Popular Science Monthly/Volume 33/July 1888/Botany as it May Be Taught
|BOTANY AS IT MAY BE TAUGHT.|
By BYRON D. HALSTED, Sc.D.,
PROFESSOR OF BOTANY, STATE AGRICULTURAL COLLEGE, AMES, IOWA.
AT the outset, let the reader's mind he free from, any idea that the writer thinks he has found a new or royal road to botanical teaching, or that the method here to be stated is any panacea for the ills which follow as a natural result from the old stereotyped ideas of education. He presents it because it has borne good fruit, and combines some features which he has not known of having been dovetailed together elsewhere. This last reason may only give a wide exposure to his ignorance of the ways of botanical teachers. And yet the fault, if it is a fault, lies in part at the feet of his collaborators in natural history. The thought has often occurred to me that botanists do not say enough about their class-work. There is, of course, a strong incentive to let the labor with students be of secondary importance, and to bend all the energies toward some special end in systematic anatomical or physiological work, and thereby to feel that the space in the journals is only open to things new to science. A person, however, with large classes to carry, which consume the greater part of his time, often wishes that the periodicals contained more hints and suggestions as to the most approved methods of imparting knowledge in a branch of natural history which all advanced teachers agree is passing through the diseases and other dangers and trials incident to childhood. At the present time there are nearly as many ways of carrying a class through a course in botany as there are active teachers in the field. Some experienced teachers begin the study with the unicellular plants, and pass upward to the more complex structures. Others advocate opening the study with the kinds most easily found by the untrained eyes and best illustrating all the parts of a highly organized plant. Still others are quite indifferent to method, and consider the subject nearest at hand as the best to use. There are teachers who cling closely to some text-book, and measure their success by the same yard-stick used by the mathematician. Others go to the opposite extreme, discard all texts, and study only the things themselves. The great end in view in this last method is the teaching of the student to see for himself and to finally become an earnest, thoughtful, conscientious, and independent reader of the great open book of Nature. The writer confesses a strong feeling of preference toward this last view of instruction in botany. He would have his students see and think for themselves, and yet realize that others have gone over the same path and passed far beyond them in every branch of the road they are traveling.
No one but the teacher knows how hard it is to dispossess the minds of some students of the old inherited ideas of learning from books. They take as naturally to memorizing a page of text as young ducks to water. In fact, they come to us with no other ideas of education. Like many other mammalia, they are born blind—to the world of natural objects—and, worse than all, they learn to read before they acquire the power of sight. But, thanks to the Kindergarten system, object-teaching is coming slowly forward, and before many generations pass we may hope to have a natural method of education, because then the youth will have grown up under its vitalizing influence. Until then it may be that each teacher will strive to fit his abilities and notions to those of his pupils, and methods will vary and opinions widely differ. It seems all the more important that the ways and means of instruction should have a place in the journals which deal particularly with the subjects taught.
During the past two years the writer has attempted to lead large classes in the direction which it was hoped would develop individual research. The results have been sufficiently satisfactory to warrant a mention of the plan—not for its newness, but that it may draw out criticisms to be used in improving the method, and to suggest a similar trial by those who are similarly situated. The point, in short, of this paper is to show how a sophomore class of thirty-seven members, in an agricultural college, was, the past year, carried through a term of botany lasting seventeen weeks, and reaching from July 20th until near the middle of November. Three class-room exercises of an hour were held each week, and one afternoon weekly was spent in the botanical laboratory. The class had already taken one full year of botany, with recitation exercises occurring twice per week, and among other work each pupil had made a herbarium of fifty species, collected, pressed, mounted, and labeled by himself. The class was fully up to the average for colleges of this sort, in both years and ability, and contained fourteen ladies and twenty-three gentlemen. No text-book was used, and all formal lectures were dispensed with. The work assigned for the term was placed under five heads, namely: 1, herbarium; 2, economic subjects; 3, orders; 4, topics of research; 5, laboratory work. In the first place, fifty species, neatly mounted on standard herbarium paper, were added to the herbarium of the previous term. Each student in the lecture-room was assigned a chair with a broad table-arm for holding specimens, hand-lens, etc. During the first six weeks the class exercises were devoted to plant analyses. The specimens were collected in abundance by the students, in turn, and from three to five species were classified during the hour. Dried specimens of the several genera under consideration were brought from the college herbarium, and, when a student had completed his determination, he was expected to make comparisons with the authentic herbarium specimens. At the end of the first half of the term each student submitted his collection, in portfolio, and about ten days after it was again brought for the examination. This was entirely oral, with the specimens before the student. Questions were rapidly asked upon a wide range of subjects and varying for different students. Ordinal characteristics, botanical names, habitats, striking peculiarities, comparison of species of same genus, contrasts of genera of different orders, are some of the groups into which the questions fell. About five pupils could be thus quizzed per hour.
If there should be any lack of specimens, owing to stormy weather, or spare moments from any cause, the economic subjects were resorted to for filling the hour. These subjects form the second feature of the work of the term, and were selected in order of importance, and assigned four to each student, who prepared for recitation upon them. Each set of four subjects was made to embrace as wide a range of vegetable products as possible. The following are two fair samples: Camphor, ebony, orange, and tomato; Brazil-nut, flax, opium, and turnip. These topics were looked up in the college library, using several books the titles of which had previously been placed upon the lecture-room blackboard as "books of reference." The value to students of learning how to use encyclopædias and other reference-books in work of this kind is almost as great as that of the actual information gained upon the subjects in hand. The students took full notes of the recitations upon the topics, and the questions for examination, following this work, were such as to require the grouping and classifying of subjects. A list of general questions was placed upon the blackboard many days before the examination, and from this set a number were finally selected as tests. As samples the following may be given: Treat of the leading commercial gums; the tropical fruits; plants grown for their roots; commercial spices; the leading drugs; Iowa's most important food plants, etc.
Besides these economic subjects each student at the beginning of the term selected a natural order upon which to prepare, for the class, a paper of ten to fifteen minutes in length. The economic topics easily prepared the way for this more thorough work upon some particular group of plants. For example, the student who selected the pulse family (Leguminosæ) had the advantage of all the notes upon the various gums, drugs, dyestuffs, precious woods, food and fodder plants of the order. In like manner, the writer upon the grasses and grains (order Gramineæ) or the palm family (Palmaceæ), could use the information previously presented upon any economic subject in his respective group. Limited space prevents the reproduction here of even a part of a single paper, thus prepared, although the desire is strong to do it. Some students exhibited much originality in grouping the most important facts and followed up the work until all the sources of information were exhausted. The views of different authors concerning the relative position and "naturalness" of the orders frequently came up, and many important points in systematic botany appeared for consideration.
Some teachers may think too much time was given to this library-work. Let it be kept in mind that at this same time the field-work upon the collection was being prosecuted. During the afternoon a student may have searched in the field and forest for living, and the following evening hunted in the botanical alcove of the library for the facts concerning an economic topic, or collected notes for a paper upon a natural order. The work outside of the class-room and laboratory was a wholesome and healthful mixture of searching in the open air and among the library-books. The habit of looking up subjects in a list of authorities is exceedingly valuable, and one which many students, of themselves, never acquire. When at the same time they get information upon the most practical of subjects, a double purpose is served. A breadth of view of economic botany is thus obtained which does not come from conning a text-book or listening to a course of lectures.
Each student took full notes upon the orders as the papers were presented in class. At the close an examination was held, which consisted in writing upon six out of ten orders chosen by lot from the whole list. Each student, of course, omitted his own order if it chanced to be among those drawn.
In direct contrast with the work in the library was that upon the topics of research. These subjects were also given out at the beginning of the term, so that observations and experiments could be extended over fully three months of the growing season. This is the fourth branch of the term's work, and was designed to lead the students to become investigators in a small way, and learn to ask questions of and receive answers directly from Nature. How well this work was done can only be determined by a careful reading of the papers prepared under this head. It is impossible to more than indicate the results obtained. In the following notes the topics of research are given within quotation-marks: The student with "The Wild Plants of our (the college) Public Grounds" found one hundred and eight species in thirty-four orders. The paper gave the number in each order; those which were herbs, shrubs, or trees, etc. For example, there were twenty-seven compositæ, ten polygonaceæ, five cruciferæ, ten families with two species each, and thirteen orders with each a single representative. Sixteen were not indigenous. Observations in all intensities of light and darkness led to a paper upon the "Sleep of Plants." The honey-locust proved a good subject for observation upon these nyctitropic or sleep movements. Two papers were upon the germination of seeds. In one those of pumpkins and beans were selected, and in the other corn and peas. These seeds were planted by the students in deep dishes and placed in their windows. A careful record of daily observations and measurements was kept, the idea being for the students to learn how to conduct careful experiments. A large area on the blackboard, covered with neat drawings of young plants in all stages of germination, illustrated this work to the other members of the class. The student with "Plants having Two Kinds of Flowers" first worked independent of any guide, and finally closed his studies with a review of Darwin's book upon this subject, a summary of which was presented to the class. Sufficient study had been given to the subject to greatly increase the interest in the book, and the student volunteered the remark that it was exceedingly valuable reading. The "Flora of the Dry Beds of Streams" was exceptional, because the season had been one of extreme drought. Fifty species were found, and three fourths were plants common to low ground. Many species of the remaining one fourth were found elsewhere on gravelly banks. A few were water-plants which continued to survive. Twenty-two orders and thirty-eight genera were represented. Two topics in difficult systematic work were assigned, namely, to one student "The Solidagos," and to another "The Asters." A key was formed for the rapid determination of the local representatives of these two genera. Good herbarium specimens were prepared of the various species and submitted to the class. We have thirteen species of solidagos, and, of the one hundred and fifty asters in the United States, Iowa has twenty-four, fourteen of which are found in the vicinity of the college.
Several of the topics required microscopic work, and the students with these spent extra time in the laboratory. A microscopic study of "Terminal Buds" revealed the whole plan of a year's growth in such buds as those of the horse-chestnut, where flowers in miniature were so numerous that forty could be counted in a single longitudinal section. "Plant-Hairs" was a subject worked almost entirely in the laboratory. A division was first made into those consisting of a single cell and those with more than one. For convenience of further study the subject was again divided into the hairs of flowers, of leaves, of stems, and of roots. The "Seeds of Cruciferous Plants" furnished the pupil subjects for a study into the minute points of classification in the ordinal key of this very natural order, especially as regards accumbent, incumbent. and conduplicate embryos. The student in charge of "Abnormal Forms in Plants" was able to report a number of monstrosities. All members of the class were expected to contribute, if possible, to this paper upon teratology. A toad-flax (Linaria vulgaris) flower with five spurs instead of one was found; two blossoms of an onosmodium were united into one; a spike of foxtail (Setaria viridis) was divided into seven prongs, and perhaps the most interesting was the finding of many pistils of prairie pink (Phlox pilosa) in which there were four cavities instead of three, the normal number. The ovaries for the whole order Polemoniaceæ, to which the phlox belongs, are tricarpellary, and therefore this is a variation which affects the ordinal description. Under the "Dehiscence of Fruits" the pods and capsules of various plants were studied, including those of impatiens, milkweed, violet, and poppy. Observations were made upon the "sensitive stigmas" of the trumpet creeper (Tecoma radicans), which were found to close in one minute when most active—that is, with freshly opened flowers on a bright, hot day. The "Insects Injurious to Plants" furnished abundance of material for an extended paper, and the investigation of the "Root-System of Corn" enabled a student agriculturally inclined to become familiar, by spade and shovel, with the manner in which the roots of our leading crop are spread in the soil. A contrast between "Grape and Cucumber Tendrils" and a study of "How the Virginia Creeper Creeps" were two subjects which, when specially investigated, enabled the students to become familiar with a number of questions which are not easily answered by a study of books. The "Stipules of Various Plants," when contrasted by making drawings of the living specimens, made a paper of interest to all. The clovers and docks were investigated in particular. The leaf-type of the great rag-weed (Ambrosia trifida) was worked out after an examination of two thousand leaves. An opportunity for some thorough microscopic work was offered in the "Pollen of Ten Kinds of Flowers," and it brought out the difference existing in pollen of the same species as well as contrasts between the fertilizing dust of widely separated orders. "Thickness of Leaves" and the "Polarity in the Compass-Plant" were two topics varying widely in their treatment, one being a general and the other a special topic upon foliage. The "Time required for the Ripening of Seed" was determined in an experimental way. Blossoms of various plants were marked with twine and watched until seeds from them matured. Common purslane required ten days; the cultivated species of the same genus, (Portulacca grandiflora) needed fifteen days, while three times as long was insufficient time for maturing the seeds of Euphorbia hypericæfolia. "The Number of Seeds upon Three Kinds of Weeds" was determined as follows: common dock, 7,556; black mustard, 16,416; and burdock, 36,456. The plants chosen were all average ones. A "Flora of a Stubbie-Field" was that of a few acres where oats had grown. The Compositæ and Gramineæ orders were represented by the largest number of species, and furnished by far the greatest percentage of specimens. Two species of rag-weed and the foxtail grass covered four fifths of the field. However, thirty-five species in sixteen orders were represented. Many of these matured their seeds before September 17th, and nearly all before October 10th. Leaves of young, rapidly growing shoots were compared with those of slow-growing branches of old trees, and gave a good idea of the variability of foliage within the same species, or even the same shrub or tree. "Unequal-lobed Leaves" furnished a topic for the study of seeming irregularity, which is, however, a comparatively constant peculiarity in some species. The time of "Opening and Closing of Flowers"; "Dispersion of Seeds, a Comparative Study of Two Labiate Flowers"; "Five Largest Wild Flowers," "Are our Weeds mostly Annuals?" "Anatomy of the Milkweed (Aslepias) Flower," and "Sensitive Stamens of Purslane," are other topics studied by the class, the results of which were none the less interesting because the length of this paper forbids particular mention of each.
To hold each student to an examination upon the work of all these topics of research was not feasible, therefore the notes taken by each member of the class upon the reports of all others were inspected. This secured a record for each student of all the important features brought out under the topics of research, and also furnished a basis for a class-mark as required by college law.
The closing exercise of the term was upon anatomy. A brief outline of the work done in the laboratory is given below. In way of preface it should be said that the students were entirely unacquainted with the compound microscope at the beginning of the term. The first day was spent in learning how to manipulate the instrument, cut thin sections, etc. The brittle stems of the common purslane are excellent for beginners to practice upon with the razor or scalpel. For the second day pollen of several kinds was studied, and ovaries in transverse and longitudinal sections. Accurate drawings are required of all prescribed work. The flower of the large thistle (Cnicus altissimus) filled the third afternoon. On the fourth day the stem of richweed (Pilea pumila) was studied. This subject is highly recommended to all instructors in vegetable anatomy who have not tried it. The course of each bundle is clearly seen from the outside of the comparatively transparent succulent stem. The duckweed (Lemna) is excellent for small roots and prominent root-caps, and the hairs of the squash illustrate living cells, with nucleus, nucleolus, and circulation of protoplasm. Following these, a comparative study was made of the epidermis, including stomata of leaves of cabbage, corn, lilac, pine, and barberry. Next were studied the root-hairs on seedling clover and the stalked glands of the cup of the cup-plant (Silphium perfoliatum). Internal structure of leaf of stone-crop, lilac, and compass-plant were compared, followed by stem of purslane and maple (one and two years old); pine-wood, medullary rays; endogenous stem of asparagus and young corn, crystals; starch, cork, latex tubes, sieve-cells, and the mucilaginous modification of cell-walls as seen in the outer coat of the flaxseed.
This term is followed by another devoted to laboratory work of a more advanced sort, along with a course of lectures upon cryptogamic botany and vegetable physiology.
The old and, at one time, half-true belief that botany is a simple, useless, frivolous study of blossoms which the simpering girls at fashionable seminaries may be excused for calling a branch of learning, is fast passing away. It is a hopeful sign that even so plain-thinking and practical a class as our best farmers are beginning to realize that it is a pecuniary advantage to know more concerning the structure and habits of their farm-crops. They feel that there are laws which govern the improvement of their grains and fruits as well as of their cattle and sheep. In short, there is a demand for thorough instruction in all that pertains to plant-life, and the question naturally arises in the mind of the teacher. What is the best method of meeting the call made upon him for more light? Whatever the best way may be, it is hoped that the outline herein given approaches a method, pointing in the right direction—one which stimulates to deeper and more independent thought, and begets a spirit of respect for the minutest thing, and a burning love to know the truth as it is revealed in the endless book of Nature.