rapa es ant ena estes iS eats BE eros Bree nee eS fe eet : 2 espa REGUS Snecetoerics S ae see cae ce : a ‘i ae Be BOS eons eae eee sald eal Sees = entacenien ee Sores See Sa DAP NL aS LI Py VEY re Ao % r mene ens eee Seas = Sees : : = s ct = eee ae oe Siete Cornell University Library OF THE Hew Work State College of Agriculture 584 Cornell University Libra “haa ale ae ee Ne PN ee Pi Pe a rr ae ar me eer re eer ia Se * a 2 7ere S.e09)e Cele e le ee ek ae 5.609 ec seen e SF >) CHD TP & 5 ~-SOenaeee xr eseneee x > ae Pe ee ee eee ee Fe re els ere rm es Pree: G2 Or G+ ~ 82 Oh SY + 82 C+ EC =e ee ee ee ee 65s 6 8 6 pe re Ae re eer e+ een C®@pt¢>86 Se a ae a ae a ©} 6+ ~ 62 ©} } ee ee ae ee ese sear es rae e © 8502) © 6814.0 6) 8 5 2 Sto Fro ek 8 rl ee ee es ®@sSet@ptys ee 09 Al= Fleer ae Sac ae a ee Le ee re Ae re 28 ae ee a ee) a ae a ae Se ae ee oa 09 Al= Fleer ae Sac ae a ee Le ee re Ae re 28 ae ee a ee) : A ele Ca ee re Fe etx oe 8) 6p = pl o0S) s _ wv bs) 8 x SU, EC eee ee ee ; 7 ; 1 2 : A . ; 7 ; 2 : A . ee ee a a . ea ee ee ee ee ee eee PLANTS AND THEIR USES AN INTRODUCTION TO BOTANY BY FREDERICK LEROY SARGENT FORMERLY INSTRUCTOR IN BOTANY IN THE UNIVERSITY OF WISCONSIN AND ASSISTANT IN THE BOTANICAL MUSEUM OF HARVARD UNIVERSITY WITH NUMEROUS ILLUSTRATIONS ma \ i \| ee PAB 3 NEW YORK HENRY HOLT AND COMPANY 1913 No. 4142 Coprricut, 1913, BY HENRY HOLT AND COMPANY PRESS OF T. MOREY & SON QREENFIELD, MASS., U.S. A. PREFACE The main purpose of the book is to show some of the edu- cational possibilities offered by plants of every day use, and at the same time to guide beginners to such general ideas about plants as should form part of a liberal education. There are a number of plants that every one ought to know because of their intimate connection with human welfare. These plants represent all parts of the vegetable kingdom, they are the very ones about which most persons have the greatest desire to learn, and they are mainly the ones which were first studied by mankind. Help the be- ginner, therefore, to learn at the outset as much about these economic plants as he is ready for; then help him to classify them scientifically, and he will be. prepared to appreciate that wider view of the life of plants which inspires botany today. On this plan I have tried to write such a book as I believe would have been most useful to me when I was a beginner. Botany taught by the historical method, as this procedure may be called, not only appeals from the start to the strongest practical incentives, but profits by the student’s knowledge in many other departments, which knowledge it often en- riches. Thus pursued botany also offers an exceptionally fine opportunity for cultivating scientific habits of mind and methods of work. These are sure to economize energy in every intellectual undertaking. The scientific attitude and scientific ways of proceeding control modern progress, and in no better way can one catch the spirit of these than by the scientific study of plants. So closely similar are the needs of all who wish to make a good beginning that it becomes possible for a book like the present to serve many diverse classes of students. The WL iv PREFACE scheme is so elastic that no two classes need follow it in pre- cisely the same way; but may vary the work within wide limits, emphasizing now this aspect, now that, hurrying over one part and dwelling upon another as circumstances shall determine. The text printed in small type may be omitted with younger classes, or with those requiring only a short course. The matter in larger type will then be found to proceed connectedly, and to be in no way harmed by the omissions made. If a still shorter course be desired the class may go through as many topics as there is time for, leaving the rest to be taken up if possible at some future time. What- ever ground has been gone over, if well studied, will then be so much to the good; and since the educationally more im- portant subjects have been treated in the earlier chapters, the student may feel that even a little is worth while. The figures used in this book are mostly copies from various well-known works as indicated by the authors’ names in parenthesis under the figures; the remainder are from original drawings by the writer. Permission has been very kindly granted by Dr. N. L. Britton and Judge Addison Brown to use the figures from their Illustrated Flora. In conclusion, I wish to acknowledge most gratefully the helpful criticisms and suggestions received from teachers and other friends during the progress of the work. Especial thanks are due to Charles W. Swan, M. D., for suggestions regarding medicinal and poisonous plants; to Mr. Henry J. Williams, Mr. George W. Rolfe and Professor Ixenneth L. Mark for help on chemical matters; to Professor G. H. Parker for reading evolutionary parts; to Mr. A. B. Seymour for reading the chapters on cryptogams; and to the botanists of the Harvard Herbarium and University Museum for facilitating my work with books and specimens. Be eS: CaMBRIDGE, MAssACHUSETTS December, 1912 CONTENTS RE RACH. jane diekiterti Aven ae soa a, ates aan naan ase CHAPTER I THE STUDY OF PLANTS 1. Botanical questions. ..... Sather Aeonige see Eero 2. The beginnings of botany... ............... 3. Our dependence upon plants. eta Peet 4. Human needs and the needs of plants. Richins te 5. How plants are named................ eas 6. Early plant names... . . Wane se eae es oon 7. Binomial nomenclature... . .. eee oe ar SiS PECleS eal sd axe Ree uecns mance eA eh se 9. Varieties. ... Ro on ene ata: 10. The genus......... Dae a eR Ter Oh 11. The authority ede RON HS heed Secs ae yeey eee a 12. Plant families and higher groups. oe Patek 13. The departments of botany................ CHAPTER II CEREALS 14. What cereals are. . . ; Ea MR 15. Characteristics of cereals. . eee 16. Importance of grains in ancient times: sche fuaee sc 17. Earliest use of grains. . . Sa s 1835 Oates Anos aaa: Nae So otis 19" Barleyans stecee feu ean Se Se 20 RYCrs ceaes eve ; ‘ ee Dis ILRI Zetec. awa aaehieale Re De eae ea aml a eats D2 RACE icesine sive, aaa ae lee 23. Wheat ; ae : Petar e 24. Buckwheat. ‘ ee ee eee 25. The value of cereals. . aS Wwhnwnyr OoOumaN pare . Water in grains. Ash; .;. . Nutrients. Been . Carbohydrates........ ; : PROCES shes 6 uo secsceem Sh is ere : f SAU esa terse ptaiege eee Pe ene are CONNOOEPWNNR Ree vl 51, 52. 53. 54. § 55. 56. RO ol. 58. 65. 66. CONTENTS CHAPTER III VARIOUS FOOD-PLANTS . Classes of food-plants....... SS NNUS fc ams eal ae Re ee : oe: sbPUSOe hagas eee ieee CES ior: . Earth-vegetables...... . . Herbage-vegetables....... Na ea eee hae) . Fruit-vegetables........ ke Deicke eaten e RE TULL SO ter alee s oe iedal eve reriA mean! ~ Miscellaneous food- produc tS... tig Aare pring tenon ey . Vegetable foods in general. . : . seh os : Food as fuel and building material. : antes . Measures of energy........ Ry Sa eee Selec . Energy of vegetable foods. = UAMONS 2 cian guan dati: 3 Le Aen EAR 5. Food-plants in general. .. . PCR eee eee 5. The primitive centres of agriculture.............. se . Relation between culture-period and native home... ... . The multiplication of varieties. LE Se Ave . How varieties arise... . Artificial selection... CHAPTER IV FLAVORING AND BEVERAGE PLANTS Food-adjuncts. . ... “ ee Spices. .... Sav ory herbs. Aas : ; eT eee tae Miaselledeons condiments. Essences. . . . Non-alcoholic bever rages Phace ARGS Beh ATMS Sb So Oe Alcoholic beverages and stimulants in ge neral....... CHAPTER V MEDICINAL AND POISONOUS PLANTS . Medicines and poisons. .. . 60. . Poisonous drugs....... ‘ F Se aie . Plants poisonous to eat... 2... Bees eas . Plants poisonous to handle. . 64. Non-poisonous drugs. . . . Secateurs ove ibs Poisonous plants in general... 2... . CHAPTER VI INDUSTRIAL PLANTS Uses of industrial plants... . Fibers in general. . 115 116 alley 122 122 123 126 126 127 128 128 137 137 137 146 150 156 162 165 176 192 217 219 999 999 _ CONTENTS Vil PAGE 67. Surface fibers................ PONE ote accra 225 68. Bast fibers... . . Saree alata Sea ee ee ee ema 228 G92Vinxed fibers ss woke anaes nade enna elles S 231 ZO: Pseudo-fbersiy cisaa aon ccrnoeiaeian 1 Saab ene a Bae eranene ore 239 CLeeWOOdy TIDErS ian ce cenn su stivateuis atk Rabe oicraloten ah etre ANE eva 240 (2. Wood in. generale Gym’no-sper’mie < Gr. gymnos, naked; sperma, seed. 3 An’’gi-o-sper’mie < Gr. angion, a case. 4 Sper’ma-toph’’y-ta << Gr. phylon, a plant. DEPARTMENTS OF BOTANY 9 edge of the structure of plants, just as an account of the different kinds of steam-engines (e. g., locomotives, including freight-engines, passenger-engines, switching-engines, etc.; stationary engines, including horizontal engines, pumping- engines, hoisting-engines, and so on) would be a description of the form and position of the different parts of their ma- chinery. Moreover, not until we know about the different parts of a plant, as of a machine, are we in position to under- stand well what each part is for, and how they all work to- gether. A knowledge of plant structure has thus a twofold importance. Similarly a knowledge of the materials which enter into the various parts of a plant, as of a machine, is necessary if we would understand its capabilities and use- fulness. So one question leads to another, the proper appreciation of one aspect of plants requiring also the study of other aspects. In this way have arisen the different departments of botany, each one representing a special point of view and all being necessary to a comprehensive understanding of the subject. To the various departments have been given special names of which the following are the most important for a beginner to remember :— Economic Botany views plants in their relation to man’s welfare. It is concerned with all the kinds which man uses for food, medicine, clothing, shelter, ornament, or for other purposes; and all which are harmful to him as weeds, poisons, or pests. The ways in which these plants are useful or harm- ful, and to what extent, to what peoples, for how long, and why—such questions as these it seeks to answer as far as possible. Chemical Botany is the study of the properties and quanti- ties of the various substances found in plants. Since the value of a useful plant often depends upon the presence of some special substance, such as sugar, the economic botanist has frequent occasion to learn about the chemistry of the plants with which he deals. Such knowledge is also necessary to an understanding of the life-processes of plants. Systematic Botany is concerned with the accurate descrip- 10 THE STUDY OF PLANTS tion, naming, and classification of plants. It investigates especially the resemblances and differences which .botanists depend upon in their systems of arrangement. Geographical Botany seeks to discover the native home of each plant, its migrations, if any, and the nature of its habitat, 7. e., the surroundings amid which it grows wild. Fossil Botany is the study of the remains of plants of former ages which have been preserved as fossils. Biological! Botany is the study of plants in regard to their ways of life as shown in the form and activities of their parts. Questions which relate simply to the form or structure of parts come within the subdepartment Vegetable Morphol- ogy 2 or Morphological Botany. Such as concern simply the activities of parts, or the life-processes going on within them, belong to Vegetable Physiology * or Physiological Botany. Finally, under Vegetable Ecology 4 or Ecological Botany come all questions as to how the different parts are adapted by their form and behavior to serve the welfare of the indi- vidual and the species, 7. e., the relation of plants to their homes. 1 Bi-o-log’-i-cal << Gr. bios, life; logos, logical account. 2 Mor-phol’o-gy < Gr. morphe, form. 3 Phys-i-ol’o-gy < Gr. physis, nature. 4 E-col’o-gy < Gr. oikos, household. Ecology considers the special ways in which plants solve the prob- lems of their domestic economy, such as their manner of obtaining food, protecting themselves, and providing for their offspring. Ecology, also spelt cecology, is a word recently come into use among botanists, to designate a branch of botany which has been developed almost entirely within the memory of those now living. It has been used in rather various senses but generally with the meaning given above at least implied. Sometimes especial emphasis is put upon the peculiar associa- tions or communities of plants that flourish in different kinds of homes, and upon the physical peculiarities of the homes themselves; but such matters are here referred in large part to geographical botany. CHAPTER II CEREALS 14. What cereals are. The ancient Romans, long before the Christian era, held each year at seed-time and harvest great festivals in honor of their goddess Ceres whom they worshiped as the giver of grain. In these celebrations offer- ings of wheat and barley, called cerealia munera or “gifts of Ceres,” held a most important part. Thus it was that the bread-producing grains came to be known as cerealia or cereals. We now include under this name not only wheat and barley but also rice, oats, rye, maize or Indian corn, and a few other grains of less importance, such as buckwheat. 15. Characteristics of cereals. The general appearance of the most important grain-plants is shown in Figs. 1 to 15. As will be seen, they all agree in having narrow grass-like leaves, and slender upright stems bearing numerous flowers in “ears” or ‘‘heads,” and finally, kernels enclosed by ‘‘ chaff” or “husks.’’ In all but maize each separate kernel is covered completely by two or more of these chaffy envelopes, and even in maize some thin papery chaff may be seen attached to the cob at the base of each kernel. All the cereals are annuals; that is to say, each completes its span of life within a year. All of those mentioned, except buckwheat, are grasses which have been more or less changed from their wild state by ages of cultivation. Let us look more closely at the flowers of the oat. Although appearing rather unlike what we ordinarily call flowers, they have, as will be seen from Figs. 2 and 3, all the parts essential to a true flower. Indeed, because of their simplicity and perfection they afford a convenient standard with which to compare other flowers. In the center of the oat flower, as of flowers in general, is a pistil, in which may be distin- 11 12 CEREALS Fic. 1.—The oat (Arena sativa, Grass) Family, Graminew). Plant in flower, showing sev- eral leafy stalks growing from one root. Three of the stalks bear flower-clusters. About one-fifth natural size. (Bail- lon.) guished (1) a lower swollen part, the ovary, containing a small egg- shaped body, the ove; (2) a pair of elongated middle parts, the styles, each connecting the ovary with (3) a free, terminal part, the stigma, which is here like a little plume. Around the pistil are three sfamens very like what are commonly met with in other flowers. Each stamen consists of (1) a double sac, the anther, in which are produced innum- erable dust-like particles, the pollen, and (2) a threadlike part, the filament, on the upper end of which the anther 1s borne. When the anther is ripe it sheds its pollen, a particle of which com- ing to rest upon an oat stigma brings about the ripening of the ovule into a seed. As the ovule ripens, the ovary enlarges to keep pace with it, forming at last for the seed a firm protective cover- ing which together with the seed constitutes the grain. Mean- while the styles, stigmas, and stamens, having fulfilled their office, wither and fall off. The ripened ovary and its contents together with whatever parts ripen in connection with it (in this case two husks) constitute the fruit. since the purpose of the flower is to form seeds, and this is ac- complished by means of stamens and pistils, these are called the CHARACTERISTICS 13 essential organs of a flower. A flower which has both is said to be perfect; if either alone, imperfect; or if with neither, rudimentary. While the floral parts BE the oat are being formed they are protected by papery husks called bracts, a bract being or- Fic. 2.—Oat. A, Upper part of flower-cluster. B, a single spikelet in flower, with bracts spread somewhat apart. C, one of the outer bracts. D, an inner bract bearing an awn. J, pistil. G, lodicules. A and B about natural size, C, D, and J, enlarged. (Nees.) dinarily a small leaf-like organ belonging to a flower-cluster. A little cluster of grass-flowers together with their bracts, is called a spikelet. At the base of the inner bracts are the so-called lodicules which by swelling spread apart the bracts so as to expose the anthers and stigmas at the proper time for shedding or receiving the pollen. An awn is a bristle- like appendage such as make up the “beard” of many grasses. 14 CEREALS Fria. 3.—Oat. ov MS fs | “4 .S|: £18] 2 o}a].2] 2} s eg 2/8 /elels|s “Ol # |e |e | [2 [3 | LT ry LT : sili ee aT PEER TILE = “= Nh Unb | | i | Bi LL. glalzle lila i eid 4) =) i | il | | Hi Hl root Turnip, *‘Spooy SNoOTIvA Jo (SATIOTeD UI) ONTeA JoNy pue UorTsodur0d yRoIMAYD oy} Burmoys weyO—Osl “oul ayeq pueurg asuv1O wOyaMIAIe AA adv alddy 0}eWI0,.L urydung ‘raquinonyg AdIID aonyeT yovurds SIABIT ‘adeqqro qooys ‘sndpsedsy qing ‘vo9 Jaqn} ‘0}¥30d azTY AA. yy 038}0d JBM Too iro. MEASURES OF ENERGY 115 of proteids, although provided with abundant fats and car- bohydrates will starve quite as truly as if it had no food what- ever, whereas it may live indefinitely (although with danger to health) on a proteid diet! from which all fats and car- bohydrates are excluded. Since proteids alone will support life, we must conclude furthermore that they are also sources of energy, and the question may be asked, What need have we of fats and car- bohydrates? While it is indeed true that proteids may serve as a source of energy, it has been found that the amount of energy derivable from the food we eat is very nearly propor- tionate to the amount of carbon present, and largely inde- pendent of the amount of nitrogen. It is estimated that an average man at moderate work needs daily less than ten grams of nitrogen and about two hundred and eighty grams of carbon; that is to say about twenty-eight times as much of the latter as of the former.” Since in proteids there is only about three and a half times as much carbon as nitrogen, it is clear that in order to obtain from them the necessary amount of carbon, a man would have to consume about eight times as much nitrogen as he had any use for. Not only would this impose an unnecessary burden upon the digestive organs, but so large an excess of nitrogen would be harmful in other ways before it could be eliminated from the system. Hence we must conclude that although proteids are absolutely essential as building material, their inadequacy as sources of energy requires that they be supplemented by carbonaceous and non-nitrogenous food-stuffs. 42. Measures of energy. Aswe have to depend for warmth and strength mainly upon fats and carbohydrates, it becomes important to inquire how these compare with each other in fuel value, for as already shown, these substances are to our bodies essentially as coal to a steam-engine. It was stated in the last chapter that fats af- ford more than twice as much energy as carbohydrates. We must now try to understand more fully what this means and at the same time secure a more exact expression of the relation thus vaguely 1 Tt, is of course assumed that the rations include a sufficient quantity of water and of salts. 2 Physiologists formerly estimated the daily need of nitrogen at twenty grams, but recent experiments indicate that ten grams is amply sufficient. 116 VARIOUS FOOD-PLANTS indicated. When we were considering the amount of any substance in a given food, we were able to express the facts with perfect def- initeness because we were dealing with what could be measured by weight and volume, and because we had the units (gram and cubic centimeter) by which the measurements could be expressed. Al- though neither heat nor mechanical force have weight or volume, they may nevertheless be measured as to their amount by means of suitable units. Such a unit for heat is the amount required to raise the temperature of one kilogram of water one degree of the centigrade thermometer. This amount of heat is termed a Calory.* From very careful experiments it has been calculated that if by means of a steam-engine, one Calory obtained from fuel could be entirely converted into mechanical energy, this would be sufficient to lift a weight of 424 kilograms, 1 meter, or 1 kilogram, 424 meters. The energy required to lift 1 kilogram, | meter, being called a kilo- grammeter, we thus have in the expression / Calory=424 kilogram- meters, what is known as the “mechanical equivalent of heat.” 43. Energy of vegetable foods. [Experiments show that if com- pletely burned, 1 gram of fat yields 9.3 Calories “carbohydrate SALT os co“ proteid SS Ae i These figures also indicate approximately the amount of energy which would be obtained from equal quantities of the same sub- stances consumed in the human body. To estimate, therefore, the amount of energy obtainable from 100 grams of any food of which we know the chemical composition, we have only to multiply the percentage of each nutrient by the number of Calories yielded by a single gram, and add the products thus obtained. This has been done for the vegetable foods of which the composition is given in the chemical chart (Fig. 120); and the number of Calories is indicated by heavy lines having lengths proportionate to the amount of energy yielded by the foods they represent. Foods which yield much energy are commonly described as being ‘‘hearty”’: the lines in the chart may be said therefore to indicate the relative “hearti- ness” or fuel-value of common vegetable foods. But it may be asked, Does a fat and a carbohydrate serve us in exactly the same way? Physiologists tell us that either may replace the other in our food, provided the amounts eaten represent an equivalent number of Calories; but there is this difference that, whereas carbohydrates (which, so far as they are digestible, enter the blood as sugar) are immediately after digestion available as a source of heat and muscular energy, fats require to undergo some preliminary transformation in the body, before they can be used, and are therefore less serviceable for immediate needs. Fat, how- 1 Cal’o-ry < L. calor, heat. RATIONS 117 ever, since it contains so much more energy than glucose in propor- tion to its bulk, is particularly well adapted for storage in our bodies as reserve material; and what is absorbed from our food needs to undergo scarcely any change before being laid away. These differences in usefulness between fats and carbohydrates have been well expressed by comparing the latter to ready cash, and the former to money in a savings bank. This helps us to under- stand the benefit which pedestrians and bicyclists derive from the use of sweet chocolate. The large proportion of sugar (about 50%) yields up its energy immediately in time of need, while the consider- able proteid offers material for the repair of muscular loss, and the abundant oil remains as a more slowly available reserve. Likewise, the special craving which young people have for sweets, receives at once its explanation and justification when we remember the extraordinary activity which belongs properly to their period of life. It needs to be pointed out, however, that the quantity of carbohydrate eaten should be strictly proportioned to the amount of bodily activity; for otherwise there will be left in the system an excess of sugar, which may either go to produce an unhealthy accumulation of fat, or by undergoing acid decomposition, seriously disorder the digestive organs. Too much sweet food and too little exercise is one of the commonest causes of indigestion and obesity. 44. Rations. Recent experiments indicate that the needs of an average man would be fully met by a daily ration of 300 grams of carbohydrate, 50 grams of fat, and 50 grams of proteid.? This gives of nitrogenous material sufficient to cover an average daily loss of about 8 grams of nitrogen, and of carbonaceous fuel 1 More or less variation from the above figures would of course be required to meet the needs of different ages, sexes, constitutions, and occupations. A discussion of such details cannot well be undertaken in this place. It should be said, however, that physiologists of the highest standing now admit that former estimates of the body’s needs based upon records of the amount commonly consumed are too high for maximum efficiency. ‘The standard which has been most generally adopted by American writers on nutrition calls for 125 grams of proteid, with sufficient fat and carbohydrate to yield a total of 3,500 Calories as the daily ration for a man at moderate muscular work. These figures were derived mainly from observation of what many healthy Americans actually eat, and are admittedly but rough approximations erring rather on the side of excess than deficiency. Good health is undoubtedly maintained on such an allowance, but this, of course, is no proof that eating somewhat less would not conduce to even better health and greater vigor. A very liberal allowance would be 400 grams of carbohydrate, and 100 grams each of fat and proteid for an average man. 118 VARIOUS FOOD-PLANTS enough to yield about 1,900 Calories or 805,600 kilogrammeters of energy, which has been found to be approximately the amount ex- pended in 24 hours. If at first sight this seems to be an exaggerated estimate of the energy given out, it should be borne in mind that a very large share goes to keep up the warmth of the body; while of the remainder which is transformed into mechanical activity, a considerable proportion is used up in the muscular movements of the digestive organs, in breathing some 23,000 times, and in mak- ing more than 600,000 heart-beats, thus leaving only about one third of the whole available for locomotion and external work. The main point which here concerns us regarding the make-up of a proper daily ration is the relative proportion of nutrients rather than their absolute amount. On the basis of the figures given, it may be stated roughly and in a general way that 1 part proteid, 1 part fat, and 6 parts carbohydrate, would ordinarily mect the daily needs of an average person, or in other words that one’s food should be about § proteid, 3 fat and ~ carbohydrate. In the rations recommended it is assumed that the foods chosen are easily digestible; for it is not what we eat but what we digest that nourishes us. For students and other brain-workers digestibility 1s of es- pecial importance since their largely sedentary life leaves them but little surplus energy to spare for unnecessary digestive work. A glance at the chemical chart (Fig. 120) will show that many vegetable foods do not have their nutritive constit- uents in anything like the standard proportion. This means that if a man were to obtain all his nourishment from such foods, he would have to eat too much of one ingredient (generally a carbohydrate) in order to get enough of another. When it is remembered that the dry substance of meats, fish, eggs, and other such foods of animal origin, consists almost entirely of proteids and fats, we see that here also there is a similar disproportion, although in another direction. Since, however, the constituents which are deficient on the one side, are in excess on the other, a mixed diet combining animal with vegetable foods, is most likely to be well-balanced. From this point of view it is interesting to notice how generally the instincts of mankind have led them to prefer combinations of food wherein the components supplement RATIONS 119 each other, and thus approximate to the chemical ideal. The appropriateness of combining bread and butter we have already had occasion to notice. Similarly in “crackers and cheese,” ‘mush and milk,” ‘eggs on toast,’ “meat and potatoes,” and many other favorite combinations which will readily occur to the reader, we have the animal part poor in carbohydrate and rich in fat and proteid, supplemented by a vegetable food comparatively poor in these latter ingredi- ents, but rich in sugar or starch. Sometimes, indeed, as in “pork and beans” we may have a highly valued combination in which not only the carbohydrate but also nearly all the proteid is furnished by the vegetable part, the animal por- tion being little else than fat; or, as in certain salads, we may have the fat represented almost entirely by olive-oil. Those who prefer for any reason to abstain entirely from meat or other animal food may find adequate substitutes in various seed foods of highly nitrogenous composition, as the table clearly shows, provided the greater difficulty of digesting them does not offset their advantages, as is often the case with persons of sedentary habit. The recent military triumphs of the Japanese show in a striking way what hard physical work can be done on a diet consisting in very large part of rice. In most cases, however, it will be found that the vegetable foods are of value to us chiefly as contributing carbohydrates, and thereby supplying the most marked deficiency of foods derived from animals. We have now an answer to our question regarding the special nutritive value of vegetable as opposed to animal foods. Both, as we know, yield us building material and fuel; and either the one or the other sort of food is used almost or quite exclusively by certain races of mankind, just as by herbivorous or carnivorous animals; and, furthermore, we have scen that whatever nourishes the animal kingdom, including ourselves, must be derived ultimately from plants. Nevertheless, the teachings of chemistry and the practice of the best-fed and most vigorous peoples agree in showing that while it may be desirable for us to depend mainly upon animal food for our nitrogenous materials and carbonaceous reserve, it is to vegetable foods that we must look to supply (8) JUSPUY | * (4) SMO ISLYoIg sodomngy ’ PUSTOUY| Oe PRS PEs 21S V ayeroduto} * \ Sodoanny | * eS LaO Sumpeag eeu sins eek (4) Bsy A g tom ULopO] “BoLloULy U}LON SOMO Ig, Ps Pe ee ee “7 wonoury YO, Jo Opa | : DILO}SUPor eee “woNOULy ip L}UID) (j) JUowWUy odoiny uBR é Uy aS I Dv }USLDUY (a) vIsy ayeroduroe} “A ‘odor | (4) do stot d) BMOGIS “AA fodomay JUSTOUY “co RIsy oyesoduta y, juUODOUy “tISV ANS {USE WOU. 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WU-URII, (pqyp phan.) Wu-S1OYxO TY (palais suUD]ON ff) Wud} NE ‘(pian supjbn f) WUTE AA. (Dun]aap snpfiwo)) WoqTy (DAIS DIUDISD,)) USI) (unjuanasa unaidoboy) yeoy AM youd. (shopy D9Z) UO) WEIPUT 10 ozIe]Y *(a]DaLIad IDII) ONY Shy ae re wa (DaDs DUIAP) SYBO Ca a aha Shae a Re (payDS D2hIQ) IY ee ae (unaryDS wnapLo FL) Lore “(UNAYDS WNIYLLT,) YEOTLAL oure NT AWOP[ GAILVN FHL dO AGIA UVINEVY, ULopop poywayypnouy |” }UOLOUY (4) Wopoyy oO ISI jyuODUy OO JSTYO.I ULOpoyy JULUY dO SOI dO dMO}STYPIg }WLUY jUOLDUy dU ISI ({) JuePUy Ulopoy quodayY oMO}sttpoig yuU9D0Y UIOPOTY VUOIOUY juODUy oWO}SMpoig oO }STYaIg dO sor g oloysTyaIg oo ySsttparg jUsPOUy JWI jUsLDUY qualuy DIO YSTYoI J juoLUy juanuay WOOL 9} VAIAUT} T}L0 N woop pus odoin, JO ysvoo oNURTLVY “N cctal avons Mah Samet detNar dm yeee the difference is not always well marked. Soft pine (mainly white pine) is the principal wood used in common carpentry, and enormous quantities are consumed also in white cooper- age, cabinet work, toy-making, pattern-making, and ship- building; and for crates, boxes, ete. Hard pine is most ex- tensively used in heavy construction, especially for bridges and similar exposed work; and is unequaled for spars, masts, planks, ship-timbers, and heavy beams. It has especial advantages for flooring and exposed stairways on account of its durability. Larch (Fig. 259) is very like hard pine in appearance, qualities, and uses. For ship’s “knees” (7. e., angular braces giving stiffness to the frame) the lower part of the tree as it curves naturally when growing in swamps has great advan- tages. Owing to its durability the trunk is valued also for telegraph-poles and railway-ties. Spruce (ig. 260) resembles soft pine in appearance and qualities and is commonly put to the same uses. Being re- markably resonant it is preferred to all other woods for the sounding-boards of pianos, and the bodies of violins, guitars, and similar stringed instruments. Red cedar (Fig. 261) has just the lightness, softness, and even texture required for lead-pencils; and is used in very large quantities for that purpose, almost to the exclusion of other woods. It also finds a place in cabinet work and for cooperage; likewise for fence posts on account of its unusual durability in contact with soil. Redwood (Hig. 262) closely resembles red cedar in appear- ance and qualities and has many of the samc uses. Its great durability makes it highly valued for shingles, and its large TRUE WOODS 971 dimensions and rich color give it especial advantages for certain purposes in cabinet work and interior finish. Hemlock (Fig. 263) is soft and stiff though brittle, com- monly cross-grained, coarse, and splintery. It is of value chiefly for rough carpentry, and railway-ties. Fic. 259.—European Larch (Larix decidua, Pine Family, Pinacew). 1, twig with long and short branches, and with a cone continuing as a branch at a. 2, twig with staminate and pistillate flowers. 3, staminate flower, 7. 4-6, stamens. 7, 8, 9, scales from young cone. 10, ripe cone. 11-13, seed-bearing scales. 14, seeds, with and without wing. 15, short branch or ‘‘spur,’”’ cut vertically. 16, leaf, entire, and cut across. (Willkomm.)—Tree growing 30 m. tall; bark dark grayish- brown; leaves bright green; staminate flowers yellow; pistillate flowers purplish; fruit brownish. Native home, Europe. 272 INDUSTRIAL PLANTS 74. Pseudo-woods, as we have seen, may be defined as more or less wood-like materials which, however, show no trace of pith rays or annual rings. Under the name poreupine-wood the outer harder part of 10 Fig. 260.—Norway Spruce (Picea cxeclsa, Pine Family, Pinacee). 1, twig bearing staminate flowers. 2, twig bearing a pistillate flower. 3, ripe cone. 4-6, cone scales, bearing seeds. 7, seeds, with and without wing. &, stamen, two views. 9, leaf, entire and eut across. 10, seed- ling, with seed-shell still attached. 11, same, older. 12, a ‘‘ pineapple gall”? produeed by the spruce aphis (Chermes abielis). (Willkkomim )— Tree growing 45 m. tall; bark reddish brown; leaves dark green, glossy; flowers purple; fruit brown. Native home, Europe. Much planted. INDUSTRIAL PLANTS 27: Fic. Fic. Fira. 263.—Hemlock (Tsuga canadensis, 261.—Red Cedar (Juniperus virginiana, Pine Family, Pinacee). Fruiting branch, 3. Leafy tip. (Britton and Brown.)—Tree growing 30 m. tall; bark brownish, shreddy; leaves dull green; flowers yellowish; fruit light blue. Native home, North America. 262.—Redwood (Sequoia sempervirens, Pine Family, Pinaceew). Fruit- ing branch. (Nicholson.)—Tree growing over 100 m. tall; bark reddish brown; leaves mostly scale-like; flowers inconspicuous; fruit brownish. Native home, California. Pine Family, Pinacee). Leafy branch, 3. Staminate flower. Cone. Cone-scale. (Britton and Brown.)—Tree growing over 30 m. tall; bark flaky; leaves dark green above; flowers yellowish; fruit brownish. Native home, Eastern North America. 274 INDUSTRIAL PLANTS the coconut trunk (ig. 34) is imported for the use of cabinet makers in ornamental work and to some extent for canes. Canes of rather curious appearance are made sometimes also from the mid-rib of the gigantic leaves of the date-palm kia. 264.—Tree-cabbage (Brassica oleracea var. acephala, Mustard Family, Crucifera). Plant, v2. = (Vilmorin.)—Perennial herb growing 2 m. tall; leaves, etc., as in other forms of cabbage. Native home, Westera Europe. (Fig. 108). Another curious walking-stick is made from the stalk of an extraordinarily tall variety of cabbage (Wig. 264). The bamboo (Pig. 224) of which there are many species, has, as is well known, a very wide range of uses among which the most familiar to us are for canes and umbrella handles, fishing- INDUSTRIAL PLANTS 275 Fic. 265.—Bottle-gourd (Lagenaria vulgaris, Gourd Family, Cucurbitacee). Plant in fruit, 2:. Flower. (Vilmorin.)—Annual, climbing by tendrils to a length of 10 m. or more; hairy throughout; flowers white; fruit yellowish cr orange, very various in form, sometimes 2 m. long. Native home, Old World Tropics. microcarpa, Palm Family, Ivory (Phytelephas L nil; Palmacee). Plants, in flower, a staminate plant in front, and a pistil- (Karsten.)—Shrub with short stem sending up leaves Fic. 266, I.—Vegetable late one behind. 7-8 m. long; fruit dry. Native home, Tropical America. 276 INDUSTRIAL PLANTS rods, articles of furniture, and various ornaments. In tropical and eastern countries where bamboos flourish, the uses to which the light, strong stems are put would require pages to enumerate. The hard parts of certain fruits may be considered also as pseudo-woods, and are sometimes put to minor uses of importance. The hard inner shell of the coconut forms the sunt eS Via. 266, 11.—Vegetable Ivory. A, pistillate flower-cluster in bud. B, staminate flower. C, stamen. D, pollen. £, pistillate flower, cut vertically, showing pistil accompanied by rudimentary stamens. F, fruit, cut across. G, seed. (arsten.) bowl of the familiar coconut dipper. The shells of various gourds (Fig. 265) play a most useful part as vessels for holding liquid or storing food, in the domestic economy of many regions. Finally, may be mentioned the vegetable ivory (Wig. 266) which is a seed-food that takes the form of nearly pure cellulose. Large quantities of these seeds are imported and used ino place of ivery or bone for umbrella handles, PSEUDO-WOODS 277 knobs, buttons, balls, and various other small articles of turnery. For the most part, pscudo-woods, although sometimes Fia. 267.—Cork Oak (Quercus Suber, Beech Family, Fagaceew). A, fruiting branch. 8B, twig with staminate flower-clusters. C, staminate flower. D, pistillate flower. (Redrawn after Schneider.)—Tree growing 15 m. tall; bark thick and spongy; leaves whitish, hairy beneath; flowers yellowish; fruit brownish. Native home, Southern Europe, and Northern Africa. locally important, are of comparatively small use and need not here be further discussed. INDUSTRIAL PLANTS tw ~I we Fie. 268.—Cork Oak. Wedge of trunk cut across to show wood, with strong pith-rays and annual rings, and the thick bark consisting of the outer “‘virgin cork" (light colored) and the inner ‘cork mother” (dark colored). (Figuier.) Pia. 269.—Harvesting Cork. (liguier.) CORK 279 75. Cork is the light, waterproof, compressible yet elas- tic material forming the outer bark of the cork oak (Figs. 267- 269). Like true wood it is built up of annual layers formed by a cambium. It differs from wood in having the inner layers the younger, in being non-fibrous, and in containing about 70-80% of a mixture of waxy and tallow-like sub- stances which is known as suberin. Very many plants pro- duce cork in their outer parts, but only the cork oaks form masses sufficiently large to be of economic use. The imperviousness to water, the elasticity, and the firm- ness of cork, upon which its economic value mainly depends, render it in the first place useful to the tree as a protection for the tender inner bark where processes of vital importance are carried on. Since these processes cannot proceed without free access of air the thick cork layer is found to be pierced by numerous breathing channels extending radially to the surface. Besides these channels rifts naturally occur in the outer bark as it is stretched by the increasing bulk of the wood within, and by the new layers of bark. In the young tree the first few layers of cork are compara- tively thick while those formed later are only about 1-2 mm. in thickness and soon become so brittle and so badly cracked as to be unfit for finer uses. Such inferior cork, suitable only for fuel, packing, fish-net floats, rustic work in conserva- tories, and the like, is all the tree ever produces if left undis- turbed. But in cultivation when the trees are from fifteen to twenty years old all of this “virgin cork,” as it 1s called, is cut away, great care being taken not to injure the tender part within known as the ‘‘cork mother” because it includes the cambium. The effect of this operation upon the tree is in every way beneficial. Henceforth the cork produced is more abundant, softer, and more homogeneous; the breathing channels are farther apart; and the cracks become far less troublesome. For a century and a half or even longer, at intervals of eight to fifteen years, slabs of fine cork 5-20 cm. thick are peeled from the trunk in the manner illustrated (Fig. 269). The harvesting takes place in summer when the inner bark adheres most firmly to the wood. After being stripped from the tree the slabs of cork are scraped so as to 280 INDUSTRIAL PLANTS clean the outer surface, are then flattened under pressure with the aid of heat, and finally tied in bundles for shipment. By far the most important use of cork is for stoppers. It is estimated that the daily consumption amounts to twenty million. Cork stoppers are cut either by hand or by ma- chinery. Large flat corks have to be cut so that the channels pass from top to bottom. Such corks require, therefore, the use of some sealing material such as wax, to make them impervious. Smaller corks are cut so that the channels go from side to side and hence are air-tight without sealing. In the cutting, about half the material, or more, becomes waste chips. So valuable are the properties of cork, how- ever, that even in this form it may be utilized in important ways. Thus, pulverized and mixed with rubber or with boiled linseed-oil it forms when spread on canvas a floor cover- ing at once durable and sound-deadening. Coarsely ground cork serves well on account of its softness and clasticity as packing for fruit, especially grapes; and, when glued to paper forms a safe wrapping for bottles in transportation. The same remarkable properties make masses of cork most effective buffers for vessels. In the form of thin sheets it has long been used as a material for insoles and hat linings. The lightness of cork has especially recommended it for artificial limbs, handles, net floats, and life-preservers; while the uni- form texture and the ease with which it may be shaped have made it valuable to model makers and even to turners and carvers. Although cork was known to the ancient Greeks and Romans, and there is record of its use by them for the soles of shoes and as stoppers for wine vessels, tt has been generally used only within the last few hundred vears. 76. Elastic gums, including india-rubber or caoutchouc ' and gutta-percha,’ are tough, more or less clastic and water- proof solids which separate as a curd from the milky juice of a number of tropical plants. Smal quantities of caoutchoue are present also in many ol our native plants having a milky juice, but the amount is ' Pronounced koo’chuk. “Ch pronounced as in church, ELASTIC GUMS 281 much too small to be of any economic significance. The use of this Juice to the plant is not altogether clear; but from the fact that it flows readily from a cut and after a little while hardens upon exposure to the air, the conclusion seems war- ranted that it serves in part at least as a ready means of Fig. 270.—Brazilian Rubber-tree (Hevea guyanensis, Spurge Family, Euphorbiacer). H;,NO,;) which is extracted by water from the leafy shoots, and, under the influence of an enzym which accompanies it, gives rise to a compound re- sembling glucose and to indigo blue (CyHyNsO:). A sub- stance which thus decomposes into a sugar and some other compound is known as a glucoside. Indigo blue is insoluble in water and can therefore be separated along with certain impurities by filtration. The pasty mass retained is dried in cakes to form the indigo of commerce. The imsolubility of indigo blue in water presents a peculiar difficulty to its use as a dye, yet at the same time gives it a great advantage when once it is incorporated with a fiber. The difficulty is overcome by taking advantage of the fact that indigo blue may be readily changed (in various ways which increase the proportion of hydrogen) into a colorless substance called indigo white (CyHy2N2O02) which is soluble in dilute alkaline solutions and has the fortunate property of quickly changing back to indigo-blue on exposure to the air. The means com- monly employed by dyers to change the indigo-blue is to add indigo to vats containing lime-water in which bran or mo- lasses or some other substance is undergoing fermentation. When the indigo is all transformed and dissolved, a piece of white woolen or cotton soaked in the solution and then exposed to the air soon takes on a permanent blue color. A considerable number of plants have been found to con- tain indican, and several different species are cultivated in India and other warm countries for the manufacture of indigo. Of these plants the most important one is the dyer’s indigo shrub (Fig. 275) Logwood is iene from a small Central American tree (Fig. 276). It is exported in the form of logs from whieh the sap-wood has been removed. The coloring matter which it yields, is, like indigo, not present in the living plant but is derived from a colorless glucoside called hematoxylin (C\,Hy,0,) which in turn readily oxidizes to form the deep violet-purple compound known as hwmaledn (Cy H 204). It is interesting to observe that this transformation involves the loss of two atoms of hydrogen just as does the ehange of the white indigo into the blue. Unlike indigo, however, COLORING MATTERS 293 . 275.—Dyer's Indigo Shrub (Indigofera tinctoria, Pulse Family, Le- guminose). Flowering branch; a, flower, enlarged; 6, standard (upper- most petal), back view; c, wing (side petal), inner view; d, e, keel-petal, inner and outer views; f, flower with corolla removed; g, pistil. h, fruit, natural size; 7, seed; k, same, cut vertically. (Berg and Schmidt.)— Shrub growing 2 m. tall; leaves downy beneath; flowers reddish yellow; fruit dry. Native home, Southern Asia. 294 INDUSTRIAL PLANTS logwood of itself does not make a permanent dye. It requires the use of a mordant, that is to say, some substance such as a salt of iron which fixes the dye upon the fabric. Thus used it makes one of the best blacks for wool or cotton. In com- bination with iron, etc., it is used also widely in the manu- facture of writing inks. Lampblack is the finely divided carbon deposited from the smoke of rosin or oil burned with slight access of air in eV Fic. 276.—Logwood-tree (Hamatorylon campecheanum, Pulse Family, Leguminose). A, flowering branch. 8B, flower. C, same, cut verti- cally. D, pod. (Taubert.)—Tree about S m. tall; leaves smooth; flowers yellow, fragrant; fruit dry. Native home, Tropical America. a special chamber. It is used extensively in the making of printing-ink, and forms the basis of india-ink and of various black pigments used in painting, leather-finishing, and the like. Lampblack is one of the most important of coloring matters. Tan-bark is obtained from many trees, including hem- lock (Fig. 263), oak (Fig. 243), willow (Fig. 228), chestnut (Fig. 24), larch (Hig. 259), and spruce (Fig. 260), which are rich in tannins. These substances, as already explained in sections 57 and 60, are astringents which are present in OILS 295 various parts of many plants, and agree in forming an ink- like product when combined with an iron salt. Though chemically more or less diverse they mostly resemble indican and hematoxylin in being glucosides, and are believed to be usually waste products of the plant producing them. A property of tannins which renders them especially valuable to the dyer is that they are readily absorbed in solution by cotton, linen, and silk, and will then precipitate various dyes within the fiber, thus serving as a mordant. But the chief property which gives industrial importance to plants rich in tannins is the power which these substances have of so combining with animal skins as to render them permanently pliable and resistent of decay. Hence it is that a hide soaked, under proper conditions, in an extract of tan-bark becomes leather. At the same time, the staining powers of the tannin and associated substances may be taken advantage of to impart a strong color to the product. 79. Oils, whether fixed or volatile, are very generally pres- ent throughout the vegetable kingdom; and, as we have already seen, they are often of much economic importance as food or flavoring, and in medicine. They are of scarcely less value in the industrial arts, immense quantities of dif- ferent vegetable oils being consumed in the manufacture of paints, printing-ink, varnishes, soaps, and perfumery, and as lubricants and illuminants. As vehicles for pigments fixed oils are selected which not only will hold the particles of coloring matter in perfect sus- pension, and so make it easy to spread them evenly over a surface, but which also will harden promptly when thus spread into a film exposed to the air. Oils which harden in this way are called drying oils although the change which takes place depends not upon the evaporation of a volatile solvent, as in the drying of certain varnishes, but upon the absorption of oxygen which changes the oil into a varnish-like substance. Linseed-oil, which is obtained by pressure from the séeds of flax (Fig. 217), is the one most widely used by painters. Its “drying” qualities are much improved by boiling. For use in printing-ink the oil is boiled until it is very thick. Other drying oils which are somewhat superior to linseed-oil are 296 INDUSTRIAL PLANTS poppy-oil, from the seeds of the opium poppy (Fig. 172), and nut-oil, from the kernels of the English walnut (Fig. 27). These being comparatively expensive are reserved for fine painting. Linseed-oil is invaluable also as a solvent for copal and other resins, with which it unites at a high temperature to form the highest class of varnishes. Entirely by itself it is used extensively to give an attractive ‘oil finish”? to wood- work. In certain varnishes the volatile oil or spirits of tur- pentine, known commonly to the trade as ‘“‘turps,” is the solvent used, and is likewise indispensable to painters as a means of thinning their colors. Any of the fixed oils combined with an alkali makes soap. When potash (or lye from wood ashes) is used soft soap is formed; hard soap being made with soda. Chemically the fixed oils are mixtures, in various proportions, of compounds called glycerides. A glyceride is so called because it consists of glycerin (the familiar sweetish substance soluble in water) combined with an acid. Linoleic, oleic, and palmatiec acids are among the most important in vegetable oils. The gly- ceride of linoleic acid, called linolein, forms 80°; of linseed- oil, and gives to this and to other drying oils their peculiar power of hardening by oxidation. Olein, the glyceride of oleic acid, is the main constituent of olive-oil. It is liquid at ordinary temperatures and becomes rancid by oxidation. Palmatic acid forms a glyceride, palmatin, which is not liquid at ordinary temperatures. It is the main solid constituent of coconut and other palm-oils. When any fixed oil is mixed with an alkali, the glycerides present are decomposed each into its peculiar acid and glycerin, and the acids unite with the alkali to form soap, leaving the glycerin free. Inferior grades of linseed ofl and other cheap oils are used for soft-soap. Oil from the olive (Fig. 113) is used extensively for castile, and other fine toilet soaps. Other hard soaps of various grades are made from “ cocoa-buller ”? (see section 39), and oils from coconué (Fig. 386), collon-seed (Pig. 215), peanut (Pig. 32), and almond (Hig. 31). To give an agreeable odor to soap a large variety of volatile oils are introduced during the process of preparing the product FUEL 297 for market. The oils of wintergreen (Fig. 147), marjoram (Fig. 137), coriander (Fig. 143), thyme (Fig. 134), caraway (Fig. 140), and many others are thus used to a greater or less extent. These same volatile oils enter also into the manufacture of perfumery; and for this purpose many other volatile oils are more or less in demand, as, for example, the oils of nutmeg (Fig. 129), allspice (Pig. 123), sassafras (Fig. 160), peppermint (Fig. 146), spearmint (Fig. 135), orange-peel and orange- jlowers (Fig. 106), and the oil distilled from the wood of red cedar (Fig. 261). It is to the fragrant oil obtained from the bark of white birch (Wig. 254) that the characteristic odor of Russia leather is due. None but fixed oils can serve as lubricants; and of these, only the non-drying ones are suitable. The vegetable lubri- cants most extensively employed are (1) olive-otl, used for this purpose mostly in southern European countries where a sufficiently good quality may be obtained at a low price, (2) rape-oil from the seed of a variety of turnip grown widely in northern Europe and India, and (3) cotton-seed oil used largely in this country. As uluminants vegetable oils have not to-day the impor- tance they had before the introduction of petroleum lamp-oil and paraffin candles. Nevertheless, large quantities of vegetable illuminants are still consumed, especially in regions where mineral or animal oils are comparatively expensive. Almost all the fixed oils in common use for other purposes have served for burning, but the non-drying oils are pref- erable. Olive, peanut, and rape oils, which are all rich in olein, are among the best. Palmatin, as we have seen, is an important constituent of coconut-oil. This substance sepa- rated from the more fluid parts of the coconut-oil and other palm-oils affords an excellent material for candles. 80. Fuel, whether as a source of heat or of power, being indispensable to the carrying on of almost every industry, and being also a necessity for steam-transportation, for the heating of buildings, and for cooking, it is plain that civiliza- tion could not have developed as it has, nor could it possibly go on, without this source of heat. 298 INDUSTRIAL PLANTS Anything which burns readily in the air will serve as fuel; and, indeed, various sorts of refuse are thus utilized: for ex- ample, wheat straw is made to run steam threshing-machines, and the crushed stalks of sugar-cane are used in the boiling of the juice. But, in general, wood, peat, and coal, and their products, charcoal, coke, and illuminating gas, are the fuels most extensively used. Wood is the most used of all fuels. All woods when per- fectly dry consist of nearly 99% of combustible material and about 1% of inorganic matter which remains as ash when the wood is burned. Air-dry wood contains about 25% of water, and in green wood it may be as much as 50%. This water reduces the fuel value not only as taking the place of combustible substances but also as using up the heat necessary for its evaporation. Hence the economy of well- seasoned fire-wood. The value of different fuels may be conveniently compared when stated in terms of the amount of water which a unit weight will evaporate. Thus, green wood is found to yield enough heat to convert about twice its weight of water at 100 C. into steam; air-dry wood about three and a half times; and perfectly dry wood over four times its own weight. So far as chemical composition is concerned soft woods should yield on burning about the same amount of heat as hard woods of equal dryness. In practice, how- ever, considerable differences are found, depending in part upon the ease with which complete combustion may take place, as shown by the amount of smoke, and in part upon compactness of structure, and so forth. Wood as being a flaming fuel is especially well adapted for heating surfaces of large extent, as in the boilers of steam-engines. The small amount and the soft crumbly nature of its ash give wood a further advantage over peat and coal. Peat consists of the more or less carbonized and compacted deposits of vegetable substances which accumulate in bogs and marshes, and, in the presence of water, slowly decompose. Peat-bogs form chiefly in northern countries. Near the sur- face they consist largely of moss like that shown in Fig. 227 with which, however, a number of other plants are found growing. In the deeper layers that have been buried for a 299 FUEL Cglmojog) —*yUOIF oY} TOM YUE WYBI 9y} uO [rey (wnyofrauns wnpphydousaydy) syuvid ,, yvo[-oFpom ,, + (sazvplo,)) SULIOdSOULIAT PoAvo] aBIeT “¢ — *(st1ajdorwvzYy) SuAI} Surquarpo ore asoy} I + (WOLpUrpo)/)) SIBIS o51L] Y}IA 9uo [BOLIpuTAD & puT ‘(woL“puspobursig) Yunsy oer}s01d [BPloUod B *(y2LD7IDIS') JOOLD OMY ,‘SOSSOUL -qnp,, 19YIO “F ‘(volpuspopidaT) ,,ssow-qnyo,, UTI WE *(snsown. PLULDID,)) ¢, YSN SuLNoos ,, JURIT VG ‘(uojhydoba yy) YUNAY ULoy 9yeAjso1d wv sty} MOTAq ! ( dajdouayd gy) Udo} Surquirypo wv ‘ (IL oY} O} /SJOOI-90vIG YIM (stla7d 0097) U1oj-901} B‘T *03v sIvak YNO‘OOO'OF JNoqu ‘ATYSnor ATA ‘aq 0} poy { ,, pOMog snorojruoqae,) oq} JO o[pprta oy} SuLmnp duress v Ul SUIMOIG poreadde sary 0} posoddns o. q e n n ~~ 7 Ay 1 tw a 300 INDUSTRIAL PLANTS long period of time, the material is so transformed as to be like a soft, brown coal. In regions where wood is scarce peat is highly valued as a fuel. It is commonly more bulky than wood, and has from 5 to 15 times as much ash. Its heating power is about the same. Coal, like peat, consists of the decomposed and compacted remains of plants. It differs from peat principally in being harder and more completely reduced to carbon. But peat passes into coal by insensible gradations so that none but an arbitrary line can separate them. The coal with which we are most familiar may be regarded as a peat-like material of very great antiquity,—so ancient that the plants from which it was formed have been extinct for many ages. Some idea of the appearance of certain of these coal plants may be gained from Figs. 277,278. In comparison with wood and peat as a fuel, coal has the advantage of possessing greater com- pactness and more power of heating. It will convert into steam about 7 to 9 times its own weight of water. The most objectionable features of coal are its large amount of troublesome ash, which often interferes with good combus- tion, and its offensive smoke, which is excessive from soft coal. Charcoal burns without flame or smoke, and has over twice the heating power of wood, or as much as the average coal. It is produced mostly by smothered combustion of billets of wood, commonly arranged in conical piles, and cov- ered with earth. When wood is subjeeted to dry distillation creosote, wood-alcohol, and other volatile compounds pass into the condenser, leaving charcoal in the retort. The charcoal produced at the highest temperature yields most heat when burned, and is therefore of most use in metallurgy ; that produced at as low a temperature as possible is the most inflammable and thus the most suitable for mixing with niter and sulphur to make gunpowder. Coke bears somewhat the same relation to coal that char- coal does to wood. Tt is similarly obtained by smothered combustion in covered piles, or by heating in special ovens or retorts. Like charcoal it is nearly pure carbon, and is used extensively in metallurgy and for other purposes where a FUEL 301 smokeless fuel is required. It was originally a by-product in the manufacture of illuminating gas. Now it is manu- factured expressly for metallurgical purposes, the ovens being so constructed that the inflammable gases driven off are made to serve largely as a source of heat in the process. Fic. 278.—Fossil remains of a giant club-moss (Lepidedendron sp., Scale- tree Family, Lepidodendracew). From the coal period. (Baillon.) Illuminating-gas is made by subjecting coal or wood to a high temperature in a retort, and collecting and purifying the gas given off. For obvious reasons coal-gas has proved to be a most convenient fuel especially adapted for household use in large cities. The study of fuels leads one to think not only of the forests 302 INDUSTRIAL PLANTS of to-day and of bog-plants that lived perhaps hundreds of years ago, but in imagination one is led back to strange forests which disappeared from the earth many thousands of years ago and became turned to stone. Therefore, if we ask ourselves, Whence comes this material that men burn to get heat, and power? the answer is, From the bodies of plants, some of which lived ages before the coming of mankind. And if we further ask, Whence comes the energy which all these plants have stored in their bodies, and left for us to set free? students of nature tell us, From the sun. That is to say, plants with foliage are the sunbeam-traps of our planet, and except for their marvelous ability to lock the energy of sunshine into the material of food and fuel, the life of the world as we know it would be impossible. How plants are able thus to store up sunshine, and why they do it, are questions to be answered only by the study of their processes of life. 81. Useful and harmful plants in general. From our study of some of the more important groups of economic plants we have learned not only that the very existence of the human race depends upon the vegetable kingdom but also that the progress of humanity at every stage has been profoundly influenced by the properties of plants and by man’s knowledge of them. The needs of primitive man must have been met largely by wild plants. Through the cultiva- tion of plants, as we have seen, civilizations were developed in those regions where the most useful plants grew most abundantly. The desire for spices and similar luxuries led to the discovery of America. The vegetable products of the New World are now revolutionizing human life to the re- motest ends of the earth. Our brief study of vegetable foods, food-adjuncts, medi- cines, and raw products has shown that what we take from plants for our own use has often a similar use for the plants themselves, though sometimes the use is quite different; and in some cases, so far as we can see, the product is of no use whatever in the plant’s economy. In other cases it has been found that substances poisonous to us are also poisonous to the plants which produce them, just as the venom of cer- USEFUL AND HARMFUL PLANTS 303 tain animals may be fatal to themselves. Since, however, some of these plant poisons are among the most valuable of medicines, it is plain that no dividing line exists between harmful and useful plants. Judged in its relation to our welfare the same plant may be either useful or harmful according to what we do with it. Obviously, the more we know about their properties the less likely are we to suffer harm from plants, and the more likely are we to benefit by them. The student should understand clearly that in this book the aim is only to introduce beginners to the study of plants. Our purpose is merely to lay a good foundation for future studies which shall further advance general culture. There has been no intention of giving here a complete outline of economic botany. Accordingly, a great many plants of high economic importance have not been mentioned; and some of the chief uses of plants, and some of the most serious ways of their working harm, have been passed over with bare mention, or have been ignored. Thus, in regard to the food of domestic animals but little has been said of the fod- der raised for them, and nothing at all of pasture plants upon which some of the principal industries of the world depend. The many plants which afford bees the material for making honey and wax, and those which serve as food for silkworms or other insects of economic value have also been neglected. So also have we omitted reference to the plants which do great service in binding shifting sands that but for these sand-binders would devastate extensive areas: to those plants similarly used to prevent the washing away of soils; to trees set out as wind-breaks for protecting tender vegetation, as drainers of swamp land, or for shade and beauty; and to the innumerable flowers and foliage plants cultivated or collected for ornament. Likewise, among harmful plants neither weeds nor destructive parasites have been included. Not only has our study neglected these groups of plants which especially affect the welfare of mankind but it has been forced to leave out of account some most extensive in- fluences which vitally concern animals in general. For ex- 304 USEFUL AND HARMFUL PLANTS ample, there is the influence of forests upon water-supply, by which is meant their action as reservoirs feeding the streams gradually in spring, thereby avoiding floods, and at the same time keeping back plenty for the dry season. Then, too, there is the important action of plants in soil- making, and the purifying influence of vegetation upon air and water whereby they are made to serve better the needs of animal life. All these various relations of plants to the life of the world, and to our owne lives in particular, are as profitable and attractive matters of study as any that have claimed our attention; and the student will do well to learn all he can regarding them. It should be said, however, that many of these relations are best understood in the light of vegetable biology. Moreover, the student’s pursuit of economic botany cannot well proceed much farther than we have here at- tempted to go, without his first acquiring such an elementary knowledge of systematic botany as the following chapters may help him to gain. CHAPTER VII CLASSIFICATION AND DESCRIPTION 82. Systematic classification. In Chapter I it was pointed out that the large number of plants which botanists have to study has made necessary some sort of classification or orderly arrangement into groups within groups. Plainly, one of the chief requirements of such an arrangement is that it shall bring nearest together those forms which are most alike, while it separates proportionately those which differ more or less from one another. Hence, in general, the most useful classification is that which indicates most truly the degrees of difference and resemblance by its manner of grouping the objects classified. To construct a classification of plants which shall meet this important condition as fully as possible has long been one of the chief tasks of the science of botany. Indeed, so important has the solution of this great problem seemed to botanists that until comparatively recent times it has en- gaged their attention almost exclusively. From their labors has at last resulted a classification which, although still incomplete in certain parts, is yet wonderfully adequate in its main features; and whether we consider the vastness of the undertaking or the success already attained, we must recognize it as one of the greatest achievements of the human mind. By its means to-day the student is enabled to gain a wider and deeper knowledge of the world of plants than was ever possible to the most learned botanist of former times. In the remaining chapters one of our chief aims will be to advance toward a general idea of modern systematic botany. Thus far in our study of useful plants, it has been most helpful to arrange them according to their uses; and it was sufficient for our purpose to mention merely incidentally 305 306 CLASSIFICATION AND DESCRIPTION the family or other group to which botanists assigned each plant under consideration, leaving the resemblances and differences thus indicated to be realized more or less vaguely by the student. What was then vague we shall strive now to make more definite, and the student may be assured that very much of what he has been learning about economic plants will prove of service in the present study. 83. Early attempts at classifying. Perhaps the reader may ask why it is not sufficient for all purposes of study to classify plants according to their uses, somewhat as we have been do- ing. Such a method of classification was indeed employed by some of the earlier writers upon plants; and this was quite natural, since, as we have seen, they were concerned chiefly with plants in their relation to human welfare. But granting that every plant may be of some use (even though not yet discovered) we know that many are useful in more ways than one. Consequently, any classification according to uses would often have to include the same plant in several different groups. Moreover, the great majority of plants are not put to any special use, and affect our welfare only in the same general way as do the economic ones apart from their special uses. Hence, any attempt to classify all plants ac- cording to use would require us to have besides the economic groups, one general group that would include all plants; and in the subdivision of this group we should be face to face with the original problem. One of the earliest attempts to avoid this difficulty was a division into herbs, shrubs, and trees. This grouping accord- ing to size and general appearance was a step in the right direction, and for certain purposes is found to be a serviceable arrangement even to-day. Yet, aside from the objection that when applied to all known plants each group includes an enormous number of sorts, there is the further disadvan- tage that such a classification requires one to place in differ- ent groups plants which resemble one another more closely than they do any others of the group in whieh they are placed. Thus, for example, certain oaks which are nothing but shrubs would on that account be separated from all the other oaks which are trees; the same is true of willows and of many ARTIFICIAL SYSTEMS 307 other genera that might be mentioned. Crude as this ar- rangement was, it afforded for many generations the best general classification of plants that anyone had to offer; and it was not until after the revival of learning in Europe, dur- ing the sixteenth century, that any important efforts were made to find a better way. 84. Artificial systems. An attempt was made to over- come the above objection regarding unnatural separation of sorts much alike, by calling the larger shrubs, trees, and the smaller ones, herbs, thus doing away altogether with the intermediate division. This, of course, lessened the difficulty in a way, but can hardly be said to have removed it. To make smaller groups, these two were again subdivided according to differences observed in this or that part. Thus, some writers made subdivisions according to the shape or arrangement of the leaves; others according to the form of the fruit or seeds; others still, according to peculiarities of some part of the flower; and so on, each writer basing his system upon characters taken from one or two parts. Many attempts of this sort were made during the next two centuries. Some of these systems were decided improvements over the earlier classification, but even the most elaborate of them had the same fundamental weakness already pointed out in the arrangement according to size. We know that plants which differ a good deal as regards a single part may be very much alike in all other respects, while plants much alike in a certain part may be otherwise very different from one another. For example, the fruits of the almond and the peach differ much in appearance when ripe, but otherwise an almond-tree and a peach-tree are almost exactly alike. On the other hand, the root of the beet and of the turnip are often of exactly the same shape, while the plants are strik- ingly different in all other respects. It is plain, therefore, that any arrangement of plants based upon a single character or very limited set of peculiarities, is bound to be unsatis- factory, because it cannot accomplish the chief purpose of a classification, namelv, to group nearest together the sorts that are most alike. In a word, these systems failed chiefly because they are artificial, and so not well calculated to ex- 308 CLASSIFICATION AND DESCRIPTION press the resemblances and differences among plants as we find them in nature. On the whole, as we have said, these artificial systems served to advance botanical knowledge; although after a while the inereasing number of them became a serious burden to all who studied plants. Any system, it was thought, if only used by all, would be much better than having to use so many. At last a practical way out of the increasing confusion was found by the eclear-sighted Linnzeus who came to the rescue much as he had done in the matter of plant names. 85. The Linnean system. The great need for some system which would be used by botanists in general, could, of course, be met only by a classification that was more convenient than any of those alreacy proposed. Linnzeus was the first to see clearly that the necessary convenience could not be expected in his day from any attempt at a natural arrange- ment, for the plants to be arranged were as yet very im- perfectly known. His predecessors had tried to produce a natural classification on an artificial basis, with results that were neither natural nor convenient. He aimed first of all at convenience, and to this end adopted a frankly artificial basis; yet in spite of this, as we shall see, his system proved to be more natural in many ways than any previously pro- posed. In the Linnean system, the old division into herbs and trees was entirely abandoned; all plants were divided into twenty-four “classes,” aecording to the presence, number, or form of certain essential parts (pistils) of the flower; and these classes were so grouped that all flowering plants were separated from those which have no true flowers. The latter constituted Class 24, Cryplogamia or cryptogams, which includes all plants such as seaweeds, mushrooms, mosses, and ferns, that are either destitute of parts such as we find in flowers, or if anything corresponding to such parts are present they are hidden from our unaided sight. The other twenty-three classes include all plants in which floral parts essential to the formation of seed, are manifest,—such ' Crvp-to-ga/-mia < Cr. kyryplos, hidden. THE LINN/HAN SYSTEM 309 plants as are now often known as Phenogamia ' or phenogams. Fach class was again divided into several “orders’”’ mostly according to the number, ete., of the other essential organs (stamens) of the flower. Under these orders Linnzeus grouped all the genera and species of plants known in his day. The distinctions upon which Linnzeus depended were so easy to understand and remember, and afforded such a con- venient means of classifying any plant, that the system soon gained an immense popularity, especially in England, and led to a widespread study of plants. Moreover, in his time, explorations in various parts of the world were bringing to light a great many kinds of plants and animals, previously unknown; and as Linnweus had also published a convenient classification of animals, most of those new discoveries were sent to him to name and classify. On the foundations so broadly laid systematic botany progressed much more rapidly and better than ever before, and during more than half a century the system of Linneeus remained practically the only one in use. We have said that although deliberately artificial, the Linnean system was remarkably natural in many respects. This is shown in the separation of the eryptogamic from the phenogamic plants; also in the faet that the species of a genus were always kept together, and in the association of many of the genera into orders corresponding to certain of the families recognized to-day. To understand why this is, we must remember that plants which resemble each other in one particular have very gen- erally other points of resemblance as well; hence, almost any artificial svstem is bound to be natural to some extent, and to what extent will depend on how far the characters chosen imply other points of resemblance. The reason why the Linnean system was so natural, was that its founder had the sagacity to choose his characters primarily from the essential parts of the flower; for likeness in these parts in- volves a great deal of similarity in other respects. Thus, the 1 Phe-no-ga’-mi-a (written also Phzenogamia and Phanerogamia) < Gr. phaino, to be manifest; gamos, marriage: because the floral organs essential to the production of seed are manifest. 310 CLASSIFICATION AND DESCRIPTION possession of true flowers implies the formation of seeds, and this in turn generally involves an elaborateness of struc- ture in the plant as a whole far greater than is found in cryptogamic plants, which, as we know, lack true flowers and seeds; while among flowering plants it constantly hap- pens (as the reader has doubtlessly already noticed in such familiar examples as the apple, pear, and quince) that close resemblance in the form of the seed-producing parts of the flower goes with fundamental similarity in all other parts of the plant. With all these advantages it is no wonder that this re- markable system should have exerted the wide influence which it did; but after all it was too artificial to serve per- manently as a final solution of the great problem of sys- tematic botany. Thus, for example, the group with two stamens and one pistil includes such widely different plants as olive and sage, while sage is kept far removed from other mints because they have four stamens. No one realized more fully than Linneus that his system was at best but a make- shift, fit only to serve the temporary needs of the science until botanists should be more extensively and more thor- oughly acquainted with plants than would be possible for many years to come; and he regarded his work only as a stepping-stone to the final achievement of an adequate clas- sification. 86. The natural system. As a contribution to the nat- ural system which he firmly believed would be developed in course of time, Linnzeus published a series of sixty-seven groups of genera which he called ‘‘natural orders.’’ He con- fessed his inability to define these groups by giving characters which would apply to all the genera of an order, and at the same time serve to separate the orders one from another; and left it for future botanists to discover how far the groups he had suggested really express the fundamental resem- blances and differences found in nature. The fuller knowl- edge of later times has largely justified a good share of these groupings; not a few of Linnweus’ natural orders are substantially equivalent to families recognized to-day, and have a place in modern classification often under the THE NATURAL SYSTEM 311 same or similar names. As examples may be mentioned the Palme or palms, Gramina or grasses, Orchidee or or- chids, Composite or composites, Conifere or conifers, and Filices or ferns. During the life-time of Linnzeus, the only other important attempt at a natural classification was made by Bernard de Jussieu, of France, who was a correspondent of Linnzus, and was in charge of the royal botanic garden at Trianon. Here he grouped the plants as far as he could in natural orders, but he published nothing. In 1789, two years after the death of Linnzeus, Antoine Laurent de Jussieu, nephew of Bernard, published a classification of genera under natural orders, one hundred in number. These were carefully de- fined by suitable characters, and thus constituted the first thoroughgoing attempt at a natural system. Not only were the genera grouped into well-defined orders, but the attempt was made to group the orders into higher and higher series, expressive of their degrees of likeness. On the foundation thus laid over a century ago the natural system now in general use has been slowly developing; the work of improvement is still going on, and more rapidly than ever before. Eventually the science of botany may boast of a systematic classification founded upon, and, in a way, expressing, a full knowledge of vegetable forms. Yet, as we shall hope to show in a future chapter, there are good reasons for believing that such an ideal classification will embody in very large part the distinctions at present recog- nized, or in other words, that the main features of a truly natural system are fairly well established. The next genera- tion of botanists will doubtless have the advantage of a far better classification, especially of cryptogams, than that in use to-day; but we may well believe that their classification will be essentially the same in general principle and in its main features as that now used. To develop the present system has been a gigantic task, beset with many difficulties; and before we can rightly understand the outcome of all this botanical labor, we must consider still further the diffi- culties overcome. Until we have mastered certain of these ourselves we are not fitted either to appreciate or to use to 312 CLASSIFICATION AND DESCRIPTION best advantage the important results which botanists have achieved in systematic classification. 87. Technical description. One of the most serious diffi- culties with which the earlier botanists had to contend was the problem of giving one another a clear idea of what each had seen. It is plain that so long as they failed in this, their discoveries were of little consequence. At first sight it may seem a sinple matter enough to tell what one sees, and be- ginners often wonder why botanists use so many peculiar words in their descriptions. ‘What is the reason,” they ask, “that ordinary English is not sufficient for the purpose?” If the reader has ever attempted to use ‘ordinary English” in the way proposed, he will realize that it is far from easy to give a clear account of the peculiarities of a plant in that way. The result is much as when a landsman ignorant of nautical terms tries to describe the features of a vessel so that it may be recognized. Success may not be impossible, but such a method of going to work is at its best clumsy, roundabout, and misleading. It was largely because the early botanists had nothing better to use than the ordinary language of their day, that it often proved impossible for others to tell what the plants were that they had tried to describe. But little progress towards a satisfactory classification of plants could be expected as long as descriptions were so vague and incom- plete as to be largely unintelligible. Since an ideal botanical classification represents, as we have seen, the expression of all the resemblances and differ- ences among plants, its attainment must involve the use of words especially fitted to express unmistakably all the pe- culiarities that may be observed. Each part must have a special name, and the innumerable forms and features of each part must be indicated by simple words or phrases. Ordinary language has not been developed to serve any such botanical purposes any more than it has to serve similar nautical needs; hence, botaiists have been forced to make a language of their own consisting largely of technical terms. 88. Early attempts at describing. Before the time of Limneus, the attempt was made by many botanical writers to avoid the language difficulty by the use of pictures to LINNAZAN REFORM IN TERMINOLOGY © 313 show what they meant, much as we have done in the fore- going chapters. A good picture is certainly to be preferred to a description that is not understood; but a little thought will show that pictures, however good they may be, cannot solve the whole difficulty. We cannot make a picture of a species, but merely of a single individual; and our conception of a species must be our idea of the features which all its individuals have in common. A number of pictures of dif- ferent individuals might convey more of this idea, but even then peculiarities perceptible only by touch, taste, or smell could be indicated only by words. Moreover, even features that may be represented in a picture generally need the help of words to point out what especially calls for attention; and when species are compared and classified one arrives at important general ideas which cannot be pictorially expressed. Add to these shortcomings the greater labor and expense involved in publishing pictures, and it becomes evident that verbal means are needed. For centuries, as we know, all learned works were written in Latin; consequently, it was from this language that the botanical terms were primarily taken. These were often common words to which a meaning was attached differing from the ordinary one, more or less, in its application; or, sometimes new words had to be coined and this was fre- quently done by latinizing words or combinations of words taken from the Greek. As with the early attempts at forming systems of classi- fication, so in the development of a botanical terminology or technical vocabulary, different writers went about the matter in different ways; and such independence of action naturally led in this case also to a good deal of confusion. From this embarrassment of riches, which threatened to be a serious hindrance to further progress, Linnzus, again, found the best means of practical relief, Just as he did in the matter of classification and nomenclature. 89. The Linnean reform in terminology. Being thoroughly familiar with the botanical writings of his predecessors, and endowed with a fine sense of fitness in language, Linn:eus was able to choose the best terms which had come into use, 314 CLASSIFICATION AND DESCRIPTION define them in a convenient way, and add others so far as necessary. The publication of this carefully prepared vo- cabulary gave the necessary material for making botanical description henceforward an art, while in his systematic writings Linneeus left examples of the art, well calculated to serve as models of excellence. In describing a plant his ideal was to state all that was necessary and nothing that was unnecessary to distinguish it from all other plants. Since the time of Linnzeus, botanical terminology has been enriched and improved in various ways to meet the needs which have arisen with wider knowledge; but the art of describing plants still remains very largely what its first great master made it. Pictures are no longer deemed neces- sary to make up for vagueness of description; when it is possible to use them, their scientifie value is much increased because what they lack may be supplied in words, and the significance of what is represented can be made plain. In- deed, to one familiar with the terms used, a complete bo- tanical description calls up so clear a mental picture of each part described, that a drawing sufficiently accurate for recog- nition might often be made even though no specimen of the plant had ever been seen. Surely this is a triumph such as ordinary language has never attained. 90. Terminology and nomenclature. Persons who have only a superficial acquaintance with botany are apt to think of it merely as a study of names, which hinder rather than help one in learning whatever botanists may know of general interest about plants. Doubtless the student of the fore- going chapters already feels that this is far from true; yet this false opinion conceals a truth which it will be worth while for us to consider. Special names and descriptive expressions of various sorts do occupy a prominent place in the scientifie study of plants, and these botanical technicalities doubtless present a more formidable appearance than the special terms of most other sciences. Yet, paradoxical as it may seem, the very fact that botanists use these means of expressing themselves, makes it much easier for a beginner to arrive at an under- standing of what they have to say, and so to a knowledge of TERMINOLOGY AND NOMENCLATURE © 315 plants, than would otherwise be possible. The unusual fullness of their special vocabulary enables botanists to tell what they know in the fewest possible words and with least danger of being misunderstood. False ideas are the greatest hindrance to the pursuit of knowledge; and whatever will lessen the danger of these, especially to the beginner, is sure to save labor in the end. We have already seen (page 4) that the practice of hav- ing a double name for each species, instead of giving twice as much to remember as if the name of each sort were a single word, almost halves the burden upon one’s memory that one-word names would impose. The ease with which words are remembered depends, as we know, largely upon how frequently the word is encountered; hence, the student is helped not a little by the circumstance that a large majority of specific names are the very words from which the descrip- tive terms in common use have been derived. Further- more, these descriptive terms, as well as the names of the parts of plants and of genera and other groups, are in large part made up of a comparatively small number of Latin and Greek words, which once Jearned serve as helpful aids to the memory, and, indeed, often enable the student to tell at sight the meaning of a new botanical word. In our study of systematic botany we shall learn the more important descriptive terms as we need them in de- veloping a general idea of the natural classification of plants. The student will learn how to distinguish some of the more important families and higher groups, so that when he ex- amines a plant he can tell at least the sub-kingdom to which it belongs, usually also the class, sometimes the order, often the family, and in certain cases even the genus and species. At first we shall confine our study to those plants which produce flowers and seeds, leaving for later consideration the groups including ferns, mosses, lichens, mushrooms, and sea- weeds. CHAPTER VIII THE PARTS OF A SEED-PLANT 91. Flaxasatype. De Candolle, one of the most learned of French botanists, was wont to say that he could teach all he knew of botany from a handful of plants. What he had in mind was doubtless the great truth that among the resemblances of plants to one another there are some of such fundamental importance that it becomes possible to discern amid the endless variety of forms a few plans of structure upon which all plants are built. His handful of specimens would have been so chosen that each might exhibit especially well the features common to many kinds, and thus serve at once as a convenient standard of comparison and as a means of teaching truths of very wide application. A form which in this way is representative or typical of any group, natural- ists call a type. Flax (Figs. 217 [, U1) will serve well as our type of phen- ogams or seed-plants because it possesses all the parts which they commonly show, and exhibits them in comparatively unmodified condition. Like all true flowering plants it pro- duces seeds. 92. The seed may be compared roughly to an egg. Much as ina hen’s egg, for example, we have the shell covering a mass of food material provided for the chick or germ which hes within it, so im the sced (Fig. 279A) we find a protective seed-coat (c) enclosing secd-food (f) and a germ or embryo } (e). Much of the food provided for the flax embryo is already stored within the little plant itself; what remains to be ab- sorbed has been hkened to the white of egg and is called the albumen ® of the seed. The embryo within the seed is found 1Em'bry-o < Gr. embryon, germ. 2 Al-bu’men < L. albus, white. B16 THE PARTS OF A SEED-PLANT 17 upon careful examination to be already a miniature plant, for it has a stem (s) bearing at its lower end the beginning of a root (vr) which becomes apparent when the seed sprouts; while at the upper end of the stem are borne a pair of fleshy leaves (1) which after sprouting turn green, and between them a tiny bud (b) which is destined to grow into the stem, leaves, flowers, and fruit of the mature plant. Each of these parts of the embryo has been given a special name. The little stem which bears all the other parts is the caulicle.t Each of the first leaves is a cotyledon.2. The bud at the top of the caulicle is known as the plumule,’ while the rudimen- tary root at the lower end is called the radicle. 93. The seedling and its development. When the seed germinates, the radicle is the first part to appear (Fig. 279B). Soon it grows into a root (Fig. 279C) covered with hairs through which absorption of soil-water takes place. Mean- while the cotyledons have been feeding upon the albumen to get material for their growth and for the elongation of the eaulicle and root; and when finally this reserve food is ex- hausted, the empty seed-coat is cast off, the cotyledons become green and expand in the sunlight (Fig. 279D), and the plumule develops into a leafy shoot (Fig. 279E). As the root pene- trates downwards into the soil it sends forth branches in various directions (Fig. 2171). At the same time the leafy shoot grows upward developing stem and leaves by the con- tinual unfolding of a bud at its tip which began as the plumule (Fig. 279F). The place at which a leaf joins the stem is called a node,’ and the length of stem between two nodes, an itnternode.* 1 Caul’i-cle < L. cauliculus, diminutive of caulis, stalk < Gr. kaulos, stalk. 2 Cot-y-le’don < Gr. kolyle, a shallow cup, which some cotyledons are supposed to resemble. ; ; ’ Plum’ule < L. plumula, a little plume, which the plumule of certain plants, such as the peanut or almond, somewhat resemble. 41Rad‘i-cle < L. radiculus, diminutive of radiz, a root. The term radicle is sometimes used so as to include the caulicle, and caulicle is sometimes made to include the radicle as above defined; but the terms are coming to be understood in the sense here adopted. » Node < L. nodus, a knot, the joint being likened to a knot in a cord. 6 In-‘ter-node < L. inter, between. 318 THE PARTS OF A SEED-PLANT p) 4 Y\ SS Q \ ‘ ees \ Abyty We o Tray Og J uy EB Tig, 279.—Flax Germination. A, seed, cut vertically to show the seed- cout (c), seed-food (f), embryo (e), with its seed-leaves (1), seed-bud (b), seed-stem (s) and seed-root (r). B, seed beginning to sprout; the seed- PHYSIOLOGICAL DIVISION OF LABOR 319 After a while new buds appear on the sides of the stem at points Just above the nodes (Fig. 280), that is to say, in the axil' or upper angle between leaf and stem; and these buds as they expand become lateral branches, which in turn may branch similarly. Finally, some of these buds, instead of producing more foliage, develop flowers (Fig. 2171). 94. The flower and the fruit. In the center of the flower (Fig. 21711) we find a pistil? containing ovules * within an ovary ‘from the top of which grow five styles 5 each terminat- ing in a stigma.6 Around the pistil are five stamens,’ each producing pollen * within an anther® borne on a slender filament.° Enveloping the stamens are five petals 4 and five sepals.1? Pollen falling upon the stigmas, brings about the development of the ovules into seeds while the ovary ripens into a fruit. Pistils and stamens thus being essential to the production of seed are called the essential organs of the flower, while the petals and sepals, more or less enveloping them, are called the floral envelops or pertanth. 95. Physiological division of labor. Even such a cursory examination as we have made of our typical plant is sufficient 1 Ax’-il < L. axilla, arm-pit. 2 Pis’-til < L. pistillum, a pestle, such as apothecaries use for pound- ing drugs in a mortar, pistils often resembling pestles more or less in form. ’O/-vule < L. ovulum, diminutive of ovum, an egg. 4 Ovy’-ar-y < L. ova, plural of ovum; ary, repository. * Style < Gr. stylos, a pillar. 6 Stig’ma < Gr. stigma, a spot. 7Sta’men < Gr. stamon, a thread. 8 Pol’len < L. pollen, fine dust. 9 An’ther < Gr. anthein, to blossom. 10 Fil’a-ment < L. filum, thread. 1 Pet’al < Gr. petalos, outspread. 12 Sep’al < L. separ, separate, different. 13 Per’i-anth < Gr. peri, around; anthos, flower. stem (caulicle) has just pushed through the seed-coat and is pushing the seed-root (radicle) into the ground. C, later stage in which the radicle has elongated and produced root-hairs, while the caulicle has pushed up the seed. D, still later stage in which the caulicle has become further elongated and arched and the seed-leaves or cotyledons are growing out of the seed. E, plantlet showing pair of cotyledons ex- panded and ready to act like leaves; also three pairs of primary leaves and a stem developed from the seed-bud or plumule. F, plantlet still older, showing, in addition, secondary leaves, formed one at a joint. (Original.) 320 THE PARTS OF A SEED-PLANT to show not a little variety and complexity in the different parts which compose it, and one is aware that much more complexity of structure would appear upon further study. But why the plant should have such a complex structure may not be at first so obvious. We are helped to an under- standing of the matter, however, by remembering that wherever there is much variety of work to be performed, it is an advantage to have the labor divided among different sets of workers, each fitted for their special share and codperat- Fig. 280.—Flax Bud cut vertically and much enlarged to show the develop- ment of the leaves from protrusions arising at the side of the dome- like stem-tip which cousists of formative material. (Original.) ing with the rest. This principle is shown clearly in the com- munity to which we belong, where the labor of meeting the needs of the people as a whole is divided among farmers, miners, manufacturers, merchants, soldiers, teachers, and many other classes, while in each class the work is divided and subdivided again and again. The degree of specialization and codperation found in such advanced communities as our own chiefly distinguishes them, as we know, from such less advanced communities as the Indian tribes which preceded us upon the American continent; and we say that this was ORGANS AND THEIR FUNCTIONS 321 largely because their conditions of life were simpler and so their needs less than ours. Similarly we should find the higher plants, such as flax, contrasted most significantly with such lower forms as Irish moss in the extent to which they exhibit a differentiation of parts and mutual helpfulness throughout; and we should find a similar reason to hold good. Accordingly, we may not inaptly compare the roots, the stem and its branches, the leaves, and the parts of the flowers and fruit of our plant to the various classes of workers which we find in a civilized community, since the work of the whole is similarly divided among the parts and all labor for the common good. It is such an idea as this that naturalists have in mind when they speak of the phystological division of labor observable in a plant or an animal. 96. Organs and their functions. In either a plant or an animal any part having a special office to perform is called an organ,! the special office being known as its function. Thus the root of our flax-plant is an organ the chief function of which is to absorb mineral substances from the soil. The function of the stem is mainly to support its leaves, flowers, and fruit advantageously; while the general function of its floral organs is to insure the production of good seed; and the function of its fruit is to bring about their dispersal. We often find the same function performed by different organs which are curiously unlike in other respects, as for example the function of support as performed by the tendrils of the pea (Fig. 37), the climbing roots of the poison-ivy (Fig. 210), and the grappling prickles of the rattan (Figs. 2231, II). Organs which agree in function are said to be ana- logues* of one another, or to be analogous. According to their main functions the parts of our typical plant may be classified conveniently as organs of nutrition (e. g., the root, foliage, leaves, and cotyledons); of support (the stem and its branches); of protection (the bark); of reproduction (the 1Or’gan < Gr. organon, an instrument or tool. Since animals and plants are made up of organs they are called organisms, and the mate- rials which are present in them alone are called organic, to distinguish them from inorganic or mineral substances. 2Fune’tion < L. functio, performance. 3 An’-a-logue < Gr. ana, according to, logos, relation. 322 THE PARTS OF A SEED-PLANT flower); and of dissemination (the fruit). The first three of these groups, since they have to do primarily with the individual life of the plant, form what is called the vegetative system, while the others being concerned only with propaga- tion and the care of offspring constitute the reproductive system. 97. Morphological differentiation. From what has been said of the life history of flax it is plain that the differentiation of its parts progresses as the plant grows older. We saw that the parts of the embryo within the seed are all much alike, as are also the young foliage leaves and floral organs within the bud; but as the plant matures and its needs become more varied the parts come to have different functions to perform and take on the various forms which fit them for their special kinds of work. Thus, the mature flax differs from the same plant in its infancy much as do the higher plants from the lower. But in spite of the progressive differ- entiation shown by a growing plant we feel that even its more highly specialized organs correspond somehow in a fundamental way with certain of the earlier or less specialized ones. Petals, for example, although widely different from cotyledons in function, are yet in some ways so much like them and like ordinary foliage leaves that cotyledons are often called ‘‘seed-leaves”’ while petals are familiarly known as “leaves of the flower.’ So, too, in comparing the parts of different plants we often find a fundamental likeness along with marked differences in function. Thus, the climbing roots of the ivy before mentioned are essentially the same in important particulars as the absorbing roots of flax. Not only among plants but also among animals it is true that analogous organs may show important differences, and similarly that organs which are not analogous may be essen- tially alike as holding corresponding places in the funda- mental plan of structure. A man’s arm viewed as an organ for grasping is plainly the analogue of an elephant’s trunk, and an opossum’s tail; while viewed as a member of the body it corresponds to the fore leg of a horse, the flipper of a whale, and the wing of an eagle. Considerations of this MEMBERS OF THE PLANT BODY 323 nature lead us to inquire; What is the fundamental plan of structure exhibited by our typical plant? and What may we rightly regard as the members of such a plant-body? 98. Morphological units. We have seen that the embryo flax is a miniature plant already possessing a stem-part, rudimentary leaves, and the beginning of a root. These parts we recognize as representing the main divisions of the plant, at least before it flowers, for we know that for many weeks as the plantlet grows it simply produces more root, more stem, and more leaves. If we examine minutely one of the leaf-buds (Fig. 280) we find it to contain a series of young leaves which are smaller and smaller as we approach the tip of the stem until finally they appear as mere lobes. Thus we see that a leafy shoot begins as a tiny dome- shaped mass of growing material, which as it elongates, be- comes differentiated into (1) lateral lobes, which grow into leaves, and (2) a central or axial part constituting the stem which bears them. Soon in the axils of the young leaves appear growing points like the cone at the tip, and each of these becomes a bud which may develop into a leafy branch. Since corresponding parts arise at regular intervals, the whole shoot, especially as it grows older, takes the form of a series of segments or equivalent divisions each consisting of a leaf-part borne by. a stem-section from which a bud or rudimentary branch may also develop. The embryo, we remember, had just these parts, and in addition bore a root. Often, such a shoot-segment cut from a plant and placed under favorable conditions for growth will send out a root, and develop other segments much as an embryo does; and, commonly, a cutting which consists of a single leaf attached to a bit of stem, is the least part of a flowering plant that can be made to grow independently. Hence such a seg- ment consisting of an internode and its node, together with the leaf or leaves it bears, has been regarded as constituting, in a way, a unit of plant structure. 99. Members of the plant body. A plant like flax is some- times thought of as a colony of segments or in other words as a community of closely connected individuals each con- sisting of a stem-part and leaf-part, and capable of producing 324 THE PARTS OF A SEED-PLANT aroot, and so leading an independent existence. On this view each segment would correspond to an individual animal and its leaf-part and stem-part would be likened to the members of the animal bocly, such as the trunk and the limbs. With- out accepting this extreme view of what constitutes an individual plant—a view not in accord with what we have learned about the development of the shoot—it may still be convenient to regard the bodies of the higher plants as built up of segments, much as zodlogists regard the bodies of many segmented animals like earth-worms and lobsters as consisting of a series of roughly comparable units; and, similarly, just as the limb of an animal viewed as one of the main clivisions of the body or of a segment is called a member, so the main divisions of a plant-segment—the stem, the leaf, and the root—viewed not as organs but merely as parts differing in origin and position, may be conveniently dis- tinguished as members of the plant body. But the question at once arises, supposing it to be admitted that the vegetating plant may be roughly likened to a many- storied building, each story being a segment, and the whole supported on a root foundation, can we yet find correspond- ing units of structure in the flower? If the flower is com- posed of segments it is evident that the different members must be more or less disguised. As regards the floral envel- opes we have already seen that their leaf-like nature is so thinly disguised that they are commonly recognized as “leaves of the flower.”” Indeed, we have only to suppose the internodes of the stem-parts to have remained as short as they were in the bud, while the leaf-parts expanded, to see that so far as origin and relative position are concerned, the floral envelopes are essentially like a leaf-rosette. But the stamens and the pistil present greater difficulties. Still, | I when we come to compare other flowers with those of the flax, we shall find much evidence going to show that even stamens and pistils correspond in large part to leaves. One sort of evidence—not indeed conclusive, but yet significant— is the occurrence now and then of monstrous flowers in which actual green leaves occupy the place of the stamens and pistil, much as if the organs had determined to throw off all dis- MEMBERS OF THE PLANT BODY 325 guise and exhibit their true nature.!. The proof of a theory is in the using; for the present it will be enough for us to have gotten a preliminary idea of what the segment theory means when applied to our typical plant. Other questions, closely connected with the foregoing one, are, What members may a segment have? and, How may. these be distinguished under all their disguises? The flax embryo, as we have seen, represents a segment reduced to about its simplest terms. We here recognize an axial member bearing lateral members,—the stem-part and the leaf-part,— one implying the other. When the root-part appears we have another member which is also axial, but differs from the stem in being without leaves. As the root elongates there appear near its tip numerous hair-like projections which differ essentially from leaves in being merely superficial outgrowths not continuous with the innermost parts as is the case with leaves. Superficial appendages of this sort often occur in other plants on the stem and leaves as well as on the root. Such more or less hair-like outgrowths are best regarded as parts of members rather than as members. In the essential organs of the flower we meet with a difficulty regarding the real nature of the pollen-sacs and ovules or egg-sacs as we may call them. In the flax they both might be taken to be parts of the peculiar leaves which we regard as forming the stamens and pistil. But there are other plants, as we shall see, in which an ovule appears on the very tip of the stem or axis, while in some cases pollen-sacs seem to grow directly from the stem. We can then hardly call such organs parts of a leaf. On this account and for other reasons 1 The theory of floral structure which likens a flower to a leaf-rosette originated with the poet Goethe to whom it was suggested by seeing a green rose such as occasionally appears in gardens. This theory has proved to be a helpful means of understanding the relation of the various parts of plants to the fundamental plan of structure; but as it tells only part of the truth it has been somewhat misleading, and it requires to be modified considerably from its original form to be in accord with more recent views of vegetable morphology. As developed above, however, it is believed that the theory will be found to avoid the un- warranted assumptions which have brought into it discredit, and to_re- tain the features which have made it useful, while at the same time such modifications are made as will render it a valuable means of con- veying modern views. 326 THE PARTS OF A SEED-PLANT which will appear later, we are led to regard both pollen-sacs and egg-sacs as distinct members of the plant body. We thus come to the conclusion that our typical plant viewed morphologically is made up of members of the nature of stem, leaf, root, pollen-sac, and egg-sac; and that the whole body may be furthermore regarded as consisting of a chain of segments, each segment having at least a stem-part and a leaf-part and sometimes also other members. A root-member may be defined in a general way as typically a descending axis; a stem-member as an ascending leafy axis; and a leaf-member as a lateral, transversely flattened out- growth from a stem. Since stems and leaves imply one an- other, it is convenient to speak of them together as forming a shoot. Thus in our flax embryo the caulicle, cotyledons, and plumule constitute the shoot as distinguished from the root-part. A sac-member, such as a pollen-sac or an egg-sac, is really, as we shall see later, a spore-case essentially like that of Lycopodium (Fig. 166,2). Pollen grains are spores; and each egg-sac contains one or more comparatively large spores within which an embryo arises. Thus a sac-member is known by what it produces. As to how these different members may be further distinguished we shall learn more fully when we come to compare other plants with our type. 100. Homologies. We have already seen that the terms analogy, analogue, and analogous, afford us a means of ex- pressing physiological equivalence or similarity in function. To express morphological correspondence or similarity in origin and position naturalists use the companion terms homology,! homologue, homologous. Members of the same sort are said to be homologues of one another; any form of leaf-member, for instance, being homologous with any other form. Cotyledons and petals are homologues, because both are leaf-members, and they would accordingly be spoken of as homologous parts, homologous organs, or homologous members. The principal parts of our typical plant and their homologies as here understood are indicated in the accom- panying diagram (Fig. 281). The tracing of homologies forms the basis of morphology, ' To-mol’o-gy Ver’-ti-cil << L. verticillus, the whirl or whorl of a spindle, which is a disk-like piece of wood or metal encircling it; hence, in botany a ring of parts similar to one another encircling an axis. *Sub-tend’ < L. sub, under; tendere, stretch. THE REPRODUCTIVE SYSTEM 343 to it. Traces of this flattening may be observed commonly even in the petiole on the upper or inner surface, especially near the base. These tests applied to the foliage of colum- bines, for example, will show why it must be considered as made up of branched leaves—decompound leaves with many leaflets—rather than a branched stem bearing many simple leaves. The stem and leaves of the marsh-marigold, as of marsh- loving plants in general, are quite smooth and unprovided with any hairy or other protective covering. Plants or parts in this condition are described as glabrous. When covered with soft, downy hair they are said to be pubescent.2. Many ranunculaceous plants, especially those growing in dry, sunny places (as for example the pasque-flower, the tall crowfoot, and the bulbous crowfoot) are pubescent, particularly when young. 103. The reproductive system. Turning now to the flowers of the marsh-marigold it will be noticed that they grow either at the tip of the main axis or on stalks which arise from the axils of upper leaves. On the side of the flower-stalks, or subtending them, may be sessile leaves or more or less scale-like leaf-members. Such leaves subtending a flower or a flower-cluster are called bracts,* or when borne upon a flower-stalk they are termed bractlets. The stalk of a flower or flower-cluster is distinguished as its peduncle.‘ We speak of a blossom or flower-cluster as an inflorescence.’ Thus we say that the inflorescence of the marsh-marigold consists of a terminal flower, and a few axillary ones, with bracts and sometimes bractlets. It should be noted that the terminal flower opens before the lateral ones, thus putting an end to further elongation of the main axis. Such an in- florescence is therefore called determinate. It is also de- scribed as cymose because the form of cluster which typically results from the determinate mode of growth is called a 1Qla’-brous < L. glaber, without hair. 2 Pu-bes’-cent < L. puber, downy. 3 Bract < L. bractea, a thin plate. 4 Pe-dun’-cle < L. pedunculus, diminutive of pes, pedis, foot. 5 In-flor-es’-cence < L. in, in; florescere, begin to blossom, 344 THE CROWFOOT FAMILY cyme.! The inflorescence of the marsh-marigold is a simple cyme. A well-developed cyme is found in certain species of clematis. Here, as shown in Fig. 290, the axes repeatedly branch, making the cyme compound. In compound inflores- cences the ultimate flower-stalks are called pedicels.2. A whorl or cluster of bracts is an ¢nvolucre;* while the term involucel 4 is applied to a whorl of bractlets. Thus the wood-anemony has an involucre of three leaf-like bracts situated far below the solitary flower. These are called bracts because in related species bracts similarly placed subtend peduncles, although as must be obvious the distinction between bracts and bract- lets in such cases is rather arbitrary. Fennel-flower has an involucel of a few large bractlets very near the blossom. Most of the crowfoot family have simple, cymose inflores- cences, usually of only a few flowers as in crowfoots, colum- bines, and the Christmas rose. Often, even in the genera mentioned, the flowers may be solitary, and this is usually if not always the case in mouse-tails, anemonies, fennel-flowers, and peonies. In contrast with these determinate inflorescences in which the terminal, upper, or inner flowers are the older, are in- florescences of the indeterminate type shown in baneberries and monkshoods. Here the upper flowers are the younger, and the main axis or rachis®> may elongate indefinitely, developing new flowers as it grows. When, as in the ex- amples given, the main axis is longer than the peduncles, the cluster is termed a raceme.’ So typical is this of the indeterminate form of inflorescence that the term botryose ? of similar implication is given to it as being in significant contrast with cymose. From the above it appears that in describing and naming inflorescences botanists have regard either to the manner in 'Cyme < Gr. kyma, a young sprout, because the younger flowers arise like sprouts from below. (Pronounced siem.) > Ped’-i-cel << L. pedicellus, diminutive of pediculus, dim. of pes, pedis, foot. *In'-vo-lu-ere << L. ¢nvoluerum, < involvere, enwrap. ‘In-vol’-u-cel < Li. tnvolucellum, a little wrapper. ’Ra’-chis < Gr. rhachis, backbone. ® Ra-ceme’ < L. racemus, a bunch of grapes. ' Bot/-ry-ose < Gr. botrys, a bunch of grapes. THE REPRODUCTIVE SYSTEM 345 which the branches arise and the relative position of the oldest flowers, or else to the general form as modified by more obvious features, like the relative lengths of the internodes. It is desirable to keep these two points of view distinct. Viewed as to their system of branching, simple inflores- cences, such as most of those we have been studying, are either of the cymose or the botryose type. Under the head of cymose inflorescences we should include a solitary flower which terminates a leafy axis, as in the wood-anemony; while a solitary flower, which, like that of the mouse-tail, springs from the axil of a foliage leaf would more logically be called botryose. When the branches of an inflorescence branch again it becomes compound, as in our example of clematis, (Fig. 290) which has a compound cyme, or cyme of cymes. As to general form we may here distinguish: (1) racemose inflorescences or racemes, like those of monkshood and baneberry, which are simple and have pedicels all shorter than the rachis, thus giving an elongated cluster; (2) panicw- late } inflorescences or panicles, which are more or less elon- gated and compound, as in Fig. 293; and (3) corymbose * in- florescences or corymbs (Fig. 290) which have the outer pedicels or branches about as long as the rachis, and those nearer the center progressively shorter so that the cluster as a whole is broad and more or less flat-topped. Corymbs often become racemose as they grow older, and compound corymbs, paniculate. .Some botanists would restrict the terms raceme, panicle, and corymb to indeterminate in- florescences; but in practice these names are applied indis- criminately also to inflorescences of the determinate type which have assumed the forms above defined. Thus we may speak of a racemose, paniculate, or corymbose cyme. In a flower of marsh-marigold we recognize many organs similar to those already observed in the flax but with some important differences. Thus in the center of the flower we find a cluster of pistils each with a single stigma, style, and ovulary cavity instead of a single pistil with several styles and stigmas and a single ovary with several cavities. Such 1 Pan-ic’-u-late < L. panicula, a tuft. 2 Cor-ymb’-ose < L. corymbus, a cluster of flowers. 346 THE CROWFOOT FAMILY simple pistils as those of the marsh-marigold are called carpels' . and are regarded as representing each a single egg-sac leaf just as a stamen is a single pollen-sac leaf. Taken together the carpels form the gynecium? of the flower, while the stamens collectively form the andracium.’ Near the hase of each carpel is a gland that secretes drops of a sweet fluid, called nectar + which attracts insects, and from which they make honey. In each ovary of the marsh-marigold, as will be noticed, there are several ovules attached to that part of the wall lying nearest the center of the flower along a line running from top to bottom—such a line as would be made by the edges of a folded leaf where they came together. Thus the carpel of a marsh-marigold may be likened to a leaf bearing ovules along its edges and these joined so as to form an ovary. That part of an ovary wall which bears the ovules is called the placenta; * and when as in this case it extends along the front side of the ovary (that toward the center of the flower) the placenta is said to be ventral.s The oppo- site side or back of the carpellary leaf, commonly marked by a ridge representing the midrib, is distinguished as the dorsal? aspect. The ovules of marsh-marigolds are essentially like those of flax and of all the crowfoot family. We may distinguish in each ovule a little stalk, the fundele,* which continues as ¢ ridge, the raphe,® along the side of the main part or body of the ovule. At the small end is a minute opening, the micro- pyle.” An ovule which is bent so that the micropyle comes next to the funicle, or point of attachment, is termed anat- ropous."! — 'Car’-pel < Gr. karpos, fruit, as being essentially the fruit produc- ing part. * Gy-nee’-ci-um << Gr. gyne, female; oikos, house. § An-dree’-ci-um << Gr. andros, male. ‘4 Nee’-tar < Gr. neklar, the drink of the gods. » Pla-cen’-ta < L. a little cake, from its cake-like form in certain cases. 6 Ventral < L. renter, belly. 7 Dor’sal <1. dorswm, back. *Pu-ni-cle << L. fundeudus, diminutive of funis, a cord. "Ra’phe < Cr. rhaphe, a seam. " Mi-ero-pyle < Gr. micros, small; pyle, gate. ' A-nat’-ro-pous < Gr. ana, back; (repein, turn. THE REPRODUCTIVE SYSTEM 347 Gyneecia essentially like those of marsh-marigold are found in Christmas roses, columbines, peonies, and monks- hoods (Figs. 178, 282, 287, 284). In anemonies (Fig. 297), each carpel contains at first the rudiments of several ovules, but only one (the lowest) develops, the rest remaining mere rudiments.. Many genera, as for example, crowfoots, mouse- tails, meadow rues, and clematises (Figs. 285, 290, 293) have only asingle ovule in each carpel from the first. In afew cases it happens, as in fennel-flowers (Fig. 286) and certain species nearly related to the Christmas rose, that the carpels are more or less united with one another at the base, thus form- ing a compound pistil comparable to that of flax. As a result of this union of the carpels there is formed a single compound placenta which being at the center of the ovary is termed axile. It is obvious that a compound pistil, say of five carpels, requires less material than an equal number of separate carpels of the same size, just as it takes less bricks to build a chimney with five flues than it does to make for each flue a separate chimney. Almost all of the crowfoot family have simple pistils, 7. e., consisting of but one carpel. The number of simple pistils may be many, as in crowfoots, mouse-tails, and anemonies; several or few, as in Christmas rose, colum- bines, peonies, and monkshoods; or only one, as in bane- berries. When both stamens and pistils are present (as in nearly all of the crowfoot family) the flower is said to be perfect; it is imperfect when either set of essential organs is absent or rudi- mentary. Flowers having stamens alone are called staminate; those with pistils alone, pistillate. In certain species of clematis both perfect and imperfect flowers occur; such plants are termed polygamous. Andreecia consisting of an indefinite number of stamens like those of marsh-marigold occur in the wood-anemony, peonies, and certain species of clematis (Figs. 194, 282, 291). Among cultivated peonies we often find flowers which have be- come ‘‘double”’ as the gardeners say. In these the outer sta- 1 Perfect flowers are symbolized in botany by the sign 8, staminate by <, and pistillate by @. The expression 8 & @ would thus stand for polygamous. 348 THE CROWFOOT FAMILY mens are replaced by more or less petal-like leaf-members which, however, differ considerably in shape from the petals, and show clearly their closer homology with filaments by nu- merous intermediate forms (Figs. 294, 295). What here takes place as an abnormality throws light upon the homology of certain curious and puzzling organs often called ‘“nectar- leaves”? which take the place of the outer stamens in many flowers of the crowfoot family. In some anemonies—as in the wood-anemony—the outer stamens have anthers, while in other species like the pasque-flower the outer filaments are destitute of anthers but instead have swollen tips which secrete nectar (Figs. 194, 296 A). Antherless stamens are called staminodes.1 The nectar-leaves are most probably of this nature. The Christmas rose has tubular staminodes; the mouse-tail, staminodes somewhat club-shaped and bent; crowfoots have them broadly expanded and __ petal-like; fennel-flowers, more or less petal-like with a peculiar pouch; while in columbines there is an outer set of colored staminodes forming trumpet-like spurs which secrete nectar copiously, and next to the carpels two inner scts of five each which produce no nectar and are very thin and colorless (Figs. 284D, 28511, 296B-E). It is not unusual for botanists to speak of the petal-like nectar-leaves of this family as petals, but this is not in accord with the modern view of their homology. Most of the crowfoot family are like marsh-marigolds in having no corolla. In peonies are found unmistakable petals. These show that they belong to the perianth, not only by having a much wider base than the stamens, but also by the occurrence of transitional forms connecting them with sepals, as illustrated in Fig. 294. The series as there shown connects also sepals, bractlets, and bracts. Anemonies and fennel- flowers, as we have seen, have involucres or involucels which are sometimes so close to the flower as to be easily mistaken for calyx, and which indeed differ from calyces only in being separated from the floral whorls by a more or less developed internode. The case is especially deceptive when the sepals are petaloid, 7. e., brightly colored like petals, and the in- volucre is close to the flower. Flowers without a corolla are 1 Stam/-in-ode < L. stamen, staminis, stamen; Gr. etdos, a form. THE REPRODUCTIVE SYSTEM 349 said to be apetalous.!. When as in peonies the flowers have calyx, corolla, stamens, and pistils, they are described as complete. Many of the crowfoot family have the calyx petaloid, as in marsh-marigolds, anemonies, clematises, Christmas roses, fennel-flowers, baneberries, columbines, and monkshoods. In mouse-tails each of the sepals develops near the base a tubular pouch or spur (Fig. 285). Most commonly, the sepals, at least in the bud, overlap at the edges in such a way that some are wholly inside and some wholly outside, as shown in Figs. 282, 284. The sepals are then said to be imbricate,? and the same term applies to petals or similar organs thus overlapping. When the parts touch at the edges without overlapping, as for example the sepals of clematis (Fig. 290) they are valvate.*. The arrange- ment of floral parts in the bud is called their estivation; + of leaves, their vernation.® Almost all the flowers of the family have the parts of each whorl alike; that is, the carpels of a flower are repetitions of one another, likewise the stamens, the petals, and the sepals when present. Such flowers are called regular. A few of the family have zrregular flowers, as for example the monkshood (Fig. 178) so called from the peculiar cowl-like form of one of the sepals which is larger than the others and partially enwraps them. The hood covers also a pair of staminodal nectaries. The stamens with anthers and the gyncecium are regular. The stem part of the flower is called the torus * or receptacle. It represents the continuation of the flower-stalk or peduncle upon which the floral leaves grow. It is customary to speak of the way in which an organ is attached to its support as its insertion, or to say that the organ is inserted upon what- ever bears it. Thus we say that the andreecium and calyx 1 A-pet/al-ous < Gr. a, without, petalon, petal. : 2 Im/-bri-cate < L. imbricatus, overlapping like roof-tiles. 3 Val’-vate < L. valve, folding doors. 4 Ws!'-ti-va-tion < L. estivus, of the summer. 5 Ver’-na-tion < L. vernus, of the spring. 6 To/-rus < L. torus, a swelling, as being the swollen end of the floral axis. 350 THE CROWFOOT FAMILY of marsh-marigold are inserted upon the torus below the ovaries, or that their insertion is hypogynous.1 This implies that the gyncecium is inserted wholly above the other organs of the flower, or, in a word, that the ovaries are superior. Superior ovaries are found in nearly all of the crowfoot family. The torus is usually either convex (Fig. 290), conical (Fig. 293), or much elongated (Fig. 285). Peonies, on the contrary (Fig. 282), have the torus slightly concave so that it forms a shallow cup at the bottom of which the pistils are inserted, while around its rim are borne the stamens, petals, and sepals. Such insertion of the andracium and floral envelopes makes them perigynous? and the ovaries half- inferior. Wholly inferior ovaries occur as we shall see in other families but not in this. Throughout the family the floral organs are free, that is to say each set is inserted on the torus independently and develops unconnected with other sects. Furthermore, with few exceptions, the organs of each set are distinct, that is, unconnected with one another. The chief exceptions are in certain species related to the Christmas rose and in fennel- flowers where, as we have seen, the carpels have grown up joined together or are somewhat coalescent® as botanists say when the parts united are of the same sort. Another feature exhibited in general by the flowers of this family is the alternation of the parts, by which we mean that the members of one whorl or rosette stand in front of the spaces between the members of the next whorl or rosette, when of the same number. This is well shown in the floral diagrams, Figs. 178, 282, 284, 286, 287, 288, 290, 293. At first sight, this may not seem to be true of the stamens and stami- nodes of columbines and monkshoods but the alternation will be apparent when it is remembered that the parts are in whorls of five. The fruit of a flowering plant is understood to include the seeds and whatever parts ripen with them. The ripened ' Hy-pog’y-nous < Gr. hypo, beneath; gyne, pistil. * Pe-rig’-y-nous < Gr. peri, around. * Co-al-es’-cent << co, together; alescere, to grow up. THE REPRODUCTIVE SYSTEM 351 ovary is the pericarp! which may be dry as in marsh-marigold and nearly all the other genera, or may be fleshy as in bane- berries. When the pericarp opens to release the seeds it is said to be dehiscent,? and the manner of opening, its dehis- cence. The pericarp of marsh-marigold dehisces by a vertical slit, or suture * along the ventral or inner side, 7. ¢., the side toward the axis of the flower. A dry fruit consisting of one carpel dehiscing by the ventral or by the dorsal suture alone is called a follicle.: For other examples see Figs. 282, 287. A dry pericarp consisting of two or more carpels is termed a capsule.6 The fruit of fennel-flowers (Fig. 286) is a capsule in which each carpel dehisces by a short ventral suture near the top. A further peculiarity of the pericarp of the species illustrated is that except where the carpels are united, the wall separates into an outside and an inside layer, leaving a considerable empty space between. Pericarps which do not open are said to be indehiscent. A small, dry, indehiscent fruit, like that of crowfoots, anemonies, and mouse-tails is termed an achene.s A fruit like that of baneberries in which the whole pericarp is fleshy, is a berry. In a seed, as we have seen (page 316), there is an outer pro- tective layer, the seed-coat, enclosing the embryo and the seed-food or albumen. In marsh-marigold (Fig. 185) the seed-coat is of unequal thickness, the embryo minute and situated near one end of a comparatively large amount of albumen. Seeds essentially similar are found in the other members of the family. In every part of the marsh-marigold, as we have seen (page 208), there is a colorless juice which is of sharp taste and poisonous properties if eaten fresh and raw. Such an acrid, watery juice containing a more or less poisonous, usually volatile, principle, is generally present throughout the family. Crowfoots, anemonies, and monkshoods, will be remem- 1 Per’-i-carp < Gr. peri, around; karpos, fruit. 2 De-his’-cent < L. dehiscere, yawn. 3Su’-ture < L. sutura, a seam. 4 Fol’-li-cle < folliculus, dim. of follis, a wind bag. 5 Cap’-sule < L. capsula, dim. of capsa, a box. 6 A-chene’ < Gr. a, not; chainein, yawn. 352 THE CROWFOOT FAMILY bered as affording other examples already discussed in Chapter V. 104. Plant formulas. We may be helped in summing up what we have learned from our various examples if we express their most significant structural characteristics by means of symbols arranged in a sort of tabular view as on page 353. At the beginning of the formulas there given, the signs @, 2, P , +5 ,> are used respectively for annuals, perennial herbs, woody plants, small shrubs, and vines, as already explained (p. 333). A comma indi- cates an alternative, and-is to be read ‘“or.”” Thus in the formula of Pzonia we have 2,-5, reading ‘‘perennial herbs or low shrubs.” These signs since they apply to the plants as a whole come first in the formula. The letters which follow stand for various parts: L for leaves; L, leaflets; I, inflorescence; i, secondary inflorescence; B, bracts; b, bractlets; 8, sepals; P, petals; FA, stamens (filaments with anthers) ; F, staminodes (filaments without anthers) ; CE, carpels (carpellary leaves with ovules, 7. ¢., egg-sac members); E, ovules well developed; e, rudimentary ovules; T, torus; C, carpels ripened into pericarps; £7, seeds; G, embryo (germ); V, albumen (nutriment). When the leaves are alternate, as in all the genera except Clematis, this is expressed by L1/; which signifies that there is a single leaf at each internode. In the exception noted L2/s means that the leaves are opposite, 7. e., two at a node. Palmate nervation is shown by the asterisk *, ternate by the dagger sign +, and pinnate by the double dagger t, which, as will be noticed, suggest by their form the arrangement of nerves they each represent. That a leaf is com- pound is implied by the presence of leaflets indicated by the small L. In the formulas of Anemone and Clematis this shows that the leaves are but once-compound, while in the Ponia formula L!-* means that the leaves are once to thrice-compound, while L?* in the Aquilegia and Actzea formulas stands for decompound. When the inflorescence is of the indeterminate type an inverted comma follows the I as in the Aconitum and Acteea formulas; and when of the determinate type, as in the other examples, an inverted period is used. A solitary terminal flower, as in P:eonia and Nigella, is indicated by I'l. Where, as in Caltha, Anemone, and Clematis, additional flowers may appear forming a cymose cluster, [1 + is used. When the plant has only solitary axillary flowers like Myo- surus the expression becomes I'l. A cymose corymh, as of Aquilegia, is represented by I’’/; while a raceme of the botryose type, as in Aconitum and Actiea, has I’, the short and the long oblique lines standing respectively for short and long pedicels. The presence of a small i, as in the formula of Clematis, implies a compound cluster. In this case it is shown to be of paniculate form because of the relatively short pedicels. Where the type and form of inflorescence varies as in Ranunculus, their special signs may be omitted. The Peonias 4, L'/y? LP big | bis Sv 5+ P’ 5+ | FAo CE5+# ES To Ci oo Eo G-N a Bee es ee es Caltha 2 L My 5 bl, 9 [T1+é8 Ss’ 4+ FAo CE5= ha TA | Ci<6= Ho G-N Helleborus 9 L'/,*,L bis | T1l+s8 S75 F5+ | S FA CE5+,) ES Ta | = | Gre pees) Eo G-N Anemone L1/;*?,u B,b/2,3 — See eee T1+8 $’4+ FO0-« | FAo CEo Ei e4+ Ta Nigella @ L Wt L b/s, Ci means that the torus is convex and implies that the perianth and andrcecium are hypogynous. When as in Peonia they are perigynous this is indi- cated by T u which represents the torus as concave. The form of the ovules is shown by a mark placed over their numerical sign, a circumflex accent-mark meaning that the ovule is anatropous. Their ventral position is understood in simple pistils, while in compound pistils like that of Nigella, the single parenthesis after the number of carpels implies that the ovules are on an axile placenta. When the pericarp becomes fleshy as in Acta this is indicated by an exclamation mark after the C. When the pericarp is dry, as in Caltha, there is instead an inverted exclamation mark. Inde- hiscence is indicated by the sign <. When the pericarp dehisces along a ventral suture as in Caltha, etc., the sign < is employed. In all the formulas the expression G-N implies that the embryo is uncoiled within albumen. The scheme of plant. formulas which is here proposed and which will be further elaborated in the following pages, is an extension and modification of the floral formulas used by many botanists. As a sort of botanical shorthand of wide application it is believed that the student will find it not only labor-saving but helpful in grasping plant relationships. After a little use, what seemed strange will have become familiar and a glance will discover important characters that might easily escape notice in comparing equally full verbal descriptions. 105. The family chain. Having learned the signification of these symbols we are now in position to use the formulas as a ready means of comparing the main structural features of our representa- tive genera to see how they are linked together. Take, for instance, Caltha and Peonia. If we conceive of a marsh-marigold having a concave torus, a perianth differentiated into calyx and corolla, and pinnately compound leaves, such a plant would be classed as a peony. By these same features, however, it might be distinguished from all the other genera. Therefore, although closely linked with Caltha, Pzeonia is placed on a line apart in the tabular view. Helleborus differs from Caltha chiefly in having the carpels some- times coalesced and in possessing staminodes. In these respects it is a link connecting Caltha with Nigella which has the carpels always coalescent, and differs from Helleborus only in having pinnate instead of palmate leaves, some of which may be so near the flower as to constitute an involucre, and in consisting of annual rather than perennial herbs. Aquilegia, with its carpels distinct, is more like Caltha, but differs from both Caltha and Nigella in having the carpels always five, staminodes in two inner sets of five and one outer set of the same number, and in having the leaves ternately decompound. 356 THE CROWFOOT FAMILY A monkshood is like a columbine except for irregularity of sepals and staminodes, absence of inner staminodes, indeterminate inflorescence, simplicity of leaves, and sometimes fewer carpels. All the above genera agree in having numerous ovules, all of which may become seeds, contained in several or many carpels which become dry and dehiscent in fruit. In Actwa the carpels are reduced to one, which becomes fleshy and indehiscent in fruit; the staminodes may be fewer, both they and the sepals are regular; and the leaves are ternately decompound: otherwise the genus resembles Aconitum. Passing now to Anemone we find its most striking differences from Caltha and the other genera already described to be the im- perfect development of several of the ovules im each carpel, the ripening of only one ovule, the indehiscence of the fruit, and the possession of an involucre of two or three bracts. In these respects it forms a link between our type genus and Clematis where the rudimentary ovules are commonly fewer, and all the leaves (like the bracts in some species of Anemone) are opposite. A still further divergence in Clematis appears in the occasional imperfection of the flowers, the valvate wstivation of the sepals, the ternate or pinnate nervation of the leaves, and the climbing habit and woody stem sometimes developed. In Ranunculus we find a still further reduction of the ovules; an invariable presence of both essential organs and staminodes; imbricate zstivation of the sepals: alternate, palmate, simple leaves; and sometimes annual duration: thus being in some respects more nearly like Caltha, while in others it is more divergent. Finally, an extreme of divergence by reduction or simplification is reached in the mouse-tails which may be regarded as annual crow- foots with only about five stamens, staminodes, and sepals, bractless, solitary flowers, and leaves with unbranched or obscure nervation. It may seem a long way from such plants to peonies; but, as we see, there are intermediate links binding them pretty closely together. As the student examines other members of the same family he will find that they may be readily interposed as links in the same chain with those already studied. Indeed, the transitions will appear less abrupt than between the few examples to which we have confined ourselves. His experience will be much like that of a botanist er forms newly discovered. He compares them with the forms already known and links them with those which they most nearly resemble. Thus link by link are family chains forged in botanical systems. As in the present, case, the chain may branch, and it might be questioned whether it would not be better to regard the branches as separate families. That depends upon how close the linkage appears to be, and as to that the judgment of experts may differ. In any event the definition of any family properly follows the attempt at natural grouping, and may require revision with advancing knowledge or change of view. Such changes in THE FAMILY CHAIN 357 classification the history of the science illustrates; yet progress is in the direction of stability, and certain chains, having held from the first, bid fair to endure. The integrity of the Ranunculacex, for example, seems assured in spite of the wide divergence of its extreme forms and in spite of the difficulty of defining its limits. We have now to define the family as best we can. The generic formulas will help us to a formula for the family and this in turn will lead us to our definition. Taking the prevailing characteristics of each part as typical for the family, and neglecting the less sig- nificant exceptions to the general rule, we may express a generalized view of the salient features as shown in the formula of Ranunculacewe on pages 404, 405. The only invariable features here expressed are the anatropous ovule and the uncoiled embryo surrounded by albumen, and these as we shall see are common to a number of other families. But, as we shall also see in comparing the Ranunculacez with other groups, it lacks features which they possess. Taking into account all the facts we have learned, the crowfoot family may be described as consisting of herbaceous or rarely woody plants, never trees, without milky juice, oil or other secretions in special reservoirs, but with a mostly colorless and odorless sap which is generally acrid, and in some cases renders the plant poisonous to eat or to touch; leaves mostly palmately branched, or at least palmately ribbed; flowers mostly regular and perfect with the parts free and distinct (with rare exceptions); sepals commonly five, generally petaloid; petals rarely present, often replaced by more or less petaloid staminodal nectaries of widely differing forms; stamens generally numerous; anthers de- hiscing by slits; pistils almost always simple, numerous, few, or rarely solitary; ovules anatropous, many, few or solitary, sometimes rudimentary; fruit follicular, capsular, achenial, or rarely fleshy; the seeds with hard albumen sur- rounding a minute uncoiled embryo. Or, if we disregard all that is untypical, it may be said that whenever we find an herb with the juice colorless and scentless, the flowers having all their parts distinct and free, sepals about five, and essential organs numerous, we may be tolerably sure that our plant is one of the crowfoot family, although some departure from these characteristics would not necessarily exclude it from the group. CHAPTER X VARIOUS PLANT GROUPS 106. The magnolia family (Magnoliacez) is a compara- tively small group well represented by magnolias (Mag- nolia, page 262), the tulip-tree (Liriodendron, page 261), and star-anise (Illicium, page 143). At first sight there might seem to be small resemblance between these and crowfoot- like plants; but let us see upon what points of difference we ean exclude them from the crowfoot family. The seeds are essentially the same as those of the crowfoot family in having a small uncoiled embryo in copious albumen. The fruit of star-anise consists of follicles, much like those of the marsh-marigold, though with only one seed in each; while the carpels of the tulip-tree ripen into achenes differing from those of anemonies mainly in having wing-like out- growths. Such winged fruits are termed samaras.! The mag- nolia fruit consists of a cone-like aggregation of follicles differing from those of star-anise in dehiscing by a dorsal suture, and in producing one or two seeds which have a fleshy outer layer of bright color, and which dangle on slender threads when ripe. Neither the andreecium nor the perianth present any new features. Nor do we find anything essen- tially different in regard to the inflorescence or the leaves except that in the tulip-tree and magnolia there are leaflet- like appendages at the base of the petiole. These stipules,? as they are called, serve as organs of protection for the unex- panded leaves. In these plants they soon fall off, and so do not appear in the figures. Well-developed stipules are shown 1Sa-ma’ra < L. samara, the winged fruit of the elm. *Stip’ule < L. slipula, stubble, diminutive of stipes, stalk, the stipules in their relation to the petiole being likened to the short stubble standing at the base of a stalk of grain. 358 THE MAGNOLIA FAMILY 309 in figures 159,2 and 271. Somewhat similar expansions serv- ing for protection occur at the base of marsh-marigold leaves; but these, although suggesting stipules, are not regarded as sufficiently developed to deserve the name. The leaves of star-anise, as of the crowfoot family, are exstipulate,! that is, without stipules. Finally, asregards their habit,? or general ap- pearance, the tulip-tree is, as itsname implies, a tree, while the species of magnolia and star-anise are either trees or shrubs. The result of our examination thus far is to show that star-anise in several particulars forms a good link connecting the tulip-tree with members of the crowfoot family, and we have not yet found a single feature which will serve to dis- tinguish all of the magnolia family from all of the crowfoot family. This resemblance will appear still more plainly if we express in formulas the facts observable in our examples. Let us indicate the presence of stipules by an inverted dagger sign, 1; a wing on the pericarp by an inverted interrogation mark, ¢; and dorsal dehiscence by >. We may then write our formulas of Magnolia, Illicium, and Liriodendron * as shown on pages 404, 405. If we added to these examples other magnoliaceous genera we should of course introduce some new variations of structure, but these would afford us no better family characters. A formula typical of the family would still be the same as that given below the three genera mentioned. Comparing our magnoliaceous formulas with the ranunculaceous ones we find that while prevailing features differ—so much so indeed as to make it desirable to group the plants in separate fam- ilies—the departures from the type in one family often match those of the other. There is, however, a general difference, not shown in the figures, which serves to separate the two groups. All mem- bers of the magnolia family have in the leaf-pulp, floral leaves, pith, and other soft parts, minute reservoirs of volatile oil, which are entirely lacking in the crowfoot family. These little reservoirs may be seen readily with a hand lens by viewing 1 Ex-stip’u-late < L. ex, without; stipula, stipule. 2 Habit < L. habitus, appearance. 3The plant formulas referred to in this and succeeding sections, together with the ranunculaceous formulas already given, are grouped on pages 404-427 to facilitate their being compared with one another. 360 VARIOUS PLANT GROUPS a leaf, petal, or slice of pith against the light, when they ap- pear as translucent, scattered dots. This oil it is which renders the flowers of the family fragrant, and gives its flavor to the fruit of star-anise. Searcely a trace of such odors are to be found in the crowfoot family. We may therefore define the magnolia family as woody plants having fragrant, solitary, regular flowers, more or less like those of the crowfoot family, but with minute reservoirs of volatile oil in varvous parts. 107. The laurel family (Lauracez) consists also of woody plants with oil reservoirs similar to those of the magnolia family. This aromatic oil gives to sassafras (Sassafras officinale, page 168) and to cinnamon and camphor (Cinna- momum, pages 135, 178), as we have seen, their chief economic value. Between these and our examples of the magnolia and crowfoot families may also be found many other similarities, either in habit, form of leaves, or floral structure. The morphology of the gyneecium in the laurel family is somewhat doubtful. Apparently there is only a single carpel, much as in the baneberry, but in sassafras the three-lobed stigma may be evidence of three carpels which coalesce so completely as to form a one-celled, one-styled pisfil. A further peculiarity of sassafras is that the flowers are all imperfect and that the two kinds are always on distinct plants. The term diecious ' is applied to this condition. A striking feature found throughout the family is the dehiscence of the anthers by uplifted valves. This is indicated in the formulas by FA. Another general peculiarity is that the concave torus often becomes fleshy and cup-like in fruit—a condition indicated by TUT!. The sign © meaning “or otherwise”? when there are noteworthy exceptions, is also introduced inthe formulas of this family, and ? is used to indicate doubt. See pages 406, 407 for formulas of Sassafras and Cinnamomum and, derived from them (neglecting exceptions) a typical formula for the family. Woody plants with minute reservoirs of oil, and regular flowers more or less like those of the crowfoot family but having the perianth and andracium mostly perigynous and the anthers ' Di-ce’ci-ous < Gr. dis, two; ofkos, houschold; symbolized by @: @. THE POPPY FAMILY 361 always dehiscing by uplifted valves, constitute the chief mem- bers of the family. : 108. The crowfoot order (Ranunculales or Ranales). A comparison of the three families we have been studying shows them to be closely linked together, much as are the genera within each family. By such linkage there is formed a natural chain of families including these and several others resembling them in important respects. Such a group of families is termed, as we have seen (page 8), an order. That which clusters about the crowfoot family takes significantly the name of the crowfoot order. The prevailing characters of Ranunculales are expressed in the formula of the order given on pages 406, 407. Neglecting the more variable or exceptional features we may say that the plants of this order, though differing widely in habit, foliage, and inflorescence, are characterized by having usually cymose inflorescences of mostly perfect, regular, and hypogynous flowers with well-developed perianth often in whorls of three, stamens and carpels usually numerous, and all parts commonly distinct and free. 109. The poppy family (Papaveracez) is represented sufficiently well for our purpose by the opium poppy (Papaver somniferum, pages 182,183). Like all the other species of its genus, it contains instead of volatile oil a milky juice from which, as we have seen, opium is obtained. Many other genera of the family contain a similar juice which in some cases is bright yellow, and in others red. Sometimes the juice 1s watery. The main structural features of Papaver appear in its formula on pages 406, 407. The only new features calling for special notice concern the gyncecium which, unlike any in the crowfoot order (ex- cept possibly in the laurel family), consists of several carpels so united as to form a compound pistil with a one-celled ovary. That is to say, the carpellary leaves as they grow have the right edge of one coalescent with the left edge of its neighbor. The united edges of neighboring carpels thus form placentze which lie along the outer wall of the compound 362 VARIOUS PLANT GROUPS ovary. Such placent# are termed parietal.1| The capsule in poppies opens peculiarly by little pores like windows under the eaves of the overhanging stigma-ring. Such opening by pores, is called poricidal ? dehiscence. With but slight modifications, not calling for special comment, the formula of Papaver becomes typical of the family as shown on pages 406, 407. The family may generally be recognized as being mostly herbs, commonly having a milky or colored juice, and hypogy- nous flowers with the floral envelopes most often in whorls of two, the stamens usually numerous, the pistil always compound, one-celled and with parietal placente, and the seeds albuminous with the embryo sometimes curved but neither coiled nor bent. 110. The mustard family (Cruciferz) agrees closely with the poppy family in general form and floral structure, as may be seen by comparing our figures of cabbages, turnips, mustards, and rape (Brassica, pages 54, 66-70), watercress and horseradish (Nasturtium, pages 70, 71, 144), and radish (Raphanus, page 55). The main family differences are in the bracts and bractlets, the number of stamens, and peculiarities of the gynoecium. While the members of the poppy family have bracts and often bractlets of the usual sort (which therefore do not call for special notice), the members of the mustard family are almost unique in having no bracts within the inflorescence. Hence they are described as ebracteate.* In a flower of the mustard family there are two outer and shorter stamens, alternating with two inner pairs of longer ones. Botanists regard these inner pairs as representing each a single stamen branched or divided into two. The fact that a whorl is thus divided into sets is expressed in our formulas by the sign of division, +, connecting the number in the whorl with the number of sets. The carpels of the mustard family are normally only two, 1 Pa-ri’e-tal < L. parictalis, belonging to a wall <_ paries, a wall; indicated by the symbol () placed after the number of the carpels. * Por-i-ci’dal < L. porus, pore; cadire, to cut; indicated by the sign® placed after that of the pericarp. 3 E-brac’te-ate < L. e, without; bractea, bract. Bo. THE ROSE FAMILY 363 as in certain of the poppy family, but the ovary instead of being one-celled is divided into two compartments by a partition extending between the parietal placentee. When ripe the carpels mostly separate from the placente and from this partition. Such a fruit is called a silique.1 The ovules differ from any we have seen among the plants of the crow- foot order in lacking a raphe and being curved to a somewhat kidney-like form. When thus curved, ovules are described as campylotropous.? The seeds are almost always exalbuminous and have the embryo commonly bent in various ways—a peculiarity expressed in the formulas by GA. Note how closely similar are the formulas of Brassica, Nasturtium, Raphanus, and Crucifere given on pages 406, 407. As a definition of the family we have thus:— Mustard family: mostly herbs without milky or colored juice or oil reservoirs, often of sharp taste though pleasant flavor; ebracteate inflorescence; usually hypogynous flowers with all the parts in whorls of two (with the apparent exception of the four inner and longer stamens), the ovary divided into two cells by a partition joining the parietal placenta; the fruit almost always a silique with exalbuminous seeds having the embryo variously bent. 111. The poppy order (Papaverales or Rhceadales) com- prises a few families well represented by the poppy and the mustard families and agreeing in having mostly racemose inflorescences of complete, hypogynous, regular or irregular flowers with the sepals, petals, and stamens all distinct and free, and a compound pistil with parietal placente. It is the union of the carpels by their edges which mainly dis- tinguishes this from the crowfoot order. For comparison we have a typical formula of the order on pages 408, 409. 112. The rose family (Rosacez) as illustrated by the almond (Fig. 31, page 42), apple (Figs. 91 I, II, pages 86, 87), pear (Fig. 92, page 87), quince (Figs. 93 I, II, page 88), 1 Gi-lique’ < L. siliqua, a pod; Cj*. 2 Cam-py-lot’ro-pous < Gr. kampylos, curved; trope, a turn. E @. é 364 VARIOUS PLANT GROUPS peach (Fig. 94, page 89), plum (Fig. 95, page 90), cherry (Fig. 96, page 90), raspberry (Fig. 97, page 91), straw- berry (Figs. 98 I-III, page 92), and roses (Figs. 148 II, III, 298, pages 150, 151, 378), 1s seen to possess many features of floral structure resembling more nearly those of the crowfoot family than of any other family we have studied. Note in the formulas of Rosa, Fragaria, Rubus, Prunus, Cydonia, and Pyrus, given on pages 408, 409, that the floral envelopes are mostly in fives, while the essential organs are commonly numerous, and that all are free and distinet, except sometimes the carpels, which then, unlike poppy carpels, have axile placente. An unusual form of calyx is found in strawberries (Fra- garia). Here the sepals have stipules which coalesce in pairs so as to form what looks like a calyx upon a calyx, and is termed therefore an epicalyx.' The only other features not before encountered belong to the torus and the fruit. Throughout the family the torus is concave or cup-like, and it is mostly free as in peonies and our examples of the laurel family. In roses (Rosa) it completely envelopes the carpels, and be- comes fleshy and bright colored while the pericarps ripen into hard nutlets,? the whole forming a so-called “‘hip.’”’? The strawberry fruit consists mainly of the upper part of the torus,’ much swollen and bearing numerous achenes. Rasp- berries have the upper part of the torus comparatively dry, and in fruit the pericarps finally separate from it. As these ripen, an outer layer becomes fleshy while an inner layer hardens like an olive stone. A fruit in which the pericarp is thus differentiated is called a ‘‘stone-fruit’”’ or drupe. In raspberries and thimbleberries the little drupes coalesce sufficiently to form a thimble-lhke mass after they separate from the torus. In blackberries, on the contrary, the little drupes remain attached to the part of the torus which bears 1B"pi-ca/lyx < L. epi, upon. § | 2 The hardening of the pericarp is expressed in the formulas by two inverted exclamation marks. * A smalléto represent part of the torus is used in the formulas instead of the large capital. ‘Drupe < L. drupa, a ripe olive. Cjj! THE PULSE FAMILY 365 them, or in other words, the pericarps adhere ' to the torus, as botanists say of the union of dissimilar parts. Such adhesion is represented in the Rubus formula by a bracket placed after the pericarp signs. The bracket is separated by a comma from the preceding signs to show that in this genus the pericarps are sometimes free. Similarly the expression ¢j,/, means that the upper part of the torus may be either dry or fleshy in fruit, while C7j! means that each pericarp is hard within and fleshy with- out, v. €., drupaccous. Each flower of plums, peaches, almonds, and cherries (Prunus) produces but a single drupe, and this has commonly but one seed within the “stone”; though occasionally as in “philopena” almonds both of the ovules develop. It should be noted that neither the ‘‘stone”’ of a peach, plum, or cherry nor the “shell” of an almond is part of a seed, but is the hardened inner layer of the pericarp, enclosing a seed or seeds. The torus of quince (Cydonia) and of apples and pears (Pyrus), envelops the gyncecium, is adherent to the com- pound ovary, and both ripen together into the kind of fruit called a pome ? in which the seeds are enclosed in a “core” consisting of dry, more or less parchment-like pericarps, surrounded by the fleshy torus. An adherent torus envelop- ing the ovary is said to be epigynous,* a term likewise applied to the stamens, or the floral envelopes which it bears; and, indeed, to the flower itself having such a torus. The ovaries of epigynous flowers are termed inferior. A typical formula for the family is shown on pages 408, 409. The family includes plants of various habit; without milky, colored, or acrid juice, and lacking reservoirs of volatile oil; but having often fragrant flowers more or less like those of the crowfoot family, but perigynous or epigynous; mostly stipulate leaves, and frequently luscious fruit. 113. The pulse family (Leguminosz). Examples: pea- nut (Fig. 33, page 45), pea (Figs. 37, 38, page 48), beans 1 Ad-here’ < L. ad, to; herere, stick. | F 2 Pome < L. pomum, an apple or similar fruit. PEG 3 Ep-ig’y-nous < Gr. epi, upon; gyne, pistil. TL] 366 VARIOUS PLANT GROUPS (Figs. 39, 40, pages 49-51), gum arabic tree (Fig. 156, page 164), tragacanth shrub (Fig. 157, page 165), licorice (Fig. 162, page 169), locust (Fig. 182, page 197), courbdril- tree and Zanzibar copal-tree (Fig. 273, page 289), indigo shrub (Fig. 275, page 293), and logwood-tree (Fig. 276, page 294). See on pages 408-411 the formulas given for Acacia, Heematoxy- lon, Hymenea, Trachylobium, Pisum, Phaseolus, Robinia, Indigo- fera, Glycyrrhiza, Astragalus, Arachis, and Leguminose. In their floral structure many acacias, like the gum arabic tree, approximate closely to certain members of the rose family, notably in the numerous stamens, and regular calyx and corolla. In some species the filaments are more or less coalescent. Stamens thus united are said to be monadel- phous.! The logwood-tree (Hematoxylon), the courbaril- tree (Hymenza) and the Zanzibar copal-tree (Trachylobium) present irregular corollas, with the peculiarity that the uppermost petal is at first enfolded by the side ones, and these in turn by the lower pair. A large majority of the family, represented by peas (Pisum), beans (Phaseolus), and the other examples referred to, have what is called a papil- ionaceous ? corolla. This consists of five petals: one com- paratively large called the standard, which is above the others and enfolds them in the bud; two side ones called the wings; and two lower ones grown together to form what is called the keel. A curious condition of the andraecium commonly found with the papilionaceous corolla is that there is one uppermost stamen free from the other nine which are more or less coalescent. Such an androecium is termed diadelphous.* Another peculiarity usually accompanying the papilionaceous corolla is the irregularity and coalescence of the sepals to form a calyx described as gamosepalous 4 and bilabiate,® that 'Mon’a-del’phous < Gr. monos, one; adelphos, a brother; meaning in one brotherhood; indicated by the small parenthesis. * Pa-pil’i-on-a’ccous < L. papilio, a butterfly—from the resem- blance. This is expressed in the formula by P’’s!3). * Di'’a-del’phous < Gr. dis, two; FA}. 4Gam"o-sep’al-ous < Gr. gamos, union; S). > Bi-la’bi-ate < L. bis, two; labium, lip; S*). THE LINDEN FAMILY 367 is to say, consisting of sepals more or less united, so as to form an upper and a lower lip. The most distinctive peculiarity of the family is its typical fruit, called a legume.: This consists of a single carpel which becomes dry and normally splits into two valves by dorsal and ventral sutures. Asin the mustard family we found that the radish has an indehiscent pod of two carpels which is essentially a silique in structure, so here in certain genera we find pods of one carpel, essentially legumes, but without the usual mode of dehiscence. Peanuts, for example, though indehiscent, are plainly like pea-pods in most important re- spects, and both may well be called legumes. A still stranger modification of legume is the fruit of Hematoxylon which dehisces into two valves but along lines midway between the ventral and the dorsal sutures, as indicated by Cj <>. The great majority of our wild or cultivated members of the pulse family may be recognized by their having mostly papilionaceous, or at least irregular corollas, and a single carpel which forms a legume, while in other respects these plants are similar to those of the rose family. 114. The rose order (Rosales) includes several families which agree for the most part with the rose and the pulse family in bearing botryose inflorescences of usually complete © perigynous flowers, regular or irregular, having petals at least partly distinct, and pistils with a ventral or axile placenta. These features are indicated in the formula of Rosales on pages 410, 411. 115. The linden family (Tiliacee#.) Examples: jute (Figs. 218 I, II, page 232), and linden (Figs. 251, 252, page 264). See the formulas of Corchorus, Tilia, and Tiliacez on pages 410, 411. The bracts of lindens (Tilia) and the andreecium and fruit of the family present the chief peculiarities which call for present notice. The bracts of jute (Corchorus) present 1 Leg’ume < L. legumen, beans, etc., or that which may be gathered by hand without cutting < legere, gather. Its sign is Cj. 368 VARIOUS PLANT GROUPS no special peculiarities. In lindens, however, the lowermost bract of the flower-cluster is large, forming a sort of involucre, and adheres for a considerable distance to the peduncle. Jute flowers, which have the stamens in two whorls of five each, thus conforming to the numerical plan of the other floral organs, afford the simplest condition. In other species the stamens appear to be indefinite in number, but close examination would show them to be grouped into five clus- ters opposite the five petals. Each cluster is taken to repre- sent the branches of a single one of the inner whorl of stamens, in much the same way that a pair of long stamens in the mustard family represent, as we have seen (section 110), a single branched stamen. The fact that the stamen-groups are opposite the petals (hence regarded as being of the inner stamen whorl) is expressed by placing the sign || between P and FA. Stamens in five clusters are said to be pentadelphous.: The stamens of the linden are always pentadelphous, and sometimes each cluster includes a staminode to which the anther-bearing filaments are coalescent. Throughout the family two pollen-sacs are borne by each filament which, however, divides more or less at the tip into a short stalk for each sac. The fruit of jute is a capsule dehiscing by dorsal sutures into valves attached to the radial partitions. Such dehiscence is called loculiecdal.2 In lindens only one of the five carpels ripens, and commonly only one of the seeds which it contains. The pericarp becomes somewhat drupaceous so that the product of each flower resembles a small round almond. But a cluster of these nut-like fruitlets is formed by each in- florescence, and this cluster, borne on a common peduncle to which the bract still adheres, separates at maturity as a whole from the tree. The dry bract serves excellently as a 1 Pen’’-ta-del’phous < Gr. pente, five. FA o + 5. * Loe’u-li-ei“dal << L. loculus, a compartment; cedere, cut, because it is as if each compartment were cut into, so that in eross-section each division has a form something like the sign {|- which is used to distin- guish this (ype of capsule in the formula of Corchorus. THE MALLOW FAMILY 369 sail to carry the fruit-cluster before the wind over smooth ground or a crust of snow. The family comprises mostly woody plants having mucilag- inous juices; and often fragrant flowers with petals imbricate and distinct; stamens numerous, pentadelphous, and free; anthers with two pollen-sacs; and styles coalesced throughout. 116. The mallow family (Malvacez). Examples: cotton (Figs. 214-216, pages 225-227) and marshmallow (Fig. 158, page 166). See pages 410,411 for formulas of Gossypium, Althea, and Malvacee. Several new features are presented in this family. An involucel is commonly present close to the flower, recalling the epicalyx of strawberries, but here we have bractlets in place of stipules. The sstivation of the corolla is such that one edge of each petal overlaps its neighbor, while the other edge is in turn overlapped by the next in order. Afstivation of this type is termed convolute.. The andrcecium appears to consist of a number of stamens borne upon a long tube enclosing the styles. This tube shows at the top, more or less distinctly, five projections which give evidence that the andreecium consists really of but five stamens coalesced by their filaments to form the tube, and branched above into the numerous stalks bearing pollen-sacs. Curiously enough each branch bears only a single pollen-sac and is thus equiva- lent to but half of an ordinary anther. The expression FA o-+5)] would read “stamens numerous, divided into five groups, monadelphous, and adhering to the petals.” As a result of this adhesion the petals, although distinct, fall off in connection with the stamen-tube (as the fruit ripens) much as if they were coalescent. The fruit of marshmallow (Althea) represents a type very common in the family. Although indehiscent, the basal part of the several carpels, as they ripen, separate into as many nutlets, each containing a single seed. The fruit thus returns to a condition very like that of a cluster of anemone 1Con’vo-lute < L. con, together; volvere, roll. P*‘ is the sign. 370 VARIOUS PLANT GROUPS achenes. A fruit thus splitting into one-seeded pieces is called a schizocarp.' The family comprises mostly herbaceous plants rich in muct- lage; with flowers often involucellate, seldom fragrant; petals convolute and distinct; stamens numerous, monadelphous, adhering to the corolla; anthers with only one pollen-sac; styles more or less distinct. 117. The mallow order (Malvales) contains several families having mostly cymose inflorescences of complete, regular, and hypogynous flowers; with the petals distinct (though often ad- hering to the pentadelphous or monadelphous stamens) and opposite the stamen-groups; and the pistils with axile placente. See pages 410, 411 for a typical formula of the order. 118. The parsley family (Umbellifere). Examples: car- rot (Figs. 47-53, pages 55-57), parsnip (Figs. 54, 55, page 57), celery (Figs. 78, 79, page 75), parsley (Fig. 1388, page 140), caraway (Fig. 140, page 142), anise (Figs. 141 I, II, page 142), coriander (Figs. 143 I-III, pages 1438, 144), asafetida (Fig. 168 I, page 175), water hemlock (Fig. 179, page 193), and poison hemlock (Figs. 180 I, II, pages 194, 195). See pages 410-413 for formulas of Conium, Carum, Petroselinum, Cicuta, Coriandrum, Apium, Pimpernella, Pastinaca, Ferula, Daucus, and Umbelliferee. The name Umbellifere, meaning “umbrella-bearers,” was given to this family because almost all the members have inflorescences resembling umbrellas. This form of in- florescence, called an wmbel,? may be likened to a raceme in which the internodes of the rachis are suppressed, thus bring- ing the bracts, when present, together as an involucre. In most of the parsley family, the inflorescence consists of a number of little umbels or wmnbellules,? arranged in an umbel. Usually all the flowers of a cluster are perfect. An interest- 1Schiz’o-carp < Gr. schizo, I split; karpos, fruit. Cj <—+o. 2Um’‘bel < L. wmbella, diminutive of wmbra, shade. I/. 4Um'bel-lule < L. wmbellula, diminutive of wmbella. i/. Each um- bellule may have a secondary involucre composed of secondary bracts which are symbolized by the B? which comes after the B. : THE PARSLEY ORDER 371 ing exception is found in the carrot (Daucus) where there is often a central flower destitute of essential organs. Such a flower is described as neutral. The sepals are commonly reduced to small tooth-like projections, or they may be so united into a narrow ring as to appear obliterated. The calyx-teeth do not touch in the bud; hence their estivation is said to be open.2. More or less irregularity of calyx and corolla occurs among the outer flowers of an umbel, though most of the flowers are but little if at all irregular. The two-carpelled, inferior ovary ripens into a dry fruit which at maturity splits in halves, each half hanging from the top of a continuation of the torus, as shown in Fig. 141 IT. Such a fruit is called a cremocarp.* It is like a schizocarp except that it is the product of an inferior ovary. Each half has several more or less pronounced ribs; and, in the wall, parallel to the ribs, are often tubular reservoirs of volatile oil giving a characteristic odor to the fruit. An odor similar to that of the fruit often pervades every part so that from an immature specimen or only a fragment it is often possible to recognize these plants by their peculiar, though indescribable, smell. The stems have the rare characteristic of being hollow even at the nodes. Herbs rich in volatile oil, but with watery sap; having leaves exstipulate; flowers regular or irregular, mostly in compound umbels, often involucrate; the petals and stamens five, the carpels two, styles distinct; and the fruit a cremocarp—such are the typical members of the family. 119. The parsley order (Umbellales or Umbelliflore) in- cludes two other families which agree with the parsley family in having mostly umbellate inflorescences of small, complete, epigynous flowers, with the petals and stamens distinct and alternate, and the carpels with but a single ovule in each. For the formula of Umbellalles see pages 412, 413. 1 Symbolized by the sign 6. , 2 Expressed in the formulas by 8’‘. : 3 Crem/o-carp < Gr. kremao, I hang; karpos, fruit. TC] < + 2. 372 VARIOUS PLANT GROUPS 120. The buckwheat family (Polygonacez). Examples: buckwheat (Fig. 22, page 29) and rhubarbs (Fig. 112, page 104, and Fig. 163, page 170). See pages 412, 413 for formulas of Rheum, Fagopyrum, and Poly- gonaces. The stems of plants belonging to the buckwheat family are commonly swollen at the joints, and have above each node a thin tubular sheath formed by the coalescence of the stipules. These sheaths are called ocree,! and the plants or leaves are said to be ocreate. The parts of the flower are commonly in threes although there are some curious departures from the type. Thus in buckwheat (Fagopyrum) there are five sepals as against the six-leaved perianth of rhubarb (Rheum), but we may regard the missing sepal as represented by a bractlet which is ab- sent in the other inflorescence. Again, the six outer stamens of rhubarb are to be regarded as three pairs, each pair formed from the division of one stamen into two; while in buckwheat the andreecium is similar except that one of the outer stamens has remained undivided, thus giving but eight in all. That there are three carpels is shown clearly by the three distinct styles, though there is but one cavity from the base of which arises a single ovule. This ovule differs from the others we have studied in having the micropyle opposite to the funicle, that is to say, in being straight or orthotropous.? The family consists mostly of herbs with a watery juice which is often peppery and sometimes pleasantly acid, without reservoirs of volatile oil; having stems often swollen at the joints; leaves ocreate; styles two or three, distinct; ovary containing a single, orthotropous ovule; and the fruit an achene. 121. The buckwheat order (Polygonales) which con- tains only the above family, may he contrasted with the previous orders as having mostly paniculate inflorescences of small, regular, perfect, hypogynous flowers, with the perianth, 1Oc’re-a < L. a legging. Li). > Or-thot’ro-pous < Gr. orthos, straight. Symbolized by a straight, line over the numerical sign, 121. THE BIRCH FAMILY 373 leaves, and stamens distinct and alternate, and the ovary with but one cavity and one ovule. The formula of Polygonales is given on pages 412, 413. 122. The birch family (Betulacee). Examples: filbert (Fig. 23, page 36) and birch (Fig. 254, page 265). See pages 412-415 for formulas of Betula, Corylus, and Betula- cen. We meet in this family with the singular form of inflores- cence sometimes called ‘“‘pussies,’’ or catkins, and known botanically as aments.. An amentaceous inflorescence is typically an elongated, often dangling, cluster of imperfect flowers which are in the axils of scale-like bracts. It is a special form of spicate? inflorescence, spike? being the general term for a racemose cluster of sessile or nearly sessile flowers. If the internodes of a spike fail to elongate the flowers become crowded into a head or capitate * inflorescence. In the axil of each scale of a birch catkin we find three flowers (Fig. 254) closely crowded together and so forming the simplest sort of head. These heads of staminate flowers are borne along the sides of a slender hanging rachis, so that the whole compound cluster forms a typical ament. The pistillate heads occur on a stiffer rachis which commonly grows erect, and might therefore properly be called a spike although on account of its scale-like bracts botanists often speak of this inflorescence as a pistillate ament. In the pistillate inflores- cence of hazels (Corylus) the little heads (here two-flowered) are so few and crowded as to form a compound head of heads. In the hazels the staminate flowers are solitary in the axils of the scales, thus forming simple aments; while the pistillate flowers are grouped in heads of two, and each flower is sur- rounded by an involucel formed of its special bract and its 1Am/ent < L. amentum, a thong or shoestring. Ij. 2 Spi’cate, spike < L. spica, an ear of corn. [:. 3 Cap’i-tate < L. capitatus, having a head < caput, head. I. 4 All these facts are expressed in the formulas by using an inverted exclamation point as the symbol of an amentaceous inflorescence, an inverted colon for spicate, and two inverted periods for capitate clusters. That the bractlets are adherent to the bracts by their lower parts is shown by the small bracket, 3, 374 VARIOUS PLANT GROUPS two coalescent and adherent bractlets. Plants with both staminate and pistillate inflorescences borne upon the same individual plant are termed monecious.? The united bracts and bractlets of birches (Betula) ripen into dry scales forming a cone-like cluster of fruits made up of little samaras. In hazels the involucre becomes much enlarged in fruit, and each surrounds a much hardened peri- carp which because of its hardness and indehiscence is called a nut.® The family comprises woody plants without oil reservoirs but with resinous warts or hairs on the younger parts; simple, stipulate leaves; and monecious inflorescences, the staminate amentaceous, the pistillate in spikes or heads with coalescent bracts and bractlets, and the pistils of two carpels with axile placente. 123. The beech family (Fagacee). acne chest- nut (Figs. 24-26, pages 37, 38), oaks (Figs. 242, 243, 267, pages 257, 258, 277), and beech (Fig. 257, page 268). See pages 414, 415 for the formulas of Fagus, Castanea, Quercus, and Fagacez. The inflorescences of this family resemble those of the preceding family in being moncecious and in part amenta- ceous. It is in the bracts and the way they are borne that we find the most significant differences—differences which become more striking as the fruit matures. Indeed, bot- anists have here met with a morphological problem of more than ordinary difficulty in the preliminary question: What are the homologues of bracts which ripen with a beechnut, a chestnut-bur, or an acorn? In the staminate inflorescences of beech (I’agus) and chest- nut (Castanea) the bracts are obvious enough and are sufh- ciently like those of the birch family to require no special ! Mo-nee’cious < Gr. monos, one; otkos, household. This is indi- cated by o-9. If the staminate inflorescence differs in form from the pistillate the nature of each is shown by placing the inflorescence signs in corresponding order, 7. e., beginning with the staminate. Thus lit would read “staminate inflorescence amentaceous, the pistillate spicate, both compounded of heads.”’ 2 In the formula this extra hardness of the pericarp is indicated by two inverted exclamation points. THE BEECH FAMILY 375 comment; while the staminate flowers of Quercus are ebrac- teate. The pistillate flowers of beech are two in a head (Fig. 257) which is enclosed in a little cup or cupule + as it is called, bearing scales or spines on its outer surface. This cup eventually encloses completely the ripening nuts, and when mature splits into four partial valves to set them free. The cupule of chestnuts encloses three flowers, ripens into the spiny bur, and splits sometimes into four valves, and sometimes irregularly. Only one flower is in the scaly cupule of oaks (Quercus), and the single nut which constitutes the acorn is so little covered by the cupule as to make splitting of the cupule unnecessary. Evidently the projections of the beech cup, the spines of the chestnut-bur and scales of an acorn-saucer are homolo- gous, as is also the main part of the cupule of each. But where are the bracts? Do the four divisions of the ripened beech cup and chestnut-bur correspond to so many bracts which in the acorn-saucer remain coalesced? In that case the various outgrowths from the cupule would be regarded as mere projections like the spines on a leaf. This view is held by many botanists. Others maintain that the projections, spines, and scales are the free tips of bracts which have coal- esced by their bases to form the body of the cupule. On this view the cupule would be an involucre of many instead of but four bracts. A third view regards the main body of the cupule as stem, that is to say, as a cup-like development of the secondary peduncle, bearing numerous bracts. Thus regarded, the acorn scales, the beech-nut projections, and the branched spines of the chestnut-bur, are homologized with bracts which are entirely distinct and free from the concave inflorescence-stalk. This last theory seems to be the one most easily reconciled with the facts as they appear in other members of the family as well as in those we have studied.? 1Cu'pule < L. cupula, diminutive of cupa, cup. 2 This is the view adopted in our formulas. 7 does duty for the axial part of the ultimate inflorescences; jj ~ following shows that it becomes woody and cancave like a perigynous torus; while < 4 shows that it dehisces into four valves; or < that it is indehiscent; and B/ ~ that it bears numerous dry bracts. The other parts of the formulas should be readily understood from what has preceded. 376 VARIOUS PLANT GROUPS The family consists of woody plants without oil reservoirs or resinous excretions; but with simple, stipulate leaves; and monecious inflorescences, the staminate mostly amentaceous, the pistillate more or less enclosed in a cupule, which bears dis- tinct, scaly, or spiny bracts; and the pistils of three or more carpels with axile placente. 124. The beech order (Fagales) comprises only the birch and the beech families. These agree in having monecious inflorescences with the staminate flowers mostly in aments, and the pistillate in spikes or heads; the flowers hypogynous or epigynous; the perianth leaves and stamens distinct and alternate; and the ovary with axile placenta, and more or less completely divided into two or more cavities, all bul one of which becomes obliterated in the fruit. See pages 414, £15 for the formula of Fagales. 125. The walnut family (Juglandacez). Examples: wal- nut (Fig. 27, page 39), butternut (Fig. 28, page 40), pecan (Fig. 29, page 40), hickory (Fig. 30, page 41), and black walnut (Fig. 246, page 260). Formulas of Juglans, Carya, and Juglandacee are given on pages 414, 415. In general appearance the inflorescences of the walnut family resemble those of the beech and the birch families, but there is a curious adherence between the bracts, bractlets, and perianth leaves, unlike anything we have seen. Those which belong to each flower are all more or less united to form what at first sight might be mistaken for perianth alone, The fruit is mostly a drupaceous nut recalling the almond, but with the tough fleshy part dehiscing into four valves and differing also in having the epigynous torus as a component part. The walnut family may be distinguished as consisting of trees with scented, pinnately compound, exstipulate leaves; and moneacious inflorescences, the staminale amentaceous, the pis- tillate in heads; each pistil of tivo carpels; and the fruit a de- hiscent drupe with a nut-like stone. 126. The walnut order (Juglandales), contains only the THE CROWFOOT SERIES 377 family from which it derives its name. It is distinguished from the other orders with monecious inflorescences, staminate aments and prstillate heads, by having the perianth leaves or the epigynous torus adherent to the bractlets and bract of each, and the ovary with but one cavity and one ovule. The formula of Juglandales is given on pages 414, 415. 127. The willow family (Salicacez). Examples: willow (Figs. 228 I, II, pages 243, 244) and poplar (Fig. 253, page 264). Formulas of Populus, Salix, and Salicacew are given on pages 414, 415. Much simpler flowers are here shown than any previously mentioned, although scarcely any new features are pre- sented. The torus while cup-like in the poplars, is represented in the willows by one or two glandular projections which secrete nectar. It is plain that ‘a cup divided, or failing to develope, at one or two places would be reduced to such flat projections. A peculiarity of the fruit of both genera is that its two carpels dehisce along their dorsal sutures exposing the small hairy seeds to the wind. This family which contains only the two genera mentioned, is composed of woody plants without oil reservoirs, but some- times with aromatic resinous secretions; the leaves simple and stipulate; the inflorescences amentaceous and diecious; the pistil of two carpels with parietal placente; and the fruit a capsule with numerous tufted seeds. 128. The willow order (Salicales) contains only the above family. Diecious aments of flowers without perianth but with numerous ovules, perigynous (?) torus, and free bracts, distin- guish this from the other orders. The formula of Salicales is given on pages 416, 417. 129. The crowfoot series (Archichlamydez). A general view of all the orders which we have thus far studied shows them to agree (with but rare exceptions) in having no coales- cence among the petals. All the leaf-parts of any flower are at first similarly distinct as they arise in the bud. Some- 378 VARIOUS PLANT GROUPS times petals do not appear at all, but when they do it is as distinct projections from the torus, comparable to the first rudiments of foliage leaves as they form near the tip of a developing shoot. The same is true of sepals, stamens, and carpels, as illustrated in Figs. 298, 299 I. If, however, a gam- osepalous calyx, a monadelphous andreecium, or a compound pistil is to be produced, it happens sooner or later that those Fig. 298.—Flower of Rose (Rosa alpina, Rose Family, Rosacew) in early stages, cut vertically and enlarged. A, the sepals (k) are well de- veloped, but the petals (c) and the stamens (a) are just appearing as minute knobs. 8B, sepals, petals, and stamens further advanced; and the pistils (g) just appearing as knobs on the dome of the stem-tip. C, later stage. JD, still later stage in which the parts are still developing in the bud. (Payer.) parts of the ring which connect the original projections begin to grow and the distinct parts are carried up on the rim or the tip of a tube or united mass of organs. Flowers which as they develop retain the original distinet- ness of their petals, or which develop none at all, are termed archichlamydeous.' Such flowers, we have seen, characterize the crowfoot series which includes all the orders we have studied and a number of others resembling them in the pe- culiarity noted. 130. The heath family (Ericacez). Examples: wintergreen _ | Ar’ chi-chla-myd’e-ous < Gr. arehi, first; ehlamys, mantle; imply- ing that the corolla, likened to a mantle, retains its original condition. VARIOUS PLANT GROUPS 379 (Fig. 147, page 148), mountain laurel (Fig. 189, page 202), and sheep laurel (Fig. 190, page 202). Formulas of Gaultheria, Kalmia, and Ericacee are given on pages 416, 417. A corolla with the petals coalesced, as in the examples here given, is termed gamopetalous,! a corolla with distinct petals being choripetalous.? When anthers open by pores the dehiscence is said to be poricidal as in the case of capsules which open similarly. It will be noticed that the capsule of mountain laurel (Kalmia) dehisces by splitting through the partitions. Such dehiscence is distinguished as septicidal.* The fruit of wintergreen (Gaultheria) is peculiar in having a loculicidal capsule enveloped in a fleshy enlargement of the calyx and torus. The typical members of the family are woody plants, often aromatic; having simple, eastipulate leaves; and perfect, gamo- petalous flowers, with poricidal stamens, and a compound pistil, superior or inferior ovary and axile placente; the fruit being capsular, or berry-like. 131. The heath order (Ericales) includes several families associated with the above through having mostly regular and perfect, usually gamopetalous flowers, four to ten stamens nearly or quite free, the anthers mostly poricidal, and the ovary compound, with axile placente. The formula for Ericales is given on pages 416, 417. 132. The morning-glory family (Convolvulacez) is well exemplified by the sweet potato (Figs. 56, 57, pages 58, 59). Formulas of Ipomoea and Convolvulacez are given on pages 416, 417. The new features to be noted here are the exstivation of 1 Gam’o-pet’al-ous < Gr. gamos, union; petalon, flower-leaf. P). 2 Cho’ri-pet’al-ous < Gr. choris, separate. ; 3 Sep’ti-ci’dal < L. septum, partition; cedire, cut. Indicated by the sign /. 380 Fia. - ing the corolla-tube (¢c) with VARIOUS PLANT GROUPS 299, I—Flower of Oxeye (Heliopsis scabra, Sunflower Family, Composite). Gr. pappos, grandfather, applied to the thistledown in allusion to white hair. STC7. 2 Met’-a-chla-myd’’-e-ous < Gr. meta, beyond. 3 Di’’cot-y-led’on-ous < Gr. dis, two; kotyledon, sced-leaf. THE GRASS FAMILY 387 are called exogenous 1 or outside-growing, because new wood when formed is added on the outside of an older ring. 143. The grass family (Graminz). Examples: oat (Fig. 1- 4, pages 12-14), rice (Figs. 5, 6, pages 16, 17), rye (Fig. 7, page 18), wheat (Figs. 8, 9, pages 19, 20), barleys (Figs. 10-12, pages 21, 22), maize (Figs. 13-15, pages 238, 24), sugar-cane (Fig. 114, page 106), broom-corn (Fig. 222, page 236), and bamboo (Fig. 224, page 239). Formulas of Zea, Saccharinum, Andropogon, Oryza, .Avena, Secale, Triticum, Hordeum, Bambusa, and Gramineze are shown on pages 420-423. The grasses introduce us to a new sub-class, characterized partly, as we shall see, by having the leaf-veins running in a regular, more or less parallel system. Leaves with such a framework are said to be parallel-veined. Grass leaves always have the veins running lengthwise from base to tip. Other noteworthy features of grass leaves are that the base is wrapped about the stem so as to form a sheath the edges of which overlap as shown in Fig. 13; and the blades extend from only two sides of the stem, thus coming into two vertical ranks. Most grass stems are round and hollow like straws. Rarely, as in the stalk of maize, there is a solid cylinder of pith, through which run scattered bundles of firmer, more or less woody material, not forming true rings, but often so crowded toward the surface as to constitute a somewhat bark-like zone. From an erroneous idea that these scattered bundles originated near the center of the stem and were forced out- ward by new growth, all stems with scattered bundles were early described as ‘‘inside-growing”’ or endogenous >—a term still used conveniently, however, by way of contrast for stems of seed-plants of the non-exogenous type. The bracts and bractlets of grasses in general are com- paratively thin and stiff, like the husks or chaff of grain, and have received the special name of glumes.* 1 Ex-og’en-ous < Gr. ezo, outside; genes, producing. 2 En-dog’en-ous < Gr. endos, within. 3Glume < L. gluma, husk of corn. In our formulas the glumaceous character is denoted by the inverted exclamation mark as in Bj. 388 VARIOUS PLANT GROUPS The grain-like fruit of typical grasses resembles an achene in being the product of a simple pistil with one ovule and in being dry and indehiscent. It differs mainly in having the seed-coat adherent to the pericarp. A fruit of this kind is distinguished as a caryopsis. As shown in Fig. 9 the embryo is placed at one side of the albumen. On the side toward the seed-food is a some- what shield-shaped organ, termed the scutellum,? through which the germ absorbs its nutriment when sprouting. Mor- phologically the scutellum is regarded by most botanists as the cotyledon of the embryo, enlarged and otherwise modified for its peculiar function. Unlike the embryo of dicotyledon- ous plants, the embryo of a grass, as of all the sub-class of seed-plants now to be studied, has but one cotyledon and is hence described as monocotyledonous.* Grasses may be easily recognized as mostly herbs with hollow, cylindrical stems; parallel-veined, two-ranked sheathing leaves; flowers enclosed by glumaceous bracts; and fruit a caryop- sls. 144. The grass order (Graminales or Glumiflore) com- prises grass-like plants with ghumaccous bracts, a one-celled superior ovary, and a solitary ovule. The formula of Graminales is given on pages 422, 423. 145. The palm family (Palmacez). Examples: coconut (Figs. 34-36, pages 46, 47), date (Figs. 108, 109, pages 100, 101), sago palms (Figs. 116 I-III, pages 109, 110), rat- tans (Iigs. 223 I, II, pages 237, 238), and vegetable ivory (Figs. 266 I, II, pages 275, 276). The formulas of Phanix, Cocos, Calamus, Metroxylon, Phytele- phas, and Palmacex on pages 422, 423. Although in our examples the leaves are all pinnate and compound, many members of the family have simple palmate leaves, as for instance those from which the familiar palm- leaf fans are made. 'Car’’y-op'sis < Gr. karyon, nut; opsis, resemblance. Its mor- phology is indicated in a formula by [CH]; < G/N. 2 Seu-tel’lum < L. a little shield. 3 Mo’’no-cot/’y-led’on-ous < Gr. monos, one. THE ARUM ORDER 389 The flowers of palms are borne on a fleshy rachis which is more or less branched and subtended by one or more large, thick bracts. Such a fleshy spike whether simple or branched is called a spadiz,' and the large bract subtending it a spathe.? Palms may be distinguished as woody plants, usually with columnar trunks; large, plume-like or fan-shaped leaves; flowers on a mostly branched spadix formed within a spathe. 146. The palm order (Palmales or Principes) includes only the family of palms, which from their majestic appearance and high importance were well called by Linnzeus the Princes of the Vegetable Kingdom. From other orders the woody trunks, large and often compound leaves, mostly branched spadiz, conspicuous spathe, and the superior ovary with one or more cells, and one or more ovules, will generally afford sufficient marks of distinction. See formula of Palmales on pages 422, 423,. 147. The arum family (Aracez) is exemplified by Acorus (Fig. 167, page 174.) See formulas of Acorus and Aracee on pages 422, 423. Although the members of this large family differ very much in general appearance and in many details of structure, our common sweet flag represents quite well their essential fea- tures. Asin the palms, there is a spadix, although it is always simple; and there is a spathe which, unlike that of the sweet flag, is generally highly colored. In our example, moreover, the spadix, while appearing as if lateral, is in reality terminal, having been pushed to one side by the peculiar elongated spathe which appears to continue the stem. The family may be defined as consisting of mostly perennial herbs, sometimes aromatic, often wl-smelling or acrid; with leaves of varied form, often netted-veined; and flowers in a sim- ple spadix, subtended by a more or less petaloid spathe. 148. The arum order (Arales or Spathiflore) comprises 18pa’dix < Gr-spadiz, a palm-branch. 2Spathe < Gr. spathe, a broad flat blade or spatula. The exclama- tion marks used in the formulas after I and B indicate, as usual, the fleshy character, and the oblique line after B, its involucral nature. 390 VARIOUS PLANT GROUPS but one other family besides the above. Both are made up of herbs with leaves of varied form, sometimes rudimentary or absent; regular flowers in an unbranched spadix, with one or more spathes; and the superior ovary having one or more cells and one or more ovules. See formula of Arales on pages 422, 428. 149. The rush family (Juncacee) is typified by the com- monrush. (Fig. 221, page 234.) See formulas of Juncus and Juncacee on pages 422, 423. At first sight the rushes appear somewhat similar to grasses, and indeed certain botanists have regarded them as belonging to the same order. The resemblance comes chiefly from the grass-like leaves of many species and the glumaceous charac- ter of the perianth.t| The family may be defined as herbs with regular flowers having a glumaceous perianth, either six or three stamens, and a superior, compound ovary. 150. The lily family (Liliacee). Examples: onion (Figs. 60, 61, pages 63, 64), asparagus (Fig. 62, pages 64, 65), Indian poke (Fig. 186, page 199), and lily-of-the-valley (Fig. 193, page 204). Formulas of Allium, Asparagus, Convallaria, Veratrum, and Liliaceze are given on pages 424, 424. One of the largest and most important, the lily family is generally easy of recognition as being composed mosily of herbs with regular flowers having a petaloid perianth, six stamens and @ superior, compound ovary. 151. The iris family (Iridaceze) is represented by saffron (Fig. 168 II, page 176). See formulas of Crocus and Tridacex on pages 424, 425. The Iridaceze are herbs having flowers like those of the lily family but with only three stamens, and an inferior ovary. 152. The lily order (Liliales or Liliiflore) comprises several families which are like the lily family in being mosily herbs with leaves of varied form; inflorescence never spadiceous ' Indicated in the formulas by the inverted exclamation mark. THE CASE-SEED CLASS 391 though sometimes spathaceous; flowers mostly regular; the ovary compound, superior or inferior; and seeds of moderate number and mostly medium size. See formula of Liliales on pages 424, 425. 153. The orchid family (Orchidacez). Examples: vanilla (Fig. 1481, page 149) and lady’s-slippers (Figs. 212, 213, page 220). See formulas of Cypripedium, Vanilla, and Orchidacee on pages 424, 425, Although in the flowers of this family we can recognize the fundamental type of structure exhibited by the lily-like families, it is here modified by many curious and elaborate complications. .An orchid might be described as a lily with irregular perianth, one or two stamens inserted upon the style, the other four or five being suppressed or represented by staminodes, and with an inferior ovary so twisted as to bring the flower upside down. A flower thus turned is said to be resupinate.. However obscure the morphology of special parts may sometimes appear, orchids may usually be recognized as perennial herbs, with irregular, resupinate, epigynous flowers, having a petaloid perianth, one or two stamens adhering to the style, and a capsular fruit with exalbuminous seeds. 154. The orchid order (Orchidales or Microspermez) con- tains but one other family. This agrees with the orchids in comprising herbs similar to the epigynous families of the lily order but forming innumerable seeds of exceedingly small size. See the formula of Orchidales on pages 424, 425. 155. The monocotyl subclass (Monocotyledones) is made up of seed-plants having a monocotyledonous embryo, en- dogenous stem, and mostly parallel-veined leaves. Together with the dicotyl subclass they constitute 156. The case-seed class (Angiosperme) which includes all the flowering plants forming their seeds in a case or ovary 1 Re-su’pi-nate < L. re, back; supinare, bend. The twist is indi- cated in a formula by ® placed after T. 392 VARIOUS PLANT GROUPS consisting of one or more carpels—or in other words—all that have an angiospermous ' gynoecium. Nearly all seed-plants belong to this class. 157. The pine family (Pinacez). Examples: juniper (Fig. 154, page 158), pine (Fig. 258, page 269), larch (Fig. 259, page 271), spruce (Fig. 260, page 272), red cedar (Fig. 261, page 273), redwood (Fig. 262, page 273), and hemlock (Fig. 263, page 273). See formulas of Pinus, Larix, Picea, Tsuga, Sequoia, Juniperus, and Pinacexw on pages 424-427. A considerable variety of opinion obtains among botanists regarding the morphology of the floral parts of the pine family. According to one view the catkin-like clusters, or at least the seed-producing ones, are aments of very simple flowers; while according to the other view what appears to be a catkin or spike is a cluster of stamens or of carpels, and thus represents a many-stamened or many-carpelled flower. Without discussing the relative merits of these rival inter- pretations, we may provisionally adopt the latter as being the simpler view and as best serving our present purpose.? The carpels differ from those of the ease-seed class (Angio- spermie) in being flattened structures; hence the ovules are exposed, or at least are not enclosed in an ovary. The gyne- cium is therefore called “naked-seeded”’ or gymnospermous.3 In fruit the gyneecium and elongated torus form a cone with more or less woody scales and axis; or, as in the junipers (Juniperus), these parts may become fleshy and consolidated into a berry-like fruit. The great majority of the pine family are easily recognized as more or less resinous, mostly evergreen trees, producing cones. 158. The yew family (Taxacez) is exemplified by the yew (Fig. 204, page 213). See formulas of Taxus and Taxacew on pages 426, 427. Simplification of floral parts here reaches an extreme. In ! An’gi-o-sperm’ous < Gr. aggion, a vessel; sperma, seed. ° In the formulas Tj indicates that the torus is here regarded as anal- ogous to an ament rachis. * Gym"no-sperm’‘ous < Gr. gymnos, uaked; sperma, seed. THE SEED-PLANT DIVISION 393 the yew (Taxus) not only is the perianth lacking and the andreecium reduced to a few stamens, but the gyncecium is only a solitary ovule borne directly upon the torus and with- out a carpel. This ovule ripens usually into a hard seed which is surrounded by a fleshy envelope formed by the upgrowth of a ring which at first encircles the base. Such an accessory seed-covering growing from below is called an aril.t| In other members of the family the staminate flowers are more cone-like, and there are a few with much reduced carpels each bearing a single ovule which may ripen into a drupaceous seed. The family consists of mostly evergreen, woody plants, with comparatively little resin or none at all; having cones much reduced, or else the ovules solitary and without carpels; and the seed arillate or drupaceous. 159. The pine order (Coniferales or Conifer) comprises only the two families given above. They are distinguished as woody plants, with branched stem; unbranched, usually narrow, leaves; and imperfect flowers which have no perianth, but are often catkin-like, and commonly produce cones. See formula of Coniferales on pages 426, 427. 160. The naked-seed class (Gymnosperme), embraces only a few orders besides the pine order, with only one or two families in each. They all agree in being seed-plants with gymnospermous gyncecium, and are for the most part destitute of perianth. 161. The seed-plant division (Spermatophyta) is coexten- sive with that branch of the Vegetable Kingdom commonly known as Phanerogamia, phenogams, or flowering plants, because characterized by the production of flowers contain- ing at least either pollen-sacs or ovules. Since the produc- tion of seed is the function of these parts, and since no other plants produce true seeds containing an embryo, it is equally appropriate to speak of them as seed-plants, seedworts, or spermatophytes. The system of classification (although not always the sequence of groups) adopted in the foregoing pages is sub- tAril<. L. arillus, a dried grape (for no obvious reason). 394 VARIOUS PLANT GROUPS stantially that of Engler and Prantl whose great work on the natural families of plants is now most generally followed, at least, with regard to phenogams. In this classification there are recognized among seed-plants about fifty orders and two hundred and eighty families. The eighteen orders, thirty-two families, and about a hundred genera of seed-plants included in this chapter are represented by formulas on pages 404-427 in order that the student may readily compare the more important structural characters of one group with those of another, and so gain a better grasp of the abstract ideas underlying a natural classification. Taken in connection with the accounts of the various groups given in the sections referred to by number before each formula, and with reference to the figures indicated in each section, the formulas will afford a most profitable means of reviewing the many details already studied, and will re- veal some of their wider relations. 162. The vegetable kingdom (Vegetabilia) which includes all plants is regarded most conveniently as consisting of four main divisions assumed to be equal in rank.! The highest division, that of seedworts or spermatophytes, includes most of the forms we have been studying. These agree not only in producing seeds but also in having true roots, stems, and mostly green leaves, all traversed by more or less woody strands, known as jfibrovascular bundles, which form a framework or skeleton, and conduct nutrient juices to every part. True roots, stems, and green leaves, all provided with fibrovascular bundles, occur also in such plants as the male- fern (Aspidium, page 179) and the club-moss (Lycopodium, page 174); but these plants propagate by spores developed in minute spore-cases, and never produce seeds. Plants thus characterized form the pteridophyte or fernwort division. (Pteridophyta). Next to these come such plants as peat moss (Sphagnum, page 242) which propagate by spores similar to those of fern- worts but contained in more or less urn-like cases commonly much larger than fernwort spore-cases, and usually borne on This view differs somewhat from that of Engler and Prantl, but best suits our purpose as being the one most widely adopted at the present day. THE VEGETABLE KINGDOM 395 conspicuous stalks; but these plants have no true roots, stems, or leaves with fibrovascular bundles, although often possessing very simply constructed parts resembling small roots, stems, and leaves. Humble green plants of this descrip- tion make up the bryophyte or mosswort division (Bryo- phyta). Finally come such comparatively simple forms as the so- called Iceland moss (Cetraria, page 169), the field mushroom (Agaricus, page 113), and the carrageen (Chondrus, page 112) which, although commonly propagating by spores that are sometimes in cases, have the cases either stalkless or other- wise plainly different from those of mossworts. True roots, stems, leaves, and fibrovascular bundles are never present, although the plant-body may be so lobed as to resemble somewhat that of higher plants. Hence these lowly organized plants form what is known as the thallophyte or lobewort division (Thallophyta). Our three examples of the lobewort division each represent one of its three subdivisions. These may usually be dis- tinguished by their different modes of life. The Iceland moss is an air-plant merely resting upon barren soil without having any means of drawing much nutriment from it, and is con- sequently dependent upon what it can get from the air. This mode of life is made possible by the somewhat spongy nature of the plant-body in which are embedded minute containers of chlorophyll that may become apparent upon wetting. Plants like this so-called “moss” which thrive in barren places such as the surface of rocks, bark, dead wood, and sandy soil are of the lichen subdivision (Lichenes). The field mushroom differs from all lichens in being entirely destitute of chlorophyll because it feeds directly upon animal or vege- table manure in the soil. Lobeworts which can thus dispense with chlorophyll by feeding upon animals or plants or their decaying remains are of the mushroom or: fungus subdivision (Fungi). Aquatic lobeworts, whether of fresh or salt water, which like carrageen contain chlorophyll (sometimes more or less obscured by red, brown, or blue coloring matters) form the seaweed or alga subdivision (Alga). The following synopses show in tabular view the divisions 1 q oO VARIOUS PLANT 396 ‘(VLAHAOLVNUGdG) SLUOMGAAY ‘SENVIG DNINAMOTY ‘SWVDONGHY ‘NOISIAI(] ALAHdOLVIWaady : [44d O10] YO WMOYITA JO PIM {spaos Suronpoid suvs1o0 Y}IA ysvop 9B LO ‘suaMoy ond} ICM *(VLAHA -OdIUALY) SLUIOMNUAT ‘SHVDOLEAUD UVIAOSV A ‘NOISIAIG: ALAHAOaTAALY :[[Ayd -OLOTYD YAK SATA {S[IXB TOT} UL IO SoAveT oy} UOdN oULOg sosvo a]NUIUE LO [PLUS ul poonpoid sorods Aq Agetqyo Surjesvdoid yng ‘spoos 10 S1oMOY OMI} LOY }IO FNOYITAL ‘(VIAHdOAUG)) SLIOMSSO] ‘NOISTAI(] ALAHAOAUG !Y[CIS Jopuyys v uodnN oulog AyPENsn st pur ‘sys Aq Io pry v Aq suodo [orp osvo oyT]-WaN [PRUs v UL ATJSour sviods Supnpord puv ‘TAydoropyo TILA, ‘(SANGHOI'T) NOISIAIGGAG NAHOTT :joM voy | ydooxa =yuorrdde you fAqdoso[yo !yueuaynu Joy ae oy} uodn Aporys Surpusdep ynq ‘oly at} pue [los UodINg YYreq ‘syoor OF payor} ye SULATT | “(IDNO YY) NOISTATAH OG BUABep Tay} UO 1O sjuR[d JO syeuTUv UO SuLAry } ‘(VLXAHdOTIVH],) SLUOM -a0'7T ‘NOISIAIQ @LAHAOT (HDTV) “VAL :Y[eIS Jopusjs v uo NOISIAIGGOG GaaMVag :jueuIsId ped IO ‘UMOIG oso oYl-Wan [Tews v UL JOU ‘antq Aq poYysvur ssop JO alow aq AvUT YOTyAL sorods otf} TTAYCoaoytpo YA JL [Aqdosopyo BururezUoo {1ayVA FCS IO YSodJ ULBULATT | PAYdoropYo yNoy}I IO YITAL WOGDNIY ATAVLEDAA AHL dO SISdONAQ TVYUANGAY) - ‘SINVIG UVTOOS¥ A PYLOMOUICIF IvpNoseaoiqy ev puv ‘ssAve, pu ‘suIo4s ‘s}oOI ond} UUM ISNVDOLIAUD UVIAT -TAD :SIXv oyl[-Uleys v Suope poepMordo sotutjauros suotsurd -Xo dYI][-JCoT JO Soqoy FILM 10 {S}00d SUT[QUIOSAISSo] IO e10UL SYJMOISINOG YL wsZjo ynq ‘yIOMoUIvIF IvpNOsvAoIqy v Buryory puv ‘saavo[ JO ‘ulo}s ‘sj001 ond} NOY APOd-jUL[g Apoq-juv[q 397 a is ROUP 1 X VARIOUS PLANT G (MarvpryotO) “WY PIYPO “LT J AO T “Vs SAV[NZa1st "BH ) : (SaTVPIYIIO) ‘O PIYdIO :snoutwunq]exa “ps (Ma9dD.L9QUULZ) “WY 496WI) “OT SoTBUIUIe;IIG) "O vURUEg (maoDSiyE) iT DUBUD “Gp kee eS Nees eer ae ta ee SE projejod ‘ssaj Io G “Ry (waovpwy]) “YSU FT “By \ + (S9TBILTT) rusting. — | DIIVPYRLDUW YP) “Y Sypiavwp “ET oe $ TeeO Ey t isnouAside "yp ‘oO ANT Auioy 10 PY V) a Stl } , (pavyrT) “a ALYT “Za : “sg ‘ey Spropeqged “ds iproyeyod Aysop (maovduNp) “Ye YSNY “TT “-"g 10g “By tsnovovunys ‘ds f :snouAZodAy ‘yg } you ‘9 10 E “By WIL “ps | ***:propeyed ‘ur ‘ds fsnoovvueiquieul “q (DIIdUIIMWO,)D) “yf Mensapidgy “OL *:payniedos sovs-uayjod tssa] 10 g "vy | °°: (SeTeplwAy) “OQ SsBIg) pata isnosotpeds jou (wo0v29WoLG) “yw ajddvaurd ‘6 “os :payuindes you soes-uajjod +9 ‘vy | -Moyjax :uouNg]e Ave YyTA "ps ‘asoUlootd “UL “T (maoDLy) “YE wnty “Ss “ i(sayery) °C WNIV:9-[ “Vy :shosvovqioy as | sores srg ao Aysapg ‘Arp ‘ds (w220U]Dq) “Yo upDd *L i (sayemMyeq) "O Weg ‘9 ‘WB :Apoom "4s | ‘snosovyyeds *q ‘snosoipeds “Tt (waon1adh)) “yy aOpag "9" “SU QBOYS Pasofo YFLM "| !AvpNSuLLy = ‘pros “ys | °° *: (SaTBUTUTeID) ‘O ssBID ‘9 ‘UI “ds (waurmovsy) “y sspuy *G °° ssqyveys yds YyLA ‘| /pouezzeY JO punod ‘Moyjoy ‘wT “ys J ‘snosoeuINys *q ‘ezepnorued 10 oyeoIds “WT (meovurg) “ay autg “pocic Setue GANG Mods ROME Sade “ssganoq 41o soeuoo ul ‘AUOG JO AIp !poe]veUOo “ps :s9uU0d BULUTOJ ‘9 "OO } °° 7 (SaTBIaJIMOD) *G aul (waovrvy) “Yq nat °*S “-rpue Adjnd yy 10 snosotdnip ‘pasodxo “ps ‘auou JO Maj ‘ad | :07ey809 “UO ‘a[duts ‘| | poyouriq “48 (Wasmabsuae) Pr Obyway NZ PE sonst steric iceesaee iret tate ts antes :(SaTBOZHUID) *O OBHUID :poasou-uvy ‘o]duris "| !paeqyouraq “4s (Ma0vpvoAi,)) *Yy PRIAQ “T (soTBpBohD) ‘CE pesdD :punoduroy Ajayvuuld wi *| !paqouviqun ‘ur 4s (WACAWVIHOVEATY ) SLOOIG UAHOIL ) ‘salugdg UTMOTATIAG :62 “Xo ‘poywun +— 'd| (@TALOOIC) SLOOIG ‘SSVIOGAg TALOOICL (@WUAdSOIONY) (Wad ANVTHOIBOUY) SLOOIC :Z SUOPa]A4Oo ¢8,¢ 10 8p UL “WI syed “f SWUAdSOIONY YVAMO'T ‘SAIUAG LOOAMOUD ‘yoUTSIp IO ‘Q ‘d SLOOONOJY | SSVIOGAG TALODONOJ : | UOpa]A}00 '8,¢ UI “UE sud “YS poulea-ja][eied “Ur “| ‘snousZopuea “uw “4s | (@ TALOOONOJY) (#NUAMSONNWAD) SWUAMSONWAY ‘SSVID dagas-dayvN :pouleaA-Jou “UT *] ‘snouasOxe ‘WI “48 [| ‘SSVID Gaas-asv—_) 1AO Pasojo B ul pouadi ‘ps “+ +1 00-g suOpa]A{}Oo !*AO paso[d B UI pousd you "ps “ATTIC “ SIOPAO “'O !poyroga-*qaa ‘oytsoddo ‘ddo ‘azvuse3]e “-q]B $07 ‘— isso] 1¢ 910UT ‘== {a1OUI 10 ‘4+ :AUBUT IO [RIoAVS '% + ATRyTOS *T :oUOU ‘C+ (A[tuIBy JO JaquINU Aq PaMOT]O}) UT satUTJaUIOS 4dao -x9 “xo {A]JSOUI “UT !spoos ‘ps !4INIy “Ay !SN10} ‘"} !AIVAO “AO Sso[NAO YYIA sjodivo “oo ‘s1oq]UT ‘“B sopoulMeys “y Ssioy}UT QTM syTOUT BIJ Jo ‘suoweys “ey /yjUeLed ‘ds ‘sejod ‘d sjedes “s ‘[e10g JO sIomog “BY ssyovig “q :voUeDso1OBUl “1 :saAva] “| /Ueys 148 :sUOT]VIADIQqY BLUOMGAAG AO SAITINVY AAYGNOW ANC JO SIBdONAIG SLOOONOJY :SWUAdISONWAY) ‘BSLUOMAAIS Q - Oo Ee Oo oH VARIOUS PLA 398 (waovpiivddv,)) “J 49dv) (Dleftons,)) “Ye PLOISN FL (waovsoavd vq) ‘yf fiddog (MagvINVT) “Ye PAnvT (wmaovoysriyy) “yp Gaupn ny (Pa DYJUDIPDD) *Y Qrays-hssagno.gy (wasp youbvyy) “ye vyoubv py (maopUmsad stu Fy) “ye paasuoo Py (maonpr9qiag) “Yq hasaqavg (DIIDjNOURUDY) “Wf poofmods,) (moovmydueiN) “yp APY-49IV Af (waonpfiydohsvy) “Ye yuri (MIIDIDIN}LO) “wy AUVISIN (wMaIvIIvIIINYT) “Ye Psawnayod (MIIDJUVIDULP) “yf YsuvivU (waovipodouay,)) ‘Y Joofasooy (waodu 0d) ‘dq PDayYNyong (parvyJUDLOT) “YW 90}22)SUY (M09D02)4)) “A AON (Daov.L0 J.) “A Aa«sggquryy (mo0DW7)) “A Vg (waIvbDy) “wf YIaT (p29D) NPI) “A YL (waoppuvjon ys) “gq MUD AL (maov1Uh TY) ‘qf fssoqhog (Baov22}D8') “A O72 AL (wavpi9diq) ‘yi 4addag “FP “St :paT[9o-T “Ao qasu9] tendo qnoqe JO ‘w-F “BY :(saTe | eee *pall-% G ips -Jaavdud) ‘AO ‘Suo] F pue yogs Z “Ul “Vy J ssnouTMINa]exo “ps | ‘oC Addog RS Sears eter :G ‘UL § ‘WeuING]e AylO Gy “ps } !poyun ‘+ % ‘90 :9 d ‘payran =: 'S {SdATVA YIM “ev 'E Jo EIOYM fF JO E UT ‘VF tment oe ; snoyd | sjepeuour "ey ssnowaip ‘Bg i :sjop 2 (SaTey speaoToy “4 \ °° youTySTp ]10 -nounu oyeDuo]o “yf ‘Vy Sjoojiod “gf [te ee | -eYy) ‘O pei es te yA BOATCA | Hainer Cf { yoo} qnoyyta “e todnip =e ‘ay | ssjyop | ‘+7 -d ~AsoIQ : PA YUAL TH "e !Aqaq v ‘ay } 110 ‘youn | tee mula * ISOA[BA yno -sIp ‘8 ia) a yg xe qnoqyis *"e + Aaraq e 10 AIp ‘Ij hee I: wo “Ul "Uy | -so1109 hy [ot sna ‘snout ce ae Hy] pedeys-ppeigs Sunwoy yy eee ayenbe | ‘%-][ ‘90 }) -Bod csednip Jo svavures ‘ry iy] “] 'des Aro}BA YAM 890d} | (saTeoIQ) ‘O 9HIeN (soTeseq) "CO qoe0g sayndna ul ‘oyty-gnu “api E790): J , rayeyndys ‘ajdurts ‘| royt-ou00 “Wi “ay 5 90 :(sapepurysnf) °O wUyeM :a}e|Ndysxo ‘ayvaurd *] i (saTVorsAYT) ‘OQ AJaqheg :ayvjndysxe ‘ojdars "| ) :snotsaMuoul “1 isnooovyuIue Arey “ps :ayejndys ‘ajduns "| : (sayeoyes) *O MOTTA ‘sholowtip “Tt “snouts ‘T ‘ps !powun ‘FT 82 !OT-T “vy :(seperedig) °Q zeddag :ayvords © asoulAo ‘UI * “we 10 ysta a13 : (sayerpodousy)) ‘0 JO0JaS00H “xa ( “d yeaymyong :plojejod "w* * tgadtd 10 yslusala soyistied Apoom :(safeyeyaeS) *Q poomyepueg :ployedes ‘uw “ds SLOT, | | | | 399 € PLANT GROUPS VARIOU (MarvYynIs9}G) “wy DYNILN (moody Fy) “A NoNd Fy (woovyat) “a UepUrT (maovp-.4) ‘ye edvLH (MaDUUMDYY) “yf ULOYIYONG (MaIdUDPSVIOAAIF]) “yw INUJSIYI-a8.L0 JT (DIVL99P) “Uf spdv yy (waov2]0f nb) “a ANOTT PLDIDUF) “yp sung quoydng) “wy abands DIIAY) “u] 9249-DUIYD (PIODINA) “A aN (wmaonphrowyihagq) “yf P2909 (Mao0UrT) “qi TV) (waovpryDzQ) “Y 8272TO (MIIdLUDLI!)) “A WNTUDAIE) (a: HVUNOIT) “vf ASIN (maovsoy) “qi asoy (D2IDUYjD) J) “YW 93-L7-2UD] I (waosvpryau dun FJ) “Ye 1920Y-YIMAL (Daovbvafirvg) “yf abvufirvg (maovjnssv4,)) “Yo 9urdi¢C *:poztun ‘8 ! parva -7no y aaraadé ‘3 sous uojjod 1MOJ “u JOPTUTL “8 + pas AA -jyno Sutuedo ‘T sous-uojjod too “uy SFO ees ; > :90USIp ‘8 !pava ‘O MOTBIT * -ul Sutgedo ‘Z sovs-dojjod {oo ‘ul “By | sdnois G10 [ 07 pus} WLM soulA Apooas tAqroq vay (soyeumeyqy) : ISOUTA ‘Oo Woy HONG Jo ‘sqnays ‘sary Aap 10 snosoednap “sy UIpudose "UT :pod Aroq To] ‘| srepnsout Yy (say -Bpuldes) ‘Oo Ip | Aiiaq-deog :dn ojsd -vdnap: “AF FW9OLFIOAD “CH -OLOTUL | -10p oudey Sulsuvy “UL “| J fanpnsor “BE sae gh etey rE ‘90 :(So]e oqny YP GTA ur -luv199) ¢ : you "| | spurs ursor ‘O wnIu “Cg “spun 10 wy M poyOp ‘| } AO [IO TPE -BIID “eS oitjue ‘ayd idan op Ad -uns “[ : posupuoddy ‘d !xpoom sol} -OLOTUL rorqua ‘ojdus *] -LABO ‘yeaqUOA 2998] 010}- ey AIOY aydes gyno :snoood -010908 410 paqo| Ajoyeuyed * -eqaoy nowy | -Saey sw peq I oy a sss r9uinsey @ tay fsnoyd -poptip ‘OL “ey ‘snoosnuorided “Ur “Bf ‘GR Terres aes “own rsnoloa1p -Hop B YOU “Aj $YOUTYSTP ‘oo “VF SavpNFoe1 “Be } 10 yooysod “Gg ss]yeq Ur ‘Apooas “ay fo}WOIOO “4B "| !s9o1} !snoloaMuou rpoj[ee-z ‘Apooar sop eae cL ae yuryd Apoom Qpat *rddo ‘] qyr gud syuyyd spoom Jo “y]U *] ygtas squay_ J's URYy JaaMay “90 “CF Sees “rsqroy El GA courbaril-tree, ete. 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Cle Eo NIGHTSHADE FAMILY CE 2) ES nS ci+,i Eo foxglove CE 2) Ee AN CiZ Eo FIGWORT FAMILY CE 2) ES ee CZ, Ex 417 G-N G-N G-N G-N TAN GAN gS ) = G an N G-N G-N 418 O al O,b O,b Oo 12/53 Li/it Lift Ll/,t Lit L!/,* Lif, + L'/,t Lift FORMULAS OF i) Iwo 7-9 To g-,: 9? Iwo 8 fo 8 8” 5), 3) P” 2) 973) PP) g78) P32) ars) Pegs s’3) PPR 973) pray Mentha (135) FA 2] Thymus FA3] Origanum FA 3] Satureia FA 2] Salvia FA 2)] 0 no LABIATE PA3] POLEMONIALES (136) 2 EPPS a5 aes see PNG a's Bes S75 -P”5) Bye. es) s°g Pay 5),2) P85), 2) FA 2-5] Cucurbita (137) FAv 2)2)),F3 Cucumis FAY 2)2)1, F3 Citrullus FAY2)2)1,F3 Lagenaria FAY 2)2)1,F3 Luffa FAY 2)2)1,F3 CucURBITACE.® FAY2)2)1, F3 Campanula (138) FA5 Lobelia FA 5)) mint CE 22-9 E thyme CE2+2 E3 marjoram CE 2+2 E3 savory CK 2+2 3 sage CEHE2+2) E3 MINT FAMILY CE 2+2 E3 PHLOX ORDER CE 5-2) Es- squash, ete. CE3 () E% cucumber, ete. 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BOP Ae El El El 419 420 O,b (@) @ <3 ie Lyi 4 LY, FORMULAS OF CAMPANULACE® Iw 8 8°5,2) P?’5,) 5) FAS5,) Helianthus (139) I s§ Blob S8’2+ P’5),5) FAS] Lactuca rae 8 B/« S*+ o P‘’5) FA 5) Artemesia Ii‘ e 9 Bia SO P’5),5) FADS) COMPOSITE Tit go B/a +,b8"5+ ~¢ +P"5),5) 0 FAS] CAMPANULALES (140) Teae6 Se P5,5),5),3) FAS,),)] Zea (143) T'i‘: 9- Bbi SPO FA3 Saccharum I‘i‘: 8 Bbi SPO FA3 Andropogon l'i‘: 8 oBbi SPO FA 1-3 Oryza Ti‘: 8 Bbi SPO FAG Avena T'i‘: g 6 Bbi SPO FA3 Secale Ta = Bhi SPO FA38 Triticum I‘i‘: 8 8 Bbi SPO FA 3 Hordeum Ti‘: 8,6 Bbi SPO FA8 Bambusa I'i‘: 8 9 @Bbi SPO PA 6+ BELLFLOWER FAMILY CE2+) Ea sunflower, etc. CE2() hii lettuce CE () Ei wormwood CE 2() Dal SUNFLOWER FAMILY CE 2() Ei SEED-PLANTS TU] TCi Tol PGI apy, TSCIi< ASS] TCi< ES] STCi< BELLFLOWER ORDER CE 2-5), () maize CE1 Ei sugar-cane CE1 Ei broom-corn, etc. CE1 Ei rice CE1 Ei oat CEI Ei rye CE1 Ei wheat CE1 Ei barley CE1 Ei bamboo CE1 Ei Tel Ta Bo [eB Ta [CEi< Ta [CEi< Aas b [CHi< TA [CEi< 421 G-N GIN G/N G/N GN G/N G/N G/N G/N GN 422 Li), LY/,th Li/\th LY, th LY, th Li), th L)/,,* th L'/, ! FORMULAS OF ['i'> 8 ~ Bbi ToBi lit 7: 9B 8"3 [veo By S*3 Ili? 3-9 B!/8"3 Ili? a 9 8BIY/S"3,1 I! a: 9Bl/a 83 I!,i: e@B!/ 8”3 I! B!/ 8’'3 I! 8 B!/ I! 8 ~ B!/ I! B!/ Ig I-83 SPO GRAMINE.® FA34 GRAMINALES (144) SPO P23 pea P’3 P” 3,) P” 5-10 P’ 3+ FA 3+ Phoenix (145) FA3x3 Cocos FA3x3 Calamus FA 3x3] Metroxylon FA 3x3] Phytelephas FA o PALMACE. FA 3x3 PALMALES (146) P3 SP” 3x3 SP’ 3x30 SP’ 3X30 FA 3x3 Acorus (147) FA3x3 ARACEE FA38X 30 ARALES (148) FA 3X 30 Juncus (149) FA 3xX3,3 JUNCACE.E FA 3x 3,3 SEED-PLANTS GRASS FAMILY CE1 Ei Ds [(CEi< GRASS ORDER CE1,2-3() Ei TA date CE3 Ei Ta Cil< El coconut ; CE3() Ei Ta Clill< El rattan CE 3) Ei TA Clii< E8 sago CE3() Ei, 3 PA Chi< E83 vegetable ivory CE5=) Ei TA CI< x EX PALM FAMILY CE3+,);0 Ei TA Clha< Ei+ PALM ORDER CE3,),Q HEi+ TA sweet-flag CE 3) EX TA Cl< EX ARUM FAMILY CE3+) Eo TA Cl< Ean+ ARUM ORDER CE 3+) Eo Ta rush CE 3),0 Ee& es Cid: Eo RUSH FAMILY CE8),() EgEt Ta orale Eo 423 G/N G-N G-N G-N G-N G-N G-N G-N G-N 424 FORMULAS OF Allium (150) o lh 1/ 8 Bi/. +) SP”3x3,) FA6] Asparagus ob Ly, I/¢ SP” 3x 3,) FA 6] Convallaria 2 Li, I's SP” 3x 3) FA 6] Veratrum ™ Li/, VYisee@eo SP” 3x 3) FAG LILIACE.B ob LY, I‘g pP?i3 <3; } LA 6] Crocus (151) A LY; Is SP” 3x3) FA 3] TRIDACE.B 2 Li/; Is SP” 3x 3) FA 3] LILIALES (152) Le, B/ DEA asc.) FA 3+, ] Cyprepedium (153) 2 Li/, I‘g eP x ei Ts RAS Vanilla an LY, Vs SP” ix3 FAtXf& ORCHIDACE.E a Ly I'g SP*ExE, Tex FAGK!?, PAY ORCHIDALES (154) ds SP" 3x 3,ixi FAG-1 Pinus (157) L/}/ 1/1-5 1g- SPO FA ln Oo Larix L! Li) & L3- 2 SPO PFA © ln Picea 5 Li/, Iy-9 SPO PFA © SEED-PLANTS 425 onion, ete. CE 3) Ei+ Ta Gis La G-N asparagus CE 3) EZ TA Crs Kx G-N lily-of-the-valley CE 3) LE A Gre La G-N Indian poke CE 3) LE Tes Ch LX G-N LILY FAMILY CE 3} Eg Leas Ci, ! LX G-N saffron, ete. CE 3) ES Tel Tera Koo G-N IRIS PAMILY CE8) Eo RSI PCI Hoo G-N LILY ORDER CE 3) Hesse ee} lady’s-slipper CE3 () J ES TIU]® ROT Eo G- vanilla CE3()] He TCO TCE. Lo G- ORCHID FAMILY CH 0 ] E as Ley Dv) TC Hae Eo G- ORCHID ORDER CE3),0,]) ES TU],9 pine CE « 3 Ty TiCii Bé2 G-N larch CE x 2 Ti TiCii ig 2 G-N spruce CE 3 Ti TiCii Hg 2 G-N 426 L/, Lt/y / L?¥/a4 FORMULAS OF Iv I¢¢@ SPO Tsuga FA Sequoia FA& Juniperus FA PINACE.E FA « Taxus (158) FAa TAXAcEe rA« CONIFERALES (159) FA o- hemlock CE E2 redwood CEa& E5 + juniper CEa E1,2 PINE FAMILY CE a Ez = yew Co Er YEW FAMILY C0-a2 Ei PINE ORDER CE o- E2 = SEED-PLANTS Ti Ti Tics Ti TiCii TiCii TC! TiCii,! Lg 2 Hig E1,2 E2+ Hitt Ejtfo CHAPTER XI KINSHIP AND ADAPTATION 163. The problem of origins. Winship among living things implies a common origin. We know that kin always resemble one another more or less closely, and this likeness we attribute to their inheriting similar features from the same ancestor. Two individuals which differ from each other no more than do offspring of the same parents, we re- gard as belonging to the same species; and because of such likeness among the members of a species we feel sure of their having descended from an original ancestor or ancestors which had essentially the same characteristics. No one doubts that all the kidney-bean plants in the world are the descendants of a plant or plants having the charac- teristic features of a kidney-bean; but, as we have seen, there are numerous varieties of this species which differ strikingly from one another, often more widely than do many species of the same genus. Why then may not all the species of beans be descended from amore remote ancestor, and so be as truly akin as the members of one species? And if the species of this genus are thus related why not also, though in less degree, the genera of the pulse family, the families of the rose order, the orders of the ease-seed class, the classes of the seedwort branch, the branches of the vegetable kingdom, and, indeed, all groups of plants and animals according to their several degrees of resemblance? Why may it not be true that a natural system of classification expresses kinship? To some readers it may appear profitless to pursue in- quiries so remote, and they naturally ask, How can we know or why should we eare about the origin of living things? Our answer must be that while of course we cannot know about this absolutely, we may be more or less sure that our conclu- 428 DOCTRINE OF SPECIAL CREATION 429 sions are right, and in so far as we really desire to understand the world about us with a view to living in it as best we may, we cannot help wishing to have our beliefs regarding origins harmonize with what we do know. So far as they are in accord with facts, such beliefs help us to put our facts in order so that we may use them to best advantage in living and thinking. Our supreme test of the value and truth of any such belief is the extent to which it enables us to fit fact with fact, and leads us to new facts of importance. Our method must be to apply this test to those beliefs which have been most widely held about the origin of living things. We may be sure that every such belief expresses important truths because of the many facts it must explain in order to be widely accepted. It is, of course, our business to seek truths of importance wherever they may be found, and to adopt the most promising belief until a plainly more truthful view is presented. 164. The doctrine of special creation. Linnwus embodied the belief of his own age and of former times in the famous saying, “We reckon so many species as there were distinct forms created in the beginning.” This belief assumes that in somewhat the same way as men have fashioned artificial objects for various uses, so superior beings or one Supreme Being of transcendent wisdom and power, created in the beginning originals of all the different kinds of plants and animals, fitting each to occupy its proper place, and endowing each with the power of perpetuating its like in progeny. In other words, all the living representatives of each species are regarded as the descendants of a first original or pair which was specially created by God, as a distinct and entirely new production, in the most suitable part of the earth, when the world was young; from which place and since which time the species has been distributed over the area that it now occupies. Furthermore, the peculiarities which characterize its living representatives are held to be the same that were impressed in the beginning upon the original progenitors of the species. The view above outlined is known as the doctrine of fixity of species, or special creation, or as creationism. Since it 430 KINSHIP AND ADAPTATION proved to be satisfactory to the best thinkers of many ages, including many eminent naturalists, it must have afforded a reasonable explanation of numerous facts, and we may be sure therefore that it contains important truth. A species does seem to be fixed in the sense of having nat- ural limits beyond which unlikeness among its members cannot go. Thus even breeders of domesticated varieties find that they cannot induce more than a certain amount of modification in any one direction. For example, careful experiment has shown that if seeds from a wild carrot be planted in rich soil, and then seeds from the offspring with largest root be similarly planted and tended, and the same process of selection and planting be continued for several generations, there will finally be obtained as large reoted plants as any in cultivation. But sooner or later a size is reached beyond which the root does not increase; and if the most highly cultivated carrot-plants scatter their seed over neglected ground, as too often happens, the plants which are thus allowed to “run wild,” as the saying is, soon become indistinguishable from the wild carrots which are pernicious weeds. Another common experience of breeders is their inability to obtain fertile offspring by mating individuals of different species. It is true that pollen from a white oak may cause the ovules of a post-oak to develop into seeds which may grow into trees perceptibly different from either parent; and such hybrids are occasionally met with in nature. But when carefully observed it is usually found to be true either that hybrids are incapable of bearing offspring, or that such off- spring as they have are apt to belong unmistakably to one or the other of the parent species. Many of the so-called hybrids of horticulturists are merely crosses between varieties of the same species and their fertility does not affect the above rule. Here, then, seems to be another definite limit circumscribing a species as if some law of fixity had been imposed upon it from the beginning. Many naturalists have maintained that in case of doubt as to whether two forms are true species or merely varicties, the power to produce perfectly fertile offspring may be used as a final test. Species thus viewed DOCTRINE OF ORGANIC EVOLUTION — 431 become definite units of classification, which although some- times difficult to separate in practice are in theory none the less absolute. Those who have studied plants and animals most closely have always marveled at the ways in which each kind fits its natural environment, that is to say all the conditions under which it naturally lives. Thus among plants the absorption of food materials and the making of food, its storage for future use and its protection from harm, require not only a perfect working together of parts within the organism, but a nice adjustment of all to the surroundings. The structural features and habits of behavior which enable any organism to meet the usual requirements of its life are spoken of as adaptations to its environment. Creationism views the wonderful adaptations of plants and animals as manifestations of the Creator’s wisdom in so forming the progenitor of each species that its descendants shall all fit well into the places they are to occupy. It recog- nizes kinship only among the individuals of a species. The resemblance among species of the same genus, or among the subdivisions of higher groups in a natural system, it regards as indicating merely similarities of plan which the Creator was pleased to follow, much as an architect uses similar features more or less varied in different parts of a design. 165. The doctrine of organic evolution expresses a some- what different view, which, however, is not so fundamen- tally opposed to creationism as might appear from the violent controversies waged between creationists and evolutionists during the nineteenth century. Evolutionists have repeatedly confessed their faith in God as the Author of the universe. Nor, as we shall see, do they deny that the descendants of a given organism may continue essentially unchanged for an indefinite period. As to adaptations, evolutionists have re- vealed a wealth of marvelously perfect examples greater than the creationists ever dreamed of. What then was the need of a new doctrine of origins? One reason for dissatisfaction with the old view was that the more thoroughly plants and animals were studied, the less did species appear to have such definite limits as the crea- 432 KINSHIP AND ADAPTATION tionists supposed to exist. Naturalists of eminence frequently differ widely as to the number of species into which the forms of a given genus should be divided. It often happens that one botanist recognizes several times as many species as another admits in the same genus. For example, one says there are but thirty species of rose, while another makes the number three hundred. Then too, the test of fertility in the offspring proved in practice to be disappointing. It was found that certain forms which no one had ever doubted to be distinct species did sometimes produce fertile hybrids; while, on the other hand, undoubted varieties hybridized imperfectly. Therefore, it was urged, if no one can tell which forms have come from one original ancestor and which from another, what is the use of supposing, as the creationists do, that resemblance between species means something entirely different from resemblance between varieties? Another weak point in creationism was its underlying idea that the plants and animals of to-day are of the same forms which have lived upon the earth from the earliest times. Geologists in their study of the earth’s crust found fossil re- mains of many species differing often greatly from any now living. As a rule the more ancient the forms, the less they are like those of modern times. That is to say, fossils show that old forms have continually given place to new ones dur- ing the course of geologic ages. Furthermore, contrary to the original supposition of creationism, that conditions upon the earth’s surface have remained substantially the same since the appearance of life, the rocks show that extreme changes of climate have taken place. For example, scored ledges, transported boulders, and other evidences of glacial action prove that during the last geological period, the region from Pennyslvania northward was buried under a vast sheet of ice much as Greenland is to-day, while long before that time the coal plants of Pennsylvania flourished in a climate of subtropical warmth. To these geological facts creationists adjusted their belief by supposing that the older species were destroyed when they were no longer suited to a changed environment, and that new creations adapted to the new conditions then took their place. Thus instead DOCTRINE OF ORGANIC EVOLUTION 433 of one beginning there were many. But if creation be con- ceived of as a frequently recurring process, why limit the frequency? Why not admit that creation is going on con- tinually and that each birth may be a new beginning? Such a continuous creation of new forms fitted to new conditions is precisely what evolutionsts suppose to have taken place. When a creationist comes to believe that the Creator is continually making new forms out of old ones, so that by the accumulation of small changes through many generations great differences result, his theory of creation has already evolved into the doctrine of organic evolution. Modern botanists adopt the evolutionary point of view. The word evolution 1 means primarily an unrolling or un- folding. A bud evolves as it expands into a flower. The oak evolves from the acorn germ. In this process of unfold- ing its possibilities the organism passes through successive stages each differing slightly from the one which went before, and from the one which follows; but showing extreme differ- ences between the earliest and the latest stages. The evolu- tion of a snecies is conceived of by analogy to be a similar unfolding of possibilities through a series of generations, in the course of which new features arise, are inherited, and become more and more pronounced as slight changes con- tinue to appear in parts which had already been slightly changed. Fundamental resemblances between any two in- dividuals or types are thus accounted for on the supposition that they have inherited from a common ancestor the feat- “ures they have in common, while the differences they exhibit are regarded as representing the sum of those small individual differences which have continually arisen and been trans- mitted along their diverging lines of descent. Hence, broadly speaking, the degree of likeness becomes a measure of the closeness of kinship. On this view it follows that a truly natural system of classifying organisms is an arrangement expressing degrees of kinship as inferred from all the resemblances and differ- ences that can be observed. If we knew enough about all 1 By-o-lu’tion < L. evolutus pp. of evolvere, unroll, unfold Wn/do-spore < Gr. endon, within. * Zy'’go-spore < Gr. zygon, yoke. *Gam/ete < Gr. gametes, a spouse. 5 Con” ju-ga’tion < L. con, together; jugare, join or yoke. THE GREEN ALGA 479 LH Fic. 310.—Grape Desmid. Germination of zygospore: A, protoplast emerging; B, protoplast beginning to divide in half; C, division nearly complete; D, division complete within the thin temporary cell-wall; E, the two desmids escaped from the wall; F, one of them dividing by fission; G, the fission nearly complete, #22. (DeBary.) Fig. 311.—Pond-scum (Spirogyra sp., Pond-scum Family, Zygnemacee). 1, segments of two thread-like plants beginning to conjugate by the protrusion of adjacent cell-walls toward each other. 2, later stages resulting in the formation of a zygospore (b). Much magnified. (Ker- ner.)—Pond-scums abound on the surface of ponds, forming masses of bright green color through the summer which turn brownish toward spring when conjugation takes place. 480 LIFE-HISTORIES in which the plants are unbranched filaments consisting of a single row of comparatively large cylindrical cells containing spiral, ribbon-like chromatophores, rather prominent pyrenoids, and co- pious cell-sap. Elongation of the thread results from fission of the cells much as in Nostoe; but with Spirogyra the more intimate union of adjacent cells gives rise to a multicellular individual rather than to a colony of unicellular plants. Conjugation takes place between cells of separate plants growing near together. Outgrowths from two opposite cells meet, and by absorption of the walls at the point of contact form a tube connecting the cavities. Through this Fic. 312.—Pond-scum. Germination of zygospore. I, resting zygospore; f, yellowish-brown layer of the cell-wall; e, outer layer of wall. II, the protoplast emerging from the old wall, covered by a thin wall (g) of its own. III, young plant beginning to form a thread- like row of cells by elongating and forming cross-partitions (w, w’); its small end (d) still within the old spore- wall, enclosed by the old cell-wall of the original plant whose conjugating-tube (c) is still visible. Much magni- fied. (Pringsheim.) tube the gamete from one cell passes into the other cell to form a zygospore. Germination takes place in the manner indicated by Fig. 312. What is here especially noteworthy is that in the conjugation of Spirogyra we have a simplest form of sexual reproduction. Whereas in Cosmarium the gametes are just alike, in Spirogyra the one which passes over might be called male, and the other, female, although before conjugation no difference between them is perceptible. Somewhat more highly developed in both the vegetative and the reproductive system are the green alge of the genus Ulothrix (Fig. 313) which consist of cylindrical cells forming an unbranched filament fastened by one end to a rock or other firm support. These filaments grow so crowded as to form THE GREEN ALG 481 a woolly mat which suggests the name wool-weeds as appro- priate for the group. A differentiation of the plant-body appears in a specialization of the lowest cell as an organ of attachment. This, therefore, is analogous to a root while the remaining green part has the function of a shoot. But Fig. 313.—Wool-weed (Ulothrix zonata, Wool-weed Family, Ulotrichacee). A, young plant with basal cell (r) serving as a root-like organ of at- tachment, azs, B, part of plant with escaping swarm-spores. Cc, single swarm- spore. D, ‘formation and escape of gametes. JH, free-swimming gametes. F, gametes conjugating. G, conjugation complete. Hy, zy- gote. J, zygospore after a period of rest. A, zygospore after division of its protoplast into swarm-spores. B-K, ago, (Dodel-Port.)— Abundant on submerged rocks, especially in fresh water. the resemblance not being one of homology, it will be most accurate for us to name organs of this kind pseudo-roots and pseudo-shoots respectively. Thallus' is a general term for any plant-body in which true roots, true stems, and true leaves do not appear. The pseudo-shoot of a wool-weed elongates by fission of its cells, each of which contains a 1 Thal’lus < Gr. thallos, a young shoot. 482 LIFE-HISTORIES single nucleus and a chromatophore in the form of a nearly complete hollow cylinder. Eventually in some of the cells (B) the protoplasm assumes a spheroidal form or may divide into from two to eight smaller masses each provided with a nucleus through division of the original one. These globular masses soon begin to move and presently make their way into the surrounding water through an opening in the old cell-wall. When outside, however, they are still surrounded by a delicate cellulose membrane, but this soon ruptures setting free the naked protoplasts. Each of these (C) is now seen to be some- what pear-shaped, with a colorless pointed end from which come four slender lash-like projections, called flagella... The rounded part is grass-green and contains a bright red granule termed the eye-spot. As soon as they are free, these naked protoplasts swim about with rapid motion, propelled by their lashing flagella. After a while they come to rest, secrete a cellulose wall, and germinate by fission, the lower one of the two cells first formed becoming the pseudo-root by elongation and attachment to the substratum, while the upper cell develops into a long green multicellular thread by repeated divisions. A naked motile protoplast, by means of which a plant is multiplied non-sexually we call a swarm-spore. Ulothrix repro- duces also by motile gametes in which may be discerned occasionally a slight inequality in size suggesting the beginnings of difference in sex although for the most part they appear quite alike. These sexual or subsexual gametes arise from the cells of the filament in much the same way as the swarm-spores do, but they are more numerous and smaller, and possess only two flagella (D, FE). They unite sidewise (F) with their tips together, thus producing what looks like a swarm-spore (@), with its four flagella, but which differs in having two eye-spots. A protoplast resulting from the fusion of two protoplasts, whether they be alike or unlike, is termed a zygote.? The zygote of Ulothrix soon absorbs its flagella (/7), becomes round, and secretes a cellulose wall, thus becoming a resistant zygospore ready for a period of rest. The zygospore germinates by forming several swarm-spores (4) each of which in turn grows into a thallus as already described. In the sheath alge (Coleochete) the thallus (Fig. 314), is in the form of a flat disk or cushion-like mass attached to some support by the lower surface. This disk as in the species figured usually consists of branching filaments which elongate by repeated division of the terminal cell and branch by its frequent forkings. (B,a-g). In other species the fila- 'Pla-geVlum < LL. a whip. 2 Zy'gote < Gr. zygolos, yoked. THE GREEN ALG 483 ments instead of being distinct grow together into a mass by the coalescence of adjacent cells. Many of the cells produce hair-like outgrowths, and they are all uninucleate. Any of the cells may form a single swarm-spore like that shown in Fig. 315 D, which, as will be noticed, has but two flagella. Sucha spore, after attaching itself to some support, divides into a cell-row Fic. 314.—Free-branching Sheath-alga (Coleochete soluta, Sheath-alga Family, Coleochetacee). A, plant showing flat system of branching, and bristle-like outgrowths (h), 172. B, part of disk, further enlarged; a-g show successive stages in the branching of terminal cells. (Pring- sheim.)—Thallus forming bright green spots on plants or other sub- merged objects in fresh water, in Europe and America. which by further division becomes a mature thallus. Besides this non-sexual method of propagation a well-marked sexual reproduc- tion takes place as follows. The protoplasts of certain small usually terminal cells (an, Fig. 315, A) become transformed into flagellate bodies like the swarm-spores only smaller (z); while other terminal cells (og, Fig. 315, A) enlarge, become flask-shaped by the formation of a long neck opening at the top, and finally contract the protoplast into a sphere at the base. The motile body as soon as it is set free swims to the flask-cell, enters the opening, forces its way down the neck to the large protoplast, and fuses with it. 484 LIFE-HISTORIES The smaller motile protoplast is plainly the male gamete, and the larger, non-motile one, the female. Hence the cells in which they arise may be called respectively the male and the female gametangia,' the cells in which non-sexual spores appear, being termed sporangia.?. Union of a male with a female gamete is dis- tinguished as fertilization. As a result of this process in Coleochete the fertilized gamete, still remaining within the gametangium, en- larges, and incloses itself in a new cell-wall, thus forming what is called an odspore,* which becomes further protected by an envelope of branches (7, Fig. 315 B); for a cell at its base is stimulated to Fic. 315.—Cushion Sheath-alga (Coleochete pulvinata, Sheath-alga Family, Coleochetacee). A, part of a thallus bearing male (an) and female (og, og’) gametangia; and bristle-like projections sheathed at the base (h, h); male gametes, z, z, #9*%. B, ripe odéspore in its rind (7). C, odspore germinating by the formation of swarm-spores (sch). D, swarm-spores of different ages. B-D, 242. (Pringsheim.)— Found with the other species, forming small cushions. produce several new cells, which, growing up around the game- tangium-base and oospore produce a sort of rmd. Thus protected the oospore rests through the winter. In spring the protoplast, by division of its nucleus and the formation of partitions, is transformed into a little mass of cells firmly united with one another but quite distinct from the old cells surrounding them. In this little mass we have, in fact, a new plant entirely different from the sexual plant which produced it. It never produces gametes, but from each cell comes a single swarm-spore which under favorable conditions 'Gam’e-tan’gi-um < Gr. angeion, a vessel. * Spor-an’gi-um < Gr. spora, spore. % O’o-spore < Gr. oan, an egg. THE BROWN ALG 485 grows into a sexual plant like the one already described. Thus in the life-history of Coleochete a sexual form producing gametes, alternates with a form of plant which produces only non-sexual spores. That which bears gametes is termed the gametophyte,1 while the merely spore-bearing one is the sporophyte.2. Hach repre- sents a generation; hence the plants whose life-history is thus di- vided are said to exhibit an alternation of generations. 175. The brown alge (Class Pheophyceez) are charac- terized in general by a brown coloring matter, phycophein,' masking the chlorophyll. They are almost entirely marine. Besides many comparatively simple forms there are some showing a remarkably high development of the vegetative system. In their methods of reproduction the brown alge present rather close parallels to various chlorophyceous types, very rarely, however, exhibiting an alternation of generations. One of the commonest genera is Laminaria (Fig. 316) which includes the familiar leathery ‘‘sea-tangles,”’ ‘‘kelps,”’ or ‘‘Devil’s aprons” often cast upon beaches after a storm. The thallus consists of a flat, more or less leaf-like part (pseudo-leaf) attached to a stalk (pseudo-stem) at the base of which is a hold-fast (pseudo-root), often much branched, which clings to stones or other means of anchorage on the bottom. This thallus which may be yardsin length consists of an exceed- ingly large number of cells among which a considerable differ- entiation may be observed. Thus in the stalk as shown in Fig. 317 we have an outer group of cells forming a sort of rind (r, r) which is comparatively tough and thus protective, while at the same time it serves as a food-making part since the cells are rich in chlorophyll. Those inclesed by the rind, (p, p) form the chief bulk of the stalk, are pale in color, and serve largely for the storage of food-materials elaborated by the outer cells. In the rind occur numerous cavities (g, g) filled with a mucilaginous material. The pseudo-leaf shows a differentiation of cells similar to that of the stalk. For the most part as soon as they are formed the cells lose the power of dividing; but in the region where the pseudo- 1 Gam/et-o-phyte < Gr. gametes, spouse; phyton, plant. 2 Spor’o-phyte < Gr. spora, spore. 3 Phy’co-phw’in < Gr. phycos, seaweed; phaios, brown. 486 LIF E-HISTORIES Fig. 316.—Sea-tangles (Laminaria spp., Sea-tangle Family, Laminartacee). Various forms more or less reduced in size; the larger ones often having the stalk over 1 m. long and the expanded part 2m. (Luerssen.)— These brown, leathery scaweeds are familiar objects along our coasts. leaf joins the stalk there is a cell-mass which retains this power, and from time to time exhibits it in a striking way; that is to say, it forms a new pseudo-leaf at the base of the old one which it eventually casts off, as indicated in the figure. Any mass of connected cells all of which are similar in origin and character is called a éésswe. An undifferentiated tissue, THE RED ALG/® 487 made up of cells still capable of division is termed a meristem, } or is described as meristematic, while a fully differentiated tissue is distinguished as permanent. Laminaria reproduces only by swarm-spores which are formed in sac-like sporangia projecting from the surface of the pseudo-leaf. They are crowded closely, together with a number of curiously shaped protective cells called paraphyses.2. The swarm-spores have a red eye-spot and two flagella which are attached at the side. There are no gametes. A somewhat higher development both of the vegetative and re- productive systems is found in the genus Fucus (Figs. 318, 319) which includes the common “bladder-wracks” of the sea-shore, so called because of the bladder-like floats (/) developed in the thallus. The meristematic tissue is at the tip of the thallus-lobes. A disk-like pseudo-root attaches the thallus to rocks which lie mostly between tides. The pseudo-shoot has forking midribs with flat expansions on either side in which the inflated bladders often appear. There is a rind and an inner, somewhat pith-like tissue much as in Laminaria. The tips of certain branches become swollen (s, Fig. 318) and produce a number of small cavities (conceptacles) each opening by a pore at the surface and lined with numerous paraphyses among which appear either male or female gametangia (lig. 319, a). Within a female gametangium (b,c) eight large, spherical, non-flagellate gametes arise and are pressed out into the surrounding water by swell- ing of the paraphyses. The male gametangia, (d) expelled at the same time emit numerous flagellate gametes (g) which resemble somewhat the swarm-spores of Laminaria. They are attracted in large num- bers to a female gamete, and, attaching themselves to its surface, often cause the sphere to revolve by the energetic movement of their flagella (ce). Directly after fertilization the odspore comes to rest and germinates (f), attaching itself to some rock by projections which form the beginnings of a pseudo-root, while the main part above becomes a meristem for the shoot. No swarm-spores are produced and there is no alternation of generations. 176. The red alge (Class Rhodophycez), the largest and one of the most highly developed groups of seaweeds, are characterized by the presence of a red pigment called phycoerythrin,’ which very generally masks the chlorophyll completely. The carrageen already studied (page 112) belongs to this class. 1 Mer’is-tem < Gr. meristos, divisible. 2 Pa-raph’y-ses < Gr. para, besides; physis, growth. 3 Phy’’co-er’y-thrin < Gr. erythros, red, 488 LIFE-HISTORIES ig! FQ Fig. 317.—Sea-tangle. Transverse section through the outer part of a stalk 2 em. in diameter, °% howing the darker rind (r, r) containing slime-canals (yg, g); and the lighter interior tissue (p, p) which form the greater bulk. (Luerssen.) Fic. 318.—Bladder-wrack (Fucus vesiculosus, Wrack Family, Fucacee). Branch bearing air-bladders (/) and swollen tips (s) containing con- ceptacles. (Luerssen.)—Brown, slimy, tough seaweed, sometimes 1 m. long, growing attached to rocks, ete., between tides along the North Atlantic coast. A comparatively simple type is the thread-weed (Nemalion, Fig. 320). The thallus is small and with slender branehes which grow at the apex but do not show much differentiation among the yegetative cells, Male gametangin (7, sp) are developed at the tips THE RED ALGAL 489 of certain branches, and these emit minute, spherical gametes having no flagella or other means of locomotion. At the tips of other branches female gametes appear, each in the form of a flask- shaped cell with long, slender neck (J, ¢). Fertilization is effected Fic. 319.—Bladder-wrack; a, vertical section through a conceptacle (#2) showing the female gametangia; 5, female gametangium beginning to form its eight gametes; c, the same, beginning to set free its gametes; d, male gametangia (shaded) from which come ciliate gametes like the one (g) shown near by; e, female gamete surrounded by numerous male gametes which cause it to revolve in the water; f, young plant produced directly from the fertilized female gamete. b-f, 482, g, #42. (Thuret.) by fusion of male gametes with the projecting end of a female gamete to which the little spheres have been brought by currents in the water. After fertilization the basal part (J-V, c) gives rise to several branches, each of which finally produces at its tip a spheroidal spore that soon separates, and attaching itself to some support, developes 490 LIFE-HISTORIES into a new Nemalion plant. Spores which are thus the indirect product of fertilization are called carpospores.1 Sexual reproduction in Chondrus (Fig. 118) as also in almost all of the Rhodophycee is by means of carpospores. The process is often much more indirect and complicated than in Nemalion; and, as is the case with Chondrus, the details may be somewhat modified I w/4 IV Fig. 320.—Thread-weed (Nemalion multifidum. Thread-weed Family, Helminthocladiacer). 1, branch bearing male gametangia (sp), and a female gametangium with swollen base aC c) and slender neck (/). II, a female branch after fertilization, the neck (f) withered, and the base beginning to divide for the formation of branches. III-V, later stages in the formation of branches which finally bear spores. All much magnified. (Thuret and Bornet.)—A brownish-red seaweed with branches 5-20 em. long, on exposed rocks at low-water mark, North Atlantic coast. by formation of the ecarpospores within the thallus, as shown in Fig. 321. Non- ara reproduction is accomplished very generally throughout the class by non-motile spores, which are produced usually four in a sporangium. The sporangia may be either at the surface or embedded within the thallus as in Chondrus. The thallus in this genus, as with a large part of the class, exhibits a differentiation of cells similar to that already ! Carp’o-spore < Gr. karpos, fruit. ALG IN GENERAL -491 described in our examples of brown alge, and many of the red seaweeds rival the brown in elaborate forms of thallus simulating remarkably the shoots of higher plants. 177. The seaweed subdivision, alge in general. It is believed by evolutionists that life originated in the sea. Among the alge we generally find that the marine forms are more primitive than their nearest relatives growing in fresh Fia. 321.—Carrageen (see also Trig. 118). A, transverse section through a fruiting branch showing the spore-clusters embedded in the thallus, %°. B, same, #72, showing rind (r), pith-like interior (m), and spore-clusters (s). (Luerssen.) water or in the air. Hence, as being at once the most primi- tive and most typical of the algze, seaweeds may not inappro- priately serve to name the entire group. Over 12,000 species of algee are known. In spite of the great variety of form in the plant-body and in the life-histories of various alge, an alga may generally be recognized as a plant without true roots, stems, or leaves, but containing chlorophyll, although the leaf- green color may be masked by some other pigment. It must not be supposed that the pigments which have suggested names for the several classes of alge are invariably present in these groups, or that mere color is here the basis of classification. The pigments in question happen to be associated very generally with fundamental peculiarities of structure and life-history which give evidence of kinship; hence alge of the same color may as a rule be regarded as akin and thus the pigments afford a convenient though superficial mark for recognizing related forms. 492 LIFE-HISTORIES 178. The fission fungi (Class Schizomycetes). Fungi, broadly defined, are thallus-plants without chlorophyll. In their structure and life-histories they present often note- worthy parallels to what we have already seen in typical alee. Thus, closely similar to the Cyanophycer are the Fission Fungi, otherwise known as Bacteria. A typical ily rf Fia. 322.—Hay bacillus (Bacillus subtilis, Rod-germ Family, Bacteriacec). A, rod-like plants embedded in the film-like gelatinous mass which they produce, *9°. B, plants swimming freely by means of slender lash-like projections, °°. C, plants in the thread condition forming resting spores, #29. (Strasburger.)—These plants cause putrefaction in various liquids such as water in which hay has been soaked. example is the ‘hay bacillus” (Fig. 322) so-called because it thrives in an infusion of hay. About twenty-four hours after such an infusion is made, the liquid gives off an offensive odor and becomes turbid through the presence of myriads of organisms which under a very high power of the microscope appear as short, colorless rods (B). These are scen to be in rapid motion, but it is only by special staining and very great magnification that the exceedingly delicate lash-like projections which cause the movement can be discerned. The ability of these plants to feed upon the organic substances dissolved in the water about them, renders it unnecessary for them to manufacture food for themselves by the aid of sunlight out of inorganic materials; hence like all fungi they can dispense with chlorophyll, and grow as well, often better, in the dark than in the light. A plant which feeds upon dead THE FISSION FUNGI 493 organic material is termed a saprophyte,! and when the chemical changes induced by its activity are offensive the process is putrefaction.2 The motile rods multiply rapidly so long as there is any food available or until the putrid products become so concen- trated as to be harmful to the plant. Then the plants rise to the surface of the liquid, lose their swimming organs, form long threads by remaining attached end to end after fission, and at the same time they secrete a gelatinous covering which binds them all together into a rather firm layer or scum (4d). While in this stage resistent resting spores are formed in many of the cells, by the protoplast becoming round and secreting a new cell-wall (C). If the liquid is allowed to ee *? . Soe . = Sie ois By ha, ale 8% ' Se ecoo” Mae y's Fic. 323.—Milk-souring bacterium (Bacterium acidilactici, Rod-germ Family, Bacteriacee). Plants stained, +9°%. (Migula.)—Causes the souring of milk by converting the milk-sugar into lactic acid. evaporate and the scum to dry it will become more or less powdery, and slight currents of air may then carry away minute bits containing many of these excessively small spores which no mere drying can harm. Myriads of such spores are floating about in the air around us. When a Bacillus spore falls into any putrescible liquid it germinates by elongation of the protoplast and the development of swimming lashes, thus forming a motile rod like that already described. Very similar to Bacilli, both in structure and life-history, are the many forms of the genus Bacterium which differs from Bacillus mainly in lacking swimming organs. Bac- terium acidi lactici (Fig. 323) causes milk to sour by convert- 1Sap’ro-phyte < Gr. sapros, rotten. 2 Putre-fac’tion < L. pulris, rotten; facere, make. 494 LIFE-HISTORIES ing its sugar into lactic acid. Such decomposition, in which the products are not offensive, is distinguished as fermenta- tion.!. Both fermentation and putrefaction are regarded as due to the action of enzyms (comparable to diastase) which are secreted by the active organisms concerned. The tuber- culosis bacterium is another species especially noteworthy as it is the germ of “consumption” in man and other animals, producing various forms of the disease according to the part of the body in which it develops. An organism which thus feeds upon the substance of another living thing is called a parasite;? the erganism which supports it being termed the host. Bacteria capable of producing the discase often oecur abundantly in the sputum of tuberculous patients, and if this dries small bits are readily detached and blown about. A sufficient number drawn into the lungs or getting into the blood of a susceptible host give rise to the disease. Hence the wisdom of isolating tuberculous patients to avoid con- tagion, and the importance of enforcing the regulations of Boards of Health against all spitting in public places. Direct sunlight being soon fatal to the plant in all its stages, affords a most valuable means of preventing infection, and often of effecting a cure by killing the parasite. Nearly all contagious diseases are caused by fission fungi, and to the micro-organisms or “‘microbes”’ of this same class are due almost every sort of putrefaction, fermentation, and decay. The discovery of this important truth has given a new significance to cleanliness, and a knowledge of their life-histories and peculiar properties affords a scientific basis for methods of preventing or regulating the activities of these excessively minute, yet exceedingly powerful agents of change. While some forms of bacteria are a menace to health others are useful in important ways as in the manu- facture of butter and cheese, in the retting of flax and other fibers, and as improving the soil for many farm-plants. The various forms assumed by the cells and colonies of fission fungi may all be closely matehed by forms of blue ' Per’-men-ta’tion < 1. fervere, boil, be agitated. * Par‘a-site << Gr. parasitos, one who eats at another's table, a hanger on; < para, beside; silos, food. THE PIN-MOLD FUNGI 495 alge. The fission fungi, therefore, are regarded as descend- ants of the fission-algze (as the blue alge are sometimes called) which have adopted a saprophytic or parasitic mode of life. All plants which contain chlorophyll and, like the alge, make all their own food by means of sunlight, are termed holophytes;! while those which feed upon organic materials either as saprophytes or parasites are distinguished as hystero- phytes.:. Doubtless in consequence of their change of habit these hysterophytic fission-plants have not only altered their relation to sunlight, but have become more or less reduced in size. Certain species of the group are, so far as known, the smallest of living things. Multiplication solely by fission characterizes the class. 179. The yeast fungi (Class Saccharomycetes). Alco- holic fermentation, or the conversion of a carbohydrate into alcohol and carbonic acid gas, such as takes place in the manufacture of beer and wine and in the raising of bread, is usually accomplished by means of yeast. This consists of unicellular fungi (Fig. 151, a-d). The usual method of reproduction differs from fission in that new cells arise as small protuberances or buds which eventually attain the size of the parent cell. Several resting spores are formed in a single cell (e, f) and these germinate by budding (g, h). There is reason to believe that yeast-plants represent merely a stage in the life-history of more highly developed fungi, which, however, have the power of perpetuating themselves indefinitely in the simple ways described, much as we have seen to be the case with wall-stain alga. Whatever may prove to be their true relationship to other fungi the species of yeast are conveniently placed provisionally in a class by themselves composed of unicellular forms, which reproduce only by budding and the formation of spores by internal cell- division. 180. The pin-mold fungi (Class Zygomycetes). Various fermentations or putrefactions affecting bread, preserves or other food, are often due to so-called “pin-molds” like the Mucor shown in Figs. 324, 325, 326. A spore falling 1 Hol’o-phyte < Gr. holos, whole; phyton, plant. 2 Hys’ter-o-phyte < Gr. hysteros, coming after. 496 LIFE-HISTORIES upon the surface of some nutrient medium germinates by sending out one or more projections (Figs. 325, 3), and these finding abundant food available elongate and branch indef- Fic. 324.—Pin-mold (Mucor Mucedo, Pin-mold Family, Mucoracee). Plant showing the much-branched horizontal mycelium from which arise pin-like vertical hyphz (a, b, c, of different ages) that eventually develop dust-spore-cases at the tip. Somewhat magnified. (Zopf.) | Lj 2 Fic. 325.—Pin-mold. 1, dust-spore-case, viewed as if cut vertically, showing the tip of the vertical hypha (c) projecting into the spore-c the spore-case wall (m); and the numerous dust-spores (sp), 2, same from which the dust-spores have been shed. 3, germinating dust-spore, *°°. (Brefeld.) initely so long as the conditions are favorable. Soon there may be as complex a system of branches as that in Fig. 324. A fungus thread is termed a hypha.t| The mass of hyphe forming the vegetative part of a fungal thallus constitutes 'Hy’pha < Gr. hyphe, « web. THE PIN-MOLD FUNGI 497 a mycelium.' The vegetative hyphe of Mucor form no par- titions, hence we may consider the entire horizontal branch- work shown in Fig. 324 as one cell. Its position marks it as Fic. 326.—Pin-mold. Formation and germination of zygospore. 1, two conjugating branches of the mycelium in contact. 2, separation of the tip of each by cross-partitions, thus forming two “‘conjugating-cells”’ (a, a) and two ‘‘suspensors”’ (b, 6). 3, more advanced stage; warty thickenings have begun to form on the conjugating cells, which, how- ever, are still separate. 4, ripe zygospore (b) between the suspensors (a, a); the conjugating cells now having completely fused. 45, zygo- spore germinating by producing a vertical hypha with dust-spore case at the tip. 1-4, magnified 225 diameters; 5, about 60 diameters. (Brefeld.) the pseudo-root of the plant, and for a while it is the only member developed. Pin-shaped vertical hyphe, which may be called pseudo-stems, arise into the air from the feeding mycelium, and the tip or “head”’ of each being separated by 1 My-ce’li-um < Gr. mykes, a fungus. 498 LIFE-HISTORIES Fic. 327.—Water-mold (Saprolegnia Thureti, Water-mold Family, Saprolegniacee). A, dead fly attacked by water-mold, surrounded by radiating hyphee terminating in swarm-spore-cases, }. 8B, swarm- spore-case in which the spores are forming, #{°. (’, same, discharging swarm-spores. #, female gamatangium containing four female gametes to which comes a projection from the male gametangium that arises as a branch hypha from below the female gametangium, +92. (Thuret, DeBary.)—Water-molds abound upon dead insects, ete., in water. a convex partition, swells into a sporangium which becomes filled with a number of spores. These are soon scattered, and are then ready to produce new mycelia in the manner already described. Such non-sexual spores, serving as do swarm-spores for rapid multiplication, float like dust in the air, and may thus be distinguished as dust-spores. Comparatively large and resistant zygospores are formed by the conjugation of special branches as shown in Fig. 326. The zygospore THE SPORE-SAC FUNGI 499 germinates by forming directly a pseudo-stem which bears a sporan- gium soon filled with dust-spores. The formation of zygospores at once suggests kinship with algie like Spirogyra, and it is believed that molds of the type here shown may have evolved from Chloro- phycez similar to the “pond-scums.” The zygomyceles are fungi which produce zygospores. 181. The water-mold fungi (Class Oomycetes) are typified by a small group closely resembling algze because of their aquatic habits. These water-molds, as they are called, are well represented by species of Saprolegnia (Fig. 327) which grow commonly upon dead insects (A) or succulent plant-fragments decaying in water; or, in some Cases, as parasites upon fish. As with the bread-molds the feeding mycelium is unicellular. Projecting hyphe form ter- minal sporangia from which swarm-spores emerge (B,C). Female gametangia are formed by swellings on certain hyphe, the protoplast becoming transformed into one or more spherical gametes (/). Meanwhile, male gametangia develop either from the same hypha or from hyphe near by, as club-shaped organs which grow toward the female gametangium and send a projection through its wall to the gametes within. After fertilization the female gametes be- come resistant odspores. These eventually are set free and ger- minate by sending out a sporangial hypha in which swarm-spores are developed. In some of the water-molds degeneration of the sexual reproductive organs has gone so far that, although male gametangia are developed no fertilization takes place and oéspores form non-sexually. In extreme cases oospores are formed although no vestige of a male gametangium appears. The life-history of the water-molds is essentially similar to that of other o6mycetes which are parasitic upon land-plants. All of these fungi, to judge from their methods of reproduction are more nearly akin to alge of the type represented by Coleochete than to any other we have studied, although important differences show that the kinship is rather remote. Oomycetes are fungi which produce odspores. 182. The spore-sac fungi (Class Ascomycetes) may be illustrated sufficiently for our purpose by the ‘‘mildews.”’ These, typified by the ‘‘powdery mildew” Erysibe, are parasitic upon the aerial parts of higher land-plants. As shown in Fig. 328 the feeding hyphe creep over the surface of a leaf, and at short intervals send out projections into the - host. These projections by means of which the food is ab- sorbed, are called haustoria. Another peculiarity distinguish- ing these vegetative hyphe from any previously studied is the presence of frequent cross-partitions. Dust-spores are 1 Haus-tor’i-um < L. haustor, a drinker, 500 LIFE-HISTORIES Fic. 328.—Powdery-mildew (Erysibe communis, Powdery-mildew Family, Erystbacew). The surface of a leaf upon which the fungus is parasitic, its horizontal hyphze spreading over the surface and attaching itself by sucking organs; and giving rise also to vertical hyphe producing dust-spores (c), and to fruiting bodies such as a, which contain sac- spore-cases such ase. The fruiting bodies b and d and the hyphe from which they arise belong to another fungus (Cincinnobolus) which is parasitic upon the mildew. Magnified about 450 diameters. (Tu- Jasne.)—Powdery-mildews are all too common parasites upon the foliage of flowering plants both cultivated and wild. I'ie, 329.—Powdery-mildew. Horizontal hyphie (a) from which arise “male”? (b) and ‘female’? (c) gametangia; the latter producing sac- spore-cases enclosed within a protective fruit-body (d, e). (Warming.) THE SPORE-BASE FUNGI 501 formed at the tips of vertical hyphe by the separation of individual cells as shown atc. Each of the dust-spores thus formed is regarded as representing a degenerate spore-case containing but a single spore. Minute sac-like cases contain- ing eight sac-spores are formed within a spherical envelope from the feeding hyphe. What appear to be male and female gametangia arise where two hyphe cross (Fig. 329, a, b, c), the female coming from the lower hypha, the male from the upper. Fertilization has not been ob- served and all sexuality seems to have been lost in these plants; but from what we have called the female cell there are developed several eight-spored sacs or asci,! as they are called, while from the supposed male grow up a number of enveloping branches consisting of many short cells so crowded and joined as to make a complete protective envelope. Fungi related to the mildews and sometimes parasitic upon them, as shown in Fig. 328, b, d, produce very minute dust-spores which are crowded within a case resembling the envelope just described. When the sac-spores are set free under favorable conditions they germinate like the dust- spores. Comparing Erysibe with Coleochete we find some significant resemblances which make it comparatively easy to suppose that fungi of this sort have descended from such algee;—the multicellular creeping branches of the thallus becoming multicellular creeping hyphe; the sporangia, dust-spores; the female gametangium de- veloping into a group of asci, while a neighboring cell, simulating the male gametangium, gives rise to an enveloping rind. These changes are such as might be expected in passing from the aquatic and sun-using mode of life to the aerial and parasitic. Ascospores characterize the Class Ascomycetes. 183. The spore-base fungi (Class Basidiomycetes) are well represented by the mushrooms, although very many widely diverse forms are included among its other members. The common field mushroom (Figs. 119, 330) vegetates by subterranean hyphe feeding upon decaying organic matter in the soil. From this mycelium arise, finally, compact masses of hyphe forming fruit-bodies which soon become differ- entiated into a vertical stalk and a horizontally expanded 1 As’cus < Gr. askos, bag. 502 Fie. LIFE-HISTORIES At) A | Ay \ \ yoy xy 330.—Field Mushroom (sce also Fig. 119). A, mycelium (m) produc- ing young fruit-bodies, }. J, a very young fruit-body cut vertically to show its relation to the mycelium (m). JI, same, a little older, showing the beginnings of gills (). III, TV, V, later stages in which appear the stalk (st), the cap (h) and the veil (v) protecting the gills till they are ripe. (Sachs.) cap. From the under side of the cap hang numerous thin plates, called “gills,” which radiate from the stalk to the margin of the cap. These gills (Fig. 331) bear the spore- producing layer which consists of swollen cell-tips beyond which project club-shaped bodies developing horns, each tipped with a spore. These club-shaped spore-bases are called basidia.' 1 Ba-sid‘i-um < Gr. basis, base. THE MUSHROOM DIVISION 503 Tig. 331.—Field Mushroom. A, vertical section through part of cap (h) at right angles to gills (J), slightly enlarged. 8B, cross-section through a gill, showing the mass of hyphe (¢) continuous with that of the cap, the spore-bearing layer or hymenium (hy), and the layer (sh) from which it developes. C, a part of B (28°), showing the development of dust-spores (s’-s’’’’) upon the tip of projections from swollen hypha- tips or basidia, and other swollen tips (paraphyses, q) which form a large part of the hymenium but do not produce spores. (Sachs.) The possession of basidia characterizes the class, in which, more- over, sporangia are entirely lacking and scarcely a trace of any sexual organ has been found. 184. The mushroom division, fungi in general, are most fittingly named after a type which has departed as far as possible from the holophytic condition. In trying to conceive by what course the higher fungi have evolved, naturalists encounter a peculiar difficulty, for although alge of some sort are presumably the starting point of all, the hysterophytic mode of life soon obliterates almost every peculiarity characterizing 504 LIFE-HISTORIES the vegetative system of the algal ancestor; and as the degeneration proceeds, the reproductive system, whereby kinship is most plainly revealed, loses even the last vestige of sexual organs. Many interest- ing attempts have been made, however, to correlate the various classes of algze and fungi, making allowance for the probable ex- tinction of many forms, and for a considerable evolution of fungi as fungi. For further accounts of these evolutionary interpreta- tions the student must be referred to more special works. The name fungus has been variously restricted by different writers. As here used it is taken in the widest sense as in- cluding all thallophytic hysterophytes, of which about 40,000 species have been described. Fungi are of great economic importance, many of the saprophytic forms being, as we have seen, highly beneficial as agents of decay; while, on the other hand, parasitic forms are often exceedingly harmful. Nearly all the diseases of cultivated plants which so seriously affect the pursuit of agriculture are due to fungal parasites. A scientific study of these, however, has led to the discovery of means of defense which have enabled farmers to increase their crops enor- mously in recent years. 185. The spore-sac lichens (Class Ascolichenes). After long study and careful experimenting in the culture of lichens botanists have reached the strange conclusion that what were at first regarded as individual plants are in reality communities each consisting of a fungus (mostly spore-sac fungi), parasitic upon algee (commonly colonies of Pleuro- coccus), umprisoned by its mycelium. A lichen spore falling among Pleurococcus cells germinates, and the hyphe attach- ing themselves to the alge absorb food materials from them but not generally to an injurious degree. This is shown by the fact that the alge seem to thrive quite as well as before, dividing repeatedly, while the hyphx grow luxuriantly into a mycelium which soon envelopes the algze completely. A well- developed lichen such as “Teeland moss,” for example, shows a compound thallus, in whieh a marked differentiation of parts may be observed (figs. 161, 332-335). At the middle is a layer of loose cottony mycclium (Fig. 335, m) on the borders of which are irregular layers of alga! colonies (g, g) mingled with the hyphee, and, covering all, a firm rind (7, 7) THE SPORE-SAC LICHENS 505 Fie. 332.—Iceland moss (see also Tig. 161). A, tip of thallus-lobe bearing two fruit-patches, called apothecia, and along the edge a number of projections, known as spermagones, which contain dust-spores, }. B, edge of thallus bearing four spermagone-projections, 4°. (Luerssen.) Fig. 333.—Iceland moss. A spermagone-projection, cut vertically to show the cavity (sp) from which dust-spores are discharged. (Luerssen.) consisting entirely of hyphze fused into a uniform tissue. Layers of spore-sacs arise near the tips of the thallus-lobes in Cetraria, and numerous projections inclosing dust-spores ap- pear along the margin. A singular method of reproduction very common among 506 LIFE-HISTORIES lichens is by what are called soredia,! which are little masses of hyphze surrounding a colony of alge. Fig. 336, I shows the soredium of a lichen known as beard-moss (Fig. 336, I) nearly related to the “Iceland moss.” Soredia arise through luxuri- ant development of the inner cottony layer at certain points where they rupture the rind, and force their way to the surface from which they eventually separate. Then being carried by the wind to some favorable spot cach grows into a new com- pound thallus. The formation of soredia makes it possible for lichens to gain a foothold where no other living thing could grow. We find them clinging to the rocks of mountain peaks, Fig. 334.—Iceland moss. Cross-section of apothecium through thallus- lobe, showing the thallus-rind (7, 7), the cottony interior mass hyphze (m, m), among which are green algve, and the layer of spore and paraphyses which form the hymenium (h, h); somewhat dia matic, #2. (Luerssen.) or in arctic regions, or deserts. After a land-slide lichens are the first plants to appear upon the newly uncovered rock, thus beginning that slow accumulation of soil which after many centuries permits the growth of higher plants. For this reason lichens have well been called Nature’s pioneers. Their wonderful power of living upon the air, with what the winds and rain may bring them. is clearly the result of a mutually beneficial co-operation between the alew and the fungi com- posing the thallus. Either alone could not grow where both together thrive. The alew of course are the food-making members of the little community; while the fungus, living upon the organic materials they provide, affords them pro- tection against too intense sunlight, soaks up the rain and dew and retains it sponge-like for a considerable time; and, 'So-re’di-um < Gr. soros, a heap. THE SPORE-SAC LICHENS 507 Fic. 335.—Iceland moss. A small part of the apothecium and thallus shown in Fig. 334, magnified 400 diameters; showing the spore-sacs or asci (a), the paraphyses (p), the compact layer of mycelium (s) from which they arise, the algw (Pleurococcus) known as ‘‘gonidia”’ (g), the cottony mycelium (m), and the compact protective rind (r, 7’). (Luerssen.) Fic. 336, I.—Beard-lichen (Usnea barbata, Beard-lichen Family, Usneacee). Natural size. Granules often appearing on the surface are soredia. (Baillon.)—Grayish or dull yellowish green throughout; often much longer than shown, with a tough central. Common on trees in various parts of the world. finally, keeps them supplied with all the carbon dioxid they need as a raw material for their food. Dissimilar or- ganisms living thus together with benefit to both are called 508 LIFE-HISTORIES symbionts,' and their co-operative mode of life, symbiosis. Plants which grow attached to some support from which they derive no nutriment are termed epiphytes.: Lichens are aérial epiphytes or “air-plants.” Several aerial forms of Chlorophycez besides Pleurococcus, and also a number of Cyanophycee including species of Chroécoccus and Nostoc, serve as the algal symbiont in various lichens. So little has their structure been modified by the symbiosis, they may almost always be referred to forms found living independently. The fungal symbionts, on the other hand, have become so changed in many ways, that usually much une ertainty attends the effort to find their Fig. 336, I1].—Beard-lichen. a, b, a group of cight gonidia among which a hypha is branching. c, a soredium consisting of a single gonidium surrounded by hyphe, viewed as if cut across. d, the same in which the single gonidium has multiplied into several. e, a soredium which contains but a single gonidium, germinating by developing below in contact with the bark of a tree fine hypha-branches which serve as organs of attachment. f, the same, older, showing the multiplication of the gonidia, and the upward growth of the hyphx to form a thallus. (Schwendencer.) near kin among non-symbiotic fungi. They may always be classi- fied, however, as either Ascomycetes or Basidiomycetes, and it is to the former class that the great majority of lichen fungi belong. Ascolichenes are thus symbiotic Ascomycetes. 186. The spore-base lichens (Class Basidiolichenes) include only a few tropical forms of symbiotic Basidiomycetes which may be represented by the mushroom-lichen (Cora pavonia, Vig. 337). This consists of one of the tougher mushrooms associated with a Chrodcoccus, or with another bluish alga, and assumes quite differ- ent shapes according to which alga is present and according as the algal or the fungal symbiont predominates and so determines the form. 187. The lichen subdivision, lichens in general. Li- chens include about 5,000 specics, none of which are of 'Sym-bi-ont, Sym-bi-o’sis < Gr. symbiosis, living together; < syn, together; bios, life. 2 [p’i-phyte < Gr. ep?, upon. THE THALLOPHYTE DIVISION 509 much economic importance. They may be defined as algo- fungal air-plants. Although made up of plants which belong to different classes of Algswe and Fungi, which therefore on theoretical grounds might require to be assigned each to its own class, lichens are in practice more conveniently treated as compound organisms forming an artificial group by them- selves. Fic. 337.—Mushroom-lichen (Cora pavona, Mushroom-lichen Family, Coracer). A, top view of fruit-body, natural size. B, under side showing hymenium (hym). (Strasburger.)—On trees in the tropics. Their dual nature, indeed, doubles the difficulty already encoun- tered in trying to associate different types of fungi with their nearest algal kin. It is of course always desirable to express as well as we can our knowledge of resemblances and our views of kinship; but all this may be done effectively by using names like Ascolichenes and Basidiolichenes (suggestive of relationship between the lichen- fungi and their non-symbiotic kin) and regarding them as forming a series parallel to the series of fungi, much as the fungal series is parallel to the algal. 188. The thallophyte division, lobeworts (Thallophyta) although composed of the humblest members of the vegetable kingdom yet contains, as we have seen, some of man’s best friends, and also some of his most harmful enemies, a knowl- edge of which gained only within recent years has been of incalculable benefit to mankind through improving methods 510 LIPFE-HISTORIES of agriculture and hygiene. Moreover, a peculiar theoretical interest attaches to thallus-plants from the belief that they include representatives of the forms from which all higher living things have evolved. Since the highest differentiation of the plant-body in thallophytes is for the most part a more or less elaborate lobing, the name lobeworts becomes a significant English equivalent for the group. In our survey of thallophytic types, several classes were omitted as involving unnecessary complication. Nevertheless, it is hoped that the student has gained some idea of the evolution of thallo- phytes which may be useful to him in further study. As helping further to a general conception of this multifarious division let us briefly review the main lines of development along which we may reasonably suppose the reproductive and the vegetative system of lobeworts to have been evolved. With ali normal creatures it is as if the controlling purpose of life were the production of well-endowed offspring. Organic evolu- tion seems thus to present a scries of attempts to find the best ways of achieving this purpose under all possible conditions of existence. In the most primitive organisms, typified by Chroécoccus, there is no differentiation into reproductive and vegetative parts, for the entire individual becomes the offspring by fission. Growth in a way prepares for fission, but it may also be regarded as a preliminary part of the reproductive process. Hence we have here what may be called vegetative repreduction in its simplest form. It is a method of propagation admirably adapted to uniformly favorable condi- tions, such as these little water-plants enjoy; and, so long as favor- able conditions prevail, vegetative reproduction is the promptest possible way of taking fullest advantage of them. We therefore sce it retained with more or less modification by organisms which have developed other methods as well, as for example in desmids. When the offspring remain attached, as in Nostoc, colonies arise, and the colony may propagate vegetatively as if it were an individual by dividing into groups of individuals or hormogonia. If the offspring produced by fission remain not only attached but in intimate or- ganic union, the result is not a colony of unicellular individuals but a multicellular individual composed ef subindividual cells. What before was fission has become cell-division. Since the growth of multicellular organisms is entirely by cell-division, all growth may be traced back to the preparatory part of reproduction. We have seen that there is a great difference in the size of vege- table eclls, some plants, such as Mucor, having the body consist of a single cell of relatively enormous size; and there are certain alge, less familiar, with a unicellular body very much larger than this. Such extraordinary development of a single ecll seems not to have THE THALLOPHYTE DIVISION 511 been a very successful type of structure except in cases where some adventitious means of mechanical support could be depended upon, or, as in Mucor, dispensed with because of exceptionally favorable surroundings. But at best the utmost limit of size in a single cell is soon reached, and all large plants and animals consist of innumerable, minute cells. Minuteness of the cell permits as a rule more rapid multiplication, and whether the cells be distinct individuals or the subindividual units of a body-community, minuteness facilitates taking advantage most promptly of all the food available. This principle is strikingly exemplified in bacteria which are at once the smallest organisms known, and the ones ca- pable of most rapid reproduction. Bacteria have been observed to divide at intervals of about a quarter of an hour. At this rate the progeny of one individual would be many millions in a single day. Most plants with a relatively large thallus reproduce vegetatively by setting free minute bits of their protoplasm. Thus most of the aquatic forms, e. g., Ulothrix, Coleochete, Laminaria, and Sapro- legnia convert certain of their protoplasts into swarm-spores resem- bling motile unicellular microbes; while the aérial Zygomycetes, Ascomycetes, and Basidiomycetes produce dust-spores. Both swarm-spores and dust-spores besides being quickly formed and readily set free, have the further advantage from their minuteness of being easily and widely dispersed by currents of water or air, just as was the case with the two halves of the ancestral fission- plants. The larger thallophytes throughout their evolution have thus retained, in their formation of minute non-sexual spores, the most primitive method of reproduction, while vegetating by a single enlarged cell or by a multicellular thallus. An obvious limitation of this primitive, rapid method of repro- duction lies in the fact that it depends upon a continuance of favor- able conditions for its success in perpetuating the species, whereas in nature such conditions are often suspended through periods of adversity. A very simple organism like Chrodcoccus living under fairly uniform conditions can bide its time through seasons of cold and drought and resume its very moderate activity when warmth and moisture return. But the chances of injury are decreased and the power of taking prompt advantage of every favorable oppor- tunity to grow, retained, if at the approach of winter, for example, the tender protoplasts harden by getting rid of superfluous water, become invested by a thicker, firmer wall, and store up what food they can instead of spending it all in immediate growth and re- production. A resting spore such as that of Nostoe thus provides for the future. An improvement upon this simplest type of resting spore is the zygospore in which two protoplasts co-operate to form a single, relatively large cell, well protected and richly stored with food for use at the time of germination. Even in the most primitive cases of co-operative provision for the welfare of offspring, a far-reaching 512 LIFE-HISTORIES advantage probably results from the union of different protoplasts. Much research in recent times warrants the belief that the offspring of two parents is benefited by the interaction of the slightly dif- ferent powers inherited from either side. Invigoration of the off- spring and increased adaptability are often plainly shown. Within specific limits, the beneficial effect of a cross, as the union of gametes from different individuals is called, has been found to be greater as the parents are less alike or have lived under more dissimilar condi- tions. Hence plants which can co-operate in the production of off- spring while living somewhat apart, make the most successful parents. Traveling gametes, as in Ulothrix, enable them to do this. But in order to travel well a gamete must be comparatively small, and when this is true of both gametes as in Ulothrix, the resulting zygote cannot be large or very well provided with food, and is there- fore at a disady antage in becoming a resting zygospore. Here then is an opportunity for a useful division of labor in co-operative repro- duction. Let one of the gametes remain small for traveling, and let the other become as large and as well stored with food as possible, then the result of their union will be a cross-fertilized zygote of superior capabilities. The fact that the most highly developed groups of alge, notably the higher Chlorophycee and the Rhodo- phycew, have adopted this expedient indicates that the experiment has been a great success among thallophytes wherever it could be fairly tried. Along with the possibility of cross-fertilization is apt to go also the possibility of union between gametes from the same individual. This is distinguished as close-fertilization. It is better than no fertilization at all, but seems scarcely more beneficial to off- spring than non-sexual reproduction. Where both gametes are set free, about the best that can be done is the formation of such zygotes as we find in Fucus, where the off- spring receives no further care after fertilization has taken place. When, on the other hand, as in Coleochete, only the male gamete is sct free, the female plant gains the opportunity to act as a nurse to its offspring, giving it additional protection and sometimes food after fertilization until it is well able to take care of itself. This nursing may so affect the development of the offspring that it becomes strikingly different from the form which bears it; then we have an alternation of generations. It is in this new development, which represents the highest achievement of thallophytes in their care of offspring, that we shall find potentialities of the utmost importance for the further development of plants. Fungi, especially non-aquatic forms, have generally degenerated so far as to lose any power of fertilization they may once have had. This may be because in the more or less isolated situations they usually occupy, co-operative reproduction scldom is possible; and another important reason may be that their dependence upon ready made food throughout life makes invigoration and nursing THE LIVERWORTS OR HEPATICS 513 of offspring less important for the welfare of the species than rapid and prolific multiplication. 189. The liverworts or hepatics (Class Hepatice) take their name from a fancied resemblance of the broad-lobed thallus of certain lower forms to the lobed liver of an animal. Fic. 338.—Crystalworts (Riccia spp., Crystalwort Family, Ricciacee). A-C, R. Bischoffii; A, B, clumps of the plant growing on mud, (3) a, male plant; b, female plant. C, male plant, enlarged, showing the male gametangia or antheridia (a). D-H, R. minima. D, plants (3). E, fruiting plant enlarged, top view. F’, a lobe, side view. G, a fruiting lobe, cut vertically through the young ‘‘fruit’’ or sporophyte, still more enlarged. A, spore- eeupe Bue spores. J-M,R.glauca. J, K, plants (3). L, M, lobes, enlarged. N, R. ciliata. N, two plants (3). O, lobes, enlarged. P-S, R. Serer a P, plant (3). Q, fruiting lobes, en- larged, top view. R, same, under side. 5S, lobe cut vertically through the sporophyte. (Bischoff.)—Plants growing in moist places. There are about 3,000 species in the group. The most primitive liverworts belong to the group known as crystal- worts, occurring in all parts of the world and including many species. Some of these grow floating on the surface of still, fresh water and finally come to lie upon the mud when the water subsides in dry seasons. Other forms grow 514 LIFE-HISTORIES more upon moist earth or rocks; in these the thallus shows the broad liver-like lobing especially well, and often appears as a flat rosette (Fig. 338, 4, B). The more aquatic forms have narrow, much-branched, ribbon-like lobes (P, Q, R), and bear a striking resemblance to such algze as carrageen, while the forms with disk-like thallus (J, A), are closely similar to forms of sheath-alge. In both crystalworts and sheath-algze a lobe elongates by the continued division of a single terminal cell, which by its occasional forking gives rise to similar branches. Compare Fig. 314 with Fig. 338, P. One consequence of this continuous terminal growth and branch- ing is that when the older parts die and decay the newer parts are distinct plants which have thus arisen by a sort of vegetative re- production. No swarm-spores are produced, but the thallus often propagates non-sexually by single mature cells in various parts of the thallus dividing like a terminal cell and so producing a tiny bud or brood-body which, separating, becomes a distinct plant. The main structural difference between the alga and the liverwort- thallus is a somewhat more advanced differentiation of the latter. As the cells of Riccia grow older they may give rise on the lower surface to filamentous pseudo-roots and sometimes scale-like or tongue-like pseudo-leaves, while at the upper surface they may form a firm protective layer. Gametangia arise on the upper surface as in Coleochwte but soon become immersed in the thallus through the growth of surrounding cells. Although strictly homologous with the gametangia of Coleochete those of the liverwort are some- what more elaborate in structure. The male gametangium (Tig. 339, A-D) includes a number of cells producing motile gametes each hav- ing two flagella hke the male gametes of Coleochete and differing from them chiefly in having a more slender body. The female gametangium (4, a”) is a flask-shaped multicellular organ containing a single female gamete. A female gametangium thus constructed is distinguished as an archegonium,! the female gamete being called an egg-cell. In some cases both male and female gametangia are borne on the same thallus, that is to say, the thallus is bisexual; while in other cases, a thallus has but one kind of gametangium, making it thus unisecual. In the bisexual plants close-fertilization can doubtless occur; while in the unisexual, only cross-fertilization is possible. Fertilization is effected by a single male gamete, which because of its slender form is able to make its way down the pro- jecting neck of the archegonium to the egg-cell. The zygote be- comes surrounded by a cellulose wall, and through repeated division forms a spherical mass of cells which at first are all much alike. This mass is a rudimentary sporophyte or embryo. The inner ' Ar-che-go/ni-um < Gr. arche, first; gonos, generation. THE LIVERWORTS OR HEPATICS 515 cells each divide into four spores, while the outer cells become some- what thickened to form a protective case or capsule (ig. 338 Q,R, 8). At the same time the basal part of the archegonium grows apace and may become so thickened as to give additional protection to the spores over the winter. When thus developed it is termed a calyp- tra.'. The spores are set free in spring by the breaking down of the coverings about them, and they germinate by producing a row of cells of which the apical one finally develops a thallus like that already described. We have thus in Riccia quite as evident an alternation of generations as we found in Coleochxte, both the gametophyte and the sporophyte being somewhat more highly de- veloped. Fic. 339.—Crystalworts. A-C, Riccia glauca (24%): A, young antheridium; st, stalk. B, same, older. C, same, still older, showing the many cells, in which motile gametes (spermatozoids) are produced. D, ripe an- theridium of R. minima (412); e, outer cells of thallus; J, air-spaces. E, R. ciliata (22°), growing-tip cut vertically to show the terminal cell (s) which by its successive divisions produces all the rest of the plant, the pseudo-leaves (b’—b’’””’) which project from the lower surface of the thallus and hold water for it, and archegonia, very young (a’) and full grown (a’’), ready for fertilization. (Waldner, Kny.) Both generations are still more highly developed in the umbrella- liverwort (Marchantia, Figs. 340-342), a common species growing on the earth in moist localities. The spores germinate much as in Riccia, but the thalli are always bisexual. At first, however, both forms are essentially alike and resemble a brood-lobed Riccia. From the under side arise numerous unicellular pseudo-roots and many seale-like pseudo-leaves. On the upper surface are often formed numerous brood-bodies of the form shown in Fig. 342, which are produced at the bottom of little cups the whole suggesting a minia- ture nest full of eggs. By this peculiar form of vegetative reproduc- tion the gametophyte is rapidly multiplied; for as soon as a brood- 1Ca-lyp’tra < Gr. kalyptra, a veil. LIFE-HISTORIES or pa a oo yeh Fic. 340, I—Umbrella-liverwort | (Marchantia polymorpha, _ Umbrella- liverwort Family, Marchantiacer). Male plant bearing antheridia- carriers (antheridiophores) %. (Atkinson.)—The plant is common on moist earth, rocks, ete., throughout the world. Fic. 340, 1.—Umbrella-liverwort. Top of antheridiophore (%), cut ver- tically to show the cavities containing antheridia. (Atkinson.) body is carried away by some current of rain water and comes to rest in a favorable spot it sends out pseudo-roots from whichever surface happens to be undermost, and begins to grow into a new thallus. After a while organs distinctive of the sex appear near the growing end, and curving upward become differentiated into a cylindrical stalk and an expanded top. In male plants (Fig. 340 I-1V) this top is a lobed disk on the upper side of which are pits, each containmg a multicellular gametangium, from which come slender motile gametes like those of Riccia already described. Archegonia arise also on the top of what is at first a somewhat similar THE LIVERWORTS OR HEPATICS 1 ou “Ni Fic. 340, I1.—Umbrella-liverwort. Antheridium (5°) showing the numer- ous cells within which produce spermatozoids. (Atkinson.) Fig. 340, I1V.—Umbrella-liverwort. Spermatozoids, highly magnified. (Atkinson.) expansion (Fig. 341, I-V), but they come finally to lie underneath through the folding downward of the edges of the lobes. The female gametangia are thus protected by their position, and besides this they are covered by a hanging curtain (Fig. 341, V, p). When the plants are wet with rain or dew the flagellate male gametes are set free and swim or crawl from their elevated home down the stalk and to a female plant; then they climb up its stalk (doubtless aided by numerous hairs thereon) to the archegonia. The fer- tilized ege-cell gives rise to a spheroidal embryo which develops into a sporophyte resembling that of Riccia for a while but finally, by growth of the basal region of the capsule, producing a foot- stalk whose elongation pushes the sporangium through the top of the calyptra (Tig. 341, III). Meanwhile, elongated cells, called elaters 1 (Fig. 341, IV), having elastic, spirally thickened walls are being formed among the spores; and when finally the cap- sule bursts open these elaters, by mechanical movements due to drying, eject the spores and so help to scatter them. The sporo- phyte is fed entirely by the gametophyte and lives as a parasite, the foot or lower end of the stalk serving as an haustorium. Especial interest attaches to the genus Anthoceros (often called horned liverworts from the form of the sporophyte), because these humble plants have preserved structures which help us to under- stand how all the higher plants may have originated. The game- 1E-la’/ter < Gr. elater, a driver. 518 LIFE-HISTORIES Fic. 341, 1—Umbrella-liverwort. Female plant (3), bearing archegonia- carriers (archegoniophores). (Atkinson.) tophyte develops from a spore in much the same way as happens with the other liverworts described. Even more than in Riccia it is like the thallus of Coleochete, notably in possessing but a single chromatophore in each cell, and in having no trace of pseudo-leaves (Fig. 343). The gametangia are completely embedded in the thallus (Fig. 344). The embryo (2) develops a somewhat expanded foot which serves to hold the slender sporophyte in an upright position, and functions also as an organ of absorption. As the sporophyte continues to grow, however, it is plain that seareely more than inorganic materials are taken in; for very soon, above the foot ap- pears an elongating zone of tissue containing much chlorophyll; and this enables the sporophyte to photosynthesize and so, unlike our other liverworts, to be almost self-supporting. If an Anthero- ceros sporophyte should ever develop a root it would no longer need to be even a partial parasite, as now, but could lead an entirely independent existence. The elongating region connecting the cap- sule and the foot is morphologically a shoot, and thus we have in this little plant the beginnings of a differentiation into three mem- bers—sporangium, foot, and shoot. At the center of the shoot and THE TRUE MOSSES 519 Fic. 341, I1.—Umbrella-liverwort. Archigonio- phores (3) bearing ripe ‘fruit’? (sporophytes), the spore-cases of which are seen projecting beyond the curtains which protected them while young. Two of the spore-cases have burst showing the projecting elaters. (At- kinson.) extending into the capsule is a column of somewhat elongated cells, which is called the columella 1 (Fig. 345, c, c). Breathing-pores at the surface permit aération of the inner cells. Hepatice are plants producing archegonia upon a mostly prostrate and thalline gametophyte which may be variously lobed or branched and often resembles a flattened leafy moss, but which generally has well-contrasted upper and lower surfaces; and there 1s a sporangium generally dehiscing longitudinally and discharging its spores by means of intermingled thread-like elaters. There arc about 3,000 species. ) 190. The true mosses (Class Musci). The name ‘moss’ is popularly given to any small, matted plant of soft texture 1 Col-u-mel'la < L. diminutive of columna, a pillar. 520 LIFE-HISTORIES Fic. 341, 11].—Umbrella-liverwort. Top of archigoniophore (4) cut ver- tically to show the stalked sporophytes of different ages: the two inner ones are still within the enlarged wall of the archegonium; the right- hand one has protruded on its stalk leaving the archegonial wall as a sheath (calyptra) at the base of its stalk; while the left-hand one has burst open and is shedding its spores and elaters. (Atkinson.) Via. 341, LV.—Umbrella- liverwort. me, cluster of young spores; sp, spore. An elater. A piece of the same, showing the clastic spring-like spiral thickening within. All highly magnified. (Atkinson.) THE TRUE MOSSES 521 Fic. 341, V.—Umbrella-liverwort. Archegonium (at the left) containing an egg-cell (ec); and (at the right) the same, later, containing a young sporophyte (sp). #42 The neck (n) of the archegonium, and its base (v), are shown in both; as also the protective curtain (p). (Atkinson.) Fic. 342.—Umbrella-liverwort. Thallus (j) showing on the top seven brood-cups containing minute brood-bodies; and below numerous pseudo-roots. (Atkinson.) 522 LIFE-HISTORIES whether it be a seaweed, a lichen, a liverwort, or one of the higher plants. In strictest botanical use it belongs only to about 5,000 species of small green plants which have pseudo- leaves usually arranged spirally on a pseudo-stem, and pro- duce spores in urn-like cases opening mostly by a lid. Fig. 343.—Horned-liverwort) (Anthoceros levis, Horned-liverwort Family, Anthocerotacee). Plant (4) with three ‘fruits’? (sporophytes). (Luers- sen.)—Rather common in moist soil. Fig. 344.—Horned-liverwort. A, branched thallus. 8B, thallus (27) ou vertically to show the antheridia (an), the pseudo-roots (w), and ¢ colony of Nostoc (k) which sometimes lives in the interior of this ple th Ce vertical section through tip of thallus (3°) showing beginnings of archegonia (ar). D, section through older part of thallus (*5°), show- ing a fertilized archegonium in which the egg-cell has begun to divide. FE, embryo of sporophyte showing shoot-part above and foot below. (Hofmeister.) True mosses resemble liverworts except in having a mostly erect gametophyle with pseudo-leaves spirally disposed about a pseudo- slem which supports a sporangium dehiscing by a lid and lacking ela- fers. These peculiarities are shown in the peat moss (Sphagnum, Pigs. 227, 346-349) and the cord moss (Funaria, Figs. 350-356). The spores of Sphagnum (Fig. 346) germinate in water by send- ing out a branched thread which resembles a filamentous alga. Sooner or later this thread gives rise at several points to apical cells each of which by its frequent oblique divisions produces a pseudo- stem: with pseudo-leaves. If, however, the spore falls upon moist earth, its germination is more like such a liverwort as Anthoceros or Marchantia, for the initial thread soon develops into a. flat- lobed thallus, producing slender pseudo-roots below, and vertical THE TRUE MOSSES 523 up ae lobes Ea Fic. 345.—Horned-liverwort. Young sporophyte (sg, sg) showing the be- ginnings of a columella (c, c) and spores (s). L, ZL, calyptra, 392. (Hofmeister.) Fic. 346.—Peat moss (Sphagnum acutifolium, Peat moss Family, Sphagna- cee). A, spore, highly magnified. C, spore (s) germinating in water producing a green branched thread or protonema (n, n’) from which buds (pr, pr) arise and produce gametophytes. (Schimper.)—Plant common in bogs. Fic. 347. — Peat moss. Flat pro- tonema (pr, pr) produced on moist earth, giv- ing rise to a gametophyte (7m) and pseudo-roots (w),43¢. (Schimp- er.) LIFE-HISTORIES . 348.—Peat mosses. «4, part of a gametophyte, enlarged, showing male branches (a, a, a, a) and female branches (b, b). B, part of a leaf (S. cymbifolium), °°°, showing the net-work of green cells surrounding the large ones which fill with water or air. C, vertical section through a small piece of leaf GS. cuspidatum) showing the small and the large perforated cells, #29. D, cross-section through outer part of stem GS. cymbifolium) highly magnified. 2, male branch of S. acutifolium, with a vegetative branch at the base, 37. /’, same, with many pseudo- leaves removed to show the male gametangia (antheridia), °°. G, an opened and empty antheridium, #%°. H, five cells containing young spermatozoids, “7°. J, such a ecll nearly ripe, °°. A, spermatozoid, no. f, ripe ‘fruit’ (sporophyte) with remains of the archegonium at its base borne on a stalk continuing the axis of the pseudo-stem which bears pseudo-leaves at its base; magnified. (Sehimper.) THE TRUE MOSSES 525 moss-branches above (Fig. 347). In either case these vertical pseudo- leafy shoots are homologous with the ascending branches of Mar- chantia; but as seen in Tig. 348 they are much more elaborately constructed. At the surface of the stem are developed usually several layers of large cells with very thin walls which are kept from collapsing by ridge-like thickenings, and communicate with one another and with the exterior by pores (D) of considerable size. These cells soon lose their protoplasm and then form a sponge-like Fic. 349.—Peat mosses. A, tip of female branch of S. acutifolium, cut vertically to show the archegonia (ar), protective leaves (ch) still young, and older ones (y) acting like bud-scales. B, young ‘‘fruit,”’ cut vertically to show the sporophyte of which the foot (sg’) is fixed in the head (v) of the stalk or pseudopodium (ps), and the spore-case (sg) ts still enveloped by the calyptra (c) bearing above the old neck (ar) of the archegonium. C, ripe sporophyte of S. squarrosum, showing its lid (d) and spore-case (sg) emerged from the torn calyptra (c) and borne upon a pseudopodium pushing it beyond the formerly protecting pseudo-leaves (ch). All magnified. (Schimper.) or wick-like envelope which draws water from below by capillarity, and stores it ready for use. The pseudo-stem is strengthened by a uniform thickening of the walls of an inner cylinder of cells. The pseudo-leaves are made up chiefly of large, thin-walled cells (B) like the outer cells of the pseudo-stem, similarly reinforced by ridges and similarly perforated. They supply water to a net-work of small cells containing numerous chromatophores in which the work of photosynthesis is carried on. Vegetative reproduction so far as known takes place only through the separation of branches 526 LIFE-HISTORIES by decay of the older part. Male gametangia (/’) are borne on the side of special branches which may be recognized as having their leaves more crowded and often reddish (A and £). The numerous male gametes (/() are more elongated and more spiral than those of Marchantia, but are otherwise similar. Archegonia are produced at the tip of short branches surrounded by comparatively large leaves (Fig. 349, 4). After the female gamete has been fertilized, the axis of the branch elongates into a stalk bearing at its tip the enlarging sporophyte enveloped in the calyptra (B, C’). The sporo- phyte is differentiated into a short, thick foot (sg’) and a capsule in which there is a central mass of large air-filled cells surmounted by Fie. 350.—Cord-moss (Funaria hygrometrica, Cord-moss Family, Punaria- cow). A, germinating spore (442) showing a sap-filled cavity or vacuole (v) a pseudo-root (w, w), and the old outer spore-wall (s). B, further development of the thread (protonema) which comes from the spore, showing the main thread (h) and side branches from one of which ()) is growing a bud (A) destined to form a pseudo-stem and pseudo- leaves, and already sending out a pseudo-root (w), 72. (Sachs.) a hollow dome-like mass of spores, and the whole inclosed in a firm wall of small, hardened eclls. A horizontal ring of these becomes finally so brittle as to render the top of the capsule separable like a lid (Cd). As the capsule enlarges, the calyptra (c) is ruptured, and as the spore-case dries its form changes perceptibly from spherical to subeylindrical but without elongation. The result is that the inner air-filled cells below the spore-mass are so much compressed, that a degree of tension is soon reached sufficient to blow off the hd with a perceptible report and seatter the spores to a distance of several inches. Elaters are thus unnecessary. In Punaria (Figs. 350-356) the spores when germinating (Fig. 350) produce a much-branched thread which makes a bright green, felt- like layer on moist earth. From this thread at many places arise directly vertical pseudo-shoots each consisting of an axis bearing THE TRUE MOSSES 527 Fra. 351.—Cord-moss. Tip of a male gametophyte cut vertically to show the male gametangia (antheridia) of various ages from young (a) to almost full-grown (b); also paraphyse (c), protective pseudo-leaves (d) and foliage pseudo-leaves (e), #2°. (Sachs.) Fic. 352.—Cord-moss. conamunicating with the internal air-spaces of the cortex. ach opening is guarded by two special cells which might be likened to lips. It is by means of these breathing pores that the interior tissues are acrated. Whereas in the sporophyte of Sphagnum we have a very simple sporangium from which there is differentiated a small foot and the merest hint of a short connecting stem; in Fu- naria we find a long slender stalk, homologous with the foot, bearing a capsule made up of the sporangium partly inclosed by an urn-like mass of tissue which we may call the shoot. Funaria represents about as high development of the sporophyte as moss plants have ever attained. 191. The bryophyte division, mossworts (Bryophyta) comprises only the two classes liverworts (Hepatic) and true mosses (Musci) which in general are often called moss- worts. Mossworts show us possibly how green earth-plants first stood upright. The occasion for their vertical development may have arisen when certain flat alge more or less like Coleochete, became stranded and had to form spore-cases as best they could before the mud completely dried. If some of them were able to make a small globular capsule this might be fed entirely by the thallus, but being immersed within it could not ordinarily scatter the spores very far. Their descendants perhaps give us Riccia. Others we may suppose, hit upon the plan of elongating the capsule upward, giving it some chlorophyll to utilize the sunshine, and thus enable it to make more spores and scatter them farther—all with much less dependence upon the slender resources of the little nurse. The result would be a liverwort of the Anthoecros type which solves the problem of up- hifting its spores in the simplest way. Various more or less com- 1 Pros-en’chy-ma < Gr. pros, before; en, in; cheo, pour. * Par-en’chy-ma < Gr. para, beside. A term applied by the earlier anatomnists to the raain tissue of such organs as the lings which they supposed was formed of material poured in beside the vessels and nerves that had been “ poured in” before. § [ep-i-der’mis < Gr. ep?, upon, ¢. e., outer; derma, skin. 1 Cor’tex < L. corlex, rind or bark. °Sto’ma < Gr. stoma, a mouth. BRYOPHYTE DIVISION, MOSSWORTS 5381 plicated expedients were adopted by plants akin, and the outcome 18 seen in such liverworts as Marchantia where small capsules are made to hang from the branches of vertical thallus-lobes, or in mosses like Sphagnum where a similar though ercet capsule is borne on an even more elaborately developed vertical branch of the nurse- plant, which may live for many years. The most complicated ways of securing elevation are found in the mosses typified by Funaria, where both the nurse-plant and the spore-plant develop vertically as far as they can—the latter, as it were, standing upon the shoulders of the former—and by photosynthesis making food for the spores. But the utmost height attained by these methods is only a few inches; the foundation is weak. Growth which has to be accom- plished during a short season of moisture or by improving brief periods of wet weather, must naturally for the most part be limited to rather soft tissue and smali organs. Mosses often grow crowded together like Sphagnum and thereby give mutual support and store a supply of water fer use in common; but although axes of considerable height may be buiit in this way, the offspring is not much benefited, for the crowded tops of the axes form virtually a new surface above which is the only height effective for scattering the spores. It is plain that effectiveness is not always favored by complexity. The view suggested above that mossworts have evolved directly from alge akin to Coleochete, although regarded as probable by many botanists, receives no support from the study of fossil plants; and is by no means the only view consistent with what is known of the plants of to-day. Thus, it is quite possible that our mossworts may be the more or less simplified descendants of larger plants widely different from any we know, which themselves were de- scended from seaweeds very unlike Colechete and of which we have now no trace. Nota few facts point to this conclusion; but the truth is we are much at.a loss as to what to believe regarding the origin of mossworts, and the question seems likely to remain long a puzzle. Meanwhile, the hypothesis of direct algal origin may help us to imagine something of the nature of the problems which had to be faced by the earliest Jand-plants, whatever these plants may have been; and may suggest, at least by analogy, something of the means that may have proved most. effective. When we remember that Bryophytes have had to depend almost entirely upon superficial moisture it is not a little remarkable how much they have been able to accomplish for the welfare of their offspring. In spite of serious difficulties attending the use on land of reproductive arrangements adapted to aquatic life, these little plants very commonly achieve the benefits of cross-fertilization, and of a considerable period of nursing for their young. All this is made possible by the formation of archegonia which not only pro- tect. the protoplast of the egg, but by further development shield the young spore-plant all through its time of special tenderness. 532 LIFE-HISTORIES Finally, in a considerable varicty of ways means are provided for scattering the spores as far as possible and under the most favorable conditions for giving the new plants a good fair start. Bryophyta are distinguished by having archegonia on lobed or pseudo- leafy gametophytes which bear sporophytes lacking true roots, stems, and leaves. Fic. 357.—Adder-tongue, A, and grape-fern, B (Ophioglossum vulgatum and Botrychium Lunaria, Adder-tongue Family, Ophioglossacec). Sporophytes showing roots (w), stem (sé), leaf-stalk (bs), point (x) at which leaves branch to form a foliage-blade (6b) and a spore-bearing division (f). Two-thirds natural size. (Sachs.) but widely distributed in mostly open ground. Not very common 192. The ferns (Class Filicine). Our most primitive ferns are represented by adder-tongues (Ophioglossum) and grape-ferns (Botrychium, Fig. 357). Unfortunately their life-histories are not yet fully known owing to peculiar difficulties in tracing the germination of the spores. The gametophyte is subterranean (Mig. 358) and at least when mature it is saprophytic. Exeept for its lack of chlorophyll it is not a little like the gametophyte of Riecia. The gametophyte of THE FERNS 533 certain ferns closely related to the above more nearly resembles that of Anthoceros, and is holophytic, as we may suppose to have been the case with the original fern-ancestor. When we compare the sporophytes of an adder-tongue and a horned liverwort, how- ever, so many striking differences appear, that it may at first seem hopeless to think of homologizing the parts. Indeed, we have in ferns true leaves, stems, and roots, no trace of which appear in any liverwort. But we have sporangia in both, and in the growing zone of Anthoceros we have a cylindrical meristematic organ suggesting possibilities of much further differentiation. If the sporangium of s Fic. 358.—Grape-fern. A, gametophyte (prothallus) cut vertically to show the antheridia (an), the archegonia (ac), and the pseudo-roots (w), 50 B, lower part of a young sporophyte dug up in September, cut vertically to show the stem (st) and leaves (b, b’, b”), #9. _(Hofmeister.) Fic. 359.—Adder-tongue. Upper part of spore-bearing division of leaf (%), cut vertically to show the tip (s), the spore-cavities (sp), the places (7) where a slit is formed to free the spores, and the woody strands or fibro- vascular bundles (g) which strengthen and conduct sap. (Sachs.) Anthoceros were enlarged and instead of elaters produced sterile tissue between groups of spores forming two rows on either side of the columella, the resulting organ would be a flat spike of sporangia like that of Ophioglossum (Fig. 359). What may have happened is that in very ancient times, before the age when coal plants flour- ished, a liverwort something like an Anthoceros did evolve a root from the lower end of its growing zone, which made possible an expansion of the green tissue above, while this in turn helped to bring about the formation of two rows of globular sporangia making a flat cluster as already described. Such an expanded member 534 LIFE-HISTORIES bearing sporangia would be a spore-sac-leaf, while the cylindrical elongating zone from which it arose would now be a true stem. Here would be about as simple a fern as we can imagine; but it would have all the essential features, and it is not inconceivable that higher forms might have been evolved from it. Suppose, for instance, that the sac-leaf member forked into two branches, and let one of them be expanded so as to secure as much sunlight as possible and be devoted exclusively to ee while the other branch instead of doing much food-making was narrower and developed as many spores as possible from food that the expanded branch furnished. Suppose further that the stem lived on from year to year, sending new roots into the earth and new leaves into the air, then our plant would have become like an adder-tongue fern. The striking differences between liverworts and ferns of any kind have so impressed not a few botanists as to have made them doubt the likelihood of ferns having originated in the manner above suggested; and this doubt has gained strength from the fact that the most ancient fossil ferns are of highly complex organization, being often tree-like in form, and so even less like liverworts than the presumably degenerate ferns with which we are most familiar to-day. Moreover, if modern liverworts are also to be regarded as degenerate plants—a view, as we have seen, for which there is some evidence—the gap which separates them from ferns is even wider. It may well be true that ferns evolved directly from sea- weeds in which a clearly marked alternation of generations had developed as in certain rather highly organized red alge living to-day. On this supposition, however, we are still left with the difficulty of imagining the stages through which a seaweed could pass in fitting itself for life on land as a tree. Here fossils cannot help us, for we have none at all intermediate between seaweeds and ferns. Since, however, there are undoubted fundamental re- semblances between a Coleochste, an Anthoceros, and an Ophio- glossum, these may offer at least a possible cluc as to how the great changes in question may have taken place. Grape-ferns would be readily derivable from adder-tongues by further branching of the two leaf branches, which in the fertile or sporangial segment might result in each sporangium being borne on a little stalk or branchlet of its own. We may well imagine that wonderful possibilities of development lay before such a type as this as soon as it established itself on the edges of swamps or on land where food and moisture abounded. It could then afford to delay the production of spores until it had built a thick, tall stem, by means of leaves made larger and larger year after vear and devoted entirely to making food so that a surplus might be stored in the stem. Vinally, a very large number of sporangia might be produced upon much-branched spore-sac-leaves; and these, held high in the air, could scatter their spores most effectively. 5 THE FERNS 53 We know that during the coal age many tree-ferns like the Pecopteris shown in Fig. 277 (page 299), apparently near of kin to the adder-tongues, produced stout trunks bearing a crown of ample leaves nearly twenty meters above the ground. Fic. 360.—Tree-Ferns and Herbaceous Ferns. (Baillon.) At the present day tree-ferns such as the one shown in Fig. 360 abound in moist, warm regions, although the ferns most common in northern lands are more like the smaller ones shown in the same illustration. Thus it would appear . that a certain amount of degeneration has attended the adaptation of ferns to the more stringent conditions of cold 536 LIFE-HISTORIES a Fig. 361.—Male-fern (see also Fig. 170). a, b, germination of spores show- 60 ing formation of young gametophytes (prothallia), %. (Luerssen.) Fig. 362.—Male-fern. A, prothallus, lower side, showing archegonia (ar), antheridia (an), and pseudo-roots (rh), {. B, same, after production of young sporophyte, showing first leaf ()) and first root (w). (Schenck.) or dry climates. One of our best developed northern ferns is the Aspidium already studied (Fig. 170, page 179). As shown in Tigs. 361, 362, the spore in germinating produces first a row of cells, the terminal one of which soon divides in such a way as to produce a flat, heart-shaped thallus, which is rich in chlorophyll and sends out from the under side of the older part a number of pseudo-roots. By means of these the rear end is firmly attached to the earth while the lobed end slightly ascends. Finally on the lower surface appear archegonia near the tip, and male gametangia toward the base. The latter and their motile gametes are of the form shown in Fig. 363. The gametes, it will be noticed, are somewhat more highly developed than any found among the Bryophyta. That is to say, the spiral is larger and the flagella are more numerous. The archegonia, which are like the one shown in Fig. 364, differ but little from the others already studied. After fertilization the egg-cell divides into four (Fig. 365, 4). The upper- most of these, by its further growth and division produces the foot (f) the function of which is to act temporarily as an haustorium for the embryo-sporophyte, and to push it out of the gametophyte and on to the earth. One of the lateral cells develops into the first root (w) while the opposite one becomes the growing point of the stem, and THE FERNS 537 the lowest cell gives rise to the first leaf. A later stage in the de- velopment of these parts is shown in Fig. 365, B. Covering the growing tip of the root, somewhat as a thimble covers a finger tip, Is a protective organ termed the root- -cap. Such a thimble- like cover- ing continually renewed by the meristem which it protects is char- acteristic of true roots. Root-hairs for absorption are soon devel- oped. The leaf (Figs. 365, B, 362, B) soon differentiates into petiole and blade, and curves so as to dr: ag the tender leaf-tip uP out of the ground. An extreme curving of this nature performed by every Fic. 363.—Fern Antheridium (Pteris sp., Polypody Family, Polypodiacee), sso, (Luerssen.) Fic. 364, —Fern Archegonium (Osmunda sp., Royal-fern Family, Osmunda- cee). A, first stage viewed from above, *%. B, same, cut vertically to show the central cell (c) from which the eee is formed, and the cells (h) which give rise to the neck, 47%. C—-E, older stages, showing canal cells (he, bc). F, neck with mouth closed. G, same, top view. H, same, mouth open. J, same as # but with egg-cell (e) ready for fertilization. (Luerssen.) branch of the developing leaves gives us the familiar crozier-like vernation characteristic of ferns. In the axis of the stem soon ap- pears a central cylinder of prosenchyma which developing also in the root and the leaf serves as a channel for conducting solutions absorbed by the root to the green food-making parts of the leaf, and likewise dissolved nutrients from the leaves to the stem and the root where they may be used in growth or stored as a reserve. As the stem grows larger, and leaves and roots become more numer- ous, its central cylinder becomes a hollow cylindrical net-work of broad flat meshes (Fig. 366), giving off slender branches to the 538 LIFE-HISTORIES Fic. 365.—Fern Embryo (Pleris sp.). A, embryo removed from archegon- ium and cut vertically to show the first dividing wall (I, I) and the walls at right angles to this (II, II) whereby the tvalined egg-cell was divided into quadrants of which one (f) by further cell-division and growth becomes the foot, another (s) the stem, another (b) the first leaf, and another (w) the root. £8, embryo still further ee but still attached to the prothallus (pr), cut vertically to show the foot (/) embedded in the archegonium (aw), the root (w) with its tip protected by a root-cap, the stem (s) and the incurved leaf (b). Magnified. (Hofmeister.) leaves and roots. When a leaf falls off it leaves a sear upon which one may see clearly traces of these slender branches which went into the petiole. In the trunk of a tree-fern (lig. 367) the prosenchyma is par- ticularly well-developed and shows plainly a differentiation of tissues which is characteristic of all plants higher than bryophytes. Sach strand is here found to contain thick-walled woody fibers (FB) and larger cells (VS) called vessels which have thin walls variously strengthened by ridges. These vessels correspond to the ‘‘pores” found in the wood of oak and other trees we have already studied. Such strands are called fibrovascular? bundles, and the plants cr parts containing them are said to be vascular. The ultimate branches of the framework of a leaf are often nothing but single vessels. Be- sides the woody and the vascular tissues, which serve mainly for conducting fluids, ferns and higher plants often develop strands or layers of hardened, thick-walled cells whose funetion is mainly to give strength or afford protection. Such tissue is termed scleren- chyma? im general, or sclerotic parenchyma or prosenchyma in particular. An outer layer of the cortex as at (/’L) often becomes sclerotic and thus contributes much additional strength to a co- lumnar organ. The parenchyma of a fern-stem serves very largely for the storage of reserve food in the form of stareh. T'rom the epidermis of various parts may arise hair-like or scale-like out- erowths which serve mainly to protect organs that are very young or especially need to be covered. Whereas in multicellular plants 'Ti/bro-vas’cu-lar << L. fibra, a fiber; vasculum, a small vessel, * Scler-en’chy-ma < Gr. skleros, hard, THE FE RNS 539 Fic. 366.—Fern Stems (Aspidium spp.). A, underground stem (rhizome) of A. Pilix-mas with rind removed to show the net-work of fibrovascular bundles. 8B, one mesh of this net-work enlarged to show the branches which enter a leaf to form its framework. C, cross-section of a rhizome (A. corieceum) slightly enlarged to show the cylindrical fibrovascular system formed of two main strands, the upper (0) smaller than the lower (n), and the finer branches of these which enter the leaves. D, the fibrovascular cylinder of the same, removed and laid out flat after splitting the lower strand (uw, uw) in halves, leaving the upper strand (0) in the middle unbroken, as also the finer strands (b, b, b, b) which enter leaves and roots, and the larger strands (x, z, x, x, x) which enter branches of the stem. (Sachs, Mettenius.) of simpler structure it was sufficient to distinguish merely different tissues, in the higher plants the differentiation has progressed so far that fisswe systems must be recognized. Thus we have a tegu- mentary system consisting of the epidermis and its outgrowths, a vascular system comprising the vascular bundles, and a fundamental system consisting mainly of parenchyma and including meristem, the green cells accessible to light, and the pith-like internal parts in which food is stored. The stem of an Aspidium (Fig. 170) as of nearly all our native ferns, remains mostly underground as a more or less horizontal rhizome.