleft, parted, &c., 161. Palniately 2 - plurifoliolate, 164. Palmate!y veined, 156. Palmatijid: palmatcly cleft; fig. 265. Palmatisect: palmately divided; fig. 267. Paludose, palustrine: inhabiting marshes. Pandanacee, 485. Pdndurate, or panduriform; same as fiddle-shaped. Panicle: a raceme, branched irregular- ly; 216, fig. 326. Panicled, or paniculate: arranged in a panicle. Papaveracere, 388. Papaw, 383, 422. Papayaceaa, 422. Papery: of the consistence of letter- paper. Papilionacese, 413. Papilionaceous: butterfly-like, 253. Papillose, or pdpillate: bearing small, soft projections (papillae, nipples or pimples). Pappose, or pappiferous: hearing a Pappus (thistle-down), 260, 314, 435. Papyraceous: papery. Papyrus, 496. Paracorolla: an appendage or duplicate of a corolla, such as was once called a nectary. Parallel-veined or nerved, 154. Paraphysis: jointed thread-like bodies accompanying the pistillidia of Mosses.GLOSSARY AND INDEX. 543 Parasitic plants, or Parasites: living on the juices of other plants, 88. Parastdmon : same as Staminodium. Parenchyma: soft cellular tissue, 41. Parietal: attached or belonging to the walls, 292. Parietes : wails of an ovary, &c. Paripinnate: same as abruptly pinnate, 163. Parnassiaceae, 394. Parsnip, 426. Parted, or partite: cut almost through; 160, fig. 262, 266. Partial peduncle, 211. Partial petiole, 164. Partial umbel, 216. Parthenogenesis, 300, 340. Passifloraceos (Passion-flowers), 422. Patelliform: kneepan-shaped. Patent: spreading wide open. Patulous: moderately spreading. Pauci-, in Latin derivatives : few ; as Paucifldrous: few-flowered. Peach, 415. Pear, 416. Pear-shaped: ovoid at the extremity, conical at the base. Pectinate : pinnatifid with elose-set and equal lobes, like the teeth of a comb (pecten), 160. Pectine, and Pcctic acid, 55, 310. Pedate: palmate, with the lateral lobes again lobed ; appearing like a bird’s foot, 161, fig. 249. Pedulely: in a pedate mode. Pedicel: the stalk of a particular flower, 211. Pedicellate, pedicdled: having a pedi- cel. Peduncle: a flower-stalk in general, either of one blossom or a whole cluster, 211. Pedunculate, peduncled: having a pe- duncle. Peloria, 278. Peltate: shield-form or target-shaped ; fixed by the centre or some part of the lower surface ; fig. 248, 681. Peltinerved: peltately veined. Pehn form: open cup-shaped. Pendent, pendulous: hanging down. Pemcillate, penicilliform: tipped with a brush of hairs, like a camers-hair pencil. Pennate: same as pinnate. Penniform: fcathcr-like. Penninerved: same as pinnately nerved or veined. Penta-, in Greek derivatives : five ; as Pentacarpellary: of five carpels. Pentacdccous: of five cocci. Pcntagynia, 515. Pentagynous : with five pistils or styles, 287. Pentamerous: of five parts ; 234, 239, fig. 354. Pentandria, 512. Pentandrous : having five stamens, 279. Pentapetalous: of five petals, 276. Pentaphyllous: five-leaved, 275. Pentapterous: five-winged. Pentasepafous: of five sepals, 274. Pentdstichous: in five vertical ranks, 135. Pepo: a Gourd-fruit, 312. Pepper, 456, 469. Pei'ennial: lasting year after year, 84. Perfect flower: one having both stamens and pistils, 261, Perfoliate: when the stem appears to pass through the leaf; 165, fig. 293, 294. Perforate: pierced with holes, or having transparent dots which look like holes. Pergameneous, or pergamentdeeous : like parchment. Peri-, in Greek derivatives : around. Perianth (peridnthium); the floral en- velopes collectively, either of one set (calyx) or of two sets (calyx and corolla), 222. Pericarp: the ovary in fruit, 308. Pericdrpic: belonging to the pericarp. Perichcetial: relating to the Perichceth, or periclmtium: the cluster of peculiar leaves surrounding the base of the fruit-stalk of Mosses. Periclmium: a name for the involucre of Compositaj. Periderm : same as Epiphloeum. Perigone, or perigonium: same as Peri- anth. Perigynium : bristles or other organs, of doubtful nature, around the pistil in Cypcracece, 497. Perigynous: borne on the calyx ; liter- ally around the ovaiy; i. e. when the petals or stamens are adnate to the base of the ovary or to the calyx ; 251, 268, fig. 388, 389, 281. Peripetalous : around the petals. Peripheric: surrounding the circumfer- ence, 325 ; as the embryo around the albumen in fig. 621. Perisperm: the albumen of the seed, 322, or that albumen which is formed in the tissue of the nucleus, 323. Peristome, 502. Peritropous, peritropal (seed): horizon- tal to the axis of the fruit. Perpendicular system of the stem, 112. Persimmon, 443.544 GLOSSARY AND INDEX. Persistent: remaining, as the leaves of evergreens through the winter, 172; and the calyx, &c. of many plants until the fruit is formed, 279. Personate: masked ; 278, fig. 459, 460. Pet'tuse: having slits or holes. Pdrulate: having pdrulce or bud-scales. Peruvian Bark, 432. Petal: a leaf of the corolla, 222. Petaline, or petaloid: petal-like, in color and texture, 260. Pdiolar : borne on the petiole. Petiolate, petioled: having a petiole. Petiole: leafstalk, 145, 170. Peiidlulate: the leaflet stalked, 164. Pe'tiolule: the stalk of a leaflet, 164. Phcenogamous, or phanerogamous: hav- ing manifest flowers, 69. Phsenogamous or Phanerogamous Plants, 69, 369, 375. Phalanges: bundles of adelphous or clustered stamens. Phoranthium: the receptacle of Com- posite. Phrymacese, 450. PhjcOlogg: same as Algology. Phylla: leaves, 274. -phyllous: leaved, as 3-phyllous} three-leaved, &c. Phyllodineous: bearing or resembling a Phyllddium: a dilated petiole taking the place of a blade, 170. Phyllotaxis, or phyllotdxy, 133. Physiological Botany, 14, 17. Phytelephanteae, 485. Phytdgraphy: descriptive Botany. Phytolaccaeece, 463. Phytdlogy: Botany in general. Phyton: a simple plant-individual, or plant-element, 96. Phytdtomy: vegetable anatomy, 14. Pileate, pileiform: like a cap or Pileus, 507. Pileorhiza: the cap of a root, as found in some aquatic plants; fig. 102. Piliferous: bearing or tipped with hairs O'*')-. Pilose: hairy, as distinguished from woolly or downy; i. c. distinct and straight, but not rigid hairs. Pilosity: hairiness. Pimento, 418. Pine-apple, 492. Piney Tallow, 400. Pink-root, 435. Pinna: one of the primary divisions of a piunately compound leaf, 164. Pinnate, pinnated: a compound leaf with leaflets arranged along the sides of a common petiole; 163, fig. 288-290. Pinnately cleft, lobed, parted, &c., 160. Pinnately 3-plurifoliolate, &c., 164. Pinnately veined, 155, 160. Pinndtifid: pinnately cleft; fig. 261. Pinnatisect: pinnately divided; fig. 263. Pinnule: a secondary division of a pin- nately compound leaf. Piperacese, 469. Pipeline, 469. Pisiform: pea-shaped. Pistachio-nut, 406. Pistil: the ovule-bearing organ of a flower, 223, 287. Pistillate : furnished with pistils, or pis- tils only, 261. Pistillidium, 337. Pitch, 480. Pitchers: see Ascidium ; 169, 387, fig. 299-301. Pitcher-shaped: campanulate or tubular, but with a narrower mouth. Pith, 118. Pits, 37. Pitted: marked with small depressions. Pitted tissue, 45. Placdnta: the place or part of the ovary which bears the ovules or seeds, 289. Placentation: the arrangement of pla- centas. Placentiferous: bearing the placentae. Placentform : nearly the same as quoit- shaped. Plaited: see Plicate, 273. Plane: flat. Plantaginacese, 444. Platanacete, 476. Platycarpous: broad-fruited. Pleio-, in Greek derivatives : full of, or many; as Pleiospermous : many-seeded, &c. Pleurenchyma : woody tissue, 41. Pleurorhizal: embryo with the radicle lying against the side or edge of the cotyledons; same as accum- bent. Plicate, plicative: thrown into longitu- dinal plaits (plicie); folded, 144, 273. Plum, 415. Plumbaginacete, 444. Plumose: feathered ; when bristles, &c. have fine hairs on each side like the plume of a feather, as the pap- pus of Thistles, &e.; fig. 890. Plumule: the bud or growing point of the embryo above the cotyledons, 71,324. Pluri-, in words of Latin origin: sev- eral, at least more than one ; as Pluriflorous: several-flowered. Plurifiliolate: bearing several leaflets.GLOSSARY AND INDEX. 545 Plurildcular: several-celletl. Poculiform: deep cup-shaped. Pod: a dry dehiscent fruit, 315. Podosperm: seed-stalk, 297. Podostemaceae, 471. Pointless: see Mutic&us. Pointletted: same as Apiculate. Polemoniaceaa, 453. Pollen : the contents of the anther, 223, 285. Pollen-tube, 286, 302. Pollinia : pollen-masses, 286, 489. Pollimferous: bearing pollen. Poly-, in Greek compounds : numerous. Polyadelphia, 513. Polyadelphous: having the filaments in several sets, 280. Polyandria, 512. Polyandrous : with numerous stamens, especially when inserted on the receptacle, 242, 280. Polyanthous: many-flowered. Polycarpic: fruiting many times, i. e. year after year; perennial. 101. Polycdphalous : bearing many heads. Pplycladous: much-branched. Polycdccous: of several cocci. Polucoti/ledonous: having several cotyle- dons, 79, 326. Polygalaceic, 411. Polygamia, 513, 515. Polygamous; having both perfect and separated flowers, 262. Polygonaceas, 465. Polygonous: many-angled. Polygyna, 515. Polygynous: with numerous pistils or styles, 287. Polymerous: formed of many members. Polymdrphous : various in form. Polypetahus: having distinct petals, 249, 275. Pdlyphore: a common receptacle of many carpels, as in Strawberry. Polyphyllous: many-leaved or several- leaved, 275. Polypodiacete, or Polypodinese, 501. Polyrhizal: many-rooted. Polgsdpalous: of two or more distinct sepals, 249, 275. Polyspe'rmous: many-seeded. Polysporous: containing many spores. Polystemonous : with many stamens. Pome: an apple, pear, &c., 312. PomeEe, or Pomaceaj, 416. Pomegranate, 418. Pomiferous: pome-bearing. Pomdlogy: the department of Botany relating to fruits. Pontederiaccas, 495. Porose: porous, having holes, Portulacacere, 396. Posterior (in the flower) : next the com- mon axis, 237. Pdsticous: same as extrorse. Potato, 456, 455. Pouch: see Silicle, 317. Praifloration: same as JEstivation, 269. Prcefoliation: same as Vernation, 143. Prcemdrse: as if bitten off. Prickly: armed with Prickles, 52. Primine: outer coat of the ovule, 298. Primdrdial leaves, 143 ; utricle, 26. Primulacese, 443. Prismatic, prismatical: with flat longi- tudinal faces, separated by angles. Process: any projection from a surface. Procumbent: lying along the ground, 102. Produced: prolonged or extended. Pro-embryo, 338. Proliferous (bearing offspring): develop- ing new branches, flowers, &c. from the older ones, or from unusual places. Prone: lying face downwards. Proper juices, 57. Prosdnchyma, 41. Prosdnthesis, 236. Prostrate : lying flat on the ground, 102. Proteaceas, 468. Proteine, 27, 53, 57, 196. Proteranthous: where flowers are pro- duced earlier than the leaves. Protlidllus, or protothallus, 338. Protophytes : Algse and Lichenes are so called. Prdtoplasm, 26, 53, 57, 196. Priiinate, pruinose: as if frosted over; Pr uni form: plum-shaped. Pseudo-bulb: a kind of corm, as of epi- phytic Orchidacese. Pseudo-parasitic: same as epiphytic. Pterocarpous: wing-fruited. Pteroid: wing-like. Pubescent: clothed with soft or downy hairs, or pubescence. Pugidniform : dagger-shaped. Pulque, 491. Pulse, 413. Pulvei'aceous, or pulverulent: dusty or powdery on the surface. Pulvinate: cushioned. Pulvinus (a cushion) : an enlargement at or below the base of a leafstalk. Pumpkin, 423. Punctate: dotted as if by punctures. Pungent: pricking ; rigid-pointed. Pustulate: blistered. Putamen: the stone or shell of a drupe, 310,312. Pyrence: the stones of small drupes;, same as nucules. 46*546 GLOSSARY AND INDEX. Pyriform: pear-shaped. Pyroleae, or Pyrolaceae, 440. Pyxidate: furnished with a lid, like a Pyxidium, or pyxis: a pod opening by a lid; 317, fig. 575, 588, 950, &c. Quadrangular: four-angled. Quadri-, in Latin compounds : four. Quadrifurious: in four vertical ranks. Quadri fid: four-cleft. Quadrifoliate: four-leaved. Quadrifijliolate : of four leaflets. Quadri jugate: four-paired. Quadripartite: four-parted. Quandang-nuts, 460. Quassia, 405. Quaternary : consisting of four, 239. Quaternary products, 53, 57, 196. Quaternate: in fours. Quercitron, Qucrcine, 476. Quin-, in Latin compounds: five in number. Quinary : consisting of five, 234, 239. Quinate: in fives. Quince, 416. Quincuncial: five-ranked; in a quincunx, 135,270. Quinine, Quinia, 57, 433. Quinquefarious: five-ranked. Quinquefoliate: five-leaved. Quinquefoliolate: of five leaflets. Quinquelocular: five-celled. Quinquina Bark, 433. Quintuple : dividing into five parts. Quintuple-ribbed, or Quint upli-nerved, 156. Race: a variety perpetuable by seed, 356. Raceme: an indefinite inflorescence with single pedicellcd flowers arranged along a prolonged axis; 211, fig. 307. Racemifei'ous: bearing racemes. RacCmiform: resembling a raceme. Racemose: bearing or resembling ra- cemes. Rachis: see Rhachis. Radial: belonging to the border or ray. Radiate, radiant: spreading from or arranged around a centre; having- rays. Rddiated-reined, 156. ■ Radical: relating to the root {radix). Radical leaves: those apparently spring- ing from the root, 143. Radicant: rooting. Radicel: a diminutive root or rootlet. Radicifldrous: flowering from the root, or apparently so. Radiciform: appearing like a root. Radicle: a diminutive root; the part of an embryo below 'the cotyledons, 71, 324. Radii: rays. Rafflesiacese, 463. Ramal, or rameal: relating to branches, 143. Ramdnta, raments: thin chaffy scales in place of hairs. Ramentaceous: bearing raments, as the stalks of many Ferns. Ramification, 97. Ramifiorous: flowering on the branches. Ramose: bearing branches (rami) ; branchy. Rdmulose: bearing many branchlets (ramuli). Ranunculaceae, 380. Raphe: see Rhaphe. Raphides : crystals in plants, 59 Rare: thinly set; sparse or few. Raspberry. 416. Ray: the marginal flowers of a head, when different from the rest, 436; the branches of an umbel, &c. Ray-flower, 436. Receptacle of the flower, 224, 266. Receptacle of inflorescence, 211, 215. Recess: same as sinus. Reclinate, reclined: falling or turned downwards. Rectinerved: parallel-veined. Rectise'rial: in rectilinear ranks, 141. Recurved: curved, especially curved backwards. Reduplicate, reduplicative, 273. Reflexed: bent downwards or back- wards. Refracted: suddenly bent backwards. Regular: the members alike in size and form, 239, 277. Re'niform: kidney-shaped ; same as round-heart-shaped, but the breadth greater than the length ; fig. 245. Repdnd: bowed, the margin obscurely sinuate, 159, fig. 257. Re'pent: same as creeping, 102. Replicate: folded back. Re'plum (a door-case) ; the frame-like placentae of Papaveracese, &c. from which the valves of the pod fall away in dehiscence. Reproduction, 20,21, 61; — in Cryptoga- mous plants, 330. Reproductive organs, 70. Reptant: same as repent. Rescdacefe, 391. Resins, 195. Respiration, 178,199, 202. Restiaceai, 496. Resupinate: underside up, or having that appearance. Reticulated: netted, 154.GLOSSARY AND INDEX. 547 Reticulated ducts, 46. Retinaculum: a stay or holdfast: ap- plied to the processes bearing the seeds of Acanthaceae, &c. Rdtinerved: same as reticulated. Retrocurved: same as recurved. Retroflexed: same as reflexed. Retrofracted: same as refracted. Retrorse: backwards, directed back- wards. Retrovdrted: turned upside down. Reluse: slightly notched at a rounded apex ; 162, fig. 272. Revolute, revolutive: rolled backwards, 144. Rhachis (back-bone) : the axis of a spike, &c., 211. Rhamnaceae, 408. Rhaphe of an ovule or seed, 299, fig. 529, r. Rhatany, 412. Rhizdnthous: root-flowered; as when a flower (like Rafflesia, fig. 150), or a cluster of flowers, &c. without green foliage (like Beech-drops), is parasitic by what answers to roots, on some foster plant. Rhizocdrpous (root-fruiting) : having a perennial root. Rhizdma: rootstock, 106. Rhizomorphous: root-like. Rhizophoraceae, 419. Rhodospermeae, 509. Rhombic: rhoipb-shaped. Rhomboidal: approaching a rhomboid in form. Rhubarb, 466. Rib: a strong nerve or part of the frame- work of a leaf, &c , 145, 155. Ribbed: when strong nerves or ribs run lengthwise through a leaf, &c. Ricciaceae, 504. Rice, 498. Rimose: with chinks or clefts (rimee). Ring of Perns, 501; of Mosses, 503. Ringent: grinning; when a bilabiate corolla is open, 278. Riparious: along water-courses. Root, 79. Root-hairs, 81. Rootlet: a very small root, or ultimate branch of a root. Rootstock: same as rhizoma, 106. Rosaceae, 415. Rosaceous: rose-like, 276. Rdstellate: diminutive of rostrate. Rostdllum: a little beak. Rdstrate: beaked, bearing a Rostrum : a beak-like projection. Rdsidar, or rosulate: shaped like a ro- sette. Rotate; wheel-shaped; 278, fig. 454. Rotation in cells : see Cyclosis, 31. Rotund, rotundate: of rounded outline. Rough: see Scabrid or Scabrous. Rubescent, rubicund: reddish or rosy. Rubiaceas, 431. Rubiginose : rusty reddish. Ruderal: growing in rubbish. Rudimentary: imperfectly or incom- pletely developed. Rufescent: approaching to Rufous: brown-red. Rugose: wrinkled (ruga, a wrinkle). Ruminated (albumen) : penetrated with holes or channels; 323, 383, fig. 658. Runcinate: saw-toothed, the teeth turned backwards, 161, fig. 279. Runner, 102. Running, 102. Rupestrine: growing naturally on rocks. Ruptile: bursting irregularly. Rusty: see Ferrugineous. Rutaceae, 405. Rye, 498. Sdbuline, or sdbulose: growing in sand. Saccate, sacciform : sac-shaped, 278. Sac of the amnios, 304. Saffron, 491, 437. Sagittate: arrow-headed, or arrow- shaped ; lanceolate with a lobe at the base on each side pointing backwards ; fig. 252. Sago, 481, 485. Salep, 489, Salicacete, or Salicini®, 478. Salicine, 478. Saline, salsuginous: growing in salt places, or impregnated with salt. Salver-shaped: tubular and the border spreading flat at right angles to the tube ; 277, fig. 457. Salviniegc, 502. Samara : a key or winged indehiscent fruit, 314, fig. 577, 578. Samaroid: resembling a samara. Sambuccas, 431. Sandal-wood, 414, 469. Santalacese, 468. Sap, 53, 190. Sapindacese, 409. Sap-green, 408. Sapodilla Plum, 443. Sapotacese, 443. Sap-wood, 35, 124, 126. Sdrcocaip: the fleshy part of a drupe, 310, 312. Sarmentdceous: bearing or resembling Sarments : runners or long and flexible branches. Sarraceniacese, 387. Sarsaparilla, 493.548 GLOSSARY AND INDEX. Saururacese, 469. Saw-toothed: same as Serrate. Sdxatile: living in rocky places. Saxifragacese, 424. Scabrate, scabrid, or scabrous: rough to the touch. Scalariform: ladder-shaped, or barred. Scalarifoim ducts, 46. Scales : any thin scale-like appendages ; usually degenerated leaves, 105. Scalloped: same as Crenate. Scaly: furnished with scales, 95, 191. Seammony, 455. Scandent: climbing. Scape: a ' flower-stalk rising from the ground or near it, 220. Scapiform, or scapoid: resembling a scape. Scar: see Leaf-scar and Hilum. Scariose, or scarious: thin, dry, and membranaceous. Scattered: either sparse, or without ap- parent symmetry of arrangement. Schizandrese, 382. Scion: a shoot, especially one used for grafting. Sciuroid: like a squirrel's tail. Scleranthese, 396. Sc/erogen : same as Lignine, 36. ScObiform, or scobicular: like sawdust. Scorpioid: coiled round like a scorpion, as the branches of the cyme of Heliotrope. Scrobiculate: pitted. Scrophulariacese, 448. Scrdt/foi'in: pouch-shaped. Scurf: minute or bran-like scales on the epidermis, 52. Scutate, scutiform: shield-shaped. Scutd/liform : shaped like a platter (scu- teila). Secretions, 51. Seclile: divided into portions. Secund: all turned to one side of an axis. Secundine: the second coat of an ovule, 298. Seed, 70, 320. Seed-vessel, 308. Segment: one of the divisions or lobes of a leaf or other organ; 159, 275. Segregate.- kept separate. Semi-, in Latin compounds : half. Semi-adhei'ent: the lower half adherent. Semi-amplexicaul: half-clasping. Semicordate: half heart-shaped (divided lengthwise). Semi-double: half-double. Semi-floscular; when the flowers of a head are ligulate. Semilunar, or semilunate: like a crescent or half-moon. Seminal: relating or belonging to the seed. Seminiferous: seed-bearing. Semiorbicular: half-round. Semioval: half of an oval, and Semiovate: half of an ovate figure, di- vided longitudinally. Semisagittate : arrow-headed with one lobe wanting. Semiseptate : a partition reaching partly across. Semiterete: half-cylindrical. Sempervirent: evergreen. Senna, 414. Sensitive plants, 345. Sepal: a calyx-lcaf, 222. Sepaline, sepalous: relating to sepals. Se'pa/oid: resembling a sepal. Separated flowers: the stamens and the pistils occupying separate blossoms, 261. Sef>taie: with a partition (septum). Septicidal, or septicide: dehiscent through the partitions, i. e. by the lines of junction; 316, fig. 582, 584. Sephferous: bearing a partition. Septifragal: where the valves separate from the dissepiments, 317. Septum (plural septa) : a partition of any kind, 316. Serial, or seriate: arranged in rows. Sericeous: silky. Series: rank. Serotinous: flowering or fruiting late. Serrate: beset with teeth pointing for- wards, like those of a saw, 159, fig. 254. Sdrratures: the teeth of a serrate body. Serrulate: Serrate with fine teeth. Scsamese, 447. Sdssile (sitting) : not stalked, 145, 211, 281. Seta: a bristle, or bristle-like body, 52. Setaceous, set iform: like a bristle. Setigerous: bristle-bearing. Setose: bearing or abounding with bris- tles. Sdtula: diminutive of Seta. Se'tulose: bearing minute bristles. Sex: six; as in Sexangular: six-angled. Sexfarious: six-rowed. Sexpartite: six-parted, &c. Shaggy: see Villous. Sheath: a tubular body, enclosing or surrounding some other; as the base of the leaves of Grasses ; 170, fig. 237. Sheathing: forming a sheath; see Va- ginate. Shields: see Apothecia, 506.GLOSSARY AND INDEX. 549 Shield-shaped: see Peltate, 158, fig. 248, 681. Shoot: any fresh branch. Shrub, shrubby, 101. Sigillate: as if marked with the impres- sion of a seal, as in Solomon’s Seal, fig. 168. Sigmoid: curved like the Greek sigma, or letter S. Signs used in Botany, 517. Silenecc, 395. Silicle: a pouch, or short pod of Cru- ciferse, 317, fig. 703. Siliculosa, 515. Siliculose: having or resembling a sili- cle. Silique: a long pod of Cruciferse ; 317, fig. 589. Siliquosa, 516. Siliquose: like a silique. Silk-cotton, 399. Silky: clothed with fine, appressed, and glossy hairs, producing a satiny surface. Silver-berry, 468. Silver-grain, 120. Simarubacese, 405. Simple: of one piece or rank. Simple fruits, 309, 311; leaves, 162; pistil, 288. Sinistrdrse: turned to the left. Sinuate: strongly wavy on the margin, with alternate convexities and con- cavities ; 159, fig. 258. Sinus: a re-entering angle or recess. Slashed: same as Laciniatc. Sleep of plants, 344. Smilacese, 492. Smooth : not pubescent or hairy, or else (and more strictly) not rough. Snake-root, 412, 462. Soap-berry, 410. Solwliferous: bearing shoots (soboles). Social (plants): growing gregariously. Solanacece, 456. Solitary: single ; alone. Soluble: separating into parts. Sorddiate : bearing little patches on the surface. Sorose : heaped, or bearing. Sordsis: a fleshy multiple fruit, like a mulberry. Son (sing, sorus): heaps or patches, as those of the spore-cases of most Ferns, called in English fruit-dots, 501. Spadiceous: bearing a Spadix: a sort of fleshy spike, 213. Span : the length spanned between the thumb and little finger; seven or eight inches. Sparse: scattered and generally scanty. Spathdceous : bearing a Spathe: the enveloping bract of a spa- dix, 213. Spdthulate, or spatulate: shaped like a druggist’s spatula. Special directions, 341. Species, 19, 354. Specifc: relating to species. Spdrmaphore: a name for the placenta, or the funiculus of the seed. Spermatozoids, 334. Spermic, or spermous: relating to the seed. Spermodemi: the outer seed-coat, 320. Spicate: relating to or disposed in a spike. Spiciform: spike-like. Spicula: a spikelet. Spike: a prolonged indefinite inflo- rescence with sessile flowers, 212. Spikelet: a diminutiye or secondary spike; the ultimate flower-clusters of Grasses. Spikenard, 435. Spindle-shaped, 84, fig. 138. Spine, 104, 167. Spinescent: tipped with a spine, 104. Spinose: spiny, 104. Spinulose: bearing diminutive spines. Spiral: as if wound round an axis. Spiral arrangement of leaves, 134. Spiral markings on cells, 39. Spiral vessels or ducts, 46. Spirese, 416. Spithamceous: a span high. Spdngioles, or spongelets, 80. Spongy: of the texture of sponge. Spontaneous movements, 340, 347. Sporadic: widely dispersed. Spordngium: a spore-case, 337, 500, &c. Spore: the body in Cryptogamous plants which answers to the seed in the Phtenogamous, 61, 70, 331. Spore-case, 337. Sporiferous: spore-bearing. Spdrocarp: a kind of sporangium, 502. Sports, 356. Spdrule: a spore, or small spore. Sporuliferous: bearing sporules. Spumescent, spumose: froth-like. Spur: any tubular projection, 278. Spurred: bearing a spur, 278. Squamate, squamose, squamiferous : fur- nished with scales (squamce). Squamellate: with or resembling minute and narrow scales (squameUce, 497). -Squdmiform: scale-shaped. Squdmuliform: like a small scale, or Squdmula, 497. Squamulose: covered with small scales. Squarrose: where scales, small leaves, or other bodies, spread widely from550 GLOSSARY AND INDEX. the axis on which they are crowded. Squdrrulose: diminutive of Squarrose. Squash, 423. Squills, 493. Stalked: furnished with a stalk, stem, or any lengthened support. Stalked ylands, 52. Stalklet: a diminutive or secondary stalk. Stamen: the fertilizing organ of a flow- er, 223. Staminate, or stamineal: relating to the stamens. A staminate flower has no pistils, 261. Staminiferous: bearing stamens. Staminddium: an altered and sterile sta- men, or a body occupying the place of a stamen. Standard: the posterior petal of a pa- pilionaceous corolla, 253. Staphyleacece, 409. Star-apple, 443. Starch, 54,193. Staticeai, 445. % Station: the locality or kind of situa- tion in which a olant naturally grows. Stellatee, 432. Stellate: starry, star-shaped; arranged in rays, like the points of a star. Stellate hairs, 52. Stdllulaie: diminutive of Stellate. Stem, 91. Stemless: having no obvious stem, 91. Stemlet: a diminutive stem ; the first internode of the plumule. Sterculiacese, 399. Sterigma: the adherent base or down- ward prolongation of a decurrent leaf. Sterile: barren. Sterile flower: one having no pistils, 261. Sterile stamens or fllaments: those des- titute of anthers, or with the anther imperfect, 281. Stigma: the part of a pistil which re- ceives the pollen, 223, 287. Stigmdtic, or stigmatose: relating to or bearing the stigma. Stings, stinging hairs, 52. Stipe (stipes): a stalk of an ovary (267), of a Mushroom (507), and the leaf-stalk of a Fern. Stipel: the stipule of a leaflet; 171, fig. 286. Stipellate: furnished with stipels, 171. Stipitate: having a stipe, 267. Stipitiform : shaped like a stipe. Stipuldceous, stipular: belonging to or resembling stipules. Stipulate, stipuled: possessing stipules, 171. Stipule: an accessory part of a leaf, one on each side of the base, 145, 170. Stock, 355. Stole, stolon: a rooting branch, 102. Stoloniferous: bearing stolons. Stoma (plural stdmata), stomate: a breathing-pore, 52,150. Stomatiferous: bearing stomates. Stone: the endocarp of a drupe. Stone-fruit, 312. Stool: the plant from which layers are propagated. Storax, 425, 442. Stramineous: straw-like. Strangulated: irregularly contracted. Strap-shaped: see Ligulate. Stratum: a layer. Strawberry, 416. Striate: marked with longitudinal streaks or furrows {stride). Strict: very straight or close, or very upright. S/rigillose : same as Strigose. Striyose: clothed with sharp and stout close-pressed hairs or scale-like bristles (strigee). Strobilaceous: relating to, or resem- bling a Strdbile : the cone of a Pine, &c., 319. Strobiliferous: bearing strobiles. Strombuliferous: spirally twisted, like a corkscrew or a strombus. Strdphiole: same as a Caruncle, 322. Structural Botany, 14. Strumose: swollen on one side, bearing a struma or wen. Strychnine, 57, 434. Stupose: tow-like. Style: a columnar or slender part of the pistil above the ovary, 223, 287. Styliferous: style-bearing. Styliform: style-shaped. Stylopddium: an enlargement or fleshyt disk at the base of a style, as in Umbelliferas. Styraceae, 442. Sub-, as a prefix, means somewhat, or slightly; as Subacute: somewhat acute. Subclass, 362. Suhcordate ; slightly heart-shaped, &c. Suberose: of a corky texture. Subgenus, 361, 362. Submerged: growing under water. Suborder, 361. Subspecies : a marked variety. Sub tribe, 361. Subterranean: growing beneath the sur- face of the ground.GLOSSARY AND INDEX. 551 Subulate, subuliform: awl-shaped ; nar- row, and tapering to a sharp rigid point, as the leaves of Juniper, &c. 166. Succise: as if cut off at the end. Succose, succulent: juicy. Succubous: the apex of each leaf cov- ered by the base of the next, as in Jungcrmannia. Succulent leaves, 166. Sucker, 102. Suffrutescent: slightly shrubby, 101. Suffnitex: an undershrub. Sujjruticose: low and shrubby, or shrub- by at the base, 101. Sugar, 53, 193, 194. Sulcate: longitudinally grooved. Super-, above; as Super-axillary: above the axil. Superior: above, 252 ; also, on the up- per side of the flower, i. c. next the common axis (237), as, for exam- ple, the vexillum of a papiliona- ceous corolla (fig. 372, a) is the superior petal. Superposed: one above another. Superposition, 248. Supervolute, 274. Supine: lying flat with face upwards. Suppression: obliteration of parts, 239, 255. Supra-, above ; as Supra-axillary: above the axil. Supi'a-decompound: several times com- pounded. Surcidose: producing suckers. Surculus : a sucker, 102. Suspended: hanging from the apex, 297. Suspensor of the embryo, 306. Sutural: relating to the Suture: the seam, or line of opening of a pod, &c., 289. Sword-shaped: a blade with two sharp and nearly parallel edges, tapering to a point, as in Iris, fig. 291. Syconium, or syconus: such a fruit as a fig- . Symmetrical: equal in the number of all the parts, 232, 239. Sympetalous: becoming somewhat mon- opctalous by a junction of the base of the petals with the monadel- phous stamens, as in the Mallow family. Symphyantherous: same as Syngenesious. Symphysis: a growing together of parts. Symphystdmonous: the stamens united. Symplocinese, 443. Syndntherous: united by their anthers; whence Composite have been named Synantheraj, 435. Syncdrpous: formed of two or more united carpels, 290. Si/ncotuledonous: the cotyledons soldered together. Synedral: growing on the angles. Syne'nui: a name for a column of mon- adelphous filaments. Syngenesia, 513. Syngenesious: stamens united by their anthers ; 280, fig. 463. Synonyme: equivalent or superseded names. Syndnymy: what relates to synonymes. System, 365, 366. Systematic Botany, 15, 351. Tabescent: wasting or shrivelling. Tabular: flattened horizontally. Tail: any long and slender terminal appendage. Tail-pointed: tipped with a prolonged and weak acumiuation. Tannin, Tannic Acid, 57. Taper-pointed: same as Acuminate. Tapioca, 472. Tap-root, 84. Tar, 480. Taro, 485. Tawny: dull yellowish, verging to brown. Taxinece, 480. Taxdlogy, or Taxdnomy: the depart- ment of Botany which relates to classification. Tea, 401. Teasels, 435. Teeth of calyx, corolla, &c., 275; of leaves, 159. Tegmen: the inner seed-coat, 321. Tendril, 102, 167. Tepal: a name proposed for a leaf or part of the perianth when it is un- certain whether it belongs to the calyx or the corolla. Teratology: morphology applied to monstrous states. Tercine: a third coat of the ovule. Terete: long and round, i. e. the cross- section circular. Tergeminate: thrice twin. Terminal: belonging or relating to the summit. Terminology: the same as Glossology, 15* Ternary: consisting of three, 239. Ternary products, 53. Ternate: in threes. Ternstroemiaceee, 401. Tessellated: in checker-work. Testa: the outer seed-coat, 320. Testaceous: brownish-yellow, like un- glazed earthen-ware.552 GLOSSARY AND INDEX. Tetra-j in Greek compound words: four. Tetracdrpellary: of four carpels. Tetracamarous: same as Telracdccous: of four cocci. Tetradynamia, 512. Tetradynamous: two of the six stamens shorter than the rest; 281, fig. 407. Tetragonal, or tet.ragonous: four-angled. Tetragynia, 515. Tetraqynous: with four pistils or styles, 287. Tetrdmerous: the parts in fours, 234, 239. Tetrandria, 512. Tetrandrous: with four stamens, 279. Tetrapetalous: with four petals, 276. Tetraphyllous: four-leaved, 275. Tetraquetrous: quadrangular, with very sharp and salient angles. Tetrasdpalous: with four sepals, 274. Tetrastichous: with four vertical ranks. Thalamifldrous: with the stamens, &c. inserted in the receptacle, or Thdlamus: the receptacle of a flower. Thallophytes, 371, 505. Thallus, 67, 371, 505. Theca: an anther-cell, 281; or a spore- case, 499, 500. Thdcaphore: same as Gynophore, 267. Thread-shaped: see Filiform, 166. Throat: the orifice of a tubular organ, 275, 276. Thorn, 104. Thyrse, or thyrsus: a thick panicle, 217. Thyrsoid: like a thyrse. Thymelacece, 467 Tieute, 434. Tiliaceae, 399. Tissue: the fabric of plants, 22. Tobacco, 456. Tomato, 456. Tonientose: clothed with Tomdntum: a close and matted down or wool. Tongue-shaped: long, fleshy, nearly flat, and rouuded at the end. Tonka-bean, 414. Tooth: any short and narrow projec- tion. Toothed: same as Dentate; beset with teetli which on the leaf do not point forwards ; 159, fig. 255. Top-shaped: inversely conical. Torose: a cylindrical body swollen at in- tervals. Tortuous: bent in different directions. Tdrulose: somewhat torose. Torus: the receptacle of the flower, 224. Trabeculate: cross-barrcd. Trachea: a spiral vessel or duct, 46. Trachdnchyma, 46. Trapezoid, or trapeziform: unsymmet- rically four-sided, like a trape- zium. Tree, 101. Tri-, in compound words : three; as Triadelphous: having the filaments in three sets, 280. Triandria, 512. Tridndrous: with three stamens, 279. Triangular: three-angled. Trianthous: three-flowered. Tribe, 361. Tricdrpellary: of three carpels. Tricdrpous: with three ovaries. Tricdphalous: three-headed. Trichdtomous : branched into threes. Tricdccous: of three cocci. Tricuspidate: three-pointed. Tride'ntate: three-toothed. Triennial: lasting three years. Trifarious: in three vertical ranks. TriJid: three-cleft; 159, fig. 265. Trifdliate: three-leaved. Trifdliolate: of three leaflets. Trifurcate: three-forked. Tngamous: having three sorts of flowers. Trigonal, or trigonous: three-angled. Trigynia, 515. Tngynous: with three pistils or styles, ^ 287. Trijugate: three-paired. Trilateral: three-sided. Trilliaceae, 493. Tnlobate: three-lobed. Trildcular: threc-cellcd. Tnmerous: the parts in threes; 234, 239, fig. 353. Trine'rcate: thrcc-ncrvcd. Trinddal: of three nodes or joints. Tricecia, 516. Tricccious, or trioicous: having stami- nate, pistillate, and perfect flowers on three different plants. Triovulate: having three ovules. Tripartible: capable of splitting into three. Tripartite: three-parted. Tripe'talous: of three petals, 276. Triphy/lous: three-leaved, 275. Tripinnate: thrice pinnate, 164. Tripinndtijid: thrice pinnatifid, 161. Triple-ribbed, or nerved: same as Tripli-nerved, 155. Tnpterous: three-winged. Triquetrous: with three salient angles. Trisepalous: of three sepals, 274. Trisdrial, or triseriate: in three horizon- tal ranks. Tristichous: in three vertical ranks, 134. Tristigmdtic: with three stigmas. Tristylous: with three styles.GLOSSARY AND INDEX. 553 Trisiilcate; three-grooved. TriUmate: thrice ternate, 164. Trivial name: the popular name; or the specific name. Trochlear: pulley-shaped. Tropamlacese, 404. Trophosperm: the placenta. Tropical: growing near or between the tropics. Trumpet-shaped: tubular, with the sum- mit dilated. Truncate: as if cut off at the end; 162, fig. 271. Trunk: a main stem. Tube: the portion of a calyx, corolla, &c. formed by the union of the sepals, petals, &c., 275. Tuber: a short and thickened subterra- nean branch, 107. Tubercle: a small tuber, or an excres- cence. Tuberclecl: bearing excrescences. Tuberiferous: bearing tubers. Tuberous: tuber-like; 85, fig. 139. Tubulose, tubular : having a tube, or tube-shaped, as the corolla of Trum- pet Honeysuckle, &c., 277. Tubuliflor®, 436. Tumid: somewhat inflated. Tunicate; having an acccssoiy covering (tunic). Tunicated bulb, 109. Turbinate: top-shaped. Turio, turions: the early state of a suck- er or subterranean shoot, as an Asparagus-shoot, 95. Turmeric, 490. Turneraceas, 422. Turnip-shaped: see Napiform, 84. Turnsole, 473. Turpentine, 57, 480. Twin: in pairs. Twining: winding spirally round a sup- port, 102. Two-lipped, 255. Type: the pattern or ideal plan, 231, 238. Typhaceas, 485. Typical: representing the type or plan. Uliginose: growing in marshes. Ulmaceae, 474. Ulmine, Ulmic Acid, 57. Umbel: an umbrella-shaped inflores- , cence, 212. Umbellate, umbelliform: in umbels. Umbellet: a secondary or partial um- bel, 216. Umbelliferse, 425. Umbelliferous: bearing umbels. Umbilicate: depressed in the centre, like the navel. Umbilicus: the hilum of a seed ; a cen- , tral depression. Umbonate: bearing an umbo or boss, a central projection. Umbrdculiform: umbrella-shaped. Unarmed: destitute of prickles, spines, &c. Uncate: hooked. Unciform, or uncinate: hooked. Undate, or undulate: wavy. Undershiub, 101. Unequally pinnate: same as impari-pin- nate, 163. Unguiculate: furnished with a claw (un- guis), as the petals of Saponaria, 276, fig. 449, &c. Uni-, in Latin compounds : one. Unicellular: one-cellcd, 61. Unifldrous: one-flowered. Unifdliate: one-leaved. Unifdliolate: with one leaflet. Unijugate: of only one pair, 164. Umlabiate: one-lipped. Unilateral: one-sided: either all dis- posed on one side of an axis, or turned to one side. Unildcular: one-celled. Unindrvate: one-nerved. Unidvulate: one-ovulcd. Unipetalous: having only one petal, as in Amorpha, fig. 395. Unisdrial, or unisdriate: in one horizon- tal row or whorl. Unisexual: having stamens only or pis- , tils only, 261. Univalved: of one piece ; onc-valved. Universal: same as General. Upas, 475. Urceolate: pitcher-shaped or urn-shaped; i. e. hollow and contracted at the mouth. Urticaceas, 473. Utricle : a small bladdery fruit, 314. Utricular: bladder-like. Utriculariaceae, or UtriculaUneaj: same as Lcntibulaceaj, 445. Utriculiform : shaped like a little bottle. Utriculose: bearing utriculi, or bladders. Uvularieae, 494. Vaccinieee, or Vacciniacese, 439. Vagina: the sheath of a leaf, &c. Vaginant: sheathing. Vaginate: sheathed. Vag'mula: a little sheath, as that around the sporangium of Peat Moss. Vaginulate : with a vaginula. Vague: in no definite order or direction. Valerian, 434. Valerianacere, 434. Valldculce: the intervals between the ridges of the fruit of Umbelliferse. 47554 GLOSSARY AND INDEX. Valvate or vdlvular aestivation, &c.: where the parts meet by their edges without overlapping, 144, 273. Valve: a door, or portion into which a pod, &c. separates in dehiscence; also a piece or leaf of a spathe, &c. Valued: opening by valves. Vanilla, 489. Variegated: having one or two colors disposed in patches. Varieties, 355. Vascular ; relating to or furnished with vessels. Vascular Plants, 68. Vascular or vasij'orm tissue, 40, 45. Vasculum: same as Ascidium. Vegetable Ivory, 484. Vegetable Physiology and Anatomy, 14. Veil: see Calyptra. Veined: furnished with slender vascular or woody bundles, especially with branching ones, or Veins, 145, 155. Veinless: destitute of apparent veins. Veinlets: the smaller ramifications of veins, 155. Velate: veiled. Velutinous: velvety ; covered with very fine and close soft hairs, so that the surface resembles velvet to the touch. Venation: the mode of veining, 154. Venose: veiny ; abounding in veins. Ventral: relating to the inner side of a simple pistil, viz. that next the axis. Ventral suture: the inner suture, 289. Ventricose: big-bellied ; swelling out. Venlriculose: somewhat ventricose. Vdnulose: abounding in veinlets. Veratria, 494. Verbenaceaj, 449. Vermicular: worm-like, in shape or ap- pearance. Vernal: belonging to spring. Vernation: the disposition of leaves in the bud, 143. Vernicose: varnished. V&Tucose; warty. Vdrruculose: studded with little warts. Versatile: swinging to and fro; 282, fig. 471. Vertex: the summit. Vertical: perpendicular, lengthwise. Vertical leaves, 165. Vertical tissue or system, 45, 50, 112. Verticil, or verticel: a whorl, 92, 134. Verticil!aster: the pair of dense cymes forming an apparent verticil in most Labiatre, 221. Vei'tfcillate: whorled, 133, 142, 221. Vesicle: a little bladder. Vesicular: as if composed of little blad- ders. Vespertine: appearing or expanding in the early evening. Vessels, 40. Vexillcmj aestivation, 271. Ve'xillarrj: pertaining to the Vexillum : the standard of a papiliona- ceous corolla; 253, fig. 392, a. Villose, or villous : shaggywith long and soft hairs, or villosity. . Vimineous: bearing or resembling long and flexible twigs, like wicker. Vine: any trailing, climbing, or twining stem. The Vine, originally, is the Grape-vine. Violaceae, or Violariese, 392. Virescent: somewhat green (virens). Virgate: twig-like; wand-like. Viridescent: same as Virescent. Viscid, viscous: sticky from a tena- cious secretion. Vitaceae, 407. Vitdilus: the thickened embryo-sac per- sistent in the seed, as in Saurums and Brasenia. Viticulose: producing small suckers or stolons (viticulce). Vittce (fillets): the oil-receptacles of the fruit of Umbelliferae, 426. Vittate: bearing vittse: marked with longitudinal stripes or fillets, 426. Viviparous: germinating from the seed (330), or sprouting from a bulb, &c., while still attached to the parent plant. Voluble: twining, 102. Volute: rolled up. Volva: the wrapper of Fungi, 507. Walnut, 476. Wavy: see Undulate. Wax, 56. Waxy: resembling beeswax in appear- ance or consistence. Wedge-shaped: see Cuneate. Wheat, 498. Wheel-shaped: a corolla or calyx with a veiy short tube and a flat- spreading border; 278, fig. 454. Whorl :* a set of organs arranged in a circle round an axis, 92, 134, 221. Whorled: disposed in whorls. Whortleberry, 439. Wild: growing spontaneously. Wing: any membranous expansion. Also the two side petals of a pa- pilionaceous corolla; 253, fig. 392, b.GLOSSARY AND INDEX. 555 Winged: provided with wings. Wintered (or Winteraceae), 381. Winter’s Bark, 381. Withering: see Marcescent. Wood, 119. Woody tissue or fibre, 40. Woolly: clothed with long and curling, or matted, soft hairs or wool. Worm-seed, 465. Xyridaceee, 496. Yam, 492. Zanthoxylacece, or Zanthoxylece, 406. Zingiberaceas, 489. Zoospores: free-moving spores of cer- tain Algte; 336, fig. 637, 644. Zygophyllacese, 404.arSSSsi: spp iSBSgS; siaiSK; [ra^afe* E&3tS~rt££ ':!L;;^ ^ffyya; • iiSi: » ■*T^i^''ir $|g|