- •;• 99 'ANVdlMCO NV1TIHDVH 3HX 019 qijAY 'VIM 'N^LLOJ -3 -j\[ Xq psitpg PUB •9qtus(.iB^[ 'HD:iviaoK>i -g 'NQ Xq iSunj gqj jo uotstA3>j B •aa§Bquadcr) jo A^ISISAIUQ aq; ut XUB}On svi: ).io([ A'C[ •(9E}EinoS9ip.iv) snj9^ pu^ sgssom jo ;u9uidoi9Aaa pu^ 9in;onj;s 9tIX--'('H 'a) TISadKIVO •09*1$ 'OAg uA\oa3 'suoqBaisn^j qi}A\. -Au^og JO s;u9ui9ia-- (-&) MIAVHVa •09-1$ 'H '3 Pu^ *'S'H'3 ''VIM 'NIAVSVQ -j[ Xg jo ASoiOTsXqd iHDiprjd — 'MOXOV *H '3 P™? (-3) MIA\HVQ °S^U90 06 '00191 'A\O§ {;) JO XlISJ9AIUf) 3qi lit XllB^OCJ JO JOSS9JOJJ Sm§3>J ''S'>I'3 ''DS'Q '3 X'a 'SjanmSag JGJ XuT6;og FK>TPBI, ol i OUrse, l>c. ause the teachers are not trained in scientific drawiiv. SCIENTIFIC DRAWING AND DESCRIPTION 69 talents of individuals should receive the greatest encouragement and stimulation, and if some can accurately shade so as to make their diagram a good picture, so much the better. But at first the drawings must be, above everything, clear accurate diagrams of the actual structure. . To this end every line and spot in them should represent something in the object, and no spot nor line allowed to the equivalent of which in the object the student cannot point. Moreover, outlines should be complete, and no loose ends, nor hazy joinings, nor dim angles, should be permitted. Such imperfections generally correspond to loose, hazy, or dim ideas, which it is one of the chief uses of the drawing to remove and to replace by clear and sharp conceptions. It is for this reason the generalized dia- grams, to be spoken of later, are of such great value. I have found that "rough drawings," sometimes recom- mended, are of very little use, and the impressionist kinds, often really beautiful, made under teachers untrained in scientific methods, are little better. The true diagrammatic drawing takes but little if any more time, and is many times more valuable. Indeed, a mere " drawing ' of an object, i.e. a representation of its appearance to the eye, a reproduction of the impression the object makes upon the beholder, has very little if any scientific value in connection with laboratory work, and is not worth the time it takes. Such drawings are in place in a drawing class, and 70 THE TEACHING BOTANIST even in certain phases of general natural history study; but they reflect not at all the clearly cut ideas which should characterize the activities of the laboratory. Samples of clear diagrammatic drawings may be seen later in this work (Figs. 12, 13, 14). Practically, the best way to make these freehand drawings is first to outline them very faintly in pencil, and then alter this outline until it corresponds to that of the object, after which a single, firm, complete, even line can be run over it, and all the lighter lines erased. All mechanical helps, such as rulers, compasses, etc., should be allowed when they contribute to accuracy. An important principle in making the drawings to illustrate the structure of an object is economy of number ; as many drawings should be made as are necessary fully to illustrate the object, and no more. Thus, for a seed like the bean (Fig. 12), two draw- ings are sufficient ; an end view would bring out little if anything not already in the other two. One view of an object need not duplicate what is already in another, though different views of the same feature should always be included. The extreme aspects of an object should be chosen for representation, i.e. a face or edge view should be an exact face or edge, and not a quartering view. Of course, different draw- ings of the same object should be perfectly consistent as to size, form, etc. The scale of the drawing in comparison with the SCIENTIFIC DRAWING AND DESCRIPTION original object is very important, and should always be expressed. This is usually done in good monographs by a fraction ; if the drawing is one-half the size of the original, the fraction ^ should be placed beside the drawing ; if the drawing is twice the size of the origi- nal object, it is expressed by ^ ; if the same size, by ^, and so forth. The best general rule as to scale is to make the drawing as small as will allow all features intended to be represented to be clearly seen. If, however, making clear certain of the smallest features would make the entire outline very large, it is better to make two drawings, one showing the details only upon a larger scale. It is well to give the students small pasteboard rulers, preferably on the metric sys- tem, which can be kept in pockets in the back of the laboratory books, and used for making the scale of the drawings correct. The different features of the drawings should be carefully labelled to show their names. The exact spots to which the names apply should be shown by fine ruled dotted lines, as in Figs. 12, 13, 14. In books, for appearance' sake, usually only letters are thus attached to the drawings, and the corresponding names are given in an explanation below or in the text. But in laboratory work I have found that the extra neatness of this plan does not compensate for the loss of time required of the teacher to look up the explanations, and I think it much better to 72 THE TEACHING BOTANIST label the drawings with the names directly, as shown in Figs. 12, 13, 14, where the whole subject is visible at one glance. For this labelling a compact vertical writing, or even printing, is desirable, and should be cultivated when wanting, and a compact writing is pleasing, too, for the notes. When one set of words can be applied to two or more drawings, as in Figs. 12, 13, 14, it is an advantage, but of course is not essential. Where drawings do not fully explain them- selves, they should also be labelled beneath by de- scriptive words, such as " face view," " transverse section," etc. Different drawings of the same object, unless their connection is perfectly obvious, should be kept in correlation with one another by proper cross-references. Of course neatness and artistic effect are desirable qualities in all work, and some attention may be given to placing the drawings well on the page, away from the margin, with the long axis upright, and to leaving plenty of room between different ones of the same object, and between differ- ent topics, etc. In all of these respects, i.e. completeness and clear- ness of outline, economy in number, scale, labelling, neatness, it is pedagogically a very good principle to let the students at first do the best they can unaided. After they have done their very best, they are in a posi- tion to fully understand and profit by the teacher's hints as to how they may do still better. Instruction on SCIENTIFIC DRAWING AND DESCRIPTION 73 these points after their own efforts have made them feel the difficulties has many times more meaning than it has before they have themselves tried. It is impor- tant, however, not to confuse them by too many suggestions at once. It is much better to point out improvements in but one or two respects at a time, and thus come gradually up to a high standard. The earlier drawings will on this plan be incomplete, and they may subsequently be brought up to the higher grade, or left as a record of progress, not without its value. From the first, it is necessary to insist that the laboratory work shall not be made a drawing lesson. The laboratory hours are for observation and com- parison, and time for outline drawings only can be taken ; all refinements should be added outside of these hours. Drawing with the microscope, after the use of the instrument is once learned, offers few difficulties, since the objects are seen in but one plane. In drawing tissues, it is a good plan to shade all walls, and leave intercellular spaces and cavities blank, even in cases where, as in cross-sections of bast fibres, the re'verse would make a better picture of the object. Here, also, diagrammatic clearness is the highest quality of the drawing. After the first principles of scientific drawing as here outlined have been grasped by the student, the teacher may well give from time to time some instruction upon 74 THE TEACHING BOTANIST the simple use of shading, etc. In this the teacher, as well as students, will gain great profit by a study of good models, where shading has been very effectively used, as in the best figures in their text and reference books. A particularly splendid model is to be found in the illustrations to Sargent's " Silva of North America," where drawings of seeds, twigs, leaves, etc., such as are taken up in the laboratory, may be found. Kny's series of wall diagrams also offer excellent models. It is a good plan also to have students copy at times into their note- books good diagrams from the Kny series, or from good books, especially where an important topic is being studied with poor material. A drawing copied from a good source is a better record of an important topic than no drawing at all, though of course this must be resorted to but rarely, and then only after assurance of a perfect understanding of the diagram by the student. Drawings will ordinarily be made in lead pencil (Faber HHHH (4H) I have found best), but there are many advantages in finishing them in India ink. The drawings may thus be saved from rubbing through hand- ling of the books, are more permanent, clearer, and of better appearance generally. Liquid India ink and fine mapping pens should be used. Shading can be given either by fine dots made more numerous for a deeper shading, or by very fine lines also made more numerous for a deeper shading, or even given by pencil with an ink outline. With my own students the use of the ink SCIENTIFIC DRAWING AND DESCRIPTION 75 is made voluntary, and most of this work must be done outside of the laboratory ; but almost invariably the best students, after they have once tried it, take to its use altogether. The improvement made by use of the ink tends greatly to foster the very desirable pride of students in the appearance of their books or notes. Of course the outlining must first be done in pencil, the marks being erased after the ink has been added. Every encouragement should be given to individual artistic tastes in drawing, even to the point of allowing some use of color. But it is constantly necessary to guard against the eclipse of the naturalist by the artist, and the beautiful drawings must be allowed to be no less accurate than those which are merely diagrammatic. Students should be encouraged to work in physical comfort and with a feeling of leisure, with indepen- dence yet readiness to profit by the excellences of their neighbors. It is well to allow the poorer students frequently to see the drawings and notes of the better ones. For the drawings a good smooth paper, which will take both pencil and ink, is necessary. It should never have a perfectly smooth nor glossy surface, nor yet be rough like that used for sketches by artists. The kind called ledger paper is very good. There are different methods of keeping the drawings, one of the commonest being to make them on separate sheets of drawing card- board of uniform size (usually 6x4 inches) which are 76 HIE TEACHING BOTANIST then kept in a simple cover. For advanced students this does very well, but is less excellent for beginners. It is very difficult to keep notes and drawings together in this way, and it allows of easy loss and constant disarrangement. After trial of many systems I have concluded that a book is best, and have invented a special laboratory book which I have used for three years to my great satisfaction. It is made of the best quality of ledger paper 8^ x 6| inches, ruled on the right hand page for notes and unruled on the left hand for drawings, and is strongly bound in linen. It is made by the Cambridge Botanical Supply Company, and a sample is sent by them to teachers. Experience shows that a thoroughly good book of this kind pays in many ways, and particularly in the increased care students give to the neatness and completeness of their work. There is one kind of drawing of which the value grows upon me year after year, namely, the generalized mor- phological diagrams worked out in colors, often called for in the Outlines in Part II of this book. (See partic- ularly Figs. 15, 28, and their explanations.) To work them out correctly necessitates the greatest clearness of" ideas, and inculcates comparison and generalization of the highest value. Indeed, such diagrams demand thinking of mathematical exactness and clearness. The coloring to show morphologically identical structures can he added by water-colors, or by pencils which may be Ix night in small boxes containing six colors. SCIENTIFIC DRAWING AND DESCRIPTION Supplementary to the drawings, and necessary to cor- relate these, and to bring out features which they do not, are the notes or descriptions. These should be as con- densed as possible, both for the effect upon the student's composition and also for the convenience of the teacher who has to examine them. They should not contain anything that can be clearly shown in the drawings. They should usually be complete sentences, and perfect in their English, terse and expressive. Whenever pos- sible they should be thrown into tabular form. Draw- ings and notes should of course be mutually intelligible and consistent, which is the more easy if abundant cross-references are used. The two are much more effective if kept opposite one another, as they may be in such a book as has been recommended. Of great importance for review, for generalization, and for securing correctness of proportion are synoptical essays, which should be called for under each topic as soon as it is completed. These essays should be strictly limited in length, yet required to include all phases of the subject of any importance; thus is conciseness and directness cultivated. It would probably be found advantageous to make arrangements whereby these essays could also count as work in English composition. It is not at all intended that the essay shall simply repeat what is already carefully recorded in the labora- tory books ; it is rather a comprehensive but synoptical outline of the entire subject based upon all sources 78 THE TEACHING BOTANIST of information,- -laboratory work, reading, lectures. It is primarily a study in proportion and in correlation. After the students have done their best with their first essay, it is well for the teacher to read them a selected one or even one composed by himself ; and to illustrate this point there is given in Part II, Section 3, one that I have read to my own students after they have completed the study of the seed as called for in the first three Sec- tions of the Outlines. Practically, I have found it most advantageous to have separate books, uniform with the laboratory books, for the essays ; the latter are, of course, corrected and returned to the writers. V. ON LABORATORIES AND THEIR EQUIPMENT BOTANICAL laboratories are of many sorts, from those built especially for the purpose by some of the greater universities down to unaltered schoolrooms ; but all have this in common, that the room and its furniture are of far less account than the person who directs them. In other words, it is more profitable to give a good teacher to a poor laboratory than a good laboratory to a poor teacher. Laboratories, like methods, are fine tools for skilled workmen, and they give but indifferent results in the hands of those untrained in their use. Proper laboratories every teacher should strive for; but he is not to suppose that good work must be put off until he achieves them. Many universities, some colleges, and a few high schools now possess good botanical laboratories, and if a teacher has the opportunity to direct the building of a new one, he should visit some of these and ask advice of their directors. He may obtain their addresses by writing to the Professor of Botany in the principal university of his State. But the following points will also be of use : - First, of course, is the room, in which a prime requi- site is abundant light. This implies many and very tall 79 So THE TEACHING BOTANIST windows, which, if all in one wall, should preferably face the north in order to avoid exposure to direct sunlight ; but this point is really of no great consequence, since thick white shades perfectly temper the direct sun, and ! M G.T W SCALE OP rEElT I I I 20 10 8 6 4 FIG. i. — Plan for a square laboratory, lighted on two adjacent sides. C, case for museum specimens; G. T., gas and tool table; L, lockers for students' effects, etc.; Af, tabks for materials, etc.; P, teacher's platform, with black- board; A', sink; IV, Wardian case. in short winter days it is an advantage to have the win- dows face in the lightest direction. The walls should be LABORATORIES AND THEIR EQUIPMENT 8l tinted white or nearly so, and the furniture made of light- colored wood. Floors should be solid and dust kept out as far as possible. Unless the windows are very large it is best to use but one row of tables, of which, for elementary work, the most efficient and economical dis- tribution known to me is that shown in the accompany- ing figures (Figs, i, 2). Each table stands opposite a W G.T. ,,,,,, SCALE Of FEET 0 12 3 i5 G 8 10, 15 FlG. 2. — Plan for an oblong laboratory, lighted on a long and a short side. Lettering as in Fig. I. window, and is used by five students (or three if room allows), two on a side and one at the end. Rooms are often of square shape and lighted from two adjacent sides, in which case the arrangement shown in Fig. i is good. For a long room the most economical arrangement is that shown in Fig. 2. Where more than one row of tables must be used, it is best to place them in a second row, each exactly in line with one in the first and four feet from it. The tables may be perfectly plain, of 82 THE TEACHING BOTANIST whitewood or pine, each on four solid legs, oiled but not varnished on top, thirty inches high (lower for schools), and eight feet long by three feet wide.1 It is well to have black lines ruled to mark off the territory for which each of the five students is to be held responsible. Plain chairs with rubber caps on the feet are good, though revolving chairs have advantages. At least four feet should be left between each table to allow each student abundant room, and to permit the teacher to pass easily among them. Shallow drawers may be made in the tables, but if many divisions of students use the same tables, these will be insufficient and may as well be omitted in favor of lockers and drawers built elsewhere in the room in sufficient number to allow one to each student. For elementary students a drawer eighteen by twelve inches is ample, but each student should have one to himself for his tools, note-books, etc. Stone jars under each table for waste materials are desirable. Of other furniture, I would place next a Wardian case, or miniature greenhouse, in which plants may be kept alive while under observation or experiment. In fact, not much physiological work is possible without something of this kind, for the dryness, gases, and other disturbances of an open schoolroom produce abnormal results, and often no results at all. The 1 In-tailed descriptions and figures of various forms of laboratory tables may be found in the Journal ,>/ Applied Microscopy (Rochester, N.Y.), for April, 1899. LABORATORIES AND THEIR EQUIPMENT 83 ideal place for this work is a small greenhouse open- ing off the laboratory ; and often some angle or gable of the building offers a place for it. In such a house not only could experiments and observations extending over a considerable time be carried on, but a small collection of typical plants to illustrate ecological prin- ciples could be kept to obvious advantage. In place of this, where very large, especially bow, windows are available, a glass partition could be used to make a small greenhouse in the laboratory ; but the heating might offer difficulty.1 But a simple Wardian case is always a possibility either in laboratory or schoolroom. Its chief qualities are abundant light, hence as much glass and as little frame as possible, sufficient tightness of construction to hold moisture and exclude most of the gases and dust of the room, and some provision for heating in case the temperature of the room falls below about 10° C. at night, or when high temperatures are needed for special experiments. Such a case,2 built entirely of glass and metal, in use in my own labora- tory, is shown in outline in Fig. 3. The floor is a copper box four inches deep filled with water and heated from below by a Koch safety gas burner, whose flame is shielded from draughts by a sheet-iron hood. The 1 Valuable hints upon the management of such window gardens, and suggestions as to the best plants for them, are given by J. W. Harshberger in Education, XVIII, 1898. 2 Made for me by Williams, Brown, and Earle, of Philadelphia. 84 THE TEACHING BOTANIST height of the flame is controlled by a Reichert thermo- regulator inside the case, which can be set at any de- sired point, and which keeps the temperature within 3° C. of that point, no matter how low it falls in the room outside. This case is, however, more elab- orate than necessary, and, after my expe- rience with it, I believe one would work well if built in the follow- ing manner. Have made a covered, gal- vanized-iron box the length of the window, two feet wide and three inches deep, with a hole in one corner for filling, and a tight sheet - iron hood be- neath to shield the flame and keep gases Fi<:. 3. — A successful Wardian case. Scale, from rising through ^ inch = i foot. the joints of the case; have sashes made with as little wood as possible to surround and cover it, as shown LABORATORIES AND THEIR EQUIPMENT 85 in the cross-section in Fig. 4; on one of the long sides two doors must be left, which can be tightly closed; the top may be hinged to allow opening for ventilation at times ; support the whole on a firm table ; shelves of glass or wire net- ting may be added; use preferably a Koch safety burner (which shuts off the gas if the flame goes out) and a Reichert regula- tor. The entire cost should not exceed $25 to $30. It should not be built into the window, at all events not without an extra sash some in- ches from the win- dow sash. SCALE IN INCHES 18 Other npre^arv nr FlG> 4- — Plan for a Wardian case, in cross- saiT section. H, sheet-iron hood; //, hinge of desirable furniture is top; W.B., water box of galvanized "iron; dotted lines show legs of table. 86 THE TEACHING BOTANIST the following. There should be one or two large tables for holding the supply of material for the class and for demonstration, etc. These may be built three feet high, with lockers for microscopes, or other storage, beneath. A teacher's platform with a blackboard is essential, and over it, as well as elsewhere in the room, should be racks for displaying diagrams. The best racks I know of are boards an inch thick, four inches wide, B A and ten feet long, rounded on one edge to hold Den- nison's No. 12 Card P Holders (which are far the best dia- gram holders I have ever seen) ; these boards D run FIG. 5. — A successful rack for displaying jn a lio-flt diagrams. A, B, pulleys ; C, cleat for fastening cords ; D, cross-section of the frame, like a WH1- guiding-case, enlarged. i r , i dow frame, and are raised and lowered by cords attached as shown in Fig. 5, which also shows a cross-section of the guiding- case. The latter, however, is not indispensable. Two boards may be used in the same case, passing one another and giving two tiers of diagrams if the ceil- ing is high enough either above the blackboard, or elsewhere. A gas table for heating, glass-bending, etc., is necessary, as is a large sink (preferably porcelain- LABORATORIES AND THEIR EQUIPMENT lined) with several taps, and cases with glass fronts for storing museum specimens, materials, etc. Lockers or drawer cases, when built away from the wall (as in Fig. i), should not be over four feet high, in order not to obstruct a free view around the room.1 Of instruments the first in importance are the scal- pel, two needles in handles, forceps, and hand lens, which should be supplied as a loan to each student, together with a box to keep them in. These may FIG. 6. — A successful set of dissecting instruments, with case. be bought in various forms and qualities at prices from 75 cents upward per set from any of the firms mentioned later. For use with my own classes I have designed the set, together with their leatherette case, figured herewith (Fig. 6), which is manufactured for me at $1.20 each by Williams, Brown, and Earle, of Philadelphia, and which has proved very satisfactory. It includes all instruments essential in elementary work. 1 There are valuable hints upon these points, and upon other matters connected with laboratories, in a fully illustrated article on " Repre- sentative American Laboratories," in the Journal of Applied Microscopy (Rochester, N.Y.), Vol. I, 1898, pp. 22-32. 88 . THE TEACHING BOTANIST The lens fits in at one end and the needles, etc., at the other ; and the case is intended either for keeping the tools at the laboratory or for carrying them in the field. A fair dissecting microscope may be made by placing the lens open on the case, with the lenses, held in position by one of the flaps, projecting over the side. Next in importance are dissecting microscopes, which are of the greatest value. There should be at least one to a seat, preferably one to a student. There is a large variety of these by different makers, and of great range of excellence and cost. For a cheaper kind, the Barnes Dissecting Microscope offered by Bausch and Lomb to schools and colleges at $1.88 to $2.82 is excellent, and, in my opinion, ample for ele- mentary courses. The compound microscope is the chief tool of the biologist and indispensable to the biological laboratory. The ideal arrangement provides one for each student ; after that, one to each seat where more than one division uses a room ; after that, one to as few stu- dents as possible. If there is one to each student, it is easy to hold him responsible for its condition ; and its life is so much longer that it pays in the end to provide the greater number at the start. There are all grades of compound microscopes and all prices. The makers best known in this country are Zeiss, of Jena (Germany), Leitz, of Wetzlar (Germany), Reichert, of Vienna (Austria), and Bausch and Lomb, of Roches- LABORATORIES AND THEIR EQUIPMENT ter (New York). After much experiment with many makes, I have, for the use of my own classes, fixed upon the instrument shown in the accompanying cut (Fig. 7), which has been specially made by Reichert, and is supplied, duty free, at $27, by Richards and FlG. 7. — A successful student's microscope. Company, of New York. Its points of excellence are, — the very firm base, the presence of a nose- piece (a most valuable time-saver), and a case in which it can be kept without closing the tubes. It has objectives 3 and 7 and oculars II and IV. It is THE TEACHING BOTANIST nearer the ideal student's microscope than any other that I know of. If a less expensive one is necessary, the nose-piece can be omitted, and there are other stands and combinations by the same maker. Instru- ments of corresponding power are supplied by other makers. Those of Zeiss are usually considered the best of all, but they are also most expensive. Those of Leitz are thought by many to offer a good resultant between cost and quality. All foreign makes of micro- scopes and other instruments may be imported by col- leges and schools free of duty, and to meet this the chief American firm, Bausch and Lomb, offer special discounts from their list prices to those institutions. It does not pay to buy a cheap microscope, and nothing less than a firm stand of the continental pat- tern, with two objectives, two-thirds and one-sixth inch focus, and two eye-pieces, should be accepted, and a nose-piece is well worth its cost. For such an instrument $20 or more must be paid. It is better to have a few of this grade than more of a poorer sort, and in buying from any other than the firms of recognized worth, it is better to seek the advice of some specialist. In the laboratory the mi- croscopes should be kept in lockers, especially if there is one to each student, or they may be kept on the laboratory tables under glass bell-jars, or even in their cases when there is but one to a seat. Like other laboratory apparatus, they should be loaned for LABORATORIES AND THEIR EQUIPMENT the term to the students, who should be held fully responsible for their good condition. In an elementary course few reagents are used, and these so rarely that it is better to place them on the tables only when needed. The best reagent bottles known to me are those in which a pipette forms the ground glass stopper, as shown in the accompanying figure (Fig. 8). These bottles and other dishes and miscella- neous glassware are happily in- expensive, and may be obtained from any of the firms dealing in chemical supplies. Apparatus for physiological experiments must partly be made to order from directions given in books, and partly bought ; and most of the needed supplies may be purchased from the firms mentioned below. Most of the articles are not used up, but once obtained are valuable year after year. There is no firm known to me which makes a specialty of apparatus for plant physiology, though no doubt, in view of the rapidly increasing attention given to this subject, that lack will soon be supplied ; and it will not be long before FlG. 8. — An excellent form of reagent bottle. 92 THE TEACHING BOTANIST the apparatus necessary for a standard set of physio- logical experiments for an elementary course in Botany will be offered for sale at a fair cost, precisely as such apparatus is now offered for the Harvard Entrance Requirement in Physics. Abundant materials in proper condition are a ne- cessity for good study, and fortunately these are not expensive. They are partly to be bought in the markets or from greenhouses, partly collected the summer before, while, as a last resort, some of the more special materials may be bought from a botanical supply company. If the teacher has at command his own greenhouse and gardener, as many colleges have, he is fortunate. If he is near a bo- tanic garden, he will find the director ready to aid him in anything which advances botanical knowledge. Commercial greenhouses, happily, are everywhere, and the teacher should make friends, and a bargain in advance, with the gardener for such materials as he needs, — bulbs, flowers, leaves, plants for experi- ment, and also for keeping certain illustrative water plants, etc. All this, together with many other incidental expenses about a laboratory, necessitates some regular income. In colleges this is generally supplied by the laboratory fee paid by the students, amounting on an average annually to about $5 for each student, which is ample. Since the public school system does not allow of such a source of LABORATORIES AND THEIR EQUIPMENT 93 revenue, its place must be taken by annual grants from the school committees, and the teacher should insist upon that sum or as near it as possible. The materials to be collected in summer (unless for the herbarium) are best preserved in glass preserve jars in water to which two per cent of formaline (also called formaldehyd and formalose) has been added ; this will perfectly preserve all vegetable tissues, but since its fumes irritate the eyes and throat, the materials should be well washed in water just before they are used. It is well in the spring to go through the out- lines for the next year's work and list the mate- rials needed, as a guide for the summer collecting. Pressed flowers are sometimes recommended for study, but they are difficult for and repellent to the beginner, who should have fresh ones only. The charts, museum specimens, and other desirable illustrative parts of a laboratory equipment are dis- cussed in the next chapter (Chapter VI). The only firm in the United States which professes to deal exclusively in botanical supplies, and as well to supply everything needed by botanists, is the Cam- bridge Botanical Supply Company, of Cambridge, Mass. A new firm, the Ithaca Botanical Supply Company, Ithaca, N.Y., has lately been organized. The Knott Scientific Apparatus Company, of Boston, Williams, Brown, and Earle, of Philadelphia, Richard Kny and Company, of New York, all deal in smaller 94 THE TEACHING BOTANIST botanical supplies, and the names of other firms else- where may be found in the advertising pages of the Botanical Gazette. For larger glassware of all sorts, Eimer and Amend, of New York, and Richards and Company, of New York, are the firms I know best, but all large dealers in chemical supplies keep such apparatus. If a large quantity is wanted, it pays to import it duty free through some of these firms, in which case orders must be placed two or three months in advance, but this is not worth while for very small orders. VI. ON BOTANICAL COLLECTIONS AND OTHER ILLUSTRATIONS THE only true foundation for biological knowledge is laboratory or other practical study. This method, how- ever, has an inherent defect in that, consisting as it must in the investigation of more or less isolated topics or types, the view it gives of the plant world is discon- tinuous and poor in perspective. To realize the full value of the study, these types need to be correlated and located in the general system, thus contributing to the formation of one complete and correct conception. To this end, reading, lectures, and other formal instruc- tion are of great aid, and these I have treated elsewhere in this work ; but equally valuable is that comprehen- sive survey of a large series of forms which is made possible only by collections of living plants, of museum specimens, of photographs or charts, of models, etc. The study of these collections alone would have little meaning, but every type thoroughly studied in the laboratory becomes a centre of illumination for a zone of related topics, which have a vivid significance and interest entirely lacking without such study. By far the most valuable of all botanical illustrations 95 96 THE TEACHING BOTANIST are living plants growing untouched in their native homes. But practically the use of these* is very limited, for some of the most instructive are tropical or of other lands, and the native ones are not only often distant, especially from students in cities, but in our climate are unavailable for most of the school year. These draw- backs are partially overcome by botanic gardens, which not only bring plants together from the uttermost parts of the earth, but group them in a manner which is itself instructive. Plants in gardens, however, while valuable for investigations upon structure and classification, are nearly valueless for studies upon their natural relations to their surroundings, though they may be so grouped as to form valuable illustrations of some well-known principles of ecology. The teacher who is so fortunate as to be within reach of a botanic garden should make the acquaintance of the director and obtain permission for himself and his students to use it freely, which will usually be readily granted. Botanic gardens are very numerous in Europe, but rarer in this country ; the principal ones of North America are the following, arranged in order from east to west : — The Arnold Arboretum (a department of Harvard University), at Jamaica Plain, Mass. The Botanic Garden of Harvard University, at Cam- bridge, Mass. The Botanic Garden of Smith College, at North- ampton, Mass. BOTANICAL COLLECTIONS 97 The Botanic Garden of McGill University, at Mont- real, Canada. The New York Botanical Garden, at New York City. The Botanic Garden of the University of Penn- sylvania, at Philadelphia, Pa. The Botanic Gardens of the United States Depart- ment of Agriculture, at Washington, D.C. The Buffalo Botanical Garden, at Buffalo, N.Y. The Botanic Garden of the Michigan Agricultural College, near Ann Arbor, Mich. The Missouri Botanical Garden, at St. Louis, Mo. The Botanic Garden of the University of California, Berkeley, Cal. There are others also, but of less complete organization, in connection with some other colleges, especially some of the State and agricultural colleges. By far the most important of the above list are the Arnold Arboretum, the Missouri and the New York gardens (the latter now forming), next to which comes that of Harvard Univer- sity. The Smith College Garden was especially planned from the start as a teaching garden, and as such is fairly complete.1 School gardens have scarcely at all received attention in this country, but a noteworthy article by 1 A full account of it, with a plan, is contained in Garden and Forest, Vol. X, p. 512, 1897. The New York Garden is described in the three Bulletins of the garden by Dr. N. L. Britton, an important address by whom, on " Botanic Gardens," is in Garden and Forest, Vol. IX, p. 352. The Michigan Agricultural College Garden is described by W. J. Beal in Garden and Forest, Vol. VIII, pp. 303, 322. H 98 THE TEACHING BOTANIST H. L. Clapp, on "School Gardens" in the Popular Science Monthly for February, 1898, gives a description of a remarkably successful garden on the grounds of a Boston school, and shows how much may be done with limited space and means. Such gardens must repay many fold their cost, not only in botanical instruction, but in moral influence, and their formation cannot be too highly commended. There are very practical directions upon this subject in L. H. Bailey's " Lessons with Plants," and especially in his " Garden Making," show- ing how much can be done at little or no expense, and a recent book in German, illustrated with plans,1 is devoted entirely to this subject. An essential feature, indeed the most essential fea- ture, of all botanic gardens are their ranges of green- houses, for thus are the living plants made independent of climate and country. Such collections illustrate extremely well most structural features, and fairly well many ecological principles, especially where the natural conditions are carefully imitated, as is to some extent possible with water plants, desert plants, epiphytes, etc. If the teacher has not the use of such a collection, and has no school greenhouse, he can perhaps make the acquaintance of some owner of a private or even a commercial greenhouse and persuade the owner to accumulate some of the more important forms. What 1 Cronberger, B. " Dor Schulgarten des In- und Auslandes." Frank- furt a. M. 1898. 2.80 marks. BOTANICAL COLLECTIONS 99 these forms are, he will know from his own earlier studies. Next in value to living plants come dead ones pre- served to look as much like life as possible. The collection and arrangement of such specimens is the function of museums. Unhappily, there is no known method of preserving plants in their natural forms and colors as is possible with so many animals ; though on the other hand it is possible to preserve plants, when dried, with cheapness, compactness, and accessibility far exceeding what is possible with animals. Hence it comes about that there are many great herbaria and but few great botanical museums. Even in Europe botani- cal museums are very scarce and of minor interest, and in America there is as yet but a single botanical museum of any account, that of Harvard University, and this one owes its interest chiefly to the success with which the living plants, including flowers, have been imitated by glass models of the most natural form, size, and color.1 In time the New York Botanical Garden will undoubtedly possess a museum of the greatest com- prehensiveness and value. Most colleges with depart- 1 This collection of models is being made by Leopold and Rudolph Blaschka, of Dresden, Germany. It has attracted wide attention for its great accuracy of execution. A full account of it is given by Walter Deane, in the Botanical Gazette, XIX, p. 144. One of the curators of the British Museum has said of it, " No other museum possesses anything half so beautiful." It is unique, and by contract with the makers no part is to be duplicated. IOO THE TEACHING BOTANIST ments of Botany possess small teaching collections, and these are of such value that every teacher of an elementary course should aim to gather at least a small museum. Many parts of plants, such as hard fruits, woody stems, etc., may best be preserved dry, as indeed may the entire plants themselves, in herbaria, of which I shall speak presently. But the softer parts can be kept only in some preservative liquid, though none is known which will keep color well. A solution of three per cent formaline in water will preserve color as well as any, but it keeps some colors much better than others ; and in it the important green tissues become of a translucent unnatural shade, which is hardly worth the having.1 In my own collections I use a mixture of two per cent formaline in thirty per cent alcohol, which preserves the softest tissues perfectly in every respect except color. Formaline is used in such small quanti- ties that it is really very cheap ; and colleges and schools are entitled by law to purchase, though with rather complicated legal formalities, alcohol free of internal revenue tax, which makes it cost only about 40 cents per gallon in quantity. Bottles for speci- mens may be any one of the many forms of preserve jars; but after considerable experience with their effect 1 If one wishes to try to preserve the green color by other methods, he may consult to advantage an article by A. F. Woods, in the Botanical Gazette, XXIV, p. 206. BOTANICAL COLLECTIONS IOI upon classes, I am convinced that it is true economy to buy only the best white flint glass bottles with ground glass stoppers, not only for specimens in liquids, but also for dry objects, such as seeds, which need some kind of a vessel. Thus not only are all specimens safe from evaporation and dust, but the respect of the stu- dent is far greater for a compact, artistically presented specimen than for one in a green leaky jar or a dusty box, and hence its value to him is greater. The teacher, too, is more likely to accumulate only things of value if the receptacles must be economized. For a collection of my own I prefer a dozen such specimens to thrice that number indifferently prepared. I have experimented with several forms of bottles, and finally have fixed upon Whitall and Tatum's (Boston and New York) No. 2605 specimen jars, which may be had in all sizes, and for which their published prices are sub- ject to large discounts. I prefer the appearance of these to that of the kinds without a neck. But of course if one cannot afford such bottles, some of the many forms of preserve jars will do very well, and are far better than nothing at all. In whatever manner prepared, however, every specimen should be in condi- tion to be handled and passed about. Tight, upright, glass-fronted wall cases should be provided for them, and it is well to have them very fully labelled and care- fully arranged upon a definite plan in order that they may be as instructive as possible when not actually in 102 THE TEACHING BOTANIST class use. In any museum collection whatever, the great guiding principle should be selection, not accumu- lation ; and in plan and labelling the famous dictum of Goode 1 should be remembered, that the modern museum is a collection of labels illustrated by speci- mens. The teaching collection need have no formal beginning ; but as specimens from one source and another are obtained, they should be properly pre- pared and added. There are as yet no firms offering for sale considerable numbers of museum specimens of plants such as are offered of animals. It is of the greatest importance, however, that the collection should grow upon some definite plan, as otherwise half of its value is lost. One may, accord- ing to his tastes or facilities, take as the leading idea the illustration of the principles, either of mor- phology, ecology, or the natural groups. An ideally complete collection would include all three. Follow- ing is a suggestion for a plan based upon that which I have worked out for the collections under my charge : — 1 There are valuable papers on Museum-making, by G. Brown Goode in Science, New Series, Vol. II, p. 197, and Vol. Ill, p. 154. Particularly apposite and most valuable, though I cannot agree with all of its recom- mendations, is J. M. Macfarlane's " The Organization of Botanical Museums for Schools, Colleges, and Universities," in Woods IIoll Biological Lectures for 1894. Of much suggestiveness is Boyd Dawkins' address on the Place of Museums, in Nature, July, 1892, p. 280. See also ATature, 1895, P- I07- BOTANICAL COLLECTIONS 1 03 Division I. Morphology. A. Phylogeny of the Plant Kingdom ; progress from thallus to shoot and root ; and from sporangia to ovules and anthers. B. Particular anatomy and morphology of Thallophytes, Bryophytes, and Pteri- dophytes. C. Particular anatomy and morphology of Spermatophytes. 1. The root, typical form and plasticity. 2. The shoot. a. Stem, typical form and plas- ticity. b. Leaf, typical form and plasticity. c. Flower, typical form and plas- ticity. d. Fruit, typical form and plas- ticity. Division II. Ecology. Adaptations connected with particular or typical modes of, — A. Nutrition. a. Absorption. b. Transfer, including transpiration. c. Metabolism, including photosynthe- sis. d. Storage. e. Secretion and excretion. B. Growth. C. Reproduction. D. Irritability, i.e. individual response to ex- ternal stimuli. 104 THE TEACHING BOTANIST E. Locomotion. a. Of pollen. b. Of seeds and some vegetative parts. F. Protection. a. Against weather conditions. b. Against living enemies. Division III. The Natural Groups of Plants. (Natural History of Plants.) A. The Algae. B. The Fungi. C. The Lichens. D. The Bryophytes. E. The Pteridophytes. F. The Sperm atophytes. I. Floristic Divisions. II. Ecological Divisions. Mesophytes. Hydrophytes. Xerophytes. Halophytes. Climbers. Epiphytes. Parasites. Insectivora. Myrmecophila. Etc. Of course this plan is too comprehensive to be carried out in its entirety in a teaching collection, and it is offered but as a suggestion. In a large public museum, other sections, to illustrate palaeontology and economics, would be added, together with the fullest representation BOTANICAL COLLECTIONS 1 05 of all phases of the subject by models, paintings, photo- graphs, apparatus used in investigation, etc. Even in the smallest collection there should be the fullest label- ling, which should give the exact place of the specimen in the plan. As an example, I give here a typical label as adopted for my own collection (Fig. 9). These labels need not be permanently attached to the bottles, but are to be placed with them when not in use by the class, THE BOTANICAL MUSEUM OF SMITH COLLEGE D'm'si'on H . Adaptations . to E. Locomotion . ty , tkroi/yk ayentu oj. Wind, actmj upon Wings. OutgrowtK of 6eed-Coat an. w inqei Seeds d Tecoma. radt'cans FlG. 9. — Sample museum label. though a briefer label should also be kept in each bottle. It is well to have the museum specimens always visible and accessible. Theoretically, an herbarium is a part of a botanical museum, but on account of its special nature and use it is kept stored by itself and not on exhibition, though sometimes a few pressed plants are exhibited behind IO6 THE TEACHING BOTANIST glass, like pictures. For investigation into and illustra- tion of systematic Botany, an herbarium is absolutely indispensable ; but in a teaching collection, for use where the work is not primarily systematic, the plan of the collection should accord with the plan of the teaching. The question now arises whether it is not possible to utilize the great ease, cheapness, and compactness of the herbarium method of preservation of plants in the formation of a collection to illustrate the principles of morphology, ecology, and natural history. I have experi- mented not a little upon this subject to the conclusion that an herbarium of the greatest usefulness can be made upon the same plan as is outlined above for a botanical museum. Every specimen in it would be selected to illustrate some fact or principle, and need not at all consist of an entire plant, but only the portion of it useful for this purpose. Drawings, photographs, full labelling, etc., may be incorporated in it much easier than in a museum. Indeed, I am inclined to question whether, in cases where means and room are very lim- ited, the herbarium on this plan may not be superior to the museum. It must, however, always suffer the draw- back of not being constantly visible to all, though even this might be overcome by keeping the sheets mounted in glass-fronted frames, like pictures. For use with a class the sheets would temporarily be placed in glass- fronted frames with removable backs. Of course the ordinary herbarium methods would apply to the prepa- BOTANICAL COLLECTIONS IO/ ration of specimens for such a collection.1 It may be that such an herbarium would find its highest usefulness as a private collection, built up to illustrate his own studies by the teacher, or by his best students. To illus- trate the possibilities of the plan, there are here added photographs of two sheets from my own collection, one ecological and one morphological (Fig. io).2 There is yet another important phase of herbarium- making in elementary teaching. Many teachers are accustomed to require from their students the making of one of a definite size as an integral and important part of their courses. There are many conditions under which this plan seems to me of value, as when facilities for any other actual work with plants are entirely want- ing, or when overworked or undertrained teachers can give the science but scanty attention ; and certainly it gives opportunity for careful manual work which always has moral value. But, viewed from the broader educa- tional standpoint, the requirement of an herbarium from elementary students seems to me quite uneconomical, in 1 The fullest account of herbarium methods is contained in W. W. Bailey's " Botanical Collectors' Handbook," and in Chapter X, Section IV, of Gray's "Structural Botany"; there is valuable matter also in the Her- barium Number of the Botanical Gazette (June, 1886); in Mr. Walter Deane's series of five articles " Notes from my Herbarium " in the Botanical Gazette, Vo\s. XX and XXI; and in L. II. Bailey's "Lessons with Plants," p. 437. On preserving colors in dried flowers, there is a valuable note in "Annals of Botany," Vol. I, p. 178. 2 These sheets but partly illustrate the value of the plan, as they were prepared as an experiment before it was fully worked out. io8 THE TEACHING BOTANIST 8 FIG. 10. — Photographs of two sheets from a small morphological and ecologi- cal herbarium ; X about i In the herbarium, the uses or the nature of the parts, with the names of the plants, are written where the numbers (ren- dered necessary by the method of engraving) stand in the cut, and are as follows : The left-hand sheet is devoted to Morphology, Stipules ; i, stipules as part of foliage (Geum sp., probably); 2, bud-coverings (Humulus lupulus) ; 3, spines (Euphorbia splendens) ; 4, part of foliage (Gallant) ; 5, all of foliage (Lathyrus Aphacd) ; 6, spines, also dwellings of protecting ants (Acacia sphcerocephala) ; 7, bud-coverings (Passiflora) ; 8, tendrils (Smilax) ; 9, bud-coverings (Liriodendron Tulipifera). The right-hand sheet is devoted to Ecology, Climbing Organs ; 10, axis of compound leaf (Bignonia); n, hooked epidermal spines (Rosa sinica) ; 12, aerial roots (Ficus repens) ; 13, axis of leaf (Lathyrus Aphaca) ; 14, axillary branch (Passiflord) ; 15, petioles (Clematis Virginiana); 16, main stem, twiner (Aristolochid) \ 17, extra-axillary branch (Ampelopsis Veitchii}\ 18, stipules (?) (Smilax}, BOTANICAL COLLECTIONS 1 09 that the labor necessary for collecting, drying, and mounting the specimens is largely not botanical, and is excessive in proportion to the amount learned through it about .plants. The question before us in such cases is not whether a thing is valuable or not, but rather, what will yield the largest returns for the time and energy expended. Moreover, the great majority of people have no taste for collecting, and extremely few ever keep it up ; so their school labors in this direction result in a bulky pile difficult to store and unattractive to preserve. It is not, I would repeat, that such herba- rium-making has in it no profit ; but simply that it is not as a whole profitable. On the other hand, under some circumstances, it may be very valuable, as when it is used to cultivate in those with a talent for natural history the collecting instinct, that first and plainest mark of the naturalist. The best plan, then, would seem to be to make the collecting voluntary, to be taken up by those whom it interests. As to the plan of such an herbarium, what has already been said about the museum herbarium ap- plies here with equal force, and I believe it may best represent, not the flora of a region, but principles of morphology and adaptation. I have found in my own experience that this plan interests many who care not at all for a floristic collection. The search in the native flora for examples of the different forms of stipules, for kinds of protective structures, illus- IIO THE TEACHING BOTANIST trations of marked adaptations to special habits, etc., must surely have a zest not inferior to the gathering of all the species of a given area, though this also is not to be disparaged. Moreover, a collection of this kind has a practicable limit of completeness, which a floristic one hardly has, and a small one expresses more than a floristic one of the same size. There are other plans on which herbaria may profitably be made. Professor L. H. Bailey, in his " Lessons with Plants ' (pp. 443-444), recommends special collections and suggests various sorts. In making these students' herbaria, most teachers require the standard size of mounting paper, the regu- lar genus covers, etc. But while this size (i6|-xii-| inches) is very convenient in large herbaria with proper cases, one or two hundred of such sheets make a package very awkward to store amongst a student's other effects, and not easy to consult on small crowded tables. This objection can be overcome if the sheets can be reduced to the size of a large book and kept stored among books. This I have found to be entirely practicable, and so advantageous that I have adopted it for a small private collec- tion of my own, even in the presence of the best facili- ties for storing the larger size. Sheets one-half the usual size will hold most specimens (see Fig. 10), and those too large can be treated precisely as are those too large for the ordinary size of sheets. The speci- BOTANICAL COLLECTIONS III mens are firmly glued to the half or somewhat smaller sheets, which are then placed between those covers used in colleges by students for holding any num- ber of sheets of paper, and held by paper fasteners. The thickness of the specimens is compensated by extra strips or stubs, and additions and rearrange- ments may be made with great ease. The collec- tion is then practically a book, and may be kept among books. The specimens are amply large for amateur's use. If it be thought that specimens so kept are particularly liable to dust and insect-rav- ages, it must be remembered that they are no more so than they are in the usual condition in which be- ginners keep them, and that if one cares, he may keep these books also in tight tin cases. It is some- times said in favor of the standard size that if a stu- dent continues his studies, his collection will form a nucleus for his larger herbarium ; but it is not fair to put the dozens who go no further to much incon- venience for the sake of the rare one who does. Specimens of the plants themselves include also the various anatomical preparations, skeletons to show the fibro-vascular system, wood-sections, etc., and particu- larly microscopical preparations. It is well to have a wide range of the latter for demonstration and for voluntary study by those whose tastes incline them to it ; and it is also profitable to have some sets for use in the regular class work, as recommended in certain 112 THE TEACHING BOTANIST places in the outlines in this book. These sets may be bought from various dealers in microscopical sup- plies, but are better made from time to time by the teacher himself, or by the specialists among his pupils. By the addition of a few each year a valuable col- lection will soon result. Proper cases, of many forms and prices, for storing them are supplied by dealers. Next in illustrative value after preparations of the plants themselves would come, theoretically, good models of them ; but practically I find good pictures or diagrams better, and shall treat these first. Of pictures, as a rule, photographs are best ; and where comprehensive or complicated things are to be shown, or where the actual living form and surroundings are important, they are indispensable. Their chief draw- back is that when large enough to be shown to a class they are very expensive. This can be overcome by photographing them on glass and projecting them to any desired size on a screen by the well-known stere- opticon method. This, however, is of little use in con- nection with laboratory work and is most useful where lectures are a part of the mode of instruction. Good photographs thus appealing vividly to the mind through the eye seem to me of the greatest value, especially for ecological studies (where, indeed, they are in- valuable), and for representing the natural appear- ance of many important plants from foreign parts which grow badly or not at all in greenhouses, or for BOTANICAL COLLECTIONS 113 showing the general topography of masses of vege- tation. A standard collection, selected by a specialist, of lantern slides of this character which could be purchased in one set, would be of great value and doubtless will soon be offered by some of the dealers, who already offer heterogeneous lots.1 The best stereopticon is one using the arc electric light; it is handier, cheaper, and better than the calcium and other forms, and is so powerful as to need no elaborate system of dark shades to the room, but may be used in almost full daylight. Many forms of such lanterns are offered ; I use to my satisfaction one made by J. C. Colt, of New York. The best screen is a smooth white wall. With such a lantern, and an ordinary microscope, one may also project microscopic objects upon a small screen, and thus show tissues, circulating proto- plasm in Nitella, etc. ; but in general the manipulation is so time-consuming and difficult that it is hardly worth while unless one has a liking for that very kind of thing. Where a lantern is impracticable, it is still decidedly worth while to collect photographs, of which many of value are now obtainable from return- ing tourists and other sources. A superb collection has recently been made available in Schimper's new 1 A great number indeed, selected by Koch, is published by Kriiss in Hamburg; a catalogue may be obtained from any dealer in botanical supplies. Unfortunately, these are mostly but woodcuts from books, not photographs from nature. Most American dealers in stereopticons also offer botanical slides. I 114 THE TEACHING BOTANIST work " Pflanzengeographie," on which further informa- tion is given in the next chapter. Large photographs of microscopic sections have some value, and an un- usually fine series, by Tower, is sold by Ginn and Company, Boston. After photographs, and for some purposes before them, come drawings or diagrams, which are of two general sorts, — those intended to show the very living appearance of plants or their parts, including enlarged views of small organisms, and those intended merely to help to a vivid vizualization of their structure. The former are not of much value unless very well done, true in perspective, and correct in coloring ; indeed, it may be said their value is in direct proportion to their artistic excellence. Good examples occur among the diagrams of Kny, Dodel, and Peter, to be mentioned below. Not much can be done toward making home- made diagrams of this kind unless an artist is available. In the second kind, however, those to simply help the mind to form a three-dimensioned conception of some complicated structure, the element of objective correct- ness is not so important ; and of such diagrams I think the very best is that which grows before the student's eyes on a blackboard under the hands of a teacher, with copious explanation and the aid of colored crayons, etc. Some skill in blackboard drawing is very desirable in the teacher, and I have no doubt that in time the in- creasing care devoted to the education of teachers of BOTANICAL COLLECTIONS 1 15 Botany will lead to their instruction in this useful art. Next to such diagrams, and for some purposes superior to them, are the excellent published diagrams of anat- omy in the Kny and in the Dodel series. The best of these is that of Kny, with full explanations in German, of which one hundred have appeared, each 84 x 68 cm., costing about $85 for the set, and the teacher should make every effort to obtain this series. They should be mounted on cloth for greater resistance to wear. Another valuable series is that of Frank and Tschirch, devoted to the physiological aspects of structure, sixty in number, of the same size as Kny's and also with explanations in German. The series of Laurent and Errera, fifteen in number, slightly larger than those of Kny, with explanations in German, French, and Eng- lish, is also good. If one cannot afford the Frank series, the latter is a fair substitute. The Dodel-Port series, slightly larger than the Kny series, is also valuable, as is the Peter series, published by Fischer in Berlin. Full particulars of these may be obtained through any of the dealers in botanical supplies or in foreign books. Many teachers value diagrams made by themselves or students above these printed kinds, holding that they have much more meaning, and hence value, and are also much cheaper. There are several methods of making them. One of the simplest and best is the use of strong, light-brown manila paper for the back- Il6 THE TEACHING BOTANIST ground, and India ink, applied with a brush, for the lines. This method is inexpensive, easy, and gives a pleasing combination. If one wishes to use colors, water-colors are best ; but a fair substitute may be found in colored crayons, which may be prevented from rubbing by a previous immersion in melted soft paraffin until the bubbles cease to come off, or by spraying the drawing through an atomizer with a weak solution of gum arabic.1 The best method known to me of hanging diagrams when in use has already been described (see Fig. 5). For storing they should be as nearly as possible of one size, of which the Kny series is a standard (84 x 68 cm.). They may then be very conveniently kept in shallow, upright cases built against the wall, a foot above the floor, with the front hinged on the bottom so as to drop forward a few inches at the top, as shown in the accom- panying diagrammatic cross-section ; a chain keeps the front from falling too far (Fig. 11). Another very valuable class of illustrations includes those in special monographs or technical papers ; and where a good library is available, free use should be made of these original sources of information. Many teachers would probably place models before diagrams in illustrative value, and chiefly because these, 1 Another method is fully described, and there are other valuable hints upon this subject, in "Natural History Charts and Illustrations," by J. W. Harshberger, in Education, April, 1897. BOTANICAL COLLECTIONS 117 \ \ \ \ like the objects they represent, are of three, not two, di- mensions. The latter point is, I think, of more theoreti- cal than practical importance ; and proper perspective in drawings, and especially in photographs, gives the same result. Moreover, models are far more difficult and expensive to construct with accuracy and truth to nature than are draw- ings, and this applies particu- larly to minutiae of structure. Botanical models are generally made of papier-mache or gela- tine, sometimes of wax or glass. Enlarged models of flowers or other parts, which are familiar to everybody in a living con- dition, seem such a grotesque parody of nature that they inspire more amusement than respect in the student, espe- cially in those kinds made to J FIG. it. — A successful box for come apart to show what is concealed within. To use such elaborate methods to illustrate facts which any one, with aid of a knife, can see in a minute with his own eyes seems to be carrying the good principle of clear illustration over the bounds of the useful into the ridiculous. It certainly is pos- \\ \\ \ \ \ \ V \ \ 1 x \ \ \ \ \ \ \ storage of diagrams, in cross- section. The dotted lines show it open. Scale, about i inch = i foot. Il8 THE TEACHING BOTANIST sible to refine illustration to a needless and enervating extent. These objections, however, do not apply to enlarged models of minute and difficult subjects, such as embryological development, nor to models of entirely unfamiliar objects ; and especially it does not apply to such models as the Blaschka series in the Botanical Museum of Harvard University, which inspire in the beholder no sensation except wonder and admiration. The principal makers of botanical models are Auzoux, of Paris, and Brendel, of Berlin, and in this country Kny and Company, of New York, make a specialty of their importation. There are purchasable, also, useful models of spiral vessels, of stomata made of rubber so they may be inflated, of fibro-vascular bundles in growth, etc., the usefulness of all of which varies with the individuality of the teacher. VII. ON BOTANICAL BOOKS AND THEIR USE BOOKS are the storehouses of knowledge, but in order to make full use of their advantages, one must learn where and how to seek in them that which he needs. How to use books profitably is therefore an important phase of the education of both teacher and student. For the teaching botanist, books fall into three classes : first, those to be read for self-improve- ment ; second, books of reference ; third, text-books for class use. In the preceding chapters I have tried to emphasize the real aim of scientific teaching, which is the culti- vation of the scientific habit of mind to the end that a scientific instinct may become a part of the student's mentality. No teacher who lacks this scientific habit of thought, or who has it but indifferently developed, can lead others into it, and he is likely to be the most successful teacher who has it the best developed. Self-improvement in this respect is therefore a first duty of every teacher, and while the best of all ways lies through original investigation, something can be accomplished by the reading of good books, especially such as are recognized as models of scientific exposi- 119 I2O THE TEACHING BOTANIST tion. In reading such books, ho\v~ver, it will be of little use to skim them for their facts or their rhetoric ; but the reader must minutely enter into the spirit of the work, try to put himself into the very mental attitude of the writer, with him view the original data, follow him as he marshals these into their proper relative positions, and try even to anticipate him in the deduction of his general principles. Happily there are many good books which will fully repay such reading. Upon the general subject of scientific education, and the true place of science in education, there are first of all the various addresses of Huxley, contained in his Collected Essays, particularly in the volume entitled " Science and Education." Of the greatest importance are also the addresses of President Eliot, now accessible in his " Educational Reform." Among books which are models of scientific argument, I think the first place should be given to Darwin's " Origin of Species " ; and if the teacher can thoroughly study but one book, it should be this. Its matter has some of it been superseded, but its spirit has not. Sug- gested naturally by this work are others of Darwin's, of which, perhaps, the " Power of Movement in Plants ' would most interest the botanist. Some of Huxley's biological essays are also not inferior to Darwin's in scientific exposition, and are much supe- rior in literary form, but their subjects are of less BOTANICAL BOOKS AND THEIR USE 12 1 botanical importance. There is, however, a series of botanical essays which are among the best of models, those of Dr. Asa Gray, contained in his " Scientific Writings," particularly those that relate to geographi- cal distribution, though nearly all in the two vol- umes will attract and instruct the American botanist. Another model of scientific writing, a work of charm- ing style and great force, and one that it will pay every teacher to read from cover to cover, is Sachs's " Lectures on the Physiology of Plants." Sachs's " History of Botany ' is also a classic, most readable and suggestive. There is one disadvantage common to all of these works, but one unavoidable in all scientific books while the science is advancing as rapidly as at present ; namely, much of their matter has been superseded by later researches. This draw- back the teacher can in part compensate by reading good new works as they appear, whose standing can be judged by the reviews of them in the botanical journals. It is, of course, of the greatest profit to the teacher to keep in touch with botanical progress through the botanical journals. The leading journal of this coun- try is the Botanical Gazette, which, in addition to technical articles, gives summaries of new discoveries, reviews of new books, and many notes of general interest, though naturally most of the matter is not utilizable except by those who have had thorough 122 THE TEACHING BOTANIST college courses in botany. The Bulletin of the Torrey Botanical Club, another leading journal, is very special in character. There is also much of botanical interest in Science, the leading American scientific journal, which every teacher of scientific sub- jects should certainly read regularly. Of a much more popular character is the Plant World ; and the Asa Gray Bulletin makes a special effort to provide material of value to school-teachers of ele- mentary classes in Botany. To teachers in New England who are studying the New England flora, Rhodora will be indispensable. Particulars as to price, etc., of these journals will be found in the Bibliography at the end of this chapter. Of course there are very numerous special botanical journals, but these mentioned are likely to be of most impor- tance to the American teacher of elementary courses. Sample copies may be obtained of any of them from the publishers. Where the teacher lives near a public library, the authorities can no doubt be induced to add some of these to their reading rooms, and indeed the rarer or more expensive botanical books are often obtainable in this way. There will be a place in the teacher's reading, and in that of his students also, for books of a less special character which may be read for both instruction and entertainment. Among such works, one of the very best is Wallace's " Malay Archipelago." Another classic BOTANICAL BOOKS AND THEIR USE 123 work is Bates's " Naturalist on the Amazons," and another is Belt's " Naturalist in Nicaragua," while for great interest as a book of travel combined with philo- sophical observations upon natural history, Forbes's " Wanderings of a Naturalist in the Eastern Archi- pelago ' ' must rank very high. To these I would add two books by Hudson, "The Naturalist in La Plata" and " Idle Days in Patagonia," which works in my opinion are quite unmatched for their combination of intense interest, clear scientific description, and fine literary form. Most of these books deal, it is true, much more with animals than with plants ; but they will not lack interest for the botanist on that account. If one would read a very entertaining and instructive book in German, he should take Haberlandt's " Eine botan- ische Tropenreise," a book of travels in the tropics by a botanist, a work commended to young botanists studying German. And all young botanists should study German, for they cannot go far in scientific study without a knowledge of it. A class of books very influential for good, and as yet far too few in number, are collections of essays upon important botanical topics, written authoritatively and attractively. Such works are useful both to teacher and students, and to general non-scientific readers as well, and they may attract to the science many who would not think of approaching it through its more scientific phases. Such a book, warmly to be commended for its 124 THE TEACHING BOTANIST combination of scientific spirit with attractiveness of style, is Geddes's " Chapters in Modern Botany." An- other is Sir John Lubbock's " Flowers, Fruits, and Leaves," devoted to some of the most attractive of ecological problems. Another is Sargent's recent " Corn Plants." Another, concerned mainly with physi- ological topics, is Arthur and MacDougal's " Properties of Living Plants." A very modest and little-known book of ecology is Dr. Gray's " How Plants Behave." Of this character, too, are the chapters in Kerner and Oliver's " Natural History of Plants," a superbly illus- trated four-volume work, which is a perfect treasury of ecological information and suggestion. It must be used with some caution, however, since its author is over- sanguine at times in his discovery of adaptations where others have not been able to see them. But caution is necessary in reading all books, and it is needful ever to remember that a thing is not necessarily true because even the best book says it is. Another volume of botanical essays full of interest and suggestiveness, dealing with evolutionary topics, is Bailey's " Survival of the Unlike," and indeed one may well bring the same author's " Lessons with Plants " into books of this class, especially for young people. Such books should be in every school library, and students allowed the freest access to them. The above list by no means includes all good books of this sort, but only some of the best of them, and all grades exist from these down to good BOTANICAL BOOKS AND THEIR USE 125 popular works, and through these to many that are of little or no value. I have not myself given attention to the popular books, but there are references to a few of the best in L. H. Bailey's "Lessons with Plants," P- 443- Passing next to the important subject of reference books, I shall enumerate the best in each department of work likely to be taken up in an elementary course. Reference books have several purposes for the teaching botanist : they are sources of information when new points come up on which information is needed ; they supply new methods in manipulation when new subjects are taken up ; they are full of suggestions to the brighter students who take pleasure in looking through them ; and they supply illustrations and additional subject- matter for fuller treatment of particular topics. They should always be accessible in the laboratory, and students should be encouraged to use them constantly, following up through the indexes the topics in which they may be interested. This habit of constantly con- sulting the literature is a most important one to cultivate in students. Where a school library cannot afford all of these books, but can buy some, the first mentioned under each of the classes here described should be selected. Text-books will be considered by themselves later. The following list is, of course, not intended to be exhaustive, but simply to include the most recent and authoritative works. The science is advancing so 126 THE TEACHING BOTANIST rapidly that even the best of books are soon superseded unless kept up with advances by new editions. Upon structural botany (i.e. external anatomy) the work of undisputed preeminence is Gray's " Structural Botany," a very clearly written and well-illustrated work ; and in condensed form the same merits prevail in his " Elements of Botany." The morphology of these works, however, is not modern in spirit, but of a formal sort, largely laid aside by modern investigation. On morphology the most authoritative work is Goebel's " Organographie der Pflanzen," now appearing in parts, a work for which there is no equivalent in English, and which, it is to be hoped, will soon be translated. There is really at present no work in English giving the results of modern studies on the morphology of the higher plants, though several of the text-books men- tioned later contain it in part. In physiology we may distinguish two classes of works, those giving practical directions for experimen- tation and the general hand-books or text-books. Of the former, MacDougal's " Experimental Plant Physi- ology " is one of the simplest and most practical works. Darwin and Acton's " Practical Physiology of Plants ' (second edition) is most excellent and suggestive, while Detmer's widely used work, translated into English by Moor as " Practical Plant Physiology," combines a practical laboratory guide with a good text-book of the subject. Of general works on plant physiology, the BOTANICAL BOOKS AND THEIR USE 127 most readable and illuminating, though one now much behind the present state of knowledge, is Sachs's " Lec- tures on the Physiology of Plants," a work that should be much used for the value of its point of view. The greatest work on physiology is Pfeffer's "Pflanzen physi- ologic," of which Volume I has appeared, with Volume II to follow soon; the work is being translated into English, and will be indispensable to every botanical library. Another most excellent book, very direct and suggestive, is Sorauer's work, translated by Weiss as " Popular Treatise on the Physiology of Plants." Vines's " Lectures on the Physiology of Plants ' is also very excellent, though now needing revision. A book much used in this country is Goodale's "Vegetable Physiol- ogy," a clear synopsis of its subject, but now also much in need of revision. Of course the various modern text-books to be mentioned later contain physiological sections. The very important and rapidly developing subject of ecology has not yet many good works in English. First among them are several of Darwin's books, which are foundation works in some phases of ecology. Highest among general works would stand Kerner and Oliver's " Natural History of Plants," which is to be consulted with the caution already referred to. In German there are important works by Ludwig and by Wiesner. In one of its most practical and interesting aspects, namely, in the explanation of the causes of 128 THE TEACHING BOTANIST the topography or physiognomy of vegetation, and the distribution of the different forms, there is a most admirable work by Warming, written in Danish, and translated into German under the name " Oekologische Pflanzengeographie," and now being translated into English. More recent, and noteworthy for its great authority, its remarkably full and clear treatment of its subject, and its superb illustrations, is Schimper's " Pflanzengeographie auf physiologischer Grundlage." This work should be in every botanical library for its illustrations alone, even if one cannot read German. It supplies by far the best collection of botanical, espe- cially ecological, photographs ever published. One of the most important phases of ecology is that of the . locomotion of pollen (often wrongly called cross-ferti- lization); and on this there is a most valuable work by M tiller, translated into English by Thompson, under the title " Fertilisation of Flowers." This is in great part arranged on the dictionary principle, so that it is easy to find out what is known of the pollination of any particular flower. Much has been discovered since its publication ; and a recent work by Knuth, "Handbuch der Bliitenbiologie," in two volumes with more to come, brings the subject down to this date, at least for Euro- pean plants. On the attractive subject of seed-loco- motion there is no single large work in English, but an excellent little book is Beal's " Seed Dispersal." Darwin's works on fertilization of flowers, and his BOTANICAL BOOKS AND THEIR USE 129 "Climbing Plants," contain much ecology, and two of the most recent text-books, those by Barnes and by Atkinson, contain sections specially devoted to it. For microscopic anatomy there is one very excellent work, full of the most practical and the most scientific information, Strasburger's " Das botanische Practicum," of which there is a condensation called " Das kleine botanische Practicum," translated by Hillhouse, under the title " Practical Botany." By aid of this book one could, without a teacher, work through a valuable course in plant anatomy ; and it would be a great advantage if there were similar works for other phases of the science. On the ecological phases of the minute anatomy of plants the great work is Haber- landt's " Physiologische Pflanzenanatomie," a work that is unfortunately not translated. De Bary's work, trans- lated by Bower and Scott as " Comparative Anatomy of the Vegetative Organs of Phanerogams and Ferns," is a standard, of great fulness and authority. On the natural history of the groups of plants are sev- eral excellent works, of which the greatest is Engler and Prantl's "Die natiirlichen Pflanzenfamilien," in German, of which twelve volumes have appeared with three or four to follow, profusely illustrated and most authorita- tive. Goebel's work, translated as " Outlines of Special Morphology and Classification," is very valuable, but needs revision. More recent is Warming's excellent work, translated by Potter, under the title " Systematic K I3O THE TEACHING BOTANIST Botany." Some of the text-books to be mentioned below, notably Strasburger's and Vines's, give good sy- nopses of the groups, as do also Atkinson's and Barnes's works. For an account of the groups from the ecologi- cal and evolutionary standpoint, there is an admirable little work, entitled " Evolution of Plants," by Camp- bell, which every school library should possess, and which should be well read in connection with any school course treating the natural history of plants. A group of books which from some points of view may be considered as text-books, but which I think rather should be viewed as books of reference, are the laboratory guides. These are books giving full labora- tory directions for the practical working out of impor- tant topics, and the student is supposed to have them open before him as he works. The great objection to them as a class is that they necessarily presuppose certain materials, and these it is by no means easy to provide ; and the restriction they impose upon a good teacher is unbearable. On the other hand, as sugges- tions for the construction of guides by the teacher for his own class, they have much value, and it is chiefly for this purpose the guides in Part II of this book are offered. Of the laboratory guides, one of the most recent and excellent is Spalding's " Intro- duction to Botany," which, however, gives no attention to practical physiology, though it has excellent summary chapters containing much ecology. Another is Setch- BOTANICAL BOOKS AND THEIR USE 131 ell's " Laboratory Practice for Beginners in Botany," which is confined to the higher plants and excludes practical physiology, though it gives great attention to ecology. It is prepared upon the unusual plan of telling the student in detail what he will see — a plan that few teachers consider pedagogically profitable. MacBride's " Lessons in Botany" is excellent within its limits, but it is too exclusively structural. Older books of this class, but excellent and influential nevertheless, are the botanical part of Huxley and Martin's " Ele- mentary Biology ' and Arthur, Barnes, and Coulter's " Manual of Plant Dissection." The latter work, in particular, has been much and profitably used in this country. Many practical laboratory directions are given in several of the text-books to be mentioned below, notably Bergen's, Barnes's, and Atkinson's. Intermediate between these laboratory guides and true text-books come books that are primarily guides to observation, though they may also give much infor- mation, and to some extent are usable as text-books. A very notable and excellent work of this sort is L. H. Bailey's " Lessons with Plants," a book replete with suggestions, new points of view, and valuable infor- mation. Another in the same spirit, but less elaborate, is Miss Newell's "Outlines of Lessons in Botany" with its accompanying valuable Readers. We pass next to consider text-books proper- -works intended to be studied fully and carefully by the mdi- 132 THE TEACHING BOTANIST vidual student. Such books were formerly all-impor- tant and all-sufficient in botanical education. With the rise of the laboratory method of instruction they fell into disfavor, and many teachers attempted to teach without them or with the aid only of laboratory guides, on the ground that the student should learn only from nature. Experience, however, is showing that labora- tory study, while absolutely essential for the training of natural powers and the correct understanding of natural facts and phenomena, is, nevertheless, not alone suffi- cient ; for, dealing as it necessarily does, even at its best, with a few selected types, the view it gives of the sub- ject is more or less disconnected and incomplete, the more especially since many topics of the greatest im- portance cannot for practical reasons be introduced into the laboratory at all. Of course, instruction by lectures, or talks by the teacher, partly overcomes these draw- backs; but I, in common with other teachers, have found after trial of different plans that it is an immense advantage to the students to have some good book to which they can turn for additional information, and for correcting the many errors and distortions that inev- itably arise from lectures and laboratory work alone. It is well to require students to read such a book with great care. It does not matter whether or not the book follows the same course as the teacher's instruction, though the more nearly they correspond the better. This book should be a text-book in the true sense, a BOTANICAL BOOKS AND THEIR USE 133 book of botanical texts, as clearly, attractively, induc- tively, synthetically written as possible. It should not be complicated by laboratory directions or pedagogic matter, all of which belong in a separate work. Indeed, the later text-books show a tendency to separate the text-book proper from the laboratory guides and directions, and to make the former simply an attractive and instructive reading book. Such a separation has always been shown in the German text-books, and is carried out in this country in Barnes's recent " Plant Life," and the logical extreme of this principle has produced the present work. In the use of the text- book there is one golden rule, i.e. never to require reading in it upon any laboratory topic until after that topic has been studied in the laboratory. The labora- tory study not only allows of much more intelligent and appreciative reading upon the topics there taken up, but each topic thus studied forms a point of van- tage from which excursions into the unknown may profitably be made. We all know how much more any account of a country or city means to us after we have been there, even though we have seen but a small part of it ; and it is so with accounts of organisms. Of good text-books for use in elementary courses there are several. The latest published in this coun- try is Atkinson's " Elementary Botany," a concisely written, modern, finely illustrated work, from the physiological standpoint, with much attention to mor- 134 THE TEACHING BOTANIST phology and ecology, and constant practical direc- tions for laboratory study. Similar in these respects is Barnes's " Plant Life," a book but a few months older ; but this is less a laboratory book, and more a work for reading. More recent than either is Vines's " Elementary Text-book of Botany," a thorough and valuable work, whose plan, however, hardly fits our methods of instruction in this country as closely as do those of Barnes and of Atkinson. Somewhat the same may be said of a text-book which is perhaps in the abstract the best that has appeared in recent years, the " Text-book of Botany," by Strasburger, Noll, Schenck, and Schimper. This book is written by four leading scientific experts, and is one of the most reliable, readable, and best illustrated of botani- cal books, and, whether used as a text-book or not, it is an invaluable reference work that no library should be without. It may be bought in two parts, of which the first is of most importance to the aver- age teacher. Another recent American text-book is that by Curtis, " An Elementary Text-book of Bot- any." Another work, particularly adapted to schools, is Bergen's " Introduction to Botany," which com- bines both text-book and laboratory directions, and is modern in matter and spirit. For schools that have scanty equipment and cannot give abundant time to a course, this work is particularly advantageous. Gray's " Elements of Botany ' is in its own field a BOTANICAL BOOKS AND THEIR USE 135 most excellent work and one that can hardly be superseded ; but its standpoint is not modern, and its morphology is in places out of harmony with pres- ent opinions. Another excellent work that has had wide use is Bessey's " Botany," of which there is an abridged edition called " The Essentials of Botany." Clark's " Laboratory Manual of Botany ' is a work prepared in the modern spirit, but it has not been favorably received by those competent to judge of its merits from a scientific point of view. The various laboratory guides by Spalding, Setchell, and others have already been referred to. There are, of course, yet other text-books, including several written in Eng- land, in Germany, and in France. So far as text-books for elementary work are concerned, it is more likely that one written in any particular country will be better adapted to methods of instruction in vogue there than would be the case with one written in another country. And it must also be remembered that, owing to the advancement of science, those books written by ac- tive scientific experts, and those that are newest, are likely to be the best. There remains yet one other class of books to be considered, -—manuals for use in classification. The classic work for northeastern North America is Gray's " Manual," sixth edition. The system of classification represented by it, however, is being gen- erally abandoned, and a new edition is needed. A 136 THE TEACHING BOTANIST special edition with leather cover and thin paper is issued for use in the field. Covering about the same ground and embodying the newer classification, though also embodying a system of naming of the plants not yet widely accepted, is Britton and Brown's " Illustrated Flora," in three volumes. This gives a simple outline illustration for each species. A kind of work that is very much needed, and which is sure in the future to be prepared, is one that will be at the same time a synopsis of classification and of nat- ural history, giving the habits and marked adapta- tions of each species. For the Southern States there is Chapman's " Flora," and for the Rocky Mountain region, Coulter's " Manual." For the Pacific slope there is not yet a compact manual comparable with the above-mentioned, though Greene's " Manual of the Botany of the Region of San Francisco Bay," and Howell's " Flora of Northwest America," partly cover that region. Of reference works for such stud- ies, there are many, of which Gray's " Synoptical Flora of North America ' is the most important. For the study of garden plants, Gray's " Field, Forest, and Garden Botany," revised by Bailey, is the only work. In this connection may be mentioned mono- graphs of special groups, of which by far the great- est, and one of the most splendid works in every respect that have ever appeared, is Sargent's " Silva of North America," in twelve volumes, exhaustively BOTANICAL BOOKS AND THEIR USE 137 describing every species of tree in North America. Of a similar character is Eaton's " Ferns of North America," which describes, though on a less elabo- rate scale, all of our ferns. Of books designed as guides to the study of particular groups, there are a few of real authority. Underwood's " Our Native Ferns and their Allies" is one of these, and of course there are many popular works of this character, whose consideration hardly belongs in the present work. If the teacher is interested in other groups, or wishes other information about botanical books, he should consult the Professor of Botany in the nearest large university. BIBLIOGRAPHY List of works referred to in Chapter VII and elsewhere in this book. The prices are from publishers1 lists, and are usually sub- ject to discount. They are for bound copies. Care should be taken to secure always the latest editions. Arthur, J. C., Barnes, C. R., and Coulter, J. C. Handbook of Plant Dissection. New York. Henry Holt & Co. 1887. $1.20. Arthur, J. C., and MacDougal, D. T. Living Plants and their Properties. New York. Baker & Taylor. 1898. $1.25. Asa Gray Bulletin. Bi-monthly. Washington, D.C. 50 cents a year. Atkinson, G. F. (1) Elementary Botany. New York. Henry Holt & Co. 1898. $1.25. (2) The Study of the Biology of Ferns by the Collodion Method. New York. The Macmillan Co. 1894. $2.00. 138 THE TEACHING BOTANIST Bailey, L. H. (1) The Survival of the Unlike. New York. The Macmillan Co. 1897. $2.00. (2) Lessons with Plants. New York. The Macmillan Co. 1898. $1.10. (3) Garden Making. New York. The Macmillan Co. 1898. $1.00. Bailey, W. W. Botanical Collector's Hand-book. Salem, Mass. George A. Bates. 1881. $1.50. A new edition is promised. Barnes, C. R. Plant Life, considered with Special Reference to Form and Function. NewYork. Henry Holt & Co. 1898. $1.12. Bates, H. M. The Naturalist on the Amazons. London. John Murray. 1892. iSs. Beal, W. J. Seed Dispersal. Boston. Ginn&Co. 1899. 40 cents. Belt, T. The Naturalist in Nicaragua. London. E. Bumpus. js. 6d. Bergen, J. Y. Elements of Botany. Boston. Ginn & Co. 1896 and later. $1.20. Bessey, C. E. (1) Botany for High Schools and Colleges. New York. Henry Holt & Co. 1885 and later editions. $2.20. (2) The Essentials of Botany. New York. Henry Holt & Co. 1896. $1.08. Botanical Gazette. Monthly. Chicago. The University of Chicago. $4.00 a year. Britton, N. L., and Brown, A. An Illustrated Flora of the Northern United States, Canada, etc. New York. Charles Scribner's Sons. 3 vols. 1896-1898. $3.00 a volume. Bulletin of the Torrey Botanical Club. Monthly, Lancaster, Pa. $2.00 a year. Campbell, D. H. (1) The Structure and Development of the Mosses and Ferns. New York. The Macmillan Co. 1895. $4.50. (2) Lectures on the Evolution of Plants. New York. The Macmillan Co. 1899. $1.25. Chapman, A. W. Flora of the Southern United States, etc. American Book Co. 1897. $3.60. Clark, C. H. A Laboratory Manual of Practical Botany. New York. American Book Co. 1898. 96 cents. BOTANICAL BOOKS AND THEIR USE 139 Coulter, J. M. Manual of the Botany of the Rocky Mountain Region. New York. American Book Co. 1885. $1.62. Curtis. C. C. Text-book of General Botany. New York. Long- mans, Green, & Co. 1897. $3.00. Darwin, Charles. (1) The Origin of Species. 1885. Sixth edition. $2.00. (2) The Power of Movement in Plants. $2.00. (3) Insectivorous Plants. $2.00. (4) Movements and Habits of Climbing Plants. $1.25. (5) The Various Contrivances by which Orchids are fertilized by Insects. $1.75. (6) The Effects of Cross and Self Fertilization in the Vegetable Kingdom. $2.00. (7) Different Forms of Flowers on Plants of the same Species. $1.50. All published by D. Appleton £ Co. New York. Darwin, F., and Acton, E. H. Practical Physiology of Plants. Cambridge. Second edition. 1897. 4.3. 6d. De Bary, A. Translated by Bower and Scott. Comparative Anatomy of the Vegetative Organs of Phanerogams and Ferns. Oxford. The Clarendon Press. 1884. $5.50. Detmer, W. Translated by Moor. Practical Plant Physiology. New York. The Macmillan Co. 1898. $3.00. Eaton, D. C. The Ferns of North America. Boston. Bradlee Whidden. 1893. 2 vols. $20.00 per volume. Eliot, C. W. Educational Reform. New York. The Century Co. 1898. $2.00. Engler & Prantl. Die natuerlichen Pflanzenfamilien. Leipzig. W. Engelmann. Now appearing in parts. 12 volumes are complete. Forbes, H. O. Wanderings of a Naturalist in the Eastern Archi- pelago. London. Sampson, Low & Co. 1885. 2is. Geddes, P. Chapters in Modern Botany. New York. Charles Scribner's Sons. 1893. $1.25. Goebel, K. (1) Translated by Garnsey and Balfour. Outlines of Classi- fication and Special Morphology of Plants. Oxford. Clarendon Press. 1887. $5.25. (2) Organographie der Pflanzen. Jena. Gustav Fischer. Now appearing in parts. 140 THE TEACHING BOTANIST Goodale, G. L. Physiological Botany. Vol. II of Gray's Botan- ical Text-book. New York. American Book Co. 1885. $2.00. Gray, Asa. (1) Scientific Writings. Edited by C. S. Sargent. Boston. Houghton, MifHin & Co. 2 volumes. 1889. $6.00. (2) Structural Botany. Part I of Gray's Botanical Text-book. New York. American Book Co. 1880. $2.00. (3) Manual of the Botany of the Northern United States. Sixth edition. New York. American Book Co. 1890. $1.62. Field edition, $2.00. (4) Elements of Botany. New York. American Book Co. 1887 and later editions. 94 cents. (5) Field, Forest, and Garden Botany. Revised by L. H. Bailey. New York. American Book Co. 1895. $1.44. (6) How Plants Behave. New York. American Book Co. 1875. 54 cents. Greene, E. L. Manual of the Botany of the Region of San Francisco Bay. San Francisco. Curry & Co. 1894. $2.00. Haberlandt, G. (1) Eine botanische Tropenreise. Leipzig. W. Engelmann. 1893. 9.25 marks. (2) Physiologische Pflanzenanatomie. Leipzig. W. Engel- mann. 1896. 1 8 marks. Howell, T. Flora of Northwest America. Portland, Ore. Pub- lished by the author. Now appearing in parts. Hudson, W. H. (1) The Naturalist in La Plata. London. Chapman & Hall. 1892. i6s. (2) Idle Days in Patagonia. London. Chapman & Hall. 1893. 143. Huxley, T. H. Science and Education. Vol. Ill of his Collected Works. New York. D. Appleton & Co. 1894. $1.25. Huxley, T. H., and Martin, H. N. A Course of Elementary Instruc- tion in Practical Biology. London. The Macmillan Co. 1886. i os. 6d. Kerner von Marilaun, A. Translated by Oliver. The Natural History of Plants. New York. Henry Holt & Co. 4 volumes. 1894-1896. $15.00. BOTANICAL BOOKS AND THEIR USE 141 Knuth, K. Handbuch der Bliitenbiologie. Leipzig. W. Engel- mann. 1898. 2 volumes. 28 marks. Lubbock, Sir J. Flowers, Fruits, and Leaves. London. The Macmillan Co. 1884. 43. 6d. Ludwig, F. Lehrbuch der Biologic der Pflanzen. Stuttgart. F. Enke. 1895. 14 marks, unbound. MacDougal, D. T. Experimental Plant Physiology. New York. Henry Holt & Co. 1895. $1.00. MUller, H. Translated by Thompson. The Fertilisation of Flowers. London. The Macmillan Co. 1893. 2is. Newell, Jane H. Outlines of Lessons in Botany. Parts I and II, with Readers, Parts I and II. Boston. Ginn & Co. 1892. Outlines. 90 cents each ; Readers, 70 cents each. PfefFer, W. Pflanzenphysiologie. I. Stoffwechsel. Leipzig. W. Engelmann. 1897. 23 marks. An English translation is being prepared. Plant World, The. Monthly. Binghampton, N.Y. $1.00 a year. Rhodora. Monthly. New England Botanical Club. Boston. $1.00 a year. Sachs, J. (1) Translated by Garnsey and Balfour. History of Botany. New York. The Macmillan Co. 1890. $2.50. (2) Lectures on the Physiology of Plants. Translated by Ward. Oxford. Clarendon Press. 1887. (Now out of print.) Sargent, C. S. The Silva of North America. 12 volumes. Boston. Houghton, Mifflin & Co. 1892-1899.- $25.00 a volume. Sargent, F. L. Corn Plants. Boston. Houghton, Mifflin & Co. 1899. 75 cents. Schimper, A. F. W. Pflanzengeographie auf physiologischer Grundlage. Jena. Gustav Fischer. 1899. 27 marks, unbound. Science. Weekly. New York. The Macmillan Co. $5.00 a year. Setchell, W. A. Laboratory Practice for Beginners in Botany. New York. The Macmillan Co. 1897. 90 cents. Sorauer, P. Translated by Weiss. A Popular Treatise on the Physiology of Plants. London. Longmans, Green, & Co. 1895. 9-y. Spalding, V. M. Guide to the Study of Common Plants. Boston. D. C. Heath & Co. 1895. 90 cents. 142 THE TEACHING BOTANIST Strasburger, E. (1) Das botanische Practicum. Jena. Gustav Fischer. 1897. 22.50 marks. (2) Das kleine botanische Praktikum. Third edition. Jena. Gustav Fischer. 1897. 7 marks. The second edition of the latter is translated by Hill- house as Practical Botany. New York. The Macmillan Co. 1897. $2.50. New edition promised. Strasburger, E., Noll, F., Schenck, H., Schimper, A. F. W. Trans- lated by Porter. A Text-book of Botany. New York. The Macmillan Co. 1898. $4.50. In four sections, and Sections I and II may be had together without III and IV. $2.50. Underwood, L. M. Our Native Ferns and their Allies. New York. Henry Holt & Co. 1888. $1.25. New edition promised. Vines, S. H. (1) An Elementary Text-book of Botany. New York. The Macmillan Co. 1898. $2.25. (2) Lectures on the Physiology of Plants. Cambridge. Uni- versity Press. 1886. 21 s. Wallace, A. R. Malay Archipelago. London. The Macmillan Co. 1891. 6s. Warming, E. 1 i ) Translated by Potter. A Hand-book of Systematic Botany. New York. The Macmillan Co. 1895. $3.75. (2) Translated into German by Knoblauch. Lehrbuch der OekologischeaPflanzengeographie. Berlin. Geb. Born- traeger. 1896. 8 marks. Wiesner, J. Biologie der Pflanzen. Vienna. 1889. A new edi- tion is in preparation. VIII. ON SOME COMMON ERRORS PREJU- DICIAL TO GOOD BOTANICAL TEACHING ONE of the chief obstacles to the advancement of knowledge is the difficulty of securing the introduction of the results of new researches into general circula- tion. Errors once in possession of the field, especially if backed by the authority of some great name, persist long after they are disproven, particularly when easier to understand, or pleasanter to believe than the newer truths. I shall here point out some of the more preva- lent errors in Botany, not including cases still in doubt, but only those on which competent authorities agree. Very widely spread is one popular error about Bot- any ; namely, that it is synonymous with the study of flowers, and hence of no great value except as an accomplishment of fashionable boarding-schools or an appropriate hobby for elderly persons of leisure. This belief is a natural one, for until lately it has consisted in this country largely in the study of flowers, and still does to far too great an extent. We cannot expect the error to be corrected until botanical courses gener- ally represent the real condition of the science. Another error, prevalent even among college teachers, is, that Botany cannot be taught as a science in the 144 THE TEACHING BOTANIST high schools because high school students are not mature enough, and cannot think. It is true that many of them do not think, but this is because their think- ing powers are aborted by disuse or crushed to earth by the weight of incessant memory work. But experience shows that, given a fair chance, high school students can think, and are fully able to profit by even the most scientific treatment of the subject. These, however, are but minor errors, though it is well for the teacher to be on the watch for them, and to attack them whenever they appear. More serious are the errors of botanical fact and theory current among teachers themselves. Thus, morphology, as commonly taught in our schools, is dominated by a rigid formal- ism, an inheritance from the idealistic system of Goethe, which implies modification within the limits of some distinct plan rather than modification in adaptation to conditions as they exist. It is commonly taught that the higher plant consists of root, stem, and leaf (with, perhaps, also " plant hair "), and that every part of it is composed of some one or more of these, which, like the chemical elements, may be variously combined and united, but retain their identity through it all. This view is a natural one where evidence is drawn from comparative anatomy alone, and most of those who have held it have been students in that line and not in embryology. It is a very poor working hypothesis, for it leads always to a blank wall blocking further prog- SOME COMMON BOTANICAL ERRORS 145 ress, and to inconsistencies requiring the most artful dodging. The central point in this doctrine is the belief in the comparative immutability of the nature of the plant members or elements. All modern research, however, is denying this belief and replacing it by the opposite principle, viz. that difference of degree of de- velopment passes over into difference of kind of struc- ture, thus leading to the formation of new elements or members which become centres of variation, modifi- cation, adaptation upon their own account, and more or less independently of their original nature. Thus the ovary is composed of carpels, which originally were spore-bearing leaves. Now, when an ovary must vary adaptively to some new influence, it does not need to go back to consult the rules governing its behavior when it was a set of sporophylls, but it responds as a unit, as an ovary ; it has itself become a member or element. It is always necessary in morphology to keep plain the difference between historical origin and present nature. Historically, an American is an Englishman, but he does not on that account now act or think as an Eng- lishman ; he has a new character, he is an American. So, historically, the ovary is a set of leaves ; but it does not act like a set of leaves, but like what it now is, an ovary. The placenta is another good example of this. Generally it is said to represent the united edges of infolded carpellary leaves, but one has to perform complicated mental gymnastics to interpret all placentae 146 THE TEACHING BOTANIST in this way. The real explanation doubtless is, that, although the placenta did thus originate, it has attained to independent dignity as a morphological element, and proceeds to act as a unit, varying and adapting itself to its conditions, largely independently of its original nature. Of course there are all degrees of this inde- pendence of original nature ; and while some structures have broken away entirely from it, others are more or less bound by it ; but the recognition of the principle, really the fundamental principle of modern morphol- ogy, is very important. Formalism in morphology, based upon comparative anatomy, must be modified by realism based upon embryology. Unfortunately there is as yet no authoritative work in English treating fully this subject. Perhaps the greatest of all current morphological errors is that which attempts to homologize ovules and pollen with something on the green shoot. It is often taught that the ovule represents an altered piece of the edge, perhaps a tooth, of the leaf, while the pollen is the parenchyma with epidermis rounded out to form the anther. It is, however, now known beyond any doubt that the ovule (strictly, its nucellus) is a spore-case, a lineal descendant of the spore-cases of liverworts, and hence is much older than the differentiation of the parts of the leafy shoot ; and the same is true of the pollen and anther, which represent also ancient spores and spore- cases. Hence the pollen and ovules are not modified SOME COMMON BOTANICAL ERRORS 147 parts of a vegetative shoot, but independent structures of long ancestry and independent dignity. Another common error is that of attempting to ho- mologize the parts of the stamen and of the carpel with the parts of the green leaf. Thus, it is often said that the filament represents the petiole, and the anther the blade ; while in the carpels the ovary wall is said to be the blade, the style the elongated tip, and the stigma the extreme end turned back ; and much mental ingenuity is needed to show how some of the more specialized styles and stigmas fit into this scheme. In fact, while the precise origin of the stamens and carpels is not beyond doubt, this much is certain, that they are the descendants of the sporophylls of cryptogamic plants, and there is a very strong probability that these sporophylls never have been green foliage leaves ; and even if they were, it \vas at a time before the differ- entiation of the modern specialized foliage leaf with its blade, petiole, and stipules. It is, therefore, correct to regard carpels and stamens as morphologically leaves ; but they must be viewed as having followed a course independent of that of foliage leaves, each developing the parts necessary to its function without any regard to the developments of the other. Hence it is not possible to homologize the parts of one with the parts of the other. Another very common error, perpetuated by its use in all systematic works, is, that inferior ovaries represent 148 THE TEACHING BOTANIST united carpels and calyx. Nothing could be more thor- oughly disproved, or is more easy to disprove by embryo- logical study than this. Embryology shows that, in the great majority of cases at least, the inferior ovary is simply a receptacle which has grown up into a cup, carry- ing all the other parts upon its top, the carpels coming finally to form simply a roof over the cavity of the ovary (as shown in Fig. 28). This fact at once dis- poses of many of the inconsistencies inseparable from the " calyx-adnate ' theory. Again, where a calyx- or corolla- or perianth-tube is formed, it is usual to consider that this tube consists of united sepals, petals, etc., but it is probable that only the free parts or teeth of the corolla or calyx represent the original distinct petals or sepals, while the tube is a band of leaf tissue that grows up as a ring leaf, bearing the separate leaves on its top ; it is thus a new structure and not the united bases of the old perianth parts. There are also some minor errors current, of which the following are most important : First, it is usually supposed that root, stem, and leaf of the higher plant are members of equivalent worth. In fact, this is not the case, for root is in every way much more distinct from stem and leaf than these are from one another. The best division then is into root and shoot, with the latter differentiating into leaf and stem. Another error is, that the higher plant is made up of certain elemental parts called phytomera, each of which is composed of a SOME COMMON BOTANICAL ERRORS 149 joint of stem and one or more leaves. The support for this idea is found partly in the jointed appearance of many plants like grasses, and partly in the fact that the so-called phytomer is usually the smallest part of a plant that will grow. The latter, however, is a purely physiological phenomenon of no morphological signifi- cance ; a piece of stem can usually put out roots, and some leaf surface is necessary to make food to enable the plant to continue to grow. The jointed appearance is purely incidental; the nodes are the places where the fibrovascular bundles branch to run out into the leaves and to unite with one another, and hence the node and its accompanying internode have simply an anatomical and not a morphological meaning. Embryology shows that the plant, so far from being made by a series of phytomera growing one out of another, is made by continuously growing vegetative points, throwing off laterally certain superficial portions which become leaves, in whose axils the points branch. The true morphological relationships of the parts of the higher plants are expressed in the following table :- Root Shoot ^ Stem „ Blade [Leaf ( Foliage •' Petiole Stipules Floral Petals and Sepals Sporophylls { Macrosporophylls (Carpels) . I Microsporophylls (Stamens). Sporangia (containing J Macrosporangia (Ovules) . . Spores) L Microsporangia (Anthers) . . ) The 150 THE TEACHING BOTANIST Among errors very dear to us is the belief that monstrosities are reversions to an earlier condition, and hence good guides to the past history of organs or species. It is true they may be, and of course often are ; but they so frequently are not that great caution must be exercised in using them as guides to phylogeny. If the turning of a petal green is taken to prove that the petal was once a foliage leaf, then the turning red or yellow of the leaf under the flower of a tulip must be taken to prove that this leaf was once a petal, which is, of course, not to be believed ; hence the turning green of petals means nothing more than a disturbance of nutri- tion conditions. This principle applies to the cases where carpels become leaves and the ovules leaf-like bodies, which need not mean that these were once of a green leaf nature, but only that the plant has for some reason unknown made its materials build green leaf tissue instead of carpellary tissue at that place. Very common and serious are physiological errors, of which perhaps the most widespread is the belief that animals and plants are the exact opposites of each another with reference to the taking in and giving off of the two very important gases, carbon dioxide and oxygen. In a general way this is true, but not in the sense in which it is usually meant. In fact, in all of their processes of growth, movements, etc., animals and plants behave precisely alike with reference to these two gases, in both cases taking in oxygen and giving out SOME COMMON BOTANICAL ERRORS 151 carbon dioxide. But it happens that green plants have an additional power, utterly lacking in animals, to form their food from certain gases, minerals, and water, and in this process (photosynthesis, or assimilation) carbon dioxide is absorbed and oxygen is given off. In green plants, in bright light, this process is so very much more active than the process of respiration, that the plant as a whole does give off much more oxygen than carbon dioxide, but in darkness the food-making stops, and the plant then gives off carbon dioxide precisely as animals do. It is therefore only in virtue of their possession of this single extra power that plants reverse the process of animals ; in nearly all others of their important vital actions they behave like them. Much misunderstood is the nature of plant food. It is generally taught that plant food consists of carbon dioxide, minerals, and water. If by food one means anything taken into the organism, this is correct ; but if by that term one means the substance out of which the organism builds up new tissues, repairs waste, and obtains energy for its own vital work, then this is in- correct. In reality the plant has the power, lacking in animals, of absorbing the carbon dioxicfe, water, and minerals, and of making from these starch or a related substance ; and this starch is then used as food in essentially the same manner as animals use it. It may be said, then, that plants form their food from the raw materials, which properly are not food at all. Of 152 THE TEACHING BOTANIST course animals are entirely dependent for their food upon that made by plants. Another error is the assumption that the carrying of pollen from flower to flower by insects is a part of the process of reproduction, and this is intensified by the common expression of " cross-fertilization ' used to describe the process. But really this process has nothing directly to do with the act of fertilization, but it is simply one of the methods the plant has adopted to overcome the difficulties imposed by the sessile habit ; that is, it is the mode of locomotion of the male to the female element, and is much better described as pollen- locomotion or cross-pollination. When one studies the phenomena of irritability, he usually passes through a stage in which he believes that plants possess a certain intelligence. The more careful study of the phenomena, however, leads to the conclu- sion that it is not intelligence they possess, though they have a power producing some apparently similar results. Irritability is more nearly comparable with reflex action, and even with instinct in animals, than with their con- sciousness and intelligence. It may be said that out of one and the same property in the original protoplasm, animals have differentiated reflex action, instinct, and intelligence, while plants have developed irritability. It is only by keeping in touch with the most modern and authoritative books that the teacher can correct the older errors. PART II AN OUTLINE FOR A SYNTHETIC ELEMEN- TARY COURSE IN THE SCIENCE OF BOTANY INTRODUCTION TO PART II THE principles that have controlled the construc- tion of these outlines have been set forth fully in the preceding chapters, and in synopsis are as follows : The ideal is to guide the student to the optimum return of sound scientific training and thorough bo- tanical knowledge for the time and strength he can put into the work. They are hence a study in edu- cational economy, with three principal phases : first, the selection of the most vital and illuminating top- ics ; second, a synthetic treatment of the science, with topics arranged in such an order as to throw most light upon one another ; third, the presentation of the topics in such a form as to draw out the stu- dent's faculties the most quickly and thoroughly. They have not been worked out regardless of prac- tical considerations, but with constant account of them, and with special effort to show how the restraints imposed by them may be minimized. The general plan of the entire course is the double one used by many teachers : a first division treats of the principles of anatomy, morphology, physiol- ogy, ecology ; and a second, of the structure and '55 156 THE TEACHING BOTANIST adaptations of the principal groups of plants from the lowest Algae to the higher Phanerogams. In Division I a beginning is made with large, sim- ple, somewhat familiar objects, requiring no tools, but only the undivided attention of eye and thought. It is sought first to form the scientific instinct, — the habit of observation, comparison, and experiment. Later, the simpler tools are gradually introduced, and the less familiar materials and topics. Experiments, arranged to be tried with apparatus as simple and inexpensive as possible, are introduced along with the particular structures they throw most light upon. Every new topic is presented to the student in the form of a problem so arranged as to be solved through proper inductive processes by his own efforts. Practically, they form a series of original investigations. These problems are introduced by questions asked in a form to direct attention to the leading facts and phases of the subject. Indeed, the form of the questions is one of the most important features of such outlines as these, for they may be made to dissipate or to conserve energy, and are the chief means at command of the teacher for direct- ing observation and comparison along the most use- ful lines. It is by no means only the easiest or most familiar topics and experiments which are here rec- ommended, but a direct attack has been made upon the most fundamental and important. INTRODUCTION TO PART II 157 Since it is of the utmost importance to a proper conception of the meaning of the modern science that the student's introduction to it should be through the study of plants alive and at work, and since, in our climate and especially in city schools, much ac- curate field work is impracticable, the tracing of some living plant through its life cycle forms the best be- ginning known to me. Since plants develop from the seed with relative rapidity, and the phenomena of their growth, movements, etc., can be readily seen and experimented upon, the germination of the seed affords the best starting-point. After a single plant is thus followed through its cycle from seed to seed, the modifications of this typical form in response to different habits are taken up, and then the different members — leaf, stem, root, flower, fruit — are studied in detail as to functions, structure, and ecological modifications. Practically, most general botanical principles may be worked out best in the higher plants, because these are larger, more familiar, and easier to obtain. In Division II, living plants which may be studied alive, and even seen in their native haunts, with attention called to their habits, are used in almost every instance. With the knowledge and training ac- quired in Division I, the students work through this second division with great profit, and it is by no means inferior in value to the former. Here the 158 THE TEACHING BOTANIST lower, or cryptogamic, plants receive their proper at- tention, and here, too, is the proper place of classi- fication. In using these outlines, it is by no means expected that any teacher will try to follow them exactly ; although at the same time, in view of the amount of care, based upon much trial and experiment, which has brought them into their present form, one should have good reasons for the changes he makes. Of course many practical considerations are likely to make it impossible to provide the exact materials called for, or to take up the topics in precisely this order. Indeed, it is in general very hard to provide the materials to fit any particular set of outlines, and it is much easier and more logical to make outlines to fit the materials. These outlines are rather a se- ries of suggestions, based on considerable experience, representing useful selection and treatment of top- ics and expression of problems. They may serve as a basis or as models for the teacher in the con- struction of new outlines of his own, differing from these little or much as he pleases. Certainly, I think, a special outline should be drawn up by the teacher each week to fit his particular mode of teaching, the material available, the state of advancement of his class, etc., and a copy of this should be placed before each student who is to be held responsible for the complete working out of all that is called for INTRODUCTION TO PART II 159 upon it. Directions in some form or other must be given the students by the teacher; when spoken, some students do not hear them, others forget them, but the written outline keeps them before all. So great is the advantage of these weekly guides in economizing the teacher's time and strength, and in giving definite- ness and direction to the student's work, that there is in my experience no pedagogic device of greater worth. There is not the slightest objection to them on the score of weakening the student's self-reliance, and when given a proper form they become a great stim- ulus to him. They completely deliver the teacher from that otherwise familiar but awful question, " What do you want me to do next ? ' The experiments here given are such as seem to me indispensable. Experiments much easier to try are given in various books, but many of them are on comparatively unimportant topics ; and it is worth while to take some extra trouble to illustrate sub- jects so fundamental as those here recommended. The entire course as given in the outlines has been carefully adjusted as to time, and is worked out by my own students in a college year, with four, or some- what more, hours in the laboratory, one demonstra- tion hour, and one lecture a week. If but half, or much less, of this time can be given, the teacher will natu- rally select from the list the more important topics. DIVISION I THE PRINCIPLES OF THE SCIENCE OF BOTANY I. The Anatomy of the Seed i. a. Study the outside of the dry Lima Beans; com- pare several specimens, and observe what fea- tures are common to all and what are individual ; minutely observe : - (1) What is the typical shape? (2) What is the color? (3) What markings have they ? Answer, as far as possible, by drawings made twice the natural size ; add notes to describe features which drawing cannot express. b. Remove the coatings from soaked seeds. (1) What effect has the soaking had upon the markings, size, and shape ? (2) How many coats are there ? (3) Do the external markings bear any relation to the structures inside ? (4) What shapes have the structures inside, and how are they connected with one another ? M 161 1 62 THE TEACHING BOTANIST Answer as before by drawings and notes, the former natural size. 2. Study fully in the same way the Horse Bean. 3. In a concise paragraph describe the resemblances and the differences of the Lima and the Horse Beans. Materials. - - White Lima Beans (Phaseolus lunatus) and Horse Beans (Vicia fab a equina), about six to a student, may be bought in all large seed stores ; half should be soaked over night. Windsor Beans may be used in place of the Horse Beans, and other kinds will do ; but those selected should be large, and such that in one the cotyledons come above ground in germination, and in the other they remain below. Pedagogics. - -This outline can be completed by the average student in two two-hour periods, but three are much better ; if necessary, Exercise 3 can be completed at home from their drawings and notes, but it is better worked out with the seeds in hand. No tools except a pocket knife are needed, not even a lens. In a large laboratory division general guidance to the whole class, as well as individual help, not too much of either at first, should be given, as recommended in Chapter III. The exercises in this outline are principally to teach beginners : - (I) To see a natural object as it is, correctly and com- pletely. (II) Through comparison to eliminate accidental and indi- vidual features, and thus to distinguish essential from unessen- tial characters. (III) To represent clearly to another what is seen, for this purpose using words or drawings according as the one or the other is the more expressive. (IV) A knowledge of the anatomy of some typical seeds. ^ ANATOMY OF THE SEED 163 Following are points of importance in the teaching of these four essentials : - (1) On Observation.- -It is of first importance that the stu- dent learn to see natural facts absolutely as such, uninfluenced by any explanation of them. Hence he should be kept at work upon the Lima Beans until he has clearly seen (as shown by his drawings and notes, and under questioning) which of his specimens are average or most typical ; what their shape and color is ; the radiating markings, stopping short of the edge ; faint concentric markings (not always visible) ; on the concave edge a large scar, at one end of which is a tiny pit, and at the other a tiny raised yellowish triangle, which con- tinues into a faint ridge ending in a more raised portion, the latter making an angle as seen from the side. Observation consists not only in seeing all these things, but in seeing them in their proper relative positions and connections. Names and uses should not be given until after the things have been seen, some curiosity aroused as to their use, and a need felt for names for them. On removing the seed-coat, the student should' see that this is single (actually two united, though usually he cannot see that) ; also the thick line representing the ridge he saw out- side ; and the lack of any connection between exterior mark- ings and the structures inside, excepting only the position of the micropyle over the end of the hypocotyl (not of course at first using those terms). In the embryo he should see that hypocotyl and epicotyl are united, one the continuation of the other ; that the cotyledons are lateral growths of the hypocotyl ; and that the plumule consists of a short stalk bearing two folded veined leaves, one partially enclosed in the other. (2) On Comparison.- -The student should see that some 1 64 THE TEACHING BOTANIST cracks and folds are simply due to individual differences in the mode of drying, etc., and that shape and size are variable, though within limits. In his treatment of Exercise 3 he should be led to distinguish clearly resemblances and differences, and to describe them separately. (3) On Representation.- -The general principles of this part of the work are discussed in Chapter IV. Observation should be fully made before recording is begun. As to draw- ing, the students should first be allowed to do the best they can unaided, judging for themselves how many and what kind of drawings are necessary to show completely the seed and its parts. They should be made to complete a subject the best they can before it is examined or criticised by the teacher ; this is to inculcate self-reliance. After they have done their very best, their work should at once be examined, and wherever it shows marked deficiencies they should be encouraged to look and try again. After they have finally done all they can, the teacher should, step by step, carefully explaining the logic of each point, show them the best way he knows for representing the objects, with which they may compare their own efforts ; this may well be done for them all together on a blackboard ; they are, after their own trials, in a position to profit by all of the advice thus given. A good representation of the Lima Bean as an example for beginners is shown in Fig. 12, though the faint radiating lines might have been added. But while representation is made thus important, the teacher must not go so far as to make a fetich of it ; for after all it is but a means to an end. At first only clear diagrams should be insisted upon - - shading, etc., may better come later. It is, moreover, very important not to insist upon too many things at once, as this tends but to confusion ; earlier exercises may well be left somewhat incomplete for this reason. The descrip- ANATOMY OF THE SEED i6S tions in words should be studies in clearness and conciseness ; but perfection cannot be expected at the start. From the first, rough sketches should be forbidden. Few drawings may be raphe FlG. 12. — Good drawing, by a beginner, of Lima Bean, X i£. made, but in these every line and spot should have its mean- ing, and nothing admitted for which there is not an equivalent in the seed. Outlines should be firm, clear, and complete, and haziness not permitted. The drawings should not be a com- posite made up from several specimens, but an accurate draw- ing of a typical specimen. (4) On gaining Knowledge of Seed Anatomy. — Their obser- vation gives them the lead- ing facts of seed structure. After they have seen and represented the structures, the teacher should lead them (using the blackboard while showing them better W •-caulicl --cotyledons- of drawing) to ask FIG. 13. — Good drawing, by a beginner, of What is the Use Or Other embryo of Lima Bean. Actual size. meaning of each part ; and as they have no data for deter- mining any of these, except, perhaps, the hilum, the early 1 66 THE TEACHING BOTANIST life and development of the seed must be briefly described to them with reference to the use of each part. This applies in particular to the markings ; the use of parts of the embryo they will learn for themselves later. Along with this, and after making them feel the need for single terms to describe the different features, the proper names may be given them for the parts, and these terms may be the better impressed upon them if accompanied by side remarks upon their etymology, etc. Of course names and uses should be carefully recorded. Terms needed are Coats, Hilum, Micropyle (Strophiole, very small in bean), Raphe, Chalaza, Embryo, Cotyledons, Hypo- ,..blurnule SCQTO/ cotyledon •-c.au title co.ttj/edons FIG. 14. — Good drawing, by a beginner, of embryo of Lima Bean laid open. Actual size. cotyl (or Caulicle), Plumule. (Of course the chalaza itself does not appear in the seed, but its position is shown by a slight projection or angle, which may be called the " chalazal angle.") The names may be added as shown in Figs. 12, 13, 14. The teacher will do well to work up for himself the develop- ment of the ovule in the Bean, which can very easily be done from String Beans of different sizes. By a series of outline diagrams he can then make clear to the class the exact mean- ing of the peculiarities of form and markings in the seed. This would form an excellent topic for investigation by some of the brightest pupils. MORPHOLOGY OF THE SEED 167 II. The Anatomy and Morphology of the Seed 4. a. Study the outside of the Horse-chestnut (a typical specimen), and minutely observe : - What is its shape, its color, and its markings ? Does it show any feature not in the Beans ? Answer, as before, by drawings and notes. Select for yourself the best scale. b. Remove the coatings from a soaked seed, and observe : — (1) How many coats are there, and how are the markings related to struc- tures inside ? (2) What shapes have the internal parts, and how are they connected with one another ? (3) Are there any new parts or features not present in those already studied ? Answer, as before, by drawings and notes. Care- fully separate with the fingers all parts that can be forced apart without tearing. 5. In a similar way study the seed of the Morning- glory. 6. In a similar way study the grains of Corn. Where parts cling too closely to be separated by the fingers, use a knife, and try clean median sections. 1 68 THE TEACHING BOTANIST 7. a. In a concise and tabular form, compare as to the chief resemblances and differences the four kinds of seed you have studied, - - the Bean, Horse-chestnut, Morning-glory, and Corn. b. Construct a series of four diagrams, showing by corresponding colors the relative development of the equivalent parts in the four embryos. (Place this series on the upper half of one page, and leave the remainder for a related series to come later.) Materials. — The Horse-chestnuts should be soaked for a week ; if then the cotyledons do not separate readily, immer- sion in hot (not boiling) water for a few minutes will make them. For the purposes of this exercise it is a most valuable seed, and every effort should be made to obtain it. Morning- glory seeds, the largest size, which may be bought cheaply by the ounce in seed stores, should be soaked only four hours. Though this seed is small, it is hard to find a larger one which is as instructive. The Castor Bean (Ricinus} germinates badly, and hence cannot be followed into its later stages, while Four- o-clock is puzzling through presence of the fruit. A lens will make the Morning-glory sufficiently clear. Corn, soaked over night, must be studied chiefly by sections. Pedagogics. - - This outline will require at least three two- hour periods, with some outside work. Its object is to continue training in observation, and to form an introduction to morphology. As to observation, after their previous experience, the students will readily find in the Horse- chestnut everything on the seed-coats, including the fibre-vas- cular bundles on the hilum. The coats are two united, but MORPHOLOGY OF THE SEED 169 will seem to them as one. They should see that the hypocotyl does not lie against the cotyledons as in the Bean, but is sepa- * rated from them in part by a seeming pocket of the coats (really due to a folding of the young ovule enclosing part of the coats) ; and that the seeming hypocotyl really splits down part of its length and has the plumule at the bottom of the split. In the Morning-glory they should find (with help of a lens) micropyle and raphe as well as hilum, and the jelly-like endosperm and the two cotyledons. In the Com they should see, in addition to the other parts, the remnant of the silk (style) and the leaves of the plumule, on a failure to see which they should be reminded, not simply to look at things, but also to move and separate them. Of the utmost importance in biology is morphology. Prac- tically, it consists chiefly in recognizing the original nature of parts, no matter how much disguised by changes of size and shape. Its best index is the relative positions of parts. The Horse-chestnut is good to begin with, for the student may be made to work out for himself, by careful comparison with the construction of the embryo in the Bean, that what he at first always takes for " hypocotyl hollowed out with the plumule at the bottom," is really largely stalks of the cotyledons, while the hypocotyl is only the part below the plumule. In the Morning-glory he is apt at first to mistake the very leafy cotyle- dons for plumule, but can be led to work out their true nature. And in the Corn he can thus discover that the shield-like body is cotyledon. (Actually there is some slight doubt on this point among experts, but it is probably true, and can be so treated, with a caution to the students.) The observation of the remnant of the style on the corn grain, and their ina- bility to find any equivalent for it on the other seeds, may be used to introduce an explanation of the composition of this I/O THE TEACHING BOTANIST grain as ovary united to seed ; and they may be led to notice that the micropyle is not present, and that the scar of attach- ment, while functionally a hilum, is not strictly so morpho- logically. The occurrence of food substance outside of the embryo in Morning-glory and Corn should be used to make them seek for it in Beans and Horse-chestnut, and thus to work out the differences between " albuminous >: and " ex- albuminous" seeds. FIG. 15. — Diagrammatic figures of embryos of Lima Bean, Morning-glory, Horse-chestnut, and Corn, shaded to show morphologically equivalent parts. Diagonal lines = hypocotyl ; vertical lines = cotyledons ; dots = plumule; circles = food substance. Of the greatest morphological value is the Exercise 7 which is one of the best I have ever tried for inculcating a true idea of morphology, the more especially when combined with similar diagrams of germinated stages of the same seeds. In making these diagrams all unessentials should be omitted, and an effort made to represent only the principal correspond- ing parts placed in corresponding positions. The diagrams should be somewhat as illustrated in Fig. 15, except that the equivalent parts can be brought out much better by colored MORPHOLOGY OF THE SEED I /I crayons than by the black and white lines here made neces- sary by the method of engraving. The food substance may be represented by small circles of blue, or of some other color. In 7 (a) they should not run to details of little importance, and resemblances should be emphasized as well as differences. About this time a tendency will manifest itself to turn the precious laboratory hours into a drawing lesson ; this must be firmly met by making it plain that the laboratory time is for observation and essentials of recording, and that all niceties must be added in outside time, though rapid workers may naturally be permitted some liberty in this respect. No new terms are needed except endosperm and albumen, the latter only in connection with the compounds " albumi- nous" and " ex-albuminous" It is best not to give at all any terms of very limited application, such as " scutellum." As to tools, a knife or scalpel may be used for sectioning, and a lens for the Morning-glory (after they have tried to work without it) . Tools and terms should be given only after students have been made to feel the need for them. While the subject of the structure of the seed is fresh in memory it will be well for them to read the very fine chapter on this subject in either of Dr. Gray's text-books. Many additional exercises on seeds are outlined in Spalding's and in SetchelFs books ; and if other materials for the next following exercises are wanting, or some students manifest a special interest in the subject, these may well be introduced. But for most students it is more profitable to pass on to other subjects than to spend additional time upon this. Considerable simple physiological experimentation upon the growth of seeds in relation to temperature, light, moisture, and oxygen, is possible, and described in Bergen's Botany. Most of these facts thus proved, however, are not specially characteristic of seeds, but THE TEACHING BOTANIST apply to other stages of growth as well. A study of the storage of nourishment in seeds is important, a subject well treated in Bergen. III. The Locomotion of Seeds 8. The seed is the locomotive stage of the plant. Seeds have no power of independent movement, and hence can secure locomotion only through being carried by some of the moving agencies of nature. To fit them thus to be carried, adap- tively constructed appendages have been de- veloped. a. What are the different moving agencies of nature which can carry seeds ? b. Study the ten seeds supplied to you. In each case find out and record : — (1) What part produces the special appendages ? (2) To what moving agency are the appendages probably adapted ? (3) What accessory features of shape, weight, etc., to aid the appen- dages, are found in the seed itself ? Make only outline sketches fully labelled. 9. Write a concise essay (of not more than two hun- dred and fifty words) upon the principles, deduced • from your laboratory work, from the lectures, and LOCOMOTION OF SEEDS 1/3 from your reading, of the anatomy, morphology, and ecology of the seed. This is to be handed in (here the date). Essays are to be written in ink in the Essay Book only. Each is to be preceded by a tabular out- line of its contents. Materials. — These must chiefly be collected beforehand in the summer. Good ones are Maple, Asclepias, Agrimony, Spruce or Pine, Desmodium, Ptelea, Elm, Xanthium, Burdock, Bidens, Dandelion, Tecoma or Catalpa, Galium, Castor Bean, Geranium maculatum. It is desirable to have, as in this list, some seeds and some " fruits." The museum collection, in- cluding some of the more remarkable kinds, will here be very valuable. The use of berries and other pulpy fruits should be explained by the teacher, since it could hardly be imagined from laboratory study; their morphology more properly comes later in the section " Fruits." Pedagogics. — This exercise is for further training in obser- vation, comparison (morphology), and for an introduction to ecology (i.e. adaptation to conditions of the external world). In morphology the student should trace out from exactly what part the appendage is developed, whether from seed-coat, ovary, style, or calyx. To aid in this, the teacher must give some account of the structure of the flower and fruit. To distinguish whether a given structure is seed-coat or ovary, dissection will be necessary. He will thus discover that what are ecologically the same structures may have very different morphological* origins ; from which he should be led, after the ecological use of the parts has been learned, to infer the great importance of function in developing structures. THE TEACHING BOTANIST In ecology, since the study is in the laboratory, and not out of doors (as it would much better be), the students can do little better than guess at the use of the different appendages. They can, however, be much helped by recalling facts already known by observation, as to the carrying of maple, willow, and other seeds and fruits by wind, and the sticking of seeds to their clothes in their walks through pastures, and also by some simple experiments, suggested by the teacher, upon the differ- ent seeds in the laboratory. This work will give them an introduction to theorizing- -a habit of the greatest value in biology if kept checked by rigid observation or other confir- mation, and of the greatest disaster if allowed to become merely untested guessing. In this case, since confirmation from outdoor observation is impracticable, the correctness of their theories will need to be tested by reference to the teacher, who should be thoroughly informed upon the subject ; but it should be made plain that the teacher's knowledge is not better than their own observation, but only a substitute en- forced by circumstances. In Exercise 8 (a] the students will think of wind, animals, and probably water- currents, to which hints from the teacher may cause them to add throwing by spring- apparatus, which include all of importance. In their drawings the important locomotive appendages should be clearly brought out ; for example, in the Burdock, half of the students will not represent the hooked tips, though they are plainly visible ; in such cases they should individually be told they have missed something important, and left to seek until they have found and correctly represented it. A fully illustrated account of this very important subject of seed locomotion, one of the most interesting of all botanical topics to most people, should be given in a talk or lecture. LOCOMOTION OF SEEDS 175 Books relating to it may be found cited in Chapter VII. Other adaptations in seeds may also be taken up, such as their protection against animals until ripe ; how they absorb water ; how some seeds plant themselves, etc. For the essay on the seed, consult the advice in Chapter IV. It is convenient to have a special book for the essays, uniform with the laboratory book. After they have done their best on this essay, it is well to read them one written by the teacher as a model. Following is one I have read for this purpose to my students : — THE SEED General Function. Structure, — Coats, Embryo, Endosperm. Locomotion. The seed is a portion of plant substance specialized for reproduction and locomotion. Under a great variety of forms, sizes, and colors, seeds have in common the coats, embryo, and endosperm. The coats, one or two, are protective, and the outer usually shows the scar of attachment to the pod (hilum), a pit by which the fertilizing pollen tube entered (micropyle), and a ridge through which the nourishment was distributed (raphe and chalaza). The embryo is the young plant, and consists of stem (hypocotyl), on which are placed laterally one or two leaves (cotyledons), and which merges upwards into the bud (plumule). The endosperm may be stored in the cotyledons, making them thick, or around them, or in both ways. Locomotion is as essential to plants as to animals, and since the adults cannot move, the seed is generally used as the locomotive stage, and to it appendages are added to cause it to be carried by some of the natural moving agencies. These 1/6 THE TEACHING BOTANIST appendages may be outgrowths of the seed-coat, or of ovary, style, or calyx, retained for the purpose. They may consist of wings or plumes to utilize the wind, hooks for attachment to the fur of animals, pulp to be eaten by animals, or may be absent altogether, in which case the seeds are often projected by the springing of elastic tissues. IV. The Germination of the Seed and Growth of the Embryo 10. Study the germinating Lima Beans, and, in com- parison with your records of the ungerminated bean, observe : - (1) Whether all seeds have developed at the same rate. If not, why not ? (2) Where and by what force has the coat been burst ? (3) What change has occurred in the food substance ? (4) What changes of shape and size have occurred in the parts originally in the seed ? (5) Have any new parts appeared? (6) Does hypocotyl or plumule develop most rapidly ? Why ? (7) What directions do hypocotyl and plu- mule take in development, relatively to: — GERMINATION OF THE SEED 177 (a) The position of the seed as planted ? ($) Any feature of the environment ? (8) What are the relative positions of main and side roots ? Answer by a fully labelled sketch of a typical specimen, and, where necessary, concisely in words. 11. Study in the same manner the germinating Horse Bean. 12. Study in the same manner the germinating Morn- ing-glory. 1-3. Study in the same manner the germinating Corn. 14. Select any one of the above kinds of seeds, and make a series of outline drawings to illustrate Exercise 10 (7). 15. Your studies (Exercises 10 (7) and 14) have shown you that the positions taken by hypocotyl and plumule in growth are entirely independent of the position of the seed from which they came. Their up-and-down position suggests that gravi- tation may have something to do with it. To test this, the logical plan is to place two sets of seeds under conditions precisely alike, except that gravitation is allowed to act upon one set and not upon the other. Since, however, nothing upon the earth can be removed from the influ- ence of gravitation, it is necessary so to arrange N 1/8 THE TEACHING BOTANIST one set that gravitation may be made to neu- tralize its own effects. This has been done in Experiment i, in which the two sets of seeds are under the same conditions of temperature, light, moisture, food supply, and differ only in their relation to gravitation. a. Has gravitation anything to do with the posi- tion taken by hypocotyl and plumule in their growth from the seed ? Answer by observation of Experiment i. All records of experiments should bring out clearly : — (1) Object of the experiment. (2) Method and appliances used. (3) Exact results observed. (4) Conclusions. b. In precisely what way does gravitation act to influence the up-and-down position ? c. Express synoptically your conclusions upon these points : - (1) For what good do stems grow up and roots grow down ? (2) By what influence are they guided into those positions ? (3) By what mechanical means are they brought around into those positions ? (4) Why is gravitation thus used instead of other external influences ? GERMINATION OF THE SEED 179 Materials.- -The seeds may best be germinated in wooden boxes in chopped Sphagnum moss ; a greenhouse at a day temperature of 70° is best, and without bottom heat, which makes the roots too slender. These seeds can also be grown easily in the Wardian case (see page 85). Lima Bean and Morning-glory grow faster than the other two, which must be planted two or three days earlier. Six to eight days will bring them into good condition ; the best state is that in which the hypocotyl and root are about one to two inches long. The FlG. 16. — Box with sloping glass front for germination of seeds. X\. germinating seeds should, of course, be given alive and grow- ing to the students ; hence they should be planted in many small boxes, one to as few students as possible. After many trials I have adopted the following plan : wooden boxes are used, of the shape and size shown in Fig. 16, eight inches long by six wide and five deep, painted for preservation, and with one sloping side of glass slipped into a groove and protected above by a strip of wood ; the four kinds of seeds are planted in chopped Sphagnum, in as different positions as possible, eight of each kind in each box. The Lima Beans are planted l8o THE TEACHING BOTANIST against the glass, and, growing against it in their descent, show the positions and mode of branching of the roots most beauti- fully. One of these boxes is supplied to each student, who uses about half of the material, and has it again for the work of the next week, the box in the meantime being returned to the greenhouse, and the seedlings grown on as far as possible. The boxes, if made in quantity at a box factory, cost complete about 12 cents each, and of course can be used many years. The value of supplying to each student his own set of living and growing specimens in a box so arranged as to show the under-ground as well as above-ground parts, is very great, and amply worth the cost and trouble. If this system is not used, the teacher should have some seeds grown in one such box for all the students to see. The advantage of using the moss instead of earth is obvious ; it is lighter and cleaner, and the specimens can be removed from it without injury. Pedagogics. — This outline can be completed in three two- hour periods. It is to continue training in observation and comparison, but especially is an introduction to the morpho- logical and ecological principles controlling the unfolding of the seed into the adult plant, and (most important of all) is an introduction to the nature of irritability, which in plants answers to sensation in animals. The students should not fail to notice that the root, the root hairs, the turning green of parts exposed to light, the axil- lary buds of the cotyledons in the brown bean, and the partial disappearance of food substance are new features. They should especially see that it is the elongation of the hypocotyl which raises the cotyledons in Lima Bean and Morning-glory, while it does not increase at all in length in the Horse Bean and Corn. The root is, of course, a new structure developed from the lower end of the hypocotyl, and its beginning is usually GERMINATION OF THE SEED l8l marked by a slight constriction or by the first side roots. Students will tend to call the main root hypocotyl, and to call only the side branches "roots," which must be corrected. The structure of the root, including the tips and root hairs, is very plainly seen through the glass, especially by use of a lens, and should be well worked out. Full labelling, to bring out the homologous parts, is very important. In facts of ecology, they will notice that root grows faster than plumule (of course because absorption of moisture is a first need), and that size of seed, position in which planted, amount of moisture, all have something to do with the dif- ferent rates of development of the same kinds of seeds, to which some students will probably add a real difference in their living matter, which is strictly true. We have here an introduction to facts of individual variation, so important in evolution. From some of each of the kinds in the boxes, the young plumules should be pinched off, the results to be noted the next week. It would be of interest also in this connection to study the germination of Horse-chestnut, but practically it is very diffi- cult to germinate. They will, of course, readily notice in Exercise 10 (7) that the position taken by hypocotyl and plumule (or rather epi- cotyl), in growth, bears no relation whatsoever to the position of the seed, but that, regardless of this, all hypocotyls bearing the roots grow down, and all plumules grow up. They should then be led to ask what determines this up-and-down position (that is, how does the young plant know which is up, and which is down), whether darkness below, or the moisture, or something else ; they may be encouraged to experiment upon these, and then their minds will be in condition to appreciate the results of Exercise 15. 1 82 THE TEACHING BOTANIST Other topics of interest and value on germination are : — How the seed-coats are burst in different seeds. How the embryo breaks out of the ground. How the embryos fasten themselves to the ground to give a resistance to enable the hypocotyl to bore into the ground. The behavior of the food substance in germination. Experiment No. i . — This experiment is of the utmost impor- tance, since it gives a logical understanding of the true nature of geotropism, a typical form of irritability, and one of the easiest to understand. If geotropism is once understood, it will make all other forms of irritability easily comprehended. Irritabil- ity in plants answers to sensation in animals, and a clear con- ception of it is essential to the understanding of the most important peculiarities of plant form, movements, and adapta- tion of the individual to its environment. I believe that one of the greatest advances that could be made toward placing the teaching of Botany upon a truly scientific basis would be through the introduction into it of a correct teaching of irrita- bility. Of course the teacher must first be trained, or train himself, in this vital subject. Experiment i can be performed very satisfactorily, as fol- lows : Pin to each of two corks, five inches in extreme diameter and one inch thickness, five or six soaked Horse Beans in as different positions as possible, though alike on the two corks. Slip the Beans out to the heads of the pins a half inch or more from the corks. Place around, over, and under them clean, moist, chopped Sphagnum moss, and then fit over the corks thin crystallizing dishes (see Fig. 17), about two and a quarter inches deep, and wide enough to just hold well on the bevelled edges of the corks when these are pushed into them (i.e. four GERMINATION OF THE SEED 183 and a half inches in diameter). Set one cork upright in a fixed position ; push the horizontal rod of a clinostat into a hole previously made in the middle of the other, so it will be kept revolving slowly in a vertical plane. The Beans on the fixed cork will, in three or four days, all have roots turned downward, while on the revolving cork they are at any and all angles, but usually somewhat in the direction they have in the seeds. It is well to keep them covered from light FIG. 17. — A simple clinostat. x |. by black paper, but while under observation by the students the moss may be removed and the glass cleaned and replaced. Using the Horse Beans, which are the best known to me for such purposes, this experiment is, with me, always highly satisfactory. The crystallizing dishes may be omitted, in which case occasional watering is needed, and the moss must be tied to the corks, or aluminum dishes could be used. Unfortunately, the only clinostats on the market are expen- sive. Wortmann's is the best ; it costs duty-free about $50, and 1 84 THE TEACHING BOTANIST must be imported from Germany by one of the dealers in labor- atory supplies (see page 93). It is useful for many purposes, however, and is a profitable investment. I have made a fair substitute, as follows : buy a Seth Thomas eight-day clock, cost about $5 ; have a watchmaker alter the wheels so that the spindle of the minute-hand will make a revolution in about fifteen minutes (rendered necessary by the shortness of " re- action time ") ; this can be done by shortening the hair-spring and removing each alternate tooth from the escapement wheel ; let him make a brass disk two inches in diameter, with holes on its edge, and an arm to slip over the spindle, so that the disk will revolve parallel to the face of the clock. To this disk may then be fastened, by tacks through the holes, a cork bearing the seeds, as recommended above (Fig. 17). Such a clinostat will not carry large flower-pots, but seeds and seed- lings grown in moss show the principle of irritability as well as potted plants. From observation of this experiment, in which the two sets of seeds are under precisely the same external conditions in every respect except in their relations to gravitation, students should be able to deduce the fact that gravitation is a determining in- fluence in giving the up-and-down position to the developing plumules and roots. Since, however, parts grow up against gravitation as well as down with it, it cannot act simply as " weight," but can only serve as a guide or index of direction. The teacher will have to explain that the movement of the growing parts around into the vertical position is brought about by one-sided growth, a subject very easily illustrated by experi- ment. Gradually the students may be brought to recognize in the process the three elements: (i) an hereditary knowledge (as it were) in the embryo of the advantageousness of sending stems up and roots down; (2) a power of perceiving from the GERMINATION OF THE SEED 185 pull of gravitation, which is up and which is down ; and (3) the use of processes of growth in such a way as to bring the parts around into the up-and-down position. A fair simile helping to make the process clear is that of a sailor starting to cross the ocean, steering by compass. Here, too, are the three elements: (i) the sailor knows to what port it is to his interest to go ; (2) he perceives by observation of the compass which is the proper direction for him to take; (3) he so ad- justs his mechanism of rudder and steam, or sails, as to take him to his destination. The plant uses the pull of gravitation as the sailor uses the compass, purely as an index to direction, and gravitation no more pulls the plant into the up-and-down position than the compass pulls the sailor north and south. In both cases it is previous experience which gives the knowledge of the proper direction to be taken ; in both cases there is use of a guide to show which is the direction ; and in both cases there is a motive mechanism to carry them into the advanta- geous position. Later studies will prove to the students that gravitation is not only used as a guide to the up-and-down direc- tion, but also as a guide to lateral directions, as in lateral roots and stems, and in many creeping stems and climbing roots ; here, too, the analogy with the compass holds, for the sailor need not go north or south as the needle points, but at any angle between which it is his interest to take, and the compass guides him as well east or west, though it points north and south ; and this is true, also, of gravitation with the plant. The reason why gravitation is used as a guide instead of light (by the stems), or moisture, etc. (by the roots), which also would guide those parts into the proper directions is, no doubt, this, that gravitation acts in the proper direction, with constant intensity, and at all times, while all of the other influences vary in direc- tion, and are sometimes altogether absent. 1 86 THE TEACHING BOTANIST In geotropis'ii there are many additional experiments very easy to try, and very instructive. For example, while the side roots are growing, the germination box may be tipped up through 45° in a vertical plane, when a beautiful response to the changed direction takes place ; to show that the upward growth of stem is geotropic, a small plant may be placed on its side in darkness for a day ; also plant a Bean in a small pot of Sphagnum moss, and after it is well up, turn pot and all upside down, and support it in that position for two or three days, after which the moss is to be removed. A most valuable experiment, proving that growth is concerned in bringing roots into the vertical position, is as follows : — Place a soaked Horse Bean in moist Sphagnum moss, with its hypocotyl pointing downward ; after the root has grown one inch long, remove it, and, keeping it from drying in the process, mark rings a millimetre apart upon it, from end to end, with waterproof India ink. This may best be done by a thread moistened with the ink and kept stretched on a spring made of wire. Replace the seed in the moss with the root horizontal, and, after it has again turned downward, note the position of the rings. If students are not satisfied that gravitation is the guide to direction in ordinary plants, but think that it may be moisture which guides the roots into the soil, or light which guides the stems upward, etc., very simple experiments may be invented to prove that these influences do not thus act. Thus, light may be thrown upward upon a plant, turned upside down, by means of a mirror, the plant being covered with a dark box above. Again, seeds may be placed in the centre of a large box of Sphagnum, and watered from above ; and other experiments equally simple may be devised by the teacher to meet each point. DEVELOPMENT OF THE SEEDLING 187 V. The Structure and Development of the Seedling 1 6. Study, at every step in comparison with your records of the earlier stages, the seedling of the Lima Bean. (1) Into what has each part of the original embryo developed ? (2) Are there any new parts not originally in the embryo ? (3) How are the new leaves placed rela- tively to the cotyledons and to one another ? (4) How do the later leaves differ from the earlier ? (5) How many buds are there, and where are they ? (6) Where does hypocotyl end and root begin ? (7) Is there any regularity about the ar- rangement of new roots as there is about new leaves ? Answer by an annoted sketch, bringing out the above points. The labelling should express clearly the morphology. 17. After the same manner study the Horse Bean seedling. I 88 THE TEACHING BOTANIST (1) Why do the cotyledons remain below ground in this Bean, and rise above it in the Lima Bean ? (2) What effect is produced by this differ- ence upon the growth of the hypo- cotyls ? (3) Where is the terminal bud which con- tinues the growth of the stem ? 1 8. After the same manner study the Morning-glory seedling. Why does the plumule develop so late ? 19. After the same manner study the Corn seedling. From what parts do the upper roots come ? Is there anything similar in adult Corn plants ? 20. From your observations deduce the morphological nature of hypocotyl, cotyledon, and plumule. Express in a sentence. 21. Construct a series of four generalized diagrams of the seedlings studied, expressing in colors (identical with those used in Exercise 7) the comparative morphology of the four seedlings, in comparison, with one another and with the seeds from which they grew. (Place if possible on the same page with those of Exercise 7.) 22. You have observed in your boxes of seedlings the turning of the plants toward the lightest side ; and this turning toward the light is very DEVELOPMENT OF THE SEEDLING 189 well known to you in house plants in windows. The constancy of this turning suggests that light-direction must determine it. To test this, the influence of one-sided light must be removed. This may be done either by placing the plant in the dark (which, however, introduces abnor- mal conditions), or else by making it revolve so that one-sided light is made to neutralize its own effects. The latter has been done in • Experiment 2. (1) Is light-direction a determinant of bend- ing of green leaves and stems ? An- swer by observation of Experiment 2. (2) Is the process of turning (called helio- tropism) analogous to geotropism ? (3) For what good do leaves and stems turn toward the light ? (4) Do leaves and stems behave alike as to the positions they take relatively to light-direction ? Materials. — Either seedlings remaining in the boxes of last week, or, since they can hardly grow enough in a week, others grown on in ordinary boxes ; they are most useful if the third and fourth leaves show. It is well to grow some of them in the Wardian case, so the students can watch their development. Pedagogics. — This exercise (needing at least three two-hour periods) is for further training in observation and morphology, 190 THE TEACHING BOTANIST but it is especially for the observation of ecological and physiological phenomena, and the use of experiment in their interpretation. In observation, they should not fail of themselves to see and record, in addition to the more obvious features, the axil- lary buds of the cotyledons of the Beans, stipules on the Lima Bean (united in pairs at the first leaves), the arrange- ment of the earlier roots in four ranks (answering to their origin from the four fibro-vascular bundles), and the fact that leaf veins taper from base to tip, and are all united with one another. The position of the terminal bud in the Horse Bean should also be seen correctly. Exercise 20 is most important to compel clearness in mor- phological ideas, as is particularly Exercise 21. In ecology they may be led to see that the failure of cotyledons to come above ground in two of the seedlings is due to their lack of usefulness as leaves on account of their shape. In the Morning-glory, the small supply of nourishment in the seed explains the late appearance of the plumule ; the material to make it must first be formed in the green cotyle- dons. Most students can recall the roots from joints above ground in adult Corn plants. They should be encouraged always to call to their aid any previous knowledge of this kind which they may possess. Experiment No. 2. --In preparation for this the teacher will do well to direct the students' attention beforehand to the obvious cases of turning toward light in the boxes of seedlings, and the cases known to all of them in house plants. Two simple and similar plants in small pots should be taken (Tropicolum, i.e. "Nasturtium," is very good). They should be placed in strong one-sided light, but one of them should be kept revolving in a horizontal plane on a clinostat. Of THE DIFFERENTIATED PLANT 191 course if a Wortmann or other large clinostat is available, plants of any size may be used ; but if only the small clino- stat made from a clock, as recommended for geotropism ex- periments (page 184), is at hand, then a very light flower-pot, preferably not over three inches in diameter, is needed, and seedlings growing in Sphagnum moss may be used. Numerous supplementary experiments may be tried, such as allowing the parts to become turned to light, and then exactly reversing them by turning the pot through 180°. Indeed, this simple experiment is almost as satisfactory as the clinostat. Again, the negative heliotropism of roots may very easily be illustrated by the familiar experiment given in most books (as in MacDougal's Physiology, page 59, Fig. 54). Observation of their experiments and of other cases should lead students to see for themselves that stems turn into the line of the light, while leaves turn at right angles to it, and they can easily be led to see the meaning of this : the light being necessary to the leaves, they expose their flat surfaces to it, while the stems take that direction to help expose the surfaces of the leaves. The very close analogy of the process with geotropism should be emphasized. VI. The Differentiated Higher Plant 23. Study the Bean plant, a well-differentiated plant. Observe every constant external feature, and properly record. Finally, remove it from the pot, wash away the soil, and observe the structure of the roots. 24. In comparison with the Bean, observe fully the Coleus and the Balsam (Impatiens). (It is not THE TEACHING BOTANIST necessary to make full records for them.) By comparison of the three plants determine, and express in words : — (1) Have leaf and bud any constant rela- tionship of position ? (2) In what positions do flowers (or fruit) originate ? (3) Do leaves and stem increase in size in some special part, or through their entire extent ? (4) Is there any regularity in the position of origin of leaves on the stem ? (Invent simple and logical diagrams to show the leaf arrangement in the three plants.) (5) In what positions do new roots origi- nate ? 25. Diagram the geotropism of the Coleus shoot. In one diagram express the ideal arrangement, and in another its disturbance by light from one side. 26. In growth, such as you have been studying, very important physiological processes occur. From common observation and experience, which may be tested by simple experiments, every one knows that warmth and moisture are necessary to all stages of growth, including germination of seeds. Particularly important, in growth as in many other physiological processes, is its rela- THE DIFFERENTIATED PLANT 193 tion to the two gases, oxygen and carbon dioxide. This relation may best be investigated in the germination of seeds, since there it is least complicated by other processes. (1) Is oxygen necessary for the germination of seeds ? This can be answered by an experiment in which a comparison may be made between one set of seeds supplied with oxygen, and an- other set deprived of it. This has been done in Experiment 3, in which oxygen is left in the two tubes con- taining the clear liquids, and absorbed by pyrogallic acid and potash in the other. Minutely observe this. (2) When one of these gases is absorbed, the other is usually given off. Is carbon dioxide given off in growth ? This may be answered by an experi- ment in which a liquid capable of absorbing carbon dioxide (such as caustic potash) is so placed that it will rise in a tube as it absorbs that gas from a closed space. This has been done in Experiment 3 in one of the tubes containing the clear liquid. The third tube contains simply water. (3) Is this process like anything in animals? IQ4 THE TEACHING BOTANIST (4) What is the primary meaning and use of this process in the plant ? Has it the same meaning in the animal ? Your record of (i) and (2) above is to be worked out as in Exercise 15 (a). 27. Prepare a synoptical essay (not over three hundred words) upon the Germination of the Seed and the Growth of the Embryo into the Adult Plant. To be handed in (here the date). Materials. -- Bush Beans (Phaseohis vit/garis, var. Golden Wax) are very easily grown, one in a pot, and may be brought into flower and fruit in about six weeks. Lima and Horse Beans grow so large they are unmanageable. Of course other plants may be used, but the advantage of following some one kind of plant through its entire cycle is very great, and the Bean shows a particularly large number of important features. One plant will do for several students, though the ideal is one to a student. It is easy to obtain others from florists for comparison, and Coleus and Balsam (Jmpdtiens siiltani} are particularly good, though others will do ; one or two of each of these would be enough for a class. Pedagogics.- -This exercise, in addition to training as be- fore, is intended to give a clear idea of the morphological composition of the higher plant, and also of the nature of the process of respiration. As to observation, having reached this stage, the student should be able to work out and show the con- stant features of fairly complex structures fully and correctly, and to represent them well. He should not miss the pulvinus of the leaves nor the stipels, nor the very important nodules on the roots, nor the calyx and bracts on the fruit. In morphol- THE DIFFERENTIATED PLANT 195 ogy he should note that flowers (and fruits) originate where buds do ; that new parts come either from terminal or axillary buds and that buds produce stems bearing leaves as lateral out- growths. If allowed to follow his own observations to their conclusions, and not forced into seeing what is not there, he will find that the plant, so far from consisting of a series of joints (phytomera) springing one out of another, grows from contin- ually advancing buds which put out the leaves laterally and branch in the axils of these. The teacher will do well to introduce here an illustrated account of the mode of origin of leaves from vegetative points. The appearance of nodes and internodes is thus not of primary importance, but is incidental; properly, leaves do not stand at nodes; nodes are places where leaves stand. The student can make out also that the stem must grow through a considerable part of its length, but most actively near its tip, and that leaves grow all through their structure. He should also recognize that the root is a single profusely branching structure, originating from a stem. The ecology of leaf, stem, root, should, of course, be fully explained. This exercise affords also a very good introduction to phyllotaxy. The geotropism of the Coleus shoot may be diagrammed in simple outline figures. The nodules on the roots of Beans, and their part in sup- plying additional nitrogen to the plant, should be explained ; it is a most interesting and important topic, fully treated in the newer books. Most important are the facts shown by Experiment 3. It proves the absorption of oxygen and elimination of carbon dioxide by plants in growth, a process identical with that occur- ring in animals ; and it should be the more clearly emphasized here, since there is a general misunderstanding of the process, 196 THE TEACHING BOTANIST due to a confusion of it with the gas exchange in photosyn- thesis. There is no place in the cycle of the plant's life in which respiration can be studied so free from complication with other processes as in germinating seeds. Experiment No. 3.- -Prepare three U -tubes and three up- right test-tubes, as shown in Fig. 18, or their equivalents. Half fill the test-tubes with, respectively, water, a strong solu- tion of caustic potash, and a concentrated mixture of caustic potash and pyrogallic acid. Place in one arm of each U-tube a half dozen soaked oats, beneath which is a small wad of moist Sphagnum, and cork S~ ~^ -v tightly with rubber stop- pers ; do not allow the arm to become wet above the seeds, or the potash will diffuse over and kill them. Place the uncorked ends of the U -tubes in the test-tubes. The py- rogallic solution will, in a short time, rise in the U-tube about one-fifth of its length, through the absorption of the oxy- FlG. 18. — Apparatus for study of respiration in germinating seeds. The tubes contain, respectively, water, solution of caustic potash, concentrated mixture of caustic potash and pyrogallic acid. X 4. gen ; the seeds will not germinate, or, if at all, extremely little. In the potash tube the liquid will rise to the same height, but more slowly, and the seeds will germinate and grow considera- bly. In the water tube the liquid will scarcely rise at all, though the seeds will grow as in the preceding. Of course, in the sec- ond tube, in the respiration accompanying their growth, the seeds absorb the oxygen and give off carbon dioxide, which is absorbed by the potash, and the latter rises to occupy the THE DIFFERENTIATED PLANT 197 space thus left. Some of the brighter pupils, observing the pyrogallic and the potash tubes alone, would say that all the potash tube proves is that something is absorbed, doubtless oxygen, from the air by the plants, and that nothing is proved to be given off since removal of the oxygen alone necessitates the rise of the liquid. In answer to this is the water tube, the failure of the liquid in which to rise proves that some- thing is given off as well as absorbed, and since the only gas absorbed by potash is carbon dioxide, that gas must be given off in volume equal to the oxygen absorbed. This experiment proves that oxygen is necessary to growth, that carbon dioxide is given off, and that the volumes of gas thus exchanged are equal. This exchange is, of course, respiration, necessary to supply energy for growth. This experiment always works very well with me ; if it fails, it will probably be found that the pyrogallic-potash mixture is not concentrated enough. Practically, it is best to place the pyrogallic acid in the arm of the U-tube, and the potash in the test-tube, when the mixing occurs where it will do most good. There are other very simple experiments to substantiate these results. Thus the giving off of carbon dioxide may be proved by placing in a closed bottle a number of soaked seeds with a small dish of clear lime water, the milkiness of which, after two or three days, will prove the presence of the gas ; while in a similar bottle without the seeds it will remain clear. The students will themselves suggest the identity of this process with respiration in animals ; it is also called respiration in plants. The teacher, by a lecture or otherwise, can make it plain that it is by oxidation of food that both plants and animals obtain the energy needed in the work of growth. Of course, the results of this experiment, with a drawing of the apparatus, should be carefully worked out by the students. 198 THE TEACHING BOTANIST VII. Plasticity of the Shoot and Root in Form and Size 28. In the Bean, Coleus, and Balsam you have studied three fairly typical Mesophytes. The most typical or average form would show a vertical, independent, cylindrical stem, growing by vegeta- tive points at its tip and in the axils of the leaves, and continued into a main root at its lower end. The leaves would stand in definite positions (producing the nodes), separated by spaces (the internodes), and would be arranged either in whorls of two or more at a node, or with but one at a node, and forming a spiral. The leaves would be simple, thin, horizontal, toothed, ovate in form, with a petiole and two stipules. But such a condition is an ideal one and not realized in any single plant, and very wide deviations from it occur in plants as result of adaptation to special habits. In what respects are the plants on the tables modi- fied from the typical or average condition, and what is the probable ecological meaning of the modification ? Your record, of eight plants, should bring out the name of the plant and scale of the draw- ing. It is not necessary always to draw the entire plant, but only its peculiar features. PLASTICITY OF SHOOT AND ROOT 1 99 a. How may simple be distinguished from com- pound leaves ? b. Do leaves always continue to grow straight out from their points of origin ? 29. You have noticed that seedlings turn green as they come into the light, and further observa- tion shows that in general only parts exposed to light are green. It is known to physiologists that starch, which is the real food of plants, is made only in green parts. Is there any connection between these facts, i.e. is light essential to starch formation ? Answer by Experiment 4. The exchange of gases, particularly O and CO2, in these processes, is important. What gas is given off in starch making (photosynthesis or assimilation)? Answer by Experiment 5. If the gas proven by Experiment 5 is given off, inferentially the other is absorbed, and hence necessary to the process. Is it necessary ? Answer by Experiment 6. Materials. - These should be preferably potted plants, studied in a greenhouse or brought to the laboratory ; they need not be injured. Or herbarium material, collected for the purpose on the principle earlier discussed (page 106), may be used. Extreme modifications in adaptation to special function may best be left for another week ; here should come " stemless " plants (primroses, houseleeks), flat-stemmed 20O THE TEACHING BOTANIST (Muehlenbeckia), or extremely elongated (climbers), and others with compound leaves of different kinds, some lacking petioles and stipules, and others showing the leading systems of phyllotaxy well, with some to show how this is disregarded in the final arrangement of the leaf blades. Some showing the leaf function assumed by the stem may be added, including the extreme case in the common " smilax " of the greenhouses. In such work as this, the use of a good scientific greenhouse is particularly advantageous. Valuable plants for this purpose, found in such houses, are Ruscus hypoglossum, Colletia, Utex, Acacia, the latter showing the phyllodes, often with compound lower leaves. Several students may work upon one plant, and they are to be exchanged occasionally. Red labels may be placed upon those to be studied in a greenhouse. Pedagogics. - - This exercise is for training in morphology ; also to give an idea of different modes of venation and com- pounding of leaves, and the main systems of phyllotaxy ; but especially it is to make plain how great may be the changes in size and shape of parts while they retain their original nature, a subject of the utmost importance, and at the very foundation of morphology. The students thus trace out how the leaves alter shape, become compound, have or have not petiole and stipules ; how the stem lengthens or shortens ; how buds multiply or are suppressed, etc., while the relative positions of the parts remain unchanged. Every part may be a centre of variation in form and size. A good conception to place before the students in the summary of their studies is this : to imagine each part indefinitely elastic and compressible, so that any of them may be either greatly drawn out or re- duced, while the relationship of position of stem, leaf, and axillary bud remains unchanged. PLASTICITY OF SHOOT AND ROOT 2OI Care must be taken not to exaggerate the importance of the node. It is not really a distinct structure which inci- dentally produces a leaf, but it is the place where the leaf stands and hence the fibre-vascular bundles of the stem branch and anastamose, giving the " joint " appearance it often, but by no means always, presents. The "phytomer" has really no morphological existence, as I have elsewhere pointed out (page 149), but is only an incidental result of the way the stem is built. Moreover, this exercise should make plain how readily the stem assumes the function of the leaf, and how little distinct these two are from one another. Hence the plant is best described as made up, not of leaf, stem, and root, but of shoot and root, while the former is further differentiated into stem and leaf, and the leaf may be yet further specialized into blade, petiole, stipules. This relation may be expressed as follows : — !stem fBlade Higher Plant I Sho0t I Leaf Petiole I Root c. , I Stipules (see, also, page 149). The main thing now is to teach the fact of the existence of the different kinds of margin, shape, etc., and to show how easily these are derivable one from another, and to give some idea of their meaning. Leaf shape may be treated in a lecture or demonstration somewhat after this manner. The two extremes of shape possible are the circle (accompanying fullest exposure to light) and the line (where crowded), and between them are all variations of ellipses, etc. When an intermediate form is borne out on a long petiole, however, more material is condensed near the petioles, and it gives forms like the ovate, etc. ; when they are crowded together on a short stem so that they would shade 202 THE TEACHING BOTANIST one another, or when without petiole, the material is more condensed toward the tip, giving the obovate, etc. Leaflets may be told from leaves by absence of axillary buds, and by their not originating in whorls nor spirally. There is much value, it is true, in drawing and naming the different shapes of leaves, but it is of much the same nature as the fitting together of some kinds of puzzles ; and the same time and labor may be spent much more profitably upon doing work which is distinctively botanical and scientific. Still, if the teacher values terminology as a discipline, here is the place for it. The teacher should note that the systems of phyllotaxy described in the books and expressed by fractions unques- tionably exist, and may be traced ; and a certain amount of this should be done, enough to give the pupil a clear idea of its principles ; but the teacher should carefully avoid leading the pupils to imagine they find certain fractions which theo- retically ought to be present, for the systems are very easily thrown out by twisting of the stem in growth or by injuries. Of course, the phyllotaxy has very little to do with the ulti- mate position of the blade; it holds true only for the origin of the leaves in the bud. The students will be able to do but little with the ecological explanation of the variations of shape, etc., and here the teacher must give assistance when he can. It is better to call attention to such questions, even if they cannot be solved, than to omit them altogether. In making observations upon the plants, the students should read over with each the account of the typical plant given under 28 ; it is needful for them to have their attention directed to each point, or they will miss important features. Experiment No. 4 is the well-known, valuable, and easy PLASTICITY OF SHOOT AND ROOT 203 experiment described in all books for demonstrating photo- synthesis. Select a living potted plant with large, clear, green leaves ; keep it two nights and a day in darkness (to empty leaves of starch), then bring into bright sunlight, covering one leaf above and below with tinfoil, in the upper fold of which a figure or letter has been cut ; expose this all day to bright light ; at evening drop this leaf into nearly boiling water for five minutes (to kill it and swell starch), then place it in strong alcohol warmed over a water bath, which will take out the green in a few minutes and leave it white, or it may simply be left in alcohol until next day. Then place it in a solution of iodine (made by dissolving a little potassic iodide in water and adding solid iodine until it is of a dark wine color), which turns starch dark blue. The letter or other mark exposed to light will stand out dark blue on a white ground. This may be varied in many ways, as described in different books. Experiment No. 5 is rather difficult to demonstrate well, and the only practicable method is that of collecting in an inverted test-tube over water the bubbles from cut shoots of Anacharis, Cabomba, or some other water plant, which rise and displace the water, as described in all works on physi- ology. The gas must then be tested, which may be done by transferring the test-tube to a very small vessel (slipped under it) and inserting into it caustic potash, when the rise of the liquid will show how much of the gas is carbon dioxide (a very small quantity). If, now, enough pyrogallic acid is added to make with the potash a concentrated solu- tion, the further rise will show how much oxygen (really nearly all of the remainder) is present. This test is difficult to apply, but it is more certain than the usual lighted splinter, or phosphorus, test. 2O4 THE TEACHING BOTANIST Experiment No. 6. — Place two simi- lar plants in bell-jars having ground- glass bottoms, which can be sealed with vaseline to ground-glass plates, as in Fig. 19. In the saucer in one and in the tube in its cork place soda- lime (an absorber of C(X), and in the other place simply sawdust, in order to have all conditions alike in both ex- cept for the absence of CO2, and its presence, respectively. After about two days' exposure to bright light, the application of the iodine test to leaves FIG. 19. - Apparatus for wiR ghow nQ gtarch in those with soda_ study of need of carbon dioxide in photosynthe- lime, and abundance in the other, proving sis- x 5- that CO2 is essential to photosynthesis. VIII. Special Morphology and Ecology of Shoot and Root The plasticity of root and shoot (leaf and stem) in form and structure is far greater than is shown by the examples studied by you under Exercise 28, and even allows of their modification into special new organs for carrying on new functions ; to this end they may be so altered in shape, size, color and texture, as to disguise completely their original nature. Their positions relative to one another in the plant usually remain unchanged, however, and this forms the best guide to the identity of the disguised parts. ECOLOGY OF SHOOT AND ROOT 2O5 30. In the ten plants selected, what is the exact mor- phology and probable ecology of the specialized structures they show ? In each case your record should bring out clearly (in the drawings when possible) : - (a) The evidence which proves their mor- phology. ($) Reasons for your view of their ecology. It will aid in the interpretation of doubtful struc- tures if you will recall the parts or members a typical Mesophyte possesses. The drawings need not include the entire plants, but only the special structures and their connection with other parts. 31. In a sentence explain the idea you attach to the word "morphology"; also to " ecology"; and the exact relationship between them. Materials. — Living plants from a greenhouse are used, or specimens from the structural herbarium (see page 106, invalu- able for this work when living materials are not available) or from the museum, showing highly specialized parts, -- spines, tendrils, pitchers, tubers, etc. A good list of such plants is given in Gray's " Structural Botany," Chapter III. If at the right season, many plants of the native flora are obtainable for this exercise. Much use can well be made here of good figures, such, particularly, as those in Kerner and Oliver's " Natural History of Plants," and in Schimper's " Pflanzengeographie." 206 THE TEACHING BOTANIST Pedagogics. — This is one of the most valuable of all exer- cises. It is one of the very best for training the morphological instinct and also for giving knowledge of ecology. The students should be able in nearly all cases, using relative position as the main guide, to work out with certainty the exact morphological origin of each part, whether from root, stipule, etc. It will be impressed upon them how little the shape, size, color, etc., of organs has to do with their morphology. Of course a complete knowledge of the mor- phology involves an understanding of the exact steps by which the new organ has been formed, i.e. in the case of a pitcher, whether the leaf has infolded and united its edges to form the cup, or (as is actually the case) whether it has grown up as a cup from the start. It will be well for the teacher to have some one or two series of specimens illustrating all the inter- mediate stages of a particular structure, such, for example, as a Barberry spine. In some cases the student will be able to see what the intermediate steps must have been ; but in others this is impossible without a study of embryology, and here (as in the case of pitchers, for instance) it will be necessary for the teacher to supply hints and some information, which students will be prepared to appreciate and utilize after their minds have been once at work upon the problem. It should be made plain to them that the root, leaf, stem, etc., back to which they reduce everything, are not in themselves irre- solvable elements, but simply adaptive structures traceable back to still simpler origins, i.e. back to the thallus. On ecology of the structures they can do little better than guess at uses ; for, removed from their native homes, the plants can give no idea of their habits. Here is where the outdoor study of native plants through field excursions is most valuable. In ordinary temperate climates the ecological adaptations are ECOLOGY OF SHOOT AND ROOT 2O/ so much less marked than in tropical and desert plants, that it will be necessary to use some of the latter in order to give anything like an adequate view of the subject. The teacher must then supply data as to their habits, describing the characters of the desert, the tropical jungles, etc., illustrat- ing by photographs as fully as possible. The teacher must carefully guard against dogmatism in ecology ; at the best this division of the science is at present in a very new and undifferentiated state, and even among specialists much of it is but guesswork. A complete study of this subject involves also an examination of the texture, or tissues ; for adaptation shows itself in minutiae as well as in large features, in the suppression of some tissues and excessive development of others ; but this work is hardly practicable in an elementary course, except very superficially. In this connection the teacher should give fully illustrated lectures or talks upon the very important and interesting subject of the ecological groups of plants, — the Mesophytes, Halophytes, etc. These groups may be classified thus, follow- ing Warming : — A. Groups in adaptation to physical conditions. 1. Mesophytes, Normal Plants. (Trophophytes, those with winter defoliation. Schimper.) 2. Xerophytes, Desert Plants. 3. Halophytes, Strand Plants. 4. Hydrophytes, Water Plants. B. Groups in ndaptation to other organisms. 5. Climbers. 9. Insectivora. 6. Epiphytes. 10. Myrmecophila. 7. Saprophytes. n. Symbionta. 8. Parasites. 2O8 THE TEACHING BOTANIST If materials are available, here is the place for simple physiologic-ecologic experiments upon such topics as the sensitiveness of tendrils to contact, operation of Drosera leaves, etc. IX. The Morphology and Ecology of Winter Buds In climates where a winter stops growth, the living buds must be protected over that time. How is this accomplished ? 32. Study the Horse-chestnut twigs, particularly the buds. Recall your knowledge of how the buds of this tree develop in the spring. (1) What markings does the twig show? What is the meaning of each ? (2) What positions have the buds, and why ? (3) What sizes have the buds, and why ? (4) What shapes have the buds, and why ? (5) What colors have the buds, and why? (6) What is the exact structure of the buds ? (7) What is the morphological nature of each part ? (8) What is the function of each part ? (9) What structures have the buds in com- mon with unprotected summer buds, and what accessory to their protection over winter ? MORPHOLOGY AND ECOLOGY OF WINTER BUDS 209 Your record should express most of these facts in an annotated drawing, the remainder in notes. 33. Study similarly the Tulip-tree twig. 34. Study also the others supplied. Outside of the laboratory, examine as large a series of twigs and buds as possible. 35. Prepare a synoptical essay (not over three hundred words) on the General Morphology and Ecology of the Higher Plant. Materials. — These are abundant everywhere; in place of Horse-chestnut (the best I know) any tree with very large terminal buds will do, especially if containing a flower cluster, as Walnut, Hickory. The bud-scales of the Tulip-tree are modified stipules, hence giving a fine problem in morphology ; Magnolia is the same ; Beech has the same but less plainly. But any large buds of shrubs are good. For comparison, some unprotected buds of greenhouse plants are needed. Pedagogics. — This is one of the most useful and satisfactory of all botanical exercises. The objects are large, fairly definite, and the pupil has data enough to enable him to discover for himself the meaning of nearly every feature of structure and ecology. It is particularly good for training in observation and in morphological reasoning, and in relation of structure to use (ecology). It is most important to recall to the students the general habit and mode of growth of the Horse-chestnut, helping by suggestions when memory fails, and leading one member of the class to aid another, until it has been well worked out Following are features they should work out themselves : — • Under Exercise 32 (i), the lenticels (whose function as 210 THE TEACHING BOTANIST openings for respiration answering to stomata will need to be explained to them, after they have tried to think of a use) ; the leaf scars, with fibro- vascular bundles showing in number answering to the number of the leaflets ; rings of bud-scale scars, with a year's growth between the sets ; and the old scars of fallen flower clusters. Under (2), the buds are terminal and axillary. Under (3), largest buds are toward tip, because the terminal has a flower-cluster, others not, and others are larger toward tip because there is more room there and more light for leaves later ; lower are dormant, and even buried in bark ; ask whether every leaf scar has bud in axil. Under (4), the shape is necessary to hold the many long leaves folded up as compactly as possible. Under (5), brown, because there is no reason for bright color, and the bud scales take the color of composition of cork which happens to be brown. Under (6), dissection of a whole bud is needed, and draw- ings of a bud laid open, and of a vertical section, — or else of individual leaves, scales, etc., and a flower cluster. Under (7), leaf origin of bud scales is shown by their phyllotaxy, their anatomy, and sometimes by transitions to normal leaves ; really they are the petioles, not entire leaves ; in Tulip-tree, they may readily be discovered to be stipules, - a beautiful case of clear morphology which all should be made to work out. The wool is an epidermal outgrowth from leaves. Under (8), the scales form a protecting box ; resin prevents rain from soaking through between them ; the wool does not keep out cold altogether, but it prevents injurious suddenness in changes of temperature. Under (9), the vegetative point with young leaves is in com- mon with the others ; scales and wool are additional. MINUTE ANATOMY OF ROOT AND SHOOT 211 X. The Minute Anatomy of Root and Shoot 36. In the Balsam, after observing the features of the gross anatomy, study carefully the minute anatomy of the shoot and root. I. The epidermal or protective system. (1) Is it continuous and uniform over the entire plant ? (2) Is it removable from the underlying tissues ? (3) Is it smooth or has it appendages ? (4) Do you find stomata or any equivalent for them ? (5) Is there any green in the epidermis ? II. The cortical or starch-making system. (1) Is it continuous over the entire plant? (2) Is it evenly distributed, and, if not, where is the green most intense ? III. The fibro-vascular or conducting and strength- ening system. (1) Is it continuous through the entire plant ? Place a spray in the red liquid to aid in tracing its course. (2) In what order are the bundles arranged in the stem ? (3) How are they arranged in the petioles ? (4) How are they arranged in the leaf? (5) How do they end in the leaf ? 212 THE TEACHING BOTANIST IV. The storage system. All of these systems are to be worked out with simple lens and scalpel. 37. In the young woody stem, what systems may be distinguished ? 38. Construct diagrams showing by colors the dis- tribution of tissues in the plant through shoot and root. Materials. — Balsam (Impatiens sultani} is easy to raise, and very good for this use because of its translucent stem, which renders the fibre-vascular system very distinct, though the distribution of its green tissue in the stem is not as sharply differentiated as usual. Coleus is also very good, and almost any herbaceous plant will do. For Exercise 37 any young woody twigs are good, but those with a greenish bark are best. Pedagogics. — One of the most useful of exercises upon an important phase of anatomy (i.e. the contact of, and transition from, the visible to the invisible) commonly overlooked. It is extremely good for training in minute observation, and also as knowledge, for it gives a good comprehensive idea of the dis- tribution of tissues and of the relation of invisible to visible features likely to be missed in an exclusively microscopic study. Far more of minute anatomy can be traced out with the hand lens than is commonly supposed. It also gives, far better than a microscopic study, an understanding of the general physiological uses of the different tissue systems. For best work on this subject the students should previously in some demonstration or lecture have had their attention called to the general physiological conditions which plants must take account of, — protection against drying up, against animal MINUTE ANATOMY OF ROOT AND SHOOT 213 enemies, exposure of much green tissue to light for starch making, aeration of the interior cells to allow them to breathe, conduction of raw sap to the leaf and of the food substances away, strength to resist winds and other strains, etc. With all these needs and functions fresh in mind, the students should be set to work to find out how they are arranged for in the plant. FIG. 20. — Diagram of distribution of tissues in a typical shoot, upper in longi- tudinal section, lower in cross. Outer line = epidermal system ; radiating lines = cortical system ; crossed lines = storage system ; spiral lines = fibro- vascular system. On these systems see page 219. Important points to be brought out, with their reasons, are : the lenticels on the stem (which are the successors, structurally and physiologically, of the stomata of the younger tissues) ; the greater intensity of the green on the upper, i.e. the best lighted, surface of the leaf; the branching of the bundles at the nodes, and the running of one branch into the leaf and of another up the stem ; the fact that the bundles form a ring in the stem (note the cambium, which, with the vegetative points, 214 THE TEACHING BOTANIST forms a growth system) and that one, two, or three run out through the petiole and branch profusely, ending either as very small veinlets anastomosing, or else each ending abruptly in a small green area (shows well in Asarum) ; the tapering of the veins regularly and for mechanical reasons. With eosin or safranin prepare tumblers filled with red dye and place cut shoots in them ; in a few minutes the fibro-vascular system will be completely stained. Slides and covers should be given to allow students to mount all sections in water. Excellent thin sections can be made with their scalpels, which they may sharpen on the laboratory whetstone provided for the purpose. A diagram like that called for in Exercise 38 is shown in Fig. 20, where the colors are represented by special shading. XI. The Cellular Anatomy of the Shoot — the Leaf in Particular In studying cellular anatomy, one is dealing directly with cells. 39. What is the structure of a typical plant cell ? Answer by a study of the living cell in the stamen-hair of Tradescantia. For this the compound microscope is needed, the use of which will be explained to you. 40. What is the cellular structure of the protective system of a typical leaf ? Answer by a study of the epidermis of Trades- cantia, which may be peeled off after a study of it in position. Notice particularly the guard cells and stomata. CELLULAR ANATOMY OF THE LEAF 215 41. What is the cellular structure of a typical leaf? (1) What is the structure of the starch- making system ? (2) Of the conducting and strengthening system ? (3) Of the aeration system? (4) Of the protective system ? Answer by a study of the Rubber-plant (Ficus elastica) leaf. Observe carefully the characters of the leaf as a whole ; then cut thin cross- sections with your scalpels and compare with the prepared sections. All of the systems should be represented in a single drawing. 42. It is a well-known fact that leaves give off into the air considerable quantities of water. It is desirable to measure exactly how great the quantity is for an ordinary plant under normal conditions, and also how the rate of this giv- ing-off, or transpiration, is affected by changes in the external conditions. To determine it, the most exact method is weighing, and to employ this, it is necessary to use a potted plant in which all evaporation is prevented, except that through the leaves and stem. This has been done in Experiment 7. (i) What amount of water may be given off by a plant under normal conditions, 2l6 THE TEACHING BOTANIST and how is the rate affected by dif- ferent external influences ? Answer by Experiment 7. (2) What structures in the leaf are con- cerned in this process of transpira- tion ? •;3) What is the use of transpiration to the plant ? Materials. — For study of living plant cells, the best object known to me is the stamen-hair of Tradescantia virginica, which is easily obtained in gardens in late spring and summer, but not at other times, unless the plants are cut back in the spring, when they may be made to flower in the late fall ; and if covered at night by a frame and sash, they may be kept in good condition until near December ist. T. pilosa, common in greenhouses, gives hairs less excellent but serviceable. The hairs should be placed in water on a slide under a cover glass. Another classic object for the purpose is Nitella (or Chara), which may be found in streams in summer and kept in aquaria all winter, but they are far less typical than Tradescantia. The latter is particularly valuable because it shows not only a typical cell of the higher plants reduced to about the lowest terms, i.e. nucleus, cytoplasm, vacuoles, and wall, but also shows the cytoplasm in active circulatory movement. Its simple structure makes it very good to begin with, for in studying other cells later the student has little or nothing to unlearn, since others are mostly like it with but additional parts. Good living plant cells may be obtained also from many epi- dermal hairs. Of course, knowledge of the cell should be broadened by observation of mounted as well as other living CELLULAR ANATOMY OF THE LEAF 2 1/ cells, and by the study of good figures from books. For epidermis the best object is the Tradescantia pilosa or Wan- dering Jew, common in greenhouses, particularly the leaves with a purple color on the under side. By holding these up to the light the stomata (guard cells) may be seen with a lens, showing green against the purple, and the epi- dermis easily strips off; it should be placed in water under a cover glass. For the entire internal anatomy, leaves of India Rubber Plant (Ficus elastica} are very good, and are easy to section fairly well with scalpels ; they should be cut across the bundles which run out from the midrib. But prepared and mounted microtome sections are necessary for the full demonstration of cellular anatomy. Such sections show the tissues in great completeness and beauty. The Ficus leaf cannot well be used for the epidermis and stomata, for in it these are far from typical. Pedagogics. — This exercise is to teach the structure of the plant cell, the use of the microscope, and the nature of the cellular anatomy of the higher plants, and also is for training in observation of minute but definite objects. The subject is difficult for beginners, but is altogether too important to be omitted from a well-proportioned course. In teaching the use of the microscope, its proper function as simply an aid to vision, and not as a tool with mysterious properties of its own, should be made plain from the start. This is best done by leading students to see all possible with the naked eye ; — when the limit of this is reached, then simple lenses are to be used, - - and when limit of these is reached then low powers of the microscope ; certainly all possible of cellular anatomy should first be brought out without the micro- scope, and they should not take to its use until it is unavoid- able. To learn how to focus, move objects, etc., the low power 2l8 THE TEACHING BOTANIST and bits of printed paper on slides are good. Every needful operation of placing the stamen-hairs on the slides, peeling epidermis, etc., should be done by the students ; and when sections must be cut for them on the microtome, they should have sections of their own also before them, so they may know just what the former represent. Naturally, along with Exercise 39 a great deal of description of function, etc., must be given, and from the start the fact that the cell is essentially the protoplasm, and the wall but a passive skeleton or box, should be made plain, as also that the movement in Tradescantia is unusually rapid. Parts they can see are, - - the circulating cytoplasm, full of food granules, the nucleus, particularly important in reproduction, the vacuoles, filled with cell sap, forming a reservoir of water and dissolved food substances, and the containing wall. Under Exercise 40, the precise relation of guard cells to sur- rounding cells is important as a point of observation ; also that nuclei can be seen in epidermal cells, also that guard cells contain chlorophyll. This is particularly good as an exercise in observation. Students must be led to interpret the tissues in terms of cells ; i.e. protoplasmic masses with walls, from which, later, protoplasm may be withdrawn. Under Exercise 41, the drawings should show relation of structures as magnified to those not ; i.e. it is better to have students learn to represent just what place their most highly magnified section has in the leaf, as shown on a piece of the leaf unmagnified. Very important is the tracing of the aeration (intercellular) system, its continuity through the leaf, and its connection with the stomata. The palisade layers should be represented as cells - - not as a shaded green layer. All of the tissues should be studied from the point of view of function, as a basis for which their knowledge of the conditions of CELLULAR ANATOMY OF THE LEAF 2IQ weather, strain, light, physiological work of the leaf, should be recalled to them and further illustrated and explained. The tissues should be studied as protective system, starch- making, strengthening, conducting, aeration, etc., to which the names epidermis, parenchyma, sclerenchyma, ducts, sieve tubes, and intercellular spaces may later be added. In the drawings the cells must be represented as complete structures individually, not simply by uniform shading. Students should be led to view the leaf, not as a mass of cells put together, but as a mass of living substance separated into cells, flattened to expose chlorophyll to light, and needing protection against drying up, a strengthening framework, two sets of conducting tubes, exposure of all living cells to oxygen for respiration, etc. Important, too, is the mode of combination of tissues, — how they are arranged to interfere as little as possible with one another's function. Something of the excretion system may be made out in the fine large crystal cells (cystoliths) in this leaf. This work will require at least ten hours from the average student, and should have more. It is worth it. Naturally, they should be shown other leaves, and especially the mode of ending of the fibro-vascular bundles in the areas of green tissue, which is perfectly plain to the naked eye in Asarum leaves, and with a lens in Cabbage. Also forms of trichomes, hairs, etc., which belong with the protective system, should be shown. These should be in the structural herbarium. The systems of tissues may well be treated as follows : — Protective — epidermis, cork. Starch-making — cortex. Strengthening — sclerenchyma. Growth — cambium and vegetative points. 220 THE TEACHING BOTANIST f raw materials - - ducts. Conducting : \ ( food materials — sieve tubes. Aeration - - intercellular passages and stomata. Excretion - - special crystal cells. Storage- -pith, medullary rays (and cortex in roots). Experiment No. 7.- -Prepare a plant as shown in Fig. 21, i.e. place it in a glass jar and cover with dentist's thin sheet rubber, tightly tied both to jar and to plant, but pierced by a thistle tube which is closed by a piece of the rub- ber (or cork) that can be removed. All water must then come out through the leaves and stem. Place the plant on the scale pan of a good balance (the Harvard trip-scale, used in elementary courses in phys- ics, is good), and weigh it at intervals. Add water through the tube, carefully weighing the plant before and after, to find the amount added ; it is very essential to the health of the plant not to add too FlG. 21. — Method of preparing a plant for i -, ,, . , much, and this can be transpiration experiments by weighing. XJ. judged either by the amount given off, or by the appearance of the earth in the pot, which should be allowed to become nearly dry between CELLULAR ANATOMY OF THE STEM 221 each watering. By placing the plant under different con- ditions of light, heat, etc., the effect of those conditions upon transpiration may be determined. The larger the plant, i.e. the more leaf surface, the better, since the weighings may then be relatively more accurate. Instead of the glass jar the plant may simply be wrapped in rubber, but as this does not permit the earth to be seen, there is danger of giving too much or too little water, to the great detriment of the results of the experiment. There are many other ways described in various books, of measuring the amount of water removed in transpira- tion, but none are so satisfactory as weighing. Transpiration is of great importance, both physiologically and ecologically, and should be discussed fully by the teacher. As in other experiments, as much of the work as possible should be done by the students. The fact that it, like photosynthesis, has no equivalent in the animal economy, should be emphasized. Probably its chief use to the plant is to enable it to lift mineral matters from the soil into the leaves where they are needed. XII. The Cellular Anatomy of the Shoot - the Stem in Particular 43. What is the cellular structure, and what tissue systems are represented in typical stems of the higher plants ? Since stems fall, as to their structure, into two distinct types, it is neces- sary to select representatives of each. What is the cellular anatomy of the Corn stem ? What is the distribution of its tissue systems ? 222 THE TEACHING BOTANIST Your record should show the exact relation be- tween the gross and the cellular anatomy. 44. What is the cellular anatomy of the Aristolochia stem ? Answer as in the preceding. 45. Construct two diagrams showing by colors the homologies of the tissues in the two stems. 46. With the Aristolochia stem compare a piece of Oak wood. What are the homologous parts ? 47. The phenomena accompanying growth in size, and how it is affected by external conditions, are best manifest in stems. To study it properly we must provide some method of measuring its amount, and preferably some method that will be self-recording. This is accomplished by the auxanometer used in Experiment 8. Under ordinary conditions, at what time in the twenty-four hours does an ordinary plant grow most in length ? Answer by Experiment 8. In what way does temperature affect rate of growth ? Materials. — Indian Corn stems under i cm. diameter, put in formaline in summer, are needed. Aristolochia sipho, the " Dutchman's Pipe," grows over porches in most towns, and is the classic stem for the purpose, showing with the greatest clearness, in comparison with the Corn, the relation between the exogenous and endogenous composition of the stem. CELLULAR ANATOMY OF THE STEM 223 Pedagogics. - - Much as in the preceding. For both stems it is best to use prepared and mounted sections, which show with perfect clearness the cellular character of all the systems. These should be given students, of course, only after they have made out all possible with their own rougher hand-made ones. Most of the work must be done with cross-sections, as the longitudinal can be made to show very little unless cut ex- tremely thin ; but students, after some instruction, soon learn to recognize the tissues from a single view. In Corn, as matter of observation, the companion cells at angles of the sieve tubes should not be missed. In Aristolochia, the sclerenchyma ring, continuous when young, and broken by expansion of stem later (when the stem twines and needs it no longer for support), should be noted. This is a particularly easy stem for tracing the development of the systems of tissues, which may be done by sections at intervals along the stem. From the Aristolochia, through young Oak twigs, the transition may be followed from the distinct bundles of young stems to the woody mass of older stems, in which the separate bundles are lost. Note homologies of the parts of the young twigs and old wood, particularly in the annual rings and the medullary rays, which latter in the Oak form the shining plates sought for in " quartered "' Oak. In Aristolochia, note morphology of pith, and of medullary rays as simply in origin the paren- chyma between the bundles. Also note usual identity of starch-making system and cortex. Trace here homology with the leaf, and how the green parenchyma of the leaf answers to cortex. Note how, in the older stem, epidermis is replaced by cork layers. Exercise 45 is most valuable ; it will impress the real rela- tion of the two types of stems ; there will be a difficulty with 224 THE TEACHING BOTANIST the cortex and pith in Corn, which are not separable, and colors must merge one into the other. Most important is the practice of recognizing the different tissues with naked eye or hand lens ; much histology without a microscope, is possible, and important in many features of adaptation. It will be profitable to examine cross-sections of other young twigs and different kinds of wood. Experiment No. 8.- -For this, some form of auxanometer or growth-measurer, is needed, of which there is a great variety of forms. Only a self-recording form is really useful, and those on the market are very expen- sive. A fairly satisfactory form can, however, be made as fol- lows, at a cost of about $2 (see Fig. 22). Buy a dollar clock, four inches in diameter, and remove hands, face, and surplus wheels until only the steel spindle, three- quarters of an inch long, stands up above the works. Have turned on a lathe a cylinder of hard wood one foot long and an inch in diameter, in one end of which a hole somewhat more slender than the spindle of the clock is turned, truly centred. The cyl- inder may now be forced gently down on the spindle, on which it will revolve evenly once an hour. Have turned also from good maple a double wheel like that shown in the figure ; the outer wheel is grooved, FlG. 22. — A recording auxa- nometer. X . CELLULAR ANATOMY OF THE STEM 225 and through the common axis of both a fine, smooth hole is turned by which the wheel will revolve with very little friction on a clean new needle fixed horizontally by solder or sealing-wax to a firm horizontal support. From the very tip of the stem to be studied a fine silk thread, thoroughly waxed to prevent absorption of moisture, is to be run several times around the small wheel to which its end is fastened by a small drop of glue. A similar thread is to be run around the large wheel and fastened, while the free end carries a pen pressing against a paper on the cylinder. This paper should be smooth, put on the cylinder while mois- tened, and gummed by the free edge, so that when dry it will fit without wrinkles. The pen is to be made from a small piece of slender glass tubing bent into a curve so that both ends, carefully smoothed, rest against the paper ; but one of them is drawn into a capillary point and bent and filed so it rests at right angles to the paper. A chronograph ink should be placed in this pen, on which weight enough should be placed to make the wheel turn as the plant grows. As the plant grows the pen will descend, marking a spiral line on the paper, and the distance apart of the spirals where they cross any given vertical line will give the exact amount of growth per hour, magnified, of course, just in proportion to the rela- tive sizes of the wheels. Half-hour periods may be found by ruling two vertical lines at 180° apart, and then removing the paper on one side between them, bringing the vertical lines together. Of course, the paper with the record may be re- moved from the cylinder for preservation. Rapidly growing flower stalks of such plants as Hyacinth are very good for this purpose, but any parts that are growing vertically may be used. Variations in temperature can easily be effected where there is a Wardian case ; or even by leav- Q 226 THE TEACHING BOTANIST » ing windows open at night, etc. In case there is not room under the wheels for both clock and plant, the latter must be placed to one side, and the thread run over some smooth support, such as a clean screw-eye, as shown in the figure. Another physiological topic of much importance that may well be taken up here is that of the autonomous movements, particularly circumnutation, of stems. This subject is easy of experiment, and particularly good directions are given by Darwin and Acton in their " Practical Physiology." The glass plate on which records are to be taken may be placed at any desired height by supporting it upon three legs in which grooves to hold the plate are sawn at different heights ; the legs are held to the plate by a wire bound around them all. Particularly instructive in this study are the hypocotyls of seeds just bursting from the ground. The well-nigh universal occurrence of circumnutation movements is a point of con- siderable value as knowledge. XIII. The Cellular Anatomy of the Root 48. What " is the cellular anatomy of a typical root ? Answer from a study of the specimen supplied. 49. What is the external structure of the young roots of the Radish ? In particular, what is the structure, distribution, and mode of connection of the root hairs with the root ? How much of the internal structure of the tip can you see with your lenses ? (Something more will be shown if you soak the tip for a few CELLULAR ANATOMY OF THE ROOT 22/ minutes in strong potash, then remove and wash it and mount it on a slide in water.) 50. From observation of the appearance of the young roots with their remarkable development of hairs, it would seem probable that these form the struc- ture for absorbing liquids into the plant, and experiments have proven that this is the case. Since, however, observation proves that the hairs and the root tips have no openings, but form a closed system, it is plain that the water must be absorbed through imperforate membranes. The question then arises, Is there any physical pro- cess by which liquids can be absorbed through imperforate membranes ? This may be answered from Experiment 9, where a membrane (a sort of gigantic hair) has water outside and a solu- tion of sugar inside, precisely as the root hair has. In this experiment, the membrane and an absorbing plant stand side by side. Can liquids be absorbed through imperforate mem- branes ? Answer from Experiment 9. It is also important to know whether the absorp- tion is merely a passive rilling of open tubes or an active process that can overcome resistance. This may be learned by attaching a pressure gauge in place of an open tube, as has been done in Experiment 10. 228 THE TEACHING BOTANIST Can pressure be exerted in this process of absorp- tion ? Answer by Experiment 10. 51. Prepare a synoptical essay (of not over three hun- dred words) on the Cellular Anatomy of the Higher Plant. Materials. - - Roots are much alike in their anatomy, and almost any will do for the anatomy of the shaft called for in Exercise 48 ; the students' own scalpel sections will show rela- tive development of the principal tissues. Splendid tips and root hairs may be obtained thus : take a small, very porous flower-pot saucer and place in it seeds of Radishes or Mustards, soaked a few hours ; cover with another saucer and set it in a dish of water deep enough to keep the seed saucer always wet. In three days the roots and hairs will be perfectly developed. As many saucers and as few students as possible to each is best. It is also well to have a few of the same kinds of seeds sown at the same time in earth, to show how the earth affects the growth of the hairs in com- parison with their free and symmetrical development in the saucer. The hairs in the saucers wilt very quickly when exposed to the air. The Mustard shows the tip and cap, with the radiating lines of growth, even without any special treatment and with a simple lens, but the potash makes them much plainer. Pedagogics. - - An exercise excellent for observation, and particularly valuable for its introduction to the very important subject of absorption of liquids. Under Exercise 49 they should not fail to make out that the zone of hairs advances not bodily, but by growing in front and dying behind. Here CELLULAR ANATOMY OF THE ROOT 229 also it is profitable to try a simple demonstration experi- ment proving that the growth of the root is entirely at the tip, which can be done by taking a large root of a ger- minating Bean and marking it with waterproof India ink at short regular intervals ; it is then allowed to grow on farther in a thistle tube, as described in works on physi- ology. The marks may be put on with a stretched thread dipped in the ink ; such marks will not run as do those made with a pen or brush. It is particularly important that students observe that the roots contain no openings, but are a closed system. The distinctness of the growing point, and the protective cap, should be noted. The explanation of osmosis, the physical process by which the liquids are absorbed in both cases in Experiment 9, is not easy for beginners, nor are botanists and physicists agreed upon the precise nature of the process. It will probably have to be sufficient with beginners to point out to them the physical fact, illustrated fully by Experiment 9, that when a certain solution is on one side of a membrane wettable by water, and water on the other, the water will pass in, while if the membrane is wettable by the solution, some of it will pass out, though not so much as enters ; but if the mem- brane is not wettable by the solution, none of the solution will pass out. For the teacher's own satisfaction, however, the subject should be well worked out, whether he gives it to his students or not. The membranes have no holes that the most powerful microscope can discover, yet there must be openings of some kind, as otherwise the water could not pass. These are supposed to be spaces between the ulti- mate particles, called " micellae," of which the membrane is believed to be composed. There are two possible views as to the nature of the osmosis, — one, that water is strongly 230 THE TEACHING BOTANIST absorbed by the membrane in virtue of an adhesive attrac- tion between them, but is robbed from the membrane by a stronger adhesion between the dissolved substance and the water, and the limit of the pressure that can be exerted in osmosis would be the limit of this adhesion. The more generally accepted, and probably more nearly correct, view is based upon the fact that the osmotic pressure that can be exerted by any solution is exactly that which the dis- solved substance would exert if converted into a gas confined in the same space at the same temperature. Hence the substance is supposed to be in a compressed gas-like con- dition, constantly exerting expansive pressure, but limited by the boundaries of the liquid in which it is dissolved. Thus the latter is tending always to expand, and hence it will easily absorb any liquid offered to it, as from a wet mem- brane, and this allows it to expand, and hence to rise in a tube, etc. Therefore, when there is a continuous supply of water, as in our osmometer, there will be a steady rise of the solu- tion until the limit of the gaseous expansion of the dissolved substance has been reached ; and hence, also, if this liquid be confined (as in the Pfeffer's artificial cell, particularly well described in Goodale's " Physiology," which the teacher should carefully study in this connection), it will exert pressure upon a gauge. Of course, the energy enabling the gas or dissolved substance to exert its pressure is derived from heat in the atmosphere. The marked difference between the osmometer made by the diffusion shell and the root hair, in that the former allows some of the sugar to pass out, while the latter does not, must be emphasized. In the root hair there is not only a membrane comparable with the parchment, viz. the cellulose wall, but an additional one, a lining film of pro- toplasm, which in the root hairs (but not always in other CELLULAR ANATOMY OF THE ROOT 231 living cells) is impervious to the sugar solution. Another difference between them is that the membrane opens into an open tube, while the root hairs do not, but communicate through lines of living cells with the ducts in the root and stem. How the water gets from the hairs unto these ducts is as yet entirely unknown. But the primary physical process is the same in the parchment cup and the living root-hair cell, and in Experiment 9 one may say that on the one side we have a great number of tiny hairs, and on the other a single gigantic one. Experiment No. 9. — Take two burettes of 16 mm. diameter, and remove the bottom up to 2 cm. below the beginning of the gradu- ation, and smooth the cut end in the flame. Over one of them fit a soaked diffusion shell of 16 mm. diameter (which may be obtained of Eimer and Amend of New York), and tie it to the burette very tightly with a waxed thread. Fill it with a thin solution of molasses up to the zero mark. Such an instrument is a very effi- cient osmometer. The molasses may be made stronger if quicker working is desired. These shells are the best arrangements for the FIG. 23. -Osmometers constructed purpose I know of, but if they are from a parchment shell and • ill • r j from a living plant, xl. not available, a piece of good parchment (generally obtainable of bookbinders) may be soaked and stretched tightly over the lower end of the burette ; of 232 THE TEACHING BOTANIST r course, with its smaller surface, it works far more slowly than the diffusion shell. To the other burette a plant is to be attached as shown in Fig. 23. Select an actively growing plant with a stem about the size of the inner diameter of the burette. Cut it off an inch from the earth, and attach it to the burette by a rubber tube fitting over both it and the plant, and tie it tightly to the plant with a rubber band so there can be no leak. When plant and osmometer are placed side by side, as in Fig. 23, the demonstration is very in- structive. A film of oil may be placed on the liquid in both tubes to prevent loss of any of it by evaporation. Of course, very careful records of the rise should be made by the students. Exact measurement has great pedagogic value in itself, and a habit of preferring precise quantitative results to loose generalizations should always be culti- vated. Experiment No. 10. - - A simple and effec- tive pressure gauge may be made as follows (Fig. 24) : Take a glass tube with a glass stop-cock at 'one end, and graduate it in millimetres and centimetres with India ink applied with a stretched thread. Select a vigorous plant with a stem about the diam- eter of the inside of the tube, and cut it off an inch from the ground. On the top FIG. 24. — Gauge for of the stump fit a short piece of rubber measuring root pres- tubing thick enough to make stump and outside of tube the same diameter, and slip another piece of tubing over this and the tube so as to make a water-tight joint. This joint must next be made ANATOMY AND MORPHOLOGY OF THE FLOWER 233 inexpansible to pressure from within, which can be done by winding it tightly and carefully by several turns of tire- tape (used for repairing bicycle tires). Enough water should then be put into the tube to bring it up to the zero mark, and the stop-cock (a perfectly air-tight one) should then be closed. The water forced out from the stump will then compress the air column, and the exact pressure exerted may be calculated by Mariotte's law, — that pressure is inversely proportional to the volume of the gas. Thus, suppose the air column is compressed to three-fourths of its former length ; this means a pressure upon it of four-thirds. But it had one atmosphere, that is, three-thirds, upon it at the start ; hence the additional pressure exerted by the water will be one-third of an atmosphere, or about five pounds to the square inch. This implies that the readings shall be taken always at the same temperature, which is not difficult to manage, and it neglects a slight error due to the water vapor in the tube, but the latter is at the most very small. The ingenious teacher can make a tube without the stop-cock, perhaps even a closed test-tube, do. The plant is, of course, to be watered regularly, but not too much, or the roots will soon die of suffocation. Another very instructive experiment upon roots is one to show their hydrotropism, a most important irritable property ; methods of demonstrating it are given in all physiological works. XIV. The Anatomy and Morphology of the Flower 52. What is the structure of the essential parts of the flower - - pollen-grain and ovule ? Answer from a study of the material supplied, 234 THE TEACHING BOTANIST The microscope must be used. After examining the pollen dry, add water, and observe the effect. After examining the ovules, placed on a slide in water, as fully as possible, add potash, which may make their structure clearer. 53. What is the exact structure of the Scilla flower ? (1) Of what distinct parts is it made up ? (2) In what relative positions are these arranged ? In addition to your drawings, construct diagrams which shall show in ideal horizontal section the ground plan of the flower, and in ideal vertical section, the vertical plan. In each case repre- sent sections through the most typical parts of the structures. The two diagrams are comple- mentary to each other, and one need not repeat what the other shows. 54. In your earlier studies you have found that the flower originates as a branch does, i.e. from an axillary bud. In what way does the Scilla flower answer to a branch, i.e. in what way have stem and leaves altered their shapes and positions to form the parts of the flower ? Represent by diagrams the intermediate stages between leaves and the parts of the flower. 55. What is the function of each part of the flower? 56. After the same manner study the Hyacinth flower. Represent by diagrams only. ANATOMY AND MORPHOLOGY OF THE FLOWER 235 Materials. — For pollen and ovules, those of Scilla or Hya- cinth are good. For the structure of the flower, if this work comes in summer, Trillium or Buttercup are both very good. If in winter, Scilla siberica, squill, is the simplest and most typical plant available ; it is extremely easy to raise in shallow boxes ; the bulbs, each supplying several flowers, are cheap, and any skilful gardener can have them ready on a given date. Tulips are good, but expensive. Next best is Hyacinth, the single white Roman kind, but this is much less simple and typical. These are grown for sale in most greenhouses, and flower so abundantly they are not expensive. But of course others will answer, though kinds with superior ovary must be selected. In summer many simple forms may be collected and preserved in formaline, or even dried and pressed, but in the latter case they must be soaked out in warm water, and are far inferior to fresh flowers. It would be a mistake to give a pressed flower to a pupil to begin with. Pedagogics. — A study in observation, recording, and knowl- edge of the flower. The introduction to the flower through the study of pollen and ovule is extremely important as helping to impress upon students what is really essential to it. An account of fertilization and its meaning should here be given. Under Exercise 53 the study is purely in anatomy. At this stage of their work they should be able without special help to work out fully and correctly the structure of such a flower as the Scilla, and to represent it well. They should not miss such points as that three of the perianth parts are outside of the other three, that there are three cells to the ovary, that the ovules are on a central placenta, and that the anthers contain pollen. But too much detail, such as kinds of ovules, dehiscence of anthers, etc., must not be expected at this stage, else time is lost and proportion is destroyed ; the 236 THE TEACHING BOTANIST most essential things first, is the best rule. Terms for the principal parts - - perianth, petals, sepals, etc. — and for the conditions of union of parts, -- gamopetalous, gamophyllous (for parts of a perianth), etc. - -should be given after the need for them has been felt. The construction of the diagrams is the most important pedagogical part of this exercise. They will be spoken of below. In the morphology, the students should of themselves recog- nize that receptacle is stem which remains short, that petals and sepals are leaves ; but stamen and pistil, particularly anthers and ovules, will puzzle them. They should be allowed, or, if necessary, led to see that the latter are not homologous with anything they have yet studied ; in fact, so far from representing modified edges of leaves, etc., they are as distinct from leaf or stem as these are from root, and they are older than the leaf or the stem (see page 146). They are sporangia containing spores, an inheritance from the non- flowering plants, with certain appendages added. The ovule (nucellus) is a spore-case containing a single spore (macro- spore or embryo sac) whose germination produces the egg- cell, the whole surrounded by one or two protective coats. The anther is a spore-case containing spores (microspores or pollen-grains) whose germination produces ultimately the pollen tube with its contents. The pistil is composed of in- folded leaves with the spore-cases on their edges. It is a mis- take to try to homologize the ovary, style, and filament, with blade or petiole of a leaf, for the differentiation into blade and petiole is an attribute of the foliage leaf only, not of the spore- bearing leaves, which, it is possible, have not been derived at all from foliage leaves (see page 147). I have found it in my own experience most profitable to teach the correct mor- ANATOMY AND MORPHOLOGY OF THE FLOWER 237 phology of these parts, including ovule and pollen-grain, from the start; pupils understand it as readily as they do the formal and partly incorrect morphology current in many of our text-books, and they have nothing to unlearn later. It is usually assumed that a perianth tube, such as the Hyacinth has, is composed of united petals and sepals; this is not strictly true, for the tube is probably not made by the union of the bases of petals and sepals, but by a ring of tissue under the bases of the petals and sepals, which is one con- tinuous structure, a sort of ring leaf, and not six united parts (see page 148). The point is very important for an under- standing of the composition of complex flowers. The function of pollen and ovule can best be given them through an account, fully illustrated by diagrams, of the process of fertilization. That of calyx can be illustrated by reference to buds where it is a protection to the young parts. As to the showy corolla, its use can be brought out by such a line of reasoning as this : Experiments and observation have shown that better seed is produced when pollen and ovule come from different plants; this requires the locomotion of pollen from one plant to another ; this is often brought about by wind, but that is a very wasteful method ; a much more economical mode of locomotion of the pollen would consist in using some agency which could be made to move from one flower to an- other ; small animals, particularly insects, form such an agency, but some inducement must be provided to make them visit the flowers ; this is generally done by nectar, on which they feed ; but the place where the nectar is must be shown them so they may find it ; this is done either by strong odors, or else by color ; the special structure developed to hold the color is the corolla. Later the argument may be continued thus : not only must the insect be brought to the vicinity of the nectar, and 238 THE TEACHING BOTANIST therefore of the pollen, but it must be made to approach the nectar in such a way as to leave upon the stigma the pollen it has brought, and to take a new supply ; hence the different shapes and sizes of flowers — shape being chiefly to make the insect enter the flower in a position proper to secure the pollination, and size being in general related to the size and form of the visiting insect. This mode of reasoning must be used with great caution, and not allowed by the pupils without the most complete evidence for their arguments. It is im- possible, however, for them to work out without great time and labor the true theory of the flower, and a theoretical account of it like this is much better than none. It would be far better to obtain a basis for such a description by study of wild flowers out of doors in summer. Like most other teachers, I have used blank forms for description of flowers, but have abandoned them, not because they are not valuable if properly used, but because much more good can be obtained from the same amount of time and labor spent as here recommended. Besides, the blanks imply a great amount of work on terminology, which again, while far from valueless, does not, nevertheless, in my opinion, con- stitute the best use that can be made of the students' energy and time. Of great value in the study of flowers is the representation of the fundamental facts of their structure by horizontal and vertical diagrams as called for under Exercise 53. These are intended to represent, not superficial features of form, etc., so much as fundamental relations of number, relative position, coalescence, etc. Ground plans for this purpose are given in all works upon floral structures, but the equally useful ver- tical plan is much less used. As an example, there are here given these diagrams for Scilla and Hyacinth (Figs. 25, 26). ANATOMY AND MORPHOLOGY OF THE FLOWER 239 The following principles should be observed in their con- struction. The two kinds are complementary to one another, and it is not necessary to try to show in one what is already brought out in the other. Relations of number, alternation and coalescence of like parts, are brought out in the horizontal, and general form and adnation of unlike parts in the vertical. Conventional signs, as shown by the accompanying examples, can be used for the parts. Form should be shown only so far as possible without interfering with the clearness of repre- FlG. 25. — Diagrams of Scilla flower. Receptacle dotted; carpels cross- lined ; petals black ; sepals and stamens unshaded. sentation of the more essential features. They should be constructed with the most rigid exactness, every spot and line having its meaning, and no confusion of lines allowed. Particularly important is the insertion of parts upon the re- ceptacle and upon one another ; and lines should not be allowed to touch one another in the diagram except in order to represent parts grown together in the flower. The help of compasses, etc., should be required, if necessary, to make them symmetrical. Teachers should remember, how- 240 THE TEACHING BOTANIST ever, that while these diagrams are extremely useful servants they are bad masters. In my own experience I have found FlG. 26. — Diagram of Hyacinth flower. The vertical lines show the perianth tube ; other shading as in Fig. 25. nothing to equal them for compelling clear ideas on the part of the student. XV. The Morphology and Ecology of the Flower 57. What is the exact structure and morphological composition of the Snowdrop flower ? Express in the horizontal and vertical diagrams. MORPHOLOGY AND ECOLOGY OF THE FLOWER 241 By special shading bring out the exact morpho- logical nature of each part. What adaptations to cross-pollination does it show ? 58. What is the exact structure and morphological composition of the Narcissus flower ? Answer as for the above. 59. What is the exact morphological composition of the Primrose flower ? Answer as for the above. 60. Tabulate the resemblances and the differences between the Scilla and the Primrose. 61. What is the exact morphological composition of the Fuchsia flower ? 62. What is the morphological composition of the Eupatorium flower ? 63. What is the morphological composition of the Cytisus flower ? In the diagrams the irregularity may in a gen- eral way be represented; but it must not be allowed to interfere with the clearness of the ground plan. Materials. — The Snowdrop is the very best of flowers with inferior ovary, and worth much trouble to obtain. Fuchsia is also extremely good for a flower with inferior ovary, and easy to obtain at florists. Narcissus and Freesia are also good. Prim- roses, grown in large numbers for sale by all greenhouses, are very good and not expensive. The range of materials used in the preceding exercise and in this is ample to explain fully the 242 THE TEACHING BOTANIST morphology of the flower. For a Composite, which can readily be understood at this stage, the small white Eupatorium often grown in greenhouses is very good, but others will do, such as Cineraria, or Senecio petasites. If irregular flowers are added, any papilionaceous flower will do, of which some kinds are always in greenhouses. Pedagogics. - - More specialized flowers are here taken up, and some that are irregular. The question of the morpho- logical composition of the wall of the inferior ovary must be faced. Students may best be introduced to this by stating to them the fact, illustrated by diagrams, that every flower, no matter how specialized, originates as a set of originally distinct leaves on a conical receptacle ; let them reason from this in the case of the Snowdrop, and if they are not previously prejudiced by the calyx-adnate-to-the-ovary theory, they will readily see that the stamens, petals, and sepals must stand on the receptacle, which therefore must form the wall of the ovary by growing up in the form of a hollow cup, while the carpels form the roof over it, and also the partitions. This is the morphology which embryology sustains. In the Fuchsia the morphology of the ovary is the same, but here, in addition, a tube is formed after the manner already spoken of for the Hyacinth and Primrose In the Composite flower the mor- phology is very like that of Primrose and Fuchsia, i.e. the ovary is a hollowed-out receptacle on the top of which the sepals, often finely divided into a pappus, and the corolla-tube stand. In diagramming the flowers of the Snowdrop, etc., it is well to use shading of the different parts, to represent their exact morphology. In the preceding diagrams (Figs. 25-26) this is done, and in the same way it may be done in the Fuchsia (Fig. 27). In diagramming the irregular flowers, as the Cytisus, a part of the irregularity can be shown, but it must MORPHOLOGY AND ECOLOGY OF THE FLOWER 243 never be allowed to interfere with the clearness of the ground plan of the flower. In laboratory study, students cannot do much if any practical work on cross-pollination, but it is well to keep the matter before FIG. 27. — Diagrams of Fuchsia flower. Shading as in Figs. 25 and 26. their attention, particularly in flowers like the Fuchsia, which shows splendid nectar glands, and in irregular flowers where the alighting-place and definite path of the insect can be traced. Something can be accomplished in the laboratory by imitating 244 THE TEACHING BOTANIST with brushes, etc., the operations of the insect in particular flowers. The teacher can find facts on the mode of cross- pollination of many common flowers in Mtiller's "Fertilization," and with this as a basis can make valuable demonstrations to the class. A lecture or talk, illustrated by diagrams, upon this most interesting of subjects will be appreciated and have great meaning at this stage. XVI. The Morphology and Ecology of the Flower. - - Continued 64. In each of the ten flowers supplied, what is the identity of each visible part ? Answer by annotated sketches. Can you trace any special adaptations to cross- pollination ? 65. In the flower clusters, in what positions do the younger flowers stand relatively to the older ? Can any connection be traced between the size of a cluster and the size or number of the blossoms composing it ? What does a cluster probably mean in connection with cross-pollination ? 66. Construct a series of diagrams, using colors, to show the intermediate stages in the development from a simple conical vegetative point of — a. A flower with all parts distinct. b. A flower with superior ovary, but the other parts united into a tube. MORPHOLOGY AND ECOLOGY OF THE FLOWER 245 A B C D FlG. 28. — Diagrams to illustrate the morphology of typical flowers. A, hypogy- nous; B, perigynous ; C, epigynous ; Z>, epigynous with prolonged "calyx tube." Receptacle is dotted; carpels are cross-lined; "perianth tube," or "calyx tube," vertically lined. Sepals, petals, and stamens are unshaded, but may be distinguished by their relative positions. 246 THE TEACHING BOTANIST c. A flower with inferior ovary, but other parts distinct. d. A flower with inferior ovary, but other parts united. Materials. — For Exercise 64 there should be obtained from a greenhouse some of the more special forms of flowers, such as Begonia, Calla, Orchids, Poinsettia, Narcissus, etc., of which the different specialized parts are to be recognized by the student, and reduced to their proper categories of sepals, petals, etc. Of course, only a few of each kind can be had, as they are expen- sive, but they need not be taken apart, or only partially, and by the teacher ; they may be passed from one student to another. To some extent herbarium specimens, especially if prepared for the purpose, could be used instead of fresh mate- rial, but the latter is always best. For Exercise 65 material is best available in summer, but something may be done with greenhouse or even herbarium material. Pedagogics. — Under Exercise 64 comes some good morpho- logical practice, training in the habit of recognizing similarity of original nature under diversity of form. In Exercise 65 some terminology will have its use, but this subject of flower clusters, while of considerable value in classifi- cation, is not of much interest otherwise. Of course, care is taken by the teacher to select the more marked types. Most valuable is the work of Exercise 66. This cannot, it is true, be made from observation, but must be worked out theoretically, as shown on the accompanying diagrams (Fig. 28). The exercise has great value in contributing to ideas of almost mathematical clearness. A student cannot construct these diagrams who does not perfectly understand the mor- phology of the complex flowers. Series a is about like the MORPHOLOGY AND ECOLOGY OF THE FRUIT 247 Scilla, except that it is supposed to have a distinct calyx and corolla, b is not like any of the flowers studied, but is nearest like the Hyacinth except for the distinct calyx and corolla, c is like the Snowdrop, and d like the Fuchsia. This morphology differs much from that in use in the manuals, but is more nearly correct, as shown by embryological studies. XVII. The Morphology and Ecology of the Fruit 67. What is the exact structure and morphological composition of the six dry fruits supplied ? (1) What has become of each of the parts of the original flower, i.e. sepals, petals, stamens, receptacle, ovary, style, and stigma ? (2) How are the carpels or receptacle modi- fied and arranged to form this fruit ? (3) What is the morphology of the new or accessory parts, — wings, etc. ? (4) In what places, morphologically, is the dehiscence ? (5) How are the seeds probably scattered ? Answer by diagrams and drawings as far as possi- ble. Under (2) bring out the leaf or 'Stem homology in each case. 68. What is the exact structure and morphological com- position of the six fleshy fruits supplied ? Answer as for Exercise 67. 248 THE TEACHING BOTANIST 69. Prepare a synoptical essay, not to exceed four hun- dred words, on the Morphology and Ecology of the Flower and Fruit. Materials. - - In part these may be bought in markets, in part must be collected the year before. Typical follicles are Colum- bine, and Larkspur or Monk's-hood ; legumes are green Beans or Peas, or Locust pods ; winged fruits are Maple and Elm ; others are Poppy, Sunflower, Shepherd's Purse. Of fleshy fruits, good kinds are Grape, Tomato, and Orange (especially navel), Apple, Banana, Cherry (canned are good), Strawberry, Cranberry. Many others can be used, but these are particu- larly typical and obtainable. Pedagogics. — This is a very valuable exercise for morphol- ogy. The students cannot, of course, from the fruits alone settle all points of morphology, but they can settle many ; and as for the rest, it will be a most valuable exercise for them to form their hypotheses, and then have these confirmed or other- wise by the teacher, who will supply missing data. This, under rigid control, is a truly scientific procedure, indeed the greatest help of the investigator. Their interpretation will be greatly aided if they are shown pictures of the flowers from which the fruits come, - - that is, if the flowers are not themselves avail- able. The ideal would be for them to have several stages from the flower to the fruit. It will be best to take the fruits up in order, the simplest, i.e. the follicle, first, then the legume, and so on. This must not be made a drawing lesson in still life, at least not in class ; it can be largely worked out by diagrams. Dia- grams which are halfway between the carpels and unmodified leaves are particularly valuable, but, of course, the fruits should be drawn and labelled for structure also. MORPHOLOGY AND ECOLOGY OF THE FRUIT 249 It is not worth while to give students unusual terms, such as sarcocarp, etc., which are not used in descriptive works, but follicle, legume, drupe, etc., should, of course, be supplied as they are needed. The true morphology of the fruit should be taught; e.g. in the Apple, the flesh is mainly receptacle, with a little of it from carpel ; in the Cranberry, it is receptacle, etc. Particularly important is a clear idea of the Cherry, with part of the carpel forming stone and the other part pulp. Something similar to this separation occurs in the Orange, where the skin is sepa- rable ; it is a part of the carpels. The pulp of the Orange is a growth of hairs from the inner (upper) faces of the car- pellary leaves, though these hairs are not unicellular. The whole subject of the morphology of the pulp is of great inter- est ; it originates in a variety of ways. An account of seed locomotion (a subject always of great interest to students) should be taken up here in much more detail than was pos- sible near the beginning of the course. It may be noted here, by the way, that the word " ecology," so often used in this work (spelled cecplogy in the Century Dictionary, and defined there) is coming rapidly into general use to express adaptation of plants and their parts to external conditions. DIVISION II THE NATURAL HISTORY OF THE GROUPS OF PLANTS THIS second part of our course is a study of the Natural History of Plants. It investigates the habits and structure of these organisms, and the relations of their shape, size, color, positions, and cellular texture to their modes of nutrition, growth, reproduction, loco- motion, and protection. Whenever possible the plants are to be observed as they grow naturally and undis- turbed in their native homes. I. The Algae 70. What is the structure and ecology of the Pleu- rococcus ? Your record should bring out clearly : — a. The exact appearance to the naked eye of the organism as it grows under natural conditions, and a description of those con- ditions. Whatever annotated drawings will not bring out is to be added in notes. The exact structure of the organism, not only in two dimensions, but in all three, with ex- pression of the true size. 250 THE ALG.E 25 I c. Both the vegetative and the reproductive parts. d. Ecological connection between structure and habits. 71. What is the structure and ecology of Spirogyra ? Answer as for Exercise 70. 72. What is the structure and ecology of Fucus ? Answer as before. 73. What is the structure and ecology of a typical Red Seaweed ? 74. From your own studies, from the specimens and pictures examined, reading, and other sources of information, concisely describe : — (1) the range of habitat in Algae ; (2) of color; (3) of size ; (4) of shape ; (5) of texture. 75. Prepare a concise essay, not over two hundred and fifty words, on the Natural History of the Algae, emphasizing their ecology. Materials. — The aim is to give first a typical unicellular form, reproducing by fission, and a filamentous conjugating form next. Zoosporic forms can hardly be used for study of processes of reproduction, because of practical difficulties. As this study is more ecological than systematic, it matters little just what forms are taken as long as they are typical. In summer many Algae are available, but in winter I have found 252 THE TEACHING BOTANIST that Pleurococcus and Spirogyra give the optimum resultant between accessibility and representativeness of their respective groups. Pleurococcus may be found on the damp, shaded bricks and flower-pots of any greenhouses, but, since many other Algae occur in those places, it is necessary to examine the material carefully ; it may be obtained also from the bark of trees, on the damp, shaded side, where, as a green film, it is sufficiently familiar. Protococcus occurs in about the same situations, but, as it reproduces by zoospores only, which are extremely difficult to demonstrate, it is less useful. As to Spirogyra, it is a classic object, and good for many purposes. Conjugating and zygosporic material must be secured the au- tumn before (or may be bought from the Cambridge Botanical Supply Company), and, with vegetative material, may be pre- served in formaline. But much better is material kept all winter in a dish or tank in a greenhouse, as it can then be seen of its natural color and appearance. In all cases the material alive and on its natural substratum should be brought into the labo- ratory. Fucus may be collected on the coast in summer and preserved in formaline, or may be obtained alive and fresh at any time of year from the Cambridge Botanical Supply Company on a few days' notice. For its proper study, sections through the conceptacles are needful, and these may be made by the students themselves with a sharp scalpel, the end of the frond being held between two flat pieces of pith. There is no Red Seaweed known to me which is easily obtainable alive in quantity and in condition to show its reproductive parts to students. I have had to use herbarium specimens of various species for the vegetative structure, and to supply the reproductive structures of a typical form from diagrams, using the Kny series for this purpose. The students copy this diagram with explana- tions ; it is not a good principle, but it is better than nothing. THE ALG.E 253 Pedagogics. — Up to the present this course has been con- cerned chiefly with training in botanical principles, using the higher plants as a basis ; information has been subordinate to the cultivation of eye and hand, and to the formation of scien- tific instincts. From this time on, the object is to lead the student to make a close and sympathetic personal acquaintance with the chief kinds of living plants ; information becomes of equal value with training, and the means for acquiring the former is of greater value. It is true that but few kinds can be studied ; hence it is best to select forms as representative as possible of the great leading groups. The aim should be, using a thorough study of these as centres, aided by collections, figures, and reading, to secure, through the medium of their own senses, the impression upon the minds of the students of a clear, sharply lined picture of the place in nature of each group, — what kinds of places it lives in, how it obtains its nourishment and reproduces, and the meaning of the most constant characters of form, color, etc., and how each is related to the other groups. There are so many excellent books upon the natural history of the different groups that extended directions are here un- necessary. These books are referred to in Chapter VII, but particularly practical and valuable to the teacher are Spalding's, Barnes's, and Atkinson's works. It is of first importance that students see the forms they study growing alive in their native places, and that they look upon them not inertly, but with active curiosity, which will be the case if the teacher keeps properly before them problems to be solved. Next to this, and supplementary to it, is the study of herbarium, or museum materials, photographs, and prints. If it is not possible for them to see the plants alive and at home, then the teacher should describe to them as 254 THE TEACHING BOTANIST vividly as possible, and with all available illustrations, just where and under what conditions they grow. The compound microscope is, of course, necessary from the start. The representation of the living plant, no matter how small, called for under Exercise 70, a, seems to me most important. Even in Pleurococcus, where a single plant cannot be distin- guished with the naked eye at all, the student gains far more accurate knowledge of the exact place of the organism in nature if he has to draw and describe the appearance of the colonies or masses of it, than if, after a hasty glance at the living form, he confines his studies to magnified images of it. Throughout this study of natural history of plants I regard this representation of the appearance of the entire organism, as it looks alive, as one of the most important of all exercises. Colored drawings are the best, and the fullest scope should be given the artistic talents of students ; but a black and white drawing, with colors, etc., explained in notes, is better than a coarsely or badly colored picture. Exercise 70, b, is also important ; it may be brought out by shading, but also, and for most students better, by imaginary cross-sections. These are of great value for testing the stu- dents' knowledge. Exercise 70, c, is necessary ; they should acquire the habit of seeking for the reproductive parts. Exercise 70, Illustrations. Cloth. lamo. 40 cents. All of the illustrations of the original appear in these selected chapters, which are in no way abbreviated. "A remarkably well printed and illustrated book, extremely original, and unusually practical." — H. W. FOSTER, Ithaca, N.Y. THE MACMILLAN COMPANY, 66 FIFTH AVENUE, NEW YORK. WORKS ON BOTANY. ATKINSON (G. F.).--The Study of the Biology of Ferns by the Collodion Method. For Advanced and Collegiate Students. By GEORGE F. ATKINSON, Ph.B., Associate Professor of Cryptogam! j Botany in Cornell University. Svo. $2.00. BOWER (F. O.). — Practical Botany for Beginners. By F. O. BOWEP, D.Sc., F.R.S., Regius Professor of Botany in the University of Glas- gow. 161110. 90 cents. DARWIN (F.) and E. H. ACTON. — Practical Physiology of Plants. By F. DARWIN, M.A., F.R.S., and E. H. ACTON, M.A. Crown Svo. $i.6o. DARWIN (F.)— Elements of Botany. By F.DARWIN, M.A., F.R.S. With Illustrations. Crown Svo. $1.60. CAMPBELL (D. H.). — The Structure and Development of the Mosses and Ferns (Archegoniatae). By l><>r<;i,As HOUCHTON CAMPBELL, Ph.D., Professor of Botany in the Leland .Stanford, Juniur, University. Svo. $4.50. MURRAY (G.). — An Introduction to the Study of Seaweeds. By GEORGE MURRAY, F.R.S. E., F.L.S., Keeper of the Department of Botany, British Museum. With S Colored Plates and SS other Illustra- tions. 121110. $1.75. A' eg. SETCHELL (W. A.). — Laboratory Practice for Beginners in Botany. By WILLIAM A. SETCHELL, of the University of California. 121110. 90 cents. STRASBURGER (DR. EDWARD), DR. FRITZ NOLL, DR. HEINRICH SCHENCK, and Dr. A. F. W. SCHIMPER. — Lehrbuch der Botanik fiir Hochschulen. With Illustrations. Translated by Dr. II. C. P< »RTER, of the University of Pennsylvania. Svo. $4.50. STRASBURGER (E.). -- Handbook of Practical Botany. Edited from the German by W. HILLHOUSE. Third Edition. With numerous Illustrations. Svo. $2.50. VINES (S. H.). — A Student's Text-book of Botany. By SIDNEY H. VINES, M.A., D.Sc., F.R.S. WTith numerous Illustrations. Cloth. Complete in one volume. $3.75. WARMING (E.). — A Handbook of Systematic Botany. By DR. E. WARMING, Professor of Botany in the University of Copenhagen. With a Revision of the Fungi by DR. E. KNOBLAUCH, Karlsruhe. Translated and Edited by M. C. POTTER, M.A. With 610 Illustrations. Svo. $3.75. THE MACMILLAN COMPANY, 66 FIFTH AVENUE, NEW YORK. -