(903 Cornell Mniversity Library BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Henry W. Sage 1891 JAAIZ 2&9 2 a.[ dos. | arv1908: ati Found iil cornell University Library io ii0itibun 3 1924 031 488 5 [ olin,anx Te TEE ~ The date shows when this volume was taken. as NOV 1 '29y Th ao Ue — g sVoT tT Ax’OT 27 Mrs 17 Ap’08 a4. Vo eeyes” 110 O09 11 Ap’19- ASys 3 1911 “3 Aer ke REY Bye OCT R 19 2 JUNIGIE g suits & WAY(Sit dc "3 1917: 1920 All books not in use for instruction or re- | search are limited to all borrowers, = Volumes of periodi-~ cals and of pamphlets . comprise so many sub- * jects, that they areheld\ . in the library as much as possible. For spe- cial purposes they are given out fora limited _ time. : Graduates and sen- iors are allowed five volumes for twoweeks. Other students may ‘have two vols, from the circulating library for two weeks. ’ ; Books not needed | duritg recess periods - shoul baretaiied to. the library, or arrange- ' ments made for their return during borrow- er’s absence, if wanted. | Books needed by giere than one person ~@9¢ held on the reserve {Books of special . agine and gift books, when the giver wishes >ft; are not allowed to <€irculate. = Fronvisrizce. —A Shade Plant, Jack-in-the-Pulgit FOUNDATIONS OF BOTANY BY JOSEPH Y. BERGEN, A.M. InstTRUCTOR IN BioLocy, ENcLisH H1cH ScHooL, Boston BOSTON, U.S.A. GINN & COMPANY, PUBLISHERS The Atheneum Press 1904 4\-3) Dt NAAB YS 4, CoPYRIGHT, 1901, BY JOSEPH Y. BERGEN ALL RIGHTS RESERVED af tf PREFACE Tus book is written upon the same plan as the author’s Elements of Botany. A few chapters stand here but little altered from the former work, but most of them have been rewritten and considerably enlarged, and many new ones have been added. The principal changes in the book as a whole are these: 1. Most of the discussion of ecological topics is put by itself, in Part IT. 2. The amount of laboratory work on the anatomy and physiology of seed-plants is considerably increased and addi- tional experiments are introduced. 3. The treatment of spore-plants is greatly extended, so as to include laboratory work on the most important groups. 4. The meagre Flora which accompanied the earlier book has been replaced by one which contains fairly full descrip- tions of nearly seven hundred species of plants. Most of these are wild, but a considerable number of cultivated species have been included, mainly for the convenience of schools in large cities. Ample material is offered for a year’s course, four or five periods per week. The author is well aware that most schools devote but half a year to botany, but the tendency sets strongly toward allowing more time for this subject. Even in schools where the minimum time allowance is devoted to botany, there is a distinct advantage in being provided with a book which allows the teacher considerable option as regards the kind and amount of work which he shall offer to his classes. im iv PREFACE Suggestions are made in the teacher’s Handbook, which accompanies this volume, in regard to shaping half-year courses. The latest authorities in the various departments of botany have been consulted on all doubtful points, and the attempt has been to make the book scientifically accurate throughout, yet not unduly difficult. Most of the illustrations have been redrawn from those in standard German works of an advanced character, or drawn from nature or from photographs, expressly for. this book. Besides the sources of drawings acknowledged in the author’s Elements, many cuts have been taken from the botanies of Frank, Prantl, Detmer, Murray, and Bennett and Murray, as well as from Schimper’s Pflanzengeographie. Of the drawings from nature or from photographs, some figures, and Plates I, VII, and VIII, are by Mr. Edmund Garrett of Boston; several figures, the Frontispiece, and Plates II, IV, X, XI, are by Mr. Bruce Horsfall of New York ; several figures are by Mr. F. Schuyler Mathews of Boston; a large number of figures and Plate V are by Mr. E. N. Fischer of Boston; several figures are by Mr. E. R. Kingsbury of Boston and Dr. J. W. Folsom of the University of Illinois. Thanks for the use of photographs are due to Mr. H. G. Peabody of Boston (Fig. 234), to Mr. J. H. White of Boston (Figs. 32, 75, 222), to Professor Conway MacMillan of the Uni- versity of Minnesota (Frontispiece), and to Professor F. V. Coville of Washington (Plate VII). Figs. 28 and 275 are taken by permission from the Primer of Forestry, issued by the Division of Forestry, U. S. Department of Agriculture. Figs. 263, 264, 276 are copied by permission from Professor W. J. Beal’s Seed Dispersal, and Figs. 226, 229, 233 from Professor ‘W. M. Davis’s Physical Geography. Fig. 269 is from a photo- graph by Professor C. F. Millspaugh of Chicago. Plate IV is from a photograph by Dr. H. J. Webber. / PREFACE ¥ Most of the redrawn illustrations (not microscopical) from various European sources are by Mr. Fischer. Most of the microscopical ones (and a number of figures from nature) are by Dr. J. W. Folsom of the University of Illinois, and many of both classes are by Mr. Mathews. Thanks are due to Professor J. M. Holzinger of the Winona (Minn.) State Normal School, to Professor L. Murbach of the Detroit High School, and to Mr. I. 8. Cutter of Lincoln, Nebraska, for their many discriminating criticisms of the proof of Parts I and IJ. Mr. Samuel F. Tower of the Boston English High School, Professor Charles V. Piper of the Washington State Agricultural College, and Dr. Rodney H. True, Lecturer on Botany at Harvard University, have all read the whole or large portions of Part I and given valuable suggestions. Professor W. F. Ganong, of Smith College, has read and criticised Part II. The chapters on spore-plants, excepting a small amount of matter retained from the Elements of Botany, are entirely the work of Mr. A. B. Seymour of the Cryptogamic Herbarium of Harvard University. _ The author has attempted to steer a middle course between the advocates of the out-of-door school and of the histological school of botany teaching. He has endeavored never to use a technical term where he could dispense with it, and on the othér hand, not to become inexact by shunning necessary terms. In deciding questions of this sort, a priori reasoning is of little value-; one must ascertain by repeated trials how much of a technical vocabulary the average beginner in botany can profitably master. The teacher who has discovered that not one of the boys in a division of thirty-six pupils knows that his own desk-top is of cherry wood may well hesitate’ about beginning his botany teaching with a discourse on cen- trospheres and karyokinesis. It has been assumed throughout this book that, other things being equal, the knowledge is of vi PREFACE most worth which touches the pupil’s daily life at the most points, and therefore best enables him to understand his own environment. On the other hand, the author has no sympathy with those who decry the use of apparatus in botany teaching in secondary schools and who would confine the work of their pupils mainly within the limits of what can be seen with the unaided eye. If the compound microscope plainly reveals things shown only imperfectly by a magnifier and not seen at all with the naked eye,-——- use the microscope! If iodine solution or other easily prepared reagents make evident the existence of structures or substances not to be detected with- out them, — then use the reagents! No one thinks of deny- ing a boy the use of a spyglass or a compass for his tramps afield or his outings in a boat because he has not studied physics. No one would refuse to let an intelligent boy or girl use a camera because the would-be photographer had not mastered the chemical reactions that follow upon the expo- sure of a sensitized plate. Yet it is equally illogical to defer some of the most fascinating portions of botanical study until the college course, to which most never attain. When the university professor tells the teacher that he ought not to employ the ordinary appliances of elementary biological inves- tigation in the school laboratory because the pupils cannot intelligently use them, the teacher is forced to reply that the professor himself cannot intelligently discuss a subject of which he has no personal knowledge. The pupils are deeply interested; they prove by their drawings and their recita- tions that they have seen a good way into plant structures and plant functions; then why not let them study botany in earnest ? J. Y. B. CampBrinex, January, 1901. CONTENTS Part I STRUCTURE, FUNCTIONS, AND CLASSIFICATION OF PLANTS CHAPTER I PAGES Tue SEED AND ITs GERMINATION. ‘ é ‘ ; . 5-13 CHAPTER II Storace oF Foop in THE SEED : 7 ‘ : r . 14-24 CHAPTER II Movements, DevELopmMENT, AND MorPHotocy of THE SEEDLING 25-35 e CHAPTER IV Roots - : . ‘ A 3 3 ‘ ‘ . . 86-61 CHAPTER V Stems : ‘ : : . : r “ : 3 - 62-82 CHAPTER VI StrucTuRE OF THE STEM . : ‘ 7 i ‘ . 88-103 CHAPTER VII Living Parts oF tHE Stem; Work or THE STEM. ‘ . 104-118 CHAPTER VIII Bups . Z . ‘ . ‘ 7 : ‘ i ‘ . 119-129 vii viii CONTENTS CHAPTER IX nie LEAVES ‘ : : ‘ ! : ‘ : ‘ . 130-139 CHAPTER X LeaF-ARRANGEMENT FOR Exposure To Sun anp AIR; Move- MENTS OF LEAVES AND SHoots . ¢ ‘ : . 140-149 CHAPTER XI Mivute Structure oF LEAvEs; Functions or LEAVES. . 160-177 CHAPTER XII PROTOPLASM AND ITS PROPERTIES. “ ‘ . 178-185 CHAPTER XIII INFLORESCENCE, OR ARRANGEMENT OF FLowers on THR Stem 186-191 CHAPTER XIV Tue Srupy or TypicaL FLowers . i i . : . 192-196 CHAPTER XV PLAN AND STRUCTURE OF THE FLOWER AND ITS ORGANS . 197-207 CHAPTER XVI True Nature or Frorat Organs; Deraits or THER StRuc- TURE; FERTILIZATION . 2 : : . 5 . 208-216 CHAPTER XVII Tue Stupy or Tyrpicat Fruits ‘ - ‘ ‘ ‘ . 217-220 CHAPTER XVIII Tue Fruit ‘ , : 5 : ‘ , 5 4 . 221-227 CHAPTER XIX Tue CLASSIFICATION OF PLANTS j F i é 228-284 CONTENTS 1x CHAPTER XX PAGES TYPES oF CrYPToGaMS; THALLOPHYTES . f i . 285-276 CHAPTER XXI Types oF Cryprocams; BryrorpHyTes é » 277-285 CHAPTER XXII Types or CRYPTOGAMS; PYERIDOPHYTES . : . : . 286-297 3 CHAPTER XXIII Tue Evoxutionary History or PLAnts ‘ : - 298-305 Part II ECOLOGY, OR RELATIONS OF PLANTS TO THE WORLD ABOUT THEM CHAPTER XXIV Pianr Societies " : ‘ ‘ 5 i ‘ . 807-3823 CHAPTER XXV BoranicaAL GEOGRAPHY : 3 F . . 324-335 CHAPTER XXVI Parasires, Exstavep Piants, Messmates, Carnivorous Piants 336-344 CHAPTER XXVII {_ How Prants PRoTecT THEMSELVES FROM ANIMALS . . 845-362 x CONTENTS CHAPTER XXVIII PAGES EcoLocy or FLrowers 5 5 ‘ 3 : : ‘ . 8538-372 CHAPTER XXIX How Prants are ScaTTERED AND PROPAGATHD. i : . 373-386 CHAPTER XXX Tue SrruecLte ror EXISTENCE AND THE SURVIVAL OF THE FIrrest 5 7 ‘ é ‘ , 3 F 7 . 387-395 LIST OF PLATES Frontispiece. Jack-in-the-pulpit, a typical shade-plant, with large, thin leaves. Facing page Prats I, Sand-dunes with sea rye grass. Deep-rooted, with exten- sively running rootstocks . : : s ‘ , . . 76 Prate II. Pollarded willows, showing growth of slender twigs from adventitious buds é . ‘i : ‘ . j ‘ . 128 Puate IT. Japanese ivy, a tendril-climber growing on face of a building, showing leaves all exposed to sunlight at the most advantageous angle . , é $ ot : , . 140 Prate IV. Cypress swamp, showing ‘‘ Spanish moss’’ (Tillandsia), a phanerogamic epiphyte practically leafless, the work ordinarily done by leaves devolving on the slender stems. The cypress trees are furnished with ‘‘ knees’’ or projections from the roots, which are thought by some to absorb air . 3 . . . 158 Puate V. Indian pipe, a saprophytic seed-plant, wholly destitute of chlorophyll and with scales instead of foliage leaves - . 168 Prare VI. Fan palms, showing general habit of the tree, and large projecting bases of old petioles left after the decay of the leaves 176 Puate VII. A tree yucca in the Mohave Desert, a characteristic xerophytic tree. Other sparse desert vegetation is also shown . 316 Pirate VIII. Belt of trees along a Nebraskan river, showing depend- ence offoreston watersupply . . . . . . «. 884 Pirate IX. Cottonwood. Tree largely overgrown with American mistletoe, near Mesilla, New Mexico. The photograph was taken in winter, when the tree was leafless, so that all the foliage shown is that of the mistletoe é , 2 . : . , . 886 Pirate X. Humming-bird visiting flowers of the trumpet creeper. This is one of the best North American examples of a flower mainly pollinated by birds . i % é 5 , 3 . 862 Puare XI. Asters and golden-rods, Composite, illustrating the principle of grouping many small flowers into heads (and in the golden-rod the heads into rather close clusters) to facilitate the visits of insects . ; : : : : F . . 872 FOUNDATIONS OF BOTANY INTRODUCTION “Botany is the science which endeavors to answer every reason- able question about plants.” ! THE plant is a living being, provided generally with many parts, called organs, which it uses for taking in nour- ishment, for breathing, for protection against its enemies, and for reproducing itself and so keeping up the numbers of its own kind. The stugy of the individual plant there- fore embraces a variety of topics, and the examination of its relation to others introduces many more subjects. Morphology, or the science of form, structure, and so on, deals with the plant without much regard to its character as a living thing. Under this head are studied the forms of plants and the various shapes or disguises which the same sort of organ may take in different kinds of plants, their gross structure, their microscopical structure, their classification, and the successive stages in the develop- ment of the individual plant. Plant Physiology treats of the plant in action, how it lives, breathes, feeds, grows, and produces others like itself. Geographical Distribution, or botanical geography, dis- cusses the range of the various kinds of plants over the 1 Professor George L. Goodale. 1 2 FOUNDATIONS OF BOTANY earth’s surface. Another subdivision of botany, usually studied along with geology, describes the history of plant life on the earth from the appearance of the first plants until the present time. Systematic Botany, or the classification of plants, should naturally follow the examination of the groups of seed- plants and spore-plants. Plant Ecology treats of the relations of the plant to the conditions under which it lives. Under this division of the science are studied the effects of soil, climate, and friendly or hostile animals and plants on the external form, the internal structure, and the habits of plants. This is in many respects the most interesting department of botany, but it has to be studied for the most part out of doors. Many of the topics suggested in the above outline cannot well be studied in the high school. There is not usually time to take up more than the merest outline of botanical geography, or to do much more than mention the impor- tant subject of Economic Botany —the study of the uses of plants to man. It ought, however, to be possible for the student to learn in his high-school course a good deal about the simpler facts of morphology and of vegetable physiology. One does not become a botanist — not even much of an amateur in the subject —by reading books about botany. It is necessary to study plants themselves, to take them to pieces and make out the connection of their parts, to examine with the microscope small portions of the exterior surface and thin slices of all the variously built materials or tissues of which the plant consists. All this ~ can be done with living specimens or with those taken INTRODUCTION 3 from dead parts of plants that have been preserved in any suitable way, as by drying or by placing in alcohol or other fluids which prevent decay. Living plants must be studied in order to ascertain what kinds of food they take, what kinds of waste substances they excrete, how afd where their growth takes place and what circumstances favor it, how they move, and indeed to get as complete an idea as possible of what has been called the behavior of plants. Since the most familiar and most interesting plants spring from seeds, the beginner in botany can hardly do better than to examine at the outset the structure of a few familiar seéds, then sprout them and watch the growth of the seedlings which spring from them. Afterwards he may study in a few typical examples the organs, structure, and functions of seed-plants, trace their life history, and so, step by step, follow the process by which a new crop of seeds at last results from the growth and development of such a seed as that with which he began. After he has come to know in a general way about the structure and functions of seed-plants, the student may become acquainted with some typical cryptogams or spore- plants. There are so many groups of these that only a few representative ones can be chosen for study. Part I STRUCTURE, FUNCTIONS, AND CLASSIFI- CATION OF PLANTS CHAPTER I THE SEED AND ITS GERMINATION 1. Germination of the Squash Seed. — Soak some squash seeds in tepid water for twelve hours or more. Plant these about an inch deep in damp sand or pine sawdust or peat-moss in a wooden box which has had holes enough bored through the bottom so that it will not hold water. Put the box in a warm place (not at any time over 70° or 80° Fahrenheit),! and cover it loosely with a board or a pane of glass. Keep the sand or sawdust moist, but not wet, and the seeds will germinate. As soon as any of the seeds, on being dug up, are found to have burst open, sketch one in this condition,’ noting the manner in which the outer seed-coat is split, and continue to examine the seedlings at intervals of two days, until at least eight stages in the growth of the plantlet have been noted.® 1 Here and elsewhere throughout the book temperatures are expressed in Fahrenheit degrees, since with us, unfortunately, the Centigrade scale is not the familiar one, outside of physical and chemical laboratories. 2 The student need not feel that he is expected to make finished drawings to record what he sees, but some kind of careful sketch, if only the merest outline, is indispensable. Practice and study of the illustrations hereafter given will soon impart some facility even to those who have had little or no instruction in drawing. Consult here Figs. 9 and 89. 8 The class is not to wait for the completion of this work (which may, if desirable, be done by each pupil at home), but is to proceed at once with the examination of the squash seed and of other seeds, as directed in the follow- ing sections, and to set some beans, peas, and corn to sprouting, so that they may be studied at the same time with the germinating squashes. 5 6 FOUNDATIONS OF BOTANY Observe particularly how the sand is pushed aside by the rise of the young seedlings. Suggest some reason for the manner in which f the sand is penetrated by the rising stem. 2. Examination of the Squash Seed. — Make a sketch of the dry seed, natural size. Note the little scar at the pointed end of the seed where the latter was attached to its place of growth in the squash. Label this hilum. Note the little hole in the hilum; it is the micropyle, seen most plainly in a soaked seed. (If there are two depressions on the hilum the deeper one is the micropyle.) Describe the color and texture’of the outer coating of the seed. With a scalpel or a very ----e sharp knife cut across near the middle a seed that has been soaked in water for twenty- = four hours. Squeeze one of the portions, ” held edgewise between the thumb and finger, in such a way as to separate slightly the halves into which the contents of the seed is --p naturally divided. Examine with the mag- nifying glass the section thus treated, make a sketch of it, and label the shell or covering of the seed and the kernel within this. Taking another soaked seed, chip away i the white outer shell, called: the testa, and Rey ---C observe the thin, greenish inner skin (Fig. 1, e), with which the kernel of the seed is closely covered.1 Strip this off and sketch the uncovered ker- G gy LUT CN Cee TOT omaha et AIAN aegis ane oe nel or embryo. Note that at one end it tapers of a Squash Seed. (Magni- to a point. This pointed portion, known fied about tive times.) as the hypocotyl, will develop after the seed sprouts into the stem of the plantlet, like that shown at c in Fig. 2. Split the halves of the kernel entirely apart from each other, 1 See footnote 2 to Sect. 18, THE SEED AND ITS GERMINATION 7 noticing that they are only attached for a very little way next to the hypocotyl, and observe the thickness of the halves and the slight unevenness of the inner’surfaces. or cotyledons. These halves are called seed-leaves Have ready some seeds which have been soaked for twenty-four hours and then left in a loosely covered jar on damp blotting paper at a temperature of 70° or over until they have begun to sprout. Split one of these seeds apart, separating the cotyledons, and observe, at the junction of these, two very slender pointed objects, the rudimentary leaves of the plumule or first bud (Fig. 1, p). 3. Examination of the Bean. —Study the seed, both dry and after twelve hours’ soaking, in the same general way in which the squash seed has just been examined.} Notice the presence of a dis- tinct plumule, consisting of a pair of rudimentary leaves between the cotyledons, just where they are joined to the top of the hypo- cotyl. In many seeds (as the pea) the plumule does not show dis- tinct leaves. But in all cases the plumule contains the growing point, the tip of the stem from which all the upward growth of the plant is to proceed. Fic. 2.— The Castor Bean and its Germination. A, longitudinal section of ripe seed; 1, testa; co, cotyledon; v, hypocotyl; B, sprouting seed covered with endo- sperm; C, same, with half of endo- sperm removed; D, seedling; r, pri- mary root; r’, secondary roots; c, arch of hypocotyl. Make a sketch of these leaves as they lie in place on one of the cotyledons, after the bean has been split open. 1 The larger the variety of bean chosen, the easier it will be to see and sketch the several parts. The large red kidney bean, the horticultural bean, or the lima bean will do well for this examination... 8 FOUNDATIONS OF BOTANY Note the cavity in each cotyledon caused by the pressure of the plumule and of the hypocotyl. 4, Examination of the Pea. —There are no very important points, of difference between the bean and pea, so far as the structure of the seed is concerned, but the student should rapidly dissect a few soaked peas to get an idea of the appearance of the parts, since he is to study the germination of peas in some detail. ‘, Make only one sketch, that of the hypocotyl as seen in position after the removal of the seed-coats.! 5. Germination of the Bean or the White Lupine, the Pea, and the Grain of Corn. — Soak some beans or lupine seeds as directed in Section 8, plant them,? and make a series of sketches on the same general plan as those in Fig. 9. Follow the same directions with some peas and some corn. In the case of the corn, make six or more sketches at various stages to illus- trate the growth of the plumule and the formation of roots; first a main root from the base of the hypocotyl, then others more slender from the same region, and later on still others from points higher up on the stem (see Fig. 15). The student may be able to dis- cover what becomes of the large outer part of the embryo. This is really the single cotyledon of the corn (Fig. 6). It does not as a whole rise above ground, but most of it remains in the buried grain, and acts as a digesting and absorbing organ through which the endosperm or food stored outside of the embryo is transferred into the growing plant, as fast as it can be made liquid for that purpose. 6. Germination of the Horse-Chestnut.— Plant some seeds of the horse-chestnut or the buckeye, study their mode of germination, and observe the nature and peculiar modifications of the parts. Consult Gray’s Structural Botany, Vol. I, pp. 19, 20. 7. Conditions Requisite for Germination. —- When we try to enumerate the external conditions which can affect 1 The teacher will find excellent sketches of most of the germinating seeds described in the présent chapter in Miss Newell’s Outlines of Lessons in Botany, Part I. 2The pupil may economize space by planting the new seeds in boxes from which part of the earlier planted seeds have been dug up for use in sketching, ete. THE SEED AND ITS GERMINATION 9 germination, we find that the principal ones are heat, moisture, and presence of air. A few simple experiments will show what influence these conditions exert. 8. Temperature. Common observation shows that a moderate amount of warmth is necessary for the sprout- ing of seeds. Every farmer or gardener knows that during a cold spring many seeds, if planted, will rot in the ground. But a somewhat exact experiment is neces- sary to show what is the best temperature for seeds to grow in, and whether variations in the temperature make more difference in the quickness with which they begin to germinate or in the total per cent which finally succeed. EXPERIMENT I Relation of Temperature to Germination. — Prepare at least four teacups or tumblers, each with wet soft paper packed in the bottom to a depth of nearly an inch. Have a tightly fitting cover over each. Put in each vessel the same number of soaked peas. Stand the ves- sels with their contents in places where they will be exposed to dit- ferent, but fairly constant, temperatures, and observe the several temperatures carefully with a thermometer. Take pains to keep the tumblers in the warm places from drying out, so that their contents will not be less moist than that of the others. The following series is merely suggested, — other values may be found more convenient. Note the rate of germination in each place and record in tabular form as follows: No. of seeds sprouted in 24 hrs. 48 hrs. 72 hrs. 96 hrs. ete. At 32°, — At 50°, SSS ee At 70°, —S>= o> ——- Ss Ss —-_— At 90°,} — $—- Ss Ss —--— — 1 For the exact regulation of the temperatures a thermostat (see Handbook) is desirable. If one is available, 4 maximum temperature of 100° or over should be tried. 10 FOUNDATIONS OF BOTANY 9. Moisture. — What was said in the preceding section in regard to temperature applies also to the question of the best conditions for germination as regards the supply of moisture. The soil in which seeds grow out of doors is always moist; it rests with the experimenter to find out approximately what is the best amount of moisture. EXPERIMENT II? Relation of Water to Germination. Arrange seeds in several vessels as follows: In the first put blotting paper that is barely moistened; on this put some dry seeds. In the second put blotting paper that has been barely moistened ; on this put seeds that have been soaked for twenty-four hours. In the third put water enough to soak the paper thor- oughly; use soaked seeds. In the fourth put water enough to half cover the seeds. Place the vessels where they will have same temperature and note the time of ger- mination. Tabulate your re- sults as in the previ- ous experiment. Fia. 3,—Soaked Peas in Stoppered Bottle, ready for Exhaustion of Air, 10. Relation of the Air-Supply to Germination. — If we wish to see how soaked seeds will behave with hardly any air supply, it is necessary to place them in a bottle arranged 1 This may be made a home experiment. THE SEED AND ITS GERMINATION 11 as shown in Fig. 3, exhaust the air by connecting the glass tube with an air-pump, which is then pumped vigorously, and seal the tube while the exhaustion is going on. The sealing is best done by holding a Bunsen flame under the middle of the horizontal part of the tube. A much easier experiment, which is nearly as satisfactory, can, however, be performed without the air-pump. EXPERIMENT III Will Seeds Germinate well without a Good Supply of Air? — Place some soaked seeds on damp blotting paper in the bottom of a bottle, using seeds enough to fill it three-quarters full, and close tightly with a rubber stopper. Place a few other seeds of the same kind in a second bottle; cover loosely. Place the bottles side by side, so that they will have the same conditions of light and heat. Watch for results, and tabulate as in previous experiments. Most seeds will not germinate under water, but those of the sunflower will do so, and therefore Exp. III may be varied in the following manner: Remove the shells carefully from a considerable number of sun- flower seeds. Try to germinate one lot of these in water which has been boiled in a flask to remove the air, and then cooled in the same flask. Over the water, with the seeds in it, a layer of cotton- seed oil about a half inch deep is poured, to keep the water from contact with air. In this bottle then there will be only seeds and air-free water. Try to germinate another lot of seeds in a bottle half filled with ordinary water, also covered with cotton-seed oil. Results? 11. Germination involves Chemical Changes.— If a ther- mometer is inserted into a jar of sprouting seeds, for 1 These are really fruits, but the distinction is not an important one at this time. 12 FOUNDATIONS OF BOTANY instance peas, in a room at the ordinary temperature, the peas will be found to be warmer than the surrounding air. This rise of temperature is at least partly due to the absorption from the air of that substance in it which supports the life of animals and maintains the burning of fires, namely, oxygen. The union of oxygen with substances with which it can combine, that is with those which will burn, is called oxidation. This kind of chemical change is universal in plants and animals while they are in an active condition, and the energy which they manifest in their growth and movements is as directly the result of the oxidation going on inside them as the energy of a steam engine is the result of the burning of coal or other fuel under its boiler. In the sprouting seed much of the energy produced by the action of oxygen upon oxidizable portions of its con- tents is expended in producing growth, but some of this energy is wasted by being transformed into heat which escapes into the surrounding soil. It is this escaping heat which is detected by a thermometer thrust into a quantity of germinating seeds. EXPERIMENT IV Effect of Germinating Seeds upon the Surrounding Air. — When Exp. III has been finished, remove a little of the air from above the peas in the first bottle. This can easily be done with a rubber bulb attached to a short glass tube. Then bubble this air through some clear, filtered limewater. Also blow the breath through some lime- water by aid of a short glass tube. Explain any similarity in results obtained. (Carbon dioxide turns limewater milky.) After- wards insert into the air above the peas in the same bottle a lighted pine splinter, and note the effect upon its flame, THE SEED AND ITS GERMINATION 13 12. Other Proofs of Chemical Action.— Besides the proof of chemical changes in germinating seeds just described, there are other kinds of evidence to the same effect. Malt, which is merely sprouted barley with its germi- nation permanently stopped at the desired point by the application of heat, tastes differently from the unsprouted grain, and can be shown by chemical tests to have suffered a variety of changes. If you can get unsprouted barley and malt, taste both and see if you can decide what sub- stance is more abundant in the malt. Germinating kernels of corn undergo great alterations in their structure; the starch grains are gradually eaten away until they are ragged and full of holes and finally disappear. 13. The Embryo and its Development. —‘The miniature plant, as it exists ready formed and alive but inactive in the seed, is called the embryo. In the seeds so far ex- amined, practically the entire contents of the seed-coats consist of the embryo, but this is not the case with the great majority of seeds, as will be shown in the following chapter. CHAPTER II STORAGE OF FOOD IN THE SEED 14. Food in the Embryo. — Squash seeds are not much used for human food, though both these and melon seeds are occasionally eaten in parts of Europe; but beans and peas are important articles of food. Whether the material accumulated in the cotyledons is an aid to the growth of the young plant may be léarned from a simple experiment. 15. Mutilated and Perfect Seedlings. — One of the best ways in which to find out the importance and the special use of any part of a plant is to re- move the part in question and see how the plant be- haves afterward. EXPERIMENT V! Are the Cotyledons of a Pea of any Use to the Seedling ? — Sprout several peas on blotting paper. When the plumules appear, carefully cut away the cotyledons from some of the seeds. Place on a perforated cork, as shown in Fig. 4, one or two seedlings from Fic. 4.—Germinating Peas, growing in Water, one deprived of its Cotyledons. 1 May be a home experiment. 14 STORAGE OF FOOD IN THE CELLS 15 which the cotyledons have been cut, and as many which have not been mutilated, and allow the roots to extend into the water. Let them grow for some days, or even weeks, and note results. 16. Food stored in Seeds in Relation to Growth after Germination. — If two kinds of seeds of somewhat similar character, one kind large and the other small, are allowed to germinate and grow side by side, some important infer- ences may be drawn from their relative rate of growth. EXPERIMENT VI} Does the Amount of Material in the Seed have anything to do with the Rate of Growth of the Seedling ?—-Germinate ten or more clover seeds, and about the same number of peas, on moist blotting paper under a bell-jar. After they are well sprouted, transfer both kinds of seeds to fine cotton netting, stretched across wide-mouthed jars nearly full of water. The roots should dip into the water, but the seeds must not do so. Allow the plants to grow until the peas are from four to six’inches high. Some of the growth in each case depends on material gathered from the air and water, but most of it, during the very early life of the plant, is due to the reserve material stored in the seed. Where is it in the seeds so far studied? Proof? 17. Storage of Food outside of the Embryo. — In very many cases the cotyledons contain little food, I I but there is a supply of it stored Fic.5.—Seeds with Endosperm, in the seed beside or around them oe I, asparagus (magnified). (Figs. 2, 5, and 6). II, poppy (magnified). 18, Examination of the Four-o’clock Seed. Examine the exter- nal surface of a seed? of the four-o’clock, and try the hardness of 1 May be a home experiment. 2Strictly speaking, a fruit. 16 FOUNDATIONS OF BOTANY the outer coat by cutting it with a knife. From seeds which have been soaked in water at least twenty-four hours peel off the coatings and sketch the kernel. Make a cross-section of one of the soaked seeds which has not been stripped of its coatings, and sketch the sec- tion as seen with the magnifying glass, to show the parts, especially the two cotyledons, lying in close contact and encircling the white, starchy-looking endosperm.} The name endosperm is applied to food stored in parts of the seed other than the embryo.?) With a mounted needle pick out the little almost spherical mass of endosperm from inside the cotyledons of a seed which has been deprived of its coats, and sketch the embryo, noting how it is curved so as to enclose the endosperm almost completely. 19. Examination of the Kernel of In- dian Corn. — Soak some grains of large yellow field corn * for about three days. Sketch an unsoaked kernel, so as to show the grooved side, where the germ lies. Observe how this groove has be- come partially filled up in the soaked ’ Fig. 6.—Lengthwise Section of kernels. Oe eee Sea a Remove the thin, tough skin from y, yellow, oily part of endosperm, ©N¢ of the latter, and notice its transpar- w, white, starchy part of en- ency. This skin —the bran of unsifted wees ae i. &® corn meal — does not exactly correspond with the endosperm for absorp- to the testa and inner coat of ordinary tion of food from it; r, the seeds, since the kernel of corn, like all Dear ane other grains (and like the seed of the four-o’clock), represents not merely the seed, but also the seed-vessel in which it was formed and grew, and is therefore. a fruit. 1 Buckwheat furnishes another excellent study in seeds with endosperm. Like that of the four-o’clock, it is, strictly speaking, a fruit; so also is a grain of corn. 2 In the squash seed the green layer which covered the embryo represents the remains of the endosperm. 3 The varieties with long, flat kernels, raised in the Middle and Southern States under the name of ‘“‘dent corn,” are the best. STORAGE OF FOOD IN THE SEED 17 Cut sections of the soaked kernels, some transverse, some length- wise and parallel to the flat surfaces, some lengthwise and at right angles to the flat surfaces. Try the effect of staining some of these sections with iodine solution. : Make a sketch of one section of each of the three kinds, and label the dirty white portion, of cheesy consistency, embryo; and the yel- low portions, and those which are white and floury, endosperm. Chip off the endosperm from one kernel so as to remove the embryo free from other parts.!_ Notice its form, somewhat triangular in outline, sometimes nearly the shape of a beechnut, in other speci- mens nearly like an almond. Estimate what proportion of the entire bulk of the soaked kernel is embryo. ; Split the embryo lengthwise so as to show the slender, somewhat conical plumule.? 20. Corn Seedlings deprived of Endosperm.— An experi- ment parallel to No. V serves to show the function and the importance of the endosperm of Indian corn. EXPERIMENT VII Of how much Use to the Corn Seedling is the Endosperm ? — Sprout kernels of corn on blotting paper. When they get fairly started, cut away the endosperm carefully from several of the seeds. Sus- pend on mosquito netting on the surface of water in the same jar two or three seedlings which have had their endosperm removed, and as many which have not been mutilated. Let them grow for some weeks, and note results. 21. Starch. Most common seeds contain starch. Every one knows something about the appearance of ordi- 1The embryo may be removed with great ease from kernels of rather ma- ture green corn. Boil the corn for about twenty minutes on the cob, then pick the kernels off one by one with the point of a knife. They may be preserved indefinitely in alcohol of 50 or 75%. 2 The teacher may well consult Figs. 56-61, inclusive, in Gray’s Structural Botany. 18 FOUNDATIONS OF BOTANY nary commercial starch as used in the laundry, and as sold for food in packages of cornstarch. When pure it is characterized not only by its lustre, but also by its peculiar velvety feeling when rubbed between the fingers. 22. The Starch Test. — It is not always easy to recog- nize at sight the presence of starch as it. occurs in seeds, but it may be detected by a very simple chemical test, namely, the addition of a solution of iodine.? 3 EXPERIMENT VIII? Examination of Familiar Seeds with Iodine. Cut in two with a sharp knife the seeds to be experimented on, then pour on each, drop by drop, some of the iodine solution. Only a little is necessary; sometimes the first drop is enough. If starch is present, a blue color (sometimes almost black) will appear. If no color is obtained in this way, boil the pulverized seeds for a moment in a few drops of water, and try again. Test in this manner corn, wheat (in the shape of flour), oats (in oatmeal), barley, rice, buckwheat, flax, rye, sunflower, four-o’clock, morning-glory, mustard seed, beans, peanuts, Brazil-nuts, hazelnuts, and any other seeds that you can get. Report your results in tabu- lar form as follows: Mucx Starch LittLe STaRcH No Srarce Color: blackish or Color: pale blue or Color: brown, orange, dark blue. greenish. or yellowish. 23. Microscopical Examination of Starch.?— Examine starch in water with a rather high power of the microscope (not less than 200 diameters). 1The tincture of iodine sold at the drug-stores will do, but the solution prepared as directed in the Handbook answers better. This may be made up in quantity, and issued to the pupils in drachm vials, to be taken home and used there, if the experimenting must be done outside of the laboratory or the schoolroom. 2May be a home experiment. 8 At this point the teacher should give a brief illustrated talk on the con- struction and theory of the compound microscope. STORAGE OF FOOD IN THE SEED 19 Pulp scraped from a potato, that from a canna rootstock, wheat flour, the finely powdered starch sold under the commercial name of “cornstarch” for cooking, oat- TN meal, and buckwheat finely pow- dered in a mortar, will furnish excellent examples of the shape and markings of starch grains. Sketch all of the kinds exam- ined, taking pains to bring out the markings.1 Compare the sketches with Figs. 7 and 8. With a medicine-dropper or a very small pipette run in a drop of iodine solution under one edge of the cover-glass, at the same time withdrawing a little water from . the margin opposite by touching to it a bit of blotting paper. | Fig. 7.— Canna Starch. (Magnified 300 diameters.) C- ~~ amt ain APR SSIS ps OE ge I ?--- “SQO0Q0OGDO0O m.--- KX PEI ORES “x CTI CIO ODBC Se Oe — — : Fia. 8.—Section through Exterior Part of a Grain of Wheat. e, cuticle or outer layer of bran; ep, epidermis; m, layer beneath epidermis ; qu, sch, layers of hull next to seed-coats; br, n, seed-coats; Ki, layer containing proteid grains ; st, cells of the endosperm filled with starch. (Greatly magnified.) 1 The markings will be seen more distinctly if care is taken not to admit too much light to the object. Rotate the diaphragm beneath the stage of the microscope, or otherwise regulate the supply of light, until the opening is found which gives the best effect. 20 FOUNDATIONS OF BOTANY Examine again and note the blue coloration of the starch grains and the unstained or yellow appearance of other substances in the field. Cut very thin slices from beans, peas, or kernels of corn; mount in water, stain as above directed, and draw as seen under the microscope. Compare with Figs. 7 and 8.!_ Note the fact that the starch is not packed away in the seeds in bulk, but that it is enclosed in little chambers or cells. 24. Plant-Cells. — Almost all the parts of the higher plants are built up of little separate portions called cells. The cell is the unit of plant-structure, and bears some- thing the same relation to the plant of which it is a part that one cell of a honeycomb does to the whole comb. But this comparison is not a perfect one, for neither the waxen wall of the honeycomb-cell nor the honey within it is alive, while every plant-cell is or has been alive. And even the largest ordinary honeycomb consists of only a few hundred cells, while a large tree is made up of very many miillons of cells. The student must not conceive of the cell as merely a little chamber or enclosure. The living, more or less liquid, or mucilage-like, or jelly-like substance known as protoplasm, which forms a large portion of the bulk of living and growing cells, is the all-important part of such a cell. Professor Huxley has well called this substance “the physical basis of life.” Cells are of all shapes and sizes, from little spheres a ten-thousandth of an inch or less in diameter to slender tubes, such as fibers of cotton, several inches long. To get an idea of the appearance of some rather large cells, scrape a little pulp from a ripe, mealy apple, and examine it first with 1The differentiation between the starch grains, the other cell-contents, and the cell-walls will appear better in the drawings if the starch grains are sketched with blue ink. STORAGE OF FOOD IN THE SEED 21 a strong magnifying glass, then with a moderate power of the compound microscope. To see how dead, dry cell- walls, with nothing inside them, look, examine (as before) a very thin slice of elder pith, sunflower pith, or pith from a dead cornstalk. Look also at the figures inChapter VI of this book. Notice that the simplest plants (Chapter XX) consist of a single cell each. The study of the structure of plants is the study of the forms which cells and groups of cells assume, and the study of plant physiology is the study of what cells and cell combinations do. 25. Absorption of Starch from the Cotyledons. — Examine with the microscope, using a medium power, soaked beans and the cotyle- dons from seedlings that have been growing for three or four weeks. Stain the sections with iodine solution, and notice how completely the clusters of starch grains that filled most of the cells of the un- sprouted cotyledons have disappeared from the shriveled cotyledons of the seedlings. A few grains may be left, but they have lost their sharpness of outline. 26. Oil.— The presence of oil in any considerable quantity in seeds is not as general as is the presence of starch, though in many common seeds there is a good deal of it. Sometimes the oil is sufficiently abundant to make it worth while to extract it by pressure, as is done with flax- seed, cotton-seed, the seeds of some plants of the cress family, the “castor bean,” and other seeds. 27. Dissolving Oil from Ground Seeds. — It is not possi- ble easily to show a class how oil is extracted from seeds by pressure; but there are several liquids which readily dissolve oils and yet have no effect on starch and most of the other constituents of seeds. 22 FOUNDATIONS OF BOTANY EXPERIMENT IX Extraction of Oil by Ether or Benzine.—To a few ounces of ground flaxseed add an equal volume of ether or benzine. Let it stand ten or fifteen minutes and then filter. Let the liquid stand in a saucer or evaporating dish in a good draught till it has lost the odor of the ether or benzine. Describe the oil which you have obtained. Of what use would it have been to the plant? Tf the student wishes to do this experiment at home for himself, he should bear in mind the following : Caution. — Never handle benzine or ether near a flame or stove. A much simpler experiment to find oil in seeds may readily be performed by the pupilat home. Put the material to be studied, e.g., flaxseed meal, corn meal, wheat flour, cotton-seed meal, buckwheat flour, oatmeal, and so on, upon little labeled pieces of white paper, one kind of flour or meal on each bit of paper. Place all the papers, with their contents, on a perfectly clean plate, free from cracks, or on a clean sheet of iron, and put this in an oven hot enough nearly (but not quite) to scorch the paper. “After half an hour remove the plate from the oven, shake off the flour or meal from each paper, and note the results, a more or less distinct grease spot showing the presence of oil, or the absence of any stain that there was little or no oil in the seed examined. 28. Albuminous Substances. — Albuminous substances or proteids occur in all seeds, though often only in small quantities. They have nearly the same chemical compo- sition as white of egg and the curd of milk among animal substances, and are essential to the plant, since the living and growing parts of all plants contain large quantities of proteid material. Sometimes the albuminous constituents of the seed occur in more or less regular grains (Fig. 8, at K7). But much of the proteid material of seeds is not in any STORAGE OF FOOD IN THE SEED 23 form in which it can be recognized under the microscope. One test for its presence is the peculiar smell which it produces in burning. Hair, wool, feathers, leather, and lean meat all produce a well-known sickening smell when scorched or burned, and the similarity of the proteid mate- rial in such seeds as the bean and pea to these substances is shown by the fact that scorching beans and similar seeds give off the familiar smell of burnt feathers. 29. Chemical Tests for Proteids.— All proteids (and very few other substances) are turned yellow by nitric acid, and this yellow color becomes deeper or even orange when the yellowish substance is moistened with ammonia. They are also turned yellow by iodine solution. Most proteids are turned more or less red by the solution of nitrate of mercury known as Millon’s reagent.? EXPERIMENT X Detection of Proteids in Seeds. — Extract the germs from some soaked kernels of corn and bruise them; soak some wheat-germ meal for a few hours in warm water, or wash the starch out of wheat- flour dough; reserving the latter for use, place it in a white saucer or porcelain evaporating dish, and moisten well with Millon’s reagent or with nitric acid; examine after fifteen minutes. 30. The Brazil-Nut as a Typical Oily Seed. — Not many familiar seeds are as oily as the Brazil-nut. Its large size makes it convenient for examination, and the fact that this nut is good for human food makes it the more interesting to investigate the kinds of plant-food which it contains. 1 See Handbook. 24 FOUNDATIONS OF BOTANY EXPERIMENT XI Testing Brazil-Nuts for Plant-Foods.— Crack fifteen or twenty Brazil-nuts, peel off the brown coating from the kernel of each, and then grind the kernels to a pulp in a mortar. Shake up this pulp with ether, pour upon a paper filter, and wash with ether until the washings when evaporated are nearly free from oil. The funnel containing the filter should be kept covered as much as possible until the washing is finished. Evaporate the filtrate to procure the oil, which may afterwards be kept in a glass-stoppered bottle. Dry the powder which remains on the filter and keep it in a wide- mouthed bottle. Test portions of this powder for proteids and for starch. Explain the.results obtained. 31. Other Constituents of Seeds. — Besides the substances above suggested, others occur in different seeds. Some of these are of use in feeding the seedling, others are of value in protecting the seed itself from being eaten by animals or in rendering it less liable to decay. In such seeds as that of the nutmeg, the essential oil which gives it its characteristic flavor probably makes it unpalatable to animals and at the same time preserves it from decay. Date seeds are so hard and tough that they cannot be eaten and do not readily decay. Lemon, orange, horse- chestnut and buckeye seeds are too bitter to be eaten, and the seeds of the apple, cherry, peach, and plum are some- what bitter. The seeds of larkspur, thorn-apple,! croton, the castor- oil plant, nux vomica, and many oEner kinds of plants contain active poisons. 1 Datura, commonly called “ Jimpson weed.” CHAPTER III MOVEMENTS, DEVELOPMENT, AND MORPHOLOGY OF THE SEEDLING 32. How the Seedling breaks Ground. — As the student has already learned by his own observations, the seedling does not always push its way straight out of the ground. Corn, like all the other grains and grasses, it is true, sends a tightly rolled, pointed leaf vertically upward into the air. But the other seedlings examined usually will not be found to do anything of the sort. The squash seedling is a good one in which to study what may be called the arched hypocotyl type of germination. If the ¢,5—% seed when planted is laid hori- s . - Cc es ( () A B Cc D E Fic. 9.— Successive Stages in the Life History of the Squash Seedling. GG, the surface of the ground; 1, primary root; 1’, secondary root; ¢, hypocoty1 ; a, arch of hypocotyl; co, cotyledons. zontally on one of its broad surfaces, it usually goes through some such changes of position as are shown in Fig. 9. 25 26 ' FOUNDATIONS OF BOTANY The seed is gradually tilted until, at the time of their emergence from the ground (at C), the cotyledons are almost vertical. The only part above the ground-line G, G, at this period, is the arched hypocotyl. Once out of ground, the cotyledons soon rise, until (at H) they are again ver- tical, but with the other end up from that which stood highest in C. Then the two cotyledons separate until they once more lie horizontal, pointing away from each other. Can you suggest any advantage which the plant derives from having the cotyledons dragged out of the ground rather than having them pushed out, tips first? 33. Cause of the Arch. — It is evident that a flexible object like the hypocotyl, when pushed upward through the earth, might easily be bent into an arch or loop. Whether the shape which the hypocotyl assumes is wholly caused by the resistance of the soil can best be ascertained by an experiment. - EXPERIMENT XII Is the Arch of the Hypocotyl due to the Pressure of the Soil on the Rising Cotyledons ? — Sprout some squash seeds on wet paper under a bell-glass, and when the root is an inch or more long, hang several of the seedlings, roots down, in little stirrups made of soft twine, attached by beeswax and rosin mixture to the inside of the upper part of a bell-glass. Put the bell-glass on a large plate or a sheet of glass on which lies wet paper to keep the air moist. Note whether «. the seedlings form hypocotyl arches at all and, if so, whether the arch is more or less perfect than that formed by seedlings growing in earth, sand, or sawdust. 34. What pushes the Cotyledons up?—A very little study of any set of squash seedlings, or even of Fig. 9, is MORPHOLOGY OF THE SEEDLING 27 sufficient to show that the portion of the plant where roots and hypocotyl are joined neither rises nor sinks, but that the plant grows both ways from this part (a little above 7’ in Fig. 9, A and B). It is evident that as soon as the hypocotyl begins to lengthen much it must do one of two things: either push the cotyledons out into the air or else force the root down into the ground as one might push a stake down. What changes does the plantlet undergo, in passing from the stage shown at A to that of B and of C, making it harder and harder for the root to be thrust downward? 35. Use of the Peg. — Squash seedlings usually (though not always) form a sort of knob on the hypocotyl. This is known as the peg. Study a good many seedlings and try to find out what the lengthening of the hypocotyl, between the peg and the bases of the cotyledons, does for the little plant. Set a lot of squash seeds, hilum down, in moist sand or sawdust and see whether the peg is more or less developed than in seeds sprouted lying on their sides, and whether the cotyledons ip the case of the vertically planted seeds usually come out of the ground in the same condi- tion as do those shown in Fig. 9. 36. Discrimination between Root and Hypocotyl. — It is not always easy to decide by their appearance and be- - havior what part of the seedling is root and what part is hypocotyl. In a seedling visibly beginning to germinate, the sprout, as it is commonly called, which projects from the seed might be either root or hypocotyl or might consist of both together, so far as its appearance is concerned. A microscopic study of the cross-section of a root, compared with one of the hypocotyl, would show decided differences 28 FOUNDATIONS OF BOTANY of structure between the two. Their mode of growth is also different, as the pupil may infer after he has tried Exp. XIV. 37. Discrimination by Staining. — For some reason, per- haps because the skin or epidermis of the young root is not so water-proof as that of the stem, the former stains more easily than the latter does. EXPERIMENT XIII The Permanganate Test. — Make a solution of potassium perman- ganate in water, by adding about four parts, by weight, of the crystal- lized permanganate to 100 parts of water. Drop into the solution seedlings, ¢.g., of all the kinds that have been so far studied, each in its earliest stage of germination (that is, when the root or hypocotyl has pushed out of the seed half an inch or less), and also at one or two subsequent stages. After the seedlings have been in the solu- tion from three to five minutes, or as soon as the roots are consider- ably stained, pour off (and save) the solution and rinse the plants with plenty of clear water. Sketch one specimen of each kind, col- oring the brown-stained part, which is root, in some way so as to distinguish it from the unstained hypocotyl. Note particularly how much difference there is in the amount of lengthening in the several kinds of hypocotyl examined. Decide whether the peg of the squash seedling is an outgrowth of hypocotyl or of root. 38. Disposition made of the Cotyledons. — As soon as the young plants of squash, bean, and pea have reached a height of three or four inches above the ground it is easy to recognize important differences in the way in which they set out in life. The cotyledons of the squash increase greatly in sur- face, acquire a green color and a generally leaf-like appear- ance, and, in fact, do the work of ordinary leaves, In MORPHOLOGY OF THE SEEDLING 29 such a case as this the appropriateness of the name seed- leaf is evident enough, — one recognizes at sight the fact that the cotyledons are actually the plant’s first leaves. In the bean the leaf-like nature of the cotyledons is not so clear. They rise out of the ground like the squash cotyledons, but then gradually shrivel away, though they may first turn green and somewhat leaf-like for a time. In the pea (as in the acorn, the horse-chestnut, and many other seeds) we have quite another plan, the under- ground type of germination. Here the thick cotyledons no longer rise above ground at all, because they are so gorged with food that they could never become leaves ; but the young stem pushes rapidly up from the surface of the soil. : The development of the plumule seems to depend some- what on that of the cotyledons. The squash seed has cotyledons which are not too thick to become useful leaves, and so the plant is in no special haste to get ready any other leaves. The plumule, therefore, cannot be found with the magnifying glass in the unsprouted seed, and is almost microscopic in size at the time when the hypocotyl begins to show outside of the seed-coats. In the bean and pea, on the other hand, since the cotyle- dons cannot serve as foliage leaves, the later leaves must be pushed forward rapidly. In the bean the first pair are already well formed in the seed. In the pea they cannot be clearly made out, since the young plant forms several scales on its stem before it produces any full-sized leaves, and the embryo contains only hypocotyl, cotyledons, and a sort of knobbed plumule, well developed in point of size, representing the lower scaly part of the stem, 30 FOUNDATIONS OF BOTANY 39. Root, Stem, and Leaf. — By the time the seedling is well out of the ground it, in most cases, possesses the three kinds of vegetative organs, or parts essential to growth, of ordinary flowering plants, ¢.e., the root, stem, and leaf, or, as they are sometimes classified, root and shoot. All of these organs may multiply and increase in size as the plant grows older, and their mature structure will be studied in later chapters, but some facts concerning them can best be learned by watching their growth from the outset. 40. Young Roots grown for Examination. — Roots grow- ing in sand or ordinary soil cling to its particles so tena- ciously that they cannot easily be studied, and those grown in water have not quite the same form as soil-roots. Roots grown in damp air are best adapted for careful study. 41. Elongation of the Root. — We know that the roots of seedlings grow pretty rapidly from the fact that each day finds them reaching visibly farther down into the water or other medium in which they are planted. A sprouted Windsor bean in a vertical thistle-tube will send its root downward fast enough so that ten minutes’ watch- ing through the microscope will suffice to show growth. To find out just where the growth goes on requires a special experiment. EXPERIMENT XIV In what Portions of the Root does its Increase in Length take Place ? — Sprout some peas on moist blotting paper in a loosely covered tum- bler. When the roots are one and a half inches or more long, mark them along the whole length with little dots made with a bristle dipped in water-proof India ink, or a fine inked thread stretched on a little bow of whalebone or brass wire. MORPHOLOGY OF THE SEEDLING 31 Transfer the plants.to moist blotting paper under a bell-glass or an inverted battery jar and examine the roots at the end of twenty- four hours to see along what portions their length has increased ; continue observations on them for several days. 42. Root-Hairs. — Barley, oats, wheat, red clover, or buckwheat seeds soaked and then sprouted on moist blotting paper afford convenient material for studying root-hairs. ‘The seeds may be kept covered with a watch- glass or a clock-glass while sprouting. After they have begun to germinate well, care must be taken not to have them kept in too moist an atmosphere, or very few root-hairs will be formed. Examine with the magni- fying glass those parts of the root which have these appendages. Try to find out whether all the portions of the root are equally covered with hairs and, if not, where they are most abundant. (See also Sect. 53.) The root-hairs in plants growing under ordinary condi- tions are surrounded by the moist soil and wrap them- selves around microscopical particles of earth (Fig. 11). Thus they are able rapidly to absorb through their thin walls the soil-water, with whatever mineral substances it has dissolved in it. 43. The Young Stem.— The hypocotyl, or portion of the stem which lies below the cotyledons, is the earliest formed portion of the stem. Sometimes this lengthens but little; often, however, as the student knows from his own observations, the hypocotyl lengthens enough to raise the cotyledons well above ground, as in Fig. 10. The later portions of the stem are considered to be divided into successive nodes, — places at which a leaf (or 82 FOUNDATIONS OF BOTANY a scale which represents a leaf) appears; and internodes, — portions between the leaves. — The student should watch the growth of a seedling bean or pea and ascertain by actual measurements whether the internodes lengthen after they have once been formed, and if so, for how long a time the increase continues. Fie. 10. Fie. il. Fie. 10.— A Turnip Seedling, with the Cotyledons developed into Temporary Leaves. h, root-hairs from the primary root; 6, bare portion of the root, on which no hairs have as yet been produced. Fia. 11, —Cross-Section of a Root, a good deal magnified, showing root-hairs attached to particles of soil, and sometimes enwrapping these particles. 44. The First Leaves. — The cotyledons are, as already explained, the first leaves which the seedling possesses, — even if a plumule is found well developed in the seed, it was formed after the cotyledons. In those plants which have so much food stored in the cotyledons as to render these unfit ever to become useful foliage leaves, there is little or nothing in the color, shape, or general appearance MORPHOLOGY OF THE SEEDLING 33 of the cotyledon to make one think it really a leaf, and it is only by.studying many cases that the botanist is enabled to class all cotyledons as leaves in their nature, even if they are quite unable to do the ordinary work of leaves. The study of the various forms which the parts or organs of a plant may assume is called morphology ; it traces the rela- tionship of parts which are really akin to each other, though dissimilar in appearance and often in function. In seeds which have endosperm, or food stored outside of the embryo, the cotyledons usually become green and leaf-like, as they do, for example, in the four-o’clock, the morning-glory, and the buckwheat; but in the seeds of the grains (which contain endosperm) a large portion of the single cotyledon remains throughout as a thickish mass buried in the seed. In a few cases, as in the pea, there are scales instead of true leaves formed on the first nodes above the cotyledons, and it is only at about the third node above that leaves of the ordinary co kind appear. In the bean and some other |”, ~ plants which in general bear one leaf at a node along the stem, there is a pair produced at the first node above the cotyledons, and the leaves of this pair differ in shape from those which arise from the succeeding por- tions of the stem. 45. Classification of Plants by the Number of their Cotyledons. —In the pine family the jig 19 ~ Ger. germinating seed often displays more than minating Pine. two cotyledons, as shown in Fig. 12; in the “°*vietons majority of common flowering plants the seed con- tains two cotyledons, while in the lilies, the rushes, the 84 FOUNDATIONS OF BOTANY sedges, the grasses, and some other plants, there is but one cotyledon. Upon these facts is based the division of most flowering plants into two great groups: the dicotyledonous plants, which have two seed-leaves, and the monocotyledon- ous plants, which have one seed-leaf. Other important differences nearly always accompany the difference in number of cotyledons, as will be seen later. 46. Tabular Review of Experiments. — Make out a table containing a very brief summary of the experiments thus far performed, as follows: NUMBER MATERIALS OPERA- OBJECT OF AND TIONS RESULTS | INFERENCES SOUGHT EXPERIMENT APPARATUS | PERFORMED 47. Review Sketches. — Make out a comparison of the early life histories of all the other seedlings studied, by arranging in parallel columns a series of drawings of each, MORPHOLOGY OF THE SEEDLING 35 like those of Fig. 9, but in vertical series, the youngest of each at the top, thus: Brean Pra Corn ° First STAGE SEconD STAGE Tuirp STAGE FourtH STAGE Firth STAGE ETC. CHAPTER IV ROOTS ! 48. Origin of Roots. — The primary root originates from the lower end of the hypocotyl, as the student learned from his own observations on sprouting seeds. The branches of the primary root are called secondary roots, and the branches of these are known as tertiary roots. Those roots which occur on the stem or in other unusual places are known as adventitious roots. The roots which form so readily on cuttings of willow, southernwood, tropeolum, French marigold, geranium (pelargonium), tradescaiitia, and many other plants, when placed in damp earth or water, are adventitious. 49, Aerial Roots. —While the roots of most familiar plants grow in the earth and‘are known as soil-roots, there are others which are formed in the air, called aerial roots. They serve various purposes: in some tropical air-plants (Fig. 18) they serve to fasten the plant to the tree on which it establishes itself, as well as to take in water which drips from branches and trunks above them, so that these plants require no soil and grow in mid-air suspended from trees, which serve them merely as supports ;?. many such 1To the plant the root is more important than the stem. The author has, however, treated the structure of the latter more fully than that of the root, mainly because the tissues are more varied in the stem and a moderate knowl- edge of the more complex anatomy of the stem will serve every purpose. “If it can be conveniently managed, the class will find it highly interesting and profitable to visit any greenhouse of considerable size, in which the aerial roots of orchids and aroids may be examined. 36 ROOTS 37 air-plants are grown in greenhouses. In such plants as the ivy (Fig. 15) the aerial roots (which are also adventitious) hold the plant to the wall or other surface up which it climbs. In the Indian corn (Fig. 14) roots are sent out from nodes at some dis- tance above the ground and ‘finally descend until they enter the ground. They serve both to anchor the cornstalk so as to enable it to resist the wind and to supply additional water to the plant.t They often produce no rootlets until they reach the ground. 50. Water-Roots. — Many plants, such as the willow, readily adapt their roots to live either in earth or in water, * - and some, like the little float- ing duckweed, regularly pro- duce roots which are adapted to live in water ‘ only. These water-roots often show large and \ distinct sheaths on the ends of the roots, as, for instance, in the so-called water-hyacinth. This plant is especially interesting for laboratory cultivation from the fact that Fig. 13. — Aerial § Roots of an Orchid.. 1 Specimens of the lower part of the cornstalk, with ordinary roots and aerial roots, should be dried and kept for class study. 38 FOUNDATIONS OF BOTANY t 1 I di | . vw | Indian Corn, showing Aerial Roots (‘ Brace-Roots ”’), a,c, internodes of the stem ; 8, d, e, f', nodes of various age bearing roots. Most of these started as aerial roots, but all except those from 6 have now reached the earth, ROOTS ES) it may readily be transferred to moderately damp soil, and that the whole plant presents curious modifications when made to grow in earth instead of water. 51. Parasitic Roots.:— The dodder, the mistletoe, and a good many other parasites, live upon nourishment which they steal from other plants, called hosts. The parasitic Fig. 15. — Aerial Adventitious Roots of the Ivy. roots, or haustoria, form the most intimate connections with the interior portions of the stem or the root, as the case may be, of the host-plant on which the parasite fastens itself. In the dodder, as is shown in Fig. 16, it is most inter- esting to notice how admirably the seedling parasite is adapted to the conditions under which it is to live. Rooted 1See Kerner and Oliver’s Natural History of Plants, Vol. I, pp. 171-213, 40 FOUNDATIONS OF BOTANY at first in the ground, it develops a slender, leafless stem, which, leaning this way and that, no sooner comes into Fic. 16. — Dodder, growing upon a Golden-Rod Stem, 8, seedling dodder plants, growing in earth; h, stem of host; r, haustoria or parasitic roots of dodder ; J, scale-like leaves. .4, magnified section of a por- tion of willow stem, showing penetration of haustoria. permanent contact with a congenial host than it produces haustoria at many points, gives up further growth in its ROOTS 41 soil-roots, and grows rapidly on the strength of the sup- plies of ready-made sap which it obtains from the host. 52. Forms of Roots. — The primary root is that which proceeds like a downward prolongation directly from the lower end of the hypocotyl. In many cases the mature root- system of the plant contains one main root much larger than any of its branches. This is called a taproot (Fig. 17). Such a root, if much thickened, would assume the form Fie. 17.— A Taproot. Fia, 18. — Fibrous Roots. Fia. 19.— Fascicled Roots. shown in the carrot, parsnip, beet, turnip, salsify, or radish, and is called.a fleshy root. Some plants produce multiple primary roots, that is, a cluster proceeding from the lower end of the hypocotyl at the outset. If such roots become thickened, like those of the sweet potato and the dahlia (Fig. 19), they are known as fascicled roots. Roots of grasses, etc., are thread-like, and known as fibrous roots (Fig. 18). 53. General Structure of Roots. — The structure of the very young root can be partially made out by examining 42 FOUNDATIONS OF BOTANY the entire root with a moderate magnifying power, since the whole is sufficiently translucent to allow the interior as well as the exterior portion to be studied while the root is still alive and growing. Place some vigorous cuttings of tradescantia or Zebrina, which can usually be obtained of a gardener or florist, in a beaker or jar of water.) The jar should be as thin and trans- parent as possible, and it is well to get a flat- sided rather than a cylindrical one. Leave the jar of cuttings in @ sunny, warm place. As soon as roots have developed at the nodes and reached the length of three-quarters of an inch or more, arrange a microscope in a hori- zontal position (see Handbook), and exam- ine the tip and adjacent portion of one of the young roots with a powér of from twelve to twenty diameters. Fic. 20.—Lengthwise Section (somewhat diagram- Note: matic) through Root-Tip of Indian Corn. x about 130. (a) The roo t-eap, W, root-eap ; i, younger part of cap ; z, dead cells sepa- of loosel y rating from cap ; s, growing point; 0, epidermis; p’, intermediate layer between epidermis and central attached cells. cylinder; p, central cylinder; d, layer from which (0) The central the root-cap originates. cylinder. 1 If the tradescantia or Zebrina cannot be obtained, roots of seedlings of oats, wheat, or barley, or of red-clover seedlings raised in a large covered cell on a microscope slide, may be used. ROOTS 43 (¢) The cortical portion, a tubular part enclosing the solid central cylinder. (@) The root-hairs, which cover some parts of the outer layer of ' the cortical portion very thickly. Observe particularly how far toward the tip of the root the root-hairs extend, -and where the youngest ones are found. Make a drawing to illustrate all the points above suggested (a,b, c,d). Compare your drawing with Fig. 20. Make a careful study of longitudinal sections through the centers of the tips of very young roots of the hyacinth or the Chinese sacred lily. Sketch one section and compare the sketch with Fig. 20. Make a study of the roots. of any of the common duckweeds, growing in nutrient solution in a jar of water under a bell-glass, and note the curious root-pockets which here take the place of root-caps. 54. Details of Root-Structure.— The plan on which the young root is built has been outlined in Sect. 538. o NY 86 a? CAoame 2 © Se\ (2 Ho 9 cAne @ PP OE ® 9 @ \ ae So As 3 s 2 o ee as fo a of6 => 9 Bo oe @e™ = Ze 90 ne Sat’ “So Nt Yo =e *F apes 6 : “Br oF, {j= d Oe'\s ~o0® = Ze = . cs 999.0 9 AS og 2° Sy 9, : , %O @ 9% = 2 0° 3 . ® F 0° ¥ @ =. : © Bee ee a 2? e C 2 st Fig. 116. — Vertical Section of the Leaf of the Beet. (Much magnified.) e, epidermis ; p, palisade-cells (and similar elongated cells) ; r, cells filled with red cell sap ; i, intercellular spaces; a, air spaces communicating with the stomata; st, stomata, or breathing pores. 1 The teacher may measure the size with the camera lucida. 152 FOUNDATIONS OF BOTANY somewhat kidney-shaped and become more or less curved as they are fuller or less full of water (see Sect. 170). 162, Calculation of Number of Stomata per Unit of Area. —In order to get a fairly exact-idea of the number of stomata on a unit of leaf-surface, the most convenient Fig. 117. —Epidermis of Leaf of Althea. (Much magnified.) A, from upper surface; B, from lower surface. h, star-shaped compound hairs; st, stomata; p, upper ends of palisade-cells, seen through the epidermis ; e, cells of epidermis, plan is to make use of a photo- micrograph. The bromide enlarge- ment No. 12 of the Tower series represents about a twenty-five- hundredth of a square inch of the lower epidermis of the cyclamen leaf, magnified until it is about fifteen inches square. Count the number of stomata on the entire photograph, then calculate the number of stomata on a square inch of the surface of this leaf. If a cyclamen plant has twelve leaves, each with an average area of six square inches, calculate the number of stomata of the lower epidermis of all the leaves taken together. MINUTE STRUCTURE OF LEAVES 153 In the case of an apple tree, where the epidermis of the lower surface of the leaf contains about 24,000 stomata to the square inch, or the black walnut, with nearly 300,000 to the square inch, the total number on a tree is incon- ceivably large. 163. Uses of the Parts examined. — It will be most con- venient to discuss the uses of the parts of the leaf a little later, but it will make matters simpler to state at once that the epi- dermis serves as a mechanical protec- tion to the parts yy. 118,A Stomaof Thyme. (Greatly magnified.) vo , i 52, - beneath and pre A, section at right angles to surface of leaf; B, sur. . face view of stoma. cu, cuticle; g, guard-cells; vents excessive 8, stoma; e, epidermal cells; a, air chamber ; evaporation, that e, cells of spongy parenchyma with grains of the palisade-cells ee (which it may not be easy to make out very clearly in a roughly prepared section) hold large quantities of the green coloring matter of the leaf in a position where it can receive enough but not too much sunlight, and the. cells of the spongy parenchyma share the work of the palisade- cells, besides evaporating much water. The stomata admit air to the interior of the leaf (where the air spaces 154 FOUNDATIONS OF BOTANY serve to store and to distribute it), they allow oxygen and carbonic acid gas to escape, and, above all, they regu- late the evaporation of water from the plant. 164, Leaf of “‘India-Rubber Plant.’?!— Study with the micro- scope, as the lily leaf was studied, make the same set of sketches, note the differences in structure between the two leaves, and try to discover their meaning. How does the epidermis of the two leaves compare? Which has the larger stomata? Which would better withstand great heat and long drought? 165. Chlorophyll as found in the Leaf. — Slice off a little of the epidermis from some such soft, pulpy leaf as Fia. 119.— Section through Lower Epidermis of Leaf of India-Rubber Plant (Ficus elastica). (Magnified 330 diameters.) v, opening of pit; p, pit leading to stoma; s, stoma, with two guard-cells; w, water-storage cells of epidermis ; a, an air space; around and above the air spaces are cells of the spongy parenchyma. that of the common field sorrel,? live-for-ever, or spinach ; scrape from the exposed portion a very little of the green pulp ; examine with the highest power attainable with your microscope, and sketch several cells. 1 Ficus elastica, a kind of fig tree. 2 Rumex Acetoseila. MINUTE STRUCTURE OF LEAVES 155 Notice that the green coloring matter is not uniformly distributed, but that it is collected into little particles called chlorophyll bodies (Fig. 120, p). 166. Woody Tissue in Leaves.— The veins of leaves consist of fibro-vascular bundles containing wood and vessels much like those of the stem of the plant. Indeed, these bundles in the leaf are continuous with those of the stem, and consist a of portions of the latter, looking , --~ e as if unraveled, which pass * outward and upward from the stem into the leaf under the name of leaf-traces. ¢ These traverse the peti- £9 ole often in a somewhat — irregular fashion. Fig. 120.—Termination Ss* of a Vein in a Leaf. F EXPERIMENT XXVIII (Mamiiaad: ancne fa diameters.) Passage of Water from aa fs mutatis v, Spirally 1¢Kened Ce. Stem to Leaf.—Place a ‘of the vein; p, paren- freshly cut leafy shoot of some ¢hyma-cells of the s spongy interior of the plant with large thin leaves, leaf, with chlorophyll such as Hydrangea hortensia, aa my nucleated in eosin solution for a few minutes. As soon as the leaves show a decided reddening, pull some of them off and sketch the red stains on the scars thus made. What does this show? 167. Experimental Study of Functions of Leaves. — The most interesting and profitable way in which to find out what work leaves do for the plant is by experimenting upon them. Much that relates to the uses of leaves is « 156 FOUNDATIONS OF BOTANY not readily shown in ordinary class-room experiments, but some things can readily be demonstrated in the experi- ments which follow. EXPERIMENT XXTX Transpiration. — Take two twigs or leafy shoots of any thin-leafed plant ;1 cover the cut end of each stem with a bit of grafting wax? to prevent evaporation from the cut surface. Put one shoot into a fruit jar, screw the top on, and leave in a warm room; put the other beside it, and allow both to remain some hours. Examine the relative appearance of the two, as regards wilting, at the end of the time. Which shoot has lost most? Why? Has the one in the fruit jar lost any water? To answer this question, put the jar (without opening it) into a refrigerator; or, if the weather is cold, put it out of doors for a few minutes, and examine the appearance of the inside of the jar. What does this show ?® 168. Uses of the Epidermis.t— The epidermis, by its toughness, tends to prevent mechanical injuries to the leaf, and after the filling up of a part of its outer por- tion with a corky substance it greatly diminishes the loss of water from the general surface. This process of becom- ing filled with cork substance, suberin (or a substance of similar properties known as cutin) is essential to the safety of leaves or of young stems which have to with- stand heat and dryness. The corky or cutinized cell- wall is waterproof, while ordinary cellulose allows water 1 Hydrangea, squash, melon, or cucumber is best; many other kinds will answer very well. 2 Grafting wax may be bought of nurserymen or seedsmen. 8 If the student is in doubt whether the jar filled with ordinary air might not behave in the same way, the question may be readily answered by putting a sealed jar of air into the refrigerator. 4 See Kerner and Oliver’s Natural History of Plants, Vol. I, pp. 273-362. MINUTE STRUCTURE OF LEAVES 157 to soak through it with ease. Merely examining sections of the various kinds of epidermis will not give nearly as good an idea of their properties as can be obtained by studying the behavior during severe droughts of plants which have strongly cutinized surfaces and of those which have not. Fig. 121, however, may convey some notion of the difference between the two kinds of structure. In most c. cases, as in the india- ring eee T rubber tree, the ex- if q, i f ternal epidermal cells ( } («| (and often two or TN three layers of cells beneath these) are - —————_——__ _filled with water, and B 4 thus serve as reser- <—~ fr Par N fo voirs from which the Fig. 121. — Unequal Development of Cuticle outer parts of the leaf By Res ronan es 4 A, epidermis of Butcher’s Broom (Ruscus); B, and the stem are at epidermis of sunflower; c, cuticle; e, epi- times supplied. dermis-cells. In many cases, noticeably in the cabbage, the epidermis is covered with a waxy coating, which doubtless increases the power of the leaf to retain needed moisture, and which certainly prevents rain or dew from covering the leaf-surfaces, especially the lower surfaces, so as to hinder the operation of the stomata. Many common plants, like the meadow rue and the nasturtium, possess this power to shed water to such a degree that the under surface of the leaf is hardly wet at all when immersed in water. The air-bubbles on such leaves give them a silvery appearance when held under water. 158 FOUNDATIONS OF BOTANY 169. Hairs on Leaves. — Many kinds of leaves are more or less hairy or downy, as those of the mullein, the “mullein pink,” many cinquefoils, and other common plants. In some instances this hairiness may be a protec- tion against snails or other small leaf-eating animals, but in other cases it seems to be pretty clear that the woolli- ness (so often confined to the under surface) is to lessen the loss of water through the stomata. The Labrador tea is an excellent example of a plant, with a densely woolly coating on the lower surface of the leaf. The leaves, too, are partly rolled up (see Fig. 224), with the upper surface outward, so as to give the lower surface a sort of deeply grooved form, and on the lower surface all of the stomata are placed. This plant, like some others with the same characteristics, ranges far north into. . regions where the temperature, even during summer, often falls so low that absorption of water by the roots ceases, since it has been shown that this nearly stops a little above the freezing point of water (see Exp. XVII). Exposed to cold, dry winds, the plant would then often be killed by complete drying if it were not for the pro- tection afforded by the woolly, channeled under surfaces of the leaves.t 170. Operation of the Stomata.— The stomata serve to admit air to the interior of the leaf, and to allow moisture, in the form of vapor, to pass out of it. They do this not in a passive way, as so many mere holes in the epidermis might, but to a considerable extent they regulate the rapidity of transpiration, opening more widely in damp weather and closing in dry weather. The opening is 1 This adaptation is sufficiently interesting for class study. ence teeamninn tence ac Ea nner Ray aM tn cc, Puate IV. — A Cypress Swamp FUNCTIONS OF LEAVES 159 caused by each of the guard-cells bending into a more kidney-like form than usual, and the closing by a straight- ening out of the guard-cells. The under side of the leaf, free from palisade-cells, abounding in intercellular spaces, and pretty well protected from becoming covered with rain or dew, is especially adapted for the working of the stomata, and accordingly we usually find them in much greater numbers on the lower surface. On the other hand, the little flowerless plants known as liverworts, which lie prostrate on the ground, have their stomata on the upper surface, and so do the leaves of pond lilies, which lie flat on the water. In those leaves which stand with their edges nearly vertical, the stomata are dis- tributed somewhat equally on both surfaces. Stomata occur in the epidermis of young stems, being replaced later by the lenticels. Those plants which, like the cacti, have no ordinary-leaves, transpire through the stomata scattered over their general surfaces. The health of the plant depends largely on the proper working condition of the stomata, and one reason why plants in cities often fail to thrive is that the stomata become choked with dust and soot. In some plants, as the oleander, provision is made for the exclusion of dust by a fringe of hairs about the opening of each stoma. If the stomata were to become filled with water, their activ- ity would cease until they were freed from it; hence many plants have their leaves, especially the under sur- faces, protected by a coating of wax which sheds water. 171. Measurement of Transpiration. — We have already proved that water is lost by the leaves, but it is worth while to perform a careful experiment to reduce our 160 FOUNDATIONS OF BOTANY knowledge to an exact form, to learn how much water a given plant transpires under certain conditions. It is also desirable to find out whether different kinds of plants transpire alike, and what changes in the temperature, the dampness of the air, the brightness of the light, to which a plant is exposed, have to do with its transpiration. Another experiment will show whether both sides of a leaf transpire alike. EXPERIMENT XXX Amount of Water lost by Transpiration. — Procure a thrifty hydran- gea+ and a small “india-rubber plant,”? each growing in a small flower-pot, and with the number of square inches of leaf-surface in the two plants not too widely different. Calculate the area of the leaf-surface for each plant, by dividing the surface of a piece of tracing cloth into a series of squares one-half inch on a side, holding an average leaf of each plant against this and counting the number of squares and parts of squares covered by the leaf. ‘> Or weigh a square inch of tinfoil on a very delicate balance, cut out a piece of the same kind of tinfoil of the size of an average Fig. 122.— A Hydrangea pottedina = Jeaf, weigh this and calculate the Seu Nee eerie leaf-area from the two weights. This area, multiplied by the number of leaves for each plant, will give approximately the total evaporating surface for each. i Transfer each plant to a glass battery jar of suitable size. Cover 1 The common species of the greenhouses, Hydrangea Hortensia. 2 This is really a fig, Ficus elastica. FUNCTIONS OF LEAVES 161 the jar with a piece of sheet lead, slit to admit the stem of the plant, invert the jar and seal the lead to the glass with a hot mixture of beeswax and rosin. Seal up the slit and the opening about the stem with grafting wax. A thistle-tube, such as is used by chem- ists, is also to be inserted, as shown in Fig.122.1 The mouth of this may be kept corked when the tube is not in use for watering. Water each plant moderately and weigh the plants separately on a balance that is sensitive to one-fifth gram. Record the weights, allow the plants to stand in a sunny, warm room for twenty-four hours and reweigh. Add to each plant just the amount of water which is lost,? and continue the experiment in the same manner for several days so as to ascertain, if possible, the effect upon transpiration of varying amounts of water in the atmosphere. Calculate the average loss per 100 square inches of leaf-surface for each plant throughout the whole course of the experiment. Divide the greater loss by the lesser to find their ratio. Find the ratio of each plant’s greatest loss per day to its least loss per day, and by comparing these ratios decide which transpires more regularly. Try the effect of supplying very little water to each, so that the hydrangea will begin to droop, and see whether this changes the relative amount of transpiration for the two plants. Vary the con- ditions of the experiment for a day or two as regards temperature, and again for a day or two as regards light, and note the effect upon the amount of transpiration. The structure of the fig (India-rubber plant) leaf has already been studied. That of the hydrangea is looser in texture and more like the leaf of the lily or the beet (Fig. 116). What light does the structure throw on the results of the pre- ceding experiment ? 1 It will be much more convenient to tie the hydrangea if one has been chosen that has but a single main stem. Instead of the hydrangea, the com- mon cineraria, Senecio cruentus, does very well. 2 The addition of known amounts of water may be made most conveniently by measuring it in a cylindrical graduate. 162 FOUNDATIONS OF BOTANY EXPERIMENT XXXI Through which Side of a Leaf of the India-Rubber Plant does Tran- spiration occur ?— The student may already have found (Sect. 164) that there are no stomata on the upper surface of the fig leaf which he studied. That fact makes this leaf an excellent one by means of which to study the relation of stomata to transpiration. Take two large, sound rubber-plant leaves, cut off pretty close to the stem of the plant. Slip over the cut end of the pétiole of each leaf a piece of small rubber tubing, wire this on, leaving about half of it free, then double the free end over and wire tightly, so as to make the covering moisture-proof. Warm some vaseline or grafting wax until it is almost liquid, and spread a thin layer of it smoothly over the upper surface of one leaf and the lower surface of the other. Hang both up in a sunny place in the laboratory and watch them for a month or more. What difference in the appearance of the two leaves’ becomes evident? What does the experiment prove? 172, Endurance of Drought by Plants. — Plants in a wild state have to live under extremely different conditions as regards water supply (see Chapter XXIV). Observation of growing plants during a long drought will quickly show how differently the various species of a region bear the hardships due to a scanty supply of moisture. It is still easier, however, to subject some plants to an artificial drought and watch their condition. EXPERIMENT XXXII Resistance to Drought. — Procure at least one plant from each of these groups : . Group I. Melon-cactus (Echinocactus or Mamillaria), prickly pear cactus. Group II. Aloe, Cotyledon (often called Echeveria), houseleek. FUNCTIONS OF LEAVES 163 Group IIL. Live-for-ever (Sedum Telephium), Bryophyllum, English ivy, “ivy-leafed geranium,” (Pelargonium peltatum), or any of the fleshy-leafed begonias. Group IV. Hydrangea (H. Hortensia), squash or cucumber, sun- flower. The plants should be growing in pots and well rooted. Water them well and then put them all in a warm, sunny place. Note the appearance of all the plants at the end of twenty-four hours. If any are wilting badly, water them. Keep on with the experiment, in no case watering any plant or set of plants until it has wilted a good deal. Record the observations in such a way as to show just how long a time it took each plant to begin to wilt from the time when the experiment began. If any hold out more than a monthy they may aiterwards be examined at intervals of a week, to save the time required for daily observations. If possible, account by the struc- ture of the plants for some of the differences observed. Try to learn the native country of each plant used and the soil or exposure natural to it. 173. Course traversed by Water through the Leaf.— The same plan that was adopted to trace the course of water in the stem (Exp. X XI) may be followed to discover its path through the leaf. EXPERIMENT XXXII Rise of Sap in Leaves. — Put the freshly cut ends of the petioles of several thin leaves of different kinds into small glasses, each con- taining eosin solution to the depth of one-quarter inch or more. Allow them to stand for half an hour, and examine them by holding up to the light and looking through them to see into what parts the eosin solution has risen. Allow some of the leaves to remain as much as twelve hours, and examine them again. The red-stained portions of the leaf mark the lines along which, under natural con- ditions, sap rises into it. Cut across (near the petiole or midrib ends) all the principal veins of some kind of large, thin leaf. Then cut off the petiole and at once stand the cut end, to which the blade 164 FOUNDATIONS OF BOTANY is attached, in eosin solution. Repeat with another leaf and stand in water. What do the results teach? 174, Total Amount of Transpiration. — In order to pre- vent wilting, the rise of sap during the life of the leaf must have kept pace with the evaporation from its sur- face. The total amount of water that travels through the roots, stems, and leaves of most seed-plants during their lifetime is large, relative to the weight of the plant itself. During 1738 days of growth a corn-plant has been found to give off nearly 381 pounds of water. During 140 days of growth a sunflower-plant gave off about 145 pounds. A grass-plant has been found to give off its own weight of water every twenty-four hours in hot, dry summer weather. This would make about 6} tons per acre every twenty-four hours for an ordinary grass-field, or rather over 2200 pounds of water from a field 50 x 150 feet, that is, not larger than a good-sized city lot. Calculations based on observations made by the Austrian forest experiment stations showed that a birch tree with 200,000 leaves, standing in open ground, transpired on hot summer days from 700 to 900 pounds, while at other times the amount of transpiration “was probably not more than 18 to 20 pounds.! These large amounts of water are absorbed, carried through the tissues of the plant, and then given off by the leaves because the plant-food contained in the soil-water is in a condition so diluted that great quantities of water must be taken in order to secure enough of the mineral and other substances which the plant demands from the soil. Active transpiration may also have other causes. 1 See B. E. Fernow’s discussion in Report of Division of Forestry of U. 8. Department of Agriculture, 1889, FUNCTIONS OF LEAVES 165 Meadow hay contains about two per cent of potash, or 2000 parts in 100,000, while the soil-water of a good soil does not contain more than one-half part in 100,000 parts. It would therefore take 4000 tons of such water to furnish the potash for one ton of ‘hay. The water which the root-hairs take up must, however, contain far more potash than is assumed in the calculation above given, so that the amount of water actually used in the growth of a ton of hay cannot be much more than 260 tons.! 175, Accumulation of Mineral Matter in the Leaf. — Just as a deposit of salt is found in the bottom of a seaside pool of salt water which has been dried up by the sun, so old leaves are found to be loaded with mineral matter, left behind as the sap drawn up from the roots is evaporated through the stomata. A bonfire of leaves makes a sur- prisingly large heap of ashes. An abundant constituent of the ashes of burnt leaves is silica, a substance chemic- ally the same as sand. This the plant is forced to absorb along with the potash, compounds of phosphorus, and other useful substances contained in the soil-water; but since the silica is of hardly any value to most plants, it often accumulates in the leaf as so much refuse. Lime is much more useful to the plant than silica, but a far larger quan- tity of it is absorbed than is needed; hence it, too, accu- mulates in the leaf. 176. Nutrition, Metabolism.2— The manufacture of the more complex plant-foods, starch, sugar, and so on, from 1 See the article, ‘‘ Water as a Factor in the Growth of Plants,” by B. T. Galloway and Albert F. Woods, Year-Book of U. S. Department of Agriculture, 1894, 2See Kerner and Oliver’s Natural History of Plants, Vol. I, pp. 371-483. Also Pfeffer’s Physiology of Plants, translated by Ewart, Chapter VIII. 166 FOUNDATIONS OF BOTANY the raw materials which are afforded by the earth and air and all the steps of the processes by which these foods are used in the life and growth of the plant are together known as its nutrition. When we think more of the chemical side of nutrition than of its relation to plant-life, we call any of the changes or all of them metabolism, which means simply chemical transformation in living tissues. There are two main classes of metabolism — the constructive kind, which embraces those changes which build up more com- plicated substances out of simpler ones (Sect. 179), and the destructive kind, the reverse of the former (Sect. 184). A good many references to cases of plant metabolism have been made in earlier chapters, but the subject comes up in more detail in connection with the study of the work of leaves than anywhere else, because the feeding which the ordinary seed-plant does is very largely done in and by its leaves. 177. Details of the Work of the Leaf. — A leaf has four functions to perform: (1) Starch-making; (2) assimila- tion; (8) excretion of water ; (4) respiration. 178. Absorption of Carbon Dioxide and Removal of its Carbon. — Carbon dioxide is a constant ingredient of the atmosphere, usually occurring in the proportion of about four parts in every 10,000 of air or one twenty-fifth of one per cent. It is a colorless gas, a compound of two simple substances or elements, carbon and oxygen, the former familiar to us in the forms of charcoal and graphite, the latter occurring as the active constituent of air. 1JIn many works on Botany (1) and (2) are both compounded under the term assimilation. Many botanists (most of the American ones) apply the name photosynthesis or photosyntax to the starch-making process, but these names are not wholly satisfactory, and perhaps it is as well (as suggested by Professor Atkinson) to name the process from its result. FUNCTIONS OF LEAVES , 167 Carbon dioxide is produced in immense quantities by the decay of vegetable and animal matter, by the respira- tion of animals, and by all fires in which wood, coal, gas, or petroleum is burned. Green leaves and the green parts of plants, when they contain a suitable amount of potassium salts, have the power of removing carbon dioxide from the air (or in the case of some aquatic plants from water in which it is dissolved), retaining its carbon and setting free part or all of the oxygen. This process is an important part of the work done by the plant in making over raw materials into food from which it forms its own substance. EXPERIMENT XXXIV Oxygen-Making in Sunlight.— Place a green aquatic plant in a glass jar full of ice-cold fresh water, in front of a sunny window.! Place a thermometer in the jar, watch the rise of temperature, aud note at what point you first observe the formation of oxygen bub- bles. Remove to a dark closet for a few minutes and examine by lamplight, to see whether the rise of bubbles still continues. This-gas may be shown to be oxygen by collecting some of it in a small inverted test-tube filled with water and thrusting the glowing coal of a match just blown out into the gas. It is not, however, very easy to do this satisfac- torily before the class. Repeat the experiment, using water which has been well boiled and then quickly cooled. Boiling removes all the dissolved gases from water, and they are not re-dissolved in any considerable quantity for many hours. 1 Elodea, Myriophyllum, Chrysosplenium, Potamogeton, Fontinalis, any of the green aquatic flowering plants, or even the common confervaceous plants, known as pond-scum or “ frog-spit,” will do for this experiment. 168 FOUNDATIONS OF BOTANY Ordinary air, containing a known per cent of carbon dioxide, if passed very slowly over the foliage of a plant covered with a bell- glass and placed in full sunlight, will, if tested chemically, on com- ing out of the bell-glass be found to have lost a little of its carbon dioxide. The pot in which the plant grows must be covered with a lid, closely sealed on, to prevent air charged with carbon dioxide (as the air of the soil is apt to be) from rising into the bell-glass. 179. Disposition made of the Absorbed Carbon Dioxide. — It would lead the student too far into the chemistry of botany to ask him to follow out in detail the changes by which carbon dioxide lets go part at least of its oxygen and gives its remaining portions, namely, the carbon, and perhaps part of its oxygen, to build up the substance of the plant. Starch is composed of three elements: hydro- gen (a colorless, inflammable gas, the lightest of known substances), carbon, and oxygen. Water is composed largely of hydrogen, and, therefore, carbon dioxide and water contain all the elements necessary for making starch. The chemist cannot put these elements together to form starch, but the plant can do it, and at suitable temperatures starch-making goes on constantly in the green parts of plants when exposed to sunlight and supplied with water and carbon dioxide.! The seat of the manufacture is in the chlorophyll bodies, and protoplasm is without doubt the manufacturer, but the process is not understood by chemists or botanists. No carbon dioxide can be taken up and used by plants growing in the dark, nor in an atmosphere con- taining only carbon dioxide, even in the light. 1 Very likely the plant makes sugar first of all and then rapidly changes this into starch. However that may be, the first kind of food made in the leaf and retained long enough to be found there by ordinary tests is starch. See Pfeffer’s Physiology of Plants, translated by Ewart, Vol. I, pp. 317, 318. Puate V. — A Saprophyte, Indian Pipe FUNCTIONS OF LEAVES 169 A very good comparison of: the leaf to a mill has been made as follows !: The mill: : Palisade-cells and underlying cells of the leaf. Raw material used: Carbon dioxide, water. Milling apparatus : Chlorophyll grains. Energy by which the mill is run: Sunlight. Manufactured product : Starch. Waste product : Oxygen. 180. Plants Destitute of Chlorophyll not Starch-Makers. — Aside from the fact that newly formed starch grains are first found in the chlorophyll bodies of the leaf and the green layer of the bark, one of the best evidences of the intimate relation of chlorophyll to starch-making is derived from the fact that plants which contain no chloro- phyll cannot make starch from water and carbon dioxide. Parasites, like the dodder, which are nearly destitute of green coloring matter, cannot do this; neither can sapro- phytes or plants which live on decaying or fermenting organic matter, animal or vegetable. Most saprophytes, like the moulds, toadstools, and yeast, are flowerless plants of low organization, but there are a few (such as the Indian pipe (Plate V), which flourishes on rotten wood or among decaying leaves) that bear flowers and seeds. 181. Detection of Starch in Leaves. — Starch may be found in abundance by microscopical examination of the green parts of growing leaves, or its presence may be shown by testing the whole leaf with iodine solution. 1 By Professor George L. Goodale. 170 FOUNDATIONS OF BOTANY EXPERIMENT XXXV Occurrence of Starch in Nasturtium Leaves. — Toward the close of a very sunny day collect some bean leaves or leaves of nasturtium (Tropeolum). - Boil these in water for a few minutes, to kill the protoplasmic contents of the cells and to soften and swell the starch grains. Soak the leaves, after boiling, in strong alcohol for a day or two, to dissolve out the chlorophyll, which would otherwise make it diffi- cult to see the blue color of the starch test, if any were obtained. Rinse out the alcohol with plenty of water and then place the leaves for ten or fifteen minutes in a solution of iodine, rinse off with water and note what portions of the leaf, if any, show the presence of starch. EXPERIMENT XXXVI Consumption of Starch in Nasturtium (Tropeolum) Leaves. —Select some healthy leaves of Tropeolum on a plant growing vigorously indoors or, still better, in the Fic. 123.—Leaf of Tropzo- : . lum partly covered with open air. Shut off the sunlight from Disks of Cork and ex- parts of. the selected leaves (which are to cee be left on the plant and as little injured as may be) by pinning circular disks of cork on opposite sides of the leaf, as shown in Fig. 123. On the afternoon of the next day remove these leaves from the plant and treat as described in the preceding experiment, taking especial pains to get rid of all the chlorophyll by changing the alcohol as many times as may be neces- sary. What does this experiment show in regard to the consump- tion of starch in the leaf? What has caused its disappearance? 182. Rate at which Starch is manufactured. — The amount of starch made in a day by any given area of 1 The leaves, collected as above described, may, after boiling, be kept in alcohol for winter use. They also make excellent material for the micro- scopical study of starch in the leaf. FUNCTIONS OF LEAVES 171 foliage must depend on the kind of leaves, the tempera- ture of the air, the intensity of the sunlight, and some other circumstances. Sunflower leaves and pumpkin or squash leaves have been found to manufacture starch at about the same rate. In a summer day fifteen hours long they can make nearly three-quarters of an ounce of starch for each square yard of leaf-surface. A full-grown squash leaf has an area of about one and one-eighth square feet, and a plant may bear as many as 100 leaves. What would be the daily starch-making capacity of such a plant?! 183. Assimilation. — From the starch in the leaf, grape- sugar or malt-sugar is readily formed, and some of this in turn is apparently combined on the spot with nitrogen, sulphur, and phosphorus. These elements are derived from nitrates, sulphates, and phosphates, taken up in a dissolved condition by the roots of the plant and trans- ported to the leaves. The details of the process are not understood, but the result of the combination of the sugars or similar substances with suitable (very minute) proportions of nitrogen, sulphur, and phosphorus is to form complex nitrogen compounds. These are not pre- cisely of the same composition as the living protoplasm of plant-cells or as the reserve proteids stored in seeds (Sects. 14, 17), stems (Sect. 127), and other parts of plants, but are readily changed into protoplasm or proteid foods as necessity may demand. Assimilation is by no means confined to leaves ; indeed, most of it, as above suggested, must take place in other parts of the plant. For instance, the manufacture of the immense amounts ‘of cellulose, of cork, and of the com- 1 See Pfeffer’s Physiology of Plants, translated by Ewart, Vol. I, p. 324. 172 FOUNDATIONS OF BOTANY pound (lignin) characteristic of wood-fiber, that go to make up the main bulk of a large tree must be carried on in the roots, trunk, and.branches of the tree. 184, Digestive Metabolism. — Plant-food in order to be carried to the parts where it is needed must be dissolved, and this dissolving often involves a chemical change and is somewhat similar to digestion as it occurs in animals. The newly made starch in the leaf must be changed to a sugar or other substance soluble in water before it can be carried to the parts of the plant where it is to be stored or to rapidly growing parts where it is to be used for building material. On the other hand, starch, oil, and such insoluble proteids as are deposited in the outer por- tion of the kernel of wheat and other grains are extremely well adapted to serve as stored food, but on account of their insoluble nature are quite unfit to circulate through the tissues of the plant. The various kinds of sugar are not well adapted for storage, since they ferment easily in the presence of warmth and moisture if yeast-cells or suitable kinds of bacteria are present. Two important differences between starch-making in the green parts of plants and the non-constructive or the destructive type of metabolism should be carefully noticed. These latter kinds of metabolism go on in the dark as well as in the light and do not add to the total weight of the plant. 185. Excretion of Water and Respiration. — Enough has been said in Sect. 174 concerning the former of these pro- cesses. Respiration, or breathing in oxygen and giving off carbonic acid gas, is an operation which goes on con- stantly in plants, as it does in animals, and is necessary to FUNCTIONS OF LEAVES 173 their life. For, like animals, plants get the energy with which they do the work of assimilation, growth, reproduc- tion, and performing their movements from the oxidation of such combustible substances as oil, starch, and sugar. The amount of oxy- gen absorbed and of car- bonic acid given off is, however, so trifling com- pared with the amount of each gas passing in the opposite direction, while starch-making is going on in sunlight, that under such circum- stances it is difficult to observe the occurrence of respiration. In ordi- nary leafy plants the Fie. 124.—Cross-Section of Stem of Marestail leaves (throu gh their (Hippuris) with Air-Passages, a. stomata) are the principal organs for absorption of air, but much air passes into the plant through the lenticels of the bark. In partly submerged aquatics especial provisions are found for carrying the air absorbed by the leaves down to the submerged parts. This is accomplished in pond lilies by ventilating tubes which traverse the leaf-stalks length- wise. In many cases such channels run up and down the stem (Fig. 124). 1 The necessity of an air supply about the roots of the plant may be shown by filling the pot or jar in which the hydrangea was grown for the transpi- ration experiment perfectly full of water and noting the subsequent appear- ance of the plant at periods twelve to twenty-four hours apart. FOUNDATIONS OF BOTANY 174 ‘atqissod sv 039[dur00 sv Jeol OT} JO FIOM O44 Jo SurMoys og} Furyeu Jo esodind on io 919T PA}IOSUI SI Ing ‘ssoo0Id ofOqeIOUT v 4OU SI .1098M JO UOIJAIOXG Ul UO O8 YOY sessadoad oI[OqeyJoUL Jo soles OTOYM ey} JO WOI410 “so 4UBJIOdU SOUL 9} JO OUIOS SaDvIqUUA FI ING ‘szUBT [jews & sapntout A[WO s[qQea SITY FBT} PooysiapuN oq 04 SE AT 1 saomeysqns | ry yyrm porddus ‘ Taye (JOM Op 0} 9 pl ale “TAT[ JRaT 10 W1948 (surqyeorg) ‘sed ploe o1moqareg | 1amod ‘-a-2) AS10ug, SRO PuBereeny damian aon. 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T d -ureyu09 spunod. wsvyjdojoid SUIATT vor e[TUISsy TOS TOF SPIOWTT | "yoo puw rvsng 1 used suleys u9e13 eae Yqoreys pur resng eae Dire -ojoid yo AS1aus pure saavel jo SULyeU-ToIeIg pessed ‘uashxQ eplxolp woqIeD ‘qeoy pue WSTTUNg satpoq [Aqdor0[ 49 sLOodoud AISV A sLondoud Taagsy NO da.L0V SHONVLIsSadag NO aalvavo ADUUNA JO GNIM LVHA AG XO agiguvo AONDOV FO SAIVAa -VddV LVHA AG ssuaooud JO AKVN 1 Sesse001g 19q}Q PUY oToquJeW_ Jo AremUING Ie[NQeL ‘OST FUNCTIONS OF LEAVES 175 187. The Fall of the Leaf. — In the tropics trees retain most of their leaves the year round; a leaf occasionally falls, but no considerable portion of them drops at any one season.! The same statement holds true in regard to our cone-bearing evergreen trees, such as pines, spruces, and the like. But the impossibility of absorbing soil-water when the ground is at or near the freezing temperature (Exp. XVII) would cause the death, by drying up, of trees with broad leaf-surfaces in a northern winter. And in countries where there is much snowfall, most broad- leafed trees could not escape injury to their branches from overloading with snow, except by encountering winter storms in as close-reefed a condition as possible. For such reasons our common shrubs and forest trees (except the cone-bearing, narrow-leafed ones already mentioned) are mostly deciduous, that is they shed their leaves at the approach of winter. The fall of the leaf is preceded by important changes in the contents of its cells. EXPERIMENT XXXVII Does the Leaf vary in its Starch Contents at Different Seasons ? Collect in early summer some leaves of several kinds of trees and shrubs and -preserve them in alcohol. Collect others as they are beginning to drop from the trees in autumn and preserve them in the same way. Test some of each lot for starch as described in Sect. 181. What does the result indicate? Much of the sugary and protoplasmic contents of the leaf disappears before it falls.. These valuable materials 1 Except where there is a severe dry season. 176 FOUNDATIONS OF BOTANY have been absorbed by the branches and roots, to be used again the following spring. The separation of the leaf from the twig is accomplished by the formation of a layer of cork cells across the base of the petiole in such a way that the latter finally breaks off across the surface of the layer. A waterproof scar is thus already formed before the removal of the leaf, and there is no waste of sap dripping from the wound where the leaf- stalk has been removed, and no chance for moulds to attack the bark or wood and cause it to decay. In com- pound leaves each leaflet may become separated from the petiole, as is notably the case with the horse-chestnut leaf (Fig. 102). In woody monocotyledons, such as palms, the leaf-stalks do not commonly break squarely off at the base, but wither and leave projecting stumps on the stem (Plate VI). The brilliant coloration, yellow, scarlet, deep red, and purple, of autumn leaves is popularly but wrongly sup- posed to be due to the action of frost. It depends merely on the changes in the chlorophyll grains and the liquid cell-contents that accompany the withdrawal of the proteid material from the tissues of the leaf. The chlorophyll turns into a yellow insoluble substance after the valuable materials which accompany it have been taken away, and the cell sap at the same time may turn red. Frost per- haps hastens the break-up of the chlorophyll, but individual trees often show bright colors long before the first frost, and in very warm autumns most of the changes in the foli- age may come about before there has been any frost. 188. Tabular Review of Experiments. [Continue the table from Sect. 128.] Piatre VI. — Fan Palms FUNCTIONS OF LEAVES 177 189. Review Summary of Minute Structure of Leaves.! General structure, distribution of parenchyma, and prosenchyma Layers of tissue seen on a cross- sectin «ss Structure of epidermis Structure of stomata . Distribution of stomata Structure and distribution of chlorophyll bodies 190. Review Summary of Functions of Leaves. fibro-vascular bundles epidermis . stomata air spaces . palisade-cells . spongy parenchyma waxy coating . hairs from the air . from the soil . Principal uses of . Substances received by the leaf . Substances manufactured by the leaf . into the air {| into the stem Mineral substances accumulated in the leaf Statistics in regard to transpiration Statistics in regard to starch-making . Substances given off by the leaf 1 Illustrate with sketches and diagrams. CHAPTER XII PROTOPLASM AND ITS PROPERTIES 191. The Cell in its Simplest Form. — Sufficient has been said in the preceding chapters, and enough tissues have been microscopically studied, to make it pretty clear what vegetable cells, as they occur in flowering plants, are like. In Chapter XI, leaf-cells have been taken for granted and their work described in some detail. Before going further, it is worth while to consider the structure of an individual cell, and to see of what kinds of activity it is capable. In studying the minute anatomy of bark, wood, pith, and other tissues the attention is often directed to the cell-wall without much regard to the nature of the cell- contents. Yet the cell-wall is not the cell, any more than the lobster shell or the crayfish shell is the lobster or the crayfish. The contained protoplasm with its nucleus is the cell. The cell reduced to its lowest terms need not have a cell-wall, but may consist simply of a mass of proto- plasm, usually containing a portion of denser consistency than the main bulk,- known as the nucleus. Such cells, without a cell-wall, are not common in the vege- table world, but are frequently encountered among animals. 192. The Slime Moulds. One of the best examples of masses of naked protoplasm leading an individual existence 1 See Kerner and Oliver’s Natural History of Plants, Vol. I, pp. 21-51. 2 Sirasburger, Noll, Schenk, and Schimper’s Text-Book of Botany, pp. 50-52 and 302-305. Bie PROTOPLASM AND ITS PROPERTIES 179 is found in the slime moulds, which live upon rotten tan bark, decaying wood, and so on. These curious organ- isms have so many of the characteristics both of animals and of plants that they have been described in zodlogies under the former title and in botanies under the latter one. Perhaps it would not really be so absurd a state- ment as it might seem, to say that every slime mould leads the life of an animal during one period of its existence and of a plant at another period. At any rate, whatever their true nature, these little masses of unenclosed protoplasm illustrate admirably some of the most important properties of protoplasm. Slime moulds spring from minute bodies called spores (Fig. 125, a) which differ from the seeds of seed-plants not only in their microscopic size but still more in their lack of an embryo. The spores of slime moulds are capable, when kept dry, of preserving for many years their power of germination, but in the pres- ence of moisture and warmth they will germinate as soon a8 they are scattered. During the process of germination the spore swells, as shown at 6, and then bursts, discharging its protoplasmic contents, as seen atc and d. ‘This in a few minutes lengthens out and produces at one end a hair- like ciliwm, as shown at e,f,g. These ciliated bodies are called swarmspores, from their power of swimming freely about by the vibrating motion of the cilia. Every swarm- spore has at its ciliated end a nucleus, and at the other end a bubble-like object which gradually expands, quickly dis- appears, and then again expands. This contractile vacuole is commonly met with in animalcules, and increases the likeness between the slime moulds and many microscopic animals. The next change of the swarmspores is into an 180 FOUNDATIONS OF BOTANY Ameba form (so called from one of the most interesting and simplest of animals, the Amada, found on the surface of Fig. 125.— A Slime Mould. (a~m, inclusive, x 540 times, n x 90 times.) mud and the leaves of water plants). In this condition, as shown at A, 7, k, the spores creep about over the sur- face of the decaying vegetable material on which the PROTOPLASM AND ITS PROPERTIES 18] slime moulds live. Their movement is caused by a thrust- ing out of the semi-liquid protoplasm on one side of the mass, and a withdrawal of its substance from the other side. At length many ameba-shaped bodies unite, as at 1, to form a larger mass, m, which finally increases to the protoplasmic network shown at . This eventually col- lects into a roundish or egg-shaped firm body, inside of which a new crop of spores is produced. It is not easy to trace the manner in which the nourishment of these simple plants is taken. Probably they absorb it from the decay- ing matter upon which they live during their amceba-like period, and after they have formed the larger masses, n. 193. Characteristics of Living Protoplasm.! — The behav- ior of the slime moulds during their growth and transfor- mations, as just outlined, affords a fair idea of several of the remarkable powers which belong to living protoplasm, which have been summed up as follows: (1) The power to take up new material into its own substance (selective absorption). This is not merely a proc- ess of soaking up liquids, such as occurs when dry earth or a sponge is moistened. The protoplasmic lining of a root-hair, for example, selects ‘from the. soil-water some substances and rejects others (Sect. 65). (2) The ability to change certain substances into others of different chemical composition (metabolism, Sect. 176). Carbon dioxide and water, losing some oxygen in the process, are combined into starch; starch is changed into various kinds of sugar and these back into starch again; starch becomes converted into vegetable acids, into cellu- lose, or into oil; or the elements of starch are~combined 1 See Huxley’s Essays, Vol. I, essay on “‘ The Physical Basis of Life.” 182 FOUNDATIONS OF BOTANY with nitrogen to mezke various proteid compounds, either for immediate use or for reserve food. Many other com- plicated transformations occur. (8) The power to cast off waste or used-up material (exeretion). Getting rid of surplus water (Sect. 174) and of oxygen (Sect. 178) constitutes a very large part of the excretory work of plants. (4) The capacity for growth and the production of off- spring (reproduction). These are especially characteristic of living protoplasm. It is true that non-living objects may grow in a certain sense, as an icicle or a crystal of salt or of alum in a solution of its own material does. But growth by the process of taking suitable particles into the interior of the growing substance and arranging them into an orderly structure (Fig. 126) is possible only in the case of live protoplasm. (5) The possession of the power of originating move- ments not wholly and directly caused by any external impulse (automatic movements). Such, for instance, are the lashing movements of the cilia of the swarmspores of slime moulds, or the slow pendulum movements of Oscillatoria (Sect. 269), or the slow vibrating movements of the stipules of the “telegraph plant” (Desmodium), not uncommon in greenhouses. (6) The power of shrinking or closing up (contractility). This is illustrated by the action of the contractile vacuole of the slime moulds and of many animalcules and by all ‘the muscular movements of animals. (7) Sensitiveness when touched or otherwise disturbed, for instance, by a change of light or of temperature (erritability). ‘ PROTOPLASM AND ITS PROPERTIES 183 194. Nature and Occurrence of Irritability in Plants.t — Mention has already been made of the fact that certain parts of plants respond to suitable stimuli that is exciting Fic. 126. — Protoplasm in Ovule and Fruit of Snowberry (Symphoricarpus racemosus). A, cells from ovule, x 340; B, cells from an ovule further developed, x 340; C, D, cells from pulp of fruit, x 110; ”, nucleus ; p, protoplasm ; s, cell-sap. In the young and rapidly growing cells, A and B, the cell-sap is not present, or present only in:small quantities, while in the older cells, C and D, it occupies a large portion of the interior of the cell, causes. Geotropic movements (Sect. 70) are due to the response of roots or shoots to gravitation. These 1 See Strasburger, Noll, Schenk, and poeanene 8s Text-Book of Botany, pp. 160-162 and 269-274, 184 FOUNDATIONS OF BOTANY movements are due to unequal growth induced in the younger portions of the plant by the action of gravi- Fig. 127. — Stinging Hair of Nettle, with Nucleus. (Much. magnified.) The ar- rows show the direc- tion of the currents in the protoplasm. tation upon it. Other movements (of ordinary foliage leaves, of the floral leaves of many flowers, and of other parts of a few flowers) are produced by changes in the distention or turgescence of some of the cells in the organs which move and have nothing to do with growth. The closing of the leaves of insect-catching plants is briefly described in Sect. 410, and the “sleep” of leaves, due to movements of the pulvini, was described in Sect. 152. A few facts in regard to the opening and closing of flowers will be found in Sect. 440. The stimuli which cause movements of leaves or of the irritable parts of flowers are of several kinds. Light is the main cause which induces leaves to open from their night position to that usual in the daytime. In the case of flowers, it is sometimes light and sometimes warmth which causes them to open. Leaves which catch insects may be made to close by touching them, but the sensitive-plants, of which there are several kinds found in the United States, and a much more sensi- tive one in tropical America, all fold their leaflets, on being touched, at night. into the same position which they assume PROTOPLASM AND ITS PROPERTIES 185 195. Circulation of Protoplasm.— When confined by a cell-wall, protoplasm often manifests a beautiful and con- stant rotating movement, traveling incessantly up one side of the cell and down the other. A more complicated motion is the cireulation of protoplasm, shown in cells of ‘the jointed blue hairs in the flower of the common spider- wort and in the stinging hairs of the nettle (Fig. 127). The thin cell-wall of each hair is lined with a protoplasmic layer in which are seen many irregular, thread-like cur- rents, marked by the movements of the granules, of which the protoplasmic layer is full. 1 See Huxley and Martin’s Elementary Biology, under Chara. CHAPTER XIII INFLORESCENCE, OR ARRANGEMENT OF FLOWERS ‘ ON THE STEM 196. Regular Positions for Flower-Buds. — Flower-buds, like leaf-buds, occur regularly either in the axils of leaves or at the end of the stem or branch and are therefore either axillary or terminal. 197. Axillary and Solitary Flowers; Indeterminate Inflorescence. — The simplest possible arrangement for flowers which-arise from the axils of leaves is to have a single flower spring’ from each leaf-axil. Fig. 128 shows how this plan appears in a plant with opposite leaves. As long as the stem continues to grow, the production of new leaves may be followed by that of new \ ‘p Fig. 128.— Axillary and Fic. 129.—Raceme of a Solitary Flowers of Common Red Currant. CAI@ S Pimpernel. DP, peduncle ; p’, pedicel ; br, bract. flowers. Since there is no definite limit to the number of flowers which may appear in this way, the mode of flowering just described (with many others of the same general character) is known as indeterminate inflorescence. 186 ARRANGEMENT OF FLOWERS ON THE STEM 187 198. The Racemes and Related Forms. — If the leaves along the stem were to become very much dwarfed and the Fie. 130.— Simple Umbel of Cherry. flowers brought closer together, as they frequently are, a kind of flower-cluster like that of the currant (Fig. 129) or the lily- of-the-valley would result. Such an. inflorescence is called a ra- ceme; the main flower-stalk is known as the pedunele ; the little individual flower-stalks are pedi- cels, and the small, more or less scale-like leaves of the peduncle are bracts.! Frequently the lower pedicels of a cluster on the general plan of the raceme are longer than the upper ones and make a some- what flat-topped cluster, like that of the hawthorn, ; the sheep laurel, or the trumpet creeper. This is called a corymb. In many cases, for ex- ample the parsnip, the Sweet Cicely, the gin- seng, and the cherry, a group of pedicels of nearly equal length A Fig. 131. — Catkins of Willow. A, staminate flowers ; B, pistillate flowers 1It is hardly necessary to say that the teacher will find it better in every way, if material is abundant, to begin the study of flower-clusters with the examination of typical specimens by the class, 188 FOUNDATIONS OF BOTANY spring from about the same point.. This produces a flower-cluster called the wmbel (Fig. 130). 199. Sessile Flowers and Flower-Clusters. — Often the pedicels are wanting, or the flowers are sessile, and then a modification of the raceme is produced which is called ; a spike, like that of the plantain (Fig. 132). The willow, alder, birch, poplar, and many other common trees bear a short, flexible, rather scaly spike (Fig. 181), which is called a catkin. The peduncle of a spike is often so much short- ened as to bring the flowers into a somewhat globu- lar mass. This is called a head (Fig. 1382). Around the base of the head usually occurs a circle of bracts known as the involucre. The same name is given to a set of bracts which often surround the bases of the pedicels in an umbel. 200. The Composite Head. — The plants of one large group, Fic. ie — Pilko at ies and of which the dandelion, the daisy, the thistle, and the sun- flower are well-known members, bear their flowers in close involucrate heads on a common receptacle. The whole cluster looks so much like a single flower that it is usually taken for one by non-botanical people. In many of the largest and most showy heads, like that of the sunflower and the daisy, there are two kinds of flowers, the ray-flowers, around the margin, and the tubular disk- flowers of the interior of the head (Fig. 133). The early botanists supposed the whole flower-cluster to be a single ARRANGEMENT OF FLOWERS ON THE STEM 189 Fic. 133.— Head of Yarrow. A, top view. (Magnified.) B, lengthwise section. (Magnified.) 7e, receptacle ; i, involucre; r, ray-flowers; d, disk-flowers; c, corolla; s, stigma; ch, chaff, or bracts of receptacle. Fia. 134. Fie. 135. — Compound Umbel Panicle of Oat. of Carrot. 190 FOUNDATIONS OF BOTANY compound flower. This belief gave rise to the name of one family of plants, Composite, that is, plants with com- pound flowers. In such heads as those of the thistle, the cud weed, and the everlasting there are no ray-flowers, and in others, like those of the dandelion and the chicory, all the flowers are ray-flowers. 201. Compound Flower-Clusters.——If the pedicels of a raceme branch, they may produce a compound raceme, or A B Cc D FIG. 136.— Diagrams of Inflorescence. A, panicle; B, raceme; C, spike; HZ, umbel; D, head. panicle, like that of the oat (Fig. 134).1 Other forms of compound racemes have received other names. An umbel may become compound by the branching. of its flower-stalks (Fig. 135), each of which then bears a little umbel, an wmbellet. 202. Inflorescence Diagrams. — The plan of inflorescence may readily be indicated by diagrams like those of Fig. 136. The student should construct such diagrams for some rather com- plicated flower-clusters, like those of the grape, horse-chestnut or buckeye, hardhack, vervain, or many grasses. 1 Panicles may also be formed by compound cymes (see Sect. 204). ARRANGEMENT OF FLOWERS ON THE STEM 191 203. Terminal Flowers; Determinate Inflorescence. — The terminal bud of a stem may be a flower-bud. In this case the direct growth of the stem is stopped or deter- mined by the appearance of the flower; hence such plants are said to have a determinate inflorescence. The simplest possible case of this kind is that in which the stem bears but one flower at its summit. 204. The Cyme. — Very often ‘flowers appear from lateral (axil- lary) buds, below the terminal flower, and thus give rise to a flower-cluster called a cyme. This may have only three flowers, and in that case would look very much like a three-flowered umbel. But in the raceme, corymb, and umbel the order of Fig. 137. — Compound Cyme of flowering is from below upward, Mouse-Ear Chickweed. or from the outside of the clus- —% *he terminal (oldest) flower. ter inward, because the lowest or the outermost flowers are the oldest, while in determinate forms of inflorescence the central flower is the oldest, and therefore the order of blossoming is from the center outwards. Cymes are very commonly compound, like those of the elder and of many plants of the pink family, such as the Sweet William and the. mouse-ear chickweed (Fig. 1387). They may also, as already mentioned, be panicled, thus making a cluster much like Fig. 136, A. CHAPTER XIV THE STUDY OF TYPICAL FLOWERS (Only one of the three flowers described to be studied by aid of these directions.) 205. The Flower of the Trillium. — Cut off the flower-stalk rather close to the flower; stand the latter, face down, on the table, and draw the parts then shown. Label the green leaf-like parts sepals, and the white parts, which alternate with these, petals. Turn the flower face up, and make another sketch, labeling the parts as before, together with the yellow enlarged extremities or anthers of the stalked organs called stamens. Note and describe the way in which the petals alternate with the sepals. Observe the arrangement of the edges of the petals toward the base, —how many with both edges outside the others, how many with both edges inside, how many with one edge in and one out. Note the veining of both sepals and petals, more distinct in which set?1 Pull off a sepal and make a sketch of it, natural size ; then remove a petal, flatten it out, and sketch it, natural size. Observe that the flower-stalk is enlarged slightly at the upper end into a rounded portion, the receptacle, on which all the parts of the flower rest. Note how the six stamens arise from the receptacle and their relations to the origins of the petals. Remove the remaining petals 1 In flowers with delicate white petals the distribution of the fibro-vascular bundles in these can usually be readily shown by standing the freshly cut end of the peduncle in red ink for a short time, until colored veins begin to appear in the petals. The experiment succeeds readily with apple, cherry, or plum blossoms; with white gilliflower the coloration is very prompt. Lily-of-the- valley is perhaps as interesting a flower as any on which to try the experi- ment, since the well-defined stained stripes are separated by portions quite free from stain, and the pistils are also colored. 192 THE STUDY OF TYPICAL FLOWERS 198 (cutting them off near the bottom with a knife), and sketch the sta- mens, together with the other object, the pistil, which stands in the center. Cut off one stamen, and sketch it as seen through the magnifying glass. Notice that it consists of a greenish stalk, the filament, and a broader portion, the anther (Fig. 149). The latter is easily seen to contain a prolongation of the green filament, nearly surrounded by a yellow substance. In the bud it will be found that the anther consists of two long pouches or anther-cells, which are attached by their whole length to the filament, and face inward (towards the center of the flower). When the flower is fairly open, the anther- cells have already split down their margins, and are discharging a yellow, somewhat sticky powder, the pollen. Examine one of the anthers with the microscope, using the two- inch objective, and sketch it. : Cut away all the stamens, and sketch the pistil. It consists of a stout lower portion, the ovary, which is six-ridged or angled, and which bears at its summit three slender stigmas. In another flower, which has begun to wither (and in which the ovary is larger than in a newly opened flower), cut the ovary across about the middle, and try to make out with the magnifying glass the number of chambers or cells which it contains. Examine the cross-section with the two-inch objective; sketch it, and note partic- ularly the appearance and mode of attachment of the undeveloped seeds or ovules with which it is filled. Make a vertical section of another rather mature ovary, and examine this in the same way. Using a fresh flower, construct a diagram to show the relation of the parts on an imaginary cross-section, as illustrated in Fig. 157.1 Construct a diagram of a longitudinal section of the flower, on the general plan of those in Fig. 155, but showing the contents of the ovary. Make a tabular list of the parts of the flower, beginning with the sepals, giving the order of parts and number in each set. 1 It is important to notice that such a diagram is not a picture of the section actually produced by cutting through the flower crosswise at any one level, but that it is rather a projection of the sections through the most typical part of each of the floral organs. 194 FOUNDATIONS OF BOTANY 206. The Flower of the Tulip.1— Make a diagram of a side view of the well-opened flower, as it appears when standing in sunlight. Observe that there is a set of outer flower-leaves and a set of inner ones.? Label the outer set sepals and the inner set petals. In most flowers the parts of the outer set are greenish, and those of the inner set of some other color. It is often convenient to use the name perianth, meaning around the flower, for the two sets taken together. Note the white waxy bloom on the outer surface of the outer seg- ments of the perianth. What is the use of this? Note the manner in which the inner segments of the perianth arise from the top of the peduncle and their relation to the points of attachment of the outer segments. In a flower not too-widely opened, note the relative posi- tion of the inner segments of the perianth, how many wholly outside the other two, how many wholly inside, how many with one edge in and one edge out. Remove one of the sepals by cutting it off close to its attachment to the peduncle, and examine the veining by holding it up in a strong light and looking through it. Make a sketch to show the general outline and the shape of the tip. Examine a petal in the same way, and sketch it. Cut off the remaining portions of the perianth, leaving about a quarter of an inch at the base of each segment. Sketch the upright, triangular, pillar-like object in the center, label it pistil, sketch the organs which spriug from around its base, and label these stamens. Note the fact that each stamen arises froma point just above and within the base.of a segment of the perianth. Each stamen consists of a somewhat conical or awl-shaped portion below, the filament, sur- mounted by an ovate linear portion, the anther. Sketch one of the stamens about twice natural size and label it x 2. Is the attach- ment of the anther to the filament such as to admit of any nodding or twisting movement of the former? In a young flower, note the two tubular pouches or anther-cells of which the anther is composed, and the slits by which these open. Observe the dark-colored pollen 1 Tulipa Gesneriana. As the flowers are rather expensive, and their parts are large and firm, it is not absolutely necessary to give a flower to each pupil, but some may be kept entire for sketching and others dissected by the class. All the flowers must be single. 2 Best seen in a flower which is just opening. THE STUDY OF TYPICAL FLOWERS 195 which escapes from the anther-cells and adheres to paper or to the fingers, Examine a newly opened anther with the microscope, using the two-inch objective, and sketch it. Cut away all the stamens and note the two portions of the pistil, a triangular prism, the ovary, and three roughened scroll-like objects at the top, the three lobes of the stigma. Make a sketch of these parts about twice natural size, and label them x 2. ‘ouch a small camel's-hair pencil to one of the anthers, and then transfer the pollen thus removed to the stigma. This operation is merely an imitation of the work done by insects which visit the flowers out of doors. Does the pollen cling readily to the rough stigmatic surface? Examine this adhering pollen with the two-inch objective, and sketch a few grains of it, together with the bit of the stigma to which it clings. Compare this drawing with Fig. 162. Make a cross-section of the ovary about midway of its length, and sketch the section as seen through the magnifying glass. Label the three chambers shown cells of the ovary ' or locules, and the white egg-shaped objects within ovules.? Make a longitudinal section of another ovary, taking pains to secure a good view of the ovules, and sketch as seen through the magnifying glass. Making use of the information already gained and the cross- section of the ovary as sketched, construct a diagram of a cross- section of the entire flower on the same general plan as those shown in Fig. 157.8 Split a flower lengthwise,4 and construct a longitudinal section of the entire flower on the plan of those shown in Fig. 155, but showing the contents of the ovary. 207. The Flower of the Buttercup.— Make a diagram of the mature flower as seen in a side view, looking a little down into it. Label the pale greenish-yellow, hairy, outermost parts sepals, and 1 Notice that the word cell here means a comparatively large cavity, and is not used in the same sense in which we speak of a wood-cell or a pith-cell. 2 The section will be more satisfactory if made from an older flower, grown out of doors, from which the perianth has fallen: In this case label the con- tained objects seeds. 8 Consult also the footnote on p. 193. 4 One will do for an entire division of the class. 196 FOUNDATIONS OF BOTANY the larger bright yellow parts above and within these petals, and the yellow-knobbed parts which occupy a good deal of the interior of the flower stamens. Note the difference in the position of the sepals of a newly opened flower and that of the sepals of a flower which has opened as widely as possible. Note the way in which the petals are arranged in relation to the sepals. In an opening flower observe the arrange- ment of the edges of the petals, how many entirely outside the others, how many entirely inside, how many with one edge in and the other out. Cut off a sepal and a petal, each close to its attachment to the flower ; place both, face down, on a sheet of paper, and sketch about twice the natural size and label it x 2. Describe the difference in appearance between the outer and the inner surface of the sepal and of the petal. Note the little scale at the base of the petal, inside. Strip off all the parts from a flower which has lost its petals, until nothing is left but a slender conical object a little more than an eighth of an inch in length. This is the receptacle or summit of the peduncle. In a fully opened flower, note the numerous yellow-tipped stamens, each consisting of a short stalk, the filament, and an enlarged yellow knob at the end, the anther. Note the division of the anther into two portions, which appear from the outside as parallel ridges, but which are really closed tubes, the anther-cells. Observe in the interior of the flower the somewhat globular mass (in a young flower almost covered by the stamens). This is a group of pistils. Study one of these groups in a flower from which the stamens have mostly fallen off, and make an enlarged sketch of the head of pistils. Remove some of the pistils from a mature head, and sketch a single one as seen with the magnifying glass. Label the little knob or beak at the upper end of the pistil stigma, and the main body of the pistil the ovary. Make a section of one of the pistils, parallel to the flattened surfaces, like that shown in Fig. 150, and note the partially matured seed within. CHAPTER XV PLAN AND STRUCTURE OF THE FLOWER AND ITS ORGANS 208. Parts or Organs of the Flower. — Most showy flowers consist, like those studied in the preceding chap- ter, of four circles or sets of organs, the sepals, petals, stamens, and pistils. The sepals, taken together, consti- tute the calyx; the petals, taken together, constitute the corolla (Fig. 188).1 Some- Z times it is convenient to have a word to comprise both calyx and corolla; for this the term perianth is used. A flower which contains all four of these sets is said to be com- plete. Since the work of the flower is to produce seed, and " seed-forming is due to the Fic. 138.— The Parts of the Flower. codperation of stamens and cal, calyx; cor, corolla; st, pistils, or, as they are often eee called from their relation to the reproductive organs of spore-plants, microsporophylls and macrosporophylls (see Sect. 374), these are known as the essential organs (Fig. 188). The simplest possible pistil is a dwarfed and 1 The flower of the waterleaf Hydrophyllum canadense, modified by the omission of the hairs on the stamens, is here given because it shows so plainly the relation of the parts. 197 198 FOUNDATIONS OF BOTANY greatly modified leaf (Sect. 222), adapted into a seed- bearing organ. Such a pistil may be one-seeded, as in Fig. 166, or several-seeded, as in the diagrammatic one (Fig. 150); itis called a carpel. The calyx and corolla are also known as the floral envelopes. Flowers which have the essential organs are called perfect flowers. They may, therefore, be perfect without being complete. Incomplete flowers with only one row of parts in the perianth are said to be apetalous (Fig. 139). 209. Regular.and Symmetrical Flowers. —A flower is regular if all the parts of the same set or circle are alike in size and shape, as in the stonecrop (Fig. 140). Such a€ flowers as that of the violet, the monkshood, Fic. 139.— Apetal- and the sweet pea (Fig. 141) are irregular. ous Flower of cm (European) wild Symmetrical flowers are those whose calyx, senees corolla, circle of stamens, and set of carpels consist each of the same number of parts, or in which the number in every case is a multiple of the smallest number found in any set. The stonecrop is Fic. 140.— Flower of Stonecrop. I, entire flower (magnified) ; II, vertical section (magnified). symmetrical, since it has five sepals, five petals, ten sta- mens, and five carpels. Roses, mallows, and mignonette * STRUCTURE OF THE FLOWER AND ITS ORGANS 199 are familiar examples of flowers which are unsymmet- rical because they have a large, indefinite number of stamens ; the portulaca is unsymmetrical, since it has two divisions of the calyx, five or six petals, and seven to twenty stamens. 210, The Receptacle.— The parts of the flower are borne on an expansion of the peduncle, called the recep- tacle. Usually, as in the flower of the grape (Fig. 250), this is only a slight enlargement of the peduncle, but in Fig. 141. — Irregular Corolla of ki Sweet Pea. } A, side view ; B, front view ; s, stand- A ard; ww, wings; &, keel. the lotus and the magnolia the receptacle is of great size, particularly after the petals have fallen and the seed has ripened. The receptacle of the rose (Fig. 142) is hollow, and the pistils arise from its interior surface. 211. Imperfect or Separated Flowers. — The stamens and pistils may be produced in separate flowers, which are, of course, imperfect. This term does not imply that such flowers do their work any less perfectly than others, but only that they have not both kinds of essential organs. In the very simple imperfect flowers of the willow (Fig. 148) each flower of the catkin (Fig. 131) consists merely 200 FOUNDATIONS OF BOTANY of a pistil or a group of (usually two) stamens, springing from the axil of a small bract. Staminate and pistillate flowers may be borne on differ- ent plants, as they are in the willow, or they may be borne on the same plant, as in the hickory and the hazel, among trees, or in the castor-oil plant, Indian corn, and the begonias. When staminate and pistillate flowers are borne on separate plants, such a plant is said to be diccious, that is, of two households; when both kinds of flower appear on the same individual, the plant is said to be monecious, that is, of one household. 212. Study of Imperfect Flowers. — Examine, draw, and describe the imperfect flowers of some‘of the following dicecious plants and one of the moncecious plants :1 early meadow rue. Diccious plants. . . . .... willow. poplar. ( walnut, oak, chestnut. Moneecious plants . ... . ‘ hickory, alder, beech. birch, hazel, begonia. 213. Union of Similar Parts of the Perianth. — The sepals may appear to join or cohere to form a calyx which is more or less entirely united into one piece, as in Figs. 139 and 148. In this case the calyx is said to be gamo- sepalous, that is, of wedded sepals. In the same way the corolla is frequently gamopetalous, as in Figs. 144-148. Frequently the border or limb of the calyx or corolla is more or less cut or lobed. In this case the projecting 1¥For figures or descriptions of these or allied flowers consult Gray’s Manual of Botany, Emerson’s Trees and Shrubs of Massachusetts, Newhall’s Trees of the Northern United States, or Le Maout and Decaisne’s Traité Général de Botanique. STRUCTURE OF THE FLOWER AND ITS ORGANS 201 portions of the limb are known as divisions, teeth, or ‘lobes.’ Special names of great use in accurately describing plants are given to a large number of forms of the gamo- Fic, 142, A Rose, Longitudi- nal Section. petalous corolla. Only a few of these names are here given, in connection with the figures. When the parts of either circle of the perianth are wholly unconnected with each other, that is, polysepalous or polypetalous, such parts are said to be distinct. 214, Parts of the Stamen and the Pistil. — The stamen usually consists of a hollow portion, the anther (Fig. 149, a), borne on a stalk called the filament (Fig. 149, f), which is often lacking. Inside the anther is a pow- dery or pasty substance called pollen or microspores (Sect. 374). The pistil usually consists of a small chamber, the ovary, which contains the ovules, macrospores (Sect. 374), or rudimentary seeds, a slen- der portion or stalk, called the style, and at the top of this a ridge, knob, or point called the stigma. These parts are all shown in Fig. 150. In many pistils the stigma is borne directly on the ovary. 215. Union of Stamens with Each Other.— Stamens may Fie, 143.— Flowers of Willow. (Magnified.) be wholly unconnected with A, staminate flower ; B, pistillate flower. 1 It would not be safe to assume that the gamosepalous calyx or the gamo- petalous corolla is really formed by the union of separate portions, but it is very convenient to speak of it as if it were. 202 FOUNDATIONS OF BOTANY each other or distinet, or they may cohere by their fila- ments into a single group, when they are said to be monadelphous, of one brotherhood (Fig. 151), into two groups (diadelphous) (Fig. 152), or into many groups. In some flowers the stamens are held together in a ring by their coherent anthers (Fig. 153). 2 216. Union of Pistils.— The pistils may be entirely separate from each other, distinct and simple, as they are Fic. 144.—Bell-Shaped , Corollaof Bell-Flower in the buttercup and the stonecrop, or a ga several may join to form one compound pistil of more or less united carpels. In the latter case the union generally affects the ovaries, but often leaves the styles separate, or it may result in joining ovaries and styles, but leave the stigmas separate or at any rate lobed, so as to show of how many separate carpels the compound pistil is made up. Even when there is no external sign to show the compound nature of the pistil, it can usu- ally be recognized from the study of a cross-section of the Fie. 145, — Salver-Shaped Fie. 146. Corolla of Jasmine. Ovary. ‘Wheel-Shaped Corolla (Magnified.) 217. Cells of the of Potato. Ovary; Placentas.— Compound ovaries are very com- monly several-celled, that is, they consist of » number of STRUCTURE OF THE FLOWER AND ITS ORGANS 203 separate cells’ or chambers, more scientifically known as locwles, Fig. 154, B, shows a three-celled ovary seen in eross-section. The ovules are not borne indis- criminately by any part of the lining of the ovary. .In one-celled. pistils they frequently grow in a line running along one side of the ovary, as in the pea pod (Fig. 271). The ovule-bearing line is called a placenta ; in compound g Fig; 149.—Partsof a F16. 150.— Parts Fie. 147.—Tubu- Fie. 148, —Labi- Stamen, pine Eset: lar Corolla, from ate or Ringent 4, front; B,back;a,an- ov, ovary. Head of Bache- Corolla of Dead ther; c, connective; sty, style. lor’s Button. Nettle. J, filament. stig, stigma. separate pistils joined to make the compound one. Pla- centas on the wall of the ovary, like those in Fig. 154, A, are called parietal placentas ; those which occur as at B, in the same figure, are said to be central, and those which, like the form represented in C of the same figure, consist of a column rising from the bottom of the ovary are called free central placentas. 1 Notice that the word cell is here used in an entirely different sense from that in which it has been employed in the earlier chapters of this book. As applied to the ovary, it means a chamber or compartment. 204 FOUNDATIONS OF BOTANY 218. Union of Separate Circles. —'The members of one of the circles of floral organs may join those of another circle, thus becoming adnate, adherent, or consolidated. Fig, 151. Monadelphous In Fig. 189 the calyx tube is adnate to the ovary. In this case the parts of the flower do not all appear to spring from the receptacle. Fig. 155 illustrates three common cases as regards insertion of the parts of the flower. In I they are,all inserted on the receptacle, and the corolla and stamens are said to be hypogynous, that is, beneath the pistil.". In II the petals and the stamens appear as if they Stamensof had grown fast to the calyx for some distance, Mallow. therefore said to be perigynous, that is, around the pistil. In III all the parts are free or unconsolidated, except the petals and stamens; the stamens may be described as epipetalous, that is, growing on the petals. Sometimes some or all “3 of the other parts stand upon the ovary, and such Fic. 152, —Diadelphous parts are said to be epig- Stamens of Sweet Pea. ynous, that is, on the ovary, like the petals and stamens of the white water-lily (Fig. 156). 219. Floral Diagrams. — Sections (real or imaginary) through the flower length- wise, like those of Fig. 155, help greatly so that they surround the pistil, and they are Fig. 153, —Stamens of a Thistle, with Anthers united into a Ring. in giving an accurate idea of the relative % united anthers; /, position of the floral organs. Still more filaments, bearded on the sides. STRUCTURE OF THE FLOWER AND ITS ORGANS 205 important in this way are cross-sections, which may be recorded in diagrams like those of Fig. 157.1. In con- structing such diagrams it es oS will often be necessary to suppose some of the parts &) SY Cs of the flower to be raised a B Cc or lowered from their true Fic. 154. — Principal Types of Placenta. position, so as to bring A, parietal placenta; B, central placenta ; . . C, free central placenta; Aand B, trans- them into such relations verse sections ; C, longitudinal section. that all could be cut by a single section. This would, for instance, be necessary in making a diagram for the cross-section of the flower y II y RAK j : SS Fig. 155.— Insertion of the Floral Organs. I, Hypogynous, al) the other parts on the receptacle, beneath the pistil ; I, Perigynous, petals and stamens apparently growing out of the calyx, FIG. 156.— White Water-Lily. The around the pistil; III, corolla inner petals and the stamens grow- hypogynous, stamens epipetalous. ing from the ovary. of the white water-lily, of which a partial view of one side is shown in Fig. 156.7 1¥For floral diagrams see Le Maout and Decaisne’s Traité Général de Botanique, or Hichler’s Blithendiagramme. 2 It is best to begin practice on floral diagrams with flowers so firm and large that actual sections of them may be cut with ease and the relations of the parts in the section readily made out. The tulip is admirably adapted for this purpose. 206 FOUNDATIONS OF BOTANY Construct diagrams of the longitudinal section and the transverse section of several large flowers, following the method indicated in Figs. 155 and 157, but making the longitudinal section show KES the interior of the ovary. It (pea \\\ is found convenient to distin- ie ry We SF Til I I Fic. 157. — Diagram of Cross-Sections of Flowers. I, columbine ; II, heath family ; IL, iris family. In each diagram the dot along- side the main portion indicates a cross-section of the stem of the plant. In II every other stamen is more lightly shaded, because gome plants of the heath family have five and some ten stamens. guish the sepals from the petals by representing the former with midribs. The diagrammatic symbol for a stamen stands for a cross-section of the anther, and that for the pistil is a section of the ovary. If any part is lacking in the flower (as in the case of flowers which have some antherless filaments) the missing or abortive organ may be indicated by a dot. In the diagram of the Tris Family (Fig. 157, ITI) the three dots inside the flower indicate the position of a second circle of stamens, found “in most flowers of monocotyledons but not found in this family. 1 Among the many excellent early flowers for this purpose may be men- tioned trillium, bloodroot, dogtooth violet, marsh marigold, buttercup, tulip tree, horse-chestnut, Jeffersonia, May-apple, cherry, apple, crocus, tulip, daffodil, primrose, wild ginger, cranesbill, locust, bluebell. STRUCTURE OF THE FLOWER AND ITS ORGANS 207 220. Review Summary of Chapter XV.! 1. Kinds of flowers as regards number of circles or 2. sets of organs present 3. 4, Kinds as regards numerical plan 5 Kinds as regards similarity of parts of the same { 1. circle . ae eee ee 2. eT Parts of astamen . . lg By Ss: Bh eae 9 1. , Parts of apistil . . . ae dee aa ie 2. 3. Stamens as regards union with each other Pistils as regards union with each other . Degree of union of separate circles poe Gees ey NO Ee ee 1 Illustrate by sketches. CHAPTER XVI TRUE NATURE OF FLORAL ORGANS; DETAILS OF THEIR STRUCTURE; FERTILIZATION 221. The Flower a Shortened and greatly Modified Branch. — In Chapter VIII, the leaf-bud was explained as being an undeveloped branch, which in its growth would develop into a real branch (or a prolongation of the main stem). Now, since flower-buds appear regularly Fia@, 158. — Transition from Bracts to Sepals in a Cactus Flower. ’ either in the axils of leaves or as terminal buds, there is reason to regard them as of similar nature to leaf-buds. This would imply that the receptacle corresponds to the axis of the bud shown in Fig. 86, and that the parts of the flower correspond to leaves. There is plenty of evi- dence that this is really true. Sepals frequently look very much like leaves, and in many cacti the bracts 208 TRUE NATURE OF FLORAL ORGANS 209 about the flower are so sepal-like that it is impossible to tell where the bracts end and the sepals begin (Fig. 158). The same thing is true of sepals and petals in such flowers as the white water-lily. In this flower there is a remark- able series of intermediate steps, ranging all the way from petals, tipped with a bit of anther, through stamens with a broad petal-like filament, to regular stamens, as is shown in Fig. 159, #, F, G, H. The same thing is shown in Fig. 159. — Transitions from Petals to Stamens in White Water-Lily. E, F, G, H, various steps between petal and stamen. many double roses. In completely double flowers all the essential organs are transformed by cultivation into petals. In the flowers of the cultivated double cherry the pistils occasionally take the form of small leaves, and some roses turn wholly into green leaves. Summing up, then, we know that flowers are altered and shortened branches: (1) because flower-buds have as regards position, the same kind of origin as leaf-buds; (2) because all the intermediate steps are found between bracts, on the one hand, and stamens, on the other ; (3) 210 FOUNDATIONS OF BOTANY because the essential organs are found to be replaced by petals or even by green leaves. The fact that leaves should be so greatly modified as they are in flowers and given work to do wholly different from that of the other kinds of leaves so far studied need not strike one as exceptional. In many of the most highly developed plants below the seed-plants, organs correspond- ing to flowers are found, and these consist of modified leaves, set apart for the work of reproducing (Sect. 367). 222. Mode of Formation of Stamens and Pistils from Leaves. — It is hardly possible to state, until after Chap- ter XXIII has been studied, how stamens stand related to leaves.} The simple pistil or carpel is supposed to be made on the plan of a leaf folded along the midrib until its margins touch, like the cherry leaf in Fig. 87. But the student must not understand by this statement that the little pistil leaf grows at first like an ordinary leaf and finally becomes folded in. The united leaf-margins near the tip would form the stigma, and the placenta would correspond to the same margins, rolled slightly inwards, extending along the inside of the inflated leaf-pouch. Place several such folded leaves upright about a common center, and their cross-section would be much like that of B in Fig. 154. Evidence that carpels are really formed in this way may be gained from the study of such fruits as that of the monkshood (Fig. 168), in which the ripe carpels may be seen to unfold into a shape much more leaf-like than that which they had while the pistil was maturing. What “4 “The anther answers exactly to the spore-cases of the ferns and their allies, while the filament is a small specialized leaf to support it.” For a fuller statement, see Potter and Warming’s Systematic Botany; pp. 236, 237. TRUE NATURE OF FLORAL ORGANS 211 really occurs is this: the flower-bud, as soon as it has developed far enough to show the first rudiments of the essential organs, contains them in the form of minute knobs. These are developed from the tissues of the plant in the same manner as are the knobs in a leaf-bud, which afterwards become leaves (Fig. 87, II); but as growth and development progress in the flower-bud, its con- tents soon show themselves to be stamens and pistils (if the flower is a perfect one). 223. The Anther and its Contents.—Some of the shapes of the anthers may be learned from Figs. 149 and 160.1 The shape of the F14- 160.—Modes of discharging Pollen. anther and the way in which at; Cia felted aves thee it opens depend largely upon _ berry); III, by apore at the top of each ie way ata abel thie pollen anther-lobe (nightshade). is to be discharged and how it is carried from flower tc flower. The commonest method is to have the anther- cells split lengthwise, as in Fig. 160, I. A few anthers open by trap-doors like valves, as in II, and a larger number by little holes at the top, as in. III. The pollen in many plants with inconspicuous flowers, as the evergreen cone-bearing trees, the grasses, rushes, and. sedges, is a fine, dry powder. In plants with showy flowers it is often somewhat sticky or pasty. . The forms of pollen grains are extremely various. Fig. 161 will serve to furnish examples of some of the shapes which 1 See Kerner and Oliver’s Natural History of Plants, Vol. II, pp. 86-95. 212 FOUNDATIONS OF BOTANY the grains assume; ¢ in the latter figure is perhaps as common a form asany. Each pollen grain consists mainly of a single cell, and is covered by a moderately thick outer wall and a thin inner one. Its contents are thickish protoplasm, full of little opaque particles and usually containing grains of starch and little drops of oil. The knobs on the outer coat, as shown in Fig. 161 6, mark b C d e Fic. 161. — Pollen Grains. (Very greatly magnified.) a, pumpkin ; 6, enchanter’s nightshade ; c, Albuca; d, pink ; e, hibiscus. the spots at which the inner coat of the grain is finally to burst through the ovfter one, pushing its way out in the form of a slender, thin-walled tube.} 224, The Formation of Pollen Tubes. — This can be studied in pollen grains which have lodged on the stigma and there been subjected to the action of its moist surface. It is, however, easier to cause the artificial production of the tubes. x EXPERIMENT XXXVIII Production of Pollen Tubes. — Place a few drops of suitably diluted syrup with some fresh pollen in a concave cell ground in a micro- scope slide; cover with thin glass circle; place under a bell-glass, with a wet cloth or sponge, to prevent evaporation of the syrup, and set aside in a warm place, or merely put some pollen in syrup in a 1 See Kerner and Oliver’s Natural History of Plants, Vol. 1, pp. 95-104. FERTILIZATION 2138 watch crystal under the bell-glass. Examine from time to time to note the appearance of the pollen tubes. Try several kinds of pollen if possible, using syrups of various strengths. The follow- ing kinds of pollen form tubes readily in syrups of the strengths indicated. Tulip ‘ : : ‘ 1 to 3 per cent. Narcissus. , : 3 ; 8to5 « Cytisus canariensis (called Genista by florists) 15 « Chinese primrose ‘ : 5 i 10 Sweet pea} ; . 10to15 « Tropzolum 4 : , 15 « 225. Microscopical Structure of the Stigma and Style. Under a moderate power of the microscope the stigma is seen to consist of cells set irregularly over the surface, and secreting a moist liquid to which the pollen grains adhere (Fig. 162). Beneath these superficial cells and running down through the style (if there is one) to the ovary is spongy parenchyma. In some pistils the pollen tube proceeds through the cell walls, which it softens by means of a substance which it exudes for that purpose. In other cases (Fig. 163) there is a canal or passage, Fia. 162. — Stigma of Thorn- along which the pollen tube travels Apple (Datura) with Pollen. ' ified. on its way to the ovule. NE 1 The sweet-pea pollen and that of Tropzolum are easier to manage than any other kinds of which the author has personal knowledge. If a concaved slide is not available, the cover-glass may be propped up on bits of the thin- nest broken cover-glasses. From presence of air or some other reason, the formation of pollen tubes often proceeds most rapidly just inside the margin of the cover-glass. 214 FOUNDATIONS OF BOTANY 226. Fertilization. — By fertilization in seed-plants the botanist means the union of a generative cell from a pol- Fic. 163, — Pollen Grains producing Tubes, on Stigma of a Lily. (Much magnified.) g, pollen grains ; #, pollen tubes; p, papille of stigma; c, canal or pas- sage running toward ovary. Fic. 164.— Pollen Grain of Snow- flake (Leucoiwm) producing a Pol- len Tube with Two Naked Genera- tive Cells. len grain with that of an egg-cell at the apex of the embryo sac (Fig. 165). This process gives rise to a cell which contains material derived from the pollen and from the egg-cell. In a great many plants the pollen, in order to accomplish the most successful fertilization, must come from another plant of the same kind, not from the indi- vidual which bears the ovules that are being fertilized. Pollen tubes begin to form soon after pollen grains lodge on the stigma. The time re- quired for the process to begin varies in different kinds of plants, requiring in many cases twenty-four hours or more. The length of time needed for the pollen tube to make its way through the style to the ovary depends upon the length of the style and other conditions. In the crocus, which has a style several inches long, the descent takes from one to three days. Finally the tube penetrates the opening at the apex of FERTILIZATION 215 the ovule m, in Fig. 165, reaches one of the cells shown at e, and transfers a generative cell into this egg-cell. The latter is thus enabled to divide and grow rapidly into an embryo. This the cell does by forming cell-walls and then in- creasing by continued subdivision, in much the same way in which the cells at the growing point near the tip of the root, or those of the cambium layer, subdivide.! 227. Nature of the Fertilizing Process. — The necessary feature of the process of fertiliza- tion is the union of the essential contents of two cells to form a new one, from which the future plant is to spring. This kind of union is found to occur in many cryp- togams (Chapters XX-XXII), resulting in the production of a spore capable of grow- Fig. 165. - Diagrammatic Representation of Fertilization of an Ovule. i, inner coating of ovule; 0, outer coating of ovule; p, pollen tube, proceeding from one of the pollen grains on the stigma; ec, the place where the two coats of the ovule blend. (The kind of ovule here shown is inverted, its opening m being at the bottom, and the stalk f adhering along one side of the ovule.) a toe, embryo sac, full of pro- toplasm ; a, so-called antipodal cells of em- bryo sac; 7, central nucleus of the embryo sac; e, nucleated cells, one of which, the egg-cell, receives the essential contents of the pollen tube; f, funiculus or stalk of ovule; m, opening into the ovule. ing into a complete plant like that which produced it. 1 See Kerner and Oliver’s Natural History of Plants, Vol. I, pp. 401-420. 216 FOUNDATIONS OF BOTANY 228. Number of Pollen Grains to Each Ovule. — Only one pollen tube is necessary to fertilize each ovule, but so many pollen grains are lost that plants produce many more of them than of ovules. The ratio, however, varies greatly. In the night-blooming cereus there are about 250,000 pollen grains for 30,000 ovules, or rather more than 8 to 1, while in the common garden wistaria there are about 7000 pollen grains to every ovule, and in Indian corn, the cone-bearing evergreens, and a multitude of other plants, many times more than 7000 to 1. These differences depend upon the mode in which the pollen is carried from the stamens to the pistil. CHAPTER XVII THE STUDY OF TYPICAL FRUITS 229. A Berry, the Tomato.!— Study the external fotm of the tomato, and make a sketch of it showing the persistent calyx and peduncle. Cut a cross-section at about the middle of the tomato. Note the thickness of the epidermis (peel off a strip) and of the wall of the ovary. Note the number, size, form, and contents of the cells of the ovary. Observe the thickness and texture of the partitions between the cells. Sketch. : Note the attachments of the seeds to the placentas and the gelati- nous, slippery coating of each seed. The tomato is a typical berry, but its structure presents fewer points of interest than are found in some other fruits of the same general character, so the student will do well to spend a little more time on the examination of such fruits as the orange or the lemon. 230. A Hesperidium, the Lemon. — Procure a large lemon which is not withered, if possible one which still shows the remains of the calyx at the base of the fruit. Note the color, general shape, surface, remains of the calyx, knob at portion formerly occupied by the stigma. Sketch the fruit about natural size. Examine the pitted surface of the rind with the magnifying glass and sketch it. Remove the bit of stem and dried-up calyx from the base of the fruit; observe, above the calyx, the knob or disk on which the pistil stood. Note with the magni- fying glass and count the minute whitish raised knobs at the bottom of the saucer-shaped depression left by the removal of the disk. What are they ? 1 Fresh tomatoes, not too ripe, are to be used, or those which have been kept over from the previous summer in formalin solution. The very smallest varieties, such as are often sold for preserving, are as good for study as the larger kinds. 217 218 FOUNDATIONS OF BOTANY Make a transverse section of the lemon, not more than a fifth of the way down from the stigma end and note: (1) The thick skin, pale yellow near the outside, white within. (2) The more or less wedge-shaped divisions containing the juicy pulp of the fruit. These are the matured cells of the ovary; count these. (3) The thin partition between the cells. (4) The central column or axis of white pithy tissue. (5) The location and attachment of any seeds that may be encountered in the section. Make a sketch to illustrate these points, comparing it with Fig. 171. Study the section with the magnifying glass and note the little spherical reservoirs near the outer part of the skin, which contain the oil of lemon which gives to lemon peel its characteristic smell and taste. Cut-with the razor a thin slice from the surface of a lemon peel, some distance below the section, and at once examine the freshly cut surface with a magnifying glass to see the reservoirs, still containing oil, which, however, soon evaporates. On the cut surface of the pulp (in the original cross-section) note the tubes in which the juice is contained. These tubes are not cells, but their walls are built of cells. Cut a fresh section across the lemon, about midway of its length and sketch it, bringing out the same points which were shown in the previous one. The fact that the number of ovary cells in the fruit corresponds with the number of minute knobs in the depression at its base is due to the fact that these knobs mark the points at which fibro-vascular bundles passed from the peduncle into the cells of the fruit, carrying the sap by which the growth of the latter was maintained. Note the toughness and thickness of the seed-coats. Taste the kernel of the seed. Cut a very thin slice from the surface of the skin, mount in water, and examine with a medium power of the microscope. Sketch the cellular structure shown and compare it with the sketch of the corky layer of the bark of the potato tuber. Of what use to the fruit is a corky layer in the skin? (See Sect. 453 for further questions.) THE STUDY OF TYPICAL FRUITS 219 231. A Legume, the Bean-Pod.1— Lay the pod flat on the table and make a sketch of it, about natural size. Label stigma, style, ovary, calyx, peduncle. Make a longitudinal section of the pod, at right angles to the plane in which it lay as first sketched, and make a sketch of the section, showing the partially developed seeds, the cavities in which they lie, and the solid portion of the pod between each bean and the next. Split another pod, so as to leave all the beans lying undisturbed on one-half of it and sketch that half, showing the beans lying in their natural position and the funiculus or stalk by which each is attached to the placenta; compare Fig. 271. Make a cross-section of another pod, through one of the beans, sketch the section, and label the placenta (formed by the united edges of the pistil leaf) and the midrib of the pistil leaf. Break off sections of the pod and determine, by observing where the most stringy portions are found, where the fibro-vascular bundles are most numerous. Examine some ripe pods of the preceding year,? and notice where the dehiscence, or splitting open of the pods, occurs, whether down the placental edge, ventral suture, the other edge, dorsal suture, or both. 232. An Akene, the Fruit of Dock.— Hold in the forceps a ripe fruit of any of the common kinds of dock,® and examine with the magnifying glass. Note the three dry, veiny, membranaceous sepals by which the fruit is enclosed. On the outside of one or more of the sepals is found a tubercle or thickened appendage which looks like a little seed or grain. Cut off the tubercles from several of the fruits, put these, with some uninjured ones, to float in a pan of water, and watch their behavior for several hours. What is appar- ently the use of the tubercle? 1 Any species of bean (Phaseolus) will answer for this study. Specimens in the condition known at the markets as “shell-beans ’’ would be best, but these are not obtainable in spring. Ordinary “‘string-beans ”’ will do. 2 Which may be passed round for that purpose. They should have been saved and dried the preceding autumn. 3 Rumex crispus, R. obtusifolius, or R. verticillatus. This should have been gathered and dried the preceding summer. 220 FOUNDATIONS OF BOTANY Of what use are the sepals, after drying up? Why do the fruits cling to the plant long after ripening? Carefully remove the sepals and examine the fruit within them. What is its color, size, and shape? Make a sketch of it as seen with the magnifying glass. Note the three tufted stigmas, attached by slender threads to the apex of the fruit. What does their tufted shape indicate? What evidence is there that this seed-like fruit is not really a seed? Make a cross-section of a fruit and notice whether the wall of the ovary can be seen, distinct from the seed-coats. Compare the dock fruit in this respect with the fruit of the buttercup, shown in Fig. 166. Such a fruit as either of these is called an akene. CHAPTER XVIII THE FRUIT! 233. What constitutes a Fruit. — It is not easy to make a short and simple definition of what botanists mean by the term fruit. It has very little to do with the popular use of the word. Briefly stated, the definition may be given as follows: The fruit consists of the matured ovary and contents, together with any intimately connected parts. Botanically speaking, the bur of beggar’s ticks (Fig. 278), the three-cornered grain of buckwheat, or such true grains as wheat and oats, are as much fruits as is an apple or a peach. The style or stigma sometimes remains as an important part of the fruit in the shape of a hook, as in the common hooked crowfoot; or in the shape of a plumed appendage, as in the virgin’s bower, often called wild hops. The calyx may develop hooks, as in the agrimony, or plumes, as in the thistle, the dandelion, lettuce, and many other familiar plants. In the apple, pear, and very many ber- ries, the calyx becomes enlarged and pulpy, often consti- tuting the main bulk of the mature fruit. The receptacle not infrequently, as in the apple, forms a more or less important part of the fruit. 234. Indehiscent and Dehiscent Fruits. — All of the fruits considered in the next three sections are indehiscent, 1See Gray’s Structural Botany, Chapter VII, also Kerner and Oliver’s Natural History of Plants, Vol. Il, pp. 427-438. 221 222 FOUNDATIONS OF BOTANY that is, they remain closed after ripening. Dehiscent fruits when ripe open in order to discharge their seeds. The three classes which im- mediately follow Sect. 237 belong to this division. 235. The Akene. — The one-celled and one-seeded pistils of the buttercup, ‘strawberry, and many other flowers, ripen into a little Fic. 166.— Akenes of a Buttercup. fruit called an. akene (Fig. A, head of akenes ; B, section of a single 166). Such fruits, from ST their small size, their dry consistency, and the fact that they never open, are usually taken for seeds by those who are not botanists. In the group of plants to which the daisy, the sunflower, and the dandelion belong, the akenes consist of the ovary and the adherent calyx tube. The limb of the calyx is borne on the summit of many akenes, sometimes in the form of teeth, sometimes as a tuft of hairs or bristles (Fig. 267). 236. The Grain. — Grains, such as corn, wheat, oats, bar- ley, rice, and so on, have the ‘interior of the ovary com- pletely filled by the seed, and the seed-coats and the wall of the ovary are firmly united, as shown in Fig. 6. 237. The Nut.— A nut (Fig. 167) is larger than an akene, usually has a harder shell, and commonly contains Fic. 167, — Chestnuts. THE FRUIT 223 a seed which springs from a single ovule of one cell of a compound ovary, which develops at the expense of all the other ovules. The chestnut-bur is a kind of involucre, and so is the acorn-cup. The name nut is often incorrectly applied in popular language; for example, the we, so-called Brazil-nut is really a large seed with a very hard testa. 238. The Follicle. — One-celled, 4 simple pistils, like those of the marsh Z marigold, the columbine, and a good | ~ many other plants, often produce a Fig. 168.—Group of Foui- fruit which dehisces along a single oe and 2 Single Follicle suture, usually the ventral one. Such a fruit is called a follicle (Fig. 168). 239. The Legume.— A legume is a one-celled pod, formed by the maturing of a simple pistil, which dehisces along both of its sutures, as already seen in the case of the bean pod, and illus- trated in Fig. 271. 240. The Capsule: — The dehiscent fruit formed by the ripening of a compound pistil is called a capsule. Such a fruit may. be one- celled, as in the linear pod of the celandine Fia. 169. — Winged Fruits. (Fig. 271), or several- Ma Meee celled, as in the fruit of the poppy, the morning-glory, and the jimson weed (Fig. 271). 224 FOUNDATIONS OF BOTANY 241. Dry Fruits and Fleshy Fruits. —In all the cases discussed or described in Sects. 238-240, the wall of the ovary (and the adherent calyx when present) ripen into tissues which are somewhat hard and dry. Often, how- ever, these parts become developed into a juicy or fleshy mass by which the seed is surrounded ; hence a general division of fruits into dry fruits and fleshy frutts. 242, The Stone-Fruit. — In the peach, apricot, plum, and cherry, the perecary or wall of the ovary, during the proc- ess of ripening, becomes con- verted into two kinds of tissue, the outer portion pulpy and edible, the inner portion of almost stony hardness. In common language the hard- ened inner layer of the peri- carp, enclosing the seed, is : called the stone (Fig. 170), Fic. 170.—Peach. Longitudinal hence the name stone-fruits. ener re 243. The Pome. — The fruit of the apple, pear,-and quince is called a pome. It con- sists of a several-celled ovary, — the seeds and the tough membrane surrounding them in the core, — enclosed by a fleshy, edible portion which makes up the main bulk of the fruit and is formed from the much-thickened calyx, with sometimes an enlarged receptacle. In the apple and the pear much of the fruit is receptacle. 244. The Pepo or Gourd-Fruit.— In the squash, pump- kin, and cucumber, the ripened ovary, together with the thickened adherent calyx, makes up a peculiar fruit (with a firm outer rind) known as the pepo. The relative bulk THE FRUIT 225 of enlarged calyx and of ovary in such fruits is not always the same. How does the amount of material derived from fleshy and thickened placente in the squash compare with that in the watermelon? Z 245. The Berry.— The berry proper, such as the tomato, grape, persimmon, gooseberry, currant, and so on, consists of a rather thin- skinned, one- to several- celled, fleshy ovary and its contents. In the first three cases above mentioned the calyx forms no part of the fruit, but it does in the last two, and in a great number of berries. The gourd-fruit and the hesperidium, such as the Fria. 171. — Cross-Section of an Orange. ‘ a, axis of fruit with dots showing cut-off orange (Fig. 1 71), lemon, ends of fibro-vascular bundles ; p, parti- : tion between cells of ovary; S, seed; and lime, are merely de- e, cell of ovary, filled with a pulp com- : : : posed of irregular tubes, full of juice; cided modifications of the 0, oil reservoirs near outer surface of rind; e, corky layer of epidermis. berry proper. 246. Aggregate Fruits.— ‘The raspberry, blackberry (Fig. 172), and similar fruits consist of many carpels, each of which ripens into a part of a compound mass, which, for a time at least, clings to the receptacle. The whole is called an aggregate fruit. To which one of the preceding classes does each unit of a blackberry or of a raspberry belong? / What is the most important difference in structure between a fully ripened raspberry and a blackberry ? 226 FOUNDATIONS OF BOTANY 247. Accessory Fruits and Multiple Fruits. — Not infre- quently, as in the strawberry (Fig. 172), the main bulk of the so-called fruit consists neither of the ripened ovary nor its appendages. Such a combination is called an accessory fruit. Examine with a magnifying glass the surface of a small, unripe strawberry, then that of a ripe one, and finally a section of a ripe one, and decide where the separate fruits of the strawberry are found, what kind of fruits they are, and of what the main bulk of the straw- berry consists. < The fruits of two or more separate flowers may blend into a single mass, which is known as a multiple fruit. Perhaps the best-known edible examples of this are the Fic. 172. —I, Strawberry ; II, Raspberry ; III, Mulberry, mulberry (Fig. 172) and the pineapple. The last-named fruit is an excellent instance of the seedless condition which not infrequently results from long-continued culti- vation. 248. Summary.-— The student may find it easier to retain what knowledge he has gained in regard to fruits if he copies the following synopsis of the classification of fruits, and gives an example of each kind. Fruits THE FRUIT Composition Texture Mode of. disseminating seed Simple. Aggregate. Accessory. Multiple. r Fleshy Stone Dry k Indehiscent Delriscent \ CORSE (ee RS ee Se Pe 227 CHAPTER XIX THE CLASSIFICATION OF PLANTS! 249. Natural Groups of Plants. — One does not need to be a botanist in order to recognize the fact that plants naturally fall into groups which resemble each other pretty closely, that these groups may be combined into larger ones the members of which are somewhat alike, and so on. For example, all the bulb-forming spring buttercups 2 which grow ina particular field may be so much alike in leaf, flower, and fruit that the differences are hardly worth mentioning. The tall summer buttercups ? resemble each other closely, but are decidedly different from the bulbous spring-flowering kind, and yet are enough like the latter to be ranked with them as buttercups. The yellow water-buttercups* resemble in their flowers the two kinds above mentioned, but differ from them greatly in habit of growth and in foliage, while still another, a very small-flowered kind,’ might fail to be recognized as a buttercup at all. The marsh marigold, the hepatica, the rue anemone, and the anemone all have a family resemblance to butter- cups,® and the various anemones by themselves form another group like that of the buttercups. 1 See Warming and Potter’s Systematic Botany, Strasburger, Noll, Schenk, and Schimper’s Text-Book of Botany, Part II, or Kerner and Oliver, Vol. II, pp. 616-790. 2. bulbosus. % R. acris. 4 R. multifidus. 5 R. abortivus. 6 Fresh specimens or herbarium specimens will show this. 228 THE CLASSIFICATION OF PLANTS 229 250. Genus and Species. —Such a group as that of the buttercups is called a genus (plural genéra), while the various kinds of buttercups of which it is composed are called species. The scientific name of a plant is that of the genus followed by that of the species. The generic name begins with a capital, the specific does not, unless it is a substantive. After the name comes the abbreviation for the name of the botanist who is authority for it; thus the common elder is Sambucus canadensis, L., L. standing for Linneus. Familiar examples of genera are the Violet genus, the Rosé genus, the Clover genus, the Golden-rod genus, the Oak genus. The number of species in a genus is very various,—the Kentucky Coffee-tree genus con- tains only one species, while the Golden-rod genus com- prises more than forty species in the northeastern United States alone. 251. Hybrids. — If the pollen of a plant of one species is placed on the stigma of a plant of the same genus but a different species, no fertilization will usually occur. Ina large number. of cases, however, the pistil will be ferti- lized, and the resulting seed will often produce a plant intermediate between the two parent forms. This proc- ess is called hybridization, and the resulting plant a hybrid. Many hybrid oaks have been found to occur in a state of nature, and hybrid forms of grapes, orchids, and other cultivated plants, are produced by horticul- turists at will. 252. Varieties. — Oftentimes it is desirable to describe and give names to subdivisions of species. All the culti- vated kinds of apple are reckoned as belonging to one spe- cies, but it is convenient to designate such varieties as the 230 FOUNDATIONS OF BOTANY Baldwin, the Bellflower, the Rambo, the Gravenstein, the Northern Spy, and so on. Very commonly varieties do not, as horticulturists say, “come true,” that is to say, the seeds of any particular variety of apple not only are not sure to produce that variety, but they are nearly sure to produce a great number of widely different sorts. Varie- ties which will reproduce themselves from the seed, such as pop-corn, sweet corn, flint-corn, and so on, are called races. Only long and careful study of plants themselves and of the principles of classification will enable any one to decide on the limits of the variety, species, or genus, that is, to determine what plants shall be included in a given group and what ones shall be classed elsewhere. 253, Order or Family. — Genera which resemble each other somewhat closely, like those discussed in Sect. 249, are classed together in one order or family. The particu- lar genera above mentioned, together with a large number of others, combine to make up the Crowfoot family. In determining the classification of plants most points of structure are important, but the characteristics of the flower and fruit outrank others because they are more constant, since they vary less rapidly than the characteris- tics of roots, stems, and leaves do under changed condi- tions of soil, climate, or other surrounding circumstances. Mere size or habit of growth has nothing to do with the matter, so the botanist finds no difficulty in recognizing the strawberry plant and the apple tree as members of the same family. This family affords excellent illustrations of the mean- ing of the terms genus, species, and so on. Put in a THE CLASSIFICATION OF PLANTS 231 tabular form, some of the subdivisions of the Rose family are as follows : The Rose family includes (among many. others) : ( L Plum genus Rose genus Pear genus r L Peach species (many varieties). Garden plum species (many varieties). Wild black cherry species. | Garden red cherry species (many varieties). (Dwarf wild rose species. Sweet-brier species. i Tea variety. India rose species * c eae | Pompon variety, etc. | Damask rose species. ( Seckel variety. Pear species Bartlett variety. Sheldon variety, etc. Baldwin variety. Greening variety. Apple species Bellflower variety. Northern Spy variety, etc. 254, Grouping of Families.— Families are assembled into classes, and these again into larger groups. The details of the entire plan of classification are too compli- cated for any but professional botanists to master, but an outline of the scheme may be given in small space. The entire vegetable kingdom is divided into two great divisions, the first consisting of eryptogams or spore-plants, the second of phanerogams or seed-plants. Here the rela-_ tions of the various subdivisions may best be shown by a table. 1 This is, of course, only for consultation, not to be committed to memory. FOUNDATIONS OF BOTANY 232 un ‘dnoisqus 19430Ue UI oAIsNpOUr or-8 pus ‘2467p se uMoUY dnoisqns & ul peoeld aexzo ore soyLydol[ Vy} 94} Fo sATSNTOUL J-g SESSBID 1 *sassoul qniQ ‘saypipodoohT ‘gs syunjd aytp-usaf ‘soysni SuLmoog ‘sagpjasinbay °Z oy Io SULAHAOMIAALT ‘suleg ‘saypowy “T SSVI AI anouy squnid ay i ier iadtiag Wguks I -ssout IO ea # ‘S}IOMIEATT ‘woundazT “[ SSVIO ay aoa uayay @ S@ UMOUY ‘| i ‘SSVI9 WOTeUTquIod yy ‘drysseujaed ut > sauayovyT IVALLVTION ay] @ Surpesl wuny pur wsTy ‘oqo ‘sopgnay ‘sysvaX ‘sazaahwoosy “OT » ‘sTooyspeoy pure ‘sygna ‘sMepT I ‘sa20hwowpisvg “6 » ek 1 - oqo ‘sprnoyy ‘saaahmoahyg ° ‘eSye pey ‘waohydopoyy - ese umoig ‘waohydonyg * 6 i -ojdhiso wnynyjaa ssayfvay 9 -eBpe weerxy ‘waokydo1yy) *G F § G T IO SHLAHAOTIVH, TI an0uy ” e ‘summos-puod pue spruisag ‘aypbnfuo) * “‘suLOqRT(y ‘sazvIn)povg ° “syued-uoissty ‘waokydozyog ° “elreyoeg ‘sajaohwmozyog * 5 ssv19 J syunjd poipowsnjd 10 “Buny-ouys uouIMOD ‘savajsvboxhpy SSVIQ > SHLAHAOTIVHLOXAW] J an04y “WMOpZUTY 919e}939A 94} JO VOLJLOMISSLTO 94} JO GL “GCZ i > SINVTg-au0dg uO SWVDOLAANY I NOISIAIG, THE CLASSIFICATION OF PLANTS 233 Crass I .|GYMNOSPERMS or seed-plants with naked ova- ries, such as pines, spruces, cedars, and many other evergreen trees. Drvision II . ( Susciass I PHANEROGAMS OR Cc II | MoNnocoTyLEDONOUS LASS SEED-PLANTS | ANGIOSPERMS OF PLANTS seed-plants with Susciass II closed ovaries’ DICOTYLEDONOUS l PLANts. 256. The Groups of Cryptogams. — The student is not to suppose that the arrangement of cryptogams into the four great groups given in the preceding table is the only way in which they could be classed. It is simply one way of dividing up the enormous number of spore-bearing plants into sections, each designated by marked character- istics of its own. But the amount of difference between one group and another is not always necessarily the same. The pteridophytes and the bryophytes resemble each other much more closely than the latter do the thallo- phytes, while the myxothallophytes are but little like other plants and it is extremely probable that they are really animals. The classes given in the table do not embrace all known cryptogams, but only those of which one or more repre- sentatives are described or designated for study in this book. Lichens in one sense hardly form a class, but it is most convenient to assemble them under a head by them- selves, on account of their extraordinary mode of life, a partnership between alge and fungi. 257. The Classes of Seed-Plants.— The gymnosperms are much less highly developed than other seed-plants. 234 FOUNDATIONS OF BOTANY The angiosperms constitute the great majority of seed- plants (or, as they have been more commonly called, flowering plants). Only one family of gymnosperms (the Conifere) is described in Part III of this book, though there are other families of great interest to the botanist, but with no representatives growing wild in the Northern United States. When people who are not botanists speak of plants they nearly always mean angiosperms. This class is more interesting to people at large than any other, not only on account of the comparatively large size and the con- spicuousness of the members of many families, but also on account of the attractiveness of the flowers and fruit of many. Almost all of the book which precedes the present chapter (except Chapter XII) has been occupied with seed-plants. Seed-plants of both classes frequently offer striking examples of adaptation to the conditions under which they live, and these adaptations have lately received much study, and are now treated as a separate department of botany (see Part IT). CHAPTER XX TYPES OF CRYPTOGAMS; THALLOPHYTES 258. The Group Thallophytes.— Under this head are classed all the multitude of cryptogams which have a plant-body without true roots, stems, or leaves. Such a plant-body is called a thallus. In its simplest form it con- sists of a portion of protoplasm not enclosed in a cell-wall and without much of any physiological division of labor among its parts (Fig. 125). Only a little less simple are such enclosed cells as that of Plewrococcus (Sect. 278) or one of the segments of Oseillatoria (Sect. 268). The most complex thallophytes, such as the higher alge and fungi, have parts definitely set aside for absorption of food and for reproduction. The latter is sometimes accomplished by more than one process and is occasionally aided by some provision for scattering the reproductive bodies or spores about when they are mature. 259. Spores. — Before beginning the study of spore- plants it is well for the student to know what a spore is. A spore is a cell which becomes free and capable of develop- ing into a new plant. Spores are produced in one of two ways: either aserually, from the protoplasm of some part ; of the plant (often a specialized spore-producing portion), or sexually, by the combination of two masses of proto- plasm, from two separate plants, or from different parts of the same plant. 236 236 FOUNDATIONS OF BOTANY Asexually produced spores are sometimes formed, each by the condensation of the protoplasm of a single cell, as shown in Fig. 174, #. They are also formed by the con- tents of spore-cases breaking up into many spores (Fig. 1738, B; Fig. 210, D). Spores are sometimes produced by the spontaneous division of a mass of protoplasm into a small definite number of segments (Fig. 188, t). Spores which have the power of moving (swimming) freely are known as zoéspores (Fig. 179, B). Sexually produced spores are formed in many ways. One of the simplest modes is that shown in Fig. 178, resulting in zygospores. Other methods are illustrated in Figs. 185 and 187.1 THE STUDY OF SLIME MOULDS? 260. Occurrence. — Slime moulds occur in greenhouses, in tan- yards, or on old logs and decaying leaves in woods. They may be cultivated in the laboratory. : They have been described in their vegetative condition on page 179. 261. Examination with the Magnifying Glass. — Stemonitis is one of the most available genera to illustrate the fruiting of slime moulds. At maturity the motile protoplasm of the vegetative stage quickly transforms itself into numerous sporangia or spore-cases with dust- like spores. With the naked eye and with a inagnifying glass note the color, form, and feathery appearance of the spore-case of Stemo- nitis. The outer wall disappears at an early stage, leaving only an inner structure and spores. Sketch the general outline under a magnifying glass. 262, Examination with the Microscope.-— With a low power of the microscope sketch the network of branching hairs which com- pose the structure of the sporangium. Note the presence or absence 1 See Vine’s Student’s Text-Book of Botany, pp. 68-71. 2 This should logically precede Sect. 258. TYPES OF CRYPTOGAMS; THALLOPHYTES 237 of a central column. Have any of the branches free tips? With a power of 250 or more examine the spores. A much higher power may be used to advantage. Describe the surface of the spore. THE STUDY OF BACTERIA 263. Occurrence. — «Bacteria may occur anywhere but not every- where.” In water, air, soil, and almost any organic substance, living Fia. 173. — Spore-Cases of Slime Moulds. A,a group of spore-cases of Arcyria; B, a spore-case of Trichia, bursting open and exposing its spores to the wind, x 20; C, threads of the same, with spores between them, x 250. or dead, some species of plant belonging to the group Bacteria may occur. A small bunch of hay placed in a tumbler of water will, at a suitable temperature, yield an abundant crop in a few days or hours. Raw peas or beans soaked for a week or two in water in a warm place will afford a plentiful supply. 264, Cultures. — Pure cultures of bacteria are commonly made in some preparation of gelatine in sterilized test-tubes. Boiled potatoes serve a good purpose for simple (but usually not pure) cultures. Select a few small roundish potatoes with skins entire and boil in water for a sufficient time to cook them through. Cut them in halves with a knife well scalded or sterilized, i.e. freed from all living 238 FOUNDATIONS OF BOTANY organisms in a flame, and lay each on a saucer, with cut surface up, covering each with a glass tumbler. The tumblers and saucers should be well scalded or kept in boiling water for half an hour and used without wiping. Sterilization may be improved by baking them in an oven for an hour. 265. Inoculation. The culture media prepared as above may now be inoculated. Uncover them only when necessary and quickly replace the cover. Scrape a little material from the teeth, tongue, kitchen sink, floor of house or schoolroom, or any other place you may desire to investigate. With the point of a knife blade or a needle sterilized in a flame, inoculate a particle of the material to be cultivated into the surface of one of the potatoes. Several cultures ee greul Fig. 174. — Bacteria stained to show Cilia. A, Bacillus subtilis; B, Bacillus typhi (the bacillus of typhoid fever); C, Bacillus tetani (the bacillus which causes lockjaw) ; D, Spirillum undula; FE, Bacillus tetani forming spores. (All five are magnified 1000 diameters.) may be made in this way and one or more left uninoculated as checks. Another may be left uncovered in the air for half an hour. Others may be made with uncovered potatoes. Number each culture and keep a numbered record. Keep watch of the cultures, looking at them daily or oftener. As soon as any change is noticed on the surface of a culture, make a descriptive note of it and continue to record the changes which are seen. Note the color of the areas of growth, their size, outline, ele- vation above the surface, and any indications of wateriness. Any growth showing peculiar colors or other characters of special inter- est may be inoculated into freshly prepared culture media, using any additional precautions that are practicable to guard against contamination. TYPES OF CRYPTOGAMS; THALLOPHYTES 230 266. Microscopic Examination. — Examine some of the cultures. Place a particle of the growth on a slide, dilute it with a drop of clear water, and place a cover-glass over it. Examine with the highest obtainable power of the microscope, at least 3 in. objective. Note the forms and movements, also the sizes if practicable, of any bacteria that are found. THE STUDY OF OSCILLATORIA! 267. Occurrence. — Oscillatoria may occur floating in stagnant water or on damp soil in ditches, roadsides, dooryards, paths, or pots in greenhouses. Other nearly related plants occur on surfaces of ponds sometimes covering considerable areas or adhering in small spheres to submerged vegetation. Alge of this class are particu- larly noxious in water supplies, as they partake of the nature of bacteria, to which they are related. 268. Examination with the Microscope. — After washing a particle of Oscillatoria material in a drop of water to remove as much of the earth as possible, place it in a clean drop of water, pull to shreds with needles, cover, and examine under a power of 200 or more diameters. Note the color and compare it with chlorophyll green. The filament is not one plant, but each of the cells which com- pose it is one plant. They are packed together in the filament like coins and sometimes may be found separating singly. The usual mode of reproduction is by the separation of a number of adhering cells as a short filament from one end of a longer one, and this increases in length by the dividing of its individual cells. 269. Movement.— At ordinary temperatures, favorable to growth, movement may be observed in the filaments. Describe the move- ment. What has it to do with the name of the plant? 1 A genus of the class Schizophycez. 240 FOUNDATIONS OF BOTANY THE STUDY OF DIATOMS 270. Occurrence. — Diatoms of different species may be found in sediment in water in various kinds of places or mixed with or A B Fia. 175. — Schizophycex. A, a filament of Calothrix, reproducing by hormogonia, h, segmented portions which escape from the sheath of the filament ; B, Rivularia. (Both A and B greatly magnified.) adhering to fresh-water or ma- rine alge, in ponds and ditches or on sand or earth at the bottom of clear brooks. In the last place they may be detected with the eye, forming a yellow- ish coloring. They may often be obtained by straining hy- drant water. Where diatoms have been very abundant their remains sometimes form beds of rock, and fossil diatoms compose some of the polishing powders of commerce. 271. Microscopical Examina- tion of Diatoms. — Place a drop of water containing diatoms on a slide and put a cover-glass over it. Examine with a power of 200 or more diameters. Dia- toms occur singly, resembling triangles, wheels, boats, rods, and. a great variety of other forms (Fig. 176), or adhering in long bands, as spokes of a wheel, etc. The boat-shaped kinds are among the common- est. The color of the contents: is yellowish. The cell-wall is encrusted with a shell of silica whose surface is covered with beautiful markings, dots or lines, which are conspicuous in some species, in others so minute that the most powerful microscopes are required to detect them. By boiling TYPES OF CRYPTOGAMS ; THALLOPHYTES 241 in nitric acid, the cellulose wall and its contents may be destroyed and the markings of the siliceous shell more easily observed. Each diatom consists of a single cell. 272, Movements of Diatoms. — Living diatoms exhibit a peculiar power of movement. Jn the boat-shaped species the movement is much like that of a row-boat, forward or backward. THE STUDY OF SPIROGYRA 273. Occurrence. — Spirogyra, one of the plants commonly known as pond-scum, or “frog-spit,” occurs widely distributed throughout the country in ponds, springs, 6 and clear streams. It is of a green or yellowish-green color, and in sunny weather usually floats on or near the surface of the water, buoyed up by the numerous oxygen bubbles which it sets free. It may be found flourishing in unfrozen springs, even in midwinter. 274. Examination with the Magnifying Glass.1— Float a little of the material in a white plate, using just water enough to cover the bottom of the latter. Study with the magnifying glass and note the green color of the threads and their great length as compared with their thick- ness. Are all the filaments about equal to each other in diameter? Handle a mass of the material and describe how it feels between the fingers. ’ 275, Examination with the Microscope. — Mount in water under a large cover-glass and examine first with a power of about 100 Fic. 176.— A Group of Diatoms. A, Achnanthes; B, Cocconema; C, Meridion; D, Pleurosigma. 1 Consult Huxley’s Biology and Spalding’s Introduction to Botany. 242 FOUNDATIONS OF BOTANY diameters, then with a power of 200 diameters or more. Note the structure of the filaments. Of what is each made up? Compare with the structure of Oscillatoria. Move the slide so as to trace the whole length of several filaments, and, if the unbroken end of one can be found, study and sketch it. Study with the higher power a single cell of one of the larger filaments and ascertain the details of structure. Try to discover, by focusing, the exact shape of the cell. How do you know that the cells are not flat? Count the bands of chlorophyll. The number of bands is an important characteristic in dis- tinguishing one species from another. Run in five-per-cent salt solution at one edge of the cover-glass (withdraw- ing water from the other edge with a bit of blotting paper). If any change in the appearance of the cell becomes evident, make a sketch to show it. What has happened to the cell-con- _ tents? Explain the cause of the Fic. 177.— Process of Cell-Multi- plication in a Species of Pond- change-by reference to what you know Scum. (Considerably magnified.) of osmose. A, portion of a filament partly On a freshly mounted slide run ae eee under the cover-glass iodine solution, completed, a new partition of a little at a time, and note its action neue aes wees ete A a on the nucleus. Is any starch shown tied, Sica aicous oe to be present? If so, just how is it d, general cell-wall ve, and a distributed through the cell? ag asap ean — 276. Reproduction of Spirogyra. — The reproductive process in Spirogyra is of two kinds, the simplest being a process of jission, or cell- division. The nucleus undergoes a very complicated series of transformations, which result in the division of the protoplasmic contents of a cell into two independent portions, each of which is at length surrounded by a complete cell-wall of its own. In Fig. 176 TYPES OF CRYPTOGAMS; 'THALLOPHYTES 248 the division of the protoplasm and formation of a partition of cellulose in a kind of pond-scum are shown, but the nucleus and its changes are not represented. Another‘kind of reproduction, namely by conjugation, is found in Spirogyra. This process in its simplest form is found in such unicellular plants as the desmids (Fig. 178). Two cells (apparently precisely alike) come in contact, undergo a thinning-down or absorp- tive process in the cell-walls at the point of contact, and finally blend , their protoplasmic cell-contents, as shown in the figure, to form a mass known as @ spore, or more accu- rately a zygospore, from which, after I Fie. 178. — Conjugation of Cells of Green Alge. (Much magnified.) I. Conjugation of Desmids. .A,a single plant in its ordinary condition; B, empty cell-wall of another individual; C, conjugation of two individuals to form a spore by union of their cell-contents. Il. Conjugation of Spirogyra. A, two tilaments of Spirogyra side by side, with the contents of adjacent cells uniting to form spores, z. At the bottom of the figure the process is shown as beginning at the top as completed, and the cells of one filament emptied; B, a single filament of another kind of Spirogyra, containing two spores, one lettered z. (A magnified 240 diameters, B 150 diameters.) @ period of rest, a new individual develops. In Spirogyra each cell of the filament appears to be an individual and can conjugate like the one-celled desmids. It is not easy to watch the process, since the spore-formation takes place at night. It is possible, 244 FOUNDATIONS OF BOTANY however, to retard the occurrence of conjugation by leaving the Spirogyra filaments in very cold water over night, and in this way the successive steps of the conjugating process may be studied by daylight. In such ways the series of phenomena shown in Fig. 178, II, has been accurately followed. If the student cannot follow these operations under the microscope, he may, at least, by looking over the yellower portions of a mass of Spirogyra find threads con- taining fully formed zygospores, like those shown in B, Fig. 178. THE STUDY OF PLEUROCOCCUS 277. Occurrence. — Pleurococcus may be found on old fences, roofs, and many similar places, particularly on the bark of the north side of trees. The individual plants cannot be detected by the naked eye, but when grouped in masses they form a powdery green covering over indefinite areas of bark. Plenty are seen where it is moist. 278. Microscopical Examination of Pleurococcus. — Scrape a minute quantity of Pleurococcus from a specimen on bark, place it in a drop of water on a slide, distributing it slightly in the water, lay on it a cover-glass and ex- amine with a power of 200 or more diameters. Sketch with the cam- era lucida one of the largest cells, some of intermediate size, and one of the smallest, beside several divisions of the stage microm- eter. Note the clearly de- fined cell-wall of cel- A, a spherical cell of the stillform; B, a motile cell lulose, enclosing the with its protoplasm enclosed in a loose cell-walland protoplasmic contents, provided with two cilia. ; Fic. 179.— Two Cells of Protococcus. (Greatly magnified.) usually green through- out. Do any cells show a nucleus like that in Fig. 179, A? Test the cells with iodine solution for starch. TYPES OF CRYPTOGAMS; THALLOPHYTES 245 Note that in reproduction the cell-contents in many individuals has divided into two parts which become separated from each other by a cellulose partition. Each of these again divides, and the proc- ess continues until thirty-two or more cells may be found in one mass or they may fall apart at an earlier stage. 279. Nutrition of Pleurococcus. -—- Pleurococcus can flourish only with an abundance of light and moisture. In daylight it can absorb carbon dioxide and fix carbon (giving off the oxygen at the same time as bubbles of oxygen) and can assimilate mineral substances. It is a capital example of an individual cell capable of independent existence. 280. Motile Forms. — No motile form is known in Pleurococcus. Hematoccus, often known as Protococcus (Fig. 179), is a better object for study than Pleurococcus. It may sometimes be found in water of stagnant pools, particularly those which contain the drainage of barnyards or manure-heaps, in mud at the bottom of eaves-troughs, in barrels containing rain-water, or in water standing in cavities in logs or stumps. Its presence is indicated by a greenish or some- times by a reddish color. It is sometimes found in an actively swimming condition, in which case each cell is called a zodspore. THE STUDY OF VAUCHERIA 281. Occurrence. — Species of Vaucheria are found in ponds, streams, and pools, immersed or floating like Spirogyra and at all seasons may be sought in greenhouses, where they grow on the moist earth of beds and pots, forming a green felt. 282. Examination with the Magnifying Glass.-The magnifying glass will show the growth of Vaucheria to consist of numerous green filaments similar to those of Spirogyra. Select a small portion and spread out the filaments carefully in a drop of water on a slide. Does the glass reveal any indications of cross-partitions, of branch- ing, or of fruiting organs as short lateral branches? Does it show the form or arrangement of the green coloring matter? 283. Examination with the Microscope. — Prepare as directed for the magnifying glass and place a cover-glass over the prepara- tion, with sufficient water. With the lowest power observe the 246 FOUNDATIONS OF BOTANY continuity of the cell-cavity and (in young plants growing on soil) search for root-like portions, in those growing in water for branch- ing portions, and fruiting organs in the form of swellings or short lateral branches. With a power of about thirty to sixty diameters sketch a selected plant of moderate extent as nearly complete as possible or else Fic, 180.— Vaucheria synandra. A, a filament with archegonia and antheridia (considerably magnified); B, part of same much more highly magnified; 0, oJgonium; a, antheridium; C, a Jater stage of B; D, end of a filament with a zodspore, z, escaping (highly magnified). sketch a portion showing the branching and a rootlike portion. Note. and indicate the absence or presence and arrangement of chlorophyll. Can Vaucheria probably use carbon dioxide? 284, Reproduction in Vaucheria.— Make an outline sketch of fruiting organs, if found. See if any filaments can be found with the contents massing or escaping at the tips. In some species TYPES OF CRYPTOGAMS; THALLOPHYTES 247 zoéspores are formed in this way, having their entire surface clothed with cilia. They are the largest motile cells known. In other spe- cies a portion of the filament is separated and cut off by a cell-wall. Such spores soon germinate and may be found in various stages of growth. They often serve for propagation through several genera- tions before spores are produced by fertilization. With a power of about 200 diameters sketch a portion of a fila- ment to show the form and location of chlorophyll. Sketch the fruiting organs in detail, if any can be found.t Antheridia and odgonia are-formed near together on the same filament. The antheridium is a cell forming the terminal portion of a short branch, which is rather slender, straight or curved. Its contents form numerous minute antherozoids, each with two cilia. The cilia can be seen only with great difficulty, if at all, but their presence is indicated by their active movements. The odgonium is a short, somewhat spheroidal branch separated by a cross-partition at the base. The cell-wall becomes ruptured at the tip, allowing the entrance of the antherozoids by which it is fertilized. After fertilization a cell-wall is formed about the odsphere, and it matures as an odspore and enters upon a period of rest. THE STUDY OF NITELLA 285. Occurrence. — Nitella is a green plant growing attached to the bottom of ponds and streams, usually in shallow water. It is not common everywhere but is widely distributed. Chara is similar and may be used as a substitute but is more complicated. 286. General Aspect.— With the naked eye and a magnify- ing glass note the general aspect of Witella, the length of the stem- like portions, from the root-like parts to the tip, the length of some of the joints (internodes), the arrangement of leaf-like and branch- like portions. 287. Protoplasm. — Examine the cells of stems or leaves under a low power. Select a vigorous cell of moderate size and examine 1 Goebel states that the formation of the fruiting organs begins in the ewen- ing, is completed the next morning, and that fertilization takes place during the day between ten and four o’clock. 248 FOUNDATIONS OF BOTANY under a power of 200 or more diameters. Select the terminal cell of the leaf if Chara is used. The protoplasm is nearly colorless but usually contains bodies which can be seen moving in the current of protoplasm. The protoplasm will show normal activity at the temperature of a comfortable living room. By focusing, see if the current of protoplasm can be detected moving in more than one direction. Note the form and arrangement of the chlorophyll and any places lacking chloro- phyll, and see if you can tell whether the arrangement has any relation to the current of protoplasm. With a low power trace the course in several cells. How many cells con- stitute each internode of Nitella? If Chara is used, internodes will be found to be covered with a layer of many corticating cells. Under a high power compare the general structure of node and internode and see if the attachment of leaves and branches can be clearly determined. Compare the tip of a leaf with the tip of a stem or branch if the material permits. Are the fruiting organs produced on the stems or the leaves? 288. Antheridia.—_The antheridia are globular bodies, bearing male fertilizing cells and becoming red at maturity (Fig. 182), Eight cells compose the outer wall. They have radial lines indicating folds and Fig, 181.—End of a Main join one another by irregular sutures. Note Shoot of Chara. (About a round spot in the middle of each cell pases ae: which marks the point of attachment within of the stalk on which antherozoid-producing cells are borne. 289. Odgonia.— The egg-shaped fruits, known as odgonia (Fig. 182), are borne near the antheridia in monecious species. Count thé number of pointed cells which constitute the “crown” of the fruit. Does each tip consist of one or two short cells? Examine TYPES OF CRYPTOGAMS; THALLOPHYTES 249 the surface of the enveloping cells which enclose the spore. What is their number and form? What is their relation to the cells form- ing the crown? Focus so as to see the large egg-cell (odsphere or odspore) which constitutes the center of the fruit. Can you determine anything regarding its contents? Search for young odgonia and if practicable describe and draw them in several stages of development. Their structure can be seen much more easily than that of the antheridia. Make drawings to illus- trate various details of structure. 290. Characea. — Miella and Chara are the genera composing the group Chara- cee, a group of green alge differing widely from any others. They show in a won- derful manner simplicity of cell-structure with a high | degree of organization. Fic. 182. — Part of a Leaf of Fig. 181. (Considerably magnified.) Scarcely less wonderful are a,antheridium ; 0,o$gonium. At the the care and precision with ‘ight are a young antheridium and which botanists have worked § ""°°""™ out their life history. Asastudy in evolution the Characee may be considered as representing the highest develop- ment attained along the line of filamentous green alge, which, while preserving their algal characteristics, are comparable in a remarkable degree with moss- and fern- plants and with seed-plants. Every cell in the plant has been accounted for and is understood in regard to origin, relationship, and function. With harmony of structure throughout, it has organs comparable to root, stem, and leaf in seed-plants, each with characteristic structure and 250 FOUNDATIONS OF BOTANY mode of growth. The stem has nodes and internodes. The stem increases by the growth of an apical cell, but growth in length depends chiefly on the elongation of each internodal cell instead of the multiplication of numerous internodal cells. THE STUDY OF ROCKWEED! 291. Occurrence. The common rockweed is abundant every- where on rocks, between high and low tide, on the New England coast and southward. 292. The Frond. — A plant of rockweed consists mostly of a growth which is some- what leaf-like, but, in fact, stem and leaf are not separately developed, and the growth is therefore called a thallus. This combined stem and leaf has. many flat leathery branches which are buoyed up in the water by air-bladders. Cut one of the bladders openand note its form and appearance. Note whether they occur singly or how grouped. Note the prominent midrib running through- out the middle of each branch. Examine the swollen tips of some of the branches and note their peculiarities. Sketch a portion #) of a frond to show the characteristics so far noted. 293. Reproduction. — Cut across through the middle of one of the swollen fruiting tips. Note the fruiting papille (concep- tacles) as they appear in this section, and make a simple sketch to show their position. Select some plants with brighter colored Fig. 183.—Part of Thallusof tips and some less bright, if any di a Rockweed (Fucus platy- Pp ope = y difference carpus), naturalsize. The : a i two uppermost branchlets 1 Fucus vesiculosus is the most available species. are fertile. Others may be substituted. TYPES OF CRYPTOGAMS; THALLOPHYTES 251 can be detected. After making the microscopic examination which follows, note what correspondence of structure B with color has been observed. Cut very thin sections through fruiting tips from different plants, keeping those from each plant separate. Be sure that some of the cuts pass through the conceptacle as near the middle as possible. Examine with a power of about sixty diameters sections from different fronds, searching for one kind containing rather large egg-shaped cells and another con- taining bundles of numerous smaller yo, 194. —Rockweed (Fucus). sac-shaped cells. With a power of 200 4 antheridia borne on branch- diameters study the details of the sec- ing hairs, x 160; B, anthero- tions. Note the character of the cells 7148 from same, * 980. forming the surface of the frond, those of the inner structure, and those limit- ing the cavity of the conceptacle. Ina conceptacle cut through the middle note the form of the orifice. Examine the slender hairs or filaments (paraphyses) which, arising at right angles, line the walls of the conceptacle. 294. Odgonia and Antheridia. — In conceptacles containing egg-shaped cells (odgonia) note the form, mode of attachment (ses- sile or stalked), and dif- ferent stages of develop- ment. At maturity the contents are divided, forming eight odspheres; but not all can be seen Fie. 185.— Rockweed (Fucus). A, oégonium, its contents dividing into eight odspheres, at once, some being be- x 160; B, an odsphere, escaped, surrounded by an neath the others, therozoids, x 160, 252 FOUNDATIONS OF BOTANY In conceptacles of the other kind examine the numerous small sac-shaped cells (antheridia). At maturity the contents of each divide to form nunierous very minute motile antherozoids, each with two delicate hairs or cilia. Dissect, by picking and by friction under cover-glass, a bunch of antheridia and note the branching fila- ments upon which they are borne. Make drawings to illustrate the various points of structure. 295. Number of Antherozoids required for Fertilization.—The bulk of an odsphere has been estimated equal to that of thirty thousand to sixty thousand antherozoids, but apparently an odsphere may be fer- tilized by only one antherozoid. Yet a large number swarm around each odsphere after both have escaped from the con- ceptacies, and often their movements are so active as to cause the rotation of the odsphere. The process of fertilization may be discerned in fresh material by squeezing oéspheres and antherozoids from theix respective conceptacles into a drop of water on a slide. In some species, as Fucus platgcarpus (Fig. 186), antheridia and odgonia are found in the same conceptacle. Fic. 186.— Transverse Section of Conceptacle of a Rockweed (Fucus platycarpus). (x about 35.) h, hairs ; a, antheridia; 0, odgonia, TYPES OF CRYPTOGAMS; THALLOPHYTES 258 THE STUDY OF NEMALION 296. Occurrence. — Seven or eight species of Nemalion are known in the world, but only one! is widely diffused, being found in Europe and on the New England coast from Rhode Island northward. It grows in salt water attached to exposed rocks at low-water mark. Nemation represents the largest of the groups of alge, nearly all of which live in salt water and have the characteristic color ; but afew live in fresh water. 297. Color.— Fresh specimens or those properly dried for the herbarium show the color which is characteristic of the great group to which Nemalion belongs. Dried specimens of «Jrish moss” (Chondrus) and many other species furnish good illustrations. There are many variations of shade and intensity. Place a piece of afresh or dried specimen of some species in a beaker of fresh water over night or longer and note the color of the solution and of the treated specimen. Treat another piece similarly with alcohol. A few genera related to Nemalion grow in fresh water. What do you infer regarding their color? 298. Form and General Character.— Examine specimens of Nemalion and note the size, shape, mode of branching, nature, or consistency of their substance. Examine a fragment of the plant with a power of about sixty diameters and note how the structure differs from what it appears to be to the naked eye. Do cells appear more densely packed or differently colored at any points? 299. Structure. — From a small portion of the plant cut thin longitudinal and transverse sections or pull it to pieces with needles so as to expose the inner portion. Place on a slide under a cover- glass in a drop of water. With a power of about 250 diameters or more examine the general structure of the frond, as shown by a slide prepared as above. Note the central portion (azis) of the frond as dissected out, consisting of long, slender, thread-like cells. Examine and draw the branching rows of cells which, radiating from the axis, form the surrounding outer structure of the frond. Note the tips of these branches and look for the fruiting organs and fruit (spores). 1 Nemalion multifidum. 254 FOUNDATIONS OF BOTANY Fic. 187.— Portions of Thallus of a Red Alga (Chantransia). (Much magnified.) A, filaments with antheridia, a; B, young recep- tive hair, or trichogyne,t; C and D, successive stages in the growth of the clustered fruit, f. 300. Organs for Repro- duction. — The fruiting organs are to be sought on the radiating branching filaments and are usually produced in great abun- dance during the summer. Various stages of develop- ment may be expected at a given time. The anther- ozoids are small spheres without cilia, non-motile, with a thin cell-wall. Look for cells in which they are formed (antheridia), occur- ring in groups at the tips of the branches. Compare these with the vegetative cells. x 301. Spore-Production. —Look for spore-producing organs in various stages. In the young stage at the time of fertilization, an- therozoids, carried by cur- rents of water, may be found adhering. Note the shape of the tip (trichogyne) and the base (carpogonium), and find whether there is any partition separating them at this stage.. Draw or describe a few later stages in development, and note the arrangement of the spores at maturity. Are they naked or enclosed in any sort of envelope? Are they arranged in masses, chains, or otherwise? TYPES OF CRYPTOGAMS; THALLOPHYTES 255 302. Other Floridee.— Nemalion represents one of the simplest modes of fruiting in the red alge. In others there is great variety in structure and great complication in the mode of fruiting. Some species of Polysiphonia (or Dasya) may well be studied in compari- son with Nemalion and in further illustration of this important group.! Understanding that a siphon, in alge, is a row of cells, end to end, study the structure of a plant of Poly- siphonia as illustrating its name. How many siphons are there? Do the main branches have any other cells covering the surface (cor- ticating cells) ? Note the tufts of repeatedly forking, one- siphoned filaments. 303. Fruiting of Polysiphonia. — The anther- idia are to be sought on the branching fila- ments just mentioned. Note how they differ from those of Nemalion. The clustered fruits or cystocarps will be recognized as ovoid- ©6@ globose or urn-shaped bodies attached externally to the frond. Note whether ® the group of spores is naked or otherwise, © whether the spores are produced singly or in chains ; how attached; shape. “Many Floride@ have another kind of = fruiting bodies, spores produced without eae fertilization, codrdinate with the asexual —_y spores of Wemalion Greatly spores of black mould (see Sect. 308). magnified); B, portion of In Floridee such spores are usually ee of a red alga, Lejo- isia, with tetraspores, %. found in fours and are called tetraspores. Are tetraspores usually found on separate plants? In Polysiphonia the tetraspores appear to be formed in threes (tripartite), the fourth being underneath the three. When found, describe their position and arrangement. 304. Alge.— Diatom, Oscillatoria, Pleurococeus, Spi- rogyra, Vaucheria, Nitella, Fucus, Nemalion, these eight 1 It is desirable also to exhibit fresh or pressed specimens of various genera to show their general aspect. 256 FOUNDATIONS OF BOTANY plants which we have just studied, are types of several families of plants which together make the great group called Alge. Something of its importance in nature is indicated by these facts: The number of known species is about 12,000. In size, the individuals in various species range from a single cell of microscopic dimensions, as in Pleurococeus, to the giant kelp of California which reaches, a length of more than 1000 feet. The form ranges from a simple spherical cell as in Pleurococeus to an extensive, branching cell in Vauwcheria and its allies, spécialized organs in the form of root, stem, leaf, air-bladder, and ‘fruiting organs in Sargassum, which isan ally of Fucus. The alge illustrate a series of modes of propagation from simple division in Oscillatoria to the union of two similar masses of protoplasm to form a spore in Spirogyra, the direct fertilization of a germ-cell by motile anthero- zoids in Vaucheria, Nitella, Fucus, the indirect fertilization of fruiting cells by non-motile antherozoids in Nemalion. In allies of the latter there are more intricate variations of the same mode. The alge fall into five natural groups based primarily on the mode of fruiting. In most cases color is codrdinate with class and may be relied upon as a superficial guide in grouping ; but there are a few exceptions, e.g., some fruit- ing like the red group are, nevertheless, green. The nutrition of the brown and the red alge is similar to that of the green alge, since the brown or red color merely conceals the green of the chlorophyll which is present in all and enables them all to take in and decom- pose carbon dioxide.! 1 See Murray’s Introduction to the Study of Seaweeds, pp. 4-6. London, 1895, TYPES OF CRYPTOGAMS; THALLOPHYTES 267 305. Classification of Types studied. DIATOMACES. Yellowish. Diatoms. CYANOPHYCEE. Blue-green or some similar color. Oscillatoria. CHLOROPHYCES. Green. Pleurococcus, Spirogyra, Vaucheria, Nitella. PHXOPHYCEA. Olive. Fucus. FLorIDEz. Red. Nemalion. Polysiphonia. THE STUDY OF BLACK MOULD (RHIZOPUS NIGRICANS) 306. Occurrence. — This mould may be found in abundance on decaying fruits, such as tomatoes, apples, peaches, grapes, and cher- ries, or on decaying sweet potatoes or squashes. For class study it may most conveniently be obtained by putting pieces of wet bread on plates for a few days under bell-jars and leaving in a warm place until patches of the mould begin to appear. 307. Examination with the Magnifying Glass.— Study some of the larger and more mature patches'and some of the smaller ones. Note : (a) The slender, thread-like network with which the surface of the bread is covered. The threads are known as hyphae, the entire network is called the mycelium. (6) The delicate threads which rise at intervals from the myce- lium and are terminated by small globular objects. These little spheres are spore-cases. Compare some of the spore-cases with each other and notice what change of color marks their coming to maturity. 308. Examination with the Microscope. — Sketch a portion of the untouched surface of the mould as seen (opaque) with a two-inch objective, then compare with Fig. 189, 258 FOUNDATIONS OF BOTANY Wet a bit of the mould, first with alcohol, then with water. Examine in water with the half-inch objective, and sketch a little of the mycelium, some of the spore-cases, and the thread-like stalks on which they are borne. Are these stalks and the mycelium filaments solid or tubular? Are they one-celled or several-celled? Mount some of the mature spore-cases in water, examine them with the highest obtainable power, and sketch the escaping spores. A Fia. 189, — Unicellular Mycelium of a Mould (Mucor Mucedo), sprung from a Single Spore. a, b, and c, branches for the production of spore-cases, showing various stages of maturity. (Considerably magnified.) Sow some of these spores on the surface of “hay-tea,”’ made by boiling a handful of hay in just water enough to cover it and then straining through cloth or filtering through a paper filter. After from three to six hours examine a drop from the surface of the liquid with a medium power of the microscope (half-inch objective) to see how the development of hyphze from the spores begins. Sketch. TYPES OF CRYPTOGAMS; THALLOPHYTES 259 After about twenty-four hours examine another portion of the mould from the surface of the liquid and study the more fully developed mycelium. Sketch. 309. Zygospores.— Besides the spores just studied, zygo- spores are formed by conju- gation of the hyphe of the black moulds. It is not very easy to find these in process of formation, but the student may be able to gather from Fig. 190 the nature of the process by which they are formed, —a process which can- not fail to remind him of the conjugation of pond-scum. THE STUDY OF WHEAT RUST (PUCCINIA GRAMINIS) 310. Occurrence. — Wheat rust is common on cultivated wheat and other grains, and also on many wild and culti- vated forage grasses. In fact, this or similar rusts occur on a very large number of grasses, and many species of such rusts are recognized. A rust may have one, two, or three kinds Fie. 190.— Formation of Zygospores ina Mould (Mucor Mucedo). 1, threads in contact previous to conjuga- tion; 2, cutting off of the conjugating cells, a, from the threads, 6; 3, a later stage of the process ; 4, ripe zygospore ; 5, germination of a zygospore and formation of aspore-case. (1-4 magnified 225 diam- eters, 5 magnified about 60 diameters.) of spores, and when three occur one is known as the cluster-cup stage and the others as red rust. and black rust, according to the usual approximate color of the spores. The rust called Puccinia graminis growing on wheat has its cluster-cup stage on the leaves of barberry in June. The spores from the cluster-cups are carried by the wind to the wheat, where they germinate and in a few days produce the 260 FOUNDATIONS OF BOTANY red rust. Wt a Plant from Shade _ WY Conditions to Sun >< Conditions. — It is characteristic of many kinds of forest trees that the young seedlings are much more tolerant of I II dense shade than the Fi. 227.1, a Shade-Plant (Clintonia) ; II, a Sun- Plant, Dog Fennel (Maruta). adult trees are. Sometimes their seeds will hardly germinate at all unless thoroughly shaded, and the young trees for the first few years flourish best in the shade. Afterwards most trees need a good deal of sunlight, but. they may live long with a scanty supply of light, The red spruce sometimes 3822 . FOUNDATIONS OF BOTANY Fic. 228.— An Epiphytic Fern (Platycerium) on a Tree Trunk. The more upright leaves next the trunk of the tree serve to collect water and to accumulate a deposit of decaying vegetable matter, while the outer leaves serve as foliage and bear spores. PLANT SOCIETIES 323 lingers on for fifty or a hundred years, reaching meantime a diameter of not more than two inches, and then, on getting more light, shoots up into a large and valuable timber tree.} 394. Epiphytes. — It is even easier for a plant to secure enough sunlight in a forest region by perching itself upon the trunk or branches of a tree than by climbing, as our wild grapevines and the great tropical lianas do. There is a large number of such perched plants, or epiphytes, embracing species of many different groups of seed-plants and of spore-plants. The fern shown in Fig. 228 is a good example of an epiphyte. Instances among seed-plants are the so-called Florida moss (Plate IV) and orchids like those in Fig. 13. 1See the Primer of Forestry, Part I, U.S. Department of Agriculture, 1899, pp. 33-35. CHAPTER XXV BOTANICAL GEOGRAPHY 395. Regions of Vegetation. — The earth’s surface (that of the land) has been described by one of the greatest of geographical botanists! as divided into twenty-four regions of vegetation. This classification takes account of all the principal continental areas which have a characteristic set of plants of their own, as well as of the most important islands. But a simpler arrangement is to consider the plant life of the earth as distributed among the following regions : The tropical zone. The temperate zones. The arctic zones. Mountain-heights, Bodies of water. Soot oO Any good geography gives some account of at least the land vegetation of the earth. It is necessary in the pres- ent chapter only to point out a few of the most important characteristics of the plants of the zones and other areas mentioned above and to give some reasons why the plant population of each has its special characteristics. 396. Tropical Vegetation. _— Within the tropics two of the great factors of plant life and growth, namely, light and heat, are found in a higher degree than elsewhere on the earth. Moisture, the third requisite, is in some 1 A. Grisebach. 824 BOTANICAL GEOGRAPHY 325 regions very abundant (over sixteen feet of rainfall in a year) or sometimes, in desert areas, almost lacking. We find here, accordingly, the greatest extremes in amount of vegetation, from the bare sands or rocks of the Sahara desert (Fig. 229) to the densely wooded basin of the Kongo and of the Amazon. Xerophytie plants, many of them with extremely. complete. adaptations for supporting life for long periods without water, are characteristic of tropical deserts, while many of the most decided hydro- phytes. among land-plants are found in the, dripping sub- FG, 229, — Hills of Drifted Sand in the Sahara, © tropical forest interiors. ‘Throughout a large part of the zone; reaching five degrees each way from ‘the equator, there are daily rains the year round. 397. Vegetation of the Temperate Zones. — We-are ‘all familiar in a general way with the nature of ‘thé plant life of the north temperate zone; that of the: south temperate is in most ways similar to our own: Most of the annuals and biennials are of a: medium type, ‘not decided xerophytes nor hydrophytes, and the ‘perennials are mainly tropophytes. There are no: desert areas so large or so nearly destitute of plants as those found in subtropical regions, neither are there any such luxuriant 326 FOUNDATIONS OF BOTANY growths as occur in the rainy forest regions of the tropics. On the other hand, the largest trees on earth, the “big trees,” or Sequoias (Fig. 82), occur in the temperate por- tion of North America, along the Sierra Nevada, and the taller, though less bulky, gum trees (Hucalyptus) of Australia grow in a warm temperate region. 398. Temperate Plant Societies due to Special Conditions of Soil. — Even where the climate ! is a moderate one as regards tem- perature and rainfall, peculiar soils may cause the assemblage of exceptional plant societies. ‘Some of the most notable of such societies in temperate North America are those of the salt marshes, the sand dunes, and the peat bogs. In salt marshes the water sup- ply is abundant, but plants do not readily absorb salt water by their Fr¢.230.— A Halophytic Plant roots, so that the plants which (enone), grow in salt marshes usually have something of the structure and appearance of xerophytes. Some of them are fleshy (Fig. 230), and some species are practically leafless. Sand dunes, whether along the seacoast or near the great lakes, offer a scanty water supply to the roots dur- ing much of the year, and the soil-water contains less of the raw materials for plant food than is offered by that of ordinary soils. Many grasses thrive, however, in these shifting sands (Plate I), and some, like the beach-grass BOTANICAL GEOGRAPHY 827 (Ammophila) of the Atlantic coast and the great lakes, will continue to eet upward as the sand is piled about them by the winds until they have risen to a level of a hundred feet above the start- an ing point. $ Peat bogs are especially characterized by the predominance of the peat mosses (Fig. 231) from which they take their name. These plants and the others which associ- ate with them are mostly hydrophytes, living usually with a considerable portion of the plant continually submerged in the bog water. The water of such bogs contains little mineral matter and only a very scanty supply of nitrogen, in the form of nitrates dissolved in it. The bog-plants, therefore, must either get on with an exceptionally small supply of nitrogen or they must get it from an unusual source. The peat mosses adopt the former alternative, while the sun dews (Fig. 238), the pitcher-plants (Fig. 237), and some other species adopt the latter and derive their nitrogen supply largely from insects which they catch, kill, and digest. 399. Arctic Vegetation. — The seed-plants of the Fic. 231. arctic flora are mostly perennials, never trees. Peat Moss. By the large bulk of the underground portion as compared with that of the part above ground, they are adapted to a climate in which they must lie dormant 828 FOUNDATIONS OF BOTANY for not less than nine months of the year. The flowers are often showy and appear very quickly after the brief summer begins. Mosses and lichens are abundant, — the latter of economical importance because they furnish a considerable part of the food of reindeer. : 400. Mountain or Alpine Vegetation. — In a general way the effect of ascending a mountain, so far as vegetation is Fic. 232.— A Plant of Arctic Willow. (About natural size.) concerned, is like that of traveling into colder regions. It was long ago suggested, in regard to Mount Ararat, that on ascending it one traversed first an Armenian, then a South European, then a French, then a Scandinavian, and finally an arctic flora. Up to a certain height, which varies in different latitudes, the slopes of mountains are very commonly forest-covered. The altitude up to which trees can grow (or as it is commonly called in this country: the “timber line”) is somewhat over twelve thousand feet BOTANICAL GEOGRAPHY 829 in the equatorial Andes and lessens in higher latitudes as one goes either way from the equator. In the White Mountains, for instance, the timber line only rises to about four thousand five hundred feet. The seed-plants of alpine regions in all parts of the earth have a peculiar and charac- teristic appearance. It is easiest’ to show how such plants differ from those of the same species as they look when Fic. 233. - = Trobe ¥ near the Timber Line’ on. the Slope of Pikes Peak, growing. in w ohdinary situations. by réference to the plants themselves or to good’ pictures of them (see. Fig. 235). The differences between-alpine and non-alpine plants of the same or closely related species nave been summed up as: follows : + “The alpine individuals have shorter stems, smaller leaves, more strongly déveloped roots, equally large or somewhat larger and usually somewhat more deeply colored flowers, and their whole structure is drought-loving (xerophilous).” 1By A. F. W. Schimper. 330 FOUNDATIONS OF BOTANY J, Lys Sm SSA ae, Se f a Vy Fs i fi att iit af f ase ob Pests das Nir os, 4 — a as ¢ sinh te ea ; eal a f=? = Fig. 234, — Decrease in Size of Trees at High Elevations (Canadian Rockies), Trees at great elevations become much gnarled and stunted, as their growth is necessarily very slow (Fig. 233). The gradual diminution of the height of the BOTANICAL GEOGRAPHY 38381 trees on ascending a mountain is well shown in Fig. 234. The treeless character of the mountain summit is also plain.} Recent experiments have shown that many ordinary plants promptly take on alpine characteristics when they are transferred to moderate heights on mountains. For instance, a rather DCB fs commonly cultii /W A : vated sunflower,? [ he A, ate when planted at a ; height of about six | thousand five hun- dred feet, instead _. of having a tall leafy stem pro- duces a rosette of very hairy leaves lying close to the ground, thus be- coming almost un- recognizable as a sunflower. The change was even greater than that (Both drawn to the same scale.) shown in the rock A, low ground form ; B, alpine form. rose (Fig. 235) cultivated by the same experimenter. The peculiarities of alpine plants appear to be due mainly to the intense light which they receive during the daytime, (Se 1 Part of the diminution is only apparent, — the effect of distance, — but the growth at the highest levels is often less than waist high. 2 Helianthus tuberosus, the so-called Jerusalem artichoke. 832 FOUNDATIONS OF BOTANY to the strongly drying character of the air in which they grow (due partly to its rarefaction), and to the low temper- ature which they must endure every night. 401. Aquatic Vegetation. — Plants which live wholly in water often need a less complicated system of organs than. land-plants. True roots may be dispensed with altogether, as in many seaweeds, in most fresh-water alge, and in some seed-plants. A few such plants have mere. hold- fasts that keep them from drifting with the waves or the current. Sometimes roots may, as in the duckweeds (Fig. 220), serve the purpose of a keel and keep the flat, expanded part of the plant from turning bottom up. The tissues that give strength to the stems and leaves of land-plants are not usually much developed in submerged aquatics, since the water supports:-the weight of such plants. In some alge, as the common rockweed or blad- der-wrack (Fig. 183), the weight of the plant is admi- rably buoyed up by large air-bladders. ‘Transpiration is done away with, and. whatever carbonic acid gas or oxygen is absorbed or given off passes directly through the cell- walls into the interiors- of the cells. Generally water- plants do not reach any great size, but some species are the longest: of known plants, Macrocystis, the great kelp of the Pacific Ocean, attaining, it is said, the length of a thousand feet or more. In spite of the moderate size of most alge the total bulk in the various oceans must be extremely large. The Sargasso Sea alone, in the Atlantic Ocean, reaches most of the way from the Bahamas to the Azores and extends over seventeen degrees of latitude. The whole area is occupied by a nearly compact mass of floating seaweed. BOTANICAL GEOGRAPHY 833 Besides the comparatively well-known and readily seen larger alge there is a great amount of vegetation floating in what is known as the plankton. This is a mass of microscopic animals and plants, found floating scum-like or submerged in fresh and in salt water and often accu- mulated in great quantities near shores, to which it is .swept by the action of the wind and waves and currents. Much of the plant life of the plankton, both of fresh and of salt water, often consists of the flinty-shelled one-celled microscopic algze known as diatoms (Fig. 176). 402. Botanical Geography of the United States. — All of the continuous territory of the United States 1 lies in the north temperate zone. There is material for a large vol- ume in the discussion of the distribution of plants over our territory in this continent alone, but it is possible to sum up a mere outline of the matter ina very few words. Excluding the floras of many single mountains and moun- tain ranges, the land surface of the country may for’ botan- ical purposes be divided into four great areas, as follows: 1. The Forest Region. — This occupies the eastern and, central portion of the United States. It is bounded on the west by an irregular line, most of which-lies to the eastward of the hundredth meridian. In_some places this forest boundary extends eastward across the Mississippi River, while in others it recedes from the river five hundred miles or more to the westward. 2. The Great Plains Region. — This extends westward from the region above named to the Rocky Mountain Plateau. 1 That is, not counting in Alaska, our west Indian possessions, the Sand- wich Islands, or the Philippines. 334 FOUNDATIONS OF BOTANY 8. The Pacific Highland Region. — This includes the Rocky Mountains, the Sierra Nevada, and the various plateaus between them. 4. The Pacific Slope.— This extends from the Cascade Range and the Sierra Nevada to the sea. 403. Characteristics of the Four Regions. — The forest region is mainly remarkable for its great variety of hard- wood trees, of which it contains a larger number of useful species than any equal area of the earth with a temperate climate. In the northeasterly portion and in much of the southerly portion there are extensive forests of the cone-bearing evergreens, such as pines, spruces, hemlocks, and cedars. The vegetation is in general such as thrives in medium conditions as regards heat and rainfall. The plains region is largely covered with grasses, many of them xerophytes. Some of the most characteristic plants associated with the grasses are Composite, such as sun- flowers, rosin-weeds (Silphiwm), cone-flowers, gum-weeds (Grindelia), and blazing-stars (Liatris). The Pacific highland region includes a very great vari- ety of plant societies, from the heavily wooded mountain slopes and valleys to high sterile plains which are almost deserts. Cone-bearing evergreen trees are very character- istic of the forests. Great numbers of alpine species of herbs and shrubs are found on the mountains at and above the timber line. In the alkali regions, where the soil is too full of mineral salts to permit ordinary plants to grow, many kinds of xerophytes, such as the salty sage (Atriplez) and the greasewood (Sarcobatus), occur. In the southern portion cactuses abound. Puate VIII. — Tree Belt along.a Stream, Nebraska BOTANICAL GEOGRAPHY 335 The Pacific Slope is characterized by cone-bearing ever- greens in great abundance in the mountains and along the foothills. Chief among these in point of size are the red- woods and the “big trees” (Sequoias) (Fig. 82). Oaks are represented by a good many species, several of them evergreen. There are many xeroplytes, some of them characteristic of alkali regions; and in Southern California, on account of the long dry season, plants with large roots or rootstocks and bulb-bearing plants (many: of them belonging to the lily family) are abundant. The tree yucca (Plate VII) is one of’the largest and most inter- esting xerophytic plants of North America. CHAPTER XXVI PARASITES, ENSLAVED PLANTS, MESSMATES, CARNIVOROUS PLANTS 404. Parasites. — A little was said in Chapter IV about parasitic plants, and the life history of one of them, the dodder, was briefly outlined,; another, the wheat rust, was discussed in Sects. 310-813. persistent. Corolla wheel-shaped, 5-lobed. Stamens 5, projecting, the filaments very short, the anthers long and meeting about the style. Ovary 2-celled; style slender. Fruit a many-seeded, juicy berry.* 1. S. Dulcamara, L. Bittersweet. Perennial. Stems rather shrubby, long, and climbing. Leaves heart-shaped, or some of them with irregular lobes, or ear-like leaflets at the base. Flowers blue or purple, somewhat cymose. Berries showy, of many shades of orange and red in the same cluster, according to their maturity. 2. S. nigrum, L. NigutsHapse. Annual; stem smooth, or downy with simple hairs, erect, diffusely branched; branches witig- angled, 1-3 ft. high. Leaves ovate, irregularly toothed or entire, somewhat inequilateral, petioled. Flowers in lateral, peduncled um- bels, small, white, drooping. Calyx-lobes obtuse; corolla 4—4 in. wide; filaments downy; berries globose, smooth, black when ripe. Common in cultivated fields and waste places.* 8. S. carolinense, L. Horse Nettie. Perennial; stem erect, branched, downy with star-shaped hairs, armed with straight, yellow prickles, 1-3 ft. high. Leaves ovate-oblong, deeply toothed or lobed, 200 FOUNDATIONS OF BOTANY acute at the apex, abruptly contracted to the short petiole, prickly on the veins. Racemes lateral, few-flowered; pedicels recurved in fruit. Calyx-lobes taper-pointed. Corolla deeply angular-lobed, blue or white; berry globose, smooth, yellow. A common weed.* 4. S. rostratum, Dunal. Sanp Bur, Burrato Bur. Annual; the whole plant beset with yellow prickles; stem erect, diffusely branched, 1-2 ft. high. Leaves broadly oval or ovate in outline, deeply pinnately lobed or parted, petioled, downy, with star-shaped hairs. Racemes few-flowered; pedicels erect in fruit. Calyx very prickly, becoming enlarged and enclosing the fruit. Corolla bright yellow, 5-emgled, about 1 in. broad. Introduced from the West, and becoming a troublesome weed in some places.* 5. S. tuberosum, L. IrisH Potato. Annual; stem diffusely branched, downy, underground branches numerous and tuber-bearing. Leaves irregularly pinnatifid and divided.’ Flowers in cymose clus- ters, white or purple, with prominent yellow anthers; pedicels jointed. Corolla 5-angled, 3-1 in. broad. Fruit a globose, greenish- yellow, many-seeded berry, about }$ in. indiameter. Cultivated from Chili.* Il. LYCOPERSICUM, Tourn. Annual ; stem diffusely branched. Leaves pinnately divided. Flowers in raceme-like clusters on peduncles opposite the leaves. Oalyx 5-many-parted, persistent. Corolla wheel- shaped, 5—6-parted. Stamens 5-6, inserted in the short tube of the corolla, filaments short, anthers elongated. Ovary 2-several-celled, style and stigma simple. Fruit a many- seeded berry.* 1. L. esculentum, Mill. Tomato. Stem diffusely branched, at length leaning over, furrowed and angled below, sticky-hairy, 3-5 ft. long. Leaves irregularly lobed and pinnatifid, petioled. Calyx- lobes linear, about as long as the yellow corolla. Fruit (in the wild state) globose or ovoid, red or yellow, 3-4 in. in diameter, but greatly enlarged in cultivation. Common in cultivation from tropical America.* IV. DATURA, L. Annual or perennial, strong-scented herbs; stems tall and branching. Leaves petioled, entire or lobéd. Flowers large, soli- tary in the forks of the bfanches. Calyx tubular, 5-toothed or lobed, the upper part deciduous and the lower persistent. Corolla funnel-form, 5-angled. Stamens 5, inserted in the DICOTYLEDONOUS PLANTS 201 corolla-tube. Ovary 2-celled or imperfectly 4-celled ; style filiform ; stigma 2-lobed. Fruit a spiny, 4-valved, many-seeded capsule.* 1. D. Stramonium, L. Jimson-weep. Annual; stem smooth, green, stout, forking above, 1-4 ft. high. Leaves ovate to oblong- ovate, acute at the apex, narrowed at the base, sinuate-toothed, petioled. Calyx 5-angled. Corolla white, about 4 in. long. Capsule ovoid, erect, 2 in. long. A common weed; poisonous. Introduced from Asia.* 2. D. Tatula, L. Taller, with a purple stem. Flowers rather later than No. 1; corolla violet-tinged. V. PETUNIA, Juss. Herbs; leaves alternate and entire. Divisions of the calyx oblong-spatulate. Corolla showy, spreading funnel-shaped, not perfectly regular. Stamens 5, somewhat unequal in length, inserted in the middle of the corolla-tube and not projecting beyond it. Capsule 2-celled, containing many very small seeds. 1. P. violacea, Lindl. Common Petunia. Stems rather weak and reclining. Leaves covered with clammy down. Corolla vary- ing from pale pink to bright purplish-red, often variegated, with a broad, inflated tube, which is hardly twice as long as the calyx. Cultivated annual from South America. 2. P. nyctaginiflora, Juss. Wouits Petunia. Leaves somewhat petioled. ‘Tube of corolla long and slender. Flowers white. Culti- vated from South America. This and the preceding species much mixed by hybridization. 89. SCROPHULARIACEA. Ficwort Famity. Mostly herbs, with irregular flowers. Calyx free from the ovary and persistent. Corolla 2-lipped or otherwise more or less irregular. Stamens usually 2 long and 2 short, or only 2 in all, inserted on the corolla-tube, often 1 or 3 of them imperfectly developed. FPistil consisting of a 2-celled and usually many-ovuled ovary, with a single style and an entire or 2-lobed stigma. 202 FOUNDATIONS OF BOTANY Corolla wheel-shaped, stamens 5. Verbascum, I. Corolla wheel-shaped or salver-shaped, nearly regular, stamens 2. Veronica, VI. Corolla 2-lipped, the mouth closed by a palate, tubular below, a spur at the base. Linaria, IT. Corolla 2-lipped, the mouth closed by a palate, tubular below, a short, broad pouch at the base. Antirrhinum, III. Corolla decidedly 2-lipped. Stamens with anthers 2. Gratiola, V. Stamens 4, with a fifth antherless filament. Pentstemon, IV. Stamens 4, the anther-cells unequal. Castilleia, VIT. Stamens 4, the anther-cells equal. Pedicularis, VIII. I. VERBASCUM, L. Biennial ; stem tall, erect. Leaves alternate. Flowers in spikes, racemes or panicles. Calyx deeply 5-cleft. Corolla wheel-shaped, 5-lobed, the lobes nearly equal. Stamens 5, unequal, declined, some or all of the filaments bearded. Style flattened at the apex. Fruit a globose capsule; seeds roughened.* 1. V. Blattaria, L. Motu Muturin. Stem erect, slender, sim- ple or sparingly branched, smooth below, downy above, 2-4 ft. high, Leaves oblong to lanceolate, acute at the apex, obtuse or truncate at the’ base, dentate to pinnately lobed, the lower petioled, the upper sessile and clasping. Raceme long and loose, glandular-downy, pedicels bracted. Corolla white or yellow, marked with brown on the back, about 1 in. wide. Filaments all bearded with purple hairs. .Capsule longer than the calyx. Common in fields and waste places ; introduced from Europe.* I. LINARIA, Tourn. Herbs, rarely shrubby. Lower leaves opposite, whorled or alternate. Flowers in bracted racemes or spikes or axillary and solitary. Calyx 5-parted. Corolla 2-lipped, the tube spurred. Stamens 4, with sometimes a rudiment of a fifth. Stigma notched or 2-lobed. Capsule ovoid or globose; cells -nearly equal, DICOTYLEDONOUS PLANTS 203 1. L. vulgaris, Miller. Butter-anp-raes, JacoB’s Lapp#ER, Witp Frax. A perennial, erect, smooth herb, with a bloom, stem 1-2 ft. high. Leaves linear or lanceolate, 1-3 in. long, often whorled. Racemes densely flowered. Sepals shorter than the spur. Corolla yellow, $-1 in. long; spur parallel to and as long as the tube ; throat closed by a palate-like fold. Common in dry fields and pastures and along roadsides; introduced from Europe. 2. L. canadensis, Dumont. Toap-rLax. Biennial; flowering stems erect, slender, rarely branched, smooth, 1-2 ft. high, sterile stems prostrate, with opposite or whorled leaves, 2-6 in. long. Leaves linear, entire, sessile. Racemes erect, slender; pedicels erect, as long as the calyx. Corolla small, blue and white, the spur thread-like, curved, longer than the pedicels. Capsule 2-valved, the valves 3-toothed. On dry or cultivated ground E. Il. ANTIRRHINUM, Tourn. Annual or perennial herbs. Leaves entire, rarely lobed, the lower ones opposite, the upper alternate. Flowers axillary and solitary or racemed and bracted. Calyx 65-parted. Corolla 2-lipped. The tube with a sac, the broad bearded palate closing the throat. Stamens 4. Stigma with 2 short lobes. Capsule 2-celled, the upper cell opening by 1 pore, the lower by 2. 1. A. majus, L. Snappracon. Perennial; stem erect, smooth below, glandular-downy above, 1-2 ft. high. Leaves linear to oblong-lanceolate, entire, smooth, sometimes fleshy, sessile or short- petioled. Flowers in a terminal raceme; pedicels short, stout, erect in fruit. Corolla 13-2 in. long, of many colors. Capsule oblique, the persistent base of the style bent forward. Common in gardens, cultivated from Europe, and often escaped.* IV. PENTSTEMON, Mitchell. Perennials, the stems branching from the base, unbranched above. Leaves opposite. Flowers usually showy in a termi- nal panicle. Calyx of 5 nearly distinct sepals. Corolla tubular, the tube wide above and narrowed below; 2-lipped. Stamens 4, 2 long and 2 short, with a fifth antherless filament as long as the others, its upper half bearded. Capsule ovoid, acute. 1. P. pubescens, Solander. Stem somewhat sticky-downy, 1-2 ft. high. Leaves varying from oblong to lanceolate, 2-4 in. long, 204 FOUNDATIONS OF BOTANY usually with small teeth. Flower-cluster narrow. Corolla dingy violet, purplish, or whitish, the tube not much widened above, its throat nearly closed by a hairy palate. Sterile filament much bearded. Dry hillsides or stony ground. 2. P. levigatus, Solander. Stem usually smooth except the flower-cluster, 2-4 ft. high. leaves shining, those of the stem ovate-lanceolate or broadly lanceolate, 2-5 in. long, with a somewhat heart-shaped clasping base. Flower-cluster broader than in No. 1. Corolla white or oftener purplish, suddenly widened above, the throat not closed. - Sterile filament slightly bearded toward the top. In rich soil. 3. P. barbatus, Nutt. Stems slender and rod-like, 3-4 ft. high. Leaves lanceolate, entire. Flower-cluster long and loosely flowered. Flowers showy, drooping. Corolla-tube slender, scarlet, somewhat bearded in the throat. Sterile filament beardless. Cultivated from Mexico. V. GRATIOLA, L. Low herbs growing in wet or damp ground. Leaves oppo- site, sessile. Flowers axillary and solitary, peduncled. Calyx 5-parted, usually with 2 bractlets at the base. Corolla some- what 2-lipped. Perfect stamens 2. Stigma enlarged or 2-lipped. Pod 4-valved, many-seeded. 1. G. virginiana, L. Stem cylindrical, 4-10 in. long, branching from the base. Leaves 3-14 in. long, varying from lance-oblong to spatulate. Corolla pale yellow, tinged with red. Common in muddy soil, along brooksides, etc. VI. VERONICA, Tourn. Herbs or shrubs. Lower leaves or all the leaves opposite, rarely whorled. Flowers in axillary or terminal racemes, rarely solitary. Calyx usually 4-parted. Corolla wheel- shaped or somewhat bell-shaped; limb usually 4-cleft, spread- ing, the side lobes commonly narrower. Stamens 2, inserted on the corolla-tube at the sides of the upper lobe, projecting. Stigma somewhat knobbed. Capsule generally flattened, often notched at the apex, 2-celled, few-many-seeded. 1. V. americana, Schweinitz. Brooxiime. A perennial smooth herb, somewhat prostrate below, but the upper parts of the stem erect, 8-15 in. high. Leaves 1-2 in, long, lance-ovate or oblong, DICOTYLEDONOUS PLANTS 205 serrate, short-petioled. Racemes 2-4 in. long, axillary and opposite. Corolla wheel-shaped, blue. Capsule swollen, roundish. Muddy soil about springs and brooks. : 2. V. officinalis, L. Common SprepweLt, Gypsy Weep. Perennial. Roughish-downy, with the prostrate stems spreading and rooting. Leaves wedge-oblong or nearly so, obtuse, serrate, somewhat petioled. Racemes dense, of many pale bluish flowers. Capsule rather large, inversely heart-shaped. and somewhat trian- gular. Dry hillsides, open woods and fields. 3. V. serpyllifolia, L. THyme-LEAVED SPEEPWELL. Perennial. Smooth or nearly so; branching and creeping below, but with nearly simple ascending shoots, 2-4 in. high. Leaves slightly crenate, the lowest ones petioled and roundish, those farther up ovate or oblong, the uppermost ones mere bracts. Raceme loosely flowered. Corolla nearly white or pale blue, beautifully striped with darker lines; cap- sule inversely heart-shaped, its width greater than its length. Damp grassy ground ; a common weed in lawns. 4, V. peregrina, L. Purstane Sprerpwrtit. A homely, rather fleshy, somewhat erect-branched annual weed, 4-9 in. high. Lowest leaves petioled, oblong, somewhat toothed, those above them sessile, the uppermost ones broadly linear and entire. Flowers solitary, inconspicuous, whitish, barely pediceled, appearing to spring from the axils of the small floral leaves. Corolla shorter than the calyx. Roundish, barely notched, many-seeded. Common in damp ground, in fields and gardens. Vl. CASTILLEIA, Mutis. Herbs parasitic on the roots of other plants. Leaves alter- nate; the floral ones usually colored at the tip and more showy than the flowers. Flowers yellow or purplish in terminal leafy spikes. Calyx tubular, flattened, 2-4-cleft. Corolla-tube included within the calyx; upper lip of the corolla very long, linear, arched, and enclosing the stamens, 2 of which are long and 2 short. Ovary many-ovuled. 1. C. coccinea, Sprengel. ScarteT Parnrep Cur, Parnt-BRusH, InpDIAN Pink, PRAIRIE Fire, WickaKEE. A hairy, simple-stemmed herb. Annual or biennial. Root-leaves clustered obovate or oblong. Stem-leaves cut; floral leaves 3-5 cleft and bright scarlet (occasion- ally yellow) toward the tips, as though dipped in a scarlet dye. Calyx nearly as long as the pale yellow corolla, 2-cleft. The spikes are often very broad, making this one of the most conspicuous of our native flowers. Damp, sandy ground, or on bluffs near streams; sometimes in marshes. 206 FOUNDATIONS OF BOTANY VOI. PEDICULARIS, Tourn. Perennial herbs, with the lower leaves pinnately cut and the floral ones reduced to bracts. Flowers spiked. Corolla markedly 2-lipped; the upper lip much flattened laterally and arched, the lower lip spreading, 3-lobed. Stamens 4, beneath the upper lip. Capsule 2-celled, tipped with an abrupt point, several-seeded. 1. P. canadensis, L. Common Lousewort. Hairy, with clus- tered simple stems, 1 ft. high or less. Leaves petioled, the lower- most ones pinnately parted, the others somewhat pinnately cut; spike short, closely flowered and leafy-bracted; calyx split down the front; corolla greenish-yellow and purplish, with its upper lip hood-like, curved under, and with 2 awl-like teeth near the end; capsule flat, broadly sword-shaped. Knolls and openings among thickets. 90. BIGNONIACEZ. Bicnonra FamIty. Trees or shrubs, often twining or climbing, rarely herbs. Leaves usually opposite, without stipules. Flowers showy, irregular. -Corolla tubular, with a widened throat and a 5-lobed limb. Stamens usually 2 long and 2 short, or only 2. Ovary free from the calyx, 2-celled or rarely i-celled, with many ovules. Fruit a capsule; seeds large, winged. I. BIGNONIA, Tourn. Woody vines. Leaves opposite, compound, usually ten- dril-bearing. Flowers large, in axillary clusters. Calyx cup-shaped, truncate, or undulate-toothed. Corolla spreading- tubular, somewhat 2-lipped, the lobes rounded. Stamens 4, 2 long and 2 short. Capsule linear, flattened parallel with the partition, the two valves separating from the partition at maturity. Seeds flat, broadly winged.* | 1. B. capreolata, L. Cross-vine. Stem climbing high, a trans- verse section of the older stems showing a conspicuous cross formed by the 4 medullary rays; branches smooth. Leaves evergreen, petioled ; leaflets 2, ovate, taper-pointed with a blunt apex, heart- shaped at the base, entire, stalked, upper leaflets transformed into DICOTYLEDONOUS PLANTS 207 branching tendrils. Flowers numerous, short-peduncled. Corolla 2 in. long, reddish-brown without, yellow within. Capsule 6 in. long, flat, the valves with a prominent central nerve. Seeds broadly winged on the sides, short-winged on the ends. Common in woods S.* I. TECOMA, Juss. Woody vines, climbing by aerial rootlets. Leaves com- pound, odd-pinnate. Flowers large, in terminal clusters. Calyx bell-shaped, unequally 5-toothed. Corolla funnel-form, enlarged above the calyx, 5-lobed, slightly 2-lipped. Stamens 4, 2 long and 2 short. Capsule slender, spindle-shaped, slightly compressed contrary to the partition, 2-valved, dehis- cent. Seeds winged.* 1. T. radicans, Juss. Trumpet FLowrer, TruMPET CREEPER. Stems climbing high by numerous rootlets, bark shreddy. Leaves deciduous, petioled; leaflets 9-11, ovate to ovate-lanceolate, serrate, . short-stalked, smooth or slightly downy. Flowers in short, terminal racemes or corymbs. Calyx tubular, 3 in. long. Corolla 2-3 in. long, scarlet without, yellow within, the lobes spreading. Capsule 5-6 in. long, curved, often persistent through the winter. Seeds broadly winged. On borders of fields and in woods S.; often cultivated.* Il. CATALPA, Scop., Walt. Small trees. Leaves large, opposite, simple, petioled, decid- uous. Flowers large and showy, in terminal panicles. Calyx irregularly 2-lipped. Corolla tubular-bell-shaped, oblique, 5-lobed, 2-lipped. Fertile stamens 2, sterile stamens 3, short. Fruit a linear, 2-valved, many-seeded capsule. Seeds winged.* 1. C. bignonioides, Walt. CatTatpa. A small tree with thin, rough, gray bark and light, soft, but exceedingly durable wood. Leaves long-petioled, heart-shaped, entire or palmately 3-lobed, taper- pointed at the apex, palmately veined, downy. Branches of the panicle in threes; flowers large, 1-14 in. long, white, variegated with yellow and purple. Corolla lobes undulate or crisped. Capsule very slender, 1 ft. or more in length, pendulous. Seeds with long, fringed wings. On margins of rivers and swamps S., often cultivated.* 2. C. speciosa, Warder. Cataxpa. A tall tree with very durable wood. Leaves large, heart-shaped, taper-pointed. Corolla about 2 in. long, almost white, but slightly spotted ; tube inversely conical ; 208 FOUNDATIONS OF BOTANY limb somewhat oblique, its lower lobe notched. Pod rather stout. Rich, damp woods, especially 8. W. ; often cultivated. 91. OROBANCHACEA. Broom-RaPE FAMILY. Leafless brownish root-parasites. Rootstock often tuberous, naked or scaly. Stem usually stout, solitary, scaly. Flowers spiked or racemed. Sepals 4-5, free from the ovary. Corolla hypogynous, irregular, the tube curved; the limb 2-lipped. Stamens 4, 2 long and 2 short, inserted on the corolla-tube ; anthers 2-celled, the cells spurred at the base. Ovary 1-celled, of 2 carpels, style simple, stigma 2-lobed; ovules many. Cap- sule 1-celled, 2-valved, few-many-seeded ; seeds very small. I. CONOPHOLIS, Wallroth. Stems often clustered, stout, covered with scales which overlap, the uppermost ones each with an axillary flower, thus forming a spike. Calyx irregularly 4-5 cleft, split down the lower side. Corolla swollen below, decidedly 2-lipped, the upper lip arched. Stamens projecting. 1. C. americana, Wallroth. Squaw-root, CANCER-ROOT. Stems 3-6 in. high, yellowish or yellowish-brown. Flowers numerous, in- conspicuous. Corolla dirty white or pale brown. In oak woods, not very common. I. APHYLLON, Mitchell. Brownish or whitish plants with naked scapes borne on scaly, mostly underground stems. Calyx regular, 5-cleft. Corolla 5-lobed, slightly irregular. Stamens not projecting from the corolla-tube. 1. Aphyllon uniflorum, Gray. ONE-FLOWERED CANCER-ROOT. Slightly covered with clammy down. Stems very short-branched, each with 1-3 1-flowered scapes 3-5 in. high. Calyx-lobes lance- awl-shaped, half as long as the corolla. Corolla yellowish-white, veiny, purple-tinged, palate with 2 yellow bearded ridges. Damp woods. 2. A. fasciculatum, Gray. Stem scaly, upright, 3-4 in. high above ground and generally longer than the numerous 1-flowered pedun- cles. Calyx-lobes short, triangular. Parasitic on wild species of Artemisia, etc., in sandy and loamy soil N. W. and W. DICOTYLEDONOUS PLANTS 209 92. LENTIBULARIACEH. Biapperwort FamIty. Seape-bearing herbs, chiefly aquatic or living in marshes. Leaves are often thread-like and floating, without stipules. Flowers irregular. Calyx free from the ovary, persistent. Corolla hypogynous, 2-lipped, the tube short, spurred at the base. Stamens 2, opposite the lateral sepals, hypogynous or inserted on the corolla-tube. Ovary free, 1-celled; style short, thick, stigma 2-lipped, ovules many. Capsule 2-valved or bursting irregularly, many-seeded. UTRICULARIA, L. Aquatic or terrestrial herbs, often floating and propagated by buds which break loose from the plant and sink to the bottom of the pond or stream during the winter. Leaves of the aquatic species floating, thread-like, furnished with little bladders in which animalcules are caught. Flowers often rather showy, solitary, spiked or racemed. Corolla with its throat nearly closed by the palate. Capsule globose, bursting sirregularly. 1. U. cornuta, Michx. Hornep BLappERWoRT. Stemless. Leaves linear and entire or none; air bladders few or none. Scape erect, stout, 2-5-flowered, 8-12 in. high. Flowers yellow, fragrant, 3 in. wide. Pedicel as ‘long as the calyx. Lips of the corolla obovate, unequal, the lower longer, abruptly pointed, the sides reflexed, as long as the horn-shaped, curved spur, throat bearded. Seeds minutely pitted. In swamps and muddy places.* 2. U. subulata, L. Smarty BLappERWworT. Scape thread-like, 2-6 in. high. Leaves few and awl-shaped or none; air bladders few or none. Racemes zigzag, 1-6-flowered ; pedicels much longer than the calyx. Corolla yellow, } in. wide, the lower lip 3-lobed, longer than the appressed, conical, green-pointed spur. Wet, sandy soil.* 3. U. inflata, Walt. SwoLLen BLapDERWORT. Perennial; stem very slender, floating. Leaves finely dissected, the lower ones scat- tered, the upper ones whorled; the petioles dilated upward and inflated, air bladders very numerous. are stout, 6-12 in. high, 3-10-flowered. Corolla yellow, about 2 in. wide, upper lip ovate, slightly lobed, lower lip 3-lobed, twice the length of the curved, emarginate spur. Fruit nodding. In ponds and still water.* 210 FOUNDATIONS OF BOTANY 4. U. vulgaris, L. Greater BLADDERWORT. Stems submerged, leafy, 1-3 ft. long. Leaves spreading, pinnately cut into very many thread-like segments which bear many bladders. Scapes 6-12 in. long, 5-12-flowered, pedicels bent down after flowering. Corolla 3-3 in. long, yellow, upper lip broad and short, palate prominent; spur conical, pressed close to the under lip. Ponds and slowly flowing streams. 93. ACANTHACE2. Acantuus FamiIty. Herbs or shrubs. Leaves opposite or whorled, without stipules. Flowers irregular, usually with large bracts. Calyx of 4 or 5 unequal segments which considerably overlap each other. Corolla 4-5-parted and usually more or less 2-lipped. Stamens usually 2 long and 2 short, sometimes only 2. Ovary free from the calyx. Fruit usually a. capsule. Seeds not winged. A large family, mostly tropical, with only a few insignificant wild species in the northern United States. I. RUELLIA, Plumier. Perennial herbs; stems swollen at the joints and often between them, somewhat 4-angled. Leaves sessile or short- petioled, mostly entire. Flowers axillary, solitary or clustered, showy, white, blue, or purple. Calyx 2-bracted, 5-parted, the divisions linear and awl-shaped. Corolla-tube slender, often much elongated, the limb spreading, nearly equally 5-lobed. Stamens 4, 2 long and 2 short, included or slightly projecting. Style slender. Capsule slender, narrowed below, 4—12-seeded.* 1. R. strepens, L. SmootH Ruetzira. Stem erect, slender, usually simple, smooth or hairy, 1-3 ft. high. Leaves ovate to oblong, acute at the apex, narrowed below into a short petiole. Flowers solitary or in small clusters, sessile or short-peduncled. Calyx-lobes shorter than the tube of the corolla, downy or fringed. Corolla blue, the tube 1}-2 in. long, the limb 1-14 in. wide. Cap- sule usually longer than the calyx, smooth, 8-12-seeded. The later flowers often without a corolla. On rich, dry soil.* : 2. R. ciliosa, Pursh. Harry Ruewiia. Stem erect, rather stout, often few-branched. above, covered with white hairs, 4-30 in. high. Leaves oblong to ovate, acute or obtuse at the apex, narrowed and DICOTYLEDONOUS PLANTS 211 mostly sessile at the base, hairy-fringed. Flowers pale blue, solitary or 2-3 together. Calyx-lobes bristle-shaped, half the length of the corolla-tube. Tube of the corolla 2 in. long. Capsule shorter than the calyx, smooth, 8-12-seeded. A very variable species, the flowers often without a corolla. In dry woods and fields S.* fl. DIANTHERA, Gronov. Perennial herbs; stem smooth. Leaves opposite, entire or toothed. Flowers axillary, solitary or clustered, irregular. Calyx 5-parted. Corolla 2-lipped, upper lip erect, concave, entire or notched, the lower prominently veined, spreading, 8-lobed. Stamens 2, inserted in the throat of: the corolla. Ovary 2-celled, 4-ovuled, style simple, acute. Capsule flat- tened, narrowed below into a little stalk.* 1. D. americana, L. Water WitLow. Stem erect, slender, 2-3 ft. high. Leaves lanceolate to linear-lanceolate, taper-pointed at the apex, narrowed below to the sessile or short-petioled base. Flowers bracted, in short spikes, on peduncles as long as the leaves. Corolla pale blue or purple, the tube as long as the lips, lower lip wrinkled. Capsule about the length of the calyx. In water 8.* 94, PLANTAGINACEA. PLantTain Famity. Annual or perennial scape-bearing herbs. Leaves usually all radical, with parallel ribs. Flowers small, green, usually spiked, regular and perfect (Fig. 21). Sepals 4, persistent. Corolla hypogynous, salver-shaped, thin and dry; lobes 4, spreading. Stamens 4, usually inserted on the corolla-tube, filaments thread-like, anthers large and versatile. Ovary free, usually 2-4-celled; style thread-like. Fruit a 1-4-celled, 1 or more seeded membranous capsule, which splits open transversely, the top coming off like a lid. PLANTAGO, L. Characteristics of the genus as given above for the family. 1. P. major, L. Pxranrain. Perennial, from a very short root- stock. Leaves ovate to oval, strongly 5-9-ribbed, acute or obtuse at 212 FOUNDATIONS OF BOTANY the apex, rounded at the base into a long, concave petiole, entire or toothed, smooth or slightly downy. Scape taller than the leaves, downy, spike densely flowered; bracts short, ovate. Flowers per- fect. Stamens 4, projecting. Capsule ovoid, about twice the length of the calyx. Common in dooryards.* 2. P. lanceolata, L. Rrise@rass. Biennial or perennial; soft- hairy or nearly smooth. Leaves numerous, lanceolate to elliptical, acute, long-petioled, strongly 8-5-ribbed, entire or toothed. Scapes much longer than the leaves, striate-angled, 1-2 ft. high, spike short and dense. Bracts and sepals ovate. Corolla smooth. Cap- sule longer than the calyx, 2-seeded. Introduced; common in meadows.* 8. P. aristata, Michx. LARGE-BRACTED PLAN- Tain. Annual. Leaves broadly linear, entire or sparingly and finely toothed, narrowed below into a margined petiole, smooth or silky-downy. Scape longer than the leaves, 6-10 in. high, spike dense. Bracts linear, 3-1 in. long. Stamens 4; capsule 2-seeded, longer than the calyx. Common on dry soil.* 4. P. heterophylla, Nutt. Mawny- SEEDED PLantTain. Annual. / Leaves linear, fleshy, entire, or with Fic. 21.—Flowers of Plantain a few spreading teeth, smooth or (Plantago), enlarged. slightly downy. Scapes slender, 3-6 A, earlier stage, pistil mature, sta- jn, high, spike very slender, many- mens not yet appearing outside flowered, the lower flowers often. the corolla. B, later stage, pistil scattered. Bracts ovate, longer than ern the sepals. Stamens 2. Capsule twice the length of the calyx, many-seeded. Common in cultivated ground, especially S.* 95. RUBIACEX. Mapper Famity. Herbs, shrubs, or trees. Leaves opposite and entire, with stipules between them, or appearing whorled since the stipules resemble the leaves. Flowers always perfect, frequently dimorphous (as in Houstonia, Mitchella, and Bouvardia). Calyx-tube adnate to the ovary; limb 3-6-toothed. Corolla regular, inserted on the calyx-tube, as many-lobed as the calyx. Stamens equal in number to the divisions of the corolla. Ovary 2 or more celled. A very large and important DICOTYLEDONOUS PLANTS 213 family, of which many of the important species, for instance, the coffee shrub aud the cinchona tree, are natives of warm or tropical climates. I. HOUSTONIA, L. Annual, biennial, or perennial herbs; stems erect or diffuse. Leaves entire, stipules often only a line connecting the bases of opposite leaves. Flowers small, solifary, or clustered. Calyx 4-toothed, persistent. Corolla wheel-shaped to funnel- form, 4-lobed. Stamens 4. Ovary 2-celled, style slender, stigmas 2. Fruit a 2-celled, few-many-seeded capsule, open- ing at the apex, free from the calyx.* 1. H. cerulea, L. Buvets, Innocence, QuakeR Lapiss, Evye- BRIGHT. Perennial, from very slender rootstocks; stems tufted, erect, smooth, forking, 3-6 in. high. Leaves sessile, often hairy- fringed, the lower spatulate, the upper lanceolate. Flowers solitary, on slender axillary peduncles. Calyx small. Corolla salver-form, blue or white, yellow in the throat, smooth, of two forms, the stamens projecting and the style short in one form, while in the other the stamens are short and the style projecting. Capsule laterally com- pressed, 2-lobed, shorter than the calyx. Common on open ground.* 2. H. patens, Ell. Smaty Biuets. Annual. Stem erect, branched at the base, forking above, smooth, 2-4 in. high. Lower leaves oval to ovate, petioled, the upper narrower and sessile. Flowers solitary, on slender, axillary peduncles, blue or white. Calyx small. Lobes of the corolla about as long as the tube ; stamens and style project- ing or included. Capsule compressed, as long as the calyx. Com- mon on dry, open ground.* 3. H. purpurea, L. Large Buiuets. Perennial; stem stout, erect, simple or branched, smooth or downy, 4-angled, 6-12 in. high. Leaves ovate to ovate-lanceolate, sessile or short-petioled, 3—5-nerved, often hairy-fringed on the margins. Flowers in terminal cymes, purple to nearly white. Corolla funnel-form; the tube longer than the limb, hairy within. Stamens and style projecting or included. Capsule compressed-globose, much shorter than the calyx. In dry, open woods.* : Var. longifolia, Gray. LoneG-Leavep Biuets. Perennial. Stem erect, branched, smooth, 4-angled, 8-12 in. high. Leaves sessile, the lower oblanceolate or spatulate, the upper linear, 1-nerved. Corymbs terminal, few-flowered. Corolla light purple to white, the lobes much shorter than the tube. Capsule compressed-globose, nearly as long as the calyx. In dry, open woods.* 214 FOUNDATIONS OF BOTANY Il. BOUVARDIA, Salisb. Smooth perennials. Leaves lanceolate, thickish. Calyx 4-lobed, the divisions slender. Corolla with a long and nar- row or rather trumpet-shaped tube and spreading 4-lobed limb. Anthers 4, inserted in the throat of the corolla, almost sessile. Stigmas 2, flat... Capsule globular, 2-celled, many-seeded. Flowers dimorphous. 1. B. triphylla, Salisb. THreE-LEAVED Bouvarpia. Somewhat shrubby. Leaves nearly smooth, ovate or oblong-ovate, the lower ones in threes, the upper ones sometimes in pairs. Corolla scarlet and slightly downy outside. 2. B. leiantha, Benth. Downy-LEaAvep Bovuvarpia. Leaves rather downy. Corolla deep scarlet, smooth outside. Both species cultivated from Mexico; in greenhouses. Il. MITCHELLA, L. A pretty trailing evergreen herb. Leaves roundish-ovate, petioled. Flowers fragrant, white or pinkish, dimorphous, growing in pairs, joined by their ovaries. Calyx 4-toothed. Corolla funnel-shaped, with the lobes bearded within. Sta- mens 4, short. Style 1, stigmas 4, slender. Fruit double, composed. of the united ovaries, really a stone-fruit containing 8 seed-like bony nutlets, ripening into tasteless scarlet berries which cling to the plant through the winter. 1. M. repens, L. Partripce Berry, Squaw Vinr, Two-EyYE Berry. Common in dry woods, especially under evergreen conif- erous trees. Iv. GALIUM, L. Annual or perennial herbs; stems slender, 4-angled. Leaves appearing whorled. Flowers small, in axillary or terminal cymes or panicles, perfect or rarely dicecious. Calyx-tube short, the teeth minute or wanting. Corolla wheel-shaped, 8-4-lobed. Stamens 3-4, short. Ovary 2-celled, styles 2, short, united below. Fruit 2, united, sometimes fleshy, 1-seeded carpels which do not split open.* 1. G. Aparine, L. Goosrcrass. Annual; stem weak, decum- bent, sharply 4-angled and with backward pointing prickly hairs, DICOTYLEDONOUS PLANTS 215 widely branched, 24 ft. long. Leaves 6-8 in a whorl, oblanceolate, prickly-hairy on the margins and midrib. Peduneles axillary, longer than the leaves, 1-3-flowered; flowers white. Fruiting pedi- cels erect; fruit dry, covered with hooked bristles. In waste places. ; 2. G. circezans, Michx. Witp Licorics. Perennial; stems several, erect, smooth or downy, 12-18 in. high. Leaves 4 in a whorl, oval to ovate, obtuse at the apex, strongly 3-nerved, downy. Cymes long-peduncled, repeatedly branched. Flowers ne“rly sessile, greenish-purple; pedicels at length recurved. Fruit with hooked bristles. In dry, open woods S. Easily recognized by the sweet, licorice-like taste of the leaves.* 3. G. hispidulum, Michx. Brpstraw. Perennial, from yellow roots; stems diffusely branched, smooth or slightly roughened, downy at the joints, erect or decumbent, 1-2 ft. long. Leaves 4 in a whorl, narrowly oval, acute, rough on the margins and mid-vein. Peduncles 1-8-flowered ; flowers white. Pedicels becoming reflexed ; fruit a bluish-black, roughened berry. On dry, sandy soil.* 4. G. triflorum, Michx. Perennial; stems reclining or prostrate, angles rough-bristly. Leaves mostly in sixes, lance-oblong, mucro- nate. Flowers usually in threes, on slender peduncles. Woodlands, especially N. 96. CAPRIFOLIACEZ. Honrysuckie FAMILy. Mostly shrubs. Leaves opposite, without true stipules. Flowers often irregular. Calyx-tube adnate to the ovary. Corolla tubular or wheel-shaped. Stamens usually as many ‘as the corolla-lobes and inserted on the corolla-tube. Fruit a berry, stone-fruit, or capsule. I. SAMBUCUS, Tourn. Shrubs with odd-pinnate leaves. Calyx-limb minute or wanting. Flowers very many, small, white, in compound cymes. Corolla with a small, somewhat urn-shaped tube and a flattish, spreading, 5-cleft limb. Stamens 5. Stigmas 3, sessile. Fruit a globular, pulpy stone-fruit, 3-seeded, appear- ing like a berry. e 1. S. canadensis, L. Common Exper. Stems 5-10 ft. high, with a thin cylinder of wood surrounding abundant white pith. 216 FOUNDATIONS OF BOTANY Leaflets 5-11, oblong, taper-pointed, smooth. Cymes flat and often very large. Fruit purplish-black, insipid or almost nauseous, but somewhat used in cookery. 2. S. racemosa, L. Rep-serriep ExLpEer. More woody, with brown pith. Leaflets fewer, downy beneath, especially when young. Cymes panicled and somewhat pyramidal. Fruit scarlet. Il. VIBURNUM, L. Shrubs or small trees. Leaves simple, entire, dentate or lobed, with or without stipules. Flowers small, white, in terminal cymes, the outer flowers of the cyme sometimes greatly enlarged and sterile. Calyx-tube very small, 5-toothed. Corolla wheel-shaped or bell-shaped, 5-lobed. Stamens 5, in- serted in the tube of the corolla. Ovary 1-3-celled, 1-3- ovuled, but only 1 ovule maturing; style short, 3-lobed. Fruit a 1-seeded stone-fruit.* A. Flowers around the margin of the cyme without stamens or pistils, large and showy. 1. V. lantanoides, Michx. Hoxsaie-BusnH, WITCH-HOBBLE. A shrub about 5 ft. high, with the branches reclining and often root- ing and forming loops (whence the popular names). Leaves very large, roundish, abruptly taper-pointed, serrate, with a rusty down on the petioles and veinlets. Cymes very broad and showy. Fruit red, not eatable. 2. V. Opulus, L. Cranperry Tree, Hicu-push CRANBERRY. A handsome, upright shrub. Leaves 3—5-ribbed and 3-lobed. Fruit bright red, juicy, very acid, and used as a substitute for cranberries. Common N. The form known as * Snowball” with all the flowers showy and sterile is cultivated from Europe. B. Flowers all small and perfect. 3. V. acerifolium, L. Mapie-Leavep Arrowwoop. A slender shrub 3-6 ft. high. Leaves broadly ovate to heart-shaped, palmately veined and 3-lobed, serrate or nearly entire, petioled, downy, becom- ing smooth above. Cymes peduncled, about 7-rayed, 2~3 in. wide; sterile flowers none. Fruit oval, black, stone flat, 2-ridged on the edges. In dry, open woods.* DICOTYLEDONOUS PLANTS 217 4. V. dentatum, L. Arrowwoopv. A shrub 8-15 ft. high. Leaves broadly ovate to oval, acute at the apex, rounded or heart- shaped at the base, coarsely dentate, smooth above, hairy in the axils of the veins beneath, short-petioled. Cymes long-peduncled, T-rayed, 2-3 in. wide; sterile flowers none. Calyx smooth. Fruit globose, dark blue, stone compressed, grooved on one side. In rich, damp soil.* 5. V. nudum, L. Wirtue-rop. A shrub 8-12 ft. high. Leaves ovate to lanceolate, entire or slightly toothed, acute at both ends, thick, smooth above, the veins prominent beneath ; petiole short. Cymes short-peduncled, 5-rayed ; sterile flowers none. Fruit ovoid, blue. Common in swamps.* 6. V. prunifolium, L. Brack Haw. A small tree, 15-20 ft. high. Leaves oval to ovate, acute or obtuse at each end, finely and sharply serrate, smooth and shining above, often slightly downy beneath; petioles dilated and rusty-downy. Cymes sessile, large, 4-5-rayed; sterile flowers none. Fruit oval, bluish-black, eatable. - In rich, moist woods.* III. SYMPHORICARPOS, Dill. Shrubs. Leaves short-petioled, deciduous. Flowers in axillary clusters. Calyx-tube globose, 4-5-toothed. Corolla bell-shaped, 4—5-lobed, sometimes knobbed at the base, smooth or hairy within. Stamens 4-5. Ovary 4-celled, 2 of the cells with a single fertile ovule in each, the other cells with several abortive ovules; style slender, stigma knobbed or 2-lobed. Fruit a 4-celled, 2-seeded berry.* 1. S. racemosus, Michx. SnowBerry. An ornamental shrub, 2-8 ft. high. Flowers in loose terminal racemes, which are often leafy. Corolla bell-shaped, much bearded inside, pinkish-white. Stamens and style not projecting. Berries rather large, snow-white, remaining long on the branches. Rocky banks, often cultivated. IV. LINNAA, Gronov. A very small, slender, creeping evergreen shrub; branches ‘inclined, ending in a slender, erect, 2-flowered peduncle. Leaves opposite, without stipules. Flowers nodding, on slen- ‘der pedicels, with 2 bractlets. Calyx-tube ovoid ; limb 5-lobed. Corolla nearly bell-shaped, 5-lobed. Stamens 4, inserted near the base of the corolla, 2 of them longer than the other 2 218 FOUNDATIONS OF BOTANY Ovary 3-celled; style thread-like, stigma knobbed; ovules many in 1 cell, solitary in the 2 others. Fruit nearly globose, 1-seeded. 1. L. borealis, L. Twin-rtower. A beautiful, delicate plant. Corolla pale pink, very fragrant. Moist woods, in. moss, and cold bogs N. Vv. TRIOSTEUM, L. Coarse, hairy, perennial herbs. Leaves large, those of each pair somewhat joined at the base, so that the stem appears to rise through them. Calyx-tube ovoid; divisions of the limb leaf-like, lance-linear, persistent. Corolla knobbed at the base, nearly equally 5-lobed. Ovary usually 3-celled, ripening into a stone-fruit with 3 nutlets. 1. T. perfoliatum, L. TinKER-wEED, WILD CorFresr, FEVER- worT, Horse-GENTIAN. Stem unbranched, soft-hairy, 2-4 ft. high. Leaves spatulate-ovate, abruptly narrowed at the base, 4-7 in. long and 2-4 in. wide, bordered with a fringe of hairs. Flowers dark brownish-purple. Corolla about 1 in. long, sticky-downy. Fruit ellipsoidal, orange-colored when ripe. Common along fence-rows and in rocky woods. VI. LONICERA, L. Shrubs or woody vines. Leaves simple, usually entire, those of a pair often appearing as if joined together at the base, so that the stem seems to rise through them. Calyx- tube ovoid, 5-toothed. Corolla tubular to bell-shaped, often knobbed at the base or 2-lipped. Stamens 5. Ovary 2-8- celled, ovules several in each cell; style slender, stigma knobbed. Fruit a 1-3-celled, 1-few-seeded berry.* A. Stems twining. 1. L. Sullivantii, Gray. YrLLow Honeysuckite. Stem some- what twining. Leaves oval to obovate, obtuse, entire, green above, with a bloom beneath, the lower short-petioled, the upper sessile or joined at the base. Flowers in crowded, terminal whorls, bright yellow, fragrant. Corolla-tube slender, 1-14 in. long, bilabiate,- 4.lobed, pubescent within. Stamens and style projecting. On river banks and hillsides; often cultivated.* DICOTYLEDONOUS PLANTS 219 2, L. sempervirens, L. Corat Honrysuckir, Trumpet Honey- SUCKLE. Stem twining high. Leaves evergreen (in the South), oval to oblong, obtuse. entire, smooth above, pale and often downy beneath, the lower petioled, the upper pair nearly semi-orbicular and joined at the base. Flowering spikes terminal, bearing several whorls. Corolla about 2 in. long, slender, smooth, the limb short, nearly equally 5-lobed, scarlet without, bright yellow within. Sta- mens slightly projecting; fruit red. On low ground; often culti- vated.* 3. L. japonica, Thunb. Jaran Honrysuckir. Stem twining high; young branches downy. Leaves ovate to oblong, entire, smooth above, pale and downy beneath, all short-petioled ; peduncles axillary, 2-bracted, 2-flowered; flowers white or pink, fading to yel- low, 2-lipped, the lips nearly as long as the downy tube. Stamens and style projecting. Fruit black. Introduced from Japan; com- mon in cultivation.* 4, L. Caprifolium, L. Evropran Honeysuckxite. A moder- ately high-climbing shrub. Leaves smooth and deciduous, several of the upper pairs united at their bases to form a flattish disk or somewhat cup-shaped leaf. Flowers in a single terminal whorl, very sweet-scented. Corolla whitish, red, or yellow, 2-lipped, with the lips recurved. Cultivated from Europe. B. More or less upright bushes, not climbing. 5. L. tatarica, L. TartarraN Honeysuckis. A_ branching shrub, 5-8 ft. high. Leaves oval or ovate, heart-shaped, shining. ‘Flowers many, showy, rose-colored. Fruit consisting of 2 red berries; somewhat united below at maturity. Cultivated from Asia. 6. L. ciliata, Muhl. Earty Fry Honeysuckte. A straggling bush, 3-5 ft. high. Leaves ovate or oval, slightly heart-shaped, thin, at first downy beneath. Flowers straw-yellow, on short, slender peduncles. Corolla-lobes nearly equal; tube pouched at the base. Fruit, 2 separate red berries. — VII. DIERVILLA, Tourn. Low, upright shrubs. Leaves taper-pointed, serrate. Flowers in loose terminal or axillary clusters or cymes. Calyx with a limb of 5 linear divisions. Corolla funnel-shaped, almost regularly 5-lobed. Stamens 5. Ovary slender, 2-celled, ripen- ing into a 2-valved, many-seeded pod. 220 FOUNDATIONS OF BOTANY 1. D. trifida, Moench. Common Busn Honrysuckie. Bushy, 1-4 ft. high. Leaves ovate or oblong-ovate, petioled. Peduncles . 1-8-flowered. Pods tapering to a slender point. Rocks, espe- . cially N: 2. D. japonica, Thunb. Wererna. A stout, branching shrub, 3-6 ft. high. Leaves broadly oval, acute at the apex, rounded at the base, coarsely serrate, rough above, downy beneath, short-peti- oled. Flowers spreading, funnel-form, rose-color, 1-1} in. long. Calyx-lobes deciduous. Corolla downy without, the lobes spreading. Capsule oblong or spindle-shaped. Seeds with netted wings. Intro- duced from Japan ; common in cultivation.* 97. VALERIANACEA. Vaverian Famity. Herbs, rarely shrubs. Leaves opposite, without stipules. Flowers small, usually irregular, in forking cymes. Calyx- tube adnate to the ovary. Corolla funnel-shaped, the base often with a sac or spur. Stamens 1-3 or 5, inserted at the base of the corolla-tube; filaments slender, anthers versatile. Ovary cells 3, two of them not ovule-bearing, the third with a single ovule hanging from the top; style thread-like, stigma blunt or 2-8-lobed. Fruit small, not splitting open. I. VALERIANA, L. Perennial, rarely annual, herbs. Root-leaves crowded; stem-leaves opposite or whorled, entire or pinnately cut. Flowers in corymbed, headed, or panicled cymes. -Limb of the calyx consisting of several plumy bristles. Lobes of the corolla 5 or rarely 3-4, unequal. Stamens 3. Stigma knobbed. Fruit flattened, ribbed, 1-celled, 1-seeded. 1. V. edulis, Nutt. An upright, straight-stemmed plant, 1-4 ft. high. Leaves all thickish and closely fringed with short hairs; root-leaves linear-spatulate or lanceolate-spatulate, entire; stem-leaves pinnately parted, the 3-7 divisions long and narrow. Flowers almost dicecious, in a long, interrupted panicle. Corolla whitish. Root long and stout, eaten by Indians. Low ground and wet prairies, especially N. W. 2. V. officinalis, L. Garpgen VALERIAN. Plant smooth or hairy below, strong-smelling. Rootstock short, eaves all pinnate ; root- DICOTYLEDONOUS PLANTS 221 leaves long-petioled, soon withering; stem-leaves 2-5 in. long, sessile, the leaflets lanceolate, entire or serrate. Corolla pale pink. Rootstocks strong-scented, used in medicine. Cultivated from Europe. I. VALERIANELLA, Tourn. Annual herbs; stem forking regularly. Leaves opposite, entire or dentate. Flowers in crowded, terminal, bracted cymes. Calyx-limb toothed or wanting. Corolla white or purplish, funnel-form, 5-lobed. Stamens 3. Style 3-lobed. Fruit 3-celled, 1-seeded.* 1. V. olitoria, Poll, Lams Lretrucr. Stem erect, smooth, or downy at the nodes, many times forked, 9-12 in. high. Basal leaves tufted, spatulate to obovate, entire, the upper lanceolate, dentate, sessile. Cymes short-peduncled, bracts linear. Flowers pale blue. Fruit compressed, oblique. On rich soil in waste places.* 2. V. radiata, Dufr. Corn Satap. Stem erect, smooth above, downy below, 2-4 times forked, 8-12 in. high. Lower leaves spatu- late, entire, the upper lanceolate, clasping at the base, dentate. Cymes compact; bracts lanceolate. Flowers white. Fruit ovoid, downy, furrowed. On damp soil.* 98. CUCURBITACEZ. Gourp Famiry. Somewhat succulent, tendril-bearing, prostrate or climbing, herbaceous plants. Leaves alternate, with stipules. Flowers dicecious or moneecious, often gamopetalous. Calyx-tube ad- nate to the ovary; calyx-liumb (if present) 5-lobed. Corolla. usually 5-lobed and with its tube more or less united with the calyx-tube. Stamens perigynous or borne upon the corolla, the anthers usually joined in long, serpentine ridges. Ovary 8-celled; stigmas 2 or’ 3. Fruit generally a pepo (like the melon, squash, and pumpkin), but sometimes dry. Seeds commonly large and flat. A large family, mostly of tropical plants, many with eatable fruit, but some species poisonous. 222 FOUNDATIONS OF BOTANY I. CUCURBITA, L. Annual or perennial herbs; stem trailing or climbing, 2-20 ft. long. Leaves angular-lobed; tendrils branching. Flowers moneecious, solitary or in small clusters. Calyx 5-toothed, the limb deciduous. Corolla bell-shaped, 5-lobed. Staminate flowers with 3'stamens and no pistil; pistillate flowers with 1 pistil and 3 imperfect stamens. Style short; stigmas 3-5, each 2-lobed. Fruit 1-celled, with numerous seeds on the 3 parietal placente.* 1. C. Melopepo, L. Summer Squasu. Stem rough-hairy, angled, 2-5 ft. long. Leaves broadly heart-shaped, angularly 3-5-lobed, rough. Flowers yellow, short-peduncled. Fruit roundish, longitudi- nally compressed, the margin smooth, wavy, or tubercular. Common in cultivation.* : 2. C. verrucosa, L. Crooxneck Squasu. Stem .rough-hairy, angled and striate, 5-10 ft. long. Leaves cordate, deeply 5-lobed, very rough, long-petioled. Flowers light yellow, long-peduncled. Fruit clavate, the base often slender and curved, smooth or tubercu- late, very variable. Common in cultivation.* II. CUCUMIS, L. Annual herbs; stems trailing, usually shorter and more slender than in the preceding genus. Tendrils not forked. Leaves varying from entire or nearly so to deeply cut. Sterile flowers in clusters, fertile ones solitary in the leaf-axils. Corolla of 5 acute petals, which are but little joined at the base. Stamens not evidently united. Style short; stigmas 3, each 2-lobed. Fruit rather long. Seeds not large, lance- oblong, not margined. 1. C. sativus, L. CucumBer. Leaves somewhat lobed, the middle lobe largest. Fruit more or less eovered when young with rather brittle, blackish prickles, which fall off as it ripens. Culti- vated from 8. Asia. [Other varieties of the genus Cucumis are the muskmelon, cantaloupe, and nutmeg melon. Other commonly cultivated genera are Citrullus, the watermelon, and Lagenaria, the bottle-gourd. Two wild genera, Echinocystis, the wild cucumber, and Sicyos, the star cucumber, which blossom through the summer and autumn, are common in the Northern States and the Middle ‘West. ] DICOTYLEDONOUS PLANTS 223 99, CAMPANULACEZ. CampanuLa FamIy. Herbs, with milky juice. Leaves alternate, without stipules. Flowers regular, not clustered. Calyx 5-lobed, adnate to the ovary. Corolla regular, bell-shaped, 5-lobed. Stamens 5, usually free from the corolla and not coherent. Style 1, usually hairy above; stigmas 2 or more. Fruit a capsule, 2-or more celled, many-seeded. I. CAMPANULA, Tourn. Annual, biennial, or perennial herbs. Fiowers solitary, racemed or spiked, regular, blue or white. Calyx 5-lobed or parted. Corolla wheel-shaped to bell-shaped, 5-lobed. Stamens 5, free from the corolla, distinct, filaments dilated at the base. Ovary 3—5-celled, many-ovuled; style 3-parted. Capsule short, bearing the persistent calyx-lobes at its apex, many-seeded, splitting open on the sides.* 1. C. rotundifolia, L. Harrsexy. A slender, smooth, branching perennial, 5-12 in. high. Root-leaves broadly ovate-heart-shaped, generally somewhat crenate, soon withering. Stem-leaves varying from linear to narrowly lanceolate, entire. Pedicels slender, flowers solitary or somewhat racemed, the buds erect but the fully opened flower drooping. Calyx.teeth erect, awl-shaped. Corolla bell-shaped, 4-1 in. long, its lobes short and recurved. Rocky hillsides, espe- cially N. 2. C. aparinoides, Pursh. Marsn Breri-rtrower. Stem angular, unbranched, slender, weak and leaning on the grass among which it usually grows, the angles clothed with minute, backward-pointing prickles. Leaves lance-linear, nearly entire. Flowers terminal, about 4 in. long, white. Corolla bell-shaped. Wet meadows, in tall grass. t. SPECULARIA, Heister. Annual; stems slender, angled. Leaves entire or toothed. Flowers axillary, regular, solitary or in small clusters, sessile, bracted. Calyx-tube slender, 3-5-parted. Corolla wheel- shaped, 5-lobed. Stamens with the filaments flattened and shorter than the anthers. Ovary 3-celled, many-ovuled ; stigmas 3. Fruit a prismatic, 3-celled, many-seeded capsule.* 224 FOUNDATIONS OF BOTANY 1. S. perfoliata, A. DC. Sprcutaria. Stem erect, simple or branched from the base, angles roughened, 10-20 in. high. Leaves ovate to lanceolate, acute at the apex, sessile, crenate or entire, the upper bract-like. Flowers solitary or in pairs. Corolla blue, often wanting. Capsule cylindrical, smaller above. In waste places.* 100. COMPOSITZ2. Composite Famity. Flowers in a dense head, on a common receptacle, sur- rounded by an involucre composed of many bracts (Fig. 22), Fia. 22,— Flower-cluster of Bachelor’s Button (Centawrea Cyanus). DICOTYLEDONOUS PLANTS 225 with usually 5 stamens inserted on the corolla, the anthers united into a tube which surrounds the style (Fig. 23, V). Calyx with its tube adnate to the ovary, the limb sometimes wanting, when present taking the form of scales, bristles, etc., known as pappus (Fig. 24, II, III). Corolla either strap- shaped (Fig. 25, r) or tubular (Fig. 23, V), in the former case I Il Ul Fia. 23. —Bachelor’s Button. I, vertical section of the receptacle; II, style and forked stigma (magnified) ; IH, corolla, united anthers and stigma (magnified) ; 1V, pistil (magnified) ; pap, pappus; ak,akene; V, tubular flower cut vertically (magnified), showing anther-tube, traversed by the style ; /, lobe of corolla. often 5-toothed, in the latter usually 5-lobed. Style 2-cleft above. Fruit an akene, often provided with means of trans- portation (Part II, Ch. XXIX). The largest family of flowering plants and among the most specialized for insect pollination. The genera of the northern United States are divided into two suborders: I. Tusutirior#, corolla of the perfect flowers tubular and 5-lobed ; IJ. Ligur1rLoRr2, corollas all strap-shaped and flowers all perfect. 226 FOUNDATIONS OF BOTANY Ill Fic. 24,—Bachelor’s Button. I, a tubular flower (magnified); anth, the united anthers ; I, fruit (magnified) ; III, fruit, vertical section (magnified); IV, a neutral ray-flower ;1 V, ring of anthers. Fic. 25.— Flower-cluster of Yarrow (Achillea Millefolium), enlarged. A, head seen from above ; B, longitudinal section ; re, receptacle ; ch, chaff ; i, involucre; r, ray-flowers ; d, disk-flowers ; c, corolla; s, stigma. 1 This is not precisely homologous with the ray-flowers of Helianthus and most rayed Compositz, but is an enlarged and conspicuous tubular flower. DICOTYLEDONOUS PLANTS 227 I. TUBULIFLORZ. Aj} Corollas some or all of them tubular. Rays white, pink, or purplish. Rays many; akenes flat; pappus wanting; low herbs. Bellis, I. Rays many; akenes cylindrical or winged, grooved; pappus wanting ; tall herbs or shrubby. Chrysanthemum, VIII. Rays many; akenes flat; pappus of an outer row of minute scales and an inner row of delicate bristles. Erigeron, II. Rays many; akenes cylindrical or ribbed; pappus wanting ; strong-scented branching herbs. Anthemis, VI. Rays few. Achillea, VII. Rays yellow. Disk purplish-brown. Rudbeckia, IV. Disk yellow. Involucre of 2 rows of bracts, the outer rather leaf-like. Coreopsis, ITT. Involucre of reflexed scales; pappus of 5-8 scales. Helenium, V. Involucre of erect scales ; pappus of abundant soft hairs. : Senecio, IX. Rays none, but the marginal flowers sterile and their tubular corollas partly flattened like rays (Fig. 24). Centaurea, X. Rays none and marginal flowers like the others; scales of the involucre overlapping in many rows, prickly-pointed. Cirsium, XI. B. Coroillas all strap-shaped. Corollas blue (rarely pinkish); akenes not beaked. Cichorium, XIII. Corollas blue; akenes beaked. Lactuca, XVIII. 1 The characters in this key are not necessarily true of all species in the genera referred to, but only of those described below. 228 FOUNDATIONS OF BOTANY Corollas yellow. Akenes truncate; pappus double, of chaff and bristles. Krigia, XII. Akenes columnar; pappus of tawny, rough bristles ; stem scape-like. Hieracium, XIV. Akenes spindle-shaped, not beaked; pappus of plumed bristles. Leontodon, XV. Akenes ovoid to spindle-shaped, long-beaked; pappus white, soft, and abundant. Taraxacum, XVI. Akenes nearly as in XVI; pappus tawny. Pyrrhopappus, XVII. Akenes flattened, beaked ; pappus soft, white, the hairs soon falling off separately ; leafy-stemmed herbs. Lactuca, XVITI. Akenes flattened, not beaked ; pappus abundant, soft, white ; leafy-stemmed, spiny-leaved herbs. Sonchus, XTX. I. BELLIS, L. Small herbs. Leaves usually all radical, petioled. Heads solitary, disk yellow, ray-flowers white or pink; involucre bell-shaped, bracts in 1 or 2 rows, green; receptacle conical. Ray-flowers many, in a single row, pistillate. Disk-flowers tubular, perfect, 4-5-toothed; forks of the style short, thick, tipped by roughened cones. Fruit flattened, obovate; pappus wanting. 1. B. integrifolia, Michx. AmErican Daisy. A branching annual or biennial herb, 4-12 in. high. Upper leaves lanceolate or oblong, the lower ones obovate-spatulate. Heads borne on slender peduncles; rays violet-purple. Prairies, especially S.W. 2. B. perennis, L. Enezuisa Daisy, Scorcu Daisy. A stem- less perennial. Leaves obovate-spatulate, smooth or hairy. Heads 3-1 in. in diameter, very pretty, the rays delicate. Cultivated from Europe. Il. ERIGERON, L. Herbs. Leaves usually sessile. Heads many-flowered, flat or nearly hemispherical, the rays numerous, narrow, pistillate. Scales of the involucre narrow and overlapping but little. DICOTYLEDONOUS PLANTS 229 Akenes flattish, crowned with a single row of hair-like bristles, or sometimes with shorter bristles or scales outside these. Disk yellow, rays white, pinkish, or purple. 1, E. annuus, Pers. Common FLEasane. Annual or biennial. Stem grooved and stout, branching, 2-5 ft. high, with scattered hairs; lowest leaves petioled, ovate, coarsely toothed, those higher up the stem successively narrower, sessile; heads in a large loose corymb ; rays short, white or purplish. Fields and waste ground. 2. E. strigosus, Muhl. Daisy Fieasane. Annual or biennial. Considerably resembling the preceding species, but with entire _ leaves, smaller and less branched stem, smaller heads, and longer rays. Fields and pastures. ; , 3. E. bellidifolius, Muhl. Roprn’s PLanrarin. Perennial. Soft- hairy; stems sometimes throwing out offsets from the base; simple, erect, 1-2 ft. high; root-leaves, obovate-obtuse, somewhat serrate; stem-leaves few, lance-oblong, acute, clasping; heads rather large, 1-9, on long peduncles, with 50-60 long, rather broad, bluish-purple or reddish-purple rays. Thickets and moist banks. 4. E. philadelphicus, L. Perennial. Rather hairy; stems slender, about 2 ft. high; root-leaves spatulate and toothed; stem-leaves usually entire and strongly clasping, sometimes with a heart-shaped or eared base; heads several, small, long-petioled ; rays exceedingly numerous, thread-like, reddish-purple or flesh-color. In damp soil. iI. COREOPSIS, L. Annual or perennial herbs. Leaves opposite or the upper alternate, entire or pinnately divided. Heads radiate, solitary or corymbed, many-flowered ; bracts in 2 rows of about 8 each, the inner membranaceous and appressed, the outer narrower and spreading; receptacle chaffy. Ray-flowers neutral; disk- flowers tubular, perfect. Akenes compressed, oval to oblong, often winged. Pappus of 2 scales or bristles, or wanting.* 1. C. tinctoria, Nutt. GarpEn Corrorsis. Annual. Stem erect, smooth, branched, 2-3 ft. high. Leaves 2-3 times pinnately divided, the divisions linear, lower leaves petioled, the upper often sessile and entire. Heads 1-14 in. wide, on slender peduncles ; inner bracts brown with scarious margins, outer bracts very short. Ray-flowers about 8, yellow with a brown base, 3-lobed at the apex. Akenes linear. Pappus minute or none. Common in gardens.* 2. C. lanceolata, L. Ticwserp. Perennial; stem slender, erect or ascending, smooth or slightly downy below, simple, 9-15 in. high. Leaves opposite, the lower spatulate to elliptical, sometimes lobed, 230 FOUNDATIONS OF BOTANY on long, hairy-fringed petioles, the upper lanceolate, sessile. Heads few, on long peduncles; bracts ovate-lanceolate, the outer narrower. Ray-flowers 6-10, rays 3-5-lobed, bright yellow. Akenes oval, broadly winged, warty. Pappus of 2 teeth. On rich, dry soil S. and E.* 3. C. auriculata, L. Running TicksEEep. Perennial; stem ascend- ing or decumbent, weak, smooth, nearly simple, 6-15 in. long. Leaves ovate to oval, entire or with 2-4 small and rounded lobes at the base, downy, long-petioled. Heads 1-14 in. wide, few or single; outer bracts narrower than the inner. Rays 6-10, mostly 4-toothed at the apex ; chaff as long as the flowers. Akenes oblong, the wings narrow and thickened. Pappus of 2 minute teeth.. In rich woods.* Iv. RUDBECKIA, L. Perennial or biennial. Leaves alternate, entire or lobed. Heads radiate, long-peduncled, many-flowered; bracts imbri- cated in 2-3 series, spreading; receptacle convex or long-coni- cal, with concave, chaffy scales. Ray-flowers yellow, neutral ; disk-flowers purple to brown, perfect. Akenes smooth, 4-angled, truncate. Pappus a few short teeth or wanting.* 1. R. hirta, L. Conr-FLower. Annual or biennial; stem erect, rough-hairy, simple or branched, 2-3 ft. high. Leaves lanceolate to oblong, thick, obscurely serrate, rough-hairy, 3-ribbed, the lower petioled, the upper sessile. Heads few, long-peduncled; bracts rough-hairy, spreading. Ray-flowers 10-20, orange-yellow; disk- flowers purplish brown. Chaff acute, hairy at the apex. Pappus none. On dry, open ground. V. HELENIUM, L. Annual or perennial. Leaves alternate, forming wings on the stem. Heads radiate, peduncled, many-flowered; bracts in 2 series, the outer linear and spreading, the inner few and scale-like; receptacle naked, convex or oblong. Ray-flowers pistillate and fertile, or neutral, the rays wedge-shaped, 3-5- lobed; disk-flowers perfect, tubular, 4-5-lobed. Akenes top- shaped, hairy, ribbed. Pappus of 4-5 entire, toothed or awned scales.* 1, H. nudiflorum, Nutt. Snerzewerp. Perennial; stem slender, erect, downy, branched above, 1-2 ft. high. Leaves lanceolate, entire or slightly toothed, the lower petioled, the upper sessile. DICOTYLEDONOUS PLANTS 231 Heads numerous. Ray-flowers 10-15, neutral, yellow or yellow and brown ; disk-flowers purple. Akenes hairy on the ribs; pappus of ovate, minutely toothed, awned scales. Common on river banks S.* VI. ANTHEMIS, L. Aromatic or ill-scented herbs. Leaves finely pinnately divided. Heads many-flowered, with ray-flowers. Rays pis- tillate or neutral. Involucre of many small, dry, close-pressed scales. Akenes nearly cylindrical, generally ribbed; barely crowned or naked at the summit. 1. A. Cotula, DC. Mayweep, DoG-rENNEL. Leaves irregularly cut into very many narrow segments. Heads small, produced all summer. Disk yellow. Rays rather short, white, neutral. A low, offensive-smelling annual weed, by roadsides and in barnyards. Vil. ACHILLEA, L. Perennial; leaves alternate, pinnately divided. Heads with ray-flowers in a terminal corymb; involucral bracts imbricated in several series, the outer shorter; receptacle chaffy. Ray- flowers white or pink, pistillate and fertile; disk-flowers per- fect, tubular, 5-lobed. Akenes oblong, compressed, slightly margined. Pappus none.* 1. A. Millefolium, L. Yarrow. Stems often clustered, erect from a creeping rootstock, simple, downy or woolly, 1-2 ft. high. Leaves lanceolate or oblong, the segments finely cut and divided, smooth or downy, the lower petioled, the upper sessile. Heads small, numerous, in flat-topped corymbs; bracts downy. Ray-flowers 4-5, white or pink, rays 3-lobed at the apex. Common in old fields.* VII, CHRYSANTHEMUM, Tour. Perennials, with toothed, pinnately cut or divided leaves. Heads nearly as in the Anthemis, except that the ray-flowers are pistillate. 1. C. Leucanthemum, L. Oxrye Daisy, WHITEWEED, BULL’s- EYE, SHERIFF Pink. Stem erect, unbranched or nearly so, 1-2 ft. high; root-leaves oblong-spatulate, petioled, deeply and irregularly toothed ; stem-leaves sessile and clasping, toothed and cut, the upper- most ones shading off into bracts. Heads terminal and solitary, 232 FOUNDATIONS OF BOTANY large and showy, with a yellow disk and many white rays. A trouble- some but handsome perennial weed. Introduced from Europe, chiefly E. 2. C. frutescens, L. Manrcuerite. Erect, branching, perennial, woody below, smooth, and with a pale bloom. Divisions of the leaves linear, with the uppermost leaves often merely 3-cleft bracts. Heads long-peduncled, showy, with a yellow disk and large, spread- ing white rays. Cultivated in greenhouses; from the Canary Islands. IX. SENECIO, Tourn. Annual or perennial; stems often hollow. Leaves alternate, entire or pinnately divided. Heads with or without rays, in terminal corymbs; bracts mostly in a single row, often witha few shorter ones at the base; receptacle naked or pitted. Ray- flowers yellow or orange, pistillate and fertile when present; disk-flowers tubular, perfect. Akenes cylindrical or com- pressed, not beaked or winged, 5-10-ribbed, downy. Pappus of numerous, slender, white hairs.* 1. S. tomentosus, Michx. WooLtLy RaGweep. Perennial; woolly throughout ; stem stout, erect, mostly simple, 2-3 ft. high. Lower leaves ovate to oblong, crenate or entire, obtuse, long-petioled; stem- leaves few, elliptical to oblanceolate, serrate or toothed, acute, sessile. Heads radiate, 2 in. wide, on slender peduncles; bracts narrow, becoming smooth. Ray-flowers 12-15, yellow. Akenes hairy. On damp soil.* 2. S. aureus, L. Go~pEN RAGweeEp. Perennial; stems often tufted, erect, slender, woolly when young, branched above, 18-30 in. high. Lower leaves broadly ovate, obtuse at the apex, heart-shaped at the base, crenate, long-petioled; stem-leaves lanceolate and often pinnatifid, the upper small and sessile. Heads radiate, corymbed, on slender peduncles; ray-flowers 8-12, bright yellow. Akenes smooth. On wet soil; very variable.* : 3. S. lobatus, Pers. ButTTrerwerp. -Annual; stem erect, ridged, hollow, often woolly when young, and becoming smooth with age, branched above, 1-3 ft. high. Leaves lyrate-pinnatifid, thin, the lower petioled, the upper sessile. Heads radiate in a terminal corymb; bracts linear, acute. Ray-flowers about 12, yellow. Akenes slightly rough-hairy on the angles. Pappus rough, longer than the involucre. Common on low ground.* DICOTYLEDONOUS PLANTS 233 X. CENTAUREA, L. Herbs. Leaves entire or cut, often spiny-toothed. Heads single; involucre ovoid or globose (Fig. 22); bracts closely overlapping, entire, dry and membranaceous. Corollas all tubular, oblique or 2-lipped, inflated above; the outer ones usually larger and neutral, the inner flowers perfect; lobes 5, slender. Akenes flattened. Pappus hairs short, slender, rough. 1. C. Cyanus, L. Bacuetor’s Burron.’ Stem erect, slender, grooved, 1-2 ft. high, somewhat branched. Leaves acute, sessile, narrow, entire or few-lobed. Peduncles covered with cottony wool. Heads 4-1 in. in diameter, cobwebby. Ray-like flowers few, large, bright blue or pink; those of the disk smaller. Cultivated from Europe and escaped from gardens. XI. CIRSIUM, Tourn. Biennial or perennial; stem erect, simple or branched. Leaves alternate, prickly, often forming wings on the stem. Heads discoid, terminal and solitary or corymbed, many-flow- ered; bracts overlapping in many series, the outer shorter, usually spine-pointed; receptacle bristly. Corollas purplish or nearly white, the tube slender, deeply 5-cleft. Akenes oblong, 4-angled, smooth or ribbed. Pappus of numerous simple or plumose bristles.* 1. C. altissimum, Spreng. Tarx Txistie. Perennial or bien- nial; stem stout, very leafy, downy or woolly, branched 4-10 ft. high ; leaves rough-downy above, hoary beneath, fringed with fine prickles, not forming wings on the stem, the lower petioled and often pinnately cut, the upper sessile and éntire. Heads ovoid, 1 in. in diameter ; bracts viscid, webby when young, all except the inner ones tipped with weak and spreading bristles. Flowers light purple. Common in fields, woods, and waste places.* 2. C. horridulum, Michx. YeLtow Tuistix. Biennial or peren- nial; stem erect, stout, woolly when young, becoming smooth, often purple, branched 1-3 ft. high. Leaves pinnately cut, with very spiny teeth, mostly sessile and clasping, smooth and green on both sides. Heads large, surrounded by a whorl of linear-oblong, comb- like leaves ; involucral bracts linear, ciliate, not spine-tipped. Flowers purple or yellowish. On sandy soil E. and 8.* 934 FOUNDATIONS OF BOTANY Ii. LIGULIFLORZA. XII. KRIGIA, Schreber. Small, annual or perennial herb. Leaves mostly radical, toothed or lyrate. Heads several-many-flowered; scales of the involucre about 2-rowed, thin. Akenes short, truncate. Pappus in 2 rows, the outer one of thin, blunt, chaffy scales, the inner one of slender bristles. Corollas yellow. 1. K. virginica, Willd. Annual; scapes usually 2-5 from one root, slender. Leaves mostly: lyrate, smooth and with a bloom, the earlier ones rounded or spatulate. Scales of the involucre linear- lanceolate, nearly equal, spreading. Akenes top-shaped, reddish- brown, crowned with 5 wedge-obovate scales and 5 rough white bristles. 2. K. Dandelion, Nutt. Perennial, from slender tuber-bearing roots. Scapes leafless, 6-18 in. high. Leaves entire or nearly so, varying from spatulate-oblong to linear-lanceolate. Akenes more slender than in No. 1. Pappus consisting of 10-15 small, oblong, chaffy scales and 15-20 bristles. In moist ground, especially S. © 3. K. amplexicaulis, Nutt. Stem 12-18 in. high, often 2-3 from the same root, mostly 2-forked or 3-forked at the summit. Root- leaves 3-6 in. long, lanceolate, entire, toothed -or rarely pinnately cut, clasping at the base; stem-leaves 1-3. Akenes and pappus about as in No. 2. Moist banks. XII. CICHORIUM, L. Perennial herbs. with spreading branches; juice milky. Leaves radical and alternate, toothed or pinnately cut. Heads axillary ; involucre cylindrical, bracts in 2 rows, the inner row erect, coherent at the base, the outer shorter; receptacle flattish. Corollas blue, pale pink, or yellow. Upper part of the style and its slender arms hairy. Akenes crowded on the hardened receptacle, firmly covered by the stiff involucre, obovoid or top-shaped, not beaked. Pappus 1 or 2 rows of short scales. 1. C. Intybus, L. CuHicory, BLuE Danpe1ion, BLUE SaILors. Root very long, stout, and fleshy. Stem 1-3 ft. high, angled and grooved ; branches straight and stiff. Root-leaves and lower stem- leaves runcinate ; upper stem-leaves oblong or lanceolate, clasping, DICOTYLEDONOUS PLANTS 935 those of the branches reduced to bracts. Flowers very showy, usually bright blue, rarely pinkish-white. Introduced from Europe; a troublesome weed in grass-lands and common in waste places, particularly in New England. 4 XIV. HIERACIUM, L. Perennial herbs, often covered with glandular or star-shaped hairs; juice milky. Leaves alternate. Heads solitary, or in corymbs or panicles; bracts of the involucre many, overlap- ping, unequal; receptacle flattish, naked, pitted. Corollas yellow, rarely orange; arms of the style slender and upper part of the style hairy. Akenes angled or grooved, not beaked. Pappus hairs in a single row, simple, stiff, tawny, or brownish, brittle. * 1. H. venosum, L. RartTyesnaxe WeErEp. Stem scape-like, usually leafless or nearly so, smooth, 1-2 ft. high. Root-leaves 2-5 in. long, obovate or ovate-oblong, generally purple-veined. Heads rather large, yellow, in a loose panicled corymb. Dry hills and roadsides, and in pine woods E, XV. LEONTODON, L. Perennial, scape-bearing herbs; juice milky. Leaves all radical, toothed or pinnatifid, often runcinate. Heads on simple or branched scapes, yellow; bracts of the involucre many, in several rows, the anther smaller; receptacle flat, naked.. Arms of the style linear, obtuse, hairy. Akenes cylin- drical, grooved, transversely wrinkled; beak short; pappus hairs stiff, in 1 or 2 rows. 1. L. autumnalis, L. Scape usually branching, 5-15 in. high, bracted; peduncles enlarged above. Rootstock truncate. Heads 13-1 in. or more in diameter; involucre top-shaped or bell-shaped. Pappus of a single row of tawny hairs. Fields and roadsides, especially N. E. Introduced from Europe. XVI. TARAXACUM, Haller. Stemless, perennial or biennial herbs. Leaves in a flattish tuft, pinnately cut or runcinate (Fig. 38). Head many- flowered, large, solitary, yellow, borne on a hollow scape, which 236 FOUNDATIONS OF BOTANY is short at first but lengthens after flowering. Involucre com- posed of a single row of long, erect, inner scales and a set of much shorter ones outside and at the base of the former ones. Akenes cylindrical or spindle-shaped, with 4-5 rough ribs, the apex tapering into a bristle-like beak which bears a short, broadly conical tuft of soft white hairs. 1. T. officinale, Weber. Danprxion. Outer involucre reflexed ; inner involucre closing over the head, after the flowers are withered, and remaining shut for some days, then opening and allowing the akenes to form a globular: head. Root stout, bitter, medicinal. Young leaves eaten as a pot-herb (“greens”) in spring— the plant often cultivated for the leaves by market-gardeners. XVII. PYRRHOPAPPUS, DC. Annual or biennial; stem erect, leafy below, nearly naked above, smooth. Leaves oblong, toothed or pinnatifid. Heads large, long-peduncled ; involucre cylindrical or spreading, the inner row of bracts erect, united at the base, the outer rows shorter and spreading; receptacle naked. Flowers yellow; rays truncate, 5-toothed at the apex. Akenes oblong, 5-ribbed, narrowed above into a long and slender beak; pappus soft, tawny, with a short, soft-hairy ring at the base.* 1. P. carolinianus, DC. Fartsz Danprxion. Annual or bien- nial; stem glabrous, furrowed, branched above, 2-3 ft. high. Lower leaves lanceolate to oblong, entire, toothed or pinnatifid, narrowed into a margined petiole, the upper sessile, bract-like, entire. Heads few, long-peduncled, peduncles and involucre sometimes finely downy; inner bracts calloused at the apex, the outer awl-shaped and spreading. Akenes much shorter than the thread-like beak. Common in fields.* XVII. LACTUCA, Tour. Annual, biennial, or perennial; stems leafy. Leaves entire to pinnately cut. Heads panicled; involucre cylindrical, bracts unequal, overlapping in 2 or more rows, the outer shorter; receptacle naked. Flowers blue, yellow, or white; rays truncate, 5-toothed at the apex. Akenes compressed, ribbed, the apex contracted into a slender beak, which is enlarged into a disk bearing the soft, hairy, white or tawny pappus.* DICOTYLEDONOUS PLANTS 237 1. L. canadensis, L. Witp Lertucr. Biennial; stem erect, smooth, hollow, branched above, 3-10 ft. high. Leaves lanceolate to spatulate, pale beneath, the lower petioled and pinnately cut, the upper sessile, clasping, and nearly entire. Heads numerous, about 20-flowered. Flowers yellow; akenes oval, flat, 1-ribbed on each side, minutely roughened, about as long as the beak. Pappus white. In waste places.* 2. L. acuminata, Gray. Biue Lxetrucre. Stem very leafy, smooth, paniculately branched above, 3-6 ft. high. Leaves ovate to lanceolate, taper-pointed, often hairy beneath, the lower on winged petioles and often sinuate-lobed, the upper sessile. Heads racemed, on divergent and bracted peduncles. Flowers blue. Akenes slightly compressed, beak very short. Pappus white. In waste places.* XIX. SONCHUS, L. Annual or perennial. Leaves mostly toothed or pinnately cut, prickly margined. Heads in corymbs or panicles; bracts in several series, the outer shorter; receptacle naked. Flowers yellow, rays truncate, 5-toothed at the apex. Akenes oval to oblong, compressed, ribbed, truncate at the apex. Pappus of numerous soft white hairs.* 1. S. oleraceus, LL. Sow Turstix. Annual; stem erect, branched, smooth, 2-6 ft. high. Leaves spiny-toothed, the lower long-petioled, very irregularly cut or pinnatifid, the upper clasping by an eared base. Involucre downy when young. Akenes channeled and trans- versely wrinkled. In waste places on very rich soil.* 2. S.asper, Vill. Srrny Sow Tuistie. Annual; stem erect, smooth, branched but little, 2-6 ft. high. Leaves undivided, spatu- late to oblanceolate, fringed with spiny teeth, the lower narrowed into a petiole, the upper clasping by an eared base, the ears rounded. Heads numerous ; involucre glabrous. Akenes flattened, margined, 3-nerved on each side, smooth. In waste places.* GLOSSARY OF TECHNICAL TERMS USED ONLY IN THE FLORA Abortive, imperfectly developed. Appressed, lying flat throughout its length, used of such parts as bracts. Awl-shaped, narrow and tapering to a point. Awned, having a bristle-like ap- pendage. Awnless, not awned. Capitate, (1) having a round head like the stigma of a primrose ; (2) growing in heads. Carpellary, relating to a carpel. Chaff, small membranous scales, such as are found on disks of Composite. Clasping, partly surrounding the stem, said of the bases of leaves. Claw, the narrowed base of a petal. Cleft, cut halfway down. Coated (bulbs), those with scales which completely cover them, as in the onion. Cone, the fruit of pines, etc., with ovule-bearing scales. Connate, united, said of opposite leaves which appear as if grown together at their bases. : Cordate, heart-shaped. Corm, a bulb-like, fleshy stem or base of a stem. 239 Crown, an inner appendage to a petal or to the throat of the co- rolla. Deciduous, falling as petals do after blossoming, or as leaves of most trees except evergreens do. Declined, directed obliquely. Decumbent, reclining, but with the summit somewhat erect. Dehiscent, splitting into definite parts. Diffuse, spreading widely or loosely. Disk, (1) an outgrowth of the re- ceptacle within the calyx or within the corolla and stamens ; (2) the central part of the head (all but the rays) in Composite. Dissected, deeply divided or cut into many segments. _Drupe, a stone-fruit such as a peach or a plum. Equitant, leaves astride of those within them, thus appearing in a cross-section like the diagram, << Even-pinnate, abruptly pinnate,i.e., with no leafiet at the end. Fascicle, a close cluster or bundle of flowers, leaves, stems, or roots. ‘ 240 Fertile, capable of producing fruit ; fertile flowers, those which have pistils. Filiform, thread-shaped. Fleshy, succulent, thick and full of sap. Funiculus, the little stalk which connects a seed or ovule with the placenta. Gland, (1) astructure which secretes something, as the knobs on the hairs of sundew ; (2) any knob or swelling. Herbaceous, with no stem above- ground which lives through the winter, not woody or shrubby. Indefinite, too many to be easily counted. Indehiscent, not splitting open reg- ularly. Involucrate, provided with an in- volucre. Keel, the two anterior and united petals of a papilionaceous corolla. Key, a winged fruit like that of the ash or maple. Limb, the border or spreading part of a gamopetalous calyx or co- rolla. Lobed, having divisions, especially rounded ones. Nerved, having simple or un- branched veins or slender ribs. Ob, in composition, signifies in- versely, as obcordate, inversely heart-shaped. FOUNDATIONS OF BOTANY Odd-pinnate, pinnate with a single leaflet at the end of the midrib. Palate, a projection in the throat of a corolla. Papilionaceous, butterfly - shaped, like the corolla of the sweet pea. Papillose, covered with papille or minute projections, like the human tongue. : Pappus, tufts of hair or other ob- jects, representing the limb of the calyx in Composite. Perfoliate, with the stem appar- ently growing up through a leaf, as in some honeysuckles. Persistent, not deciduous. Pinnatifid, pinnately cleft. Pistillate, having pistils but not stamens. Pubescent, clothed with soft hair, downy. Punctate, marked with dots, de- pressions, or translucent glands. Radical, arising from the root or a very short stem at its summit, as the leaves of the dandelion. Refiexed, bent or turned abruptly downward or backward. Root-parasite, a plant parasitic on the roots of another. Sagittate, arrow-shaped. Scape, a leafless flower-stalk aris- ing from the ground, as in the dandelion and cyclamen. Scarious, thin, dry, and membra- nous, not green. Sessile, without a stalk. Simple (stem), unbranched. GLOSSARY Spadix, a spike with a fleshy axis, like that of the Indian turnip or the ‘calla.”’ Spathe, a large bract which encloses a flower-cluster, often a spadix. Staminate, having stamens only. Standard, the posterior petal of a papilionaceous corolla, Sterile, (1) barren, as a flower with- out a pistil or an antherless sta- men; (2) staminate or male, said of flowers. Striate, marked with fine longitudi- nal parallel lines. Sub- (in composition), somewhat, as subglobose. Subtend, to extend beneath, as a bract in the axil of which a flower is borne. Succulent, fleshy or juicy. Three-ranked, with three vertical rows on a stem or axis. 241 Throat, the top of the tubular part of a gamopetalous corolla. Truncate, appearing as if cut squarely off, as the leaves of the tulip-tree. Tubercled, covered with warty growths. Tubercular, having tubercles, or like a tubercle. Two-ranked, with two vertical rows on a stem or axis. Utricle, a small bladdery ovary- wall. Versatile, turning freely on its sup- port, as an anther on its filament. Whorled, arranged in a circle around an axis, as the leaves of some lilies. Wings, the side-petals of a papilio- naceous flower. Abies, 17. Abutilon, 148. Acanthacee, 210. . Acanthus Family, 210. Acer, 141]. Aceraceze, 140, 141. Achillea, 231, Aconitum, 80. Acorus, 25. Acta, 79. Adder’s-tongue, 36. Adlumia, 92. Esculus, 142. Agrostemma, 73. Aizoacez, 69. Alder, 55, 139. Alfalfa, 124. Alisma, 21. Alismacez, 21. Alleghany Vine, 92. Allium, 34. Alnus, 54, 55. Alum Root, 103. Alyssum, 98, 99. Amaryllidacee, 42. Amaryllis Family, 42. Amelanchier, 110. American Aspen, 47. Anianthium, 32, 33. Amorpha, 126. Ampelopsis, 146. Amsonia, 178, 179. Anagallis, 174. Anarcardiacez, 1387. INDEX Andromeda, 168. Anemone, 80, 81. Anemone, Rue, 82. Anemonella, 82. Angiosperms, 20. Anonacee, 88. Anthemis, 231. Antirrhinum, 203. Apetalous Division, 6. Aphyllon, 208. Apocynacee, 178. Apocynum, 179, 180. Apple, 109. Aquifoliacez, 138. “Aquilegia, 79. Arabis, 98. Aracee, 23. Aralia, 157, 158. Araliacez, 157. Arbor Vite, 18. Arbutus, Trailing, 169. Arctostaphylos, 169. Ariseema, 24, 25. Aristolochia, 65. Aristolochiacez, 64, 65. Arrowhead, 22. Arrowwood, 216, 217. Arum Family, 23. Asarum, 65. Asclepiadacez, 180, 181. Asclepias, 181, 182. Ash, 134, 175. Ash, Mountain, 109. Asimina, 88. 243 244 FOUNDATIONS OF BOTANY Asparagus, 38. Asp, Quaking, 47. Aspen, American, 47. Astragalus, 127, 128. Atamasco Lily, 43. Avens, 114, 115. Babies’ Toes, 134. Bachelor’s Button, 233. Bald Cypress, 18. Balsam, 143, Balsam Family, 143. Balsam Fir, 17. Balsaminacez, 143. Bamboo-vine, 42. Baneberry, 79. Baptisia, 122. Barberry, 84. Barberry Family, 84. Barren Strawberry, 113. Basswood, 147. Bastard Toad-flax, 64. Bayberry, 49. Bayberry Family, 49. Beaked Hazelnut, 53. Bearberry, 169. Bedstraw, 215. Beech, 56. Beech Family, 55. Beggar’s Lice, 190. Begonia, 152, 153, 154. Begoniacez, 152. Begonia Family, 152. Bell Flower, 223. Bell Flower Family, 223. Bellis, 228. Bellwort, 33. Benjamin, 41. Berberidacee, 84. Berberis, 84, 85. Berchemia, 144. Betula, 58, 54. Betulacez, 51. Bignonia, 206. Bignoniacez, 206. Bignonia Family, 206. Bindweed, 184. Birch, 53, 54. Birch Family, 51. Bird’s Pepper, 94. Bishop’s Cap, 103. Bitter Cress, 97. Bittersweet, 139, 199. Black Alder, 139. Blackberry, 112. Black Gum, 164. Black Haw, 217. Black Walnut, 50. Bladder-nut, 140. Bladder-nut Family, 140. Bladderwort, 209, 210. Bladderwort Family, 209. Bleeding Heart, 92. Bloodroot, 90. Blue Beech, 52. Bluebell, 187. Bluebells, 190. Blueberry, 170. Blue Cohosh, 85. Blue Dandelion, 234. Blue Devils, 191. Blue Flag, 45. Blue Sailors, 234. Blue Thistle, 191. Bluets, 213. Blue Valerian, 187. Blueweed, 191. Borage Family, 188. Borraginacez, 188. Boston Ivy, 146. Bouvardia, 214. Box Elder, 141. Brassica, 95, 96. Breeches Flower, 91. ' Bridal Wreath, 108. Brooklime, 204. Broom-rape Family, 208. Broussonetia, 62. Brunella, 196. Buck-bean, 178. Buckeye, 142. Buckeye Family, 142. Buckthorn, 144. Buckthorn Family, 143. Buckwheat, 67. Buckwheat Family, 66. Buffalo Apple, 128. Buffalo Pea, 128. Bull Nut, 51. Bull’s-eye, 231. Bulrush, 24. Bunch-berry, 163. Bur, Buffalo, 200. Bur, Sand, 200. Butter and Eggs, 203. Buttercup, 83. Buttercup Family, 77, 78. Butternut, 50. Butterweed, 232. Button Snakeroot, 159. Buttonwood, 105. Cactacex, 154. Cactus Family, 154. Calamus, 25. Calico Bush, 168. Callicarpa, 193. Caltha, 78. Calycanthaceex, 87. Calycanthus, 87, 88. Calycanthus Family, 87. Calystegia, 183, 184. Camassia, 36, 37. INDEX 245 Campanula, 228. Campanulacee, 223..- Campanula Family, 228. Cancer Root, 208. Cannabis, 62." Cantaloupe, 222. Caper Family, 99. Capparidacee, 99. Caprifoliaces, 215. Capsella, 98. Caraway, 160. Cardamine, 97. Carnation, 75. Carpenter-weed, 196. Carpet-weed, 70. Carpinus, 51, 52. Carrion Flower, 41. Carrot, 162. Carum, 160. Carya, 50, 51. Caryophyllacez, 71, 72. Castanea, 56. Castilleia, 205. Catalpa, 207. Cat-brier, 42. Catchfly, 74. Catnip, 195. Cat-tail, 20. Cat-tail Family, 20. Caulophylium, 85. Ceanothus, 144, 145. Cedar, 18, 19. Celandine, 90. Celastracez, 139. Celastrus, 139. Celtis, 60. Centaurea, 233. Cerastium, 72. Cercis, 120. Cereus, 155. Chamelirium, 32. 246 FOUNDATIONS OF BOTANY Charlock, 95, 96. Cheeses, 148. Chelidonium, 90. Chenopodiacee, 68. Chenopodium, 68, 69. Cherry, 117. Chestnut, 56. Chickweed, 72. Chickweed Wintergreen, 173. Chicory, 284. Chimaphila, 164, 165. Chinese Sacred Lily, 43. Chinquapin, 56. Chinquapin, Water, 76. Chionanthus, 176, 177. Chocolate Root, 115. Chokeberry, 109. Chokecherry, 117. Chokepear, 109. Chrysanthemum, 231, 232. Cichorium, 234. Cinquefoil, 114. Circa, 157. Cirsium, 233, Citrullus, 222. Citrus, 133. Cladrastis, 121. Claytonia, 70. Clematis, 82. Cleome, 100. Clove Pink, 75. Clover, 124, 125. Cochlearia, 95. Coffee Tree, 121. Cohosh, 85. Columbine, 79. Comandra, 64. Comfrey, 189. Commelina, 27. Commelinacee, 26. Composite, 224-228. Composite Family, 224-228. Cone-flower, 230. ‘ Conifer, 18. Conopholis, 208. Convallaria, 40. Convolvulacex, 183. Convolvulus, 184. Convolvulus Family, 183. Coptis, 79. Coreopsis, 229, 230. Cornacez, 162. Corn Cockle, 73. Cornel, 163. Corn Gromwell, 191. Corn Salad, 221. Cornus, 162, 163. Corydalis, 93. Corylus, 52, 53. Cottonwood, 48. Cow Lily, 77. Cow Parsnip, 162. Cowslip, ‘78. Crab Apple, 109. Cranberry, 171. Cranberry Tree, 216. Cranesbill, 180. Crategus, 110, 111. Creepers, 183. Creeping Charley, 195. Cress, 97. Crinkle Root, 97. Crocus, 45. Cross-vine, 206. Crowfoot, 83. Crowfoot Family, 77; 78. Crown Imperial, 36. Crown of Thorns, 186. Crow’s Foot, 97. Crow-victuals, 195. Cruciferx, 93, 94. Cucumber, 222, Cucumis, 222. Cucurbita, 222. Cucurbitacez, 221. Currant, 104. Cuscuta, 183. Cydonia, 108. Cynoglossum, 189. Cyperacer, 23. Cypress, 18, 187. Cypress Vine, 184. Cypripedium, 46. .Cytisus, 123. Daffodil, 43. Daffy, 43. Daisy, 228, 231. Dakota Turnip, 126. Dandelion, 236. Datura, 200, 201. Daucus, 162. Dayflower, Virginia, 27. Day-lily, 34. Dead Nettle, 196. ‘Deerberry, 171. Delphinium, 80. Dentaria, 97. Deptford Pink, 75. Desmanthus, 119, 120. Deutzia, 104. Devil’s Bit, 32. Dewberry, 112. Dianthera, 211. Dianthus, 75. Dicentra, 91, 92. Dicotyledonous Plants, 47. Diervilla, 219, 220. Diospyros, 174. Dock, 66, 67. Dodecatheon, 171, 172. Dogbane, 180. Dogbane Family, 178. INDEX 247 Dogberry, 109. Dog-brier, 42. Dog-bur, 189. Dog-fennel, 231. Dog’s-tooth Violet, 36. Dogwood, 163. Dogwood Family, 162. Dogwood, Poison, 138. ‘Dragon Root, 25. Dutchman’s Breeches, 91. Dutchman’s Pipe, 65. Dutchman’s Pipe Family, 64, 65. Ear Drops, 92. Easter-flower, 43. Ebenacee, 174. Ebony Family, 174. Echinocystis, 222. Echinospermum, 189, 190. Echium, 191. Elder, 215, 216. Elder, Wild, 157. Elm, 60. Elm Family, 59. Enchanter’s Nightshade, 157. English Ivy, 157. English Walnut, 50. Epigza, 169. Ericacez, 166, 167. Erigenia, 159, 160. Erigeron, 228, 229. Eryngium, 158, 159. Erythronium,.36. Eschscholtzia, 90. Euonymus, 139, 140. Euphorbia, 136, 137. Euphorbiacee, 135. Eutoca, 188, Evening Primrose Family, 156. Eyebright, 213. 248 FOUNDATIONS OF BOTANY Fagaces, 55. Fagus, 55, 56, Fairycup, 103. False Buckwheat, 67. False Dandelion, 286. False Indigo, 126. False Mitre-wort, 102. False Spikenard, 38. Farkleberry, 171. Feverwort, 218. Field Garlic, 34. Figwort Family, 201, 202. Fir, 17. Fire Pink, 74. Flag, 45, 46. Flax, 133. Flax Family, 132. Fleabane, 229. Fleur-de-lis, 45, 46. Flowering Maple, 148. Flowering Moss, 186. Fly Poison, 38. Forget-me-not, 190, 191. Forsythia, 176. Fragaria, 118. Fraxinus, 175. French Mulberry, 193. Fringe Cap, 108. Fringe Tree, 177. Fritillaria, 35. Fuchsia, 156. Galium, 214, 215. Garden Columbine, 79. Garden Sage, 198. Garget Root, 69. Garlic, 34. Gaylussacia, 169, 170. Gentianacez, 177. Gentian Family, 177. Geraniacex, 129, 130. Geranium, 130, 131. Geranium Family, 129, 130. Geum, 114, 115. Gill-over-the-ground, 195. Gillyflower, 99. Ginseng Family, 157. Gleditschia, 121. Golden Alexanders, 161. Golden Chain, 123. Gold Thread, 79. Gooseberry, 104. Goosefoot, 69. Goosefoot Family, 68. Goose Grass, 214. Gourd Family, 221. Graminez, 23. Grape, 145, 146. Grape Family, 145. Grass Family, 23., .Grass Pink, 75. e Gratiola, 204. Graveyard Moss, 137. Green-brier, 42. Green Dragon, 25. Gromwell, Corn, 191. Ground Ivy, 195. Ground Pink, 186. Ground Plum, 128. Guinea-hen Flower, 35. Gum, Black, 164. Gymnocladus, 120, 121. Gymnosperms, 13. Gypsy Weed, 205. Hackberry, 60. Hackmatack, 18. Harbinger of Spring, 160. Hardback, 108. Harebell, 223. Haw, 110, 111, 217, Hazelnut, 52, 53. Heal-all, 196. Heart’s-ease, 151. Heath Family, 166, 167. Hedge Mustard, 95. Helenium, 230. Heliotrope, 189, Heliotropium, 189. Hellebore, White, 32. Hemerocallis, 33, 34. Hemlock, 17. Hemp, 62, Hen-bit, 196. Hepatica, 81. Heracleum, 161, 162. Herb Robert, 130. Heuchera, 103. Hickory, 51. Hieracium, 235. High-bush Cranberry, 216. Hippocastanacesz, 142. Hobble-bush, 216. Holly, 138, 139. Holly Family, 138. Honey Locust, 121. Honeysuckle, 167, 218-220. Honeysuckle Family, 215. Hop Clover, 125. Hop-tree, 134. Horehound, 195. Hornbeam, 52. Horse-brier, 42. Horse-chestnut, 142. Horse-gentian, 218. Horse Nettle, 199. Horse-radish, 95. Hound’s-tongue, 189. Houstonia, 213. Hoya, 183. Huckleberry, 170, 171. Hyacinth, 37. Hyacinthus, 37. INDEX 249 Hydrophyllacex, 187. Hydrophyllum, 187, 188. Hypericacex, 148. Hypericum, 149. Hypoxis, 43. Ice Plant, 69. Ice-plant Family, 69. Tlex, 138, 189. Impatiens, 143. Indian Chief, 172. Indian Cress Family, 132. Indian Hemp, 180. Indian Paint, 191. Indian Pink, 205. Indian Pipe, 166. Indian Poke, 32. Indian Turnip, 25. Indigo, 122. Indigo, False, 126. Innocence, 213. Ipomoea, 184, 185. Tridacez, 45. Tris, 45, 46. Tris Family, 45. Trish Potato, 200. Iron Wood, 52. Isopyrum, 78. Ivy, 138. Jack-in-the-pulpit, 25. Jacob’s Ladder, 39, 187, 203. Japanese Ivy, 146. Jatropha, 137. Jerusalem Oak, 69. Jewel Weed, 143. Jimson Weed, 201. Johnny-jump-up, 151. Jointed Charlock, 96. Juglandacez, 49, 50. Juglans, 50. 250 FOUNDATIONS OF BOTANY Juncaces, 29. Juneberry, 110. Juniper, 19. Juniperus, 19. Kalmia, 168. Kicking Colt, 143. King Nut, 51. Kinnikinnik, 163. Knawel, 73. Knot-grass, 67. Krigia, 234. Labiate, 193, 194. Laburnum, 123. Lactuca, 286, 237. Ladies’ Eardrop, 158. Lady’s-delight, 151. Lady’s-slipper, 46, 143. Lady’s Tresses, 46. Lagenaria, 222. Lamb Lettuce, 221. Lamium, 196. Larch, 18. Larix, 17, 18. Larkspur, 80. Lathyrus, 129. Lauracezx, 88, 89. Laurel, 168, 169. Laurel Family, 88, 89. Leather Flower, 82. Leguminose, 117-119. Lemon, 133. Lentibulariacee, 209. Leontodon, 235. Leonurus, 196, 197. Lepidium, 94. Lettuce, 237. Lever-wood, 52. Liguliflore, 234. - Ligustrum, 177. Lilac, 176. Liliacex, 29. Lilium, 35. Lily, 34, 35. Lily Family, 29. Lily-of-the-valley, 40. Lime, 133. Linaceez, 132. Linaria, 202, 203. Linden, 147. Linden Family, 146, 147. Lindera, 89. Linnea, 217, 218. Linum, 182, 133. Liriodendron, 87. Lithospermum, 191. Live Oak, 58. Liver-berry, 39. Liverleaf, 81. Liverwort, 81. Lobularia, 98, 99. Locust, 121, 127. London Pride, 74. Lonicera, 218, 219. Loosestrife, 173. Loranthacesx, 63. Lotus, 76. Lousewort, 206. Lungwort, 190. Lupinus, 123. Lychnis, 74. Lycium, 199. Lycopersicum, 200. Lysimachia, 173. Maclura, 61, 62. Madder Family, 212, 213. Magnolia, 86. Magnoliacez, 85, 86. Magnolia Family, 85, 86. Maianthemum, 39. Mallow, 148. Mallow Family, 147, 148. Malva, 148. Malvacex, 147, 148. Maple, 141. Maple Family, 140, 141. Marguerite, 232. Marigold, Marsh, 78. Marrubium, 195. Marsh Bell-flower, 223. Marsh Marigold, 78. Marsh Trefoil, 178. Matrimony Vine, 199. Matthiola, 99. May-apple, 85. Mayflower, 102, 169. Mayweed, 231. May Wings, 134. Meadow Buttercup, 78. Meadow Garlic, 34. Meadow Lily, 35. Meadow Parsnip, 161. Meadow Rue, 84. Medicago, 124. Medick, 124. Melilotus, 124. | Melon, 221. Menyanthes, 178. Mercury, 138. Mertensia, 190. Mignonette, 100. Mignonette Family, 100. Milkweed, 181, 182. Milkweed Family, 180, 181. Mint Family, 193, 194. Mistletoe, 64. Mistletoe Family, 63. Mitchella, 214. Mitella, 102. Mitre-wort, 102. Mollugo, 70. INDEX 251 Monkshood, 80. Monocotyledonous Plants, 20. Monotropa, 166. Moracee, 61. Morning-glory, 184, 185. Morning-glory Family, 183. Morus, 61. Moss Pink, 186. Motherwort, 197. Mountain Ash, 109. Mountain Fringe, 92. Mouse-ear Chickweed, 72. Mulberry, 61, 62, 111. Mulberry Family, 61. Mulberry, French, 1938. Mulberry, Mexican, 193. Mullein, Moth, 202. Mullein Pink, 74. Muskmelon, 222. Mustard, 95, 96. Mustard Family, 93, 94. Myosotis, 190, 191. Myrica, 49. Myricacee, 49. Narcissus, 43. Nasturtium, 96, 132. Nelumbo, 76. Nepeta, 195. Nerium, 180. Nettle, 63. Nettle Family, 62, 63. New Jersey Tea, 145. Nightshade, 199. Nightshade Family, 198. Ninebark, 107. Noble Liverwort, 81. None-so-pretty, 74. Nonesuch, 124. Nuphar, 76, 77. Nutmeg Melon, 222. 252 FOUNDATIONS OF BOTANY Nymphea, 76. Nympheacee, 75. Nyssa, 164. Oak, 57, 58, 59. Oakesia, 33. Obolaria, 177, 178. C£nothera, 156. Cinotheraceex, 156. Oleaces, 175. Oleander, 180. Olive Family, 175. Onion, 34. Opuntia, 154, 155. Orange, 133. Orange Grass, 149. Orange, Osage, 62. Orchidacez, 46. Orchis Family, 46. Ornithogalum, 37. Orobanchacez, 208. Osage Orange, 62. Osmorrhiza, 160. Ostrya, 52. Oxalidacez, 131. Oxalis, 181. Peonia, 78. Peony, 78. Paint-brush, 206. Painted Cup, 205. Pansy, 151. Papaver, 91. Papaveracez, 89, 90. Paper Mulberry, 62. Pappoose Root, 85. Parsley Family, 158. Parsnip, 161. Partridge Berry, 214. Pasque Flower, 80. Passiflora, 151, 152. Passifloracee, 151. Passion-flower, 151, 152. Passion-flower Family, 151. Pastinaca, 161. Pawpaw, 88. Pawpaw Family, 88. Pea, 129. Pea Family, 117-119. Peach, 116. Pear, 108. Pecan, 50. Pedicularis, 206. Pelargonium, 130, 131. Pennywort, 178. Pentstemon, 203, 204. Peony, 78. Pepper-and-salt, 160. Peppergrass, 94. Pepper Root, 97. Periwinkle, 179. Persimmon, 174. Petunia, 201. Phacelia, 188. Philadelphus, 103. Phlox, 185, 186. Phlox Family, 185. Phoradendron, 63, 64. Phyllocactus, 155. Physocarpus, 107. Phytolacca, 69. Phytolaccacesx, 69. Picea, 16. Pickerel Weed, 28, 29. Pickerel-weed Family, 28. Pignut, 51. Pimpernel, 174. Pine, 14, 15, 16. Pine Family, 13. Pine-sap, 166. Pine-weed, 149. Pink, 74, 75, 167, Pink Family, 71, 72. Pinus, 14. Pipe Vine, 65. Pipsissewa, 165. Pisum, 129. Pitcher-plant Family, 101. Plantaginaces, 211. Plantago, 211, 212. Plantain, 211, 212. Plantain Family, 211. Plantain, Water, 21. Platanacez, 105. Platanus, 105. Plum, 116. Podophyllum, 85. Poet’s Narcissus, 43. Poison Ivy, 138. Poison Vine, 188. Pokeberry, 69. Pokeberry Family, 69. Poke, Indian, 32. Pokeweed, 69. Pokeweed Family, 69. Polanisia, 99. Polemoniacez, 185. Polemonium, 186, 187. Polygala, 184, 135. Polygalacez, 134. Polygala Family, 134. Polygonacez, 66. Polygonatum, 39, 40. Polygonum, 67. Pomme Blanche, 126. Pontederia, 28. Pontederiacez, 28. Poor Man’s Weather-glass, 174. Poplar, 47. Poplar, White, 87. Poppy, 91. Poppy Family, 89, 90. Populus, 47, 48. INDEX 258 Portulaca, 71. Portulacacee, 70. Portulaca Family, 70. Potato, 200. Potentilla, 114. Prairie Apple, 128. Prairie Fire, 205. Prickly Ash, 133. Prickly Pear, 154. Primrose, 172. Primrose Family, 171. Primula, 172. Primulacee, 171. Prince’s Pine, 165. ‘Privet, 177. Prunus, 116, 117. Psoralea, 126. Ptelea, 134. Puccoon, 191. Pudding-berry, 163. Pulse Family, 117-119. Purslane, 71. Purslane Family, 70. Pyrola, 165. Pyrolacee, 164. Pyrola Family, 164. Pyrrhopappus, 236. Pyrus, 108, 109. Quaker Ladies, 213. Quaking Asp, 47. Quamoclit, 184. Quercus, 56-59. Quince, 108. Radish, Wild, 96. Ragweed, 232. Ranunculacee, 77, 78. Ranunculus, 82, 83. Raphanus, 96. Raspberry, 111, 112. 254 FOUNDATIONS OF BOTANY Rattan-vine, 144. Rattlebox, 74. Rattlesnake Master, 159. Rattlesnake Weed, 235. Redbud, 120. Red Cedar, 19. Red Root, 145. Reseda, 100. Resedacez, 100. Rhamnaceex, 143. Rhamnus, 144. Rhododendron, 167. Rhus, 137, 138. Ribes, 104. Ribgrass, 212. Robinia, 127. Robin-runaway, 195. Robin’s Plantain, 229. Rocky Mountain Bee Plant, 100. Rosa, 115, 116. Rosacez, 105-107. Rose, 115. Rose Family, 105-107. Rosemary, 168. Rowan Tree, 109. Rubiacez, 212, 218. Rubus, 111-118. Rudbeckia, 230. Rue Anemone, 82. Rue Family, 138. Ruellia, 210. Rumex, 66, 67. Rush Family, 29. Rutacez, 133. Rutland Beauty, 183. Sage, 198. Sagittaria, 21, 22. Salicaces, 47. Salix, 48. Salsify, Salvia, 197, 198. Sambucus, 215, 216. Sandalwood Family, 64. Sand Bur, 200. Sanguinaria, 90. Sanicle, 159. Sanicula, 159. Santalacese, 64. Sarracenia, 101. Sarraceniacee, 101. Sarsaparilla, 157, 158. Sassafras, 89. Savin, 19. Saxifraga, 102. Saxifragacer, 101. Saxifrage, 102. Saxifrage Family, 101. Schrankia, 120. Scilla, 36. Scleranthus, 73. Scrophulariacez, 201, 202. Scutellaria, 194, 195. Sedge Family, 23. Self-heal, 196. Senecio, 232. Sensitive Brier, 120, Sensitive Rose, 120. Service Berry, 110. Shad Bush, 110. Shame Vine, 120. Sheep-lice, 189. Sheep Sorrel, 66. Shellbark, .51. Shepherd’s Purse, 98. Sheriff Pink, 281. Shin-leaf, 165. Shooting Star, 172. Shrub, 88. Sickle Pod, 98. Sicyos, 222. Side-saddle Flower, 101. Silene, 78, 74. Sisymbrium, 95. Sisyrinchium, 46. Skullcap, 194, 195. Skunk Cabbage, 25. Smilacez, 31. Smilacina, 38. Smilax, 41, 42. Snakeroot, 135. Snakeroot, Black, 159. Snakeroot, Samson’s, 126. Snapdragon, 203. Snappers, 74. Snapweed, 148. Sneezeweed, 230. Snowball, 216. * Snowberry, 217. Solanacez, 198. Solanum, 199, 200. Solomon’s Seal, 39, 40. Sonchus, 237. Sorrel, Sheep, 66. Spanish Dagger, 38. Spatter-dock, 77. Spearwort, 83. Specularia, 223, 224. Speedwell, 205. Spice Bush, 88, 89. Spiderwort, 27. Spiderwort Family, 26. Spikenard, False, 38. Spinach, 68. Spinacia, 68. Spiranthes, 46. Spirea, 107, 108. Spring Beauty, 70, 81. Spruce, 16, 17. Spurge, 136, 137. Spurge Family, 1385. Spurge Nettle, 137. Squash, 222. INDEX 255 Squawroot, 41, 208. Squaw Vine, 214. Squill, 36. Squirrel Corn, 92. Stachys, 197. Staff-tree Family, 139. Stagger-bush, 168. Staphylea, 140. Staphyleacez, 140. Star-flower, 173. Star-grass, 43. Star of Bethlehem, 37. Steironema, 173. Stellaria, 72. Stick-tights, 189. Stitchwort, 72. St. Johnswort, 149. St. Johnswort Family, 148. Stock, 99. Strawberry, 118. Strawberry Bush, 88, 140. Straw Lilies, 33. Streptopus, 39. Sugar Pear, 110. Sugar Plum, 110. Sumach, 137, 188. Sumach Family, 137. Sundrops, 156. Supple Jack, 144. Sweet Alyssum, 99. Sweet Bay, 86. Sweetbrier, 116. Sweet Cicely, 160. Sweet Clover, 124. Sweet Fern, 49. Sweet Flag, 25. Sweet Potato, 184. Sweet-scented Shrub, 88. Sweet William, 75. Sycamore, 105. Sycamore Family, 105. 256 FOUNDATIONS OF BOTANY Symphoricarpus, 217. Symplocarpus, 25. Syringa, 103, 176. Tamarack, 18. Tangleberry, 170. Tansy Mustard, 95. Taraxacum, 235, 236. Tassel Tree, 148. Taxodium, 18. Tecoma, 207. Thalictrum, 84. Thaspium, 161. Thistle, 233, 237. Thorn, 110. Thuya, 18, 19. Thyme, 198. Thymus, 198. Tiarella, 102. Tickseed, 229, 230. Tilia, 147. Tiliacesw, 146, 147. Tinker-weed, 218. Tipsin, 126. Toad-fiax, 64. Toad-flax, Wild, 203. Tomato, 200. Tongue-grass, 94. Toothache-tree, 133. Toothwort, 97. Tradescantia, 27. Trailing Arbutus, 169. Trefoil, Marsh, 178. Trientalis, 172, 173. Trifolium, 125. Trillium, 40, 41. Triosteum, 218. Tropaeolacex, 132. Tropxolum, 132. Tropzolum Family, 132. Trumpet Creeper, 207. Trumpet Flower, 207. Tsuga, 17. Tubuliflore2, 227, 228. Tulip, 36. Tulipa, 36. Tulip Tree, 87. Tupelo, 164. Turkey Pea, 160. Twin-flower, 218. Two-eye Berry, 214. EY pha, 20. Typhacez, 20. Ulmacee, 59. Ulmus, 59, 60. Umbellifere, 158. Umbrella Tree, 86. Unicorn-root, 32. Urtica, 63. Urticacex, 62, 63. Utricularia, 209, 210. Uvularia, 33. Vaccinium, 170, 171. Valerian, 220. Valeriana, 220. Valerianaceze, 220. Valerianella, 221. Valerian Family, 220. Veratrum, 32. Verbascum, 202. Verbena, 192, 193. Verbenacex, 192. Verbena Family, 192. Veronica, 204, 205. Vervain, 192. Vetch, 128, 129. Viburnum, 216, 217. Vicia, 128. Vinca, 179. Vine Family, 145. Viola, 149, 150, 151. Violacezx, 149. Violet, 150, 151. Violet Family, 149. Virginia ‘Creeper, 146. Virginia Dayflower, 27. Vitacez, 145. Vitis, 145, 146. Wafer Ash, 134. Wahoo, 140. Wait-a-bit, 42. Wake-robin, 40, 41. Waldsteinia, 113. Walnut, 50. Walnut Family, 49, 50. Wandering Jew, 28. Water Chinquapin, 76. Watercress, 96. Waterleaf Family, 187. Water-lily, 76. Water-lily Family, 75. Water Plantain, 21. Water-plantain Family, 21. Water Willow, 211. Waxberry, 49. Wax Plant, 183. Wax-work, 139. Weigela, 220. White Hellebore, 32. White Poplar, 87. White Water-lily, 76. Whiteweed, 231. Whitewood, 87, 147. Whitlavia, 188. Wickakee, 205. INDEX 257 Wild Coffee, 218. Wild Flax, 203. Wild Ginger, 65. Wild Hyacinth, 37, 92. Wild Licorice, 215. Wild Lily-of-the-valley, 39. Wild Oats, 33. Wild Pear, 110. Wild Pink, 74. Wild Potato Vine, 185. Wild Raddish, 96. Wild Sweet William, 186. Willow, 48. Willow Family, 47. Wind-flower, 81. Winterberry, 139. Wintergreen, 165, 173. Wistaria, 127. Witch-hobble, 216. Withe-rod, 217. Woodbine, 146. Wood-sorrel, 131. Wood-sorrel Family, 131. Yarrow, 281. Yellow Flag, 46. Yellow Pond Lily, 77. Yel.ow Sweet Clover, 124. Yellowwood, 121. Yucca, 37, 38. Xanthoxylum, 133. Zebrina, 28. Zephyranthes, 42, 48. Zizia, 161.