m (T m m m D m --~7> < - ;iw ( epa) showing cyto- • n fruit • 'dpsii-i(»i cnnunm) . moss (Fiuinriti) showing ranulcs; 2b. a cell m-ar the periphery •nphism and three reserve theinfli -f light have developed :'ruit of ( ! IMPOIMAXI MICRO-CHEMICAL REAGENTS 759 Till. MlCRO-POLARISCOPE 764 Tin SIM ( rRoscopi ix MICROSCOPIC ANALYTICAL WORK 764 I)\RK FII i i> h i.t MIXAI IMX AXD mi. ULI KA-MICROSCOPE 765 M n KI i-Av\i.\ MS 766 BOTANY CHAPTER I PRINCIPAL GROUPS OF PLANTS INTRODUCTORY THERE are four main lines of botanical work now recognized, — namely, Morphology, Histology, Physiology, and Ecology. MORPHOLOGY treats of the form and structure of plants and the subject is sometimes divided into (i) external morphology or organography and (2) internal morphology or anatomy (histol- ogy). The former deals with external characters of plant parts and the latter with their minute inner structure. PHYSIOLOGY may be defined as the study which considers life processes and the condi- tions which influence these. ECOLOGY is the study of the adapta- tion of plants and their parts to external conditions. It is impor- tant to bear in mind, however, that these several departments are more or less interdependent, and that one of them cannot be intelligently studied without a consideration of the problems of the others. For instance, as Goebel states, we cannot under- stand the relation of the external forms of organs without refer- ence to their functions. In other words, form and function have a direct relation ; one influences the other. So, too, in the study of ecology we study the influence of external conditions on plants and these, as indicated above, have a direct influence on physiological processes, and thus the study of ecology merges into the study of physiology on the one hand and into morphology on the other. While this book will deal chiefly with the structure of plants and their parts, still it will be necessary occasionally to refer to some of the characters of plants which properly belong to other departments of botanical study. Basis of Plant Structure. — In order to understand the sig- nificance and relation of the various parts of plants it is necessary 2 A TEXT-BOOK OF BOTANY. to know something of their functions and habits of life as well as of their internal structure. It is desirable at this point to give a brief consideration to the cell, as it is the unit of plant structure. If we make a section of a plant and examine it by means of the microscope, the cut surface presents the appearance of a network, indicating that the tissue is made up of small compart- ments or chambers. ( )ne of those compartments together with its contents constitutes the structure known as the CELL (see Frontispiece). The cell-contents vary greatly in appearance and composi- tion, but in all active or living cells there is always present the substance known as PROTOPLASM. The protoplasm is the basis of all plant structures whether they belong to the lowest or high- est forms ; for by its aid or from it all parts of the plant are developed. Even the cell-wall is a product of protoplasmic activity. The protoplasmic content of the cell consists of several intimately related but more or less distinct portions, — namely, a somewhat thin, semi-liquid, granular portion known as the CYTOPLASM ; a more or less spherical body embedded in the cytoplasm called the NUCLEUS; and frequently, but not always, certain small bodies which are more or less variable in shape called PLASTIDS. these being also embedded in the cytoplasm (see Frontispiece). The cytoplasm and nucleus are sometimes considered together a unit, which is known as the PROTOPLAST. A fuller discussion of the differentiated portions of the protoplasm will be found in ( 'haptcr 1 1. The lowest organisms, as the slime molds, do not have an enclosing membrane, but consist of a naked mass of protoplasm. With this exception plants have an outer wall or membrane. They may consist of a single cell, as in the liacteria, or a chain of cells, as in the filamentous Alg;e, or a mass of cells, as in the majority of plants, and an- accordingly designated as unicellular or multicellular. The cell-wall is composed for the most part of cellulose, but may be modified in \arioiis ways. Nomenclature.- The names for describing plants have been derived for the nuM part from studies of the higher plants, they having exclusively attracted the attention of botanists at first. I 'ut with the light which has been thrown on the relationship PRINCIPAL GROUPS OF PLANTS. 3 of the higher and lower groups of plants by the more recent study of the lower forms the older terminology has been somewhat modified. Thus, for example, we speak of the root and shoot, with its leaves, as the vegetative organs of the higher plants, and in describing the corresponding organs (where they exist) in the lower plants, we either apply these terms directly, or indi- rectly by saying that the latter are root-like, stem-like, etc. On the other hand, we now speak of the sexual organs of the higher plants as antheridia and oogonia (or archegonia) instead of classifying them roughly as stamens and pistils, the latter names being retained but with a different signification. Plant Organs. — Depending upon the fact that the plant re- quires nourishment for its growth and development and that it has also to carry on the work of reproduction or propagation, — i.e., the production of new plants, — we distinguish between vegetative or nutritive organs and propagative or reproductive organs. The vegetative organs, such as the root, stem and leaves in higher plants, manufacture the food necessary for the life of the plant, while certain other more or less specialized organs or cells carry on the work of reproduction. In the lower plants, however, the whole structure is much simpler, and in some instances a cell which performs the work of a nutritive cell at one stage may become a reproductive cell at another, or, as in the case of the unicellular Algae, all the various functions of the plant may be carried on by a single cell. Generally speaking, there are two principal ways in which plants are multiplied or reproduced : ( i ) By CELL DIVISION or cell fission, and (2) by the formation of special cells known as SPORES. In cell division (Fig. 85) the nucleus and cytoplasm of a cell divide to form two new cells or protoplasts, which become distinct by the formation of a wall or cell-plate between the two halves. All growth in plants is dependent upon this method, and in growing parts the cells are said to be in a state of division. Owing to the plasticity of the plant organism, detached portions will often grow and give rise to new plants, as in the case of cut- tings. Growth here as in the parent plant is accompanied by cell division. In some of the lower Alg?e (Fig. 10) cell division is the only method of propagation, and as only the ordinary vegetative or A TKXT-BOOK OF BOTANY. nutritive cells of the plant are involved in the process it is some- times spoken of as vegetative multiplication. In both lower and higher plants, with the exceptions ju-t noted, reproduction is also carried on by means of spores. Fi<.. -. r; ttkrix -.-nata. A, young filament with rhizoid cell (r) ; B, piece of filament ; <', a swarm spore or zoospore with 4 cilia; D, biciliate jent; E. F, G, showing iliflcrrnt stages of union of two gametes; II. :n whirh the i ilia havi- liccn absorl ><.•e-t in shallow, stagnant water with the rela- tively high temperature of the summer months, \\~hen public water supplies are polluted by these blue-green Alga? it has been found that the Alg;e are completely destroyed by the addition of a very small amount of o>ppc-r sulphate to the reservoir. As small a quantity as one part per million is sufficient to accomplish this result, not only killing the troublesome organism.-,, but pre- venting their development for some months to come. A few of the common forms will be considered. Gloeocapsa is one of the simplest of the Blue-green Algae (^ Fig. 6), consisting of spheroidal cells from 0.0035 to 0.005 mm- in diameter, of a yellowish or brownish-yellow color, and usually embedded in gmup- of two or some multiple of four in an olive- PRINCIPAL GROUPS OF PLANTS. A mass of cells after numer- ous divisions, all surrounded by a mucilaginous envelope. GLOEOCAPSA. Single cell just after division. The two daughter cells re- tained in a gelatinous mass. Diameter about 4 microns. A single colony. Diameter of colonies varying from 40 to 290 microns. Single cell showing spiral chromatophore. Length, 14 to 18 mi- ll ROG LENA crons' Heterocyst which divides the filament into smaller filaments. Thick-walled resting cells. Spherical gelatinous masses as found floating in/ponds. About twice natural size. Filamentous colonies coiled within the masses of jelly NOSTOC Part of a single filament. Diameter, 4 to 12 microns. Diameter of filaments, 5 to 50 microns- Decaying cell functioning as a heterocys Filaments, about 10 to 60 micron! in diameter. LYNGBYA FIG. 6. Forms of Cyanophycese or Blue-Green Algae. — Adapted from Engler and Prantl and somewhat modified by Lobeck. io A TEXT-1UJOK OF BOTANY. brown gelatinous stratum, this arrangement clue to the cell divid- ing in all directions. They occur on moist earth, stones, wharf pilings, and even on window panes of greenhouses, thus being distributed in both fresh- and salt-water regions. They some- times form a kind of crustaceous stratum, and sometimes soft, slimy masses sufficiently abundant that they can be stripped by the handful from dripping, partially shaded rocks. Owing to the variation in color and general habit of the plant a great many species have been described, but up to the present time about 60 have been sharply distinguished. Oscillatoria, formerly known as Oscillaria, is the name applied to a simple filamentous blue-green alga (Fig. 6) that is char- acterized by movement from side to side as in a pendulum, due, as has been suggested, to the movement of spiral masses of proto- plasm extending from cell to cell. These filaments consist of a series of disk-shaped cells like a pile of coins placed side by side, the end cell being rounded off and more or less convex. The con- tents are made up of a finely granular substance differentiated into two areas, a dark central nuclear portion, and a peripheral holding the pigment, which may vary from a bluish-green to dark olive-green or even red sufficiently intense to give the water a red color. The filaments vary from o.ooi to 0.005 nim- m diame- ter, though they may attain a size of 0.050 mm. Oscillatoria is usually found on wet, marshy grounds, in ditches among decayed vegetable matter, on wood subject to hot waste from steam engines, around pumps and cisterns, and in greenhouses. It occurs in fresh and salt water. Lyngbya somewhat resembles ( )scillatoria, but does not show any oscillations and the filaments are each provided with a dis- tinct .sheath ( Fig. (>). It forms late in the summer in large tufts. It is of a blnNi-^reen color, forms long filaments, occurring in the late summer upon Xostera and other Alg;e. The groups are Inrge and characteristic and have been given the common name Mermaid's I lair. The cells are about 0.030 mm. in diameter. Uroglena is a fnrm which is more or less oval or pear-shaped, about 0.014 to O.OlS mm. in length, and extruded intn a stalk below, the upper md being provided with two unequal cilia ( Fig. 6). The wall secretes a large aim HUH of mucilage. The organisms PRINCIPAL GROUPS OF PLANTS. n arrange themselves in a radiating sphere, with the cilia at the periphery. Each cell of the colony contains a more or less spiral, yellowish chromatophore, bearing a reddish spot at one end, a nucleus at the centre, and a few vacuoles. The cells secrete a large quantity of oil, which is of an unpleasant, fish-like odor, and is due either to the decay or breaking up of the cells by mechanical means. This breaking up of the cells is the cause of the disagree- able odor occasionally found in public water supplies. Uroglena is found in New England and has been reported as far west as Indiana, and is probably rather widely distributed in the United States. It seems to thrive best in cold temperatures, usually occurring in greatest numbers when the water is frozen over. It multiplies by cell division, which takes place when the colony becomes rather large. It also produces resting spores which enable the organism to survive conditions which would otherwise exterminate it. A closely related organism, Synnra, is responsible for the ripe cucumber odor which was formerly thought to be caused by fresh-water sponges. Nostoc, a form occurring in filaments like a string of pearls, is made up of spherical or elliptical cells, the whole being surrounded by a thick, mucilaginous membrane (Fig. 6). Usually one finds a number of these filaments growing together in a mass which can be seen by the naked eye floating in the water. These masses vary from globular to sub-globular, are irregularly divided or occur in definitely expanded groups. These forms are marked by having two kinds of cells, the one filled with a granular proto- plasmic content, the other being free from protoplasm and some- what larger than the other cells. These latter are fewer in number and are called " heterocysts," which means simply " other cells." At these latter cells the filaments separate, and thus many new colonies are formed. Nostoc is mostly of an olive-green color, but may be dark bluish-green, dark brown, or light yellow or even colorless. It occurs mostly in fresh-water ponds, seldom in brackish water, being found on damp rocks, on mosses and more or less submerged plants, and variously in limestone springs or wet calcareous rocks or on aluminous soil. The colonies vary greatly in size and color, and while some of them may be of microscopic 12 A TEXT-BOOK OF BOTANY. size at one period, later they may be as large as peas or cherries. Owing- to their variation in appearance in different seasons various names have been given to the same form by different investigators. They are also associated with lichen-. According to systematists, the forms of Nostoc are arranged according to their aquatic or terrestrial habits. SCHIZOMYCETES, OR BACTERIA.— The Bacteria, or Fission Fungi, occupy rather an anomalous position, some writers classifying them with Fungi and some with Alga?. They are i- celled plants, microscopic in size, and of various shape. The con- tents consist of protoplasm and a central body in some cases, which is looked upon as a rudimentary nucleus. They are more or less colorless, but sometimes produce a distinct pigment called bacterio- purpurin which is rose-red or violet, and occasionally a chlorophyll- green color substance. They are capable of multiplying by division in one. two, or three directions, and under favorable conditions in- crease very rapidly in number. The wall is more or less albumin- ous in character, in this respect resembling the wall of the animal cell, and is provided with one or more cilia, or flagella, the number and position of which have been used as a basis of classification. Sometimes the walls of the cells become mucilaginous, so that the bacteria hold together, forming a mass known as a zooglcea. I'.acteria may form resting spores which arise in two ways. In one case the contents round off and take on a membrane forming a so-called EXDOSI-OUI; ; in the other case the plant body is trans- formed directly into a spore known as an ARTIIROSPORE, as in some of the Blue-green Alga?. This body is not strictly a spore, but is in the nature of a resting cell (Fig. 71. Two classes of bacteria are frequently distinguished, as follows: Aerobic, or those which require oxygen for their development and conse- quently- i^row best when they have access to air or oxygen; and anaerobic, or those whose development is accelerated under re- vci>e conditions, as in underlying tissues or in the interior of cultur Occurrence. — 1'acteria occur everywhere in nature, and play a most important part in decay and putrefaction, in that they change dead animal and plant tixues hack again into simple inor- ganic substances, as carbon dioxide, hydrogen, water, ammonia, PRINCIPAL GROUPS OF PLANTS. 13 etc. They serve a useful purpose in many technical operations, as in the making of cheese, acetic acid, fermentation of tobacco, curing of vanilla and many vegetable drugs, and in soil nitrification, helping to change ammonia into nitrates — one of the sources of the nitrogen used by plants. Many of them are disease-producing, or pathogenic, and are the cause of a number of infectious dis- eases in man and the lower animals, and plants as well. They are FIG. 7. Bacillus subtilis (hay bacillus), a, Small rod-like organisms such as are found in an infusion of hay, or bouillon; b, zoogloea or mass of bacilli forming the "skin" on the surface of infusions; c, chains of organisms forming spores; d, individual bacilli showing flagella, which are only seen after staining. — After Migula. injurious in two ways : in one case they consume the tissues of the host, as in tuberculosis, and in the other they produce powerful poisonous substances, or toxins, as in diphtheria. Classes of Bacteria. — In order to study Bacteria they are grown upon nutrient media, such as sterile bouillon, potato, milk, etc. They are divided into a number of classes, depending for the most part on the shape of the cell: (i) The Spruerobacteria, or Cocci, are those whose cells are spherical or spheroid, and in 14 A TEXT-BOOK OF BOTAXY. which division takes place in one, two, or three directions of space. Very few of this group are provided with cilia. According to the number of cells in a colony they are distinguished as Micrococci, Diplococci, etc. (2) Bacteria proper are elongated, rod-shaped organisms in which division occurs in only one direction, namely, transversely to the long axis, and only after a preliminary elon- gation of the bacterium. The Bacteria are subdivided into two important groups, namely, Bacterium and Bacillus. The Bacilli are motile organisms and produce endospores (Fig. /), whereas the Bacteria are non-motile and do not usually produce endospores. (3) Spiral bacteria constitute the third principal group and are characterized by the cells being spirally coiled. Division is in only one direction. These bacteria are usually motile, and seldom produce endospores. (4) There is another important group which includes the Sulphur Bacteria, of which the most common one is Bcggiatoa. These occur in long threads, and move in an undulating manner much like Oscilluria, one of the Blue-green Algae. They are found in sulphur waters, as in sulphur springs, and contain sulphur granules. Bacteriological Technique. — Principally because of the minuteness in size of micro-organisms a different technique is required in their study from that required in the study of the higher plants. In the first place it is difficult to isolate them so as to be able to study individual forms. Another difficulty is to prevent contamination after they are isolated. And even though a pure culture is obtained it is difficult on purely morpho- logical grounds to differentiate the various forms, as they are all so much alike. 1. \\'hile it is comparatively easy to prepare a sterile solution, — that is, one in which all life is absent, — it is very difficult to prevent subsequent contamination under ordinary conditions. Kven when a cork- or glass-Stoppered bottle for keeping liquids is used it is difficult to prevent the entrance into and development of micro- organisms in the liquids. The use of stoppers consisting of plugs of absorbent cotton was first suggested by Schroeder and von I hisch in 1^54. They found that if llasks containing liquids, which under ordinary conditions wciv likely to decompose, as beef broth, etc., were stoppered with plugs of absorbent cotton PRINCIPAL GROUPS OF PLANTS. 15 and the liquid then boiled for some time it would keep indefinitely. II. It remained for Koch and Pasteur to show what took place in the boiling of the liquid, who at the same time developed the principles of sterilization in bacteriological work. These authors discovered that micro-organisms have two stages of de- velopment, one of which is active and the other resting, the latter being known as the egg or spore condition. They found that the organisms in the active condition were completely destroyed on heating the solution containing them for 30 minutes at 100° C. If this solution was allowed to stand for 24 hours or longer there would be evidences of decomposition, which was due to the fact that the spores representing the resting stage of the organ- isms were unaffected by the first heating and developed into the active stage. As a result of further experiments they found that if the solution were heated on the second day for 30 minutes at a temperature of 100° C. the second growth of organ- isms was destroyed, but it was found that the solution might still undergo decomposition in the course of time, owing to the later development of a few remaining spores. It was, however, found that heating the liquid again on the third day was sufficient to kill all of the spores as well as the organisms in the active stage. By repeating these experiments the authors confirmed theii observations and established the process known as discontinuous sterilization, which simply means that if a solution of a putrescent or fermentative substance is heated on three consecutive days for 30 minutes at a temperature of 100° C., the flask or bottle being stoppered with absorbent cotton, it will keep indefinitely. Instead of using a plug of absorbent cotton the neck of the flask can be drawn out into a narrow tube and directed downwards (see Re- agents). The time required for producing a sterile solution, — that is, one free from micro-organisms or their spores, — can, however, be much reduced by increasing the temperature, or pressure, or both. By use of the autoclave, in which the pressure can be increased from 10 to 20 pounds, sterilization can be accomplished in 30 minutes by using a temperature of 110° C. III. As already indicated, one of the greatest difficulties is to isolate the organisms. In a cubic centimetre of water there 16 A TEXT-BOOK OF BOTANY. may be a million organisms representing various groups of bac- teria. In trying to solve the problem of their separation it occurred to Koch that if he could secure a medium which was solid at the ordinary temperature and liquid at a slightly higher temperature, he could mix a certain quantity of liquid containing micro-organisms with the medium in a sterile condition, and then by solidifying the mixture the organisms would be fixed, and thus from each organism a colony would be developed which could be isolated and further studied. \Ye are indebted to Koch for the use of solid culture media like nutrient gelatin and nutrient agar in the study of these organisms. IV. The application of stains for differentiating the various organisms was introduced by \Yeigert in 1877. Staining is of use in the determination of the number of flagella of certain organisms, in the study of spores, and the identification of certain pathogenic organisms, which occur in mucus and pus, as tubercle bacilli, etc. Gram's method of staining is of great use in differentiating many pathogenic as well as non-pathogenic organisms, and is of importance in classifying bacteria. Characteristics. — Algae are characterized by their habit of li ving in water or in moist places. They vary from simple, I -celled microscopic forms to those of great size like the sea-weeds. In the various types, however, the cells show little variation in shape. All the Algae contain more or less of a green coloring matter, even though it may be concealed by other pigments of a blue (as in Schizophyta), brown, or reddish color. The possession of this L,Teen cell-content or chlorophyll enables the Algae, in the presence of sunlight, to manufacture food substances from simple materials like carbon dioxide and water. The occurrence of chlorophyll can be readily demonstrated by extracting it with 05 per cent, alcohol. Even in the most delicate of the red Al^;e it can l>e shown by placing the fresh material in :i strong solution of common salt and afterwards extracting the chlorophyll with alcohol, the other pigments being unaffected. Alga: are sometimes grouped as Fresh-Water Algae, includ- PRINCIPAL GROUPS OF PLANTS. 17 ing most of the Green Algae, and the Marine Algae or Sea-weeds, including most of the brown and red forms. Algae are classified in three natural groups, not only on account of color differences, but because of certain corresponding struct- ural relationships, thus : Chlorophyceae (Green Algae). Phaeophyceae (Brown Algae). Rhodophyceae (Red Algae). Arranging the Algae in this way provides the simplest classi- fication. But in addition to these groups there is another some- what isolated group that will be taken up first before the Chloro- phyceae,— namely, the Conjugatae. These are Green Algae con- sisting of either single cells or a chain of cells united into threads and further characterized by dividing always in the one direction so that a filament results. They furthermore do not produce zoospores, but produce zygospores as a result of a union of two similar or only slightly different cells. After a period of rest they break from the outer membrane and develop directly into new vegetable cells. To this class the Desmids and Spirogyra belong. The Desmids are unicellular Algae, varying from torpedo- shaped to variously branched forms, occurring even in chains. The protoplast is usually separated at or near the middle, where the nucleus is located, dividing the cell into two symmetrical por- tions (Fig. 8, E). In the protoplast is a more or less complex chromatophore, through the center of which are distributed a number of globular pyrenoids. The latter are distinct structures embedded in the chromatophores of Green Algae and consist of a central protein substance surrounded by a number of starch grains, and, therefore, give a purple reaction with iodine. Owing to the fact that the Desmids -are motile they were formerly con- sidered to be members of the animal kingdom. The movement is slow and steady and largely influenced by the light. There is also a circulatory movement frequently observed in the contents of active living material. In addition, there is almost always observ- able at the ends a well-defined spherical vacuole containing numerous small crystals of calcium sulphate which exhibit a dancing movement due to surface tension and is known as molec- iS A TEXT-BOOK OF BOTANY. ular or Brownian movement. Reproduction is either by simple division or by the union of two Desmids. In the latter case the contents of each flow together into a connecting tube formed by the union of the two Desmids, the resultant mass rounding off to form a zygospore. I'M.. 8. Forms of Desmids in longitudinal view and transverse section. A, Meso- tcenium i-raunn; B. A >n yimi,-rn,i \<>rden^kii>ldii; C. Penium digitus; D, Cylindrocystis crassa; E, C 'lustcrium m«nilif>-rum; F , Spimt.inia muscicola; G, Pleurotcenium trabecula; H, a Docid- ntm {minium; H;i'. D. dilatutum. — From Wille in Engler and Piantl's "Die Naturlichen inzenfamilien." Spirogyra. — Another one of the common Green Algae is Spinujyni ( \:ig. HYCE.i:.--The Chlorophyceae, or Green Algae, are dis- tinguished by usually having a green color, due to chlorophyll, and by having no other pigment. The cells contain one or more nuclei. They are either unicellular or made up of many cells forming fila- ments or flat sheets. They occur either singly as simple cells or in groups representing a single individual or a colony. They are found mostly in fresh or salt water, usually being microscopic in size so as not to be noticed, but often attracting attention when they occur in sufficient quantity to form a scum on the surface. The reproduction is mostly by ciliated cells called zoospores or -warm spores. Reproduction also takes place by the union of the zoospores and through the fertilization of egg cells. The sexual spore resulting from this union of like cells (forming a zygospore) or of unlike cells (forming an oospore) seldom develops immediately, but usually undergoes a resting period be- fore growth is continued Protococcus. — One of the commonest of the Green Algae as well as one of the simplest is Protococcus (Pleurococcus) vul- yaris ( Fig. 10). It occurs as a green coating, in both winter and summer, on the moist bark of trees, moist ground, and stone walls, and is a component of some lichens. The plant is i- celled, more or less spherical, and at one stage contains a number of chlorophyll grains which finally unite to form a single plate which lies against the wall and is known as a CHROMATOPHORE. I U sides it contains a considerable amount of oil. An allied species ( Protococcus I'iridis] contains the sugar erythrite. The plant usually reproduces by simple division, — that is, one cell or plant divides to form two. The divisions may continue by the production of another cross wall, so that four cells result. Under favorable conditions, division may take place by the formation of still another wall at right angles to the other two. In this way two, four and finally eight individuals arise which adhere PRINCIPAL GROUPS OF PLANTS. 21 more or loss to one another, thus forming colonies. The number of individuals in a colony depends upon the number of indi- viduals in the colony when division begins and the extent to which division is carried. Thus if there were four cells in a colony to begin with and division took place in three planes, there would be thirty-two cells in the colony at the end of the period. The development of the green coating on the barks of trees, due to the growth of Protococcus and the protonema of mosses, is usually thought to be more pronounced on the north side. This, however, is a slightly false notion. The fact which determines the position of these plants is the quantity of moisture available. The south and southwest sides of trees in the northern hemisphere are exposed to more light and heat and consequently are apt to be drier, with the result that they are rarely covered with coatings of FIG. 10. Protococcus vulgaris. Different stages of division of the cell. — After Wille. Protococcus and mosses. The under side of slanting trees is a very favorable place, as are also the lower slanting surfaces near the ground of large upright trees, because in these places the water is more likely to be conserved. A careful investigation by Kraemer showed a more abundant growth of green plants on the east and southeast exposure, although the north side of many trees showed good growth also. Volvox occurs widely distributed throughout the United States in ponds and pools of fresh water. It is most abundant in warm weather, but also found in midwinter. It appears as a minute spherical colony about }A mm. in diameter, made up of numerous cells, the number ranging from several hundred to many thousand (Fig. n). The cells at the periphery are pro- vided with cilia, so that the colony rolls slowly through the water. Each cell contains a chloroplastid in which starch granules and often a red pigment spot are present. The asexual reproduc- 22 A TEXT-BOOK OF BOTANY. tion is through the formation of daughter colonies within the mother colony, and these after a time develop motile cells like the parent, which swim about and finally escape. A sexual method of reproduction also occurs in which there is a union of cells within the spheres, the resulting cells after germination forming swarm spores that cling together to form a new colony. Hydrodictyon, or \Yater Xet, is a form often very abundant in sluggish and stagnant waters. It consists of a number of cells forming a net, the meshes of which are usually hexagonal or pentagonal in shape, depending on the number of cells outlining them (Fig. n). The cells are all alike, cylindrical in form, attaining sometimes a length of I cm., and usually contain a number of nuclei. The green chromatophore occurs in a plate at the periphery of the cell and usually contains numerous pyrenoids. The asexual reproduction is by means of zoospores which are formed simultaneously in large numbers, sometimes number- ing many thousands in each cell. These zoospores as formed inside of the mother cell show more or less definite movement and arrange themselves finally to form a new net. The sexual reproduction is characterized by several stages, (i) Some of the zoospores are liberated through a pore in the cell- wall of the mother cell and after swimming around for some time pairs of them unite, forming zygOspores. (2) After a resting period each zygospOK- develops 2 to 5 zoospores, which escape into the water and develop into irregular, sharp-angled cells, called polyhedra, which pcr>ist through the winter. (3) When these polyhedra develop. small xonspores are again formed, and these arrange themselves to form a net inside of the polyhedron, which then escapes and increases in size. Vaucheria ( Fig. 12) is another common green alga which may al>o be -elected as showing the habits of this group of plants. The plant has a branching thallus and lives in shallow water or on moist earth, bcin^ attached to the substratum by means of delicate root-like processes sometimes spoken of as rhizoids ( Fig. u. w). In the thin layer of protoplasm lying near the wall are numerous nuclei and small oval chromatophores. PRINCIPAL GROUPS OF PLANTS. 4 Zoospores developing from oospore. Single polyhedron. Net developing inside of polyhedron. OEDOGOXIUM. Three stages in sexual reproduction. HYDRODICTVON ULVA Mature Colony — Diameter 1 mm. A. Egg cell, before fertilization. B. Oospore. C. Daughter colony VOLVOX FIG. ii. Forms of Chlorophyceae or Green Algae. — All adapted from Engler and Pranti except Ulva. Drawn by A. K. Lobeck. A TEXT-BOOK OF BOTAXV. Xumerous oil globules are also found in the protoplasm, and cal- cium oxalate crystals may occur in the cell-sap. Vaucheria furnishes an example of a plant whose interior is not segmented by cell-walls. In other words, the cavity within the outer or enclosing membrane is continuous, and such a plant is said to be coenocytic, — i.e., like a syphon. But it should be borne in mind that the plant contains a great many nuclei, and, as we have seen (page 2), a nucleus with its associated cytoplasm FlG. 12. Vaucheria sfssilis. A, sporangium from which the multiciliate zoospore is escaping; B. resting zoospore; C, D, germinating zoospores with growing point (s) ; E, plant showing root-like organ of attachment (w), spore from which the plant is developing ; F, sh"\ving in addition two ougonia (og) and an antheridium (h). — After Sachs. continues a unit of work. Hence such a plant as Yaucheria is in a certain sense equivalent to a plant having as many uninucleate ri-lls as it lias nuclei. It would probably be better to call such a plant multinucleate rather than unicellular. Reproduction by means of asexual spores is brought about as follows ( Fig. 12, J ) : A cross wall is formed near the end of one <>f the branches, the end portion constituting a sporangium. The o.ntents. including numerous nuclei, group themselves into one large zoospore, which escapes through an opening in the sporan- PRINCIPAL GROUPS OF PLANTS. 25 gial wall, and after swimming about for a time comes to rest and germinates, giving rise to a new plant (Fig. 12, C, D). This large zoospore is multinucleate and multiciliate, there being two cilia for each nucleus, and by some botanists is considered to be an aggregation of numerous biciliate zoospores. It is also of interest to note that the zoospores of Vaucheria appear to arise by a grouping of the cytoplasm and the nuclei already existing in the sporangium rather than by repeated divisions of a single nucleus. Another method of reproduction in Vaucheria (Fig. 12, F) is that by means of oospores, or spores formed by the union of egg and sperm cells. Two special branches are formed on the thallus as short side shoots. One of these branches, known as the oogonium (Fig. 12, og), is somewhat egg-shaped and sepa- rated from the thallus by means of a cross wall. It contains a great many chromatophores and considerable oil, and has a com- paratively thick wall. The apex is somewhat beaked and con- tains colorless protoplasm. The second branch, which is known as an antheridium (Fig. 12, h), is smaller, somewhat cylindrical and curved towards the oogonium. It is also cut off from the thallus by means of a cross wall. The antheridium contains very little chlorophyll, but a great many sperm cells. These are oval or egg-shaped and have two cilia, one at each end. The sperms escape from the apex of the antheridium and enter an opening at the apex of the oogonium, one of them uniting with the egg cell, which then develops a thick membrane, the resulting oospore being a resting spore. Ulva, or Sea Lettuce, is a common form found all over the world, especially in brackish waters. In its usual form it consists of flat, thin, unbranched fronds which are more or less ovate or orbicular in outline and frequently deeply incised, sometimes be- coming linear or even ribbon-shaped (Fig. n). The fronds con- sist of two layers of cells, which are either in close contact with each other or else at maturity separate so as to form a tubular frond. It sometimes occurs in large quantities in the shallow water along our coast, and is conspicuously disagreeable by its resemblance in shape to the swollen intestines of some animal. CEdogonium is a filamentous alga occurring usually in simple unbranched filaments and attached by a disk-like cell or hold- 26 A TEXT-BOOK OF BOTANY. fast (Fig. n). It occurs in meadow pools or ponds, frequently in streams attached to rocks near rapids. The cells are somewhat elongated and contain a large, irregular chromatophore with pyrenoids. Most of the cells are vegetative cells, interspersed among which are the cells producing the spores. Zoospores are produced singly in the cells and are provided with cilia at one end. After swimming about for some time they attach themselves at this ciliated end to a substratum and develop into filaments. Two other types of cells are formed and which give rise either to ougonia, the female organ containing a large egg cell, or to antheridia, the male organ containing many sperms. The union of a sperm with an egg cell produces an oospore with a very thick wall, capable of over- wintering and developing again when con- ditions are favorable. THE C 1 1. \RACK.E, or Stoneworts, is a highly differentiated group that is considered as a distinct class between the Chloro- phyceae and the Phaeophyceae. They stand so entirely by them- selves that many authorities do not consider them as even Algae. They consist of jointed stems, from the nodes of which whorls of from 4 to 10 leaves are developed, and these bear the sexual organs (Fig. 13). In many of the members of this family the cell- wall is incrusted with lime salts. Chara occurs in great masses in the bottom of ponds and shallow lakes. It occurs in sufficient quantity in many places so that the body of water has a distinct orange color, due to the immense numbers of antheridia. The plant is of such luxuriant growth that if single individuals are kept in an aquarium or large glass vessel it will greatly multiply during the winter and persist for many years. In ponds where ( hara occurs larjje quantities of lime are deposited, so that in ancient deposits now exposed to view one often finds imbedded therein the remains of the spore-fruits. In the luiuj cells or intcrnodes there is a large vacuole and a thin layer nf protoplasm containing a central nucleus and a la rue number of oval or lens-.^haped chromatophores. In some forms. especially in Xitella. the inner protoplasmic layer shows a streaming mo\ement. This is very interesting, as a distinct. streaming movement does not occur in most plants and is limited to a few water plants, the staminal hairs of Tradescantia, the leaf PRINCIPAL GROUPS OF PLANTS. 27 hairs of Cucurbita and Urtica and the hyphae or Rhizopus, etc. This streaming movement in plants like Characese, as pointed out by Pfeffer (Physiology of Plants), has in most cases a definite purpose. It is, in any case, always possible that the streaming movement may be an accessory but unavoidable accompaniment of some other form of vital activity. In Chara and Nitella the 6r FIG. 13. Stonewort or Chara. At left showing the habit of the plant with minute reproductive organs on the leaves. At right enlarged view of reproductive organs. A, mature organs showing (a) antheridium, (S) oogonium surmounted at the top by a crown of cells (c) ; b, stem of plant; /3', j3", whorl of leaves, some of which have been removed, as at /3; B, a young antheridium (a), with young oogonium (SK), together with the adjoining cells of the stem; the whorl of leaves not represented. — A, after Wille; B, after Sachs. streaming endoplasm (inner layer of protoplasm) does not cover more than 2 to 3 mm. per minute. The activity of the streaming is influenced by sunlight, oxygen, acids, chloroform, etc. Two kinds of protoplasmic streaming are recognized: (i) in which the movement is confined to the layer enclosing the central vacuole, that is known as ' rotation," and (2) in which the streaming follows more or less irregular paths up and down the strands of protoplasm, crossing the latter, which is called " circulation." 28 A TEXT-BOOK OF BOTANY. Vegetative reproduction is much like that of the higher plants, through the production of root-tubers or bulbils, stem bulbils, and through special branches arising at the nodes. The bulbils are filled with starch and are capable of over- wintering. The sexual mode of reproduction is through the activity of oogonia producing oospores, and antheridia producing antherozoids or sperms. These are adjacent to each other at the nodes, the oogonium forming a central elliptical cell which is surrounded by a crown of cells through which fertilization takes place (Fig. 13). PH^OPHYCE.I-:. — The Phaeophyceae, or Brown Algae, are dis- tinguished by having brown chromatophores. They are mostly found in the colder waters of the ocean, and are either free or attached to a substratum. They vary in size from microscopic organisms to delicate filamentous or cord-like forms, and may be- come of enormous size. Some are called rock-weeds and give the characteristic color to the rocks between low- and high-tide marks. Others are known as " kelps," and these grow near the low-water mark. They vary in color from an olive-green to a brown. The chlorophyll may be extracted by alcohol, leaving the other pig- ments, phycoxanthin and phycophaein. Many of these Algae are rich in iodine, being one of the sources of this element. They also contain large quantities of sodium, and were used at one time in the manufacture of sodium, and have been used to fertilize the soil in parts of Europe as well as in New England. They are more complex in form than the Green Algae, and are distinguished by having hold-fasts which, while not in the nature of true roots, yet serve to hold the plant. They may also develop stems and bear leaf-like structures of many varied forms. Other-- also develop swollen bladders which contain oxygen and which sL-rve to buoy up the plant. Fr< is, or I'.ladder Wrack, is one of the common rock-weeds i I-'ig. 14. /•' I. It gro\v> near the surface of the water, attached to rocks, and produces a regularly dichotomously branching thalhis. Some of the forms in the upper branches produce air bladders which are spherical or slightly elongated and usually in pairs. The margins of the branches are either entire or somewhat serra- The lips of older branches become more or less swollen and are termed receptacles. They are dotted over with minute PRINCIPAL GROUPS OF PLANTS. 29 cavities, called conceptacles, and these contain the reproductive organs. These consist of oogonia and antheridia, which may be FlG. 14. Some common marine algae. A, Laminaria, showing portions of three leaf- like thalli and hold-fast; B, dichotomously branching thallus of Fucus; C, Sargassum, or "gulf weed," showing a thallus resembling a leafy branch, with swollen, berry-like air bladders, which act as floats; D, Dasya, a delicate branching filamentous sea-weed, attached to a blade of eel-grass; E, dichotomously branching thallus of Chondrus, or Irish moss; F, leaf-like thallus of Grinnellia; G, densely, but delicately branched thallus of Polysiphonia. A, B, C are Brown Algae and D, E, F, G are Red Algae. present on the same or on different plants. The egg cells and the sperm cells escape into the sea-water, and after their union an 30 A TEXT-BOOK OF EOT AX Y. oospore results, which, upon finding a favorable resting place, begins shortly to develop into new Fucus plants. The plant contains both iodine and bromine, chiefly combined with salts of sodium and potassium, and was at one time used in medicine. It also contains a bitter principle and a considerable amount of mucilage. . \SCOPH YLLUM, a rock-weed closely related to Fucus, is dis- tinguished from this genus by the fact that the branches are desti- tute of midribs and the spores occur in groups of four instead of eight. The frond is thick and narrow, branching somewhat dichotomously, and at intervals produces large, conspicuous floats, which are broader than the frond. The plants occur from ^ to 2 metres in length. The fruit is found in lateral branches in winter and spring, and in June the receptacles fall off and are sometimes found in immense quantities, covering the bottom of tide pools. LAMIXARIA is one of the common kelps or devil's aprons which inhabit principally the colder seas of high latitudes. They all grow in pools at low-water mark, attached to the rocks and in deep water, and some attain a very large size. The species vary greatly in outline and habit according to the season and place of growth — whether on an exposed or sheltered coast or partly ex- posed at low tide. It consists of three parts (Fig. 14, A)': a long, leaf-like expansion or blade supported by a more or less cylindrical stalk or stipe, which in turn is attached to the rocks by a hold- fast made up of a cluster of fibrous outgrowths. In general the species may be classed in two groups, one in which the frond is ribbon-like or long in proportion to the breadth and not split up into segments, and the other in which the frond is proportionally broader and fan-shaped and laciniate. To this latter belongs the Laminaria d'ujitata. There are some 25 species, distinguished by the arrangement of root-fibres comprising the hold-fast, the structure of the stipe, whether solid or hollow and whether provided with distinct cavities containing mucilage, the shape. especially of llu- l>a-al portion of the lamina, and the char- acter of the margin and the position of the fruit. The growing portion of the lamina is at the base, as in the leaves of the Spermo- phytes. The kelps of tin- Pacific ( )oean are among the largest sea-weeds known, the ( iiant Kelp, Macr<>rv-tis, attaining a length PRINCIPAL GROUPS OF PLANTS. 31 of nearly a thousand feet. Other forms have large floats at the base of the lamina. Reproduction is chiefly by zoospores formed in i -celled sporangia which occur either in dispersed patches or in continuous bands near the centre of the frond. SARGASSUM, or Gulf Weed, grows attached to rocks by means of disk-like hold- fasts (Fig. 14, C). When it is torn from the rocks it is carried into the open ocean by currents such as the Gulf Stream. Sargassum is most highly organized and is represented by a very large number of species. They are found especially in the warmer waters near Australia, Japan and the adjacent coast of Asia, and also in the West Indies and at various parts of the, Atlantic Coast near the Gulf Stream, some occurring as far north as Cape Cod. The plants vary from 15 cm. to nearly 2 metres in length, and consist of a stem-like axis which bears leaf-like branches with a distinct midrib, berry-like air sacs on stalks, and reproductive branches or receptacles. RHODOPHYCE.E. — This includes all the Algae which are of a reddish or violet color. They contain chromatophores in which the chlorophyll is masked by other pigments, mostly red, and known as phycoerythrin or rhodophyll. The red Algae are mostly found in salt water, occasionally in fresh and running water. They are usually found growing upon other plants or variously attached to some substratum. They vary from microscopic forms or very delicate filamentous types to large plants. They are usually composed of a number of cells or filaments which are so closely arranged as to resemble the tissues of higher plants. Many of the cells are connected by strands of protoplasm, giving them a rather characteristic appearance. Others have an in- crustation of lime on the wall. They are mostly found in deep waters of the Tropics. Reproduction is almost entirely by sexual or asexual spores. CHONDRUS, or Carragheen or Irish Moss (Figs. 15, 16), is a common rock-weed found at low-water mark, and in this country is common from New York northward, being extensively col- lected at a few points about 15 to 20 miles south of Boston. The plant varies considerably in color, being more or less green when close to the surface of the water and of a deep purplish-red when growing at some depth. It varies from 4 to 15 cm. in length, and A TEXT-BOOK OF BOTAXY. is attached to rocks by means of a slender hold-fast. The thallus is dichotomously branching, somewhat flattened, but may be quite linear. The fronds show a mucilaginous modification of the cell- walls. In the upper segments occur small differentiated areas, • FlG. 15. Specimen of C Imndrus cnspus still attached to the rock where it was found growing alony the Massachusetts coast. sometimes called sori, of a more or less elliptical outline, which on sectioning are found to be in the nature of sporangia, contain- ing numerous tetraspores ( Fig. [6). The spores are discharged through narrow canals extruding through the more or less com- pact outer layer of the frond. The article found in commerce has the color removed by being bleached through the action of the sun PRINCIPAL GROUPS OF PLANTS. 33 and dews. It shows, however, all the morphological structure of the growing plant. ft?n,weiSSxn;;Rfl6flO(woM6B00oQnflQflpffifl >^non0O^R0^8p3n00^R°Ons.OS.09QSOocc|0Q03[ FIG. 16. Chondrus crispus: A, B, C, D, various forms of thallus; H, hold-fast; F, sporangia; T, transverse section of thallus showing epidermis (E), sporangium with spores (F) ; S, spores separated in glycerin preparation of thallus by pressure on the cover-glass. The spores occur in groups of four (tetraspores) and the tetrad group is about 301* in diameter. In a closely related genus, Gigartina (Fig. 17), which is found in imported Chondrus, the fruit bodies occur in numerous cylindri- 3 34 A TEXT-BOOK OF BOTAXY. cal outgrowths developed on the surface of the fronds. This form is found more abundantly north of Boston than south, but, as Chondnis is collected at Cohasset, Scituate, and other towns south of Boston, it is not seen in commerce in this country. RHODYMEXIA, or Irish Dulce, is one of the commonest red sea-weeds in the North Atlantic ( )cean. usually growing with Fucus, Laminaria, and other Alg?e between tide marks and extending into deep water. The fronds are purplish-red, flat, membra- Fir,. 17. Gigartina mamdlosa, a red sea-weed closely related to Chondrus crispus, showing a dichotomously branching thallus and bearing at the upper part numerous cylin- drical outgrowths in which the fruit bodies (sporangia) are found. — After Kutzing. nareous, 15 to 30 cm. in length, irregularly cleft, palmate or diclmt onions, the margin often being marked with numerous -mall divisions. The sporangia occur in scattered patches im- mersed in the cortical tissues of the frond. It is a common article of ruinim-ive and is said to possess anthelmintic properties. AGAR-AGAR is derived from several of the marine Algre grow- ing along the eastern roast of Asia, notably species of Gracilaria, • irlidiuni. and ( iloiopellis. It is a mucilaginous substance which i- extracted from the sea-weeds, and is used extensively as a PRINCIPAL GROUPS OF PLANTS. 35 culture medium in bacteriology and in other work where a nutrient is desired. It occurs commercially in bundles 4 to 6 decimetres in length, consisting of thin, translucent, membraneous, agglutinated pieces, yellowish-white in color. It is usually brittle, but becomes tough when moistened. It is used in medicine in the powdered FIG. 1 8. Arachnoidiscus Ehrenbergii, a characteristic Diatom found in Agar-agar. — From a photomicrographic negative by J. J. Woodward, Surgeon, U. S. A. form. Under the microscope Agar-agar frequently shows the frustules or siliceous cell walls of diatoms, which are disk-shaped (Fig. 18). It is insoluble in cold water, but dissolves slowly in hot water. Upon boiling i part in 100 parts of water it should yield a stiff jelly upon cooling. Diatoms constitute a large group of unicellular plants, occur- 36 A TEXT-BOOK OF BOTAXY. ring in both fresh and salt waters. They form the plankton or floating microscopic life found in oceans and lakes, which is the source of food of small animal forms inhabiting these waters. The mud at the mouths of many rivers, the sediment of ponds, ditches, and even rain troughs may contain great numbers of these minute organisms. They have been found in the polar ice, and have been detected in the dust evolved from volcanoes. One of the distinguishing characters of the group is that the cell wall is incrusted with silica. For this reason they are practically indestructible and form marls and strata in the earth. They occur either singly or grouped in bands or chains. They are very variable in shape, being boat-shaped, ellipsoidal, spherical, or peculiarly curved in some forms. They are either free or attached to a substratum, as stones, water plants, etc., those which are free having an active movement (Fig. 19). The cell wall of Diatoms practically consists of two halves, one fitting over the other like the lid of a box. These are known as "valves" or " thcca." The manner in which the two valves are joined results in the formation of a ' girdle ' or ' pleura." The girdle is provided with a series of pores conecting with canals at either end and in the middle, through which food from without is supplied to the protoplast. The valves are very often beautifully marked by a series of parallel cross lines, dots, cir- cles, or polygons, which are characteristic of the different groups. Some forms are used in testing the definition of objectives, as Pleurosigma angulatum, in which the lines are one-half micron (0.0005 mm. ) wide (Fig. 19, A). In the Diatoms the protoplasm lies as a thin layer close to the wall surrounding a large central vacuole. The nucleus is sur- rounded by a relatively dense mass of cytoplasm, and occurs in definite positions according to the species. The chromatophores frequently occur in plates which are typical for certain species. They are sometimes greenish-yellow, the color being generally masked by the presence of a brown substance known as diatomin. They frequently contain pyrenoids, which are sometimes asso- ciated with granules of starch. Reproduction takes place by simple division or fission, the two valves separating and a new valve forming on each half to replace PRINCIPAL GROUPS OF PLANTS. 37 the old one. In each case the valve formed fits into the old one, and hence in the case of the smaller valve the new cell or plant becomes smaller than the parent plant, the walls not being able to expand on account of the siliceous composition. In this way the cells of one series gradually, becomes smaller and smaller until a certain minimum is reached, when the plant rejuvenates itself FIG. 19. Diatoms: A, Pleurosigma attenuatum as seen from above; B, Pleurosigma balticum as seen from the girdle side; C, D, E, Fragilaria virescens showing colonies attached to an alga in C, a view of a single diatom from above at D, and a chain of diatoms viewed frorr the girdle side at E; F, G, two views of Navicula viridis; H, I, the formation of auxo- spores in Navicula firma, H showing the exit of the protoplasts and the throwing off of the original valves. — A, B, D, after Van Heurck; C, E, after W. Smith; F-I, after Pfitzer. by the production of spores (auxospores). These are formed in two ways : In one case the valves separate from each other, the protoplast escapes, grows larger and develops a new wall ; in the other case, of which there are several types, two individuals come together, and envelop themselves in a mucilaginous covering. They then throw off their siliceous walls and the protoplasts unite to form a zygospore, which grows until it is three times the 38 A TEXT-BOOK OF BOTAXV. original size, after which it develops a new wall, the larger valve forming first (Fig. 19. //. 1 ). DIATOMACEOUS EARTH, also known commercially as : In- fusorial Earth," or ' Kicselguhr ' (meaning siliceous marl), occurs in extensive deposits, some of these, as the stratum at Richmond, Ya., extending to a depth of 18 feet. These deposits consist of the siliceous walls of the Diatoms, which, owing to their composition, are practically indestructible, and are accumulated in those localities which have favored the growth of the organ- ism. The natural deposit is mined and usually calcined to de- stroy the organic matter, after which it is washed and dried. The article used in pharmacy is further purified by boiling with diluted hydrochloric acid, washing, and calcining. This purified product is known as Terra Silicea Purificata, and occurs in the form of an almost whitish, or light grayish, or light brown powder. It is odorless, insoluble in water and in mineral acids or dilute solutions of the alkalies. Under the microscope mounts made in water or solutions of hydrated chloral show the frustules or siliceous walls of the Diatoms. In the better grades of Diatoma- ceous Earth the entire skeleton with the characteristic markings is o present. Material coming from various localities shows a differ- ence in genera of Diatoms. The exact naming of the species requires the assistance of specialists. In order to avoid confusion it is necessary to bear in mind that there are two and sometimes even three views which may be obtained of the same Diatom. Diatomaceous Earth consists of about 85 per cent, of SiO2, 10 per cent, of water, and 5 per cent, of clay, iron oxide, magnesia, lime, and organic material. Owing to the fact that Diatomaceous Farth is made up of the hollow shells of Diatoms, it has the property of absorbing by capillarity gases and liquids. For this reason it is u-ed in the preparation of dynamite; the highly ex- plo.sive nitroglycerin being absorbed by the diatomaceous shells, rendering the product capable of being handled. \Yhen calcined, it will nbsnrb its own weight of water. It is used in pharmacy for filtering and as a diluent for powdered extracts, etc. Among the technical uses may be mentioned: polishing of metals and woods, insulating -team pipes and electrical insulators, packing of caustic and inflammable liquids, and the manufacture of glass, paper, and PRINCIPAL GROUPS OF PLANTS. 39 soap. It is also used to some extent in dermatology. In India it has been used as a rubefacient. In Sweden, and among the Chinese and Laplanders, Diatomaceous Earth has been used as an FIG. 20. The Algae are put to various uses by the people who collect them. The illustration is taken from an ornament purchased at the Louisiana Purchase Exposition and was made by the Filipinos from various kelps having large, bladder-like floats. edible earth under the name of ' mountain meal ' or ' bread- stone." Humboldt also calls attention to the fact (Aspects of Nature) that the practice of eating earth is diffused throughout the torrid zone, among indolent races inhabiting the finest and 40 A TEXT-BOOK OF BOTANY. most fertile parts of the globe. It is a saying even among the most distant of the different tribes living on the Orinoco, when speaking of anything very unclean, that it is ' so dirty that the Otomacs eat it." ECONOMIC USES OF ALG^:. — Many of the Algae are of use as food, of which the following may be mentioned : Vaucheria fasti- (jiata, Griffithsia coralina, Ccraminm Lourcirii, Chondrus crispus, Gigartina mamillosa, Gelidinm cartilagineum, Gelidium crinalc (yielding agar-agarj, Rhodymenia pahnata (yielding dulse), and several species of Gracilaria (which also yield agar-agar). Some of the sea-weeds are used in the production of iodine, as Dnri'ilhca utilis, Ascophyllnm nodosnm, Fucus vesiculosus (bladder- wrack), Sargassum linijoUum, Laminaria saccharina, Lajninaria digitata, Alaria csculcnta, Rhodymenia palmata, Phyl- lophora membranifolia, Macrocystis pyrifera, and Fastigiaria furccllata. A number of the Algse are also used in medicine, particularly for phthisis, as 1'iicns cartilayincns, Stilophora rhizodcs and Dictyopteris polypodioides. Alaria csculenta and Laminaria digi- tata are used in the making of bougies and tents used in surgery. Owing to the toughness of some of the Algre on drying, the material is used in the manufacture of various articles, as handles for tools from the thick stem of Lcssonia jnccsccns, fishing lines from Chordaria flagelliformis (Fig. 20), etc. FUNGI. The Fungi form a large group of plants which do not produce chloroplasts or any bodies having a similar function. They have not the power of carbon dioxide assimilation, — that is, unlike the Al^.'e, they are unable to manufacture food materials, such as carbohydrates (starches, sugars, etc.), from carbon dioxide and water. Hence they are dependent upon previously formed food products, and may derive their food from living plants or ani- mals, when they are known as PAKASITKS, or from decaying animal or vegetable matter, when they are known as SAPROPHYTES. The living plant or animal atacked by a fungus is known as the host. Fungi arc especially characterized by the habit of arising from spores ami of producing thread-like cells the growing point PRINCIPAL GROUPS OF PLANTS. 41 of which is at the apex. These threads are known as HYPH,£ (singular hypha). They branch and become interwoven, forming a mass or mat known as the MYCELIUM (Fig. 23). The myce- lium constitutes the plant body proper, and absorbs the food material from the substratum, which it ramifies, often causing decay. The mycelium is frequently not visible, and the presence of the fungus is not recognized until the so-called fruit bodies are developed, as sometimes seen in the case of moldy oranges, mildewed linen, and as illustrated by the common mushroom. The mycelium has a cellulose wall which in some cases is modi- fied to chitin, a nitrogenous substance related to animal cellulose and found in crabs and other lower animals. The protoplasm either occurs in a more or less delicate form lining the hyphce and enclosing large vacuoles, or is comparatively dense enclosing numerous small vacuoles. Many Fungi contain color substances which are dissolved in the cell-sap and are of a quite brilliant hue. One of the most interesting classes of substances produced by Fungi is that of the ferments, including the oxidizing ferment allied to laccase. Thev contain also amido-substances related to * ./ lecithin ; fats ; carbohydrates, as trehalose and mannitol ; organic acids, as oxalic, tartaric, malic, etc. ; and calcium oxalate may be present in some cases. Reproduction in the Fungi is chiefly by means of asexual spores, which arise in two ways. In the one case they are devel- oped in a special cell or sporangium at the end of a mycelial thread and are known as ENDOSPORES. In the other case they arise on special hyphae, or directly from the mycelium, and are known as EXOSPORES or conidia. There are also several modifications of these two types of spores, which may be referred to later. Groups of Fungi.- -There are four principal groups of Fungi : 1. Phycomycetes. 2. Basidiomycetes. 3. Ascomycetes. 4. Fungi Imperfecti. The Phycomycetes, or Algal-like Fungi, are so called because they show a certain relation to the Alg?e. The Ascomycetes are distinguished by having a sporangium of 42 A TEXT-BOOK OF BOTANY. a definite shape and size, which is called an ASCUS, and which contains a definite number of spores, which is two or some multi- ple thereof. The Basidiomycetes are the most highly developed Fungi, producing large fruit bodies, such as are seen in mushrooms, toad- stools, and puffballs. They are characterized by producing spores (basidiospores) on special hyphre. The spores are usually four in number, and the spore-producing organ is known as a BASIDITM. The Fungi Imperfecti constitute a group of Fungi which, while having certain natural relationships with the other types already considered, yet do this so imperfectly that they are brought in a class by themselves. The complete life-cycle is not in all cases known, and future studies will probably distribute them among the other principal groups. PHYCOMYCETES: ALGA-FUNGI.— The plant body of the Phycomycetes consists of a mycelium which is unsegmented, more or less thread-like and sometimes considerably branched. Reproduction takes place by means of several kinds of spores, and by reason of the production of two kinds of sexual spores they are subdivided into two important groups. These are (i) the Oomy- cetes, which produce oospores, and (2) Zygomycetes, which produce zygospores. Saprolegnia. — Probably one of the best representatives of the ( )<">mycetes is the group of water molds known as Saproleg- nia, which are aquatic in their habits and are both parasitic and saprophytic, occurring on living fish, insects, crayfish and decay- ing plants and animals as well. The plant body consists of a mycelium which may be simple or branched, sometimes forming a dense mass (Fig. 21, A). Like the alga Yaucheria, it produces both swarm spores (zoospores) and oospores. The swarm spores (Fig. 21, />, C) arc produced in sporangia formed by the pro- duction of a partition wall at the end of a hypha. The sporangia are cither cylindrical or spherical, and contain numerous zoospores which have two cilia at one end. These spores are peculiar in that after their escape from the sporangium they swim about, then come to rest and take on a wall, after which resting period they (K-\elo|> two cilia on the side, again move about, and germi- nate when they find a suitable host. PRINCIPAL GROUPS OF PLANTS. 43 The oogonia and antheridia (Fig. 21, D-F ) are also formed at the ends of hyphae. The oogonia are usually spherical and the wall contains a number of small pores. The contents, which are at first more or less uniform, later develop egg-cells, of which there may be as many as fifty in a single oogonium. The anthe- ridium is more or less cylindrical and contains a somewhat uni- FIG. 21. Species of Saprolegnia: A, mycelium growing out from and surrounding a dead house-fly in a water culture; B, C, sporangia with biciliate swarm spores; D, a num- ber of oogonia containing oospheres; E, F, oogonia and antheridia, in F the tube of the antheridium having penetrated the oogonium. — A-C, after Thuret; D-F, after De Bary. form mass of protoplasm. The antheridium bends toward the oogonium and comes in contact with it, but apparently does not in all cases penetrate it. Nevertheless the egg-cells develop walls and become resting oospores. In Peronospora, one of the Oomycetes, the antheridium (Fig. 22, n) develops a tube which pierces the wall of the 44 A TEXT-BOOK OF BOTANY. oogonium (Fig. 22, o) ; the contents unite with the egg-cell, after which a heavy membrane develops, forming an oospore, which germinates when it finds a suitable host. The plants belonging to Peronospora as well as related genera are destruc- Fii;. jj. A, Cy-stopus candidus; B, Peronospora calntheca. Mycelia (m) with haustoria penetrating cells (z) of hosts. C« ( '<>spore formation in Peronospora: o, oogonium; n, anthe- ridium. At the Ict't the antheridium is in contact with ooKonium; the next stage shows the antherHhr .niuni and discharging its contents; at the right the resulting oospore is shown. — After De Uary. tive to many cultivated plants, constituting mildews or blights, as tlii'M- iK\-urriiig on the lcavc> of hyo.-cyamus, tobacco, anthe- mis. matricaria, aconite, grape vine, lima bean, potato, etc. The group ha- revived the name 'downy mildews' because of the PRINCIPAL GROUPS OF PLANTS. 45 fact that the conidiophores rise to the surface of the leaves where the spores are discharged, forming powdery patches. Black Mold. — A common example of the Zygomycetes is furnished by the " black mold," Mucor Mucedo. The mycelium FIG. 23. B, richly branching mycelium (m) of the mold Phycomyces nitens showing upright hyphae bearing sporangia (g). A, C, D, the common black mold Mucor Mucedo. A, sporangium with columella; C, germination of zygospore (z), with formation of hypha (k), and sporangium (g); D, earliest stages in the development of a zygospore, the hyphal branches (b) showing adjoining ends (a) cut off by cross walls. — After Sachs. of this plant is ccenocytic, thread-like, very much branched, and profusely developed, much like that of Phycomyces nitens (Fig. 23, B). This mold is widely distributed, causing trouble in the spoiling of many sugar- and starch-containing substances in the household, including preserves, syrups, fruits, etc. In fact, a A TEXT-BOOK OF BOTANY. number of species of Mucor have the power of inducing alcoholic fermentation in glucose-containing solutions. They are also commonly found in many aqueous solutions of inorganic chemicals as well as organic substances. Asexual spores are formed at the ends of hyprue which rise into the air. The sporangia are spherical and are cut off from the hyphae by means of a transverse wall which projects upward into the sporangium and which is techni- cally known as the columella (Fig. 23, A). The contents by FIG. 24. I'ezizn Kintlui-in; showing stages in the development of ascospores. In the youngest asci (m, r) there is only one nucleus; this divides into two (s) ; the division is repeated, so that then- m .j nuclei in (t) and 8 in (n). These surround themselves with [in .t'-plasm and a cell-wall (v, w), but the protoplasm of the mother cell or ascus is not entirely used up. — After DC Bary. simultaneous division form numerous i -celled spores, which are di-charged by the bursting of the sporangium wall and distributed by air-currents or the wind. As the name of the group to which this plant belongs indicates, it also produces zygospores (Fig. 23, D). These are formed by hyphal branches which ascend from the substratum. The ends of two branches come together, a transverse wall is formed in each branch, the walls in contact are absorbed, the contents unite, and a spore is formed with PRINCIPAL GROUPS OF PLANTS. 47 three membranes, two belonging to the spore proper and the third being formed by the united hyphae. As would be expected, these spores are quite resistant, being able to withstand unfavorable conditions, and germinate (Fig. 23, C) only after a period of rest. ASCOMYCETES.- -The Ascomycetes are distinguished for the most part, like the other higher Fungi, in having a septate mycelium, i.e., one cellular in structure, and in producing asci FIG. 25. Species of Saccharomyces (Yeasts). A, -S. cerevisice or beer yeast; B, S. Pastorianus; C, S. glomeratus; D, 5. Piculatus: a, vegetative cells reproducing by budding; b, formation of ascospores. — After Reesz. (sacs), which latter are formed at the ends of the branches of the mycelia. Two main sub-groups are recognized, the one producing an indefinite number of spores in asci which are not well developed, and known as the HEMIASCI ; the other producing la definite number of spores, which number is characteristic for each species, in a well-developed ascus, and known as the EUASCI. In the latter group the spores arise by successive divisions of the primary nucleus into two, as shown in Peziza confiuens (Fig. 24). Yeasts. — The simplest of the Ascomycetes is the sub-group known as the Saccharomyces, or Yeasts. The Yeasts do not produce a mycelium, but the plant body consists of a single cell, or a chain of cells, and multiplies by a peculiar process known as ''yeast budding' (Fig. 25, a). From either end of the cell a wart-like process develops, which enlarges until about the size 48 A TEXT-BOOK OF BOTANY. of the original cell, from which it is then separated by the forma- tion of a transverse wall. The cells are spherical, ellipsoidal, or egg-shaped, and in some cases somewhat elongated and hypha- like. In the protoplasm are one or more large vacuoles. In certain of the cells, which may be considered to be asci, two to eight spherical or ellipsoidal spores are produced (Fig. 26). There are a number of different species of Yeasts, some of which FIG. 26. Formation of ascospores in a number of different species of Yeasts, i, Sac- charomyces cerevisia; 2. S. I'usturiunus; .}. .s. intermedius; 4. S. validus. — After Hansen. arc cultivated ; and these latter are of great economic importance on account of their property of inducing alcoholic fermentation. They are also of use in the making of bread, changing the carbo- hydrates in part into carbon dioxide and alcohol, both of which are driven off in the baking. The property of yeast causing the fermentation of a solution PRINCIPAL GROUPS OF PLANTS. 49 of sugar whereby alcohol is formed, was for a long time supposed to be due to the presence of the living yeast cell or to the action of living yeast protoplasm, and hence fermentation brought about by living organisms was distinguished from those fermentative processes where distinct principles such as diastase were involved ; the former being known as ' organized ' ferments, while the latter were referred to as 'unorganized' ferments. lUichner obtained from freshly expressed yeast a nitrogenous substance capable of changing solutions of cane sugar or glucose into alcohol and carbon dioxide. This principle he termed zymase, and it has all of the properties of an enzyme or ferment and behaves exactly as the living yeast cell in a sugar solution. In the living yeast plant zymase is continually being formed and decomposes the sugar which has diffused into the cell. Yeasts are used in the treatment of certain skin diseases, their action being attributed to a fatty substance, ceridine. Other principles found in yeasts as well as extracts are used in the treatment of cancer. Under the name of Xerase a mixture is marketed consisting of 150 parts of dried beer yeast, 20 parts of dextrose, 125 parts of white clay or aluminum silicate, and 3 parts of a mixture of nutritive salts. It is used in the treatment of putrid wounds, ulcers, etc. The ginger beer plant, which is used in England for making a beverage known as ginger beer, consists of a yeast (Saccharo- uiyccs pyriformis) and a bacteria (Bacterium vermiforme). These two organisms live in a somewhat symbiotic relationship, the yeast changing the sugar into alcohol and the bacteria developing lactic acid (see Technical Mycology, by La far). Green and Yellow Mildews. — To the Ascomycetes also be- long the green and yellow Mildews, Penicillium and Aspergillus, so common in the household, the dairy, and the granary. These plants produce profusely branching mycelia which form patches upon or just under the surface of the materials upon which they grow. These areas become soft and spongy and are always white at first. After a time hyphal branches, which are more or less flask-shaped, rise above the substratum, and by a process of division at the end of the branch, or conidiophore, a spore called 4 5o A TEXT-BOOK OF BOTANY. a conidiospore is formed (Fig. 27, A; Fig. 28, A). The process of division at the end of the conidiophore continues from below until a chain of conidiospores is formed. The conidiophore fre- quently branches, so that a fan-like series or group of conidia or • - . FIG. 27. Pcnicillium, a green mildew. A, richly branching mycelium with conidio- phores; B, enlarged view of conidiophore showing chains of conidia; G, D, E, F, successive stages in the development of a peiithecium; G, H, J, development of asci; K, groups of asci containing from 4 to 8 ascospures; L, ascospores seen from the side and showing char- acteristic markings. — After Brefeld. conidiospt'iv- is produced ( Kig. 27, B ; Fig. 28, A ). The conidia are usually -mm- ^hadi- <>f inven, but finally they may become more nr k-ss brown. They arc- thin-walled, quite small, and so light that they float freely in the air. If a colony is inhaled it gives PRINCIPAL GROUPS OF PLANTS. 51 the sensation commonly called the 'smell of mold." They are capable of germinating on almost everything, as old shoes, old paper, as well as on bread and other articles of the household, and are commonly found on " moldy drugs," and may occur in pharma- ceutical preparations, as syrups and infusions, and even in solu- tions of inorganic as well as organic chemicals. Aspergillus (Fig. 28) is distinguished from Penicillium (Fig. FIG. 28. Aspergillus, a yellow mildew. A, conidiophore with enlarged, more or less spherical end, from which the fan-like series of chains of conidia arise; B-E, successive stages in the development of perithecium; F, section through a nearly ripe perithecium; G, groups of young asci; H, a ripe ascus with 8 spores. — A, after Kny; B-H, after De Bary. 27) by the fact that the upper end of the hyphal branch or conidio- phore is somewhat enlarged and more or less spherical. In addition to the conidiospores these Fungi sometimes produce in the fall of the year, particularly when grown upon bread, asci fruits (Fig. 27, C-F ; Fig. 28, B-E}. In this case two fertile ini- tial hyphre wind themselves around each other, after which they become surrounded with sterile branches which form a kind of 52 A TEXT-BOOK OF BOTANY. loose tissue, more or less cellular in structure, that finally develops into a yellowish leathery wall. This body, which may be regarded as a closed ascocarp, is known as a perithecium (Fig. 27, F ; Fig. 28. F}. As a result of the conjugation of the fertile cells, asci ( Fig. 27, G, II, J ; Fig. 28, G, /•/) develop within the perithecium, which are more or less spherical or ellipsoidal and contain from four to eight spores (ascospores) (Fig. 27, K; Fig. 28, H). A fter maturity the cellular tissue around the asci dries up and dis- integrates, the walls of the asci dissolve, and the ascospores are liberated from the perithecium by slight pressure. The spores lie over winter and then germinate, producing a mycelium from which conidia first develop and afterwards the perithecia, thus repeating the life history of the plant. Ergot. — Another Ascomycete of special interest is the fungus known as Ergot (Chn'iccps purpnrca). The spores of this fungus germinate on the flowers of certain grasses. The myce- lium penetrates the walls of the ovary, absorbing the nutriment. After a time the mycelium develops on the surface, and from this short conidiophores arise bearing small ovoid conidia (con- idiospores) (Fig. 29, A ). The mycelium secretes a sweet fluid, the so-called honey dew which attracts insects, and thus the conidia. are carried to other plants. As the conidia are capable of immediate germination the so-called ' ergot disease ' rapidly spreads during the flowering season of the host plants. After the formation of conidia ceases, the mycelium forms a dense mass which is surrounded by a dark layer, and this, if developed upon rye, constitutes the ergot grains (Fig. 29, B) used in medicine, these grains being a number of times larger than the rye grains which they replace. The mycelial tissues connected with the host plant die. and the ergot drops to the ground. At this stage the ergot mass is more or less cellular in structure and is known as the SCLEROTIUM. It is quite resistant and usually remains dormant until the following spring when the grasses are in flower again. The sclerotium then shows signs of renewed activity by the de- velopment of small, reddish, spherical bodies with a fair-sized stalk ( l-'ig. 29, O. Within the periphery of these spherical heads are produced flask-shaped perithecia or ascocarps (Fig. 29, D) PRINCIPAL GROUPS OF PLANTS. 53 containing numerous cylindrical asci (Fig. 29, £), each of which contains eight spores (Fig. 29, F) ; the latter are i -celled, hya- line, and thread-like (Fig. 29, //). These spores are carried by B FIG. 29. Claviccps purpurea. A, mycelium developing conidia; B, an ear of rye with a number of lipe sclerotia replacing grains of rye, and known as ergot; C, sclerotiuni developing spherical fruit bodies; D, fruit body in longitudinal section showing numerous flask-shaped perithecia at the periphery; E, enlarged perithecium with numerous cylin- drical asci; F, closed ascus with 8 ascospores; G, discharge of ascospores; H, single thread- like ascospore. — A, after Brefeld; B, after Schenck; C-H, after Tulasne. the wind to the flowers of certain of the grasses, as already stated, and the life history or cycle of growth begins again. 54 A TEXT-BOOK OF BOTANY. Chestnut Bark Disease is caused by a fungus parasite known as Diaporthe parasitica Murrill, and is said to very closely re- -emble the parasite found in Italy, Endothia radicalis. This fungus has been the cause of very great destruction of chestnut trees in the eastern United States. When any of the spores of this fungus gain entrance into a wound on any part of the tree, thread-like mycelia are developed in the inner layers of the bark, and these spread concentrically until they girdle the trunk or FIG. 30. L.-iri'f Chestnut tree partly killed by the bark disease. Note branches in the center cither killed or bearing dwarfed leaves, and the other larger branches still unaffected. — From photograph by Haven Metcalf. limb, so that if it happens that the trunk is affected the entire tree may die within the year, while if it is the smaller branches which are attacked, only those parts beyond the point of infection are killed, while the remainder of the tree will survive for some years < Fig- 30 V \Yhen the bark is attacked by the fungus it shows minute, more or less crater-like spots of a yellowish-orange or reddish-brown PRINCIPAL GROUPS OF PLANTS 55 color which are pustules of the fruiting fungus. These pustules produce mostly winter spores (ascospores), although occasionally a long strip of summer spores (conidia) are also produced (Figs. 31 and 32). FIG. 31. Typical appearance of branches of Chestnut tree affected with chestnut blight. At left, bark showing pustules of the parasitic fungus bearing winter spores. At right, the diseased bark showing pustules and form of discharge of summer spores in damp weather. — From photograph by Haven Metcalf. The control of the disease over large districts consists mainly in destroying the affected trees and carefully burning the rubbish. A TKXT-BOOK OF BOTANY. Single trees are treated by removing the affected branches and painting over the cut ends with coal tar to prevent reinfection. For further details on this fungus consult: Murrill, " A Xew Chestnut Disease,'' Torrcyu, Sept., 1906; Farmers' Bulletin 467, U. S. Department of Agriculture; Metcalf, "Diseases of the Chestnut and Other Trees. ' Trans. Mass. Hort. Soc., August, FIG. 32. Chestnut-blight disease, which occurs in small yellowish pustules the size f.f a pin head. A, section of pustule showing perithecia; B, asci with sporidia; a, usual form; 1). (<>rm ran.-Iy found; C, sporidia; D, summer spores. — After Murrill. ; l;arlo\v, ' Fungus of the Chestnut-Tree Blight," Science, May io, \()\2. BASIDIOMYCETES.- -The r.asidinmyceies are the most highly organized of tin- l-'ungi. The imcclium consists of white branch- ing threads and is usually concealed in the substratum. In the cultivation of the edible mushrooms propagation is by means of the mycelium, which is known commercially as "spawn." It is recognized. Imwevcr, that mushrooms can not be propagated in PRINCIPAL GROUPS OF PLANTS. 57 this way exclusively for more than two or three years. The my- celium is really the plant body, and the part which rises above the surface and is commonly regarded as the toadstool or mushroom (Figs. 33 to 37) is a fruit branch, or spore-producing organ. When these branches first make their appearance they are in the form of small solid bodies known as " buttons ' (Fig. 33, I-V). J FIG. 33. Agaricus campestris, the common edible mushroom, showing at A on the left mycelium (m) and development of buttons or young mushrooms; I to V, longitudinal sections showing successive stages in development of fruit body; m, mycelium; st, stipe; h, portion between veil (v) and spore-bearing portion (1). The illustration to the right (A, B, C) shows the structure of the hymenium in different degrees of magnification: A, section through portion of pileus showing five of the gills; B, section of a gill somewhat magnified; C, section of gill still more magnified and showing sterile cells or paraphyses (q), and the fertile cells or basidia (s),from each of which arise two basidiospores. — After Sachs. As growth proceeds these bodies differentiate into a stalk-like portion known as the stipe (Fig. 33, st), which is directly con- nected with the mycelium, and an umbrella-like portion borne at the summit of the stalk, called a pileus, which at first is closed down over the stalk, but later expands or opens more or less widely according to the species. On the under surface of the pileus, known as the hymenium, the spores are borne (Fig. 33, A TEXT-BOOK OF BOTAXY. vW 7 FIG. 34. Some common edible mushrooms and a common poisonous one. The fol- lowing are i-ilible: i. ' "ininun Field mushroom (.\^iri,ns campestris); 3, Clavaria flava, jihuit; '), I'ufTli.-ill (I.yfaprrilnn <-yiitlii.i»rnif); 4, Mori-1 (Morchella esculenta); 5, ( 'hantt-r.-llc (Cntithnri-llits < ilnirius); 7, Fairy-rin^ Fungus (Marasmius oreades). Only ont- /IM/SOWOH.S species is shown, namely, 2, the deadly Agaric (Amanita phalloides). fri mi PRINCIPAL GROUPS OF PLANTS. 59 A, B, C). In some cases the under surface is composed of a series of narrow, radiating, knife-like plates, or gills, as in the common edible mushroom Agaricus. On the surface of the gills the basidia or spore-bearing organs arise. The basidia are somewhat swollen terminal cells of the closely arranged hyphse composing the gills, which bear a group of spores on short stalks (Fig. 33, C). Both the basidia and spores (basidio-spores) are of a characteristic size and number for the different species. Several types of Basidiomycetes are usually recognized, de- pending on the manner in which the spores are borne. 1. The Gill Fungi (Agaricaceaej, in which the spores are borne on plates or gills which radiate from the stem to the edge of the cap. 2. The Pore Fungi (Polyporaceae), in which the spores are borne in tubes or pits opening by pores rather than on gills. 3. The Coral Fungi ( Clavariaceae ) , in which the Fungi are coral-like or leaf-like, the surface of the cap or its branches being smooth. 4. The Leather Fungi (Thelephoraceae), in which the spore- bearing surface is smooth or slightly wrinkled. The texture is usually leathery or papery. 5. The Jelly Fungi (Tremellacese), in which the fruiting sur- face is smooth and the cap is more or less jelly-like when wet. 6. The Puff Balls (Lycoperdaceae), in which the cap is a closed ball which breaks open at maturity to release the enclosed spores. 7. The Carrion Fungi or Stink-horn Fungi (Phallaceae) re- semble the puffballs when young, but are ruptured longitudinally, the spores thereby being exposed on the top as a gelatinous mass. Of these seven groups the Gill Fungi are the commonest, and one or two types will be considered, namely, the common edible mushroom and two of the poisonous group, Amanita. Edible Fungi. — Agaricus campestris (common mushroom) (Figs. 33 and 34) is practically the only edible species cultivated in this country. The plant grows wild in open grassy fields dur- ing August and September. It is not found in the mountains to any extent, and is never found in the woods or on trees or fallen trunks. The color of the stipe and the upper surface of the 6o A TEXT-Ilut )K ( )F B< >TANY. FIG. 35. A decaying tree trur' the cause of the death of the tree by the appearance of the several fungi (j>n>l>al>ly .\m,in;tii muscurin). It is not unusual to find trees showing signs of disease and, finally, even dying, and it is not until the death of the tree that the mature fungus makes its ap]» -.nance. For some years the mycelium of the fungus has been working its way into the tissues not only of the bark but of the wood, sapping it of its vitality. When there is no longer any food supply the fungus produces its fruit; the spores, being scattered by either the wind or through the agency of birds, are carried to other trees and find entrance into wounds, where they germinate and repeat their destruction. — From a photograph by Henry Troth. PRINCIPAL GROUPS OF PLANTS. 61 pileus varies from whitish to a drab color, but the color of the gills is at first pinkish and then of a brownish-purple, which is an important character, the color being due to the spores. The stipe is cylindrical and solid, and a little more than half way up is furnished with a membranous band known as the ring. There are no appendages at. the base of the stipe, which anpears to rise P'IG. 36. Edible Boletus (Boletiis edulis), an excellent edible mushroom found in woods and openings in summer and autumn. The cap is 8 to 15 cm. wide, grayish-, yellowish-, or brownish-red, sometimes paler toward the edge, smooth, and more or less convex; flesh whitish or yellowish, or somewhat reddish just beneath the skin; stem white, stout, and often bulbous. — From monograph on Minnesota Mushrooms by Frederic E. Clements. directly out of the ground. Before the pileus is fully expanded a veil extends from its border to the stipe, which when ruptured leaves a portion attached to the stipe, and it is this which consti- tutes the ring. The ring shrinks more or less in older specimens, but usually leaves a mark indicating where it has been formed. Poisonous Fungi.- -There are two of the poisonous group of Fungi which are very common and which have some resem- 62 A TEXT-IK )( )K ( )F UOTAXY. blance to the edible mushroom just described, namely, the fly agaric (Amanita muscaria) (Fig. 38) and the deadly agaric (Amanita phalloides) (Fig. 34). The fly agaric, while more abun- dant in some localities than the common edible mushroom, is FIG. 37. Pale Lenzites (Lenzites betulina), a non-edible lungus common on trunks and stumps throughout the year. The cap is whitish, corky, more or less densely hairy, and marked by concentric grooves; the stem is lacking and the gills are whitish, more or less branched and united. — From monograph on Minnesota Plant Diseases by E. M. Freeman. seldom found in grassy pastures, but more generally in poor soil, especially in groves of coniferous trees. It occurs singly and not in groups. The gills are always white ; the stipe is white, hollow, and provided with a ring at the top, and the base is bulbous, hav- ing f ringy scales at the lower part. The pileus is yellow or orange PRINCIPAL GROUPS OF PLAXTS. N ,--. FIG. 38. Fly Agaric (A manita muscaria), a very deadly mushroom. The cap is bright red or orange, becoming yellow or even whitish in age, roughened with many thick, white angular fragments of the volva; the stem is stout, white, scaly, bulbous, and hollow; volva forming several concentric scaly rings on the bulb; gills free or touching, white or yellowish. This is frequent in woodland, forest, or clearing from June to frost, and is deadly poisonous. — From monograph on Minnesota Mushrooms by Frederic E. Clements. 64 A TEXT-BOOK OF BOTANY. and sometimes reddish; the surface is smooth, with prominent, angular, warty scales, which can be easily scraped off. The deadly agaric (Fig. 34, illus. 2) somewhat resembles the fly agaric and also differs from the common mushroom in not usually growing in pastures. It occurs singly, but not in groups, in woods and borders of fields. The gills and stipe are white, the latter, when young, having a number of mycelial threads running through it. The base is quite bulbous, the upper part of the bulb having a sac-like membrane called the volva. The pileus may vary from any shade of dull yellow to olive, although some- times it is shiny and white. While it does not possess the warty scales found in the fly agaric, it has occasionally a few mem- branous patches. The Toxic Principles in Poisonous Fungi.- -The deadly agaric (Amanita phalloides) is the cause of the greatest number of cases of mushroom poisoning. According to Abel and Ford, it contains two toxic principles: (i) Amanita-hemolysin, a blood- laking principle, which is a very sensitive glucoside, — that is, pre- cipitated by alcohol, destroyed by heating to 70° C. and by the action of digestive ferments; (2) Amanita-toxin, which is soluble in alcohol, is not destroyed by the action of heat or ferments. The latter principle is the important poisonous prin- ciple in mushroom poisoning and is probably the most toxic principle known, 0.4 of a milligramme killing a guinea pig within 24 hours. The majority of individuals poisoned by the ' deadly amanita ' die, but recovery is not impossible when small amounts of the fungus are eaten, especially if the stomach be very promptly emptied, either naturally or artificially." The fly agaric (Amanita niuscaria) owes its toxicity to uius- carinc, an alcohol-soluble crystalline substance. It is supposed by Ford that the fly agaric may contain another poisonous constit- uent. In cases of poisoning atropine has been successfully ad- ministered hypodermically in doses of T-J7 to -£•$ of a grain. It is stated that the A. muscaria, used by the peasants of the Caucasus in the preparation of an intoxicating beverage, is deficient in muscarine. The question as to whether the ordinary edible mushrooms, as distinguished from the poisonous toadstools, may not in cer- PRINCIPAL GROUPS OF PLANTS. 65 tain localities or at certain periods of the year be the cause of fatal intoxication is answered by Ford in the negative. He states (Science, 30, p. 105, July 23, 1909) that there are no authentic cases of poisoning from the black or brown spored agarics, although old and badly decomposed specimens may cause transient illness. Economic Uses of Fungi. — A large number of the Fungi, particularly of the Basidiomycetes, are used for food. There are, however, only a few of these which enter the market. These are derived chiefly from Agaricus campestris (Figs. 33 and 34) and Agaricus arvenis, although some other species of Agaricus as well as Morchella esculenta (Fig. 34, illus. 4) furnish excellent products and are cultivated to a limited extent. The ' truffles ' of the market are tuber-like masses formed under ground, which consist of the ascocarps of certain Tuberaceae, one of the sub- groups of the Ascomycetes, and which are used as a condiment and sometimes roasted like potatoes. Tuckahoe or ' Indian bread ' is also produced under ground and consists apparently of the fungus Pachytna Cocos and the roots of Liquidambar, the tissues of which have been changed into a compound resembling pectic acid by the fungus. Quite a number of Fungi have been used in medicine, as Claviceps purpurea (Fig. 29), Poly poms officinalis and other species, and various species of Lycoperdon. A number of species are used in making surgeon's agaric (Fungus chirurgonun ) formerly used as a haemostatic, including Lycoper- don Bovista and Polyporus fomentarius. Many of them yield very toxic principles, as ( i ) several species of Amanita which contain several toxic principles; (2) Lactarius piperatus and others which yield highly poisonous resinous principles. Other uses of Fungi have been mentioned under the several groups. USTILAGINE^E and UREDINE^'. — There are two groups of Fungi of considerable economic interest which by some writers are classed by themselves, and by others placed with the Basidio- mycetes. These are the Ustilaginese, or Smut Fungi, and the LTredinese, or Rust Fungi. The Smut Fungi are parasitic on higher plants. The myce- lium penetrates the tissues of the host, but does not seem to cause either disease or malformation of the plant. Injury to the 5 66 A TEXT-BOOK OF BOTAXY. host results only after the development of resting spores. The mycelia are hyaline, more or less branched, and finally become septate. They send short branches, called haustoria, into the cells of the host, from which they obtain nourishment. Eventu- ally the mycelium becomes much branched, compact and more or less gelatinous through a transformation of the hyphal walls, forming gall-like swellings or blisters on the host. Spores are formed within this gelatinous mass at the ends of the branches -•- I FIG. 39. Corn smut (Ustilago Maydis) showing several gall-like masses of smut full of spores. of the mycelium. At a later stage the smut loses its gelatinous character, the mass breaks up, and the spores are freed and dis- tributed as a dry. dusty powder. The spores (primary conidia) are somewhat spherical or ellipsoidal, and are generally separate, but are sometimes united into a mass forming the so-called " spore balls." These are resting spores and upon germination (Fig. 40) produce a promycelium or basidium which becomes septate and from each cell of which conidia called sporidia arise. The sporidia are formed in succession one after another and the process con- PRINCIPAL GROUPS OF I'LAXTS. 67 tinues for some time. On germination they bud like yeast, form- ing new conidia, or when nutrition is not abundant they may form a mycelium, which is usually the case when they germinate on a host plant. Corn Smut. — One of the Smut Fungi, namely, Ustilago RIaydis, which develops on Indian corn (Fig. 39), is used in medi- o 10 FlG. 40. Spores of various Smuts. I, Ustilago longissima growing on the reed meadow- grass (Panicularia americana); 2, Ustilago Maydis from Indian corn (Zea Mays); 3, Ustilago Oxalidis on the yellow wood-sorrel (Oxalis stricta); 4, Ustilago utriculosa on the Pennsyl- vania persicaria (PoLygonum pennsylvaniciim). FIG. 4oa. Germination of spores. 5, Ustilago utriculosa, in water, showing promy- celium and sporidia; 6, Doassansia opaca from the broad-leaved arrow-head (Sagittaria latifolia) in water, showing promycelium, sporidia, and secondary sporidia which are falling off; 7, Ustilago Avence from oat (Avena saliva) in horse dung, showing promycelium, and lateral "infection threads" or hyphas; 8, germination of a sporidium of Ustilago Sorghi into an infection thread; 9, small portion of a group of sporidia developed from promycelium of Tolyposporium eriocauli in potato agar; 10, cross-section of epicotyl of broom-corn in- fected by Ustilago Sorghi showing mycelium ramifying through parenchyma cells of the cortex. — After Clinton. cine. It forms rather large gall-like masses on all parts of the plant, including the root, stem and leaves, and both staminate and pistillate flowers. The spores (Fig. 40) are at first a dark olive- green, but on maturity are dark brown. They are sub-spherical, have prominent spines, and vary from 8 to 15 microns in diameter. They do not germinate at once, but on keeping them for six 68 A TEXT-BOOK OF BOTANY. months to a year they germinate readily on a culture medium of potato, and retain their power of germination for years Rust Fungi.- -The Rust Fungi are parasitic on higher plants FIG. 41. Wheat rust (Puccinia graminis). A, teleutospore or winter spore germinating and giving rise to a promycelium (p) and sporidia (s); B, a few leaves of barberry attacked by sporidia which give rise to the aecidia; C, transverse section through barberry leaf show- ing three cup-like receptacles (aecidia) on the lower surface of the leaf containing per- pendicular rows of conidia (aecidiospores) ; D, germinating aecidiospore on wheat; E, wheat plant attacked by aecidiospores as shown by the elongated blotches on the leaves; F, cross section of leaf of wheat showing on the upper surface the rust spores which are breaking through the epidermal layer (r); G, summer spores (uredospores) ; H, teleutospores or winter spores formed on wheat leaf. — After Dodel-Port. and produce a thread-like branching, cellular mycelium, which develops in the tissues of the host. They differ especially from the other Fungi in producing resting spores known as TELEUTOSPORES. PRINCIPAL GROUPS OF PLANTS. 69 These spores consist of one or more cells surrounded by a thick black wall, and they produce the ' black rust ' seen on foliage at the end of the season. Wheat Rust.- -The most important member of the Rust Fungi is Puccinia, of which there are a large number of species that are destructive to economic plants, as wheat, plum, cherry, red cur- rant, etc. The one whose life history has been best studied is the wheat rust (Puccinia graminis), which requires two different plants to complete its life history, namely, wheat and barberry. The Teleutospores, or 'winter spores' (Fig. 41, //), as they are called, because of their carrying the life of the plant over the winter season, consist of two cells. These spores exist on the leaves and stems of wheat over winter, and in the spring they ger- minate (Fig. 41, A). From each cell a mycelium (promycelium or basidium) consisting of two to four cells arises (Fig. 41, A, p), and from the tip of each branch of the promycelium a spore known as a sporidium develops (Fig. 41, A, s). The Sporidia are scattered by the wind, and when they fall on the barberry leaves (Fig. 41, B) they germinate, producing a dense mass or mycelium which penetrates into the tissues of the host. Sooner or later, just within the under surface of the leaf, there is formed a more or less spherical, dense mass, which grows outward, breaking through the surface, forming a cup-like re- ceptacle known as an aecidium (Fig. 41, C). The /Ecidia, or cluster cups, are orange or yellow and are filled with perpendicular rows or chains of spores which arise from the basidium-like mycelium below. The spores, which have received the name sEcidiospores, are somewhat spherical or polyhedral, and contain a reddish-yellow oil. They are scattered by the wind and, falling upon the wheat plant (Fig. 41, E), germinate immediately, form- ing a dense mycelium. At first it produces what is known as a " Summer spore," or Uredospore (Fig. 41, G), giving rise to the reddish-brown spots and stripes on the leaves and stalks of the wheat plant. The Uredospores are i -celled, and are carried by the wind to other wheat plants, thus rapidly spreading the disease. The LTredospores arise in much the same way as the Teleuto- spores (Fig. 41, //), which form brown patches later in the sea- son, and which have been already considered. The Teleutospores /o A TEXT-BOOK OF BOTANY. last over winter on the old wheat plant, and in the spring begin again the life-cycle of the rust. The plant which results from the germination of a teleutospore gives rise to sporidia, which are carried to the barberry leaves where aecidiospores are pro- duced. The latter are then carried to growing wheat, forming first uredospores and later teleutospores. It should be remembered that these are all asexual spores. In regions where there are no barberry plants to act as host the secidiospore stage is omitted. THE FUNGI IMPERFECT:. — The miscellaneous fungi included in this group are of importance because of the great damage which they cause to agricultural crops. The potato scab is an especially destructive pest in New England and in Canada. The scab not only develops on the growing tubers in the soil, but can be spread from a few affected potatoes to a whole bin of clean ones if they come in contact with them. Prevention of this disease usually consists in disinfecting the tubers which are used for seed so as not to carry the minute organisms into the soil. A disease affecting the leaves of the potato and thereby destroy- ing the crop is due to a fungus whose spores, settling on the leaves, germinate and penetrate to the interior through the stomata, finally weakening or killing the plant. Some of the other important forms produce a pink mold on apples, scabs on peaches and other fruits, mold on onions and other garden crops. The blight of ginseng and the blight of cotton, the dry rot of various vegetables and the blotches on many of our common fruits can be traced to the development of these fungi. The study of these forms is a very difficult one, and re- searches are constantly being carried on at the government experi- ment stations, as well as by individual workers. For a description of these forms, as well as many other harmful fungi, consult " Fungous Diseases of Plants," by Duggar. DETECTION OF Fi'xr.us IN HOST. — Unless special means are employed, it is ofttimes rather difficult to trace the mycelial of the fungus in among the cells of the host plant. Vaughan (Annals of the Missouri Botanical Garden, 1914, p. 241 ) has used the stain known as Pianeze Illb ' in differentiation of the fungus from the plant substratum. The host tissue stains green and the my- celium a deep pink. This stain, devised by Dr. Pianeze for the PRINCIPAL GROUPS OF PLANTS. 71 study of cancer tissue, is made up as follows : Malachite green, 0.50 Gm. ; acid fuchsin, o.io Gm. ; ' Martius gelb," o.oi Gm. ; water distilled, 150.00 c.c. ; alcohol (95 per cent.), 50.00 c.c. For use with plant tissues the procedure is as follows : Wash in water or alcohol, stain in the undiluted mixture 15 to 45 minutes, remove excess stain in water, and decolorize in 95 per cent, alcohol to which a few drops of hydrochloric acid have been added. For per- manent mounts, clear with a carbol-turpentine mixture, remove clearing solution, and mount in balsam. This stain is also valuable for staining spores which have been allowed to germinate on the surfaces of leaves. In such cases the killing and tissue-clearing mixture proposed by Duggar is recommended, viz., consisting of equal parts of glacial acetic acid and alcohol. In the study of the rusts, the best results are obtained by the use of Durand's combination of Delafield's haema- toxylin and eosin (Phytopathology, 1911, p. 129). LICHENS. General Characters. — The Lichens are a peculiar group of plants in that an individual lichen consists of both an alga called a GONIDIUM and a fungus. These are so intimately associated that they appear to be mutually beneficial, and such a relation is known as SYMBIOSIS (Fig. 42). The Algae which may be thus associated in the Lichens are those members of the Blue and Green Algae which grow in damp places, as Pleurococcus, Nostoc, Lyngbya, etc. (Fig. 42). The Fungi which occur in this relation belong both to the Ascomycetes and Basidiomycetes, and it is on the characters of the fruit bodies of these particular Fungi that the main divisions of Lichens are based. The Fungi, however, are not known to exist independently of the Algae with which they are associated ; that is, the mycelia of the fungi will not live for any length of time unless they come in contact with suitable algae. In its development the fungus forms a mycelium which encloses the alga, the growth of which latter is not hindered. The two organisms then continue to grow simultaneously, forming lichen patches. A section of a lichen shows a differentiation into several parts (Fig. 43) : a more or less compact row of cells on both surfaces forming two epidermal layers ; and an inner portion 72 A TEXT-BOOK OF BOTAXY. made up of the hyphal tissue of the fungus in which the alga is em- bedded either in a single layer or throughout the mycelium. The mode of growth and branching is influenced largely by the fungus, although in some cases the alga may exert the most influence. In some cases the lichen consists of a thallus which is irregular in outline, growth taking place at no definite point, and in other cases branches which are more or less regular are formed, growth taking place at the apex. FIG. 42. Lichens showing manner of union of algae or gonidia (g) and hyphae (h) of Fungi. A, Protococcus, showing the manner in which hyphae penetrate the cell and in- fluence cell division; B, Scytonema, an alga surrounded by richly branching hyphae; C, chain of Nostoc showing hypha of fungus penetrating a large cell known as a heterocyst; D, fungal hyphae have penetrated the cells of Glceocapsa, a blue-green, unicellular alga; E, Chlorococcum, a reddish or yellowish alga found in Cladonia furcata, the cells of which are surrounded by the short hyphae of the fungus. — A, after Hedlund; B-E, after Bornet. The walls of the hyphae of the fungus comprising Lichens con- sist at first of pure cellulose. In older material the walls undergo more or less modification, being changed in part to starch, mucilage, or fixed oil. There may be also infiltrated among the layers of the wall calcium oxalate, the latter constituent being especially characteristic of the crustaceous Lichens. The most interesting constituents of Lichens are the coloring principles, which are mostly of an acid character and are termed Lichen-acids. They PRINCIPAL GROUPS OF PLANTS. 73 give very striking reactions with solutions of the alkalies and solu- tions containing chlorine. The reaction with iodine solutions is also employed for diagnostic purposes ; some of the Lichens give a blue reaction, while others behave like amylo-dextrin. Groups of Lichens. — According to the manner of growth and the manner of attachment to the substratum, three principal groups of Lichens may be distinguished : namely, ( i ) Crus- taceous Lichens, where the thallus adheres closely to the stones and barks of trees and practically can not be removed without injury; (2) Foliose Lichens, or those which are more or less flattened, somewhat leaf-like and attached at different points 5(3) Fruticose Lichens, or those which are attached at a particular part of the thallus, and form diffusely branching clumps. To this latter group belong Cetraria islaudica or Iceland moss (Fig. 43), which is used in medicine, Usnea barbata and the red-fruiting Cladonias which are so common. Reproduction in the Lichens takes place in several ways. In all of them there is a vegetative mode by means of what are known as SOREDIA. These are small spherical bodies consisting of a group of algal cells, which are surrounded by a mass of hyphae, and which when cut off from the main body are able to grow. Lichens also produce spores of a number of kinds. In the largest group, the one to which Cetraria islaudica (Fig. 43) belongs, the spores are found in special spherical receptacles, known as PYC- NIDIA, which are formed on the teeth of the margin of the thallus. The spores arise from the ends of hyphse at the base of the pyc- nidia and are in the nature of conidiospores. To these spores the name PYCNOCONIDIA has been applied. Cetraria also pro- duces, like many other Lichens, disk-like or cup-shaped bodies at various places on the surface of the thallus, which are known as APOTHECIA and which may be regarded as exposed or open asco- carps. The inner surface of the apothecia is lined with a number of asci as well as sterile cells, the former giving rise to ascospores. Economic Uses of Lichens. — A number of the Lichens are used in medicine, as several species of Cetraria, Pertusaria coui- munis, Physica parietina, Sticta pulmonacea, Evernia fnrfuracca. Some of those used in medicine are also used as foods on account 74 A TEXT-BOOK OF BOTANY. of the gelatinous carbohydrate lichenin which they contain. Be- sides those given, the following may he mentioned : Cladoma rangifcrina (reindeer moss), Lccanora csculenta (supposed to be the manna of the Israelites). The Lichens are, however, chiefly of interest because of the coloring principles which they contain. FIG. 43. Iceland Moss (Cetraria islandica). A-F, various forms of thalli showing apothecia (a); I, cross-section of an apothecium showing the hymenium (h), the hypothe- cium (p), the algal layer (e), the medullary layer (m), and lower or ventral surface (1); K, an ascus with eight ascospores and two paraphyses from the hymenium (h). Raccclhi tuicioria, Lccanora tartarca, and other species of Lcca- nora, yield upon fermentation the dyes orcein and LITMUS, the latter of which finds such "VIRTU! use as an indicator in volu- metric analysis. Cudbear, a purplish-red powder, is prepared by treating the same lichens with ammonia water; while in the prep- PRINCIPAL GROUPS OF PLANTS. 75 aration of orchil, a purplish-red pasty mass, sulphuric acid and salt are subsequently added. A number of species contain a yel- low coloring principle, as Zeora sulpJiurca, Zeora sordida, Lecidca gcographica and Opcgrapha epigcea. ARCHEGONIATES. The two main features which distinguish the Archegoniates from the Thallophytes are the structure of the sexual organs and the distinct manner in which the peculiar phases known as alter- nation of generations are shown. The antheridium or male sexual organ is a well differentiated multicellular body which is either sunk in the adjacent tissues of the plant or is provided with a stalk. Within it are organized the sperms or spermatozoids, which are ciliate and swim freely in water. Corresponding to the oogo- nium of the Thallophytes is the ARCHEGONIUM or female sexual organ which gives name to the group. The archegonium is a flask-shaped cellular body consisting of a basal portion of venter, which contains a single egg, and a neck through which the sperms enter (Figs. 49 and 51). In the life history of this group of plants there are two gen- erations or phases of development. During one stage the arche- gonium and antheridium are developed, and this is known as the sexual generation, and as these organs give rise to gametes or sexual cells it is also spoken of as the GAMETOPHYTE. By the union of the sex cells (sperm and egg) an oospore is formed which germinates at once within the archegonium. That portion of the plant which develops from the oospore gives rise to asexual spores, and hence this phase is called the asexual generation. It is also spoken of as the SPOROPHYTE from the fact that it gives rise to spores. These spores are in the nature of resting spores and do not germinate on the plant as does the oospore. They are distributed and on germination give rise to the gametophyte stage. In some of the Archegoniates these two phases are combined in one plant, as in the Bryophytes, whereas in other members of the group the two phases are represented by two distinct plants ; that is, the gametophyte and sporophyte become independent of each other, as in the Ferns. A TEXT-BOOK OF BOTANY. The following table shows the main divisions and subdivisions of the Archegoniates : f Bryophytes. . . . {Hepatic* (Liverworts). 1 Musci (Mosses). Archegoniates Pteridophytes . . , Filicales (Ferns). Equisetales (Horsetails). Lycopodiales (Club Mosses) BRYOPHYTES The structure of the sexual organs in the Liverworts (Fig. 44) and Mosses (Fig. 49) is essentially the same, but the vegetative organs are more or less dissimilar. In the Liverworts the plant FIG. 44. A common moss (Funaria). A, germinating spores: v, vacuole; w, root- hair; s, exospore. B, protonema about three weeks after germination: h, procumbent primary shoot; b, ascending branch of limited growth; K, bud or rudiment of a leaf-bearing axis with root-hair (w). — After Sachs. body or thallus lies more or less close to the substratum or rises somewhat obliquely, whereas in the Mosses the part we designate as the plant is in all cases an upright leafy branch. The moss plant is said to have a radial structure from the fact that the leaves radiate from a central axis, while in the Liverworts the thallus is dorsivcntral ; that is, as a result of its habits of growth, it is characterized by having a distinct upper and lower surface. PRINCIPAL GROUPS OF PLANTS. 77 The Life History of this group of plants may probably be best illustrated by following that of a moss plant. Beginning with the germination of an asexual spore which is microscopic in size and which germinates on damp earth, there is produced an FIG. 45. A common moss (Polytrichum gracile). A. showing leafy branches (gameto- phores) two of which bear sporogonia, a detached sporogonium (sporophyte) with sporan- gium from which the calyptra (ca) has been detached. B, longitudinal section through a nearly ripe sporangium showing columella (o), the elongated area of sporogenous tissue (archesporium) on either side, annulus (n), peristome (p),lid or operculum (u); C, trans- verse section of sporangium showing columella in center and dark layer of sporogenous tissue (archesporium); D, ripe sporangium (capsule) showing the escape of spores after detachment of lid; E, ripe spore containing large oil globules; F, ruptured spore showing separated protoplasm and oil globules; G, two germinating spores 14 days after being sown, showing beginning of protonema in which are a number of ellipsoidal chloroplasts. — After Dodel-Port. /8 A TEXT-BOOK OF BOTANY. alga-like body consisting of branching septate filaments, which is known as the PROTOXEMA, or prothallus (Fig. 44). The Proto- nema lies close to the surface of the ground and is more or less inconspicuous except for the green color. From the lower por- tion thread-like processes, or rhizoids consisting of a row of cells, are developed, which penetrate the ground. Sooner or later lateral buds arise from some of the lower cells. Growth continues from an apical cell which divides and gives rise to cells that differentiate into stem and leaves, forming an upright branch, which consti- tutes the structure commonly regarded as the " moss plant ' (Fig. 45, A). The leaf-bearing axis varies considerably in size; in some cases it is but a millimeter high, whereas in some species, as Polytrichum (Fig. 45), it may be several hundred millimeters in height. At the tip of the branch the antheridium (Fig. 49, A) and archegonium (Fig. 49, B) are formed. These organs are developed in among the leaves and certain hairy processes, known as paraphyses ( Fig. 49, p). They may both occur at the end of one branch (Fig. 49, C) or they may occur on separate branches (Fig. 49, D), when the plants are said to be monoecious, whereas when these organs occur on separate plants (Fig. 49, At B) the plants are called dioecious. In the case of dioecious plants the plant bearing the antheridium is frequently smaller and less com- plex than the one producing the archegonium. As already stated, the archegonium produces the egg-cell or female gamete (egg) and the antheridium, the sperm cell or male gamete (sperm). The sperms in the Bryophytes are more or less filiform and are provided with a pair of cilia at one end. The antheridia, owing to the peculiar mucilaginous character of the cells, only open when there is an abundance of moisture, when the sperms are discharged and move about in the water, some being carried to the archegonium, which likewise opens only in the presence of moisture. \\ ith the trans fcrral of the sperms to the archegonium and the union of one of these with the egg which remains sta- tionary, the work of the gametophyte may be said to be com- pleted. The act of union of the egg and sperm is known as FERTILIZATION, and when this is effected the next phase of the life history begins. The egg after fertilization divides and re-divides within the PRINCIPAL GROUPS OF PLANTS. 79 archegonium, which becomes somewhat extended until finally it is ruptured. The dividing cells differentiate into a stalk and a spore case or sporangium which is borne at the summit, the whole structure being known as the SPOROGONIUM (Fig. 45). The base of the stalk is embedded in the apex of the moss plant, and is known as the foot, it being in the nature of a hausto- rium or nourishing organ. As the sporogonium develops and rises upward it carries with it the ruptured archegonium which forms a kind of covering over the top, called the calyptra (Fig. 45, ca). At first the sporangium is more or less uniform, but eventually differentiates into two kinds of tissues, the one being sterile and the other fertile (producing spores), which latter is known as the ARCHESPORIUM (Fig. 45, B, C). The fertile tissue in both the Liverworts and Mosses is variously disposed ; some- times it forms a single area and is dome shaped, spherical, or in the form of a half sphere. In other cases it is separated into two areas by sterile tissue. The sterile tissue which extends up into the dome-shaped archesporium, or which in other cases separates the fertile tissue into two parts, is known as the columella (Fig. 45, B, C). The sporangium in the mosses is capsule-like and the spores are distributed in three ways : ( I ) In some cases the capsule does not open, but when it decays the spores are liberated. (2) In other cases the capsule dehisces longitudinally in dry weather, and thus the spores are freed. (3) There is a third method in which the capsule is provided with a lid or operculum which comes off and permits the spores to escape, this being the most common method for the escape of the spores (Fig. 45, D). In the latter instance the mouth of the capsule is usually marked by one or two series of cells, constituting the PERISTOME, which are teeth-like and characteristic for some of the groups of mosses. These teeth bend inward or outward, according to the degree of moisture, and assist in regu- lating the dispersal of the spores. In the sphagnum mosses there is no peristome, but, owing to unequal tension of the lid and capsule on drying, the lid is thrown off, and the spores are sometimes discharged with considerable force and sent to quite a distance (as much as 10 centimeters), in this way insuring their dispersal. The spores (Fig. 45, £) vary in diameter from 10 to 20 8o A TEXT-BOOK OF BOTANY. microns, being sometimes larger. They occur in groups of four in a mother-cell, and the spore-group is known as a tetrad, which is characteristic for the Bryophytes and the higher groups of plants. The spores therefore vary in shape from spherical tetra- hedrons to more or less spherical bodies, depending upon the degree of separation. The contents are rich in protoplasm and oil (Fig. 45, F). The wall consists of two layers, the outer of which is either yellowish or brown and is usually finely sculptured. At the time of germination the outer wall is thrown off, and the protonema develops (Fig. 45, G). The spores may germinate almost immediately, or only after a considerable period. These spores are asexual and each one is capable of giving rise to a new plant. \Yith the formation and dispersal of the spores the work of this generation terminates, and this phase is called the sporophyte or asexual generation, from the fact that it produces spores. Having thus followed the stages of development in the life history of a moss, we see that it is composed of the following parts: (i) The alga-like protonema ; (2) the leafy branch which gives rise to an oospore (sexual spore), and (3) the sporogonium which produces asexual spores. The leafy branch is sometimes spoken of as the gametophore (gamete-bearer), and it and the protonema together constitute the gametophyte or sexual gen- eration, while the sporogonium represents the sporophyte or asexual generation. The protonema sooner or later dies off in most plants, but in other cases it persists, forming a conspicuous portion of the gametophyte. HEPATIC^E. General Structure.- -The Hepaticre or Liverworts (Fig. 46) are usually found in moist situations. The protonema formed on germination of a spore is filiform, and the plant body which develops from it consists of a flat, dichotomously-b ranching thallus, or it may in some of the higher forms differentiate into a leafy branch, as in the leafy liverworts. The thallus, owing to its position, has an upper and an under surface which are some- what different, as in Marchantia (Fig. 46), hence it is said to be PRINCIPAL GROUPS OF PLANTS. 81 DORSIVENTRAL. From the lower colorless surface unicellular rhizoids arise (Fig. 47, h). The upper surface consists of several layers of cells containing chlorophyll which give the green color to the plant. Vegetative propagation may ensue by the lower portion of a branch dying and the upper portion continuing as an inde- pendent plant. Or special shoots, known as GEMMJE, may arise FIG. 46. Dichotomously branching thallus of the common liverwort (Marchantia Polymorpha) showing near some of the margins the cup-like depressions in which gemmae are borne (c), and several archegoniophores (a). either on the margin of the thallus or in peculiar cupules, which, when detached by rain or other means, are capable of growing and producing a new plant. In addition the thallus body produces both antheridia and arch- egonia (Fig. 46) which may arise on special stalks above the sur- face. After fertilization of the egg-cell, which completes the work of the sexual generation of gametophyte, the sporophyte develops, 6 82 A TEXT-BOOK OF BOTANY. producing a sporogonium consisting of a short stalk which is embedded in the tissues of the gametophyte, and a capsule (spor- angium). The latter at maturity dehisces or splits and sets free the spores, which are assisted in their ejection by spirally banded cells called " elaters " (Fig. 48', C-F}. The spores on germination give rise to a protonema which then develops a thallus bearing the sexual organs. As in the mosses, the sporogonium represents the asexual generation known as the sporophyte. Liverwort Groups. — There are three important groups of FIG. 47. Transverse section through the thallus of Marchantia polymorpha. A, middle portion with scales (b) and rhizoids (h) on the under side; B, margin of the thallus more highly magnified, showing colorless reticulately thickened parenchyma (p), epidermis of the upper side (o), cells containing chlorophyll (chl), air pore (sp), lower epidermis (u). — After Goebel. Liverworts: (i) The MARCIIAXTIA Group (Fig. 46), in which the thallus is differentiated into several layers and so somewhat thickened. Another character is the diversity in form of the sexual organs, which range from those which are quite simple to those which arc highly differentiated. In Riccia the sexual organs are embedded on the dorsal (upper) side of the thallus, while in Marchantia they are borne upon special shoots, one, which has a disk at the apex that bears the antheridia, known as the antheridio- phore, and another whose summit consists of a number of radiate PRINCIPAL GROUPS OF PLANTS. divisions and bears the archegonia (Fig. 46) on the lower sur- face, known as the archegoniophore ; these being borne on separate plants. In Riccia, the simplest of the Liverworts, the sporangium is enclosed by the thallus and the spores are not liberated until the decay of the plant. (2) The JUNGERMANIA Group, known as ' Leafy Liver- worts " or " scale mosses," includes those forms which are more FIG. 48. Anthoceros gracilis, one of the liverworts. A, thallus with 4 sporogonia; B, a ripe elongated sporogonium, dehiscing longitudinally and showing two valves between which is the slender columella; C, D, E, F, various forms of elaters; G, spores. — After Schiffner. or less moss-like and develop stems and small leaves. The sporo- gonium has a long stalk and the capsule is 4-valved, i.e., separates into four longitudinal sections at maturity. (3) In the ANTHOCEROS Group (Fig. 48) the gametophyte is thallus-like and very simple in structure, the sexual organs being embedded in the thallus. The sporogonium is characterized by a bulbous foot and an elongated, 2-valved capsule. Like the thallus, 84 A TEXT-BOOK OF BOTANY. it develops chlorophyll and possesses stomata resembling those found in certain groups of mosses and higher plants. MUSCI. In the Mosses the archegonia always form the end of the axis of a shoot, whether this be a main one or a lateral one. As has already been stated (p. 78), the sexual organs are surrounded by leaves or leaf-like structures, known as perichaetia or peri- chaetal leaves, and by hair-like structures or paraphyses, both of which are considered to act as protective organs. Sometimes the groups of sexual organs together with the protective organs are spoken of as the " moss flower." As already stated, the Mosses are both monoecious (Fig. 49, C, D) and dioecious (Fig. 49, A, B), hence a moss flower may contain only one of the sexual organs or it may contain both. Mosses are also characterized by an abundant vegetative propagation. Xew branches are developed from the old. ' Almost every living cell of a moss can grow out into protonema, and many produce gemmae of the most different kinds." Entire shoots provided with reserve material are cut off and form new plants. In this way moss carpets are frequently formed in the woods, or masses in bogs. Moss Groups.- -There are two general classes of mosses: (i) SPHAGNUM forms are those which produce leaves without nerves, and in which the sporogonium does not possess a long stalk or seta. What appears to be the stalk is the prolongation of the gametophyte stem which is known as the pseudodium or " false stalk." These forms are characteristic of wet places. Some of the group, as Sphagnum proper, form " sphagnum bogs." New plants develop on top of the old, which latter gradually die and finally pass into sphagnum peat, which forms thick masses and finds use as a fuel. (2) The TRUE MOSSES are especially distin- guished by the differentiated character of the sporogonium, which not only produces a stalk but also the peristome (Fig. 45, />) , which when present is of great importance in distinguishing the different species. Economic Uses of Bryophytes.- -The investigations on the chemistry of the Liverworts and Mosses have not been very numerous. The constituents which have been found are in the PRINCIPAL GROUPS OF PLANTS. nature of tannin, resins, ethereal oils, glucosides, alkaloids, color- ing compounds, and organic acids like citric, oxalic, tartaric, and aconitic. In the mosses starch and silicon salts are found in addition. Several species of Marchantia and Jungermannia are D FIG. 49. Longitudinal sections through tips of leafy branches of mosses. A, show- ing antheridia (a, b) in different stages of development and paraphyses or cell-threads (c), the apical cell of which is spherical and contains chlorophyll, and leaves (d, e); B, show- ing archegonia (a) and leaves (b); C, section of Bryum showing both archegonia, and an- theridia, paraphyses, and leaves; D, section of Phascum showing archegonia (ar), antheridia (an), thread-like paraphyses (p), and leaves (b). — A, and B, after Sachs; C, after Limpricht; D, after Hofmeister. used in medicine. Of the mosses the following have been found to have medicinal properties: Sphagnum cuspidatum, Grimmia pulvinata, Funaria hygrometrica, Fontinalis antipyretica, and sev- eral species of Polytrichum and Hypnum. 86 A TEXT-BOOK OF BOTANY. PTERIDOPHYTES. The Pteridophytes were formerly known as the VASCULAR CRYPTOGAMS. Like the Bryophytes, these plants show a distinct alternation of generations ; i.e., the gametophyte or sexual genera- tion alternates with the sporophyte or asexual generation. Their relation is, however, somewhat changed. In the Bryophytes the gametophyte is the most conspicuous and is looked upon as con- stituting the plant proper, whereas in the Pteridophytes the gametophyte is rather insignificant in size, while the sporophyte constitutes the generation or phase which is ordinarily regarded as the plant. In the higher members of the Pteridophytes the sporophyte is entirely detached from the gametophyte and is able to lead an independent existence. This group also shows a dis- tinct advance in structure. There is a differentiation into root, stem, and leaves, and the development of a system of conducting tissue known as the VASCULAR SYSTEM. The Pteridophytes include three principal groups, namely, ( I ) Filicales or Ferns, (2) Equisetales or Scouring Rushes, and (3) Lycopodiales or Club Mosses, which differ considerably in general appearance and general morphological characters. \Yith the exception of the sperms in the Club Mosses, which are biciliate and somewhat resemble those in the Bryophytes, the sperms in the Pteridophytes are spirally coiled and multiciliate, and according to the number of cilia of the sperms some writers divide the Pteridophytes into two classes, namely, biciliate and pluriciliate (Figs. 51, C; 62, F). Some of the Pteridophytes, as Selaginella (Fig. 60), are dis- tinguished by the fact that they produce two kinds of asexual spores, which are known respectively as MICROSPORES (Fig. 60, F) and MHCAS POKES (Fig. 60, E). The two kinds of spores are formed in separate sporangia, which organs may occur on the same plant or on different plants. The sporangia have the cor- responding names, microsporangia (Fig. 60, B, /) and megaspor- angia ( Fig. 60, B, g) . This differentiation in sporangia and spores also leads to a differentiation in the resulting gametophytes, the microspores giving rise to gametophytes which produce antheridia, and hence called male gametophytes ; and the megaspores to PRINCIPAL GROUPS OF PLAXTS. gametophytes which give rise to archegonia, and hence called female gametophytes. When a plant produces both micrO'Spores and megaspores it is said to be HETEROSPOROUS, as in Selaginella (Figs. 60, 62, and 63) ; while one that produces but one kind of sporangium and one kind of asexual spores is said to be ISOSPOROUS. In this connection attention should be called to the fact that the spores from a single sporangium of an isosporous plant may give rise to male and female gametophytes, which shows that a certain degree of differentiation in the spores has already taken place. The causes leading to the differentiation of the spores seem to be B FIG. 50. Male fern [Dryopteris (Aspidium or Nephrodium) Filix-mas]. A, prothallus of gametophyte as seen from the under (ventral) side showing archegonia (ar), antheridia (an), and rhizoids (rh) ; B, prothallus showing young plant (sporophyte) which has devel- oped from an oospore and is still connected with the gametophyte, roots (w), and the first leaf (b). — After Schenck. connected with nutrition, those nuclei which are in more favorable positions giving rise to larger and better nourished spores which eventually lead to the formation of the megaspores, and those which are less favorably placed leading to the microspores. The subject of heterospory is one of great interest, and when it is pointed out that all of the higher plants are heterosporous the subject has even more interest. FILICALES. General Characters. — On germination the asexual spore in the Filicales or Ferns gives rise to a thallus-like body known as 88 A TEXT-BOOK OF BOTANY. the prothallus which is frequently dorsiventral and in a number of cases somewhat heart-shaped, but varies considerably in out- line, being sometimes more or less tuberous. The prothallus is frequently but a few millimeters in diameter, and the cells usually contain chloroplasts. On the under or ventral surface rhizoids are usually present (Fig. 50, rh). The sexual organs usually arise on the lower surface (Fig. 50), but they may develop on the upper or dorsal surface or even laterally. A single prothallus gives rise to both kinds of organs, unless stunted in its growth, when it produces antheridia only. B FIG. 51. A, B, development of archegonia of a fern (Pteris) showing the neck (h), the neck-canal cells (k), and oosphere (e). — After Strasburger. C, development of antheridium in the Venus-hair fern (Adiantum Capillus-Veneris): prothallus (p), antheridium (a), sperm (s), sperm mother cell with starch grains (b) ; I, immature state of antheridium, II, sperms developed, and III, discharge of sperm mother cells and escape of coiled and pluriciliate sperms. — After Sachs. The antheridia either develop upon or are sunk in the tissues of the prothallus. The archegonia (Fig. 51) are not flask-shaped as in the Bryophytes. The venter containing the oosphere or egg- cell (Fig. 51, c) is embedded in the thallus, the structure being surmounted by a few-celled neck (Fig. 51, // ). The inner cells of the neck are known as canal cells (Fig. 51, &), and these at the time of ripening of the egg swell and exit through the opening of the archegonium, through which then the sperms enter, one of which unites with the egg, thus effecting fertilization. The fer- tilized egg or oospore takes on a cellulose membrane. PRINCIPAL GROUPS OF PLAXTS. The oospore which is held in the venter of the archegonium is not a resting spore, but germinates immediately and early differen- tiates into the several organs ( Fig. 52 ) . These arise independently and include a stem-bud (Fig. 52, s) ; a first leaf or cotyledon (Fig. 52, b) , so called because it does not arise out of the stem as the later leaves do; a first or primary root (Fig. 52, iv) ; and a foot or haustorial organ (Fig. 52, /) whereby it obtains nutri- ment from the prothallus (Fig. 52, pr). This latter organ is, how- ever, only a temporary provision, for as soon as the root grows out and penetrates the soil, it dies off and the sporophyte thus becomes independent. The stems are frequently more or less con- w A FIG. 52. The brake fern (Pier is). A, differentiation of cells in germinating oospores; B, later stage showing development of embryo: pr, prothallus; f, foot embedded in the archegonium (aw); w, root; s, young stem; b, young leaf. — A, after Kienitz Gerloff; B, after Hofmeister. densed and lie prostrate in the soil, developing roots from the under surface and leaves from the sides and upper surfaces. The leaves which constitute the conspicuous part of the ordinary ferns consist of a stalk and lamina or blade on which are borne the spor- angia (Figs. 53 to' 55). The sporangia usually occur on the under surface of the leaf in groups or clusters known as SORI (Fig. 53, A). The sori are of characteristic shape and in certain species are covered by a plate called the INDUSIUM (Fig. 53, B) which rises from the epidermis. In some species the entire leaf becomes a spore-bearing organ, and is then known as a SPORO- PHYLL (Figs. 54, 55), to distinguish it from the foliage leaves. The sporangia develop a row of cells around the margin consti- A TEXT-BOOK OF BOTAXY. tilting what is known as the AXXULUS ( Fig. 53, n) . The form of the annulus determines the manner of dehiscence of the sporangia, which occurs on drying. The spores are ejected with consider- Fic. 53. Male fern [Dryopteris (Aspidium or Xephrodium) Filix-mas]. A, portion of leaflet showing a number of more or less reniform sori near the mid-vein; B, transverse section through a ripe sori showing clusters of stalked sporangia, which are covered by the indusium (i), an outgrowth of the leaflet; C, a closed but ripe sporangium showing the annulus or ring (n), and the irregular-shaped spores within; D, showing the manner of opening of the mature sporangium and the dispersal of the spores; E, two spores much magnified. — After Dodel-Port. able force (Fig. 53, D}. They (Fig. 53, E; Fig. 57) are either bilateral or tetrahedral and require a short period to elapse before they germinate. They retain their vitality for a lon^ time, except those which are green, i.e., contain chlorophyll. The spores are PRINCIPAL GROUPS OF PLANTS. greenish or yellowish in color, variously sculptured, and vary from 0.025 mm. to 0.158 mm. in diameter. Fern Groups. — There are a number of distinct groups of FIG. 54. Several Osnftmdas. i, the royal fern (0. regalis) showing fertile tip of branch and sterile bipinnate leaflets below; 2, Clayton's fern (O. Claytoniana) showing three pairs of fertile leaflets in the middle and a number of sterile leaflets above and below; 3, cinnamon fern (O. cinnamomea) showing a fertile leaf (sporophyll) to the left and a sterile leaf (foliage leaf) to the right. ferns which vary considerably in appearance. ( i ) In the Tropics as well as in greenhouses TREE FERNS, characterized by an over- ground stem, occur. The leaves arise at the summit of the stem or trunk and form a crown. A TEXT-BOOK OF BOTANY. (2) The TRUE FERNS include by far the largest number of species which inhabit temperate regions. These vary consider- ably in size, ranging from quite diminutive plants 5 to 12 cm. high, as the slender Cliff Brake (Pellcca atropurpurea and the variety FIG. 55. Different types of Ferns and fern allies, i, fertile and sterile leaves of slender cliff brake (Pellcea Slelleri); 2, ebony spleen-wort (Asplenium platyneuron); 3, rhizome with two leaves of the common polypody (Polypodium vulgare); 4, maiden-hair spleen- wort (Asplenium trichomanes); 5, ternate grape-fern (Botrychium ternatum), showing the tripinnate sterile leaf on the left and the upright sporophyll on the right; 6, walking fern (Camptosorus rhizophyllus) showing a new plant developing from the tip of one of the leaves; 7, fertile and young sterile leaves of ostrich fern (Onoclea Struihiopteris). PRINCIPAL GROUPS OF PLANTS. 93 cristata) and maiden hair spleenwort (Asplenium Trichomanes), to plants several feet high, as in the several species of Osmunda (Fig. 54), ostrich fern (Fig. 55), etc. This group is chiefly FIG. 56. A, transverse section of stipe of Dryopteris marginalis: E, epidermis; H, hypodermis of collenchymatous cells; P, parenchyma containing starch; V, fibrovascular bundle; S, sieve; T, trachea?; N, endodermis surrounding each bundle. B, transverse sec- tion of stipe of Osmunda Claytoniana: H, hypodermis of lignified sclerenchymatous fibres; N, endodermis surrounding a large central fibrovascular bundle; Tn, tannin cells. characterized by the underground or prostrate stems, known as rhizomes, the part of the plant that is seen above ground being the leaf. 94 A TEXT-BOOK OF BOTANY. (3) There is also a group of ferns known as \YATER FERNS which are aquatic in habit ; that is, they live in marshy places or float on water. As representatives of this group may he men- tioned Marsila, from whose slender rhizome that is buried in the FIG. 57. Some fern spores. A, B, C, different views of the bilateral spores of the common polypody (Poly podium vulgare), showing outer wall (ep), middle wall (ex), inner wall (end) and line of dehiscence (dl); D, a tetrahedral spore of the royal fern (Osmunda regalis); E, F, spores of Ceratopteris thalictroides seen in two views. — :A-D, after Sadebeck; E-F, after Kny. muddy bottom of streams arise the clover-like leaves that float on the water (Fig. 59) ; and Salmnia (Fig. 58), which is a small floating plant that develops two kinds of leaves, one which float on the surface of the water and are more or less oblong-, and FIG. 58. A water fern (Salvinia natans}. A, a plant seen from side and showing floating leaves at top attached to the horizontal stem, root-like finely divided leaves beneath, and a cluster of globose sporocarps; B, a view from above showing especially the character of the upper leaves; C, young plant developing from a megaspore (msp). — A and B, after Bischoff; C, after Pringsheim. another which are filiform, branching, root-like, and submerged. The water ferns are further distinguished by the production of megaspores and microspores. (4) The ADDER'S TONGUE FAMILY, to which Ophioglossum PRINCIPAL GROUPS OF PLANTS. 95 and Botrychium belong, develops a subterranean prothallus which is destitute of chlorophyll. The prothallus is in some cases tube- FIG. 59. Marsilea quadrifolia (from Bantam Lake, Conn.), a submersed or emersed aquatic plant belonging to the Marsileaceae, a family of the Pteridophytes. Of the forty different species, only two or three are found in the United States. It produces long, slender rhizomes, which are buried in the muddy bottoms of shallow lakes or streams and from which arise the leaflets which float on the surface. The leaves are on long, slender petioles and 4-foliate, the leaflets being mostly triangular-obovate. In Marsilea quadrifolia, a European form growing in Connecticut and Massachusetts and frequently cultivated, the leaves are nearly glabrous, while in M. vestita, a form found in shallow ditches in the Southern States, the leaflets are usually hairy. This character is quite marked in the spor- ocarps of the two plants. — After a photograph by Henry Troth. 96 A TEXT-BOOK OF BOTANY. rous, and the sporophyte produces two kinds of leaves, namely, foliage leaves, and fertile leaves or those which bear the sporangia. The sporangia occur on lateral branches of the sporophyll and open at maturity by means of a horizontal slit. Ferns Used in Medicine and as Foods. — Many of the ferns contain tannin, a brownish coloring principle, and in addition an anthelmintic principle. They may also contain ethereal oils, starch, coumarin, aconitic acid, and other principles. A large number have been used in medicine, of which the following may be mentioned: Dryopteris {Aspidium or Nephrodium) marginalis and D. FilLv-mas, yielding the official Aspidium. A number of other species of Aspidiiun, as well as species of Adiantum, As- plcnium and Polypodiiun, are also used in various parts of the world. The rhizomes of some of the ferns contain considerable starch and are used to some extent as foods, as Pteris esculenta of China ; Pteridium aqniliana var. lanuginosa of the Canary Islands ; Aspidium variitui and Asplenium bulbosum of Cochin China. Polypodium vulgare contains a substance related to glycyrrhizin. Adiantum pedatum and Polypodium Phymatodes are said to con- tain coumarin, the latter plant being used in perfumery. EQUISETALES. The Horsetails, or scouring rushes (Equisetums], are peren- nial plants containing a large amount of silica in their tissues. Like in the ferns, the more or less branching, creeping rhizome persists from year to year, sending out each year new shoots. As in some of the ferns, it develops two distinct kinds of leaf-shoots, a fertile and a sterile one, each of which is distinctly jointed. The scale-like leaves are arranged in circles about the joints or nodes, the work of photosynthesis being carried on by the green stems. The fertile branch develops at the apex a group of sporophylls known as a cone or strobilns. The archesporium, or initial spore- producing zone/is unilocular. In Equisctum, the only representa- tive of the group, the spores are spherical and each is furnished with two spiral bands or elaters which assist in its dispersal. Some of the Equisetums contain aconitic acid and are used in medi- cine. Common scouring rush (Equisetiim Jiyemale) is used for PRINCIPAL GROUPS OF PLANTS. 97 polishing woods, and Equisetmn arvense is used for scouring tinware. LYCOPODIALES. The Lycopodiales, or Club Mosses (Fig. 66), are perennial moss-like plants, with more or less erect or creeping and branching stems, on which are borne numerous small simple leaves. The sporangia arise either at the base of the upper surface of the leaves or occur in terminal cones. They have short stalks, are uni- locular and 2-valved. The asexual spores are of one kind in Lycopodium and in the form of spherical tetrahedrons, resulting from the manner in which division has taken place (see Vol. II). In Selaginella (Fig. 60) two kinds of asexual spores are produced, that is, both microspores and megaspores, which in turn give rise to male and female prothalli respectively. The microspore develops a male gametophyte (Fig. 62) which remains entirely within the spore, and consists of a few-celled prothallus and a number of mother cells which produce sperms that eventually escape by the breaking of the wall. The megaspore frequently begins to develop the gametophyte (Fig. 63) while still within the sporangium. The prothallus con- sists of a number of cells and partly protrudes through the rup- tured spore wall. On the upper part of the prothallus or nutri- tive layer a few archegonia are borne. It should be stated that sometimes the archegonia are developed very early on the pro- thallus tissue, but usually they are developed after the spores have escaped from the sporangium. After fertilization of the egg a multicellular embryo develops which shows the following parts (Fig. 61) : (i) An elongated cell or row of cells which extends into the tissues of the prothallus for the purpose of obtaining nutriment; (2) a root; and (3) a stem bearing at its tip two leaves, or cotyledons. One of the specially notable characters of the plants of the Selaginella group is, as we have seen, the great reduction in size of the gametophyte, which in the case of the microspore does not enlarge beyond the wall of the spore, and in the case of the megaspore only partly protrudes beyond its wall. Isoetes. — This is a genus of aquatic or marsh plants known 7 98 A TEXT-BOOK OF BOTANY. as quillworts. The plants produce a number of filiform roots which penetrate the mud, and a compact tuft of rush-like leaves. The plants are heterosporous, as in Selaginella. The sporangia FIG. 60. Selaginella helvetica. A, sporophyte consisting of leafy branches giving rise to microsporangia (i), megasporangia (g), and rhizoids (r); B, longitudinal section of portion of branch showing a megasporangium (g) with 3 megaspores in view, a microspor- angium (i) containing microspores; C, a young microsporangium showing free mother cells before formation of tetrads; D, tetrahedral division of spore mother cell; E, ripe megaspore; F, four microspores of tetrad separated; G, microsporophyll seen from above showing ripe microsporangium. — After Dodel-Port. are borne in the axils of the leaves, the outer leaves bearing the megasporangia and the inner leaves the microsporangia. The gametophytes consist of but a few cells. \Yhile the group is het- PRINCIPAL GROUPS OF PLANTS. 99 erosporous and the gametophytes resemble those in Selaginella, the sperms are multiciliate and coiled as in the Ferns. Distribution and Uses of Lycopodiales. — A number of the Lycopodiums are common on rocks, damp woods, sandy bogs, and illustrations of several of these are shown in Fig. 66. Some tropical species are used in medicine ; the spores of Lycopodium clavatum, on account of their fixed oil, are used as a dusting powder, and for burning in the production of flash lights (see Vol. II). The Selaginellas, of which there are several native species, are commonly used for decorative purposes. Some species FIG. 61. Longitudinal section of young embryo of a Selaginella before separation from the prothallus: et, suspensor; w, root; f, foot; bl, cotyledons; lig, ligules or bud scales. — After Pfeffer. are, however, also used in medicine, and it is interesting to note that the spores of one species (Selaginella selaginoides) are used like those of Lycopodium. While the Pteridophytes do not form a very conspicuous por- tion of the flora at the present time and yield but few products of use to man, it may be pointed out that in former ages they formed the dominant vegetation of the earth. Many of the ancestral forms of this group attained the size of trees and made up the forest vegetation during the Devonian and Carboniferous Ages, the latter being sometimes spoken of as the age of Pterido- phytes. It is also called the Coal Age from the fact that the coal IOO A TEXT-BOOK OF BOTANY. measures were chiefly laid clown during this period. By some it is thought that the deposits of coal of this age were probably princi- pally formed from the remains of certain marsh plants including two extinct groups of huge, tree-like club mosses (Lepidodendron and Sigillaria) and the Calamites, representatives of the scouring rushes. SPERM OP HYTES. The Spermophytes, or Seed Plants, constitute the third of the great divisions into which plants are divided. The plants belong- c FIG. 62. Successive stages in the germination of the microspores of a Selagineila: p and w, cells of the prothallus; s, cells giving rise to sperms. A, B, D, views of spores from the side; C, view from the back; in E, the cells surrounding the sperm mother cell are dis- organized; F, two biciliate sperms. — After Belajeff. ing to this division not only form the most conspicuous feature of the flora because of their size and general distribution, but also because of the fact that they produce flowers renders a large num- ber of them especially attractive. The plants of this group are also of great importance from an economic point of view. They fur- nish a large part of the food of man and other animals, as well as materials for clothing, shelter, fuel, and divers other purposes. In this group of plants there are the highest differentiation of tis- sues and the most complicated structure. The one character which especially distinguishes them from the lower groups of plants is that of the production of seeds. PRINCIPAL GROUPS OF PLANTS. 101 The plants have for the most part well-differentiated stems and leaves, and represent the sporophyte or asexual generation. The sporophyte produces sporophylls which are of two kinds, namely, megasporophylls and microsporophylls. The megasporo- phylls bear small ellipsoidal bodies known as ovules, which develop into seeds. The megasporangium is not separate and distinct in the spermophytes as it is in Selaginella, but is embedded within an ovule and corresponds to that part of the ovule known as the nucellus. The nucellus encloses the embryo-sac, which is regarded as a megaspore (Figs. 70, 71, and 81). Each megasporangium (nucellus) therefore contains but a single megaspore, whereas in Selaginella the megasporangia contain from i to 8 megaspores. The microsporophyll bears microsporangia (pollen sacs) which contain microspores (pollen grains). The female gametophyte in the Spermophytes is still more limited in its development than even in the highest Pteridophytes (as Selaginella and Isoetes) and remains wholly within the megaspore or embryo-sac. As a result of fertilization of the egg-cell an embryo is produced which consists of root, stem, and one or more cotyledons and which with the integuments covering it constitutes the seed. Spermophytes embrace two well-defined groups, namely, ( I ) Gymnosperms, or naked-seeded plants, and (2) Angiosperms, or enclosed-seeded plants. GYMNOSPERMS. In the Gymnosperms the ovules, each of which contains a megasporangium (nucellus), are borne on an open sporophyll (carpel), and thus are exposed, as are also the seeds developed from them. In the Angiosperms the ovules are borne within closed sporophylls, and are thus protected or covered until the seeds, which develop from them, mature. The Gymnosperms represent an ancient group of plants and were more numerous during the Triassic period than now. They are mostly shrubs and trees, and do not shed their leaves period- ically as the Angiosperms do, and hence are known as k ever- greens." As in some of the Pteridophytes (Lycopodium, Eqni- setum), the sporophylls occur in groups forming cones or strobiles (Fig. 72). They not only differ in external appearance from the IO2 A TEXT-BOOK OF BOTANY. Angiosperms but also in the anatomical structure of the stem, which is without large conducting vessels. In order to understand the relation of the Gymnosperms to the Pteridophytes on the one hand and to the Angiosperms on the other, it will be necessary to consider briefly the life history of a representative group, such as the Coniferae. General Characters. — The seed consists essentially of three parts, namely, a woody or leathery seed-coat, a nutritive layer rich in oil known as the endosperm, and a straight embryo. The latter is a more or less differentiated plantlet, consisting of a stem spm FIG. 63. The female gametophyte of a Selaginella; prothallus (pr) projecting through the ruptured wall (spm) of the megaspore; ar, sterile archegonium; embi, emb-j, two embryos embedded in the tissue of the prothallus; et, et, suspensors. — After Pfeffer. with a varying number of cotyledons or first leaves (2 to 16), and a small root which is attached to a suspensor, as is the embryo in Selaginella (Fig. 63). When the embryo begins its develop- ment into the plant it uses up the nourishment with which it is surrounded in the endosperm, and as it increases in size the seed- coat is split. The root then protrudes and the cotyledons, to some of which the seed-coat is still attached, are carried upward by the stem through the surface of the soil, when the seed-coat is cast off and the plant begins an independent existence. The first root is the primary or tap root, and from this are sent out numerous branches known as secondary roots, constituting a \vell-developed PRINCIPAL GROUPS OF PLANTS. 103 root system which serves the double purpose of absorbing nutri- ment from the substratum or soil and holding or fixing the plant in its upright position. The embryonal stem grows vertically upwards, continuing its growth indefinitely. Lateral branches arise at more or less regular intervals which extend from near the ground to the apex, the younger branches continually succeeding •^Jgs - ^j-^-SSi^ Wtf* l^l^l jrWtea ,^S£ fr^N* ^wMc^^a^ / v .-*! • A-~rVSk -v -A: ,•', .»>J^S'4 i-ilr*-^ SS^TV c-^-'i -:>~w < fe.i ^^nslbiiiiSy ./^ •V ij '.-x zst&x/y r---y •— FIG. 70. Longitudinal section of an ovule of a spruce (Picea): i, integument; nc, nucellus (megasporangium) ; e, embryo-sac (megaspore) which has developed the female gametophyte consisting of endosperm (e), two archegonia (a), which show the neck (c), and the egg (n); p, germinating pollen grains (microspores) with pollen tubes (t) which have penetrated the nucellus (nc) and reached the neck cells of the archegonia. — After Schimper. of the preceding group, consisting of a venter which contains the egg, and a short neck composed of 4 to 8 cells. The male gametophyte begins to develop while the pollen is still in the sporangium. At this stage it consists of a generative cell and a wall-cell, which constitute the antheridium, the cells of the prothallus being usually suppressed (Fig. 69, D}. In addition to the extreme minuteness of the gametophytes IIG A TEXT-BOOK OF BOTANY. \vc have also to note the character of the male gamete or sperm. With the exception of the Cycads and Ginkgo, motile sperms are I"n.. -i. Development of garnet ophyte and embryo in one of the Coniferae. e, em- hryo-sac (TIHV , a. art -henonium ; h, neck of archegonium; i, integument; p, pollen lube; n, nucellus; f, wing of seed; g. fibrovascular tissue; kz, canal cells of archegonium; ka, beginning of embryo; k, nuclei; ws, tip of root; wh, root-cap; c, cotyledons; v. point of growth of stem; s, stispensor. I, early stages of embryo-sac (e) ; II, young archegonium (a) after development of neck cells (h), cell lumen (1); III, section of ovule with portion of attached seminiferous ;cale (f) showing entrance of pollen tube; IV, embryo-sac with two developed archegonia; Y. an h< ionium after fertilization, there being four nuclei at the lower part, only two of which n; VI, further development of embryo; VII, VIII, IX, X, showing develop- ment «•!' lao'e tortuous suspensor. to which is attached the young embryo (ka) ; XI, XII, mature embryo. — After Strasburger. PRINCIPAL GROUPS OF PLANTS. in not found in the Gymnosperms, but these are represented by two male nuclei which are transferred directly to the archegonium from the male gametophyte, formed through germination of the microspore (pollen grain). It may be recalled that in the Pteri- dophytes the motile sperms are discharged from the antheridium and carried by the agency of water to the archegonium, but in the Gymnosperms water is no longer a medium of trans ferral. The microspores themselves are carried to the ovules usually through the agency of wind, after which they germinate, developing a tube which carries the male nuclei directly to the archegonium without their ever having been free. The transferral of the microspores or pollen grains to the ovule is known as pollination. After pollination the wall-cell de- velops a tube, the pollen tube, and the generative cell gives rise to two male nuclei, which, with the remaining protoplasmic con- tents of the antheridium, are carried by the pollen tube to the micropyle, which it enters, penetrating the tissue of the nucellus (Fig. 70, t) . On reaching the neck of an archegonium the pollen tube pushes its way down into the venter, where it discharges one of the sperm nuclei, which unites with the egg, forming an oospore. Cessation in growth does not yet take place and the oospore develops into the embryo already described. The develop- ing embryo obtains its nourishment by means of a suspensor (Fig. 71, s), which also places the embryo in a favorable position. There being several archegonia in an ovule (Figs. 70, 71), a corresponding number of embryos may be formed, but rarely more than one survives. While the embryo is developing, the other tissues of the megaspore are likewise undergoing changes leading to the maturity of the seed. The carpels and seminifer- ous scales also continue to grow, and they usually become more or less woody, forming the characteristic cones of the pines (Fig. 72), but may coalesce and become fleshy, producing the berry-like fruits of Juniper (Fig. 75). The seed on germination gives rise to the sporophyte (tree). Groups of Gymnosperms.- -There are several important groups of Gymnosperms: (i) The Cycads or Fern Palms, which are characteristic of tropical and sub-tropical countries. The trunk does not branch as in the ordinary evergreens, and 112 A TEXT-BOOK OF BOTANY. FIG. 72. Cones ot some of the Coniferac. A, branch of Spruce Pine (Pinus echinata) with two cones; B, from Pitch Pine (Picea excelsa); C, from Great Sugar Pine (Pinus Lam- bertiana); D. from Black Spruce (Picea mariana); E, from the California Silver Fir (Abies magnified); F, from Loblolly or Frankincense Pine (Pinus Tceda); G, branch of Pitch or Torch Pine (Pinus rigida). PRINCIPAL GROUPS OF PLANTS. 113 the leaves form a crown at the summit of the stem or trunk. An important character of some of the Cycads is the production of multiciliate sperms, as in the ferns, Equisetum and Isoctcs. (2) The Ginkgonaceae (to which belongs the Ginkgo or Maidenhair Tree, which is extensively cultivated in China and Japan and is found wild in China. It is very widely cultivated in this country, owing to its ornamental foliage ; the staminate tree is preferable, as the seeds of the pistillate tree have a very offensive odor. The triangular shaped leaves occur in fascicles and the seeds are berry-like. (3) The Coni ferae is by far the most important group and consists of two families, the Taxaceae and the Pinaceae. To the Taxaceae belongs Taxus, or yew, a low tree bearing flat, linear leaves and a seed which is exposed and surrounded by the scarlet, fleshy, aril-like disk or scale. To the Pinaceae belong most of our important Gymnosperms. Pinus (Pine) is the most important genus (Figs. 67, 73, and 74). It is characterized by having needle-like leaves arranged 2 to 5 in a fascicle. The cone of the pine is usually woody, and upon becoming dry splits open so as to release the winged seeds. Perhaps the most valuable member of this genus is the white pine (Fig. 67) which is found throughout the northern half of the United States east of the Mississippi River. Its timber is light brown or reddish, soft and fine-grained, but not very strong. It is used extensively in rough building construction. Pinus palustris, or long-leaved pine, is one of the most valuable members of this group. It is the chief source of the terebinthinous products of this country, and its wood contributes no small part to the lumber industry. The long-leaved pine is tall, straight, has a thin-scaled bark and a very hard, resinous wood. The stern separates near the summit into several diverging branches, giving the tree a flattened top. The leaves are in threes, rarely in fours, from 10 to 15 inches long, and the cones are 6 to 10 inches long, the scales being armed with short recurved spines. Other pines yielding turpentine are Pinus Tccda, loblolly pine ; Pinus hetero- phylla, Cuban or swamp pine ; Pinus echinnata, short-leaved yellow pine. Tsuga canadensis (Hemlock) is a common tree of eastern North America (Fig. 73). It attains a large size, and the delicate 8 A TEXT-BOOK OF DOT A XV. FIG. 73. Leaves and cones of Balsam Fir (Abies balsamea). Larch (Larix laricina), Douglas Fir or Douglas Spruce (Pseiiiiotxit^a /<;.v;/«//<;), White Pine (Pi mis Strobtis), Hem. lock (Tsuga caun li-ti.^is), Si>rucc (Picea mariana), and Jack Pine (Pimis Banksiana). — From "^Minnesota Trees and Shrubs." PRINCIPAL GROUPS OF PLANTS. spray of its branches gives it a delicate beauty. Although its lum- ber is not very strong nor durable, it is extensively used. The bark is also used to an enormous extent in the manufacture of heavy leather. In recent years many tanneries have been built in the hemlock districts so as to be near the supply of bark. For the finer grades of leather the hemlock bark is mixed with that of "P resin 0!>a. PL \rar FIG. 74. Cross-sections of leaves of six different species of Pinus, showing in the diagrams the variation in the shapes of the cross-sections, with the distribution of the oil reservoirs, and beneath each an enlarged view of the epidermal layer and underlying tissues. — From "Minnesota Trees and Shrubs." the oak, in order to avoid the reddish color produced by the former. Another important genus is Juniperus. The red cedar (/. vir- giniana, also called Sabina virginiana) or savin is a tree producing valuable fine-grained soft and durable wood which is used exten- sively in making chests, pails, posts, etc. It is interesting to note that this tree, which is frequently planted to form windbreaks, develops the fungus Gymnosporangium in the form of cedar apples, which in the secidial stage produce the leaf rust of apple. n6 A TEXT-BOOK OF BOTAXY. The berries of the common juniper (/. coiiunitnis) are sweet and fleshy and are used medicinally as a diuretic and also in the manufacture of gin. ,. FlG. 75. A branch of Red Cedar (Junipt-rus rir^iniana) with numerous berry-like cones. PRINCIPAL GROUPS OF PLANTS. 117 Economic Uses of the Coniferas. — From an economic point of view the Coni ferae are by far the most important group of plants thus far considered. In fact, they may be ranked first in the production of valuable timber. Of those yielding timber the following species may be mentioned : White pine (Pinus Strobus) ; long-leaved, yellow, or Georgia pine (Pinus palustris Mill) ; spruce pine (Pinus echinata) ; the Redwood of Upper California (Sequoia sempervirens) ; pitch pine of New Mexico (Pinus pon- derosa) ; the Scotch fir, the common pine of Europe (Pinus sylves- tris). Some of the woods are adapted for special purposes: as that of Pinus Celubra of the high mountains of Europe and Northern Siberia, which is excellent for wood-carving ; red cedar (Juniperus virginiana) (Fig. 75) used in the making of cigar boxes and lead pencils; balsam fir (Abies balsamea) used in the manufacture of wood pulp. By reason of the oleoresinous constituents the woods of some of the Coni ferae are among the most durable known. A few years ago Jeffrey examined a specimen of Sequoia Penhalloivii which was obtained from auriferous gravels of the Miocene in the Sierra Nevada Mountains and found it to be in a very perfect state of preservation. Penhallow (loc. cit.) considers this to be the most ancient record of an uninfiltrated and unaltered wood. Coleman, in 1898, found in the Pleistocene clays of the Don Valley a specimen of red cedar (Juniperus virginiana) which not only possessed all of the external characteristics of this species but when sawed emitted the aromatic odor of the bark. In the Pleistocene deposits of the western United States and Canada are found more or less unaltered specimens of various species of Juniperus, Pseudotsuga, Picea, and Larix. Some of the pines yield edible seeds which have been used by the Indians of Western America ; as the edible or " nut pine ' of California and New Mexico (Pinus edulis) ; Pinus nwnophylla, discovered by Colonel Fremont in Northern California; Pinus Jeffreyi of Northern California ; and Pinus Pinea of Europe, the seeds of the latter being used like almonds and known as "pig- none." The seeds of Pinus Lambertiana (Fig. 72, C) of Califor- nia are baked before being used as a food. This latter species is also known as the sugar pine, as it yields a manna-like product. A TEXT-BOOK OF BOTANY. A manna is also yielded by Cedrus Libani and Lari.v decidua. The latter is known as " liriancon Manna," and contains melizitose. The bark of some species furnishes valuable tanning material, as that of the hemlock spruce (Tsitga canadensis). Thuja FlG. 76. Fruiting twig of common Juniper (Juniperus communis}, of Red Cedar or Savin (Juni penis vir^inmnn ). and young twig of White Cedar or Arbor Vitee (Thuja occiden- talis). — From "Minnesota Trees and Shrubs." The Conifene yield large quantities of volatile oils, resins, and allied products which are used both in medicine and the arts. A number of them yield turpentine (see Vol. TI). Lari.v decidua of the Alps and Carpathian mountains yields Venice turpentine. . Ibics balsamca is the source of Canada turpentine or balsam of PRINCIPAL GROUPS OF PLANTS. 119 fir; Seudotanga mucronata or Douglass Spruce (Red fir) is prob- ably the source of a balsam resembling Canada turpentine and which is known commercially as Oregon balsam. Picea Mariana or black spruce yields spruce gum, largely used in the manufacture of chewing gum, and is also the source of spruce beer. Picea excelsa or Norway spruce yields Burgundy pitch. Abies alba, white fir or silver fir yields the Strasburg turpentine. Canada pitch is the resinous exudation from the common hemlock (Tsuga canadensis) . Sandarac is yielded by Callitris quadrivalvis found growing in Northwestern Africa. Volatile oils are yielded by a number of the Coniferse, of which the following may be mentioned: funiperus Sabina yielding oil of savin; Junipcrus communis yielding oil of juniper, both of which are used in medi- FIG. 77. Microscopical view of fragments of wood found in the coal deposits of upper Silesia, Prussia. — After Link, from article by Potonie on the origin of coal and petroleum in Ber. d. d. pharm. Ges., 1907, p. 181. cine. The remains of Coniferae (Picea, etc.) are often found as fossils, as the fossil resin amber, which is used in the arts, and on distillation yields a volatile oil having medicinal properties. ANGIOSPERMS, General Characters. — They constitute the most conspicuous portion of the flora, embrace the greatest variety of forms, and are the most highly organized members of the plant kingdom. They vary in size from diminutive plants like the windflower to the giant oak which shelters it. They may accom- plish their life work in a few months, as the common stramonium, or they may persist for several hundred years, as the trees of our primitive forests. They may inhabit dry desert regions, as the Cacti and Chenopodiacese, or they may live wholly in water, as the water lilies. In short, they show the greatest adaptability I2O A TEXT-BOOK OF BOTANY. to their surroundings. But no matter how diversified they may seem in form and structure, they agree in this with possibly one exception, namely, mignonette, that the seeds are produced in a closed carpel. This has been considered, as already indicated, to be the chief difference between the Gymnosperms and Angio- sperms. • The two groups are further distinguished by several other important characters : (i) The carpel or carpels (megasporophyll) is developed into an organ commonly known as a pistil (Fig. 78). This organ consists of three parts, namely, ovary, style, and stigma, the ovary enclosing the ovules. (2) In the Angiosperms the megaspore (embryo-sac) develops a gametophyte which does FIG. 78. A, longitudinal section through orange flower (Citrus Aurantium) showing stalk (PE); sepals (s) ; petals (p); stamen with filament (F) and anther (A); compound pistil (composed of united carpels) with stigma (T), style (Y) and superior ovary (O) with ovules; disk or nectary (D). B, longitudinal section of a bud of clove (Caryophyllus) showing inferior ovary (O), style (Y), stamens (F), petals (P), sepals (S), nectary (D). not give rise to archegonia, but the egg arises directly from the megaspore nucleus by a series of divisions. (3) The Micro- sporophyll (stamen) differs considerably in structure and appear- ance from that of the Gymnosperms. The stamen may be defined as a leaf which bears sporangia (spore cases). It usually con- sists of the following differential parts : filament and anther, the latter consisting of pollen sacs (microsporangia) in which the pollen grains (microspores) are developed (Figs. 78, 79, and 80). (4) In a large number of cases in the Angiosperms there is developed in addition to the sporophylls or sporangial leaves (stamens and pistils) another series of leaves known as floral leaves (Fig. 7$). The latter usually are of two kinds, known as sepals and petals. PRINCIPAL GROUPS OF PLANTS. 121 The Development of the Two Generations, namely, the sporophyte and gametophyte, is much the same in the Angio- sperms as in the Gymnosperms ; that is, the sporophyte consti- tutes the plant body and what is commonly considered to be the plant. The gametophytes are still more reduced than was the case in the Gymnosperms, the male gametophyte consisting of but two cells. Beginning with the germination of the seed, we may outline the life history of the plant as was done under Gymnosperms. The seeds in the two groups are much alike, with the exception that in the Angiosperms they usually have two integuments. Within the Angiosperms two classes of embryos are distinguished, which give rise to the most important division of this group of plants. In the one case a single cotyledon is formed at the apex of the stem, and all plants having an embryo of this kind are known as MONOCOTYLEDONS, that is, plants having one seed leaf. In the other case two cotyledons arise laterally on the stem and opposite each other, and those plants having an embryo of this type are grouped together as DICOTYLEDONS, or plants having two seed leaves. In the monocotyledons the cotyledon is limited to one, but in the dicotyledons the seed leaves are not limited in number and there may sometimes be three or more. The sporophyte which develops from the germinating seed consists of the essential parts already given, i.e., root, stem, and leaves. The leaves are of four kinds: (i) Foliage leaves, (2) scale leaves or bud scales, (3) floral leaves, which in some cases are wanting, and (4) sporangial leaves or sporophylls. Inasmuch as the latter give rise to the gametophytes (male and female) the development of the sporangia in each will be considered in detail. The Microsporangia (pollen sacs) arise by the division of certain cells under the epidermis of the anther (Fig. 79). This process of division continues until four regions of fertile tissue (sporangia) are produced (Fig. 79, D). The sporangia are directly surrounded by a continuous layer of cells which consti- tutes the tapetum or tapetal cells (Fig. 79, t), these being in the nature of secretion cells and containing considerable oil. The tapetum is in turn surrounded by a layer of cells which are peculiarly thickened and which on drying assist in the opening 122 A TEXT-BOOK OF BOTANY. of the anther and the discharge of the pollen, and this layer is called the endothecium (Fig. 79, end). There is still a third or external layer of cells, which constitutes the exothecium (Fig. 79, ex}. These four sporangial regions may remain more or less distinct and separate at maturity, or the two on either side may con FIG. 79. Development of pollen sacs (microsporangia) in several of the Angiosperms: A, showing beginning of archesporium (a), an outer sterile layer (b), position of connective (con); B, later stage showing development of fibrovascular tissue (gf); C, longitudinal section of archesporium; D, E, F, successive later stages showing in addition pollen mother cells (sm) and tapetum layer (t). G, H, diagrammatic sections of mature pollen sacs show- ing pollen mother cells (pm), tapetum (t), endothecium (end), exothecium (ex), and in H longitudinal dehiscencc with formation of what appears to be a unilocular pollen sac on either side of the connective. — A-F, after Warming; G-H, after Baillon and Luerssen. coalesce. This latter usually occurs at maturity, when dehiscence takes place, forming apparently a single pollen sac on either side of the connective or axis (Fig. 79, //). The Microspores (pollen grains) are developed somewhat differently in Monocotyledons and Dicotyledons. In most mono- PRINCIPAL GROUPS OF PLANTS. 123 cotyledons the nucleus of each cell (pollen mother cell) making up the archesporium divides into two nuclei, each of which takes on a wall of cellulose. Each of these (daughter cells) in turn divides, giving rise to four pollen grains. In dicotyledons (Fig. 80) the nucleus of a mother cell divides into four nuclei before the walls are formed which separate the nuclei, thus giving rise to the tetrad group of spores to which attention has already been called (Fig. 60, D) under Bryophytes. The wall of each spore is divided into two layers, an inner layer consisting of cellulose known as the intine, which gives rise to the pollen tube on germi- nation of the spore; and an outer layer somewhat different in FIG. 80. Development of pollen grains (microspores) of garlic (Allium narcissi florum): a, pollen mother cell with nucleus; b, the same with homogeneous nucleus and a thicker wall; c-e, changes in nucleus prior to division; f, formation of spindle with nuclear masses in the center from which nuclear threads extend to the poles of the spindle; g, division of nuclear substance and receding of it from the center of the cell; h-i, further stages in the organization of the nuclear substance at the poles; k, formation of a wall between two daughter cells; 1, beginning of division of one daughter cell; m-n, final divisions resulting in the formation of a tetrad (group of 4 cells). — After Strasburger. composition and variously sculptured, known as the exine. When the spores are mature the original walls of the cells of the arche- sporium dissolve and the ripe pollen grains are set free, forming a yellowish powdery mass filling the pollen sac. In some cases the spores of the tetrads hang together, or even the whole mass of pollen tetrads may be more or less agglutinated, as in the orchids and milkweeds, these masses being known as pollinia. Male Gametophyte. — Before the dispersal of the pollen grains or microspores, certain changes leading to the development of the gametophyte have taken place (Fig. 81). The spore, as we have seen, is unicellular. This divides into two cells : one, which is relatively small, known as the mother cell of the antheridium (Fig. 81, v) , and another, which, composed of the remaining i24 A TEXT-BOOK OF BOTANY. nucleus with the surrounding cell-contents, constitutes the tube- or wall-cell of the antheridium. Development of Ovule and Megasporangium (nucellus). — The ovule at first develops as a small protuberance on the inner surface of the ovary, after which it differentiates into (a) a stalk or funiculus by which it is attached to the ovary, the tissue to which it is attached being called the placenta; and (b) an upper portion which becomes the ovule proper. The differentiation of the tissues is in a general way as follows : ( i ) The cells beneath the epidermis in the apical portion of the ovule go to make up the megasporangium (nucellus) ; (2) the peripheral cells from below the nucellus give rise to the integuments ; and (3) while the integu- ments are developing the archesporium or mother cell of the x. FIG. 81. Development of male gametophyte in an Angiosperm. I, pollen grain (microspore) which has divided into the mother or generative cell (v) and a larger tube-cell with nucleus (sk) ; II, appearance of pollen on treatment with osmic acid showing the separation of the generative cell (v) from the wall of the pollen grain; o.at the right giving a view of the generative cell with the nucleus embedded in the hyaline protoplasm; III, showing the development of the tube-cell into the pollen tube which contains the two male cells (nuclei) or gametes formed by the generative cell. — After Elfving. embryo-sac (megaspore) is being formed within the nucellus near the apex. Female Gametophyte.- -The archesporium divides into two cells, the lower one of which repeatedly divides, finally giving rise to the embryo-sac which is sunk in the tissues of the nucellus. The nucleus of the embryo-sac divides and redivides until 8 cells are produced (Figs. 82 and 83), which are separated into the fol- lowing groups: (i) Three of the cells form a group lying at the apex, the lower cell of the group being the egg or egg-cell, the other two cells being known as synergids or helping cells. (2) At the opposite end of the sac are three cells, known as antipodal cells, which usually develop a wall of cellulose and do not seem to have any special function. (3) Near the centre of the sac are the two remaining nuclei, which unite to form a single nucleus, from PRINCIPAL GROUPS OF PLANTS. 125 m FIG. 82. Development of embryo-sac or megaspore in an Angiosperm. la, longi- tudinal section through a young ovule. Ib, longitudinal section through a rudimentary ovule before the formation of the integument, showing mother cell of the embryo-sac (mega- spore) (em) and primary tapetal cell (t). II, later stage showing the two cells into which the mother cell has divided, the nuclei of which are in the act of dividing. Ill, mother- cell of the embryo-sac divided into four cells (sporogenous mass of cells) ; the lowest of these cells (e) displaces the rest and becomes the embryo-sac in IV. IV, pek, is the primary nucleus of the embryo-sac. V, two daughter cells resulting from the division of the nucleus of the embryo-sac. VI, VII, show egg apparatus composed of two synergids (s) and the oosphere (o), and antipodal cells (g). VIII, longitudinal section through a mature ovule with the inner integument (ii), the outer integument (ai), the nucellus (n), the vascular bundle (gf) entering the funiculus (f), and secondary nucleus in the embryo-sac (sek). — After Strasburger. 126 A TEXT-BOOK OF BOTANY. which after fertilization the endosperm is derived. The embryo- sac, as it is organized at this stage, constitutes what is regarded as the female gametophyte (Fig. 82). The undifferentiated embryo-sac constitutes the megaspore, which latter, after germina- tion or differentiation into egg-cell and other cells, constitutes the gametophyte. It is thus seen that in the female gametophyte of the Angiosperm archegonia are apparently not formed. The gametophyte, then, consists of the cell group containing the egg and the remaining portion of the embryo-sac, which latter may be compared to a prothallus. This comparison is not difficult to understand if we bear in mind the structure of the gametophyte in the Gymnosperms, and particularly if we recall the structure in Selaginella and other higher Pteridophytes. Fertilization. — \Yhile in the Gymnosperms the pollen grains are usually provided with wings so as to bring about their trans- f erral to the carpel by the agency of the wind, in the Angiosperms, on the other hand, the grains are not provided with wings, but are adapted to the transferral by insects. Pollination, however, may be also effected by the wind, as is the case with many of our forest trees. After the deposition of the pollen grain on the stigma, the tube-cell begins to form a tubular process (pollen tube) which carries the male nuclei to the egg-cell (Fig. 83, /). It pierces the tissue of the stigma (Fig. 83, h) and traverses the style (Fig. 83, g) until it reaches the micropyle of the ovule, which it enters (Fig. 83, «i), then reaching the nucellus it penetrates this, enter- ing the embryo-sac. The tip of the tube breaks and one of the generative nuclei which has been carried downward unites with the egg, after which a wall is formed, giving rise to an oospore. The oospore develops at once into the embryo or plantlet as seen in the seed, this stage being followed by a period of rest. In fact, the young plant may lie dormant in the seed for years. Development of Seed.- -The steps in the development of the mature seed occur in the following order (Fig. 84). The oospore divides into two parts, an upper portion which gives rise to the embryo, and a lower portion which by transverse segmentation gives rise to a short suspensor (Fig. 84, ?'*} which practically serves the same purpose as in the Gymnosperms (page in). The em- bryonal cell develops the embryo, which consists of: (l)a root por- PRINCIPAL GROUPS OF PLANTS. 127 tion which is connected with the suspensor (Fig. 84, w) ; (2) one or two cotyledons (Fig. 84, c) which are attached to the stem 5(3) a little bud at the apex of the stem which is known as the plumule. While the embryo is developing, the nucleus of the embryo- sac, either after fusing with the prothallial cell of the pollen grain, or in the absence of such union, begins active division, forming, FIG. 83. Diagrammatic representation of fertilization in an Angiosperm. d, floral leaves; stamen consisting of filament (c) and anthers (a,b), one of which (b) has dehisced, exhibiting numerous pollen grains; e, nectar-secreting bodies; pistil consisting of ovary (f), style (g), and stigma (h). On the latter pollen grains (i) are germinating, the tube (1) of one of them has penetrated the tissues of the stigma and style, and entered the foramen (m), or opening of the ovule. The ovule consists of several parts: raphe (n), outer integument (p), inner integument (q), chalaza (o), nucellus (s), embryo-sac or megaspore (t) with egg-cell (z), synergids (v), antipodal cells (u), and the nucleus in the center which gives rise to the endosperm. — After Sachs. a highly nutritive tissue rich in starch, oil, or proteins, known as the endosperm (see chapter on Seed). Simultaneously with the development of the endosperm the nucellus may give rise to a nutritive layer called the perisperm, or the tissues of the nucellus may be modified and form, with the altered integuments or coats of the ovule, the seed-coat. Inasmuch as the Angiosperms furnish by far the larger pro- portion of plants and plant products used in medicine, it is desir- 128 A TEXT-BOOK OF BOTANY. able to give particular attention to the morphology of this group, as also to the distinguishing characters of a number of the impor- tant families. Economic Importance. — As indicating the great usefulness to mankind of the products obtained from the Angiosperms it will be sufficient to merely mention that all of our garden vegetables as FIG. 84. Development of embryo in the shepherd's purse (Capsella Bursa-pastoris). I-VI, various stages of development: Vb, apex of the root seen from below, i, i, 2, 2, the first divisions of the apical cell of the pro-embryo (suspensor) ; h, h, cells from which the primary root and root-cap are derived; v, the pro-embryo; c, cotyledons; s, apex of the axis; w, root. — After Hanstein. well as the great crops of cereals like wheat, corn, rye, etc. ; edible fruits and seeds ; textile products, such as cotton, flax, etc. ; medic- inal products ; timbers of various kinds, as oak, mahogany, walnut, chestnut, cherry, etc., are furnished by this great group of plants. EVOLUTION. Contrary to a popular opinion, the idea of evolution is almost as old as the human race. From the time when man began to think about the things around him he could not help but see that PRINCIPAL GROUPS OF PLANTS. 129 nothing was permanent, and he could not help but wonder how both the inorganic and the organic world came to be as he found them. The fact is, then, that for years the thinking element of the human race has had a fairly clear conception of the idea of evolu- tion ; all they lacked was the proof. Nothing is more decidedly JJ4GIOSPERMS FIG. 84A. Hypothetical tree of relationship and descent of the leading groups of plants. — After Ganong. wrong than the belief that Darwin first conceived the theory of evolution. His renown only lies in the fact that he was one of the first to suggest an explanation, and probably also because his explanation came at a most opportune time and was worked up in such a masterly way. 9 130 A TEXT-BOOK OF BOTANY. The theory of evolution has as its basis the idea that the existing species of plants and animals are the descendants of earlier forms. It holds that there is an unbroken line of descent from the beginning of life on the earth, but that during the long ages the successive descendants gradually changed in appearance from their ancestors until we find the, forms of the present day. Nearly all branches of biological science give evidence in support of the theory of evolution. Embryology, for instance, has shown that in its development the individual during its life, begin- ning with the fertilization of the egg-cell, passes through a series of stages which are thought to represent the same series of stages through which the whole race before it passed. The develop- ment of the individual (i.e., ontogeny) represents in a very brief space of time the evolution of the race {i.e., phylogeny). In other words, " ontogeny epitomizes phylogeny." Another branch of science which is bringing forth new evi- dence is the branch called paleontology. This subject has to do with the study of fossil remains and with the time they existed on the earth in the living state. It has been found that fossils from the different series of formations that make up the earth's outer crust represent a regular advancement from the very simplest types to those which are most complicated, right up to the most recent forms. In not a single instance has a highly developed form been found in a layer of rocks representing an early stage in the earth's history. Every scientist of the present time, probably without exception, believes in the theory of evolution, but there is a great diversity of opinion as to how it should be explained. This diversity of thought, instead of disproving the idea of evolution, is making its truth more generally felt. The problem, then, which is confront- ing the scientist is not to prove that evolution is a truth, but to explain it ; to show how new forms may arise from old ones, — that is, to account for the origin of species. Among the many explanations the following have become most conspicuous : ENVIRONMENT. — It was naturally thought at first that the natural conditions under which organic life developed must have a certain effect upon the individual, thereby bringing about a cer- tain modification which would be transmitted in successively PRINCIPAL GROUPS OF PLANTS. 131 greater degree to those progeny living under the same conditions, and so gradually give rise to a different species. This, of course, assumes that any change induced by environment would be trans- mitted to the offspring, to be retained so long as the environment remained constant, an assumption which ds probably not far from the truth. While it is admitted that changes in the environ- ment may cause direct responses, yet it is doubtful whether they are definite or permanent enough to produce new forms. Near the end of the eighteenth century this explanation was supported by Erasmus Darwin of England, St. Hilaire of France, and Goethe of Germany. USE AND DISUSE. — There is very little difference between this explanation and the preceding one. Lamarck proposed, in the early part of the nineteenth century, that the use or disuse of organs would so modify them that the acquired differences would be inherited by the offspring. But, here again, the proof depends upon the transmission of acquired characters, and this is now almost disproved. NATURAL SELECTION. — In 1859 Darwin published his " Origin of Species by Means of Natural Selection," and this single event revolutionized science. In this book Darwin arranged an enor- mous mass of facts gained through many travels, incessant obser- vation, and prolonged experiments. He built up an argument in such a convincing way as to immediately attract the attention of the world, not only of scientists but of laymen. The theory of natural selection has for its basis the idea that great competition is continually taking place between individuals of the same species and between the individuals of various species. This struggle for existence results in the " survival of the fittest " and the destruc- tion of the unfit. The idea that two plants or animals from the same parent might vary slightly, suggested the belief that the one which was better equipped for the struggle for existence would survive and so transmit its desirable characteristics to its offspring, and that the unfortunate one would not survive and its undesirable characteristics would thus be lost to the race. The objections to the theory of natural selection are of various kinds, but the most serious is probably the fact that it is hard to conceive how a very slight difference in character can be of advan- 132 A TEXT-BOOK OF BOTANY. tage in a life and death struggle. Necessarily when natural selec- tion first begins to operate on two individuals the differences must be only slight and hardly sufficient to give one of them such a vital advantage over the other. MUTATION.- -This explanation was offered in 1901 by Hugo de Vries of Holland. The word mutation means a change. In this sense it means a sudden change and has to do with the fact that among the offspring of a certain individual may be found one or more individuals markedly differing from the parent, so much so as to be regarded in a few instances as a distinct species. Moreover, these mutants, as they are called, continue to breed true, thereby giving rise to what might very well be called a new species. In the study of mutation many experiments have been conducted by scientists and breeders. MENDEL'S LAW. — In intimate relationship with the subject of evolution is the question of heredity. In the middle of the last century there lived an Austrian monk, Mendel by name, who ex- perimented with the cultivation of peas and other plants in the monastery garden. In his studies he discovered a certain law underlying the transmission of characters in reproduction. This law, which for many years lay hidden from the scientific world, was recently brought to light and now forms the basis of most of the recent breeding experiments and is of profound value in the study of heredity. In the simplest case it is as follows: If two different species, A and B, are crossed, the result is a hybrid (AB) which combines certain characters of both parents. When this hybrid propagates, the progeny splits up into three sets : one resembling the hybrid parent (AB) ; and the other two sets re- sembling the parent forms (A and B) that entered into the hybrid. Menders law is a statement of the mathematical ratio expressed by these three groups of forms derived from a 'splitting' hybrid. This means that in a series of generations initiated by a hybrid, ap- proximately one-half of the individuals of each generation will represent the hybrid mixture, one-fourth of the individuals will represent one of the pure forms that entered into the hybrid, and the remaining fourth will represent the other pure form. Of course, the 1:2:1 ratio holds only when the one unit-character is involved, and does not apply to the hybrids as a whole, as differ- characteristics are generally inherited independently of others. PRINCIPAL GROUPS OF PLANTS. 133 It should be understood that the use of hybrids in such experi- mental work is simply a device to secure easy recognition of the contributions of each parent to the progeny. For example, if red and yellow races of corn are crossed, it is very simple to recognize the color contribution of each parent to the hybrid progeny, when it would be impossible to separate the contribution of two yellow parents. The inference is, that what is true of hybrids is true of forms produced in the ordinary way, so that laws of heredity obtained from a study of hybrids may be regarded as laws of heredity in general. In the working out of Mendel's law it has been observed that, while one-fourth of the progeny are like one parent, the remaining three-fourths will all show the characteristics of the other parent, although only one of the remaining three-fourths will breed true. That is to say that the hybrids, which make up half of the progeny, look like one of the parents, but all do not breed true to that parent. In this case the character of the true pure-strain parent which marks the hybrids is said to be a dominant character, while the character of the other pure-strain parent is said to be a recessive character, because in the hybrids its presence can not be observed and can be discovered only by breeding the hybrids. It is only by experiment and breeding that dominant and recessive characters can be determined. For instance, in the culture of peas the character of being tall has been found to be dominant over the character of being divarf. This means that all the hybrids will be tall, although one-fourth of their progeny will be dwarf. Again in the pea, the character of having a round seed is found to be dominant over that of having a wrinkled seed. In wheat the character of being beardless is dominant over that of being bearded, and again the character of being susceptible to rust is dominant over that of being immune to rust. The infinite number of characters which complicates the study of hybrids and the fact that in breeding it is sometimes the dom- inant and sometimes the recessive character which is the desirable one to maintain suggest at a glance the breadth and difficulty of the problem. CHAPTER II. CELL-CONTENTS AND FORMS OF CELLS. A TYPICAL living cell may be said to consist of a wall and a protoplast (a unit of protoplasm), although it is often customary to refer to the protoplast alone as constituting the cell. This is in view of the fact that the protoplasm which makes up the sub- stance of the protoplast is the living substance of the plant. Besides the protoplasm other substances are also found in the cell, hence in a general way the cell may be said to be composed of a wall and contents (cell-contents). The wall, as well as the cell-contents, consists of a number of substances, and, as the cell- contents are of primary importance in the development of the plant, their nature and composition will be considered first. Cell-contents. — With the distinction already made the cell- contents may be grouped into two classes : ( I ) Protoplasmic, or those in which the life-processes of the plant, or cell, are mani- fested ; and (2) non-protoplasmic, or those which are the direct or indirect products of the protoplast. The first class includes the protoplasm with its various differentiated parts, and the second, the various carbohydrates (starches and sugars), calcium oxalate, aleurone, tannin, oil, and a number of other substances. PROTOPLASMIC CELL-CONTENTS. Protoplasm. — Protoplasm occurs as a more or less semi- fluid, slimy, granular, or foam-like substance, which lies close to the walls of the cell as a relatively thin layer and surrounding a large central cavity or vacuole filled with cell-sap, or it may be distributed in the form of threads or bands forming a kind of net- work enclosing smaller vacuoles. Protoplasm consists of two comparatively well differentiated portions: (i) Certain more or less distinct bodies which appear to have particular functions and to which a great deal of study has been given, as the nucleus and plastids ; and (2) a less dense portion which may be looked upon 134 CELL-CONTENTS AND FORMS OF CELLS. 135 as the ground substance of the protoplast and which is now com- monly referred to as the CYTOPLASM (see Frontispiece). These differentiated bodies and the cytoplasm are intimately associated and interdependent. The nucleus and cytoplasm are present in all living cells, and it is through their special activities that cell j*F*';t* - fr-^:., .r --i FIG. 85. Successive stages in nuclear and cell division, n, nucleolus; c, centre-spheres s, chromosomes; sp, spindle fibers; A, B, C, division of chromosomes, i, cell with nucleus containing nucleolus (n), and two centrospheres (c) ; 2, showing separation of nucleus into distinct chromosomes (s) and the centrospheres at either pole of the nucleus; 3, forma- tion of spindle fibers (sp) ; 4, longitudinal division of chromosomes; 5, division of the cen- trospheres; 6, 7, 8, further stages in the development of the daughter nuclei; 9, formation of cell- wall whica is completed in 10 giving rise to two new cells. — After Strasburger. division takes place. When, in addition, plastids are present, con- structive metabolism takes place, whereby complex substances are formed from simpler ones. Besides the nucleus and plastids other protoplasmic structures are sometimes found embedded in the cytoplasm. These are the CENTROSPHERES (Fig. 85, c) , small spherical bodies that are 136 A TEXT-BOOK OF BOTANY. associated with the nucleus and appear to be concerned in cell division. There are, in fact, quite a number of minute bodies in the cytoplasm which may be always present or only under certain conditions, and which are grouped under the general name of MICROSOMES Or MICROSOMATA. Chemically protoplasm is an extremely complex substance, but does not appear to have a definite molecular structure of its own, being composed in large measure of proteins, a class of organic compounds which always contain nitrogen, and frequently phos- phorus and sulphur. The molecule of the proteins is large and more or less unstable, and hence subject to rapid changes and a variety of combinations, and it is to these interactions that the vital activities of the plant are attributed. Nucleus. — The nucleus consists of (i) a ground substance in which is embedded (2) a network composed of threads con- taining a granular material known as CHROMATIN, and (3) gen- erally one or more spherical bodies called NUCLEOLES, the whole being enclosed by (4) a delicate membrane (Fig. 85). The chro- matin threads are readily stained by some of the aniline dyes, and are mainly composed of nucleins (proteins) rich in phosphorus, which by some writers are supposed to be essential constituents of the nucleus and necessary to the life of the protoplast. Chroma- tin is constant in the nucleus, and prior to cell division the threads become organized into bodies of a definite number and shape known as CHROMOSOMES (Fig. 85, s). Plastids. — The plastids or chromatophores form a group of differentiated protoplasmic bodies found in the cytoplasm (Front- ispiece) and are associated with it in the building up of complex organic compounds, as starch, oil, and proteins. The term chro- matophore means color-bearer, but applies also to those plastids which may be colorless at one stage and pigmented at another. Hence we may speak of colorless chromatophores. According to the position of the cells in which these bodies occur and the functions they perform, they vary in color — three distinct kinds being recognized, (i) In the egg-cell and in the cells of roots, rhizomes, and seeds the plastids are colorless and are called LEUCO- i-LASTiDS. (2) When they occur in cells which are more or less exposed to light and produce the green pigment called chloro- CELL-CONTENTS AND FORMS OF CELLS. 137 phyll, they are known as CHLOROPLASTIDS or chloroplasts. (3) In other cases, independently of the position of the cells as to light or darkness, the plastids develop a yellowish or orange-colored principle, which may be termed chromophyll, and are known as CHROMOPLASTIDS. Chloroplastids are found in all plants except Fungi and non-chlorophyllous flowering plants, and chromoplas- tids in all plants except Fungi. Plastids vary in form from more or less spherical to polygonal or irregular-shaped bodies, and they increase in number by simple fission. They suffer decom- position much more readily than the nucleus, and are found in dried material in a more or less altered condition. Leucoplastids. — The chief function of the leucoplastids is that of building up reserve starches or those stored by the plant for food, and they may be best studied in the common potato tuber, rhizome of iris, and the overground tubers of Phaius (Fig. 2, b). The reserve starches are formed by the leucoplastids from sugar and other soluble carbohydrates. The chloroplastids occur in all the green parts of plants (see Frontispiece). They vary from 3 to n ^ in diameter and are more or less spherical or lenticular in shape, except in the Algae, where they are large and in the shape of bands or disks (Figs. 8 and 9) , and generally spoken of as chromatophores. Chlo- roplastids are found in greater abundance in the cells near the upper surface of the leaf than upon the under surface, the pro- portion being about five to one. These grains, upon close exam- ination, are found to consist of (i) a colorless stroma, or liquid, in which are embedded (2) green granules; (3) colorless gran- ules; (4) protein masses; (5) starch grains; and (6) a mem- brane which surrounds the whole. The green granules are looked upon as the photosynthetic bodies ; the colorless grains are sup- posed to assist in the storing of starch or in the production of amylase, the conditions for these processes being directly opposite, i.e., when photosynthesis is active, starch is stored, and when this process is not going on, as at night, amylase is produced and the starch is dissolved. The protein grains may be in the nature of a reserve material of the plastid and probably are also formed in connection with photosynthetic products. While the protoplasm has been termed by Huxley " The phys- 138 A TEXT-BOOK OF BOTANY. ical basis of life," the chloroplastid has been spoken of as the mill which supplies the world with its food, for it is by the process of photosynthesis that the energy of the sun is converted into vital energy, and starch and other products formed, which become not only the source of food for the plant itself, but also the source of the food-supply of the animals which feed upon plants. In other words, horse-power is derived from the energy of the sun which is stored in the starch grains of the chloroplastids. Chromoplastids. — In many cases, as in roots, like those of carrot, or flowers and fruits, which are yellowish or orange- colored, there is present a corresponding yellow pigment, and to this class of pigments the name chromophyll may be applied. Some of these pigments, as the carotin in carrot, have been iso- lated in a crystalline condition (see Frontispiece, also Fig. 86). Chromoplastids usually contain, as first pointed out by Schim- per and Meyer, protein substances in the form of crystal-like bodies ; starch-grains may also be present. The chromoplastids are very variable in shape and in other ways are markedly differ- ent from the chloroplastids. They are more unstable than the chloroplastids, and are formed in underground parts of the plant, as in roots, as well as in parts exposed to the light, as in the flower. Their formation frequently follows that of the chloroplastids, as in the ripening of certain yellow fruits, such as apples, oranges, persimmons, etc. The PLASTID PK;M I:\TS are distinguished from all other color- substances in the plant by the fact that they are insoluble in water and soluble in ether, chloroform, and similar solvents. In fact, they are but little affected by the usual chemical reagents under ordinary conditions. Apart from the difference in color, the yellow pigment (chro- mophyll) is distinguished from the green (chlorophyll) by the fact that the latter is said to contain nitrogen, and also by their difference in behavior when examined spectroscopically, chloro- phyll giving several distinct bands in the yellow and orange por- tion of the spectrum, which arc wanting in the spectrum of the yellow principle. CYTOLOC.Y, or the science of cell formation and cell life. Dur- ing recent years considerable attention has been given by botanists CELL-CONTENTS AND FORMS OF CELLS. 139 FIG. 86. Various forms of Chromoplastids: A, from the fruit of Bryonia dioica; B, the fruit of the European mountain ash (Pyrus an cup aria); C, the petals of nasturtium (Tropczolum majus); D, petals of Iris pseudacorus, E, petals of Tulipa Gesneriana; F, the root of carrot (Daucus Carola). — After Dippel in "Das Mikroskop." 140 A TEXT-BOOK OF BOTANY. to the studies of the protoplasmic structures of the cell, especially the nucleus; the reason for this being that all of the vital phe- nomena of which living organisms are capable have their origin in these substances. The nucleus is regarded as a controlling center of cell activity, for upon it all growth and development of the cell depend, and it is the agent for the transmission of specific qualities from one generation to another. Furthermore, cytolo- gists look upon the chromatin material of the nucleus as being the agent for the transmission of individual characters to offspring. The reason for this is that in the male generative cell it is prac- tically only the nucleus which fuses with the egg-cell, no other substances entering into the union. The centrosomes are usually apparent during the process of nuclear division and by some are regarded as the controlling organ of cell division, hence they are known as the dynamic centers of the cell. The functions of the plastids and cytoplasms are largely, if not entirely, connected with the synthesis, transportation, and dissociation of metabolic substances. NON-PROTOPLASMIC CELL-CONTENTS. The non-protoplasmic constituents of plants may be said to differ from the protoplasmic cell-contents in two important partic- ulars, namely, structure and function. For convenience in con- sidering them here, they may be grouped as follows : (1) Those of definite form including (a) those which are colloidal or crystalloidal, as starch and inulin ; (b) those which are crystalline, as the sugars, alkaloids, glucosides, calcium oxa- late ; (c) composite bodies, as aleurone grains, which are made up of a number of different substances. (2) Those of more or less indefinite form, including tannin, gums and mucilages, fixed and volatile oils, resins, gum-resins, oleo-resins, balsams, caoutchouc, and also silica and calcium car- bonate. I. SUBSTANCES DEFINITE IN FORM. COLLOIDAL OR CRYSTALLOIDAL. Starch is the first visible product of photosynthesis, although it is probable that simpler intermediate products are first formed. This substance is formed in the chloroplastid (see Frontispiece) and is known as ASSIMILATION STARCH. Starch grains are CELL-CONTENTS AND FORMS OF CELLS. 141 FIG. 87. Successive stages in the development of starch grains, in Pellionia Daveauana (A to N); and in the fruits of the potato plant, Solatium tuberosum (P to R). In A, two plastids with a number of small starch grains; B, a plastid in which a single starch grain is differentiated; C to L, successive stages of the development of a single grain, the plastid body being shown on the surface (p) ; M, N, the development of several 2-compound starch grains; P to R, the development of additional layers at right angles to the original grain. — After Dippel in "Das Mikroskop." usually found in the interior of the chloroplastid, but may attain such a size that they burst through the boundary wall of the plastid, which latter in the final stage of the growth of the starch grain forms a crescent-shaped disk attached to one end of the 142 A TEXT-BOOK OF BOTANY. grain, as in Pellionia. Starch is changed into soluble carbohy- drates by the aid of ferments and probably other substances, and in this form is transported to those portions of the plant requiring food. The starch in the medullary rays and in other cells of the D 0%f^?^V, 00 0 ^T\^> FIG. 88. A, potato starch grains showing the excentral and circular point of origin of growth, and lamella:; B, maranta starch grains showing fissured point of origin of growth, and distinct lunu-ll.r; (', \\hrat starch Drains showing indistinct point of origin of growth, and lamdl [•; I). corn starch grains, which are more or less polygonal in outline and have a 3- to s-angled point of origin of growth. wood and bark of plants is distinguished by being in the form of rather small rind nearly spherical grains. In rhizomes, tubers, luillis, and seeds the grains are, as a rule, quite large, and possess CELL-CONTENTS AND FORMS OF CELLS. 143 more or less distinct characteristics for the plant in which they are found. Starch of this kind is usually spoken of as RESERVE STARCH (Fig. 87). Occurrence of Starch. — Starch is found in most of the algae and many of the mosses, as well as in the ferns and higher plants. The amount of starch present in the tissues of plants varies. In the grains of rice as much as 84.41 per cent, has been found. This constituent also varies in amount according to the season of the year. Rosenberg has observed that in certain perennial plants there is an increase in the amount of starch during the winter months, whereas in other plants it decreases or may entirely disappear during this period. In the latter case, from six weeks FIG. 89. A, starch grains of Iris florentina showing peculiar horseshoe-like fissure extending from point of origin of growth; B, irregular starch grains of calumba root; C, peculiar beaked starch grains of ginger rhizome; D, starch grains of bean showing irregular longitudinal fissures; E, compound starch grains of oat. to two months in the spring are required for its re- formation, and about an equal period is consumed in the fall in effecting its solution. Structure and Composition of Starch Grains. — The formula which is generally accepted for starch is (C6H10O3)n, this being recognized by Pfeffer, Tollens, and Mylius. It is supposed that the molecule of starch is quite complex, it being composed of dif- ferent single groups of CCH10O- or multiples of the same. While this formula may be accepted in a general way, still it has been shown that there are at least two substances which enter into the composition of the starch grain, and more recent studies tend to show that it is in the nature of a sphero-crystalloid, resembling inulin in some respects. Starch grains have an interesting struc- 144 A TEXT-BOOK OF BOTANY. ture. They vary in shape from ovoid or spherical to polygonal, and have a more or less distinct marking known as the " hilum," " nucleus," or the POINT OF ORIGIN OF GROWTH. The substances of which the grains are composed are arranged in concentric layers or lamellae which are more or less characteristic and which sometimes become more distinct on the application of certain reagents (Fig. 90). The point of origin of growth and alternate lamellae are stained by the use of gentian violet and other aniline dyes, which may be taken to indicate that these layers contain a colloidal substance somewhat resembling a mucilage, while the FIG. 90. Successive stages in the swelling and disintegration of starch grains in the presence of water on the application of heat (6o°-7o° C.),or certain chemicals. Potato starch i-io; wheat starch 11-22. alternating layers are stained with dilute iodine solutions and are probably composed of soluble starch, this latter corresponding to the u-amylose of Arthur Meyer or the granulose described by Nageli. The peripheral layer of the grain appears to be a distinct membrane. It is quite elastic, more or less porous, and takes up stains readily. While starch grains usually occur singly, they are not infre- quently found in groups of two, three, or four grains, when they are spoken of as two-, three-, or four-compound. In some of the CELL-CONTENTS AND FORMS OF CELLS. 145 cereals, as rice and oat, they are loo-compound or more. The individuals in compound grains are in some cases easily separated from one another. This occurs frequently in microscopical prep- arations, and is especially noticeable in the commercial starches. The various commercial starches belong to the class of reserve starches and may be distinguished by the following characteristics : 1 I ) The shape of the grain, which may be spherical, ellipsoidal, ovoid, polygonal, or of some other characteristic form (Figs. 88 and 89). (2) The size of the grain, which varies from I to 2 /x to about loo/x in diameter. (3) The position of the point of origin of growth, which may be central (Fig. 88, C, D) or excentral (Fig. 88, A, B). In some cases there are apparently two points of origin of growth in a single grain, and it is then spoken of as " half-compound," as occa- sionally found in potato. (4) The shape of the point of origin of growth, which may be spherical, as in potato (Fig. 88, A) ; cross-shaped, as in maranta (Fig. 88, B) ; a three- or five-angled fissure or cleft, as in corn (Fig. 88, D), or indistinct or wanting, as in wheat (Fig. 88, C). (5) The convergence of the lamellae, which may be either toward the broad end of the grain, as in maranta (Fig. 88, B), or toward the narrow end, as in potato (Fig. 88, A). In most grains the lamellae are indistinct or wanting, as in wheat and corn (Fig. 88, C,D). (6) Behavior toward dilute iodine solutions, the color pro- duced varying from a deep blue in most starches to a red or yellowish-red, as in the amylodextrin grains of mace. (7) The temperature (45°-77° C.) at which the " kleister ' or paste is formed, and its consistency. (8) The appearance as viewed by polarized light, the distinct- ness of the cross, as well as the degree of color produced, varying considerably as Nichol's prism is revolved (Fig. 91). (9) Behavior toward various reagents, as chromic acid, cal- cium nitrate, chlor-zinc-iodide, diastase, and various aniline stains, showing peculiarities of both structure and composition (Fig. 90). General Properties of Starch. — If starch is triturated with 10 146 A TEXT-BOOK OF BOTANY. water and the mixture filtered, the filtrate does not give a reaction with iodine solution ; if, on the other hand, the starch is previously triturated with sand and then with water, the filtrate becomes blue FIG. 91. Larger grains of various starches as viewed through the micropolariscope when mounted in oil: A, potato (70-80 M); B, wheat (30-40 M); C, ginger (30-50 M); D, galangal (45-55 M); E, calumba (40-60 M); F. zedoary (50-75 M); G, maranta (35-50 /*); H, colchicum (10-20 M); I, corn (20-25 M); J, cassava (20-35^1 ); K, orris root (30-35 M). on the addition of iodine solution. It appears that in the latter operation the wall of the grain is broken and the soluble starch present in the grain is liberated. CELL-CONTENTS AND FORMS OF CELLS. 147 If dry starch and iodine are triturated together no color or, at the most, a faint blue color is produced; whereas, if a little water is added and the trituration repeated, a deep blue color is immediately produced. The blue color of starch solution and iodine disappears on the application of heat, but slowly returns on cooling the solution, but not with the same degree of intensity, part of the iodine being volatilized. When starch is heated with glycerin it dissolves, and if alco- hol is added to the solution, a granular precipitate is formed which is soluble in water, the solution giving a blue reaction with iodine. When starch is heated with an excess of water at 100° C. for even several weeks, dextrinization of the starch does not take place ; i.e., the solution still gives a blue color with iodine. If, how- ever, a mineral acid be added, it is quickly dextrinized, turning violet-red, reddish, and yellowish with iodine ; finally, maltose and dextrose are produced, these giving no reaction with iodine, but reducing Fehling's solution. The ferments and other chemi- cals have a similar effect on starch. When dry starch is heated at about 50° C. from 15 to 30 min- utes the lamellae and crystalloidal structure become better defined and the polarizing effects produced by the grains also become more pronounced. When starch is mounted in a fixed oil, as almond, the polarizing effects are more pronounced than when it is mounted in water, but the inner structure is not usually apparent, unless the starch has been previously heated. (For literature on the starch grain see Kraemer, Bot. Gazette, Vol. XXXIV, Nov., 1902 ; Ibid., Vol. XL, Oct., 1905 ; also Eighth In- ternational Congress of Applied Chemistry, Vol. 17, p. 31.) BOTANICAL DISTRIBUTION OF STARCH.- -This constituent is commonly present as a reserve material in a large number of plants. The sources of the commercial starches are constantly being extended. The commercial starches are chiefly obtained from one or more genera of the Graminese, Marantaceae, Eu- phorbiaceae, and Solanaceae. The following is a list of the fami- lies yielding one or more economic products which contain starch : Cycadaceae, Gramineae, Araceae, Liliaceae, Amaryllida- ceae, Iridaceae, Musaceae, Zingiberaceae, Cannaceae, Marantaceae, 148 A TEXT-BOOK OF BOTANY. Orchidaceae, Piperaceae, Fagaceae, Aristolochiaceae, Polygonaceae, Phytolaccaceae, Xymphaeaceae, Ranunculaceae, Menispermaceae, Myristicaceae, Lauraceae, Papaveraceae, Cruciferae, Rosaceae, Legu- minosae, Geraniaceae, Rutaceae, Simarubaceae, Euphorbiaceae, Celastraceae, Sapindaceae, Rhamnaceae, Malvaceae, Thymelaeaceae, Punicaceae, Myrtaceae, Umbelli ferae, Loganiacese, Apocynaceae, Convolvulaceae, Solanaceae, Scrophulariaceas, Gesneraceae, Rubia- ceae, Caprifoliaceae, Valerianaceae, and Cucurbitaceae. PERCENTAGE OF STARCH IN PLANTS. — The amount of starch in economic plants, especially those used for food, is very high, being, on an average, much greater than that of any other con- stituent except water. The percentage of starch, calculated on dry material, in a number of foods and spices is here given : Bar- ley, 53.45 to 72.90; cardamom seed, 18.66 to 40.53; carrot, 0.87 to 0.92; chestnut, 37.31 to 47.93; chinquapin, 44.45; cinnamon, 10.44 to 65.72 ; cloves, 9.41 to 51.03 ; cocoa (cacao), 3.83 to 48.73 ; corn, 36.72 to 77.54; ginger, 46.16 to 62.53; lentils, 45-37; mace, 26.77 to 56.11 ; millet, 56.70 to 74.40; nutmeg, 17.19 to 40.12 ; oak acorns, 32.64; oats, 42.64 to 63.50; onion, n.oo to 29.39; peas, 50.02 to 57.59; pepper, 28.15 to 64.92; pimenta, 16.56 to 59.28; potatoes (sweet), 8 to 78.59; potatoes (white), 25.00 to 75.00; rice, 74.80 to 84.41 ; rye, 51.15 to 74.08; wheat, 53.66 to 76.51. MANUFACTURE OF STARCH. — In the preparation of commer- cial starches the object is to break the cells and separate the starch grains, freeing the product from the other constituents of the cell as much as possible. The preparation of potato starch is exceedingly simple, as all that is necessary is to reduce the tubers to a fine pulp, the starch grains being separated from the tissues by means of a sieve. The water containing the starch is removed to tanks, the separation of the starch being facilitated by the addition of alum or sulphuric acid which coagulates the dissolved protein substances. The starch is washed and dried over porous bricks by exposure to air. It is then thoroughly dried in a hot chamber, reduced to a powder, and sifted. One hundred pounds of potatoes yield about 15 pounds of dry starch. Tt is said that diseased tubers produce as good a quality of starch as the sound tubers. In the preparation of the cereal starches the gluten interferes CELL-CONTENTS AND FORMS OF CELLS. 149 with their ready separation. The process is therefore modified by either allowing the cereals to ferment, whereby the gluten is rendered soluble and easily removed, or the flour is made into a dough which is kneaded over running water, whereby the starch grains are separated. The starch is subsequently purified by washing and settling. It is dried by gentle heat and assumes the columnar structure as seen in the more or less irregular particles in the commercial product. One hundred pounds of wheat yield from 55 to 59 pounds of starch, the fermentation process giving a larger amount. In the preparation of corn starch, a weak solution of sodium hydrate is usually employed to facilitate the separation of the starch. Sulphurous acid is also used. One hundred pounds of corn yield 50 pounds of starch. Rice starch is prepared by either an alkaline process or by an acid process similar to that used in the manufacture of corn starch, hydrochloric acid being employed instead of sulphurous acid. Rice yields a greater percentage of starch than any of the other raw materials, 100 pounds of the grain giving 70 per cent, of starch. Starch is used as a food and for various other industrial pur- poses. The principal nutritive starches are sago, tapioca, and corn. Maranta, or arrowroot starch, is largely employed in the preparation of infant foods. Much of the dextrin of commerce is prepared by the action of dilute acids upon potato starch. Starch for laundry purposes is prepared from wheat. Rice starch is largely used as a dusting-powder. Cassava starch has consider- able advantages over the other starches in the making of nitro- compounds, and is employed in the preparation of smokeless powders. PYRENOIDS. — In the chromatophores of a number of algae a distinct body is observed. It is more or less of a lenticular shape, stained a dark purple on the addition of iodine, and is known as a Pyrenoid. It is not definitely known whether it is a true cell organ having a function similar to the plastids in manufacturing starch or whether it is merely a mass of complex reserve substances. It can be differentiated readily into two distinct portions : an inner, somewhat highly refracting and 150 A TEXT-BOOK OF BOTANY. consisting of protein matter, and an outer layer, consisting of a number of starch grains. The studies of Baubier tend to show that the pyrenoid is perfectly differentiated and independent of the chromatophore, and that the starch is formed from a leuco- plastid which surrounds a phyto-globulin or crystalloid at the center. This would quite agree with the studies of Timberlake, who observed the complete conversion of the pyrenoid into starch. That the substances of the pyrenoid are in the nature of reserve food materials, is apparent from the fact that the pyrenoid entirely disappears in Hydrodictyon prior to spore formation, and that it is afterward formed anew in the young cells, thus behaving very much like a leucoplastid. Attention should also be directed to the fact that in some of the unicellular and filamentous algae the pyrenoid divides during the division of the cell, thus behaving like other protoplasmic organs. INULIN appears to be an isomer of starch and occurs in solution in the cell-sap of parenchyma cells of stems and roots, being also found in the medullary rays. It exists in greatest amounts during the early fall and spring, being changed at other times to levulose. In the Monocotyledons it is found in the Amaryllidaceae, Liliaceae, etc. In the Dicotyledons it is characteristic of the Compositae, but also occurs in the following: Asclepiadaceae, Bignoniaceae, Cactaceae, Campanulaceae, Capri foliaceae, Compositae, Cruci ferae, Droseraceae, Euphorbiaceae, Geraniaceae, Labiatae, Leguminosae, Lythraceae, Magnoliaceae, Menispermaceae, Moraceae, Nepenth- aceae, Passifloraceae, Ranunculaceae, Rubiaceae, Rutaceae, Salicaceae, Santalaceae, Theaceae, Thymelaeaceae, Urticaceae, Valerianaceae, Verbenaceae, Violaceae, etc. According to Dragendorff, there are two forms of inulin ; one of which is amorphous and easily soluble in water, and another which is crystalline and difficultly soluble in water. The latter is probably, however, a modification of the former, and it is not unlikely that the various principles known as pseudoinulin, inu- lenin, helianthenin, and synantherin arc all modifications of inulin. In examining fresh material (Fig. 92) the sections should be mounted in as little water as is necessary to enclose the section. If inulin is present it shows in the form of colorless, highly refracting globules. The latter are usually relatively small and tend to unite, forming one or more large globules. Upon increas- CELL-CONTENTS AND FORMS OF CELLS. 151 ing the amount of water they dissolve and are diffused among the other constituents. If fresh sections are mounted directly in alcohol, or if to the original aqueous mount strong alcohol is added, the inulin separates in the form of rod-like or needle-like crystals, which strongly polarize light. If the plant material is preserved for some days in 70 per cent, alcohol, the inulin separates in the form of sphere-crystals which adhere to the walls of the cell. This aggregate consists of concentric layers of radially arranged, needle-shaped crystals, the structure of which is more apparent upon the addition of either nitric acid or a solution of hydrated chloral. The crystal mass is insoluble in glycerin and sparingly soluble in cold water. It is soluble in warm water, warm solu- tions of glycerin and water, acetic acid, mineral acids, chlor- zinc-iodide, and ammoniacal solution of cupric oxide. With solu- tions of the alkalies it dissolves with a lemon yellow color, and with acetic acid the crystals dissolve, forming a greenish colored solution which soon fades. Tunmann (Ber. d. d. phann. Ges., 1910, p. 577) has sug- gested the use of a solution of pyrogallol as a distinctive re- agent for the microscopic study of inulin. The solution con- sists of o.ioo Gm. Pyrogallol, alcohol 5 c.c., and 5 c.c. of hydro- chloric acid. Upon carefully heating sections treated with this reagent the cells containing inulin are colored a violet red. A simi- lar solution made with resorcin in place of pyrogallol colors inulin a cinnabar red. In taraxacum, inula, pyrethrum, and other drugs inulin occurs in the form of an amorphous mass having a more or less angular outline. The masses are highly refracting and probably consist of aggregates of small crystals similar in appearance to those of mannit found in commercial manna. HESPERIDIN. — Although not a carbohydrate, hesperidin is of wide occurrence and separates in the form of sphero-crystals re- sembling inulin. It is a glucoside (C22H.Z6O12) , and it would appear, from the studies of Tunmann (Schweis. Woch. f. Chcm. u. Pharm., 1909, p. 794), that, like inulin, there are several forms of it. Hesperidin, like inulin, occurs in living cells in the form of a more or less viscous fluid. Upon the addition of water, alcohol, glycerin, or solutions of hydrated chloral it separates in A TEXT-BOOK OF BOTANY. the form of yellowish sphero-crystals. If the fresh plant material is placed in alcohol the crystals separate in the form of large needles, often forming branching tufts. When examined by means of the micropolariscope, they polarize light more or less strongly, depending upon how the crystals were prepared. Upon quickly drying the plant material in which it occurs, hesperidin separates in the form of irregular, slightly yellowish clumps, re- sembling those of inulin found in the composite drugs of com- merce. If the material is slowly dried, the crystals are decom- posed. Crystals of hesperidin have been found in Citrus fruits; B LJL FIG. 92. Sphere-crystals of inulin. A, parenchyma cells of the root of chicory (Cicho- rium Intybus) treated with alcohol: a, numerous small globules shortly after the addition of alcohol; b, a somewhat later stage, showing the fusion of many of the small globules of inulin; c, crystal formation in the globules after the alcohol has acted upon the cells for 24 hours. B, sphero-crystals resembling starch grains formed in the tubers of Dahlia vari- abilis in alcoholic material: in b, the section has been treated with nitric acid, the crystal aggregate showing a trichiten structure. — After Dippel in "Das Mikroskop." the fruit of Coccuhts laurifolius; the leaves of Buchu, and Pilo- carpus ; species of Mentha, Hyssopus, Teucrium, Satureia, Tilia ; Cojiiitui- uKiculatitni ; Scrophularia nodosa, and stamen hairs of the flowers oi Verbascum. The crystals are found especially in the epidermal cells of bracts. The crystals in the hairs of the flowers of Verbascum are usually referred to as a sugar, but, according to the studies of Tunmann, are in the nature of a hesperidin. CELL-CONTENTS AND FORMS OF CELLS. 153 If sections are mounted in a small quantity of water and the latter replaced with dilute glycerin, followed by concentrated glycerin, then there separates in the cells a number of yellowish globules which are highly refractive (Fig. 93) ; these globules tend to unite in the center and very soon crystallize. The sphero- PIG. 93. Hesperidin. A, B, formation of sphero-crystals in the epidermal cells of the foliage leaves of Linden upon the addition of glycerin; in A the hesperidin occurs in highly refracting globules, which in B have united in a large central globule in which a crystal- aggregate has formed. C, crystals in stamen hair of the flower-bud of Verbascum. D, crystals in the cells of the upper epidermis of Hyssopus officinalis. E, cells of the upper epidermis of the foliage leaves of the Linden. — After Tunmann. crystal consists of radiating needles, the aggregate frequently being marked by concentric lamellae, the whole being surrounded by a more or less mucilaginous wall (Fig. 93). As there are other substances in the cell the sphero-aggregate may contain some of these in the interstices. If the crystals are formed slowly and in the cold they are apt to be of a yellowish, or even dark yellow, color, whereas if heat is employed and the crystallization 154 A TEXT-BOOK OF BOTANY. is more rapid they are nearly colorless and dissolve readily. The crystals of hesperidin are insoluble in water, alcohol, glycerin, ether, chloroform, solutions of hydrated chloral, dilute sulphuric acid and dilute or concentrated hydrochloric acid and nitric acid. They are sparingly soluble in ammonia water and hot acetic acid. Upon the addition of either dilute or concentrated solutions of potassium hydroxide or sodium hydroxide, hesperidin dissolves, forming a yellowish solution. With concentrated sulphuric acid it gives a deep yellowish solution, \vhich upon warming becomes a reddish-brown. Sometimes hesperidin, as in the stamen hairs of Verbascum, is colored with concentrated sulphuric acid only a light yellow. GLYCOGEN is a carbohydrate allied to amylo-dextrin and occurs commonly as a reserve food material in the fungi and some of the Cyanophycecc. It usually occurs in the form of a more or less amorphous mass in the hyph;e of the fungi, but occasionally is found in definite granules resembling starch. It is supposed to arise in plastid bodies resembling leucoplastids, but its general formation is controlled by the protoplasm. In yeast it is found in large quantities, sometimes nearly filling the entire cell. CRYSTALLINE SUBSTANCES. The sugars constitute a group of crystalline principles of wide distribution. They occur in the cell-sap, from which by evaporation or on treatment with alcohol they may be crystallized out. There are chemically two main groups : monosaccharoses (formerly termed glucoses) and disaccharoses (formerly the saccharoses). Under the former are included the simple sugars containing two or more atoms of carbon and known as biose (C2H4O2), etc. Among the pentoses (QH10O5) are rhamnose, a component of certain glucosides ; fucose, found in fucus and other brown algae, and chinovite, occurring in certain Cinchona barks. The most important subdivision of the monosaccharoses comprises the hexoses (CoH^O,.), which include glucose and fructose, and are widely distributed ; d-mannose, found in the manna of Fra.vimis Omits and obtained by hydrolyzing cellulose, especially the reserve cellulose in the seeds of the vegetable ivory. Of the disaccharoses (C^Il,,* ),, ) cane-sugar is the most im- CELL-CONTENTS AND FORMS OF CELLS. 155 portant. In this group are also included maltose, formed by the action of diastase on starch and by the action of ferments on glycogen ; trehalose or mycose, found in the Oriental Trehala, ergot, Boletus ediilis, and other fungi ; melibiose, occurring in Australian manna and in the molasses of sugar manufacture; touranose, found in Venetian turpentine ( obtained from Larix europcca) and in Persian manna ; and agavose, occurring in the stalks of Agave americana. Of the numerous sugars the following are likely to be met with in the microscopical study of drugs and economic products : Dextrose (grape-sugar or dextro-glucose) is found in sweet fruits, the nectaries of the flowers, and stems and leaves of various plants. It crystallizes in needles and varies in amount from I to 2 per cent, (in peaches), to 30 per cent, in certain varieties of grapes. It also occurs in combination with other principles, form- ing the glucosides. Levulose (fructose, fruit-sugar, or levo-glucose) is associated with dextrose, occurring in some instanc-es even in larger quanti- ties than the latter. Sucrose (saccharose or cane-sugar ) is found rather widely distributed, as in the stems of corn, sorghum and the sugar-cane; in roots, as the sugar-beet ; in the sap of certain trees, as sugar- maple and some of the palms; in the nectaries and sap of certain flowers, as fuchsia, caryophyllus, and some of the Cactacese ; in seeds, as almond and chestnut, and in various fruits, as figs, mel- ons, apples, cherries. In some plants, as in sugar-cane, the yield is as high as 20 per cent. It crystallizes in monoclinic prisms or pyramids, and forms insoluble compounds with calcium and strontium. Maltose is found in the germinating grains of cereals (see Malt) ; it forms colorless, needle-shaped crystals resembling those of dextrose, and forms compounds with calcium, strontium, barium and acetic acid. Trehalose occurs in some fungi, as ergot and Amanita )inis- caria — the latter containing as much as 10 per cent, in the dried plant. Mannitol occurs in the form of needles or prisms and is found in the manna of Fraxinus Ornus to the extent of 90 per cent. It A TEXT-BOOK OF BOTANY. is also found in some of the Umbellifene, as Apium graveolens, some of the Fungi and sea-weeds, and is rather widely distributed (Fig. 94). Dulcitol, which is closely related to mannitol, is found in Euonymus europccus and in most of the plants of the Scroph- ulariaceae. PERCENTAGE OF SUGAR IN PLANTS. — No analysis is necessary to indicate that most fruits contain quite a large percentage of sugar. The following figures show the amount of sugar in some of the more common fruits, the per cent, being calculated on FIG. 94. Orthorhombic crystals of Mannitol (Mannit) obtained from aqueous solutions: A, large crystals; B, feathery aggregates of needles. dry material: Apple, 33.16 to 87.73; apricot, 7.58 to 86.21; banana, 6.20 to 21.90; blackberry, 32.67 to 40.17; cantaloupe, 0.27 to 11.98; cherry, 29.97 to 85.86; currant, 33.76 to 75.49; fig, 10.00 to 29.90; gooseberry, 47.33 to 79.82; grape, including raisin, 67.82 to 83.00; huckleberry, 12.60 to 46.87; orange, 36.48 to 66.91 ; peach, 6.69 to 74.07; plum, 15.25 to 78.70; prune, 32.04 to 69.46; pumpkin, 0.15 to 11.98; and raspberry, 14.93 to 47.50. The following percentage of sugars is present in some of the cereals, common vegetables, etc. : Asparagus, 0.45 to 3.47 ; barley, 5.82 to 8.73; beet (garden), 4.20 to 31.45; beet (sugar), 3.55 to 89.61 ; buckwheat, 1.42 to 1.67; carrot, 3.62 to 15.30; cauliflower, 1.22 to 7.40; chestnut, 5.22 to 8.52; cocoa (cacao), 2.77; coffee, 0.20 to 14.50; corn, 0.96 to 6.77; cucumber, 0.72 to 1.51; CELL-CONTENTS AND FORMS OF CELLS. 157 lentils, 2.75; maple sap, 2 to 4; oats, 0.51 to 5.27; onions, 0.44 to 14.02; rye, 0.39 to 9.46; sorghum juice, 8.60 to 14.70; sugar- cane juice, i6.ooto 18.10; spinach, 0.06 to 6.66 ; turnip (Swedish), 5.05 to 9.67; sw€et potato, 0.32 to 8.42; tomato, 2.53 to 3.86; vanilla, 7.07 to 9.10; wheat, 0.58 to 5.12. HONEY-DEW is a pathological sugar formed as a result of the stings of insects (Aphides and Coccideae) on the leaves of certain trees. There are a number of trees the leaves of which, during the summer time, are covered with a thin layer of sugar solution. Among these may be mentioned the linden, tulip poplar, and chestnut. Honey-dew may also be formed, according to Bonnier, without the assistance of aphides, and may be seen oozing out of the stomata. It may be formed in such quantities that it may drip from trees, as in the so-called rain trees of the Tropics (see Pfeffer, <; Physiology of Plants "). THE ORIGIN AND FORMATION OF CARBOHYDRATES. — The first visible product of photosynthesis is starch, and this is sometimes called photosynthetic starch. Investigations during recent years seem to indicate that grape-sugar or dextrose is the basal photo- synthate, and that from this starch is later formed in the plastid. This sugar is called photosynthetic grape-sugar to distinguish it from the grape-sugar found in the cell-sap of the grape, raisins, figs, etc. There is no question but that in the plastids starch is readily formed from glucose, and, vice versa, that the starch in the plastids is readily changed through the agency of the ferment, amylase, into grape-sugar. There are four factors necessary for the formation of a photo- synthetic carbohydrate (starch or glucose) by the chloroplastids : ( I ) Light ; and in this condition it is the energy of the red and blue rays of sunlight which are necessary to bring about the synthesis. (2) Carbon dioxide. This compound must be present in about the normal proportions that we find it in the air, namely, 3 parts in 10,000. (3) Water is essential, and this is always pres- ent in living cells. It is by the dissociation of the CCX and H.2O and rearrangement of the atoms that carbohydrates are formed, being either starch (CCH10O5) or glucose (C6H12O6), with oxy- gen as a 'by-product. These interactions may be shown by the following equations : 158 A TEXT-BOOK OF BOTANY. 6C02 + 5H20 = C6H1005 + 6O2. (Starch) 6CO2 + 6H2O = C6H12O6 + 6O2. (Glucose) (4) Certain mineral substances must be present, although, appar- ently, they take no part in the photosynthetic reaction. Bokorny has shown that compounds of potassium are essential to bring about the reactions above given. Some form of iron has always been considered necessary for the development of the green pigment or chlorophyll in the chloro- plastid. While this element may seem to be necessary in water culture, it is not always essential, particularly if plants are grown under control conditions in sand. The development of chlorophyll also requires the presence of oxygen. The activity of the chloro- phyll apparatus is further influenced by other factors, viz., the maintenance of a proper temperature. It is self-evident that there is a minimum and maximum temperature at which photosynthesis is scarcely perceptible, and that there is an optimum temperature during which the activity of the chloroplastid is at its height. The latter varies with different plants, depending on the climate to which they are either indigenous or naturalized. In the Tropics the optimum temperature is somewhat higher, while in the Arctic regions it is much lower. In temperate climates the optimum varies between 20° C (68° F.) to 30° C. (86° F.). From the facts just given it would appear that considerable is known in regard to the conditions and the substances which are concerned in the formation of photosynthetic products. On the other hand, we know practically nothing of the successive steps in the formation of either starch or glucose in the plant. Numerous experiments have been conducted and a number of hypotheses have been advanced. According to von Baeyer, the first step in the process of photosynthesis is a reduction in the CO2, formalde- hyde being formed, and this is then polymerized into a carbohy- drate, which is finally changed into dextrose. This may be repre- sented by the following equations : CO2 + HaO— >-HCHO + O2 xHCHO=(CH2O)x 6(CH2O)=C6H12O6 CELL-CONTENTS AND FORMS OF CELLS. 159 There are a number of other views which have been advanced. Erlenmeyer, for instance, has suggested that instead of formalde- hyde being first formed, formic acid is the first product of photo- synthesis, hydrogen peroxide being liberated ; both of these then are decomposed, formaldehyde being formed according to the following equations : CO2 + H2O = HCOOH + H2O2 HCOOH + H2O2 = HCOH + H2O + O2 By the further condensation of formaldehyde as in the hy- pothesis of von Baeyer, dextrose is formed. On the other hand, Brown and Morris consider that the first carbohydrate formed is, in reality, cane-sugar, and that from this, then, dextrose and the other carbohydrates are formed. Some very interesting experiments were conducted by Berthe- lot (Conipt. rend., 1898, 1900, etc.), who obtained both formic acid and formaldehyde while working with a mixture of carbon dioxide and hydrogen. Later he obtained a synthetic carbohy- drate, which on warming had an odor of caramel. Furthermore, when using an excess of carbon monoxide with hydrogen, Berthe- lot obtained a substance closely related to oxy-cellulose. Lob (Ber. d. d. phann. Ges., 1907, p. 117) concludes that from formal- dehyde, glycolic-aldehyde (xCHO.CH2OH) is formed; this is then followed by the formation of gly eerie-aldehyde (CH2OH.CH- OH.COH), which is finally polymerized into a hexose as glucose, or even a higher carbohydrate. THE ALKALOIDS include a group of organic bases which possess remarkable toxicological properties. They are compounds of car- bon, hydrogen, and nitrogen ; oxygen is also usually present, except in the liquid or volatile alkaloids, in Which it is wanting. They are usually combined with some organic acid, as malic acid or tannic acid. In many cases the alkaloids are combined with acids that are peculiar to the genus, — e.g., aconitic acid in Aconitum, meconic acid in Papaver, etc. They are found in a large number of plants, especially among the Dicotyledons, and are rather char- acteristic for certain families, as those of the genera Strychnos, Cinchona, Erythroxylon, Papaver, etc. When present, alkaloids may be found in any part of the plant, but usually they are most abundant in certain definite regions, as roots, rhizomes, fruits, 160 A TEXT-BOOK OF BOTANY. seeds, or leaves. Furthermore, the amount is greatest at certain stages of development, as in the fully ripe seeds, more or less immature fruits, during the resting periods of roots and rhizomes, and in leaves when photosynthetic processes are most active. They occur in greatest amount in those cells which are in a poten- tial rather than an active condition, being associated with starch, fixed oils, aleurone grains, and other reserve products in the roots, rhizomes, and seeds. They are found in fruits in greatest amount during the development of the seed, but after the maturing of the latter they slowly disappear, as in the opium poppy and conium. The alkaloids probably arise in the protoplasm, although they may also be formed from the decomposition of protein substances. The fact that asparagine, a weak base, is usually present when the proteins are being formed from the protoplasmic substances and is also present when the proteins are being used in the growth of the plant, as during the germination of seed, would seem to indicate that both views are more or less tenable. The studies of Lotsy on Cinchona showed that alkaloids are formed in con- nection with photosynthetic processes and that they are subse- quently stored for the use of the plant. On the other hand, it is rather interesting to note that when cinchona trees are grown in the hot-house they do not produce any quinine, and, again, it is said that the conium growing in Scotland does not contain any coniine. From these observations we must conclude that alkaloids are produced only under certain conditions, and that they are not essential metabolic substances. The fact that the presence of alkaloids may be demonstrated in the thick- walled cells of the endosperm in ilux vomica has led some investigators to conclude that they may arise in the cell-wall. The occurrence of alkaloids at this point is due to their imbibition by the wall, just as other soluble cell contents are absorbed, especially upon the death of the cell. MICROCHEMISTRY OF AL K Ai.oiDS.- -The alkaloids occur in rather large quantities in a number of plants. Seldom do we find them in the form of crystals in the plant cell. Crystals of the alkaloid Piperine are not infrequently observed in the oil secre- tion cells of the endosperm of Piper niyrum (Fig. 94, A}. The CELL-CONTENTS AND FORMS OF CELLS. 161 alkaloids form crystallizable salts and, in many instances, definite double compounds. Nevertheless, not a great amount of progress has been made in their detection and localization, either in the living plant or in economic products. The reason for this is that other substances, as calcium oxalate, may interfere with the reactions forming crystals with the reagents, so that nothing definite can be deduced. Then again, when an alkaloid is charac- terized by certain color reactions, especially if a rose or violet color is formed, it may be due to the reaction of the reagent with carbohydrates or protein substance. For this reason practically FIG. 94 A. Crystals of Piperine: A, cells of endosperm showing a single oil cell (b) in which crystals of piperine have separated; (a) starch bearing parenchyma. B, piperine crystals separated from sections which have been first treated with alcohol, and to the oily globules remaining after evaporating the alcohol, a drop of distilled water has been added. In. from fifteen to thirty minutes there separate needles, short rods and aggregates of piperine. — After Molisch's work on Histochemie. there are only a few instances where satisfactory results are obtained in the study of alkaloids in plant tissues. These, for the most part, have been obtained in connection with the dried mate- rials of commerce. As it is very important that these studies should be carried further, a few illustrations may be given. Hydrastis contains two alkaloids in considerable quantities which form definite salts with nitric and sulphuric acids. Fur- thermore, this plant does not contain calcium oxalate, so that the crystals formed upon the addition of mineral acids could not be of either the nitrate or sulphate of calcium, and if in other respects they corresponded to the sulphates and nitrates of the alkaloids peculiar to hydrastis, then the crystals must be salts of the alka- loids. If sections of the fresh rhizome o M£-..//K> '-Q FIG. in. Phyto-globulins: A, cell of tuber of white potato (Solanum tiibernsum) showing protein cyrstals (k), starch grains (st), nucleus (n); B, aleurone grains of the seed of the castor-oil plant (Ricinus communis); C, aleurone grains of fruit of fennel (Facnic- ulum vulgare) containing large calcium oxalate crystals (Ca) which are strongly polarizing, as shown in the isolated grains; D, aleurone grains of Brazil-nut (Bertholletia excelsa); g, globoids; k, protein crystals. proteins, which are compounds containing both nucleic acid and protein. (3) Derived Proteins, or compounds resulting from the action of enzymes or acids upon proteins. I. Most of the investigations up until now have been con- ducted on the Globulins, which are distinguished by being insoluble in water but soluble in saline solutions. A number of them readily crystallize, and these can be generally obtained by diluting their CELL-CONTENTS AND FORMS OF CELLS. 195 sodium chloride solutions with water heated from 50° to 60° until a slight turbidity forms. Warm the diluted solution until the tur- bidity disappears and then allow it to cool slowly, when well- defined crystals of the protein separate (Fig. 112). Crystals of the globulin (so-called excelsin) of Brazil-nut were obtained by Osborne by simply dialyzing the faintly acid saline solution in running water. Many of the globulins have received distinctive names, as Amandin, found in the almond, peach, plum, and apri- cot ; Avenalin, found in oats ; Castanin, found in European chest- nut ; Conglutin, found in lupines ; Corylin, found in hazel-nut ; Edestin, found in hemp-seed ; Excelsin, found in Brazil-nut ; Glycinin, found in soy-bean ; Juglansin, found in European wal- nut, American black walnut, and butter-nut ; Legumin, found in peas and lentils ; Maysin, found in Indian corn or maize ; Phaseolin, found in kidney and lima beans ; Tuberin, found in the potato ; Vicilin, found in peas, horse-bean, and lentils ; and Vignin, found in cow-pea. Globulins have also been isolated from the seeds of other plants, but to these distinctive names have not yet been given. Among these may be mentioned barley, cocoanut, castor- bean, cotton-seed, flaxseed, mustard-seed, peanut, radish-seed, rape-seed, rye, sesame-seed, sunflower-seed, and squash-seed. II. ALBUMINS are distinguished from globulins by the fact that they coagulate on the application of heat ; they are also solu- ble in water, showing neutral or but a slightly acid reaction. Most seeds and probably most plant juices yield proteins which are as well entitled to be placed in the group of albumins as any of those of animal origin. The best characterized vegetable albumins are Legumelin, found in lentils, cow-peas, peas, and soy-beans ; Leucosin, found in barley, rye, and wheat ; Phaselin, found in kidney-bean ; and Ricin, found in castor-bean. III. Another well-defined class of Proteins are known as GLUTELINS, which are characterized by being insoluble in neutral aqueous solutions, saline solutions, and alcohol. The glutenin of wheat is the best representative of this group. IV. The alcohol-soluble proteins, known as Prolamins, have been found in corn, oats, sorghum, and wheat. It has recently been proposed to bring this group of proteins in a group by themselves and call them k gliadins," but as this name has been used to 196 A TEXT-BOOK OF BOTANY. designate a definite protein obtained from wheat, a more distinctive name has been proposed by Osborne, who calls this group " pro- lamins," because all its members which have thus far been hvdrol- * yzed yield a relatively large quantity of both proline and amide nitrogen. The prolamins are characterized by their solubility in alcohol from 70 to 90 per cent. They are nearly or wholly insoluble in water, but their salts are freely soluble in solutions of acids or alkalies. (See The Vegetable Proteins," by Thomas B. Osborne.) GLUTEN is a mixture of proteins occurring in wheat. It con- sists of about 4 per cent, of gliadin (prolamin) and 4 per cent, of glutenin (glutelin). On an average 100 pounds of flour will yield 8 pounds of gluten. The " hard " wheats contain more gluten than the "soft' varieties. The gluten of wheat is said to possess a higher dietetic value than the gluten of corn or rye. Crude gluten may be prepared by making a dough with 30 Gm. of flour and about 15 c.c. of water. This is allowed to stand for an hour and the starch washed out by krreading it between the fingers under a gentle stream of tap water. The resultant product is of a grayish color, sticky, tough, and elastic, and when pure is capable of being drawn out into long bands or shreds. The strength of a flour, — i.e., its capacity for making a porous and spongy loaf, — de- pends mainly on the quality and quantity of gluten it contains. In the preparation of ordinary flour much of the layer containing gluten is separated with the coats of the grain in the course of bolting. Graham flour, on the other hand, being unbolted, has practically the same constituents as the wheat grain itself. The name " gluten flour ' is applied to one in which the greater part of the starch is removed. Gluten flours are used by diabetic j patients and have a high nutritive value when scientifically pre- pared. TOXALBUMINS OR Toxic PROTEINS. — Proteins which are ex- ceedingly toxic have been isolated from several plants. That the protein substances possess poisonous properties has sometimes been questioned, but there seems to be no doubt but that true toxalbumins occur not only in seeds, but in other parts of the plant. The following of these principles have been rather care- fully studied: Ricin, found in the seeds of Riciuus communis ; CELL-CONTENTS AND FORMS OF CELLS. 197 FIG. 112. Phyto-globulins (crystaloids) from several sources: A, a, b, from the white potato; B, a to f, from the seeds of castor oil plant (Ricinus communis); in b and b are shown different views of the same crystal; C, a to f, from the seeds of the Brazil hut (Bertholletia excelsa). — After Dippel in "Das Mikroskop." 198 A TEXT-BOOK OF BOTANY. Abrin, occurring in the seeds of Abrus precatorius; Curcin, in the seeds of Jatropha Curcas; Crotin, in the seeds of Croton Eluteria; and Robin, in the bark of Robinia Pseud-acacia. The pollen of rye is also said to contain a toxalbumin, which, when adminis- tered in extremely small doses, accentuates the symptoms of hay fever in patients afflicted with this disease. Under the name of " Vegetable Agglutinins ' have been brought those protein sub- stances which when added to a suspension of blood-corpuscles rap- idly cause them to agglutinate. Those substances that possess the same properties but are not poisonous are known as " Phasins." (Consult "The Vegetable Proteins," by Osborne; and " Beitrage zur Kenntnis der vegetabilischen Hamagglutinine," by R. Robert.) ORIGIN AND FORMATION OF PLANT PROTEINS. — It has been shown that carbohydrates originate in chloroplastids and are formed under the influence of sunlight from two simple substances, viz., carbon dioxide and water. Protein substances, on the other hand, are not formed in any definite organ, but arise in the proto- plasmic contents of the cell. This function is not limited to the protoplasm of green plants, as fungi also possess this property. Furthermore, proteins may be formed in organs growing in the dark as well as those exposed to the light. Proteins arise through the interaction of nitrates, sulphates, and compounds of ammonia with either formaldehyde or some simple carbohydrate. It is supposed that the nitrates and sulphates are decomposed by plant acids, furnishing the necessary nitrogen and sulphur. Treub, by reason of his studies on Panghtm ednlc, has advanced the theory that in the construction of protein compounds the nitrogen is supplied by hydrocyanic acid. Apart from the facts just men- tioned, all theories with regard to the formation of proteins are mere speculations. We are indebted to Emil Fischer and his students (" Unter- suchungen iiber Aminosauren Polypeptide und Proteine," Berlin, 1906) for much information concerning the structure of proteins. They have prepared synthetically several protein-like substances, although no natural occurring protein has as yet been obtained. From these studies it has been shown that proteins belong to a CELL-CONTENTS AND FORMS OF CELLS. 199 class of chemical substances designated as " polypeptides ' which are formed by the condensation of several amino acids. THE PERCENTAGE OF PROTEIN IN PLANTS.- -The amount of protein in plants varies considerably. It is found in greatest amounts in seeds, especially in the seeds of the Leguminosae and the grains of cereals. It is also found in surprisingly large quanti- ties in a number of the vegetables. Were it not for the fact that the fungi contain large quantities of water, they would be considered the most nutritious of all vegetable foods, as they contain in dry substances over 50 per cent, of protein. As the fresh mushrooms, however, contain nearly 90 per cent, of water, this brings the pro- tein content to but about 5 per cent. The percentage of protein in dried material from a number of sources may be of interest, as follows: Grains or Cereals. — Barley, 7.64 to 17.90; buckwheat, 9.75 to 17.25; corn, 6.41 to 17.02; oats, 8.35 to 21.88; rye, 8.39 to 17.38; rice, 6.49 to 12.81 ; and wheat, 8.30 to 27.88. Leguminous Seeds. — Kidney beans, 22.53 to 36.46; lentils, 14.58 to 34.34; lima beans, 15.94 to 25.63; Lupinus luteus, 15.62 to 61.27; peanut, 25.39 to 33-73 5 Peas> 2I-59 to 32.94; soja beans, 24.38 to 49.10; string beans, 13.06 to> 20.19 ; and Vicia faba, 21.00 to 36.10. Miscellaneous Seeds. — Beechnut, about 25 ; cacao, 7.32 to 15.94; cocoanut, 7.75 to 10.90; chestnut, 5.15 to 15.75; hazel-nut, 16.23 to 21.22; flaxseed, 18.49 to 33-So; mustard, 15.50 to 39.66; coffee, 17.11 to 25.09; rape-seed, 15.18 to 28.13; ricinus, 16.35 to 22.28; sunflower-seed, 5.67 to 33.89 ; sweet almond, 17.50 to 26.62. Common Vegetables. — Asparagus, 15.12 to 33.52; sugar beets, 3.11 to 23.02; garden beets, 4.19 to 29.27; carrots, 3.79 to 16.64; cauliflower, 17.23 to 37.75 ; celery, 8.44 to 25.19 ; cucumber, 21.38 to 26.06; garlic, 1.17 to 13.50; parsnips, 6.38 to 13.50; potatoes, 2.21 to 17.59; sweet potatoes, 1.70 to 19.61; radish, 13.00 to 22.13; spinach, 27.50 to 45.33; and turnips, 4.01 to 21.00. Fruits. — Apples, 0.22 to 1.32; apricots, 0.13 to 1.79; bananas, 3.37 to 7.75; cherries, 0.97 to 4.75; cucumber, 21.38 to 26.06; currants, o.n to 1.44; figs, 0.90 to 2.58; gooseberries, .21 to .94; grapes, 0.22 to 1.20; lemons, 0.49 to 2.90; musk melon, 4.69 to 22.23; oranges, 4.83 to 2.24; peaches, 0.23 to 1.67; pears, 0.19 to 200 A TEXT-BOOK OF BOTANY. 0.56; plums, 0.27 to 0.99 ; prunes, 0.59 to 0.69; pumpkin, 30.31 to 36.25; raspberries, o.iS to 147; strawberries, 0.35 to 1.05. Spices. — Anise, 16.31 to 18.15; capsicum, 11.20 to 16.81 ; cardamom, 5.50 to 14.77; caraway, 19.43 to 20.25; cloves, 4.73 to 7.06; cinnamon, i.oi to 8.00; coriander, 10.94 to 12.03; curcuma, 9.18 to 12.56; dill, 6.75 to 21.56; fennel, 16.28 to 17.19; ginger, 3.27 to 10.83 ; mace, 4.55 to 7.80 ; mustard, 15.50 to 39.66; nutmeg, 5.16 to 7.12 ; pepper, 15.18 ; paprika, 10.9 to 27.16. Miscellaneous. — Agaricus campestris, 20.63 to 62.94; sea- weeds, 5.56 to 39.25. CALCIUM CARBONATE occurs occasionally in the form of a cell- content, being present in tracheae or vessels and tracheids of the heart wood, as well as in the medullary rays and pith cells of certain plants. In this form it is rather characteristic of one or more genera in the following families : Aceraceae, Anonaceae, Cornacese, Cupuliferae, Rosaceae, Salicaceae, Sapotaceae, Urti- caceae, and Zygophyllaceae. When present it almost completely fills the cells, and may be overlooked or referred to as resin unless its identity is proved by the use of certain reagents. Like the other carbonates, it dissolves with effervescence on the addition of hydrochloric acid, nitric acid, acetic acid, etc., and in this way may be detected. Calcium carbonate is present in special structures known as CystolitJis. The latter are protuberances of the cell wall into the cell, and consist of a stalk and a body (Fig. 113). The stalk consists of a simple core of cellulose on which more or less silica is deposited. The upper or body portion consists of a more or less irregular spherical or ellipsoidal deposit of calcium carbonate. These are found in the parenchyma cells in roots and barks and the subepidermal cells of leaves. They are also found in epidermal cells, as in the short hairs of Cannabis satira. Cystoliths occur in certain genera of the Acanthaceae, Borraginaceae, Cucurbi- taceae, Gesneraceae, Oleaceae, Ulmaceae, Moraceae, and Urticaceae. Cystoliths occur in a number of modifications, and, while they are usually simple, yet in some of the Acanthaceae and Urticaceae branched cystoliths occur. In some of the genera of the Cucur- bitaceae 2- to 4-adjoning cells may have cystoliths, and hence are known as " double cystoliths." The cystoliths found in hairs, as CELL-CONTENTS AND FORMS OF CELLS. 201 * in Cannabis sativa, do not usually have a stalk, and are known as " hair cystoliths." The latter are, furthermore, variously modi- fied, and may have incrustations of either calcium carbonate or silica or a mixture of both of these substances. In the Begoniacese occurs a certain form of structure resembling a cystolith, but it is uncalcified, and consists of a mucilaginous substance which is =^^^l-^==::^=^/^y?=:^^ 3F^¥W£ FIG. 113. Cystolith. A cross section of a portion of the leaf of Ficus elastica showing cells of the upper epidermis (e), cells of the hypodermal layer (h), among which is a large cell containing a cystolith (c); palisade cells (ch). — After Sachs. sometimes more or less impregnated with resin. These are known as ' cystotyles." The protuberances found on the walls of certain epidermal cells and in the subsidiary cells of hairs may be either calcified or silicified, and occur in the families containing true cystoliths and also some genera of the following: Com- positae, Campanulacese, Oleaceae, Leguminosse, Hydrophyllaceas, 202 A TEXT-BOOK OF BOTANY. Scrophulariaceae, Polemoniaceae, Verbenaceae, Euphorbiaceae, and Urticaceae. SILICA is seldom found as a cell-content, and when present never occurs as a crystalline deposit, being usually in the form of amorphous masses, termed 'silica-bodies' (Fig. 109). The latter arise either in the cell-sap or the silica is deposited on the cell-wall, ultimately filling the lumen of the cell. In the palms the silica-bodies resemble stalkless cystoliths (Fig. 109, C). They may also occur in the form of long rods, being more or less fusi- form or rectangular, or in the form of discs showing a more or less sphero-crystalline structure, or in other special forms (Fig. 109). Silica-bodies have been found in the Palrnae, Orchidaceae, Podoste- maceae, and Rutaceae. Silica is insoluble in any of the ordinary solvents, being dissolved only by hydrofluoric acid. On incinerating the tissues it is not destroyed. The presence of silica may be deter- mined readily upon heating sections with sulphuric acid or any reagent that destroys organic matter. Silica usually occurs as an incrustation in the cell-wall, being found in epidermal cells, spinose hairs, and even the palisade and mesophyll cells of quite a number of plants. Siliceous walls are rather characteristic of the genera of the following families: Acanthaceae, Aristolochiaceae, Bignoniaceae, Borraginaceae, Burseraceae, Calycanthaceae, Campanulacese, Chloranthaceae, Combretaceae, Compositae, Cucurbitaceae, Dilleniaceae, Euphor- biaceae, Gesneraceae, Goodeniaceae, Hydrophyllaceae, Leguminosae, Loranthaceae, Magnoliaceae, Melastomaceae, Menispermaceae, Oleaceae, Piperaceae, Proteaceae, Rosaceae, Rubiaceae, Santalaceae, Saxifragaceae, Urticaceae, and Yerbenaceae. TANNINS AND TANNIDES.- -There is a group of water-soluble principles that occur in the cell-sap, especially of parenchyma cells, of a large number of plants. They are derivatives of phenol and phenol acids, and give either dark blue or green precipitates with solutions of ferric chloride. They were formerly designated as tannins and distinguished according to the plants from which they were obtained ; thus we had chestnut tannin, oak tannin, etc. Recent studies on the constitution of these substances show that there are two principal groups of tannins, (i) being in the nature of glucosides and (2) the other not yielding any dextrose on CELL-CONTENTS AND FORMS OF CELLS. 203 hydrolysis with acids. Both of these groups may be subdivided into two classes, namely, (A) those which probably are deriva- tives of protocatechuic acid and (B ) those which are derivatives of gallic acid. A class name has been given to include these subgroups, namely, ' tannides ' or u tannoids." The first sub- group (A) would then include the protocatechuic-tannides or -tannoids, and the second (B) would comprise the gallic-tannides or -tannoids. In working out a system of classification of this kind Kunz-Krause (Swheis. Woch. f. Cheni. u. Pharm., 1898, p. 424) has arranged all of the possible tannides or tannoids and has given the formulae for a number which have not yet been found in nature. CHEMICAL PROPERTIES OF TANNINS. — The tannins are amor- phous substances and do not form crystalline salts. They are soluble in water, alcohol,, ethyl acetate, or a mixture of alcohol and ether. They are almost insoluble in anhydrous ether, chloro- form, and the other immiscible solvents. The solutions give dis- tinct color reactions or precipitates with ferric chloride, stannous chloride, and acetates of copper and lead. They form soluble compounds with iodine and prevent the latter from giving the characteristic blue reaction with starch. Solutions of tannin give insoluble precipitates with cinchonine and other organic bases. Tannins are, furthermore, especially in alkaline solutions, powerful reducing agents, their resulting products being of a dark red or yellowish-red color. Upon treatment of tannins with dilute acids, or fusing with the alkali hydroxides, or heating alone, several classes of products are formed. i. When heated in a sealed tube at 100° C. solutions of tannin in a I per cent, solution of hydrochloric acid yield either crystal- lizable acids, or phlobaphenes, or insoluble red substances. (A) The following glucosidal tannins yield crystallizable acids : The tannin from nut-galls, divi-divi (fruit of Ccesalpinia coriaria), myrobalans (fruit of Terminalia CJicbiila], rind of pomegranate fruit, and coffee. (B} Phlobaphene is a reddish, or brownish-red, amorphous substance formed from the tannin of willow bark. It is insoluble in water but soluble in alcohol, dilute solutions of the alkalies and alkali carbonates, and solutions of borax. (C) 204 A TEXT-BOOK OF BOTANY. Quite a number of tannins yield a reddish, amorphous substance which precipitates out of the acid solution and is insoluble in water, alcohol, and solutions of the alkalies. Derivatives of this kind are obtained from the tannin of kino, krameria, etc. 2. When tannins are fused with potassium or sodium hydrox- ide several classes of products are formed, depending on the con- stitution of the tannin. (A) Protocatechuic acid is formed not only on the fusion of certain tannins, but may be prepared from other plant substances, as vanillin, asafoetida, myrrh, etc. Usually other substances are formed in the interaction, these being either acetic acid or phloroglucinol. In this class are in- cluded the most of the tannins, which on heating with dilute acids yield either phlobaphenes or insoluble red substances. (B) Pyrogallol, which is commercially prepared by the dry distillation of gallic acid, is also formed from the glucosidal tannins which yield crystallizable acids in acid solutions. 3. Upon carefully heating tannins to a temperature of 190° to 200° C. they are decomposed and yield two distinct classes of derivatives, being either (A) pyrocatechol (a diatomic phenol) or (B) pyrogallol (a triatomic phenol). Both of these substances are crystalline and may be sublimed unchanged. They are, furthermore, both soluble in water, alcohol, and ether, and are distinguished by giving very characteristic reactions with certain reagents. Solutions of pyrocatechol are colored dark green with ferric-alum and greenish with copper sulphate -f- ammonium hydrate, or concentrated sulphuric acid. Pyrogallol is colored bluish-black with ferric-alum, becoming green and finally brown ; brownish with copper sulphate -f- ammonium hydrate, or sul- phuric acid, and becoming violet with lime water, rapidly chang- ing to brown. Pyrocatechol is formed from those tannins which produce protocatechuic acids on fusion with potassium hydroxide and phlobaphenes or insoluble red substances on treatment with acids. Pyrogallol is formed on heating those tannins which also yield pyrogallol on fusion with potassium hydroxide and yield either gallic acid or ellagic acid on hydrolysis with acids. MICROCHEMISTRY OF TANNINS. — Tannin ocurs as a constituent of the cell-sap, and the cells containing it may be determined by use of dilute solutions of methylene blue, as proposed by Pfeffer, GELL-COXTENTS AND FORMS OF CELLS. 205 which colors the cell-sap blue, afterward precipitating the tannin. This reagent has the advantage that when used in very dilute solution (i part methylene blue to 500,000 of water) it does not injure the protoplasm of the living cells, so that the cut end o f FIG. 117. Phytosterol allowed to crystallize very slowly from strong alcoholic solu- tions, the crystals being recrystallized until the melting-point is constant. I, crystal forms with parallel extinction C D. II, crystals with parallel extinction B C. Ill, crystals with parallel extinction along the long axis. • IV, common crystal forms of phytosterol. Phytosterol is a constituent of most vegetable oils and is most abundant in peas, lentils, and other Leguminous seeds. The presence of vegetable oils is detected in animal oils by a study of the forms of crystals, those of phytosterol crystallizing in the monoclinic system, whereas cholesterol forms crystals which belong to the triclinic system. — After A. Bomer, in Zeits. f. U nter. d. Nahr.- u. Genussmittel, 1898, p. 45. and warm alcohol. In solutions of ether or chloroform it is pre- cipitated upon the addition of acetone. In contact with water, it separates in the form of spiral threads or loops, giving rise to the ' myelin forms ' of Kirchow and Beneke. When examined under the microscope a smear of lecithin, to which a drop o'f water or a sugar solution has been added, sends out a number of •2 1 6 A TEXT-BOOK OF BOTANY. rounded projections which gradually elongate and become more and more abundant and intricate. If this process be allowed to take place in a test-tube or other vessel that can be shaken, the water becomes turbid through the dispersion of the delicate microscopic myelin protrusions, and in course of time a uniform emulsion of the lecithin in water is obtained, which consists of fine swollen particles. This is a colloidal solution that can be filtered without change. It is not coagulated by heat, nor precipitated by salts of monobasic or tribasic metals. \YAX.--The epidermal layer of the plant shows a number of modifications. It usually consists of an inner layer of cellulose and an outer covering of cutin. While some of the lamellae be- neath the cutin may be modified to mucilage or oil, the surface of the cutin layer may have deposited upon it a coating of wax. Frequently the wax is in such small quantities that it is not ob- served until the sections are heated to a temperature of 90° to 100° C, when the wax separates in the form of oily globules. According to De Bary, there are four principal forms of wax- coatings. i. It occurs in the form of minute rods or needles, such as are found constituting the bloom of fruits as the grape and plum, and the stems and leaves of Eucalyptus Globulus, Ricinus corn- munis, etc. 2. The most common form is a simple, granular coating consisting of isolated grains which may lie together as a single layer. These are found in the fruits of some of the Crucifene, Iris pallida, etc. 3. The coating may consist of minute rods which may be more or less bent or curled, standing perpendicularly on the cuticle, as in the sugar cane, canna, banana plant, etc. 4. The wax incrustation may occur in the form of membrane-like layers, varying from thin scales, as in Ta.vus baccata, Portnlaca olcracea, and various cacti, to thick layers showing a striation and stratification similar to that found in thick-walled cells, as in the fruit of Myrica, leaves of the wax palm (Ccro.\-ylon andicoluin). According to Wiesner, the deposit of wax is often crystalline, appearing in four-sided prisms. (Con- sult A. deBary, Comparative Anatomy of the Organs of Vegetation.") PHYSIOLOGY OF FATS. — It is stated that in the photosynthetic CELL-CONTENTS AND FORMS OF CELLS. 217 processes of some of the lower plants, as Vaucheria, Diatoms, etc., fixed oils rather than starch are formed in the chromatophores. It is well known that in the cells of the bark of a number of plants fixed oils are stored in place of carbohydrates. These facts show that there is a very intimate relationship between the fixed oils and other metabolic substances. Fixed oils constitute the reserve materials in seeds, spores, pollen grains, and are even present in the tubers of certain plants as Cy penis esculcntus. The storing of fixed oils instead of starch may be of some advantage to plants, in that there is a greater supply of energy contained in them than is present in the same quantity of any of the carbohydrates. Again, as the specific gravity of the fixed oils is less than that of the carbo- hydrates, this is an advantage in those spores or seeds which are disseminated by the wind and require to be as light as possible. The fixed oils are more or less intimately associated with the protoplasm occurring in vacuoles of the same in fruits and seeds. The waxes which are secreted in the epidermal cells of leaves and 'green stems, and also found as a covering of many fruits, serve to protect the underlying cells from loss or excess of moisture, from the attack of disease-producing micro-organisms, and also prevent the interactions caused by some of their enzymes. The resistance of certain micro-organisms, as the tubercle-bacilli, is supposed to be due to some extent to the fatty substances in which their bodies are enclosed or with which they are impregnated. ' It is held by some that the fats, or, more correctly, the lecithin and phospholipines, are essential to the cohesion and physical constitution of the protoplasm, so that any interference with the physical state of these substances arrests the vital functions. The cement which binds the organized matter together is loosened by the solution in it of foreign substances, and it is the loosening of the protoplasmic cement that makes it possible for the normal processes of life to be carried on. ' Attempts to form a concrete conception of the physical rela- tionship in the structural organization of cells between fats on the one hand and the other constituents of living matter on the other have not been successful. Some have spoken of ' lipoid mem- branes ' as if the living cell itself were enclosed in a fatty envelope and accessible only to such substances as can permeate this envelope 218 A TEXT-BOOK OF BOTANY. through chemical affinities with the fatty material of which it is composed. Others are inclined to think of protoplasm as an emulsion of proteins and ' lipoids.' Loeb and v. KnafT Lenz find that sea-urchin eggs are liable to undergo cytolysis under the action of any process, chemical or physical, that causes the cell fats to become more fluid." (Consult J. B. Leathes, "The Fats.") Mucilages and Gums. — By the terms mucilages and gums are meant those substances which are soluble in water, or swell very perceptibly in it, and which, upon the addition of alcohol, are precipitated in the form of a more or less amorphous or granular mass. Mucilage originates in the plant as a cell-content, or as a modification of the wall. In the former case it arises as a product of the protoplasm, or it may be a disorganization product of some of the carbohydrates. \Yhen it arises through modification of the wall it is spoken of as 'membrane mucilage," and owes its origin to several causes : either to a secondary thickening of or an addition to the cell wall, or a metamorphosis of it, at least in part. In the latter case it may arise either as a disorganization product of the primary wall, or of the subsequent lamellae making up the walls of the cells of the medullary rays, parenchyma, and other tissues, as in Astragalus gummifer (Fig. 118), or it may arise as an intercellular substance. The following is a classification of some plants, based upon the origin of the mucilage: I. Mucilage in the form of a cell-content is of infrequent occurrence in plants. It is usually present in the cells containing raphides, especially in the Monocotyledons. Its orgin and de- velopment may be easily followed in the tubers of a number of Orchids, especially those yielding salep. The mucilage arises very early in the development of the cells surrounding the crystal- groups, and continues to be formed as the crystals grow in size, the protoplasm and nucleus being reduced to a very thin layer which lie next to the cell-wall. The mucilage ot salep is colored yellowish with iodine and sulphuric acid, or a yellowish-red or rose-red with aqueous eosin solution, and a carmine-red with an aqueous solution of Congo red. The cells containing mucilage are easily differentiated from the surrounding cells by the use of CELL-CONTENTS AND FORMS OF CELLS. 219 alcoholic solutions of Congo red, methylene blue, etc., which dis- tinctly color the mucilage in them. Cell-content mucilages are also found in the fleshy scales of the onion, the rhizome of Agropyron repcns, the fleshy leaves of Aloe and other succulent plants. It ms mst m FIG. 118. Cross section through pith (m) and the inner portion of the wood (Ib) of Astragalus gummifer, showing successive stages in the modification of the walls in the formation of gum tragacanth (o, i, 2, 3, 4). Some of the tracheae (c) contain globular masses of gum. — After Tschirch. probably also occurs in this form in the Cyanophyce?e and in some of the red algae, as Laminaria, although in the latter it is formed chiefly as a modification of a cell-wall and the intercellular substance. In Dicotyledons the mucilage which is present is 22O A TEXT-BOOK OF BOTANY. usually formed as a modification of the cell-wall, and, according to Solereder, it seems to occur in the contents of the cell in only the following families : (Enotheraceae. Rubiaceae, and Vitaceae, in A FlG. 119. Cell-wall mucilage. A, transverse section of seed-coat of flaxseed treated with water, showing the swelling of the mucilaginous layer situated beneath the cutin; B, section of Althaea root showing three large mucilage-cells; C, transverse section of elm bark showing four large mucilage-cells. all of which the mucilage receptacles can be interpreted as being incompletely differentiated raphide-sacs, — i.e., without raphides. II. Cell-membrane mucilage, — i.e., mucilage formed as a CELL-CONTENTS AND FORMS OF CELLS. 221 result of a metamorphosis of the cell-wall, — is of frequent occur- rence, being found in all parts of the plant, including the endo- sperm cells of seeds, parenchyma cells and medullary ray cells of roots and stems, and epidermal cells of leaves, stems, fruits, and seeds. Cell-membrane mucilage is also found in some of the mucilaginous marine algae, as chondrus laminaria, etc., although in the latter case the mucilage is often spoken of as being derived from the intercellular substance, being a modification of the FIG. 120. A, B, C, successive stages in the development of the mucilage hairs or glands on the lobes of the leaves of Viola tricolor; D, young secretion hair showing some of the cells with large nuclei and several vacuoles; E, mature hair; F, gland showing mucilaginous layer beneath the cutin and the protrusion of a portion of the mucilage through the broken wall; G, portion of leaf on the upper part of the lobes of which occur the mucilage glands. primary wall. It may also occur as a result of a decomposition of the secondary lamellae. Four different forms of mucilage are recognized. I. Mucilage cells, or distinct cells resembling more or less the surrounding cells, except that they contain mucilage, occur in the tissues of leaves, petals, fruits, seeds, and the parenchyma cells of pith and primary cortex of a number of plants. In this group may also be included the gelatinized cells of the integumental tissues 222 A TEXT-BOOK OF BOTANY. (epidermis and hypodermis), as these in many cases may be mistaken, as in the Violaceae, for distinct cells, although only the inner walls of the epidermal cells are gelatinized. 2. Mucilage cavities arise from the simultaneous gelatinization in the walls of a group of cells. These are found in the cells of the pith, cortex, and petioles in a number of plants of the Malvaceae, Sterculiaceae, Simarubaceae, etc. 3. Mucilage canals are large cavities formed either (A) as a result of the enlargement of the intercellular spaces between the cells, the primary lamellae being modified to mucilage; or (B) are formed by the disintegration or breaking down of a number of cells, the walls of which become gelatinized. In the former case they are spoken of as " schizog- enous canals," and in the latter as " lysigenous canals." The latter are the more common form and occur in the pith and primary cortex of a number of plants belonging to the Guttiferae, Malvaceae, Sterculiaceae, Oleaceae, Rhamnaceae, Vitaceae, Legumi- nosae, Rosaceae, Cactaceae, Piperaceae, Moraceae, and Urticaceae. 4. Glandular hairs (Drusensotten) . In this form (Fig. 118) they are found in the lobes of the leaves and calyces of Viola tricolor, Coffca arabica, and of Primus aviitm. CHEMICAL CLASSIFICATION OF MUCILAGE. — Mucilages may be distinguished, according to their behavior with special reagents, as cellulose-mucilages or pectose-mucilages. The former are colored blue by chlor-zinc-iodide, and are soluble in ammoniacal solution of cupric oxide. To this class belong the mucilages of the tuber of salep and the seeds of cydonium. The pectose- mucilages are distinguished by the fact that they are dissolved on being heated with solutions containing from 35 to 65 per cent, cane sugar. They are also stained intensely with solutions of saffranin, methylene blue, or ruthenium red. Mucilage is formed in large quantities in certain trees, and the exudation which is collected forms the so-called gums of com- merce. As these are largely used for a variety of technical pur- poses, their chemical properties have been studied, so that four distinct classes of gums are recognized. i. Gums containing arabin or arabic acid. In this group are included gum arabic, obtained from Acacia Senegal and other species of Acacia ; Feronia gum, obtained from Fcronia clcphan- CELL-CONTENTS AND FORMS OF CELLS 223 turn (Fam. Rutaceae), and Anacardium gum, obtained from Anacardiuni occidcntale. 2. Gums consisting of mixtures of arabin and cerasin (cerasic acid). To this group belong the exudations formed on a number of trees of the Rosacese, as cherry, almond, apricot, and plum. 3. Gums containing bassorin. Tragacanth is the typical gum FIG. 121. Citrus vulgaris. Longitudinal section of a young fresh fruit showing a lysig- enous oil canal or duct. Se, oil; Zs, cell sap; PI, cells in which the walls have been dis- solved; f, thin-walled cells; D, thick-walled cells; K, nucleus; Chr, chromoplasts; o, crystals of calcium oxalate; e, epidermis. — After Meyer. of this class. Included in this group are a few other gums which find some commercial use, as cocoa-palm gum, obtained from the bark of the cocoa-nut palm; chagual gum, obtained from Pu\a coarctata (Fam. Bromeliacese), and Moringa gum, obtained from Moringa pterygosperma (Fam. Moringaceae). 4. Gums containing mixtures of cerasin and bassorin. The East Indian gum, obtained from Coc'hlospermum Gossypium 224 A TEXT-BOOK OF BOTANY. o FIG. 122. Development of schizogenous oleo-resin canals in Brauneria pallida. A, intercellular space (o) between four parenchyma cells, being the seat of the early formation of the canal and indicated by a yellowish oily content. B, intercellular oleo-resin canal with five surrounding parenchymatous cells (p). C, later stage of canal showing separation of small oily globules in the intercellular substance. D and E, the intercellular substance showing an almost protoplasmic-like structure, some of the lining cells being developed as papillae and suggesting that they might be in the nature of secretion cells, although it is now considered that the oils and resins of this character are formed from a resinogenous layer in the wall. F, longitudinal section showing the elongated secretory canal between the rows of cortical parenchyma. CELL-CONTENTS AND FORMS OF CELLS 225 (Fam. Cochlospermaceae), has been used as a substitute and adulterant of tragacanth. VOLATILE OILS AND RESINS.- -These and related products, known as gum-resins and balsams,* are found in a very large number of plants. Like the mucilages, they originate either as a metamorphosis of the cell-wall or as a direct product of the protoplasm. The former is of more frequent occurrence, and the B FIG. 123. Development of a lysigenous secretory canal in the leaves of Dictamnus albus (Fam. Rutaceae). The development begins partly in the cells of the epidermal layer and partly in the underlying parenchyma (A). The outer cells divide, forming the secretion cells (c), while the inner give rise to the reservoir (B). The innermost cells then multiply by repeated division in all directions, giving rise to a large number of cells containing globules of oil (C). Later the thin walls are absorbed and the oily globules fuse together, forming a single large globule (D). — After Rauter. The volatile oils are not infrequently associated with other sub- stances of the plant cell in varying proportions, as resin, gums, cinnamic and benzoic acids. Those products which consist chiefly of oil and resin are known as OLEO-RESINS, and include turpentine and copaiba; those consisting chiefly of gum and resin and containing but little volatile oil are known as GUM-RESINS, and include ammoniac, asafoetida, galbanum, and myrrh ; oleo-resins associated with aromatic acids are known as BALSAMS, as balsam of Tolu, balsam of Peru, storax, and benzoin, which latter is usually termed a balsamic resin. 15 226 A TEXT-BOOK OF BOTANY. layer of the wall in which the decomposition takes place has been termed by Tschirch a resinogenous layer. The cells or receptacles which contain oils, resins, gum-resins, and balsams are usually referred to as ' secretory cells ' or " secretory receptacles." The latter term is used by Solereder to include all cells, cell fusions, cavities or canals which are filled with secretions. Usually no attempt has been made to determine whether the secretion is a volatile oil or a resin, or a gum-resin or a balsam, as the appearance of the secretion is always either in the form of globules or more or less rounded masses. Secretory receptacles may arise in three different ways. ( I ) As a modi- fication of the intercellular substance and an enlargement of the intercellular areas, giving rise to schizogenous receptacles (Fig. 122). (2) As a result of a disintegration of a group of cells and a decomposition of the wall substance, forming lysigenous receptacles (Fig. 123). (3) They may have at the outset a schizogenous origin, but later the surrounding cells in addition break down, so that the receptacle is more properly designated as being schizo-lysigenous. In certain plants, as in the bark of Sassafras and Cinnamon, there is a more or less even distribu- tion of cells in the cortex, containing volatile oil, on the one hand, and mucilage, on the other. Indeed, it is supposed that the cells giving rise to mucilage may under different conditions develop volatile oil. In a general way it may be said that the secretory receptacles resemble those containing mucilage, both as to the manner in which they originate in a plant and the physical char- acters of the secretion. Indeed, they may be closely related to the mucilages in that they may contain a large proportion of gum, or the proportion of oleo-resin and gum may be reversed. In the examination of technical products, and especially in taxonomic work, it is very important to note not only the chemical character of the secretions but also the fact whether the cells are isolated or whether they form canals, or whether the secretory receptacle is only a cavity. The following facts may be given in reference to the four principal types of secretory receptacles: i. Secretory cells are distinct cells which may be quite dis- tinct from, or may show more or less resemblance to, their neighboring cells, except that they contain oil or resin. They CELL-CONTENTS AND FORMS OF CELLS. 227 vary in length and outline, being either spherical, ellipsoidal, sac- shaped (Fam. Bixaceae), or branched (Fam. Meliaceae). The contents may be in the form of distinct globules adhering to the wall (or in dried material may be in the form of amorphous masses), varying in color from colorless to yellowish or even dark brown. In the secretory cells of certain plants of the Lauraceae, Magnoliaceae, Canellaceae, Aristolochiaceae, and Piperaceae the secretory contents are enveloped by a thin-walled sheath, con- nected with the cell-wall by means of a stalk. The internal glandu- lar hairs occurring in the rhizome of Dryopteris and in Pogoste- mon Patchouli may be included among secretory cells, although they project into the intercellular area rather than into the cells. The cell-wall of the secretory cells not infrequently gives a dis- tinct reaction for suberin. Elongated secretory cells or sacs, resembling tannin-idioblasts, and with diverse contents varying from resin to latex-like sub- stances or tannin-like masses, are distributed in the cells of the pith, bast, and pericycle of the stem and occasionally in the larger veins of the leaves of some of the genera of the following families : Anacardiaceae, Berberidaceae, Caprifoliaceae, Compositae, Crassu- laceae, Euphorbiaceae, Lecythidaceae, Leguminosae (very widely distributed and with diverse contents), Menispermaceae, Monimi- aceae, Myristicaceae, Passifloriaceae, Polygonaceae, Rosaceae, and Rubiaceae. Solereder also states that similar elongated sacs with brownish contents are observed in the epidermal cells and occasionally in the upper layers of mesophyll of one or more of the genera in the following families : Crassulaceae, Euphorbiaceae, Geraniaceae, Moraceae, Saxifragaceae, and Violaceae. 2. Secretory cavities are either spherical or ellipsoidal in shape and the contents vary from oily or resinous to gum-like or tannin- like masses. The mode of development of the cavities, as to whether schizogenous, etc., is usually not considered, as this fact is not easily determined in the mature tissues. \Yhen occurring in leaves the cavities give rise to transparent dots or glandular punctate areas. They are also found in the pith and primary cortex of quite a number of plants. There are a number of special forms of secretory cavities, the 228 A TEXT-BOOK OF BOTANY. latter in some cases being lined by a papillose epithelium or a form of bracket-cells, etc. They are found in the following fami- lies : Araliaceae, Bixaceae, Caesalpinaceae, Compositae, Connaraceae (with sphaero-crystalline contents), Euphorbiaceae (with bracket- epithelium), Geraniaceae (with sphaero-crystalline contents), Gutti ferae, Leguminosae (intramural glands with a papillose epi- thelium or bracket-epithelium), Lythraceae, Malpighiaceae, Mal- vaceae, Meliaceae, Menispermaceae, Myrtaceae, Oleaceae, Passi- floriaceae, Piperaceae, Podostemaceae, Polygalaceae, Polygonaceae (secretory cavities sometimes formed from four epidermal cells), Primulaceae (occasionally with red crystalline contents), Pro- teaceae (intramural glands), Rhamnaceae (with a papillose epi- thelium), Rosaceae, Rubiaceae, Rutaceae, Simarubaceae, Styracaceae. and Theaceae. 3. Secretory canals differ from secretory cavities in that they are more or less elongated receptacles and often referred to as oil-ducts or oil-tubes. Like the secretory canals, they originate variously and have diverse contents. They may occur in a number of different portions of a plant, but their distribution is quite characteristic of certain genera or even of families. Secre- tory canals have been observed in the following families : Ana- cardiaceae, Araliaceae, Burseraceae, Cactaceae, Caesalpinaceae, Celastraceae, Compositae, Gesneraceae, Guttiferae, Hamamelidaceae, Leguminosae, Pittosporaceae, Podostemaceae, Rhamnaceae, Ruta- ceae, Simarubaceae, Theaceae, and Umbelliferae. (Consult Sole- reder's ' Systematic Anatomy of the Dicotyledons.") 4. Glandular hairs. Volatile oils and resins arise in the glandular hairs formed on the surface of stems, leaves, and various parts of the flower in the Labiatae, Compositae, and other families. In these hairs a volatile oil separates in the form of large, oily globules which lie between the cuticle and the outer wall of the underlying cells (Fig. 124). The origin of this secre- tion has been variously ascribed to the protoplasmic content of the cell or to a modification of the cell-wall. In the former case it is said to arise as a metabolic substance in the protoplasm, and is later diffused into the glandular area between the outer cellulose wall and cuticle. While this manner of formation of the oily secretion would seem reasonable, yet the studies by Tschirch CELL-CONTENTS AND FORMS OF CELLS. 229 and Tunmann would seem to show that the secretion in the glandular hair arises in a subcutaneous layer of the wall, which has been termed a " resinogenous layer." Even De Bary, with char- acteristic caution, has stated that the secretion found in the walls of glandular hairs originates in the wall even though the ma- terials for its formation must arise in the protoplasm of the cells. In the study of glandular hairs the method of Tunmann may be followed (Bcr. d. d. phartn. Gescllsch., 1908', p. 513). Fresh, or even dried, material may be used. Surface sections are made FIG. 124. A glandular hair from the young leaves of Lavandula vera seen in different stages in the course of three days, showing that the underlying cells remain of the same size and structure, but that there is a gradual increase in the glandular area or resinogenous layer. — After Tunmann. and examined in aqueous solutions containing 10, 20, 30, or 40 per cent, of hydrated chloral. The 10 per cent, solution is used first, then the 20 per cent., etc. The proper solution renders the hair transparent, dissolves the resin, and, if the cover-glass is moved sidewise, the cuticle bursts, showing the resinogenous layer. Tunmann distinguishes three different types of glandu- lar hairs, depending upon the character of this resinog- enous layer. ( i ) In which by this treatment there separate small rod-like crystals resembling bacteria, as in Fig. 125, A, B, C. (2) A second type is given in which vacuoles occur consisting of 230 A TEXT-BOOK OF BOTAXY. rsg. FIG. 125. Several lorms of glandular hairs: i. In which the resinogenous layer (rsg) separates in the form of small rods, as the leaves of violets (A), Fraxinus (B), and Alnus (C). 2. The resinogenous layer separating in the form of vacuoles in the hairs of Salvia (D) and Hyssopus (E), observed in the dried material treated with dilute solutions of hydrated chloral. 3. A lattice-like or cellular resinogenous layer occurring in the hairs of Rhodo- dendron (F) and Azalea (G). — After Tunmann. CELL-CONTENTS AND FORMS OF CELLS. 231 a fine net-work, as in Fig. 125, D, E. (3) A third type in which the secretion is in the form of neither rods nor vacuoles but a somewhat cellular structure, termed by Tunmann a lattice-work. In the walls of the glandular hairs other substances are some- times present, as resins, gums, etc. Hanstein originally pro- posed the use of a mixture of aniline dyes to distinguish resin, gum, and protoplasm (Bot. Zeit., 1868, p. 754), but later studies have shown that these dyes are limited in differential diagnosis of many of these substances. The cells of the glandular hairs may contain, in addition to protoplasm, protein bodies, chloro- phyll grains, starch, fixed oil, tannin, calcium oxalate, reducing sugars, and other special substances, which are colored yellowish- red with solutions of the alkalies or sulphuric acid. MlCROCHEMISTRY OF THE VOLATILE OlLS AND RESINS.- -They are readily soluble in alcohol, ether, chloroform, benzene, acetic ether, carbon disulphide, petroleum ether, etc. They are also quite soluble in glacial acetic acid and in aqueous solutions of hydrated chloral. Some of them are soluble in dilute alcohol. They may be liberated on the heating of sections for about ten minutes in a drying oven to a temperature between 100° and 130° C. Like the fixed oils, they are colored brownish or brownish-black with osmic acid and are intensely colored with alkannin and cyanin. The volatile oils are also colored a carmine red with very dilute solutions of fuchsin. Cells containing resins and terpenes are colored green by the use of aqueous solutions of copper acetate, the freshly cut twigs or leaves being allowed to remain in the solution for a few days. VOLATILE OILS.- -The odors which are characteristic of very many plants are due chiefly to a group of principles known as volatile oils. They are, for the most part, mixtures of terpenes and camphors, and are obtained from the plant by distillation with steam, the oil rising to the surface of the distillate, being only slightly soluble in water. Volatile oils are readily soluble in alcohol, ether, chloroform, and in the fixed oils. Some of them show a tendency to absorb oxygen, and are converted into resinous substances. They are widely distributed and are char- acteristic of certain families, viz. : Pinacese, Crucifene. Labiate, Lauracese, Myrtacese, Rutacese, and Umbelli ferae. 232 A TEXT-BOOK OF BOTANY. With the exception of the seeds, in which they are seldom found, volatile oils occur in nearly all parts of the plant. They are formed either as a direct result of the activities of the pro- toplasm or by reason of changes in some of the constituents of the cell-wall. In a few instances the volatile oil is formed from a mother substance, being in the nature of a glucoside, and in this form occurs in the seeds of the almond and mustard. BOTANICAL CLASSIFICATION.- -The composition of volatile oils is in many cases very complex ; seldom do they consist of only one substance, as in turpentine oil. Usually they consist of a number of chemical compounds, the most complex being American peppermint oil, from which no less than seventeen different, well-characterized chemical compounds have been isolated. As the volatile oils are of considerable economic value, they have been rather very extensively studied. It remains for botanists to apply this knowledge to the study of the living plant. The physiologist will find the study of the origin, transportation, and localization of volatile oils in different parts of the same plant of very great interest. Such studies will throw considerable light upon the entire question of origin and transformation of the different plant constituents. In many cases, even the constitution of the constituents in volatile oils has been ascertained, so that on a sound scientific basis, hypotheses may be developed con- cerning the complex changes which are possible in the substances derived from the protoplasm. Again, the distillation products obtained in the study of volatile oil show that the living plant may contain such simple compounds as formic alcohol, formalde- hyde, formic acid, hydrocyanic acid, etc. Volatile oils which have been carefully studied are obtained from plants of the following families : F*olypodiaceae, Pinacese, Pandanaceae, Gramineae, Palmar, Araceae, Liliaceae, Iridaceae, Zingi- beraceae, Piperaceae, Salicaceae, Myricacese, Juglandaceae, Betu- laceae, Moraceae, Aristolochiaceae, Chenopodiaceae, Ranunculaceae, Magnoliaceae, Anonaceae, Myristicaceae, Monimiaceae, Lauraceae, Cruciferae, Resedaceae, Hamamelidaceae, Rosaceae, Leguminosae, Geraniaceae, Tropaeolaceae, Erythroxylaceae, Zygophyllaceae, Rutaceae, Burseraceae, Meliaceae, Polygalaceae, Euphorbiaceae, Anacardiaceae, Vitaceae. Tiliaceae, Malvaceae, Theaceae, Diptero- CELL-CONTEXTS AND FORMS OF CELLS. 233 carpaceae, Cistaceae, Turneraceae, Lythraceae, Myrtacese, Aralia- ceae, Umbelliferae, Ericaceae, Primulaceae, Convolvulaceae, Ver- benaceae, Labiatae, Solanaceae, Caprifoliaceae, Valerianaceae, and Compositae. COMPOSITION OF VOLATILE OILS. — The volatile oils are usu- ally of a very complex composition ; it will be found, however, that they owe their principal characteristics to one or more definite compounds. The following classes of compounds have been derived from the volatile oils. TERPENES, hydrocarbons of the formula C10H16, are found in the volatile oils of the Pinacese, Rutaceae, etc. The terpene pinene makes up practically the entire bulk of turpentine oil. The terpene limonene is found in the oil of lemon to the extent of 90 per cent. It is not, however, the characteristic constituent in this oil, the odor of lemon being due to an aldehyde, citral. SESQUITERPENES, hydrocarbons of the formula C15H24, have been isolated from a number of oils, the best known representa- tive of this class being cadinene, occurring in the oils of cubeb, patchouli, savin, etc. ALCOHOLS belonging to the aliphatic and aromatic series occur in a number of oils combined as esters with the fatty acids. Both methyl alcohol and ethyl alcohol are found in the aqueous dis- tillates in the preparation of certain oils. This occurrence is usually explained as being due to the decomposition of other sub- stances. Methyl alcohol is thought to be derived from the de- composition of cellulose, while ethyl alcohol is considered to be a product of the fermentation of carbohydrates. That ethyl alcohol may be derived in this manner is probable from the obser- vations of Maze, who obtained alcohol from germinating seeds. Esters of methyl alcohol, especially methyl salicylate, are widely distributed. Among other alcohols, the following may be men- tioned : Linalool constitutes the bulk of lignaloe oil ; geraniol, a diolefinic alcohol makes up the bulk of rose oil ; benzyl alcohol, as an ester, occurs in the oils of jasmine, tuberose, ylang-ylang, etc. ; cinnamic alcohol, as an ester, occurs in cassia oil, storax, and Peru balsam ; menthol (peppermint camphor) , a secondary alcohol, is found in peppermint oil; borneol (camphyl alcohol) occurs 234 A TEXT-BOOK OF BOTANY. in the oils of valerian and serpentaria, the acetate of this alcohol being found in many oils of the Pinacese. ALDEHYDES.- -The simplest of the aliphatic aldehydes, for- maldehyde, has been found in apopin oil, the latter being derived from an unknown plant growing in Japan. Acetaldehyde is com- monly present in the distillates of seeds. Citral is found in lemon oil, giving it its characteristic odor. It is also found in the oils distilled from the leaves and twigs of the lemon tree, sweet orange tree, sassafras, etc. Benzaldehyde is formed upon the hydrolysis of amygdalin. KETONES. — Of the aliphatic ketones, acetone has been ob- served, together with hydrocyanic acid, in the distillation of a number of leaf oils. Carvone occurs in the oil of caraway. Pulegone occurs in large amounts in European pennyroyal oil and the oils of other members of the Labiatce. Japanese or laurel camphor is obtained by the distillation of the wood of Cinnamomum Camphora. Irone, a cyclic ketone, occurs in orris root. PHENOLS AND PHENOL ETHERS are found in a number of volatile oils. Thymol constitutes the larger part of the oil of ajowan (Ptychotis coptica)'. Carvacol is a constituent in many Labiate oils. Anethol is the principal constituent of the oils of Pimpinclla anisatum and Illicium verum and is an important constituent in the oil of fennel. Eugenol occurs in the oils of the Myrtacccc and Lauracecc. Apiol is a constituent of the fruit of parsley, and safrol is the principal constituent of sassafras oil. ACIDS. — Quite a number of acids are obtained as a by-product in the aqueous distillation of volatile oils. Among these may be mentioned formic acid, acetic acid, isovaleric acid, benzoic acid, cinnamic acid, salicylic acid, etc. ESTERS give the fragrance to most volatile oils. Some oils consist almost entirely of esters, as wintergreen oil and birch oil, which contain methyl salicylate. The latter is probably one of the most widely distributed of the esters. Linalyl acetate is the characteristic constituent of bergamot and lavender oils. Geranyl acetate is found in the oils of lemon grass, neroli, CELL-CONTENTS AND FORMS OF CELLS. 235 coriander, etc. Esters of benzoic and cinnamic acids are found in storax, Tolu balsam, and Peru balsam. Bornyl isovalerate occurs in valerian oil. LACTONES.- -The odoriferous principle known as coumarin is widely distributed in the plant kingdom. It occurs in some of the ferns, grasses, tonka bean, Waldmeister ' (Asperula odorata), etc. It apparently is formed as the result of the action of a ferment, as it is detected only after the drying of the plant. Alantolactone is the principal constituent of the oil of Innla Helenium. NITROGEN AND SULPHUR COMPOUNDS occur frequently in the aqueous distillates of plants yielding volatile oils. Hydrocyanic acid is readily detected by means of Prussian blue, and occurs in the distillates not only of cyanogenetic plants but in a large num- ber of others as well. The mustard oils are esters of isothio- cyanic acid and are characterized by their penetrating odors. Allyl mustard oil is obtained from the seeds of Sinapis nigra and a few other plants of the Cruciferae. (Consult "The Volatile Oils," Gildemeister and Hoffman, translation by Edward Kremers ; also " Semiannual Reports," by Schimmel £ Co.) FORMATION OF VOLATILE OILS. — The chemical study of odorous principles shows that they vary considerably in their' composition. Not much is known regarding the formation of volatile oils. Charabot and Herbert have suggested that the esters may originate in the cells containing chloroplastids. They suggest that under the influence of an enzyme of reversible activity the esters are formed from the acids and alcohols present in the plant cell, and that they continue to form until the flowering period. They are then diffused to other parts of the plant, notably the inflorescence. While some of the oils are indirect products connected with photosynthesis, others arise through the decom- position of a mother substance, as the glucosides, and still others originate as a metamorphosis of the cell-wall. PHYSIOLOGICAL ROLE OF OILS. — It is usually considered that volatile oils occurring in receptacles near the surface of the plant, as in fruits like the orange, serve to prevent the entrance of animal and vegetable parasites, and thus prevent disease. Again, the oils which are found in glandular hairs covering the leaves 236 A TEXT-BOOK OF BOTANY. and stems of many plants are supposed to be useful in preventing depredations by animals. The odorous principles which occur in many flowers are supposed to exert a directive influence upon insects and thus assist in the work of cross-pollination. \Yhile biologists usually consider the volatile oils as serving ecological uses yet those investigators, who study the perfume-yielding con- stituents very closely, are inclined to consider them as being in the nature of food materials that are used after the fertilization of the flower and during the development of fruit and seeds. RESINS, GUM-RESINS AND BALSAMS. — A large number of this class of plant products are found in commerce and used in medi- cine and in the arts. A few of these occur as normal products FIG. 126. Menthol: A. individual crystals obtained by sublimation; B, the commonly occurring aggregates of very fine needles. in living plants, as the gum-resins of the Umbelliferse, the gum- resin euphorbium, and the resins of mastiche and sandarac. Most of the others arise as a' result of wounds in plants and are in the nature of pathological products, as benzoin, styrax, Tolu balsam, Peru balsam, etc. Until recently not much was known except in a general way regarding the composition of resins. Largely through the researches of Tschirch and his students the nature and the constitution of the important constituents in a number of the resins have been worked out. As a result of these studies seven principal groups of resins are recognized. i. Tannol Resins- -These are esters of aromatic phenols and CELL-CONTENTS AND FORMS OF CELLS. 237 behave toward iron salts and some other reagents like tannin. They are found in relatively large amounts in a number of the resins and balsams, and occur in rather widely separated families, as follows: Peru balsam and Tolu balsam obtained from certain members of the Leguminosae, styrax from the Hamamelidacese, benzoin from the Styracacese, aloe from the Liliaceae, dragon's blood from the Palmse, and the resins from the Umbellifene, in- cluding ammoniac, galbanum, asafoetida, etc. 2. Rescue Resins- -These are mostly colorless, indifferent substances occurring in resins and are not only insoluble in potassium hydroxide but exceedingly resistant to it, and are not capable of acetylization. To this group belong the resinous exudations of the Burseraceae, including myrrh, olibanum, and elemi ; also of the Anacardiacere, including mastic ; and of the Dipterocarpaceae, including gurjun balsam and dammar. 3. Resinolic Acid Resins.- -These are oxy-acids containing either or both hydroxyl and carboxyl groups. They form color- less crystals and are either free or combined with alcohol in the form of esters. They have an acid reaction and are soluble in solutions of sodium hydroxide, and with difficulty form com- pounds with acetyl chloride. Acids belonging to this group have been obtained from a number of the resinous exudations of the Coniferse, including sandarac, Canada turpentine, and Strass- burg turpentine. It is also obtained from a number of resins which are in the nature of pathological products, as larch turpen- tine, Jura turpentine, and French turpentine. The abietic acid in colophony and the succinoabietic acid found in the fossil resin known as amber, also belong to this class of acids. Furthermore, resinolic acids are found in the fungus Polyporus officinalis, and in some of the exudations of the Leguminosse, including the oleo- resin known as copaiba and the recent-fossil resin, Zanzibar- copal. 4. Resinol Resins. — Resinols are aromatic alcohols which usually form colorless crystals and occur either free or in the form of esters. The principal constituents of guaiac resin belong to this class, namely, guaiaconresinol (guaiaconic acid), guaiacresinol (guaiacic acid), and guaiacinresinol (guaiacinic acid). Resinols are also found in small quantities in other resins. 238 A TEXT-BOOK OF BOTANY. 5. Fatty-resins. — The resins of this class differ from the others heretofore considered in that they are derivatives of some of the fatty acids. To this group belongs the resinous exudation known as ' stick-lac," occurring on a number of trees growing in the East Indies, being caused by the punctures of a hemipterous in- sect, Coccus lacca. 6. Pigment Resins. — In this group are included those exuda- tions in which the resins are combined with a chromogenic deriva- tive. These have been studied but very little, and the best repre- sentative of this class is gamboge, which is used in medicine as well as for coloring in art. 7. Glucosidal Resins. — This group includes, as the name would imply, those resins which are in the nature of glucosides and yield on hydrolysis glucose as well as some other derivative. The resins found in jalap, scammony, and other plants of the Convolvulacese belong to this group. (Consult A. Tschirch, " Die Harze und die Harzbehalter.") ORIGIN OF RESINS. — It was at one time considered that the resins were derivatives of tannin. Now that Tschirch has shown that there are a class of resinous substances that give reactions for tannin, it might seem that this theory would receive additional support. However, as he himself explains, the resinotannols con- tain a great deal more carbon than the tannins. Furthermore, Tschirch has shown that a number of the constituents of the resins give color reactions with Liebermann's reagent for phy- tosterol. On the other hand, a number of these same constituents do not give the characteristic color reaction for phytosterol with Salkowsky-hesse's reagent. "With regard to the resins of the resinolic acid series, Tschirch concludes that they are probably not derived from volatile oils, but that they are derivatives of a common mother substance. In a later publication Tschirch ( " Chemie und Biologic der Pflanzlichen Sekrete ") states that in all probability all the secretory products, formed as a meta- morphosis or decomposition of the resinogenous lamelke, are the direct products of ferments accompanying these layers. LATEX OR MILK- JUICE is the product formed in special secre- tory organs in the plant, and exudes readily on even very slight injury of the plant. Under the microscope it is seen to be in CELL-CONTENTS AND FORMS OF CELLS. 239 the nature of an emulsion, consisting of small globules, varying from 0.0005 to 0.005 mni- m diameter. It is of variable com- position and may contain certain hydrocarbons, as in pure caoutchouc and pure gutta percha, oils, resins, mucilage, starch, calcium oxalate, and alkaloids. Latex is found in three distinct types of tissues, differing FIG. 127. Study of Latex: A, tangential-longitudinal section through root of Taraxa- cum, showing laticiferous vessel (m), sieve tube (s), parenchyma (p). B, the bark of Euonymus, fractured and showing the thread-like latex (c) between the pieces (b). C, the fragments of thread-like latex of Euonymus viewed under the microscope, and distinguished from fibers by their dissolving in chloroform. — A, after Meyer; C, from drawing by Hogstad. from each other in origin and manner of development, i. Laticif- erous cells are long, tubular cells which arise in the initial cells of the embryo and continue to elongate, keeping pace with the growth of the plant, branching and traversing all of its organs. They may extend through the cells of the pith, bast, and primary cortex, run along the veins of the leaf, being found occasionally in the mesophyll, and extend into the fruit. Cells of this kind 240 A TEXT-BOOK OF BOTANY. are present in the Apocynaceae, Asclepiadaceae, Euphorbiacese, Moraceae, and Urticacese. 2. Laticiferous vessels are long tubes resembling the latex cells, but are formed by the absorption of the transverse walls in the superimposed cells. They develop very early, the cell-fusions taking place, in some instances, in the primary meristems. They may be either. simple or branching, the branches connecting with other tubes and forming a net-work. These anastomosing tubes can be separated readily from the sur- ooo o o FIG. 128. Microscopical appearance of latex in Ficus elastica, showing small globules and sphere-crystals which separate soon after the removal of the fresh latex. — From a draw- ing by Hogstad. rounding tissues by boiling the material with dilute solutions of potassium hydroxide. The laticiferous vessels usually occur as- sociated with the leptome, although they may be found in other tissues of the axis and leaf. Milk vessels are found in the fol- lowing families : Araceae, Campanulacere, Composite, Convol- vulaceoe, Euphorbiaceae, Geraniaceae, Musaceae, Oleaceae,- and Papaveraceae. 3. Secretory cells resembling laticiferous cells, in that they have a latex-like content, although probably of secondary origin, have been found in the Celastraceae, Oleaceae, CELL-CONTENTS AND FORMS OF CELLS. 241 Tiliacese, and Urticacese. The secretion in these cells is some- times visible even with the naked eye, and it is possible, on break- ing the bark, to obtain the latex in the form of delicate, elastic threads. These caoutchouc threads may be readily seen on break- ing the bark of euonymus, and may be distinguished from bast- fibers by their readily dissolving in chloroform (Fig. 127). The milk- juice varies in color in different plants, being color- less, as in oleander ; whitish, as in the Apocynaceae and Asclepiada- ceae ; or yellowish, as in chelidonium, or orange-red, as in sanguinaria. The latex of a number of plants is collected to form a number of commercial products. Opium is the dried milk- juice obtained from the capsules of Papaver somnifenun. Lactucarium is the dried milk- juice of Lactnca virosa and other species of Lactuca. Elastica or India rubber is the prepared milk-juice ob-i tained from a number of plants, the most important being the Brazilian or Para rubber tree (Hevea brasiliensis), the Central American rubber tree (Castilloa elastica), the East Indian rubber tree (Ficus elastica}, and the rubber vines of Africa (Landolphia species). Gutta percha is the concrete juice of Palaquium Gutta (Fam. Sapotaceae). ENZYMES OR FERMENTS. — In connection with the growth of the plant, there occurs a constant change in the substances which comprise it. These changes are brought about largely through the influence of a class of substances known as enzymes. Atten- tion has been directed to the decomposition of starch with the formation of sugar. This change is brought about by the secre- tion in the protoplasm of an enzyme called amylase (diastase). It is produced in the living cell, can be extracted from the plant, and will produce the same effect upon starch grains which have been separated from the cells. One of the interesting properties of the ferments is that in' comparison with the amount of ferment employed the product formed through its influence is very large. Thus it is stated that amylase is able to hydrolyze 10,000 times its own bulk of starch. Results of this kind are considered to be due to catalytic action of the ferments, i.e., their power of inducing chemical reactions by their mere presence without themselves entering into the products formed. The ferments require specific temperatures for 16 242 A TEXT-BOOK OF BOTANY. their action, as, for example, emulsin or sinaptase, which decom- poses a number of the glucosides at a temperature of 35° to 40° C, while amylase, the ferment of germinating seeds, requires a somewhat higher temperature, namely, 50° to 70° C. Another property of these ferments, which is generally re- garded as characteristic of them, is that of becoming inactive when solutions are heated to a temperature of 100° C. Nothing is known with regard to the composition and constitution of the ferments, and they are usually classified according to the class of substances which they decompose. Thus, amylases act upon starch grains with the formation of sugar; proteinases break down the true proteins, etc. The following is an enumeration ot the principal plant enzymes, together with their occurrence and some of their properties : AMYLASE. — The ferment acting upon starch in germinating barley, with the formation of glucose and maltose, was separated by Payen and Persoz in 1833, and called "diastase." This fer- ment occurs, probably, in all parts of all green plants, and is especially abundant in all cells where starch is formed or stored. It is found in large amounts in various cereal grains, and also occurs in the fungi, yeasts, and bacteria. Recent investigation seems to show that in the cells with reserve starches there are two different kinds of diastatic enzymes, the one acting on the soluble starch, called amylase, and the other acting on the insoluble starch or amylopectin, and called amylopectinase. INULINASE is the ferment found in the cells of plants contain- ing inulin. It decomposes the latter, changing it into fruit sugar or fructose. Inulinase has no effect upon starch. It has been found in the Composite and also in Aspergillus, Penicillium, and a number of genera of the Eumycetes. MALTASE (a-glucosidase) is always associated with the diastases, and from which it has not been separated. It is widely found in the vegetable kingdom, and is especially abundant in malt and some of the yeasts. INVERTASE (a-fructosidase), sometimes also spoken of as in- vertin or sucrose, has the property of converting cane sugar into invert sugar (a mixture of glucose and fructose). It is found in CELL-CONTENTS AND FORMS OF CELLS. 243 wheat and barley, dates, bananas, mulberries, and especially in the green leaves and young shoots of higher plants. In yeast it is accompanied in many cases by maltase. EMULSINS are a class of glucoside-resolving enzymes found in the seeds of the almond, the bark of Primus serotina, the leaves of Prunus Laurocerasus, and in a large number of plants of the Rosaceae. It is also found in the tuberous roots of Manihot utilissinia, Monotropa, species of Polygala, Hedera Hclii'. Enzymes resembling emulsins, and capable of attacking gluco- sides, have been detected also in Aspergillus, several species of Polyporus, found growing in wood, lichens, mosses, and bacteria. A distinction is sometimes made between almond-emulsin, Asper- gillus-emulsin, etc. MYROSIN, an enzyme which hydrolyzes the sulphur-glucosides, occurs in the Cruci ferae and in certain species of Manihot. It is localized in the seeds of cells which are rich in proteins. Its presence may also be demonstrated in the mesophyll of young leaves, in the pericycle of stems, and in the cork-cells of roots. GAULTHERASE (Betulase), an enzyme which hydrolyzes the glucoside of methyl salicylate called ' Gaultherin." This is present in Gaultheria and many other of the Ericaceae. It is probably very widely distributed in the vegetable kingdom. (See Amer. Jour. Pharm., 1898, p. 412.) PECTASE AND PECTiNASE.--The name Pectase is applied to an enzyme that is always present in ripening fruit, and is capable of converting pectose, a product insoluble in water, into a soluble substance called pectin. The latter can be further decomposed into a number of closely related substances, known as pectinic acids, and which are usually combined with calcium. The term PECTINASE is applied to the enzymes which in the presence of lime coagulates the juices containing the dissolved pectinous sub- stances forming the so-called fruit jellies. This reaction is con- ditioned on the presence of lime and a certain equilibrium being established between the enzyme and the concentrations of the acid and calcium salts. Pectose originates by reason of certain changes in the lamellae of cell-walls. While it occurs in appreciable quan- tities in those fruits that have the properties of producing jelly, it is probably very widely distributed. 244 A TEXT-BOOK OF BOTANY. CYTASES (cellulases) is the name applied to those enzymes which are capable of dissolving cellulose. An enzyme of this character is located in the aleurone layer and in the epithelium of the scutellum in the germinating grain of barley. It is also found in the endosperm of the date palm, the cytase being formed in the embryo and the dissolved products being used up as food. Enzymes of this character are also found in wood-destroying fungi and bacteria. PROTEINASES (carbamases) is the name applied to those enzymes which break down the true proteins or carbamide deriva- tives. They are always accompanied in the plant cells by other ferments, and occur especially in seeds, being more abundant in those containing oil than starch, as hemp, mustard, castor oil, and flaxseed. They are also found in certain fleshy fruits, as figs and pineapple ; succulent leaves, as Agave, and in insectivo- rous plants. In the fruit and other parts of the papaw tree (Carlca Papaya] occurs a proteolytic enzyme, called Papain, which readily digests -fibrin, thus behaving like trypsin, a ferment in the pan- creatic juice. A similar ferment, called Bromelin, has been ex- tracted from the fleshy pulp of the pineapple. Ferments like Papain and Bromelin are naturally of very great interest, as they behave like the animal ferments, pepsin and trypsin. The Papain of commerce seems to be of varying composition, and unless ob- tained from authentic sources is not reliable. CHYMASES OR ENZYMES which effect the clotting of milk. The coagulating action of the fig ( Ficus Carica) was known to the ancients. This action has been shown by Chodat and Rouge to be due to a vegetable chymase and called by them " sykochymase." A large number of plants possess the property of rendering milk ropy. Of these the following may be mentioned: Ranunculus bulbosus, Capsella Bursa-pastoris, Plantago lanccolata. Medicago lupulina, Pinguicula vulgaris, Artichokes, etc. An enzyme of this character has also been found in germinating seeds of Ricinus communis, Pisum, Datura, etc., and some of the fungi. ZYMASE, an enzyme causing the decomposition of glucose with the formation of alcohol and carbon dioxide. This decomposition, known as alcoholic fermentation, is considerably less simple than was formerly supposed, a number of enzymes and subsidiary sub- CELL-CONTENTS AND FORMS OF CELLS. 245 stances taking part in the reaction. Zymases are widely dis- tributed throughout the entire plant kingdom, and occur in greatest amounts in yeasts and other organisms which induce alcoholic fermentation. The enzyme, which causes the transfor- mation of glucose into lactic acid and is secreted by lactic acid bacteria, has been given the name of " lactic acid bacteria-zymase." OXYDASES is the name applied to those enzymes in which the decomposition or reaction involves an oxidation. Several kinds of oxydases are recognized, depending upon the nature of the original substance that is broken down. ( I ) Alcoholase, the enzyme of acetic bacteria which oxidize ethyl alcohol to acetic acid. (2) Phenolases include the laccases, the oxidizing enzymes found in the lac-tree (Rhns succedanca} , and in some other plants. The black lacquer covering the beautiful Japanese vases and boxes, and which is the most indestructible varnish known to man, is formed by an oxidizing enzyme acting on the phenolic resins of the lac-tree. Catalases in their chemical action resemble some of the col- loidal metals, in that they are able to decompose hydrogen peroxide with the liberation of oxygen. Enzymes of this char- acter have been found in virtually all plant juices. Catalases are of two kinds, one soluble in water, occurring in the seeds of apple and peach, and an insoluble form found in the leaves of clover, rose, and spruce. Highly active catalases are also obtained from fungi, yeasts, and bacteria. While some of the vegetable ferments have been isolated and are prepared on a commercial scale, as diastase and the peptic enzyme papain found in the latex of Carica Papaya, in other cases the ferment-producing organisms themselves are used in a number of industries involving fermentation processes, as the yeast-plants and certain of the molds and bacteria. The microchemical study of the ferments is attended with cer- tain difficulty on account of the lack of specific reagents for their detection. The most that can be done is to study the products formed by their action upon certain other constituents of the cell. (Consult " General Chemistry of the Enzymes," by Hans Euler, translation by Thomas H. Pope.) 246 A TEXT-BOOK OF BOTANY. EXAMINATION OF CELL-CONTENTS PROTOPLASMIC XON-PROTOPLASMIC Crystalline Crystalloidal Amorphous i. Cytoplasm 2. Nucleus 3. Plastids 4. Calcium oxalate 5. Sugars 6. Alkaloids 7. Glucosides 8. Phyto-globulins 9. Starch 10. Inulin ii. Mucilage 12. Tannin 13. Resin 14. Oil 15. Latex 16. Calcium carbonate i, 2, and 3 have characteristic appearance (see Frontispiece). 4. Crystals of characteristic forms, soluble in hydrochloric acid and insoluble in acetic acid. 5. Crystalline in fresh material treated with alcohol. The glucoses give a reddish precipitate with Fehling's solution. 6. Piperine separates in definite crystals in the plant cell ; the alkaloids of hydrastis form crystallizable salts with sulphuric or nitric acids ; the alkaloids in hydrastis, ipecac, coffee, tea, and guarana yield crystalline sublimates. 7. Concen- trated sulphuric acid gives with strophanthin a bright green color. 8. Phyto-globulins form definite crystals (see paragraph on aleurone grains). 9. Blue with dilute iodine solution, except the amylo-dextrin starches, as mace, which are colored red. 10. Sphero-crystals in fresh material treated with alcohol. 1 1. Colored blue with alcoholic solutions of methylene blue. 12. Reddish- brown with copper acetate solutions. 13. Terpene resins are colored green with copper acetate solutions. 14. Separation in the form of large globules on the application of sulphuric acid or solution of hydrated chloral. The volatile oils are more soluble in alcohol than fixed oils, the latter being completely removed from the cells by the use of ether or other similar solvent. 15. Latex occurs as an emulsion consisting of numerous globules. 16. Calcium carbonate dissolves with an effervescence on the addi- tion of hydrochloric acid or acetic acid. Factors Influencing Growth. — Plants have certain inherent or inherited tendencies or characters which make up the inner constitution, and this cannot be modified by external agencies except within more or less narrow limits. Depending upon this character we find plants as different in kind as the apple tree and pine growing under precisely the same conditions. In other CELL-CONTENTS AND FORMS OF CELLS. 247 words, the character of the structure is determined in the main by the nature of the organism. It is true that an apple tree may grow better in one locality than another, but it is still an apple tree whether it be dwarfed or attain to the full measure of its growth. These slight changes in the character are known as accidental variations. Frequently they are the result of tempo- rary conditions and are not repeated in the succeeding genera- tion. On the other hand, if the special conditions remain these individual variations may be repeated in generation after gen- eration and finally become permanent characters. The gradual change in the structure and nature of organisms which takes place through long periods of time is spoken of as EVOLUTION. In some cases specific changes in the characters of plants arise rather suddenly without any known cause, and such changes are spoken of as saltations or MUTATIONS. The factors essential for growth in all cases are food, water, and a certain temperature. Among the food elements we may mention as of chief importance, carbon, hydrogen, oxygen, and nitrogen. Some of the other elements are also essential to most plants, although they occur in relatively small proportion in the plant, as potassium, magnesium, phosphorus, sulphur, iron, and calcium. The latter element does not seem to be necessary to the normal development of some of the Fungi and certain Algae. Water permeates all parts of the plant, and when the cells are in the normal turgescent state it contains more than half its weight of water. When the supply of water falls below the normal the plants begin to droop and finally die. The need of plants varies greatly in this particular ; some are aquatic in their habits and live wholly in the water ; others can live only on the land ; and still others are adapted to desert regions. The degree of temperature necessary for growth varies within certain limits for each kind of plant, but, as is stated by Pfeffer, the greatest extremes are shown by Fungi, Bacteria, and the lower Algae. Generally speaking, the most favorable temperature for growth is between 24° and 34° C. Besides the factors enumerated there are other factors which influence growth. They include light, gravity, mechanical agencies, etc., and are sometimes spoken of as external stimuli. • 248 A TEXT-BOOK OF BOTANY. It is difficult to separate those factors which act solely as external stimuli from those which are essential to the normal growth of the plant and which may be considered as physiological factors. For example, light under certain conditions may be regarded as in the nature of an external stimulus and not essen- tial to the growth of the plant, while in other cases it has a direct influence on normal growth and is essential to the life of the plant, as in all plants or parts of plants where photosynthesis takes place. In addition to the essential food elements, there are many substances which affect the growth of plants which may be grouped as chemical stimuli, such as (a) the substances secreted by gall-forming insects, (b) in a certain measure some of the substances produced by Fungi, (c) and numerous substances not found as normal constituents of the plant. Depending upon the amount of the substance present and the conditions under which it is supplied, the substance may act as a poison and injure the plant, or it may accelerate growth, or cause abnormal develop- ment. This subject has an important bearing on the physiological testing of drugs. Robert states that in determining the qualities of a new chemical, preliminary experiments should be conducted on lower plants and animals before trying it on man. Of the plants which have been used in the testing of poisons the follow- ing may be mentioned : Oscillaria, Spirulina, Nostoc, Zygnema, Spirogyra, Saccharomyces, Mucor, Elodea, Lemna, Pistia, Potamogeton, Myriophyllum, Ceratophyllum, Tradescantia, seed- lings of grasses, lupine, bean, pea, corn, etc. Kraemer has em- ployed seedlings of Lupinus albus and Pisum sativum in testing solutions containing ethyl alcohol, strychnine nitrate, brucine sulphate, and tincture of mix vomica (Amcr. Jour. Phann., 1900, p. 472). FOOD OF PLANTS. — It has already been pointed out that certain of the chemical elements are necessary for the growth of plants, and that these are derived partly from the surrounding atmos- phere and partly from the soil. Those elements derived from the air are either themselves gases or exist in combination in the form of gas, and include oxygen, nitrogen in exceptional cases, CELL-CONTENTS AND FORMS OF CELLS. 249 and carbon dioxide, the source of the carbon entering into the carbon compounds formed by plants. The elements obtained by plants from the soil exist in com- bination with other elements and must be in the form of solution to be absorbed. The soil consists largely of mineral substances, together with certain organic products (humus). The water held in the soil not only acts as a medium for carrying the soluble constituents in the soil to the plant, but is itself an important food product, being the source of the hydrogen used by plants, as also of assimilable oxygen. Among the mineral constituents of the soil that are useful to plants are ammonium salts and nitrates, sulphates, phosphates, chlorides, silicates, and carbonates. When plants are collected and subjected to a temperature of about 110° C. the water is driven off, and then if heat sufficient to incinerate the material is applied the organic matter is driven off in the form of gases, leaving the mineral constituents in the form of ash, as calcium, magnesium, iron, potassium, sodium, and a few other elements. FORMATION OF LEAFMOLD. — When the leaves of a tree fall to the ground they begin to decay and ultimately they are dis- integrated, and their substances become incorporated with the other elements of the soil. The same thing happens with the leaves, stems, and roots of herbaceous plants. Such organic matter is one of the chief sources of food for plants, and its presence in the soil is therefore of fundamental importance in the maintenance of the vegetable mantle of the earth. Coville (Jour. Wash. Acad. ScL, 1913, p. 79) determined the rate in decomposi- tion of leaves and used silver maple, sugar maple, red oak, and Virginia pine. These were exposed to the weather in barrels and in concrete pits. In one experiment a mass of trodden silver maple leaves two feet in depth, with an initial acidity of 0.92 normal, was reduced in a single year to a three-inch layer of black mold containing only a few fragments of leaf skeletons and giving an alkaline reaction. Sugar maple leaves have shown a slower rate of decomposition than those of silver maple, while red oak leaves still showed an acidity of o.oio normal after three years' exposure, and leaves of Virginia pine an acidity of 0.055 normal under the same conditions. During the decomposition of 250 A TEXT-BOOK OF BOTAXY. leaves the acid substances are decomposed and to some extent dissipated in the form of gases. The chief agents in the decay of leaves are fungi and bacteria. A number of forms of animal life also contribute greatly to the decay also, as earthworms, larvae, flies and beetles and myriapods or thousand-legged worms. Coville distinguishes two kinds of leafmold : (a) In which the leaves show a condition of imperfect decomposition, due to the development and maintenance of an acid condition, which is inimical to the growth of microorganisms of decay. Because of the resemblance of this mat or turf to bog peat in appearance, structure, and chemical composition, and be- cause it supports a type of vegetation similar to that of bog peat, it has been named UPLAND PEAT. This is characteristic of the sandy pine and oak woods, where grow huckleberries, laurel, princess bine, pink lady's slipper, trailing arbutus, etc. (£>) The other is characteristic of the black mellow mold made up of com- pletely rotted leaves, the acidity being neutralized in part by the calcium present in the leaves and partly by the underlying soil, which is usually of a calcareous nature. This is characteristic of forests of tulip poplar, ash, and oaks, in which grow sanguinaria, caulophyllum, hydrastis, trillium, etc. ORGANIC CONSTITUENTS IN SOIL. — During the past few years Schreiner and his associates in the Bureau of Soils, U. S. Depart- ment of Agriculture, have isolated and identified a number of soil constituents. They have found that certain of these con- stituents, as dihydroxystearic acid, are rather characteristic of poor soils, and that the effect of fertilizers on such soils was to increase their fertility by neutralizing their toxic constituents rather than by the addition of any food constituents to the soil. The compounds isolated by them have varied considerably, and may be grouped into the following classes : I , Paraffin hydro- carbons, represented by hentriacontane ; 2, hydroxy-fatty acids, represented by a-monohydroxystearic acid and dihydroxy- stearic acid ; 3, organic acids of unknown constitution, represented by agroceric acid, paraffinic acid, lignoceric acid, and a number of resin acids ; 4, esters and alcohols, represented by agrosterol, phy- tosterol, glycerides of fatty acids, and resin esters; 5, carbohy- drates, represented by pentosans and pentose sugars ; 6, hexone CELL-COXTEXTS AXD FORMS OF CELLS. 251 bases, represented by histidine and arginine ; 7, pyrimidine deriva- tives, represented by cytosine ; 8, purine bases, represented by xanthine and hypoxanthine ; 9, pyridine derivatives, represented by picoline carboxylic acid. ROOT ABSORPTION. — Notwithstanding the various agents which are at work tending to break down and dissolve the sub- stances contained in the soil, as soil bacteria, the liquids given to the soil by the roots of the plants themselves, the presence of the so-called humic acids, and the action of water and air, it has been shown that the soil water is an exceedingly weak solution. This is largely due to the peculiar absorptive and fixing power of the soil itself. The dilution of the aqueous solution of the soil constituents is a matter of very great significance, for upon this depends its absorption by the root hairs. While other parts of roots have cer- tain absorptive powers, the root hairs have been defined as the organs of absorption of the plant. They are very delicate in structure and contain protoplasm. Their absorbent function de- pends upon the principle that when a membrane (animal or vegetable) is interposed between two liquids of unequal density, the less dense liquid will pass through the membrane and mix with the denser liquid. This process is known as OSMOSIS, and when a liquid passes outward through a membrane or cell-wall it is called exosmosis, and when inward it is called endosmosis. The soil is made up of minute earth particles, each of which is surrounded by a thin film or envelope of water, and it is this por- tion of the soil liquid that is absorbed by the root hairs. The root hairs come into close contact with these soil particles ; in fact, appear to grow fast to them, and the cell-liquid in the root hairs being denser than that surrounding the soil particles, the latter passes through the wall into the root hairs. If, on the other hand, the water supplied to the roots of plants should contain an excess of soluble material, the plant will be injured. In this case exosmosis ensues and the plant loses some of its own liquids or cell-sap and will show signs of wilting. It is well known that if cultivated plants are supplied with strong solutions of fertilizer the plants will be injured rather than benefited. 252 A TEXT-BOOK OF BOTANY. ROOT PRESSURE.- -The distribution of the water absorbed by the roots to other parts of the plant is influenced by a number of factors, which are commonly spoken of together as root pressure. Among these are osmosis within the plant, due to unequal density of the liquids in different cells; the changes in the equilibrium of the cell-liquids, due to chemical changes ; and the transpiration of water from the leaves, thus establishing a flow of liquids from the roots upward, which is usually spoken of as the ASCENT OF SAP. The cell-sap passes upward through the xylem for the most part, carrying constituents obtained from the soil to the growing parts, where they are combined with the products of photosyn- thesis, and through a series of reactions protoplasm is finally built up. OXIDATION. — The free oxygen taken in by plants through the stomata and lenticels serves the same purpose in plants as that inhaled by animals, namely, the oxidation of certain compounds, whereby part of the energy necessary for vital activity is lib- erated. Oxygen is required by all parts of the plant. When the roots of plants, such as those of Zea Mays, are surrounded by water so as to exclude the air the plants will become yellow. Germinating seeds consume a large amount of oxygen, but not all the energy formed is used by the plantlet, much of it escaping as heat, as in the germination of barley in the preparation of malt. Those plants dependent upon the presence of free atmospheric oxygen are called AEROBES, while those which are not thus de- oendent, as certain fungi and bacteria, are called ANAEROBES. METABOLISM. — Processes of construction and destruction are going on simultaneously in the plant, and these are all grouped under the general name of metabolism. The processes whereby complex substances are built up from simpler ones, as in photo- synthesis, are together spoken of as CONSTRUCTIVE METABOLISM (anabolism), while those which involve the breaking down of complex compounds into simpler ones, either through oxidation or other chemical action, as when sugar is changed into carbon dioxide and water, are grouped under the head of DESTRUCTIVE METABOLISM (catabolism) . Inasmuch as the carbon dioxide of the atmosphere and the water taken up by the roots together with the mineral salts which CELL-CONTENTS AND FORMS OF CELLS. 253 it holds in solution are the only sources of the food supply of green plants, it follows that the highly complex proteins trace their origin to these comparatively simple substances. By some it is supposed that the final stages in the building up or synthesis of the proteins take place in the leaves; but it is probable that they take place in all the growing parts of the plant. It has already been stated in the paragraph on proteins that seeds contain re- serve materials which are broken up into simpler compounds through the action of certain enzymes, and thus made available for the seedling. It is claimed that these compounds .are prin- cipally amino acids, and that of these aspartic and glutaminic acids occur in largest amount and that these two acids are found in different relative amounts in different plants. It is furthermore claimed by some authors that by certain syntheses these com- pounds are respectively converted into asparagin and glutamin, both of which occur as reserve materials in seeds and in other parts of plants as well. Yet other syntheses take place whereby asparagin and similar bodies are converted into albumin and other proteins. In the Coniferae the part played by asparagin and glutamin in protein syntheses is taken by arginin, which substance is found in considerable amount in the seeds of the plants of this group. GROWING POINTS AND MERISTEMS. — Plants are distinguished, for the most part, by having distinct growing points, known as vegetative points. These occur at the apex of shoots and roots and at definite lateral points, being in the stem near the surface and in roots beneath the endodermis. The walls of the cells in these regions are very thin and consist almost entirely of cellulose. The cells are compactly arranged and are more or less polygonal Or somewhat elongated. They are rich in protoplasm, capable of rapid division, and constitute the tissue known as PRIMARY MERI- STEM. In the root three kinds of primary meristem (Fig. 132) are distinguished: (i) The PLEROME (m, f, g), an axial meri- stem, which gives rise to the central cylinder or stele; (2) the PERIBLEM (x, r), or meristematic tissue, which gives rise to the primary cortex; and (3) the DERMATOGEN (e), from which the epidermis is developed. In addition to these three meristematic zones there is at the apex, lying next to the dermatogen, a meri- 254 A TEXT-BOOK OF BOTANY. stematic group of cells which give rise to the root-cap, known as the CALYTROGEN (s). At the growing point of the stem three meristematic zones are also distinguished, namely, plerome, periblem, and dermatogen. They are not, however, so well marked as in the case of roots. The tissues which are developed from the primary meristems constitute the PRIMARY STRUCTURE. With the growth in thickness of the stems and roots of Dicotyledons other meristematic cells, known as SECONDARY MERISTEMS, arise. These are of two kinds : ( i ) One which gives rise to the xylem and phloem, known as the CAMBIUM, and (2) another which gives rise to the cork, known as PHELLOGEN. The tissues formed from the secondary meristems constitute the SECONDARY STRUCTURE of older dicotyledonous stems and roots. While the point of vegetation in the higher plants (spermo- phytes) embraces a number of cells, in the lower plants the tissues can be traced back to a single APICAL CELL. CELL-WALL. — Origin and Composition. — It is formed by the protoplasm, and varies in composition at different stages of the growth of the cell, and according to the various functions it has to perform. In order to thoroughly understand the nature and composi- tion of the cell-wall, it is necessary to study the origin and forma- tion of new cells. Growth of the plant is attended not only by an increase in the size of the cells, but by their division (Fig. 85) new cells are also formed. Cells that have the property to divide and form new cells are known as meristematic cells and constitute the MERISTEM. The new and dividing walls resulting from the division of the cells consist of a number of substances. When a cell divides, the two daughter protoplasts which result from the division of the nucleus and cytoplasm are separated by the forma- tion of a new wall between them (Fig. 85). The first layer formed is apparently different from the subsequent layers and is known as the middle plate or MIDDLE LAMELLA. This layer is soluble in, or readily attacked by, solutions of the alkalies or solu- tions containing free chlorine. It is insoluble in sulphuric acid, and readily stained by the aniline dyes. While usually more or less permanent, this middle plate may be finally absorbed, as in CELL-CONTENTS AND FORMS OF CELLS. 255 the glandular hairs of kamala, or it may be changed into mucilage, as in chondrus, or transformed into pectin compounds, as in fleshy roots and fruits. To this middle plate is added on either side by the newly formed protoplasts a layer of substance closely resembling cellu- lose, this constituting the PRIMARY MEMBRANE or primary lamella. As the cells become older the wall increases in thickness through the addition of other layers, much in the same manner as the starch grain increases in size. These subsequent layers are known as SECONDARY LAMELLAE. In a few cells the secondary lamellae may consist of pure cellulose. As a rule, however, the wall is rather complex and consists of alternate layers of cellulose with other substances. Some of these, as mucilage, may be a simple modification of cellulose, others may consist of cellulose in combination with other substances, as in the ligno-cellulose walls of stone cells, or the walls may consist of cellulose and suberin as in cork cells, or of cutin-cellulose as in epidermal cells. Again, there may be, through the action of special enzymes, a decomposi- tion of the cellulose, resulting in the formation of oils, resin, and wax. Furthermore, it would not seem improbable that some of the secondary substances in the \vall are direct products of the protoplasm and secreted in the cell-wall, as silica and calcium oxalate in epidermal cells. The substance called pectin originates as a modification of the intercellular substance, and is peculiar to some fruits. As showing, to some extent, the complexity of the lamellae in the cell-wall, the following modifications of the wall in secretion cells may be given: I. The entire outer cell-wall may consist of a thin layer of suberized lamellae, beneath which is a secondary mucilaginous layer that develps the secretion, e.g., Hedychium Gardnerianum. 2. The outer lamellae of the cell-wall may con- sist of suberin ; beneath this is a cellulose lamellae, which only after treatment with a solution of potassium hydroxide is colored blue with chlor-zinc iodide ; this is followed by a mucilaginous layer, e.g., Laurus nobilis. Curcuma Zcdoaria, Cinnamomum Cas- sia, Zingiber officinale, Ac or us Calamus. 3. The outer layer may consist of cork, beneath which is a cellulose layer that is colored blue upon treatment with chlor-zinc iodide without the previous 256 A TEXT-BOOK OF BOTANY. use of potassium hydroxide ; to this is then added a mucilaginous layer, as in the secretion cells of Valcriana officinalis and Magnolia grandiflora. 4. The outer layer may be suberized, but the cellulose layer beneath this is not colored blue until the walls have been first treated with Schultze's solution ; this then is followed by a mucilaginous layer, e.g., Piper nig nun. Piper Cnbeba, and Sassa- fras officinale. 5. The outer and inner layers may be suberized, and between these are fine lamellae of cellulose, e.g., Croton Eluteria. 6. The outer layer may be suberized, beneath which is a layer of lignocellulose, followed by a mucilaginous layer, e.g., Calycanthns florid us. 7. The outer layer may be colored yellow with chlor-zinc iodide and dissolves in sulphuric acid, while the inner layer is suberized, e.g., fruit of Coniuui maculatum. CELLULOSE in its various modifications constitutes the greater proportion of the cell-wall. The cellulose making up the cotton fiber may be said to be the typical cellulose, and is known as ' cotton cellulose." It is soluble in copper ammonium sulphate solution ; is colored blue with chlor-zinc-iodide solution or iodine and sulphuric acid, and is stained by acid phenolic dyes, as alizarin, if previously treated with basic mordants, as basic salts of aluminum, etc. The following solutions are used in the testing of mixed fabrics containing cotton : I. A solution of I part of zinc chloride in 2 parts of hydrochloric acid will dissolve cellulose in about one-half minute. 2. Upon heating a piece of fabric in a saturated solution of aluminum chloride, the cotton becomes friable, the wool remaining unaffected. According to their origin in the plant, or their behavior toward reagents, the cellulose walls may be divided into the following groups: (i) Lignocellulose walls; (2) protective cellulose walls; (3) reserve cellulose walls; (4) mucilage cellulose \valls, and (5) mineral cellulose walls. Lignocellulose walls are composed of true cellulose and a non-cellulose (the so-called lignin or lignone), these constituting the woody (so-called lignified) portion of plants and, in some instances, also the bast portion of the bark. The lignocelluloses are colored yellow with chlor-zinc iodide, or iodine and sulphuric acid. On account of their containing in some instances furfurol, CELL-CONTENTS AND FORMS OF CELLS. 257 coniferin, vanillin, cinnamic aldehyde, benzaldehyde or other alde- hydic substances, they give definite color-reactions .with certain reagents. They are also stained by the aniline dyes, as fuchsin, safranin, gentian violet, aniline blue, methylene blue, etc. Aniline hydrochloride with hydrochloric acid and aniline sul- phate with sulphuric acid produce a golden-yellow color in cell- walls containing lignocelluloses. A 2 per cent, phloroglucin solution, used in conjunction with hydrochloric acid, gives a reddish-violet color with the lignocellu- loses, although there are some celluloses of this class which do not respond to this test, as flax (the bast fibers of Linum). In other plants phloroglucin may occur as a constituent of the cells. Hartwich and Winckel (Arch. d. Phann., 1904, p. 462) have shown that the red coloration formed upon the addition of vanillin and hydrochloric acid to phloroglucin is also produced by a number of other substances, viz., thymol, guaiacol, resorcin, cresorcin, orcin, pyrogallol, pyrogallol dimethyl-ether, phloroglucin, oxy- hydroquinone, eugenol,-and safrol, but not with phenol, pyro- catechin, hydroquinone, or pyrogallol trimethyl-ether. The re- action cannot, therefore, be longer designated as a phloroglucin reaction, but, in a limited sense, as a phenol reaction. The same color reaction is produced by a number of other substances which contain a phloroglucin molecule, e.g., phloridzin, maclurin, luteolin, morin, catechin, filizin, gentisin, and all the phloroglycotannoides, as in oak bark and cinchona bark. Protective cellulose walls are composed of mixtures of lig- nocellulose and oils and waxes, and frequently contain in addi- tion tannin, vanillin, and other compounds. In the cuticle or epi- dermis of leaves and green stems the cellulose is associated with a fatty compound known as cutin (or cutose), while in the cork of stems and roots it is combined with suberin (or suberose). This class of celluloses is distinguished from cotton cellulose and lignocellulose by being insoluble in sulphuric acid. Reserve cellulose walls are those found in various seeds, as in coffee, date, nux vomica, etc. They behave toward reagents much like the true celluloses (Fig. 135). Mucilage cellulose walls consist of cellulose and mucilage, and are found in all parts of the plant, and in the case of seeds 17 '258 A TEXT-BOOK OF BOTANY. are associated with the protective celluloses. They dissolve or swell in water, are colored blue (as in flaxseed) or yellowish with iodine, and are stained with alcoholic or glycerin solutions of methylene blue. Mineral cellulose walls are composed of cellulose and vari- ous inorganic substances, as silica, calcium oxalate, or calcium carbonate. These are more commonly found in the cell-wall of the lower plants, as Algae, Fungi, and Equisetaceae. Calcium car- bonate and silica also occur in the cystoliths of the various genera of the Moraceae and Acanthaceae (Fig. 113). From what has just been said of the chemical composition and structure of the cell-wall, it is seen that it consists of lamellae or FIG. 129. i, cross-section of a bast fiber of Begonia as seen by means of the micro- polariscope, and showing stratification of the wall. 2, polariscopic view of a sphere-crystal of inulin in Helianthus tuberosus. — After Dippel. layers of different substances, and in no case does it consist of but a single substance; but for convenience we speak of a .wall as consisting of cellulose, lignin, or suberin, meaning thereby that the wall gives characteristic reactions for these substances. PHYTOMELANE, an intercellular, carbon-like substance. It is a black, structureless substance, found only in the Compositae, being distributed around the sclerenchymatous fibers and stone cells in a number of fruits. It has also been found in the lignified cells of roots and stems (Fig. 131), and occasionally is found in the parenchyma cells of Inula. In the latter it occurs more or less crystalline, sometimes in the form of short needles or rods (Fig. 132). According to Hanausek (" Untersuchungen iiber die Kohleahnliche Masse der Kompositen ") , phytomelane occurs in a large number of genera in the Compositae. It arises in the middle lamellae and has a high content in carbon, ranging from 69.76 per CELL-CONTENTS AND FORMS OE CELLS. 259 cent, in Helianthus annuus to 76.47 per cent, in Dahlia variabilis. It is unaffected by most reagents except hydriodic acid. It may readily be separated in unaltered masses upon treatment of the tissues with Wiesner's chromic acid mixture or with Schultze's macerating solution. Hanausek considers the phytomelane layer to be in the nature of a mechanical protection to those fruits and seeds in which the epidermal and hypodermal layers scale off with the ripening of the fruit. (Consult Kraemer and Sollenberger, Aincr. Wti m \ FIG. 130. Striation in cell-wall: I, a portion of bast fiber in Oleander, showing left spiral bands as seen from the outer surface (a) and the same as seen from the inner surface (b); II, portion of the bast cell of Asdepias syriaca as seen on the under surface; III, a view of the bast fiber of Asdepias syriaca as seen when looking through the middle of the cell; IV, portion of tracheid of Finns sylvestris, showing two views of the striations of the wall. — After Dippel in "Das Mikroskop." Jour. Pharm., 1911, p. 315; Senft, Pharm. Post, 1914, No. 30; Hanausek, Bcr. d. d. hot. Ges., 1911, p. 558.) LAMELLAE. — In some cells, as in lignified cells, the lamellae are quite apparent. In other cases the use of reagents, as chromic acid or chlor-zinc iodide, is necessary to bring out this structure. The layering which is observed in transverse sections of the cell- wall is spoken of as stratification of the wall (Fig. 129), whereas the layering observed in longitudinal or tangential sections is referred to as striation of the wall (Fig. 130). 260 A TEXT-BOOK OF BOTANY. Thickening or Marking of Walls. — In the formation of the wall each cell appears to work in unison with its neighbors for the building up of the plant. The thickening of the walls of the cell is primarily for the purpose of strengthening the walls, but if the walls were uniformly thickened, osmosis, or the trans- ferral of cell-sap from one cell to another, would be hindered. FIG. 131 . Phytomelane, an intercellular carbon-like substance occurring on the outer layers of the stone cells in Brauneria pallida (Echinacea angustifolia), Thus we find that the contiguous walls of the cells are thickened at definite places opposite each other, leaving pores or canals which permit rapid osmosis. The pores thus formed are known as simple pores, and when seen in surface view are somewhat elliptical or circular in outline, and may be mistaken for some of CELL-CONTENTS AND FORMS OF CELLS. 261 the cell-contents. These thickenings assume a number of forms, which are quite characteristic for the plants in which they are found. They may have the form of transverse or oblique rings. FIG. 132. Phytomelane in root of Inula Helenium. 1-3 showing intercellular spaces with carbon-like substance; 4-8, striated structure of intercellular phytomelane in sections which have been allowed to remain in solutions of hydrated chloral or potassium hydrate for some days; 9, a large crystal-like aggregate in a schizogenous-like reservoir formed in contiguous intercellular spaces of 5 parenchyma cells; 10, separated crystal-aggregates and rod-shaped masses of Phytomelane. — After Senft. longitudinal spirals, or may be ladder-like or reticulate in appear- ance (Figs. 141-144). In other instances the thickening of the wall is quite complex, as in the wood of the pines and other Conif- ers (Fig. 68). The thickening, or sculpturing, as it is sometimes 262 A TEXT-BOOK OF BOTANY. called, may not only occur on the inner surface of the wall, when it is spoken of as CENTRIPETAL, but may also take place on the outer surface, when it is known as CENTRIFUGAL, as in the spores of lycopodium and the pollen grains of the Compositae. FORMS OF CELLS. Upon examining sections of various portions of the plant, it is observed that not only do the cell-contents and cell-wall vary in composition, but that the cells are of different forms, depend- ing more or less upon their functions. Groups of cells which are similar in form and function constitute the various tissues of the plant; and include: (i) parenchyma cells, (2) mechanical cells, (3) conducting cells, and (4) protective cells. Parenchyma. — Under the head of parenchyma are included those cells which are nearly isodiametric and thin-walled, the walls consisting of cellulose lamellae (Fig. 134). They may contain both protoplasmic and non-protoplasmic cell-contents. Accord- ing to the function and nature of contents, five kinds of paren- chyma cells are recognized : (a) CHLOROPHYLL-PARENCHYMA or assimilation parenchyma contains numerous chloroplastids and occurs in leaves and all green parts of the plant, (b) RESERVE PARENCHYMA occurs in seeds, roots, rhizomes, leaves, and contains starch, aleurone grains, fixed oils, and other reserve materials. In some instances the parenchyma, as in the endosperm of date, ivory nut, etc., may be very thick- walled (Fig. 135). The paren- chyma in stems and leaves of various of the orchids, as well as that of plants of arid regions, which store water, may be included in this group, (c) CONDUCTING PARENCHYMA is found either associated with the sieve or with the tracheae, the cells of the phloem conveying the plastic substances, while those of the xylem convey water and salts. The cells of the pith and cortex are, as a rule, not utilized for the rapid translocation of food materials to far distant parts, although every living cell and every tissue has a certain power of translocation, and no doubt different parenchymatous tissues exhibit varying degrees of functional activity and differentiation. Thus large quantities of reserve materials are rapidly transferred to the developing embryo through the cells of the endosperm, and in young seedlings further trans- CELL-CONTENTS AND FORMS OF CELLS. 263 ference probably takes place mainly through the cortical and medullary parenchyma, (d) SPONGY PARENCHYMA, or loose, spongy tissue with large intercellular spaces. The cells of this J// A FIG. 133. A cei] from sassafras pith showing intercellular space (i); middle lamella (m); layer of lignin (1); and layer of cellulose (c), which is subsequently modified to muci- lage; simple pores (p) which are seen in the lower wall, the section being slightly oblique. B, portion of wall showing the appearance of the pores when the view is transverse to the wall and the focus is at the upper part of the pore (a) or at the lower part (b). type vary from slightly branched cells, as in the mesophyll of leaves, to those which are strongly branched and stellate, as in Juncus, Pondederia, and the stems of various marsh plants. In 264 A TEXT-BOOK OF BOTANY. Calamus the cells are so arranged that very large intercellular spaces are formed (Fig. 134). (e) A number of modifications of typical parenchyma also occur, some of the cells being either quite thick-walled or considerably elongated. The walls of pith- 0 FIG. 134. Forms of cells. A. — Transverse section of the pith of Tradescantia vtr- ginica: I, intercellular space; W, cell wall. B. — Transverse section of calamus rhizome showing a large oil-secretion cell, smaller cells containing starch, and large intercellular spaces (I). C. — Transverse section of the stem of Phytolacca decandra showing collenchy- matous cells beneath the epidermis. D. — Longitudinal section of taraxacum root showing branched laticiferous tissue (L). E. — Transverse section of pyrethrum root: R, oil-secre- tion reservoir with oil globules; I, cells with sphere-crystals of inulin, such as separate in alcoholic material; L, cells containing irregular masses of inulin, as found in dried material. F. — Longitudinal section of stem of Cucurbita Pepo: S, sieve-cell with protoplasm-like contents, and transverse walls (sieve plates) showing simple pores. parenchyma may consist of lamellae of lignocellulose and mucilage, as in Sassafras pith (Fig. 133). MECHANICAL TISSUE includes all those cells which serve to keep the various parts of the plant in their proper positions, one CELL-CONTENTS AND FORMS OF CELLS. 265 with reference to the other, and which enable it to withstand undue strain and pressure. There are two principal forms, namely, (a) collenchyma and (b) sclerenchyma. THE COLLENCHYMA CELL is elongated, prismatic, with soft FIG. 135. A, cells of endosperm of the seed of the date palm (Phoenix dactylifera) , the one normal and the other showing the stratification of the wall after treatment with chlor-zinc-iodide. B, cell of endosperm of Phytelephas macrocarpa (vegetable ivory) showing lamellation and spherite structure in the wall after treatment with chlor-zinc-iodide, clove oil, chromic acid or certain other reagents. C, cell of endosperm of Strychnos Nux-vomica after treatment with iodine and potas- sium iodide solution. D, opposite pores in the walls in contiguous cells of vegetable ivory showing striae between them after treatment with iodine solution. walls consisting mainly of cellulose and never lignified ; the contents being rich in water. In transverse section it is readily distin- guished by the local thickening of the walls, i.e., at the angles of 266 A TEXT-BOOK OF BOTANY. the cells (Fig. 134, c). Pores are rare, but when present they are annular or slit-like. Collenchyma occurs near the surface of plant organs, as herbaceous stems, when they form ribs, as FIG. 136. Various forms of stone cells: A, epidermis of hyoscyamus seeds; B, pericarp of pimenta, containing brownish tannin masses; C, seed-coat of coffee; D, seed-coat of almond; E, transverse section of seed-coat of white mustard showing beaker cells; F, surface view of beaker cells of seed-coat of white mustard; G, transverse section through stone cells of endocarp of olive, the lumen containing air; H, a stone cell from the periderm of calumba, containing numerous monoclinic prisms of calcium oxalate; I, various forms of stone cells isolated from pericarp of star anise. in the Umbelliferae. It is also found in leaves and in fruits, as in the Umbelliferae. SCLERENCHYMA CELLS include all of those cells which have more or less uniformly thickened walls composed of lignocellulose, CELL-CONTENTS AND FORMS OF CELLS. 267 permeated by simple or branching pores. They have a thin layer of protoplasm enclosing large vacuoles, and may contain tannin or tannin-like masses, and occasionally calcium oxalate crystals or starch, and in dead cells the lumen or cell cavity contains air. Two kinds of sclerenchyma are recognized: i, in which the cells are more or less isodiametric (Figs. 136-138), known as stone cells (short sclerenchyma) ; and 2, in which the cells are elongated (Figs. 139-141), being from 0.5 to 2 mm. in length and known as sclerenchymatous fibers (or long scleren- chyma). Of these latter, two kinds are distinguished, chiefly according to their position in the plant, namely, bast fibers, or stereome, and wood fibers, or libriform. Seldom are the wood and C FIG. 137. Several forms of stone cells: A, white oak bark; B, white cinnamon or canella bark (Canella alba); C, seed-coat of capsicum. bast fibers in the same plant uniform in structure and composition, as in glycyrrhiza and althaea. On the other hand, they are with difficulty distinguished in monocotyledonous roots, and the term sclerenchymatous fiber is here best employed to include both kinds of cells. In the study of powdered drugs the term sclerenchyma- tous fiber may be employed with advantage when speaking of wood and bast fibers, as in this condition they are not readily distinguish- able. It is usual in plant anatomy to include as stereome all ligni- fied fibers not directly associated with the vessels of the mestome strands (or vascular bundles). STONE CELLS or SCLEROTIC CELLS are parenchymatous cells with very thick, lignified walls, composed of numerous lamellae, 268 A TEXT-BOOK OF BOTANY. which are permeated with simple and not infrequently branching pores. They vary in form, being usually polygonal, or more or less irregular in outline, sometimes branching. The lamellation of the walls is brought out by the use of swelling reagents, as solu- tions of the alkalies, hydrated chloral, chromic acid, etc. In typical stone cells the walls always give the characteristic re- action for lignocellulose with acid solutions of either phloro- glucin or aniline sulphate. The lumina of the cells frequently contains a reddish, amorphous substance, seldom are crystals of calcium oxalate present (Fig. 136, //), and not infrequently they are filled with air (Fig. 136, G). In the identification of com- FIG. 138. Various forms of stone cells in star anise, the fruit of Ilhcium anisatum. mercial products the study of the contents of the stone cells is frequently as important as that of the forms of cells. BAST FIBERS or STEREOMATIC CELLS are sclerenchymatous fibers, occurring in the bark and usually associated with sieve cells. They represent the skeleton of plants and are the most important mechanical tissues of the bark, being much firmer than the collen- chyma. They are very long, spindle-shaped, with more or less thick walls, and provided with slit-like, oblique pores. The walls may consist of cellulose, as in the fibers of flax, but they are usually more or less lignified ; the lumina is narrow and usually contains air. In transverse sections the fibers are more or less CELL-CONTENTS AND FORMS OF CELLS. 269 circular, ellipsoidal or polygonal, depending upon the pressure upon the walls and whether they are isolated or in groups. They vary in diameter and length, and also in the thickness of the walls ; while most bast fibers are between I and 2 mm. in length, they may be more than 200 mm. in length, as in Bochmcria nhca. The ends may be more or less obtuse or drawn out to a fine point ; FIG. 139. Transverse (t) and longitudinal (1) sections of commercial fibers: A, long staple cotton from the seeds of Gossypium; B, Kentucky hemp, the bast of Cannabis sativa; C. jute, the bast of Corchorus; D, sisal, the fibers from the leaves of the Century plant (Agave rigida Sisalana} ; E, raphia, the outer layers of leaflets of Raphia pedunculata; F, ramie, the fibers from a Formosa nettle; G, Merino wool; H, silk; I, artificial silk, the figure on the left showing a false lumen due to the infolding of the edges, f , fungal hyphae; c, rosette aggregates of calcium oxalate; p, parenchyma cells. occasionally they are somewhat branched (Fig. 140). The pores in surface view are narrow elliptical and arranged according to a left-handed spiral. The spiral arrangement of the component elements of the wall is supposed to give strength to the fibers, and, according to Schwendener, they will sustain a weight nearly equivalent to that of wrought-iron and steel. 27O A TEXT-BOOK OF BOTANY. Bast fibers may be isolated by the use of Schulze's macerating fluid (which is prepared by dissolving a few crystals of potassium chlorate in nitric acid) and moderately heating the solution con- taining the material either on a slide or in a test-tube. The mechanical tissue consisting of cells resembling bast fibers and occurring in leaves and fruits is usually referred to as stereome. WOOD FIBERS or LIBRIFORM CELLS are sclerenchymatous fibers A 8 r I ( / \ ) \ ' FIG. 140. A, C, bast fibers of the bark of Cinchona succimbra; B, bast fibers of the bark of Cinchona Ledger iana; D, stone cells of Cuprea bark (Remijia peduncuiata). — After Oesterle and Tschirch. occurring in the wood and are usually associated with the tracheae. They are scarcely to be distinguished from the bast fibers except by their position, and are the strengthening cells of the xylem. While the bast fiber is frequently not lignified, the walls of the wood fibers usually consist of lignocellulose, and usually give quite pronounced color reactions with acid solutions of either phloroglucin or aniline sulphate. Wood fibers are usually more CELL-CONTENTS AND FORMS OF CELLS. 271 abundant than bast fibers in the same plant, and, while the bast fibers may be wanting, the wood fibers, with few exceptions, are always present. Wood fibers seldom attain the length of bast WF '.'«"' * * ' CF BF FIG. 141. Longitudinal-transverse section of licorice rhizome including the cambium: P, parenchyma; T, tracheae or ducts; WF, wood fibers; C, cambium; S, sieve; CF, crystal fibers; BF, bast fibers; MR, medullary ray. fibers. They are not infrequently branched at the ends, and, besides a thin protoplasmic layer, they usually have no other contents than water or air. They frequently have yellowish walls, characteristic of stone cells, and also exhibit a similar lamellation and refraction of the wall. 272 A TEXT-BOOK OF BOTANY. Conducting cells or mestome include those cells which are chiefly concerned in the transferral of either crude or assimilable FIG. 142. Development of spiral bands in the mechanical cells of young fruits of Fegatella conica (Hepaticae) : I, young cell with vacuoles and small starch grains; II, portion of an older cell showing formation of large vacuoles in the protoplasm, the strands of which are arranged in a left-hand spiral; III, showing spiral arrangement of protoplasm; IV, portion of cell as in III treated with a sugar solution and showing plasmolysis of protoplast; V, showing formation of band; VI, a cell as in V treated with sugar solution, showing the protoplasm arranged along the thickened portions of the wall where the bands are forming; VII, the mature cell showing lignified spiral bands. — After Dippel in "Das Mikroskop." food materials. The more or less crude inorganic materials are carried from the root through the woody portion of the stem to CELL-CONTENTS AND FORMS OF CELLS. 273 the leaves, and from the leaves the products of photosynthesis, as well as other plastic substances, are distributed through some of the tissues of the bark to other parts of the plant. The tissues or elements of the wood which conduct food materials are of sev- eral forms and include tracheae or vessels (also called " ducts "), tracheids, and conducting parenchyma ; and the elements of the bark which transport the assimilable materials comprise the lep- tome and conducting parenchyma (Fig. 141). Water-conducting elements (TRACHEAL ELEMENTS) comprise the vessels (tracheae) and the tracheids, which resemble each other, except that the latter are single cells of prosenchymatic shape, while the former are very long tubes, varying from cylindrical to prismatic in shape, and consist of long rows of cells which are superimposed length- wise, the transverse walls being usually obliterated. B A * B zw FIG. 143. Forms of tracheae or vessels. A. — Longitudinal section of stem of Cucurbita Pepo showing various forms of tracheae: A, annular; S, spiral; D, double spiral; C, close annular; R, reticulate. B. — Tracheae in glycyrrhiza rhizome: W, wall; B, bordered pores; P, oblique simple pores. The tracheae or vessels are formed by the disintegration and removal of the transverse walls between certain superimposed cells, forming an elongated cell or tube, which occasionally retains some of the transverse walls (Figs. 142-144). The longitudinal walls are relatively thin and consist of lignocellulose, giving pro- nounced reactions with phloroglucin or aniline sulphate. Four types of vessels or tracheae are known : annular, spiral, reticulate, and porous. Those having the thickenings in the form of horizontal or oblique rings are known as ANNULAR TRACHEA; those having the thickenings in the form of spirals, which usually run from right to left, are known as SPIRAL TRACHEA ; those having the thickenings in the form of a reticulation are known as 18 274 A TEXT-BOOK OF BOTANY. RETICULATED TRACHEAE, and those with spherical or oblique slit pores are known as POROUS TRACHEAE or vessels (Figs. 142-144). In those vessels in which but few of the transverse walls are obliterated, the walls are marked by both simple and bordered • -@gu FIG. 144. Types of tracheae or vessels. A, vessels with annular and spiral thickenings in Phlox Carolina; B, longitudinal section through fibrovascular bundle in aconite, showing porous (p) and spiral tracheae (t), bast fibers (b), and some of the collenchyma cells (c) ; C, longitudinal section showing reticulate tracheae in scopolia; D, longitudinal section of the woody part of the rhizome of Spigelia, showing tracheae (t), tracheids (h), tracheae (r) with yellowish-brown, gum-like masses; E, portion of xylem of stem showing in Hyos- cyamus tracheae (t) with bordered pores and wood fibers (w), with simple oblique pores. .pores, which latter are described under tracheids. Vessels contain water, water-vapor, and air ; in some cases they contain sugar, tannin, mucilage, or resin. CELL-CONTENTS AND FORMS OF CELLS. 275 The tracheids are intermediate in character between tracheae and libriform, resembling the former in possessing bordered pores (Fig. 145) and scalariform thickenings; and the latter in being true cells, which are usually elongated and quite thick-walled, the walls giving distinct reactions for lignocellulose with phloro- glucin or aniline sulphate. One of the chief characteristics of tracheids is the BORDERED PORES (Fig. 145). These differ from simple pores in that the wall surrounding the pore forms a dome-shaped or blister-like FIG. 145. Bordered pores of the tracheids of the wood of Abies alba as viewed in longitudinal section: m, middle lamella; v, i, middle and inner layers of walls of contigu- ous cells ; C, pore-canal through which sap passes from one cell to another ; L, dome- shaped cavity of pore; S, separating wall or closing membrane which is usually thickened in the middle as shown at t. In older cells the separating membrane is broken as shown in the lower pore in figure 2. At the right in figure 4 is shown a surf ace view of a bordered pore, the dotted lines indicating the relation of the circles to the structure of the pore. — After Vogl. protrusion into the cell. On surface view the pores are either circular or elliptical in outline, the dome being circular or, if the pores are numerous and arranged close together, more or less polygonal (Figs. 143, 144). The number and distribution of bordered pores in the Coni- ferae are quite characteristic for some of the genera, and may be studied in any of the pines, the pores being most numerous in the radial walls (Fig. 69). 276 A TEXT-BOOK OF BOTANY. The leptome or sieve is distinguished from the other con- ducting elements in that the walls are thin and are composed of cellulose (Fig. 146). It consists of superimposed elongated cells, the transverse walls of which possess numerous pores which are supposed to be in the nature of openings, permitting of the 11 A 18- >o FIG. 146. Different forms of sieve pores: I, portion of sieve tube of Bryonia alba, II of Cucurbita Pepo, A longitudinal section and B in transverse section; III, portion of a sieve cell of Larix europcza showing round sieve pores; IV, an old sieve plate in Bryonia alba treated with chlor-zinc-iodide, showing the striated callous plates (c), (z) cell-wall, (s) sieve plate, (i) contents of sieve tube, (h) cell membrane, (c) callous plates. — After Dippel in "Das Mikroskop." direct passage of the contents from one cell to the other. This transverse wall, which may be either horizontal or oblique, is known as the SIEVE PLATE, and the thin places as pores of the sieve. The sieve plates are sometimes also formed on the longi- CELL-CONTENTS AND FORMS OF CELLS. 277 tudinal walls. When the activities of plants are suspended during the winter, there is formed on either side of the sieve plates a layer of a colorless, mucilaginous substance, known as callus, which has somewhat the appearance of collenchyma, but is colored brownish by chlor-zinc iodide. The sieve cells contain an albuminous substance somewhat resembling protoplasm ; in some instances starch grains have also been found. When the activities of the sieve tubes have ceased, they be- come altered in shape, and are then known as altered sieve. In the drying of plants a similar alteration is produced, and the sieve of vegetable drugs is referred to as ' obliterated ' sieve. Protecting cells include those cells which are located on the outer parts of the plant. The function of these cells is to lessen the rate of transpiration, or the giving off of water; to furnish protection against changes of temperature, and to protect the inner tissues against the attack of fungi and insects ; they also have a mechanical function (Figs. 147, 157). Depending principally upon their composition, these cells may be divided into two classes, namely, epidermal cells and cork cells. The epidermal cells constitute the outermost layer of the plant. They contain cytoplasm, but the plastids in some instances are wanting; in petals, etc., they also contain dissolved color- ing principles ; and on account of the relatively large amount of water which they contain they are classed among the important water-reservoirs of the plant. The outer walls are principally characterized by one or more lamellae of cutin, these uniting to form a continuous wall. The cutin is often associated with wax, this constituting the bloom of fruits ; less frequently such inorganic substances as calcium car- bonate, calcium oxalate, and silica are present, and not infre- quently mucilage is present, as in the walls of certain seeds (Fig. 119, A). On surface view the form of these cells varies from nearly isodiametric to oblong; they may also be polygonal or branched. In transverse section their radial diameter is much the shorter. In some instances the inner and side walls are considerably thick- ened, as in the seeds of a number of the Solanacese (Fig. 136, A). 278 A TEXT-BOOK OF BOTAXY. The epidermis usually consists of a single layer of cells, but may have additional layers underneath forming the HYPODERMIS, as in the upper surface of the leaves of species of Ficus (Fig. 113) ; D FIG. 147. Stomata and water-pores. A. — Transverse section through lower surface of leaf of stramonium: stoma, with guard cells (G), containing cytoplasm, nucleus and chloroplastids; N, surrounding cells; A, intercellular cavity usually filled with cell-sap or watery vapor; E, epidermal cells; M, mesophyll. B. — Surface section of upper surface of leaf of Viola tricolor showing four stomata. C. — Surface section of under surface of leaf of Viola tricolor showing five stomata. D. — A section through the margin of the leaf of Viola tricolor showing a tooth with three water-pores. E. — A water-pore of Viola tricolor in surface section. in some instances the hypodermis undergoes a mucilage modifica- tion, as in the leaves of buchu. Stomata. — Distributed among the epidermal cells are pairs of crescent-shaped cells known as a STOMA, and having an open- CELL-CONTEXTS AND FORMS OF CELLS. 279 ing or pore between them, which leads to a cavity beneath it. The two cells of the stoma are known as GUARD CELLS (Fig. 147, G). The adjoining walls of the guard cells are alike in transverse sec- tion, but the cells vary in shape in different plants. The guard cells are more or less elastic, and when the cells are turgescent, as when there is an abundance of water and root pressure is strongest, the contiguous walls of the cells recede from each other, forming an opening between them, thus permitting the exit of the excess of water taken up by the plant and the exhalation of the oxygen given off during assimilation, as well as the intake of the carbon dioxide used in photosynthesis. On the other hand, when the amount of water in the plant is reduced below the normal and the plant shows signs of wilting the guard cells flatten and the open- ing or pore is closed (Fig. 214). The cells beneath the stoma are loosely arranged, so that the air containing carbon dioxide may be readily diffused to the cells containing the chloroplastids. The guard cells may be slightly raised above or sunk below the surrounding epidermal cells, the number of the latter being characteristic for certain plants. (Compare Figs. 147, 211-218.) Stomata occur in the largest numbers on the blades of foliage leaves, being more numerous on the under surface, except in aquatic plants, where they occur only upon the upper surface. Water Pores. — Near the margin of the leaf and directly over the ends of conducting cells, not infrequently occur stomata, in which the function of opening and closing is wanting, and which contain in the cavity below the opening water and not air, thus differing from true stomata (Fig. 147, D, E). These are known as WATER PORES, and they give off water in the liquid form, the drops being visible on the edges of the leaves of nasturtiums, fuchsias, roses, etc., at certain times. Plant Hairs.- -The epidermal cells are sometimes specially modified centrifugally, giving rise to papilke, to which the velvety appearance of the petals of flowers is due ; in other cases this modification is in the form of hairs or trichomes (Figs. 148-155). These may be unicellular or multicellular, and in addition the latter may be glandular or non-glandular. Glandular hairs possess a head-like apex, consisting of one or more cells, and they secrete oil, mucilage, and other substances (Figs. 124, 125, 149, 15°)- 28'0 A TEXT-BOOK OF BOTANY. In the examination of technical products, as also in taxonomic work, the study of plant hairs is very important. They show a great diversity in form in not only genera and families but even in related species. They vary considerably in their distribution FIG. 148. Mostly non-glandular hairs and a few of the small glandular hairs covering the surface of the fruits of several species of Rhus: g, hairs on Rhus glabra, being more or less broadly top-shaped or carrot-shape to spatulate and occasionally narrow elliptical and from o.ioo to 0.400 mm. in length; b, hairs on Rhus typhina, being long and needle-like, varying from 0.750 to 1.500 mm. in length; c, hairs of Rhus glabra borealis, being intermedi- ate between those of Rhus glabra and Rhus typhina, varying from elongate spatulate and narrow cylindrical to needle-shaped, and from o.ioo to i.ooo mm. in length. not only in related species, but sometimes in varieties of the same species they show marked variation in size and form. In some natural hybrids intermediate forms of hairs of the parent species CELL-CONTENTS AND FORMS OF CELLS. 281 are found. This was pointed out by Kraemer in some studies on Rhus glabra and Rhus typhina (Amer. Jour. Phann., 1913, p. 404), in which a herbarium specimen in the New York Botanical Garden and labelled by Britton as Rhus glabra bor calls shows hairs which in form and size are intermediate between those of R. glabra and R. typhina (Fig. 148). Plant hairs may be divided into two principal groups: I. GLANDULAR HAIRS, or those in which the summit consists of one or more cells which secrete beneath the cuticle either mucilage, oils, or oleo-resins, and the summit of the hair possesses a more or less globular form. II. NON-GLANDULAR HAIRS, or those in which the summit of the hair consists of one or more rounded or pointed cells in which no secretion is formed beneath the cuticle. GLANDULAR HAIRS may be divided into five different groups : 1. Unicellular glandular hairs consist of a single tubular cell, the upper portion being more or less swollen and rounded (Fig. 149, A, B). Hairs of this type occur in the Euphorbiaceae, in which they more or less resemble Papillae. In the Compositse they contain a latex and appear to be connected with the laticifer- ous vessels. They also occur in the Anacardiaceae, Cornaceae, Geraniaceae, Leguminosae, Malvaceae, Menispermaceae, Onagraceae, Piperaceae, Ranunculaceae, Tiliaceae and Zygophyllaceae. 2. Multicellular glandular hairs consist of a number of forms ; either they are differentiated into a stalk and a head, or the stalk may be wanting when the hair has a spatulate or clavate form. These are often very characteristic for certain families, as the glandular hairs in the Labiatae (Fig. 124), which possess a short stalk, and a head portion with eight cells, the cuticle being raised like a bladder owing to the great accumulation of secretion. There are a great many types of multicellular glandular hairs (Fig. 149). They may be uniseriate, i.e., consisting of a series of cells with either a unicellular head (Fig. 149, Cf E, K, M), as in the Meni- spermaceae, Araliaceae, Malvaceae, Caryophyllaceae, Geraniaceae, etc., or they may be bicellular (Fig. 149, D, F, H, J , L, 0), as in the Cruciferae. The heads may consist of two to four cells (Fig. 149, G, V , F), as in the Burseraceae, or eight cells, as in the Labiatae (Fig. 149, [f7). Multicellular glandular hairs have been found in the following families : Aceraceae, Anacardiaceae, Araliaceae, Be- 282 A TEXT-BOOK OF BOTANY. B . 9 FIG. 149. Various types of glandular hairs. Unicellular hairs on Julocroton /M.S- cescens (A), Croton monanthogynus (B). Uniseriate uni-glandular hairs on Zollikoferia nudicaulis (C), Silene villosa (E), Geranium favosum (K), Boerhaavia repens (M). Glandular hairs with two-celled heads on Hesperis glutinosa (D), Pilyrodia salvifolia (F), Cyclamen persicum (H), Lysimachia Nummularia (J), Chenopodium Boirys (L), Diospyros Kaki (O). Glandular hairs with four-celled heads on Humid us Lupidus (G), Boswellia papyrifera (V), Humulus Lupidus (Y). Glandular hairs with five-celled heads on Combretum acideatum (Z), Humulus Lupidus (Y). Glandular hairs with six-celled heads on Rhododendron Dalhousia (X), hair characteristic on the Phaseolea (U). Glandular hairs with eight-celled heads on Lavandida vera (W). Glandular hairs with multicellular heads on Pieris Jloribunda (N), Begonia car olinia folia (S), Begonia preloniensis (s). Glandular hairs with four and eight cells respectively on Picramnia coccinea (P). Glandular hairs with two and four cells re- spectively on Cistus ladaniferus (R). Double glandular hair on Rhododendron lanatum (T) —Adapted from Solereder and redrawn by Hogstad. CELL-CONTENTS AND FORMS OF CELLS. 283 goniaceae, Berberidaceae, Bixaceae, Borraginaceae, Burseraceae. Capparidaceae, Caprifoliaceae, Caryopyhllaceae, Chenopodiaceae, Combretaceae, Compositae, Convolvulaceae, Cornaceae, Crassulaceae, Cruciferae, Cucurbitaceae, Dipsaceae, Ericaceae, Euphorbiaceae, Fagaceae, Geraniaceae, Hippocastanaceae, Hydrophyllaceae, Labi- atae, Leguminosae, Malvaceae, Melastomataceae, Meliaceae, Meni- spermaceae, Moraceae, Myrsinaceae, Nolanaceae, Nyctaginaceae, Nymphaeaceae, Piperaceae, Platanaceae. Plantaginaceae, Polemoni- aceae, Polygonaceae, Portulacaceae, Primulaceae, Rosaceae, Ru- taceae, Sapindaceae, Saxifragaceae, Scrophulariaceae, Simarubaceae, Solanaceae, Sterculiaceae, Theaceae, Tiliaceae, Umbelli ferae, Ul- maceae, and Valerianaceae. 3. Glandular leaf-teeth, as the name would signify, include the glandular hairs formed on the lobes of leaves. They vary in structure and may secrete mucilage, as in the Violaceae (Fig. 120) and in some of the Compositae, or they may secrete, in addi- tion, resin, as in the Rosaceae, or calcium oxalate, as in the Saxifragaceae. 4. Special forms of multicellular glands are found in the Aceraceae, in which a pair of glands are fused together. In some of the Compositae and Moraceae a group of glandular hairs are united. Other special types also occur in the Droseraceae, Ana- cardiaceae, Leguminosae, etc. 5. Hair-like external glands having a complicated structure have been observed in a number of families. They are limited to certain portions of the plant, being found in the Apocynaceae at the base of the leaves and in the Rubiaceae only on the stipules. They are usually very large, secreting considerable mucilage and resin. The glandular, shaggy hairs occurring on the stipules in the Rubiaceae are of this type, the secretion being often so abundant that the young leaves emerging from the stipular sheath are coated with this resin, which is even retained by the mature leaves. II. NON-GLANDULAR HAIRS are of three general types: I. Simple hairs (Figs. 148, 151), which may be unicellular or uni- seriate, — i.e., consisting of a series of superimposed cells. 2. Peltate or stellate groups (Fig. 153, D, E, H, K}, consisting of two or more hairs united at the base and spreading like a star. 284 A TEXT-BOOK OF BOTANY. o FIG. 150. Forms of glandular hairs: A, corkscrew-like hairs from the inner surface of the spurred corolla of lavender; B, longitudinal section of rhizome of Dryopteris mar- ginalis showing large intercellular space and an internal oil-secretion hair; C, hairs from stramonium leaf ; D, hairs from Digitalis; E, hair from sage; F, hair from eriodictyon; G. hairs from inner walls of pericarp of vanilla; H-, hair from cannabis indica; I, hairs from surface of fruit of Riius glabra; K, hairs from belladonna leaf. CELL-CONTENTS AND FORMS OF CELLS. 285 These may consist of one or more series of cells, separated by a columnar cell. 3. Shaggy hairs (Fig. 153, G), in which the epidermal layer of the column of cells is modified to papillae FIG. 151. Forms ot non-glandular hairs: A, hair from the epidermis of strophanthus; B, a hair from the capsule of Mallotus philippinensis (found in the drug known as kamala); C, hairs from the leaves and bracts of cannabis indica, two of them containing cystoliths of calcium carbonate; D, a hair from the under surface of the leaf of senna; E, hairs from leaf of digitalis; F, two forms of hairs from sage leaf; G, two forms of hairs from the leaves of wormwood (Artemisia Absinthium): a T-shaped non-glandular hair and a short glandular hair. which are directed upwards, giving the surface of the plant the appearance of being covered with rough hairs or wool. Non-glandular hairs occur on a large number of plants. They 286 A TEXT-BOOK OF BOTANY. vary in form and are very characteristic in a great many plants. The terms used to describe the various types of hairs are in a few instances rather simple, but there are so many modifications that nothing short of an illustration will suffice to define them. The simple hairs may be divided into a number of sub-divisions : (a) Papillose hairs, being short outgrowths of the epidermal cells, somewhat resembling the papillae found on the ventral surfaces of petals. This form is found in a relatively few families, (b) Unicellular hairs, being outgrowths considerably longer than papillae and occur in a large number of plants. This is also true of a third type (c), known as uniseriate hairs and in which there B FIG. 152. Forms of non-glandular hairs: A, twisted hairs from under surface of leaf of eriodictyon; B, lignified hairs from the epidermis of nux vomica; C, branching hairs from the leaf of mullein (Verbuscum thapsus). • are two or more ceils connected as in a chain. Among special terms frequently used the following may be mentioned: (d) Hooked hairs (Fig. 154, A, B), in which the summit is bent in the form of a hook, (e) Two-armed hairs (Fig. 153, D), in which the summit consists of two cells which diverge from each other and spread out horizontally or parallel to the surface of the leaf. (/) Stellate hairs (Fig. 151, B) consist of a group of cells ar- ranged around a simple point, as in the Cruciferae and Saxifra- gaceae. (g} Peltate hairs (Fig. 153, E) consist of a group of radially arranged cells, of which all or only some reach the centre of the shield, as in the Solanaceae, Malvaceae, Loganiaceae, and CELL-CONTENTS AND FORMS OF CELLS. 287 Rosaceae. (h) Candelabra or abietiform hairs (Fig. 153, L) are those which have a uniseriate main axis, interrupted at intervals by whorls of ray cells. These show considerable variation and are very characteristic in the Solanaceae, Acanthaceae, Leguminosae, Labiatae, and Euphorbiaceae. (/) Stinging hairs (Fig. 153, /), or those containing an irritating substance, as in the stinging nettle and other plants of the Urticaceae. The hairs are rather long, the FIG. 153. Several types of non-glandular hairs. Crystal hairs on Malanea macro- Phylla: A, showing hair with a single row of crystals; B, cell with 2 rows of crystals; C, transverse section of B, showing crystals. Two-armed hairs on Artemisia Absinthium (D) and Dichondra repens (H); F, uniseriate non-glandular hair on Pongamia glabra; E, longi- tudinal view showing two of the cells of a peltate hair on Solanum argenteum; G, shaggy hair on Calandrinia umbellata; J, upper portion of stinging hairs of Urtica dioica; K, cup- shaped peltate hair on Rhododendron A nthopogon; L, candelabra hair on Verbascum Thap- sus. — Adapted from Solereder and redrawn by Hogstad. summit bearing a spherical or ovoid head, which is obliquely in- serted and rather easily detached, thus leading to the emission of the contents. The stinging sensation was formerly stated to be due to formic acid, but it is now supposed to be in the nature of a substance related to the ferments. (/) Crystal-containing hairs. Calcium oxalate (Fig. 153, A, B, C), either in the form of rosette aggregates or prisms or needles, is sometimes present in the 288 A TEXT-BOOK OF BOTANY, rl FIG. 154. Hairs in the Composite: A, slightly curved or hooked hairs on the corolla of Dandelion; B, hooked hairs on the filaments of Inula; C, hairs on pappus of Tragopogon pratensis; D, hair from akene of Tragopogon pratensis; E, portion of barbed hair upon pappus of Inula; F and G, double hairs fromacheneof Tagetes tenuifolia; H, double hairs from achene of Inula; J, double hair from corolla of Calendula. CELL-CONTENTS AND FORMS OF CELLS. 289 FIG. 155, Characteristic branching hairs found on the stem, leaves, and calyx of Hyoscyamus muticus. stinging hairs of some of the Euphorbiaceae, as well as in some of the genera of the Cornaceae, Geraniaceae, Rosaceae, and Saxi- fragaceae. 19 290 A TEXT-BOOK OF BOTANY. LIGXIFIED HAIRS. — In some seeds, as in mix vomica, the hairs are strongly lignified, as are also the bases of the hairs of Stro- phantus hispidns. This is due to a lignocellulose modification of the wall, and, since broken hairs look more or less like fibers, one might easily be led astray in the study of powdered drugs. It is not usual to make a microchemical study of the walls of non- glandular hairs, but this subject is well worthy the attention of investigators. FALSE PLANT HAIRS. — While it is impossible for the careful student of plant morphology to mistake anything else for plant hairs, it is, nevertheless, worth while to call attention to some of the mistakes that are liable to be made. In works on systematic botany sometimes occur contradictory statements concerning the abundance or scarcity of hairs, especially as they relate to the flower. In a superficial examination, for instance, in the violets, large masses of germinating pollen grains with their tubes matted together are not at all uncommon in the throat of the corolla, and these have been mistaken for hairs. Furthermore, the mycelia of fungi may be mistaken for hairs, especially in young seedlings, as of hyoscyamus, belladonna, etc., where thread-like delicate branching hairs may occur. In the examination of economic prod- ucts, especially powdered drugs and spices, mistakes of this kind may occur, unless the student has devoted some attention to this study. In all studies of plant hairs the student should carefully locate the summits and bases, and unless these can be recognized, or if broken made to correspond to each other, one cannot say that hairs are present. CORK CELLS replace the epidermal cells of roots and stems that persist year after year. They are formed, as has already been stated, from a distinct meristem, called the phellogen. Cork cells differ from the epidermal cells in that the walls are uniformly thickened and on surface view are polygonal in shape. The walls consist of suberin, a substance allied to cutin ; in some instances they also contan lignocellulose, forming cork stone-cells, as in asclepias and calumba. The young cells may contain a thin layer of cytoplasm and a nucleus ; they usually also contain brownish masses of tannin or tannin-like compounds, and occasionally crys- tals of cerin or calcium oxalate. CELL-CONTENTS AA.J FORMS OF ELLS. 291 Cork not only occurs as a secondary protective layer, but may also arise in other parts of the plant as a result of injury, as in leaves, fruits, stems, and tubers. It also arises as a result of the disarticulation of the leaf in autumn. PERiDERM.--The epidermis is not adapted for the protection of the perennial plant organs on account of its thin, frequently delicate structure and its inability to continue with the increase in thickness of stems and roots. Hence it becomes replaced by the periderm, which consists of a lasting tissue, the CORK, and of a meristematic tissue, the PHELLOGEN, which reproduces the cork when it becomes torn or destroyed, by the continued growth in FIG. 156. Section through a secondary lenticel in the bark of Sassafras; e, epidermis: st, stone cells; phel, phelloderm derived from secondary phellogen and having thick ligni fied wall; p, parenchyma; c, cork; com, complementary cells.^After Weiss. thickness of stems or roots. Cork is not only of sub-epidermal origin, but may occur deeper in the cortex (Fig. 158), or even in- side the endodermis. In the latter case, as in roots, it owes its existence to the activity of the pericambium. Superficial, i.e., hypodermal cork, is extremely rare in roots. Not infrequently a layer of cells is formed inside of the phellogen, being termed the phelloderm. They usually contain plastids ; the walls are moder- ately thick and free from intercellular spaces (Fig. 156). Lenticels may be described as biconvex fissures in the periderrrr which permit of the easy access of air to the intercellular spaces of the rather loosely arranged cells lying beneath them (Fig. 292 A TEXT-BOOK OF BOTANY. 156). They usually arise as the product of a meristem situated beneath the stomata of the epidermis, the stomata being replaced by them when cork is developed. Several types of lenticels are FIG. 157. Bark of Rhamnus Purshiana showing large whitish patches of lichens, and numerous lens-shaped lenticels, distinguished. They are quite characteristic and prominent in a number of barks, as those of species of Betula, Prunus, Rham- nus (Fig. 157), etc. CELL-CONTENTS AND FORMS OF CELLS. 293 FIG. 158. Development of Cork: A, in epidermal cells of stem of Oleander; B, development of cork in upper row of collenchymatous cells in the stem of Sambucus nigra; C, development of cork meristem in cells of cortex immediately above the primary bast fibers in Rubus fruticosus; D, development of primary cork in cells above the secondary bast fibers of Clematis Vitalba; e, epidermal cells; k, cork; km, cork-meristem; c, collen- chyma; b, parenchyma; b, b, primary bast fibers; b', secondary bast fibers; K, young cork cells. — After Dippel in "Das Mikroskop." BORK. — The cork cambium or phellogen develops before ma- turity in the green stems of woody plants belonging to the dico- tyledons. It may develop in the primary or secondary tissues 294 A TEXT-BOOK OF BOTANY. (Fig. 158). When the phellogen develops in the deep-seated tissues, the cells outside of the corky layer sooner or later die and slough off. This is due to the fact that the cork cells are suberized and do not permit the passage of the cell-sap containing foo-d sub- stances. In large shrubs and trees with thick stems and trunks A B Ef FIG. 159. Development of Bork: A, in bark of cherry (Prunus Cerasus), showing a layer of periderm (k) with thin-walled cork cells; bast fibers (Bf); parenchyma (p); stone cells (st) occasionally branching and lengthened into fibers. B, inner layer of periderm of Quercus Robur, showing compactly arranged, thick-walled cork cells (P) filled with a reddish phlobaphene or altered tannin; starch-bearing parenchyma (p) ; stone cells (st); sieve tubes (Bg); bast fibers (Bf) ; prism of calcium oxalate (kr) ; several rows of thick- walled, porous cells (x). — After Dippel in "Das Mikroskop." a number of successive layers of cork or periderm are formed. These layers with the dead cortical tissues between them persist to some extent and constitute what is known as bork, i.e., bork consists of a number of alternate layers of periderm and cortical CELL-CONTENTS AND FORMS OF CELLS. 295 tissues. The cork cells in different trees are variously developed and accordingly two types of bork formation may be distinguished. In sycamore, cherry and plum trees the cork cells are only slightly thickened (Fig. 159) and the periderm in the form of layers FIG. 160. White oak bark with the fissured corky layers (bork). separates from the tree annually. In the oaks, chestnuts and tulip poplar the cork cells (Fig. 159) are thick walled and com- pactly arranged so that, under the stress of growth and thickness of the bark, the layers of periderm are split longitudinally, giving 296 A TEXT-BOOK OF BOTANY. rise to the deep furrows (Fig. 160) which are so characteristic of the outer surface of our large trees. Laticiferous or milk tissue occurs in all those plants which emit a milk- juice on being cut or otherwise wounded. The juice may be colorless, as in the oleander ; whitish, as in the Asclepia- daceae, Apocynaceae, etc. ; or yellowish, as in the Papaveraceae. It contains caoutchouc, oils, resins, mucilage, starch, calcium oxalate and alkaloids as well. The walls are relatively thin and consist chiefly of cellulose. The tissue consists either of single cells of definite length, as in the Papaveraceae, or the cells may be of indefinite length, as in the Asclepiadaceae, or it may consist of a more or less branching network (Fig. 127) formed by the anastomosing of a number of cells, as in Taraxacum (consult paragraph on Latex, pp. 238-241). As has already been stated, the latex of plants contains a num- ber of plastic or trophic substances, — i.e., those which, either at once or after being stored for a time as reserve food, are drawn into metabolism and serve as nutrient material. They also con- tain a number of aplastic or non-trophic substances, as caoutchouc, resin, alkaloids, volatile oils and tannin, which are in the nature of metabolic by-products and are incapable of further metabolism. \Yhile it is highly probable that the laticiferous tissue, on account of its being always associated with the phloem, functions to some extent for the transportation of plastic substances, yet it serves another purpose, viz., to protect the underlying cells after injury of the plant by insects or herbivorous animals. This protection results from the rapid coagulation of the exuding latex upon exposure to the air and forming a varnish-like surface. In some cases the latex contains a poisonous principle which exercises a protective function. In Rhits Toxicodcndron the principle causing the eczema, namely toxicodendrol, is supposed to be formed in laticiferous tissues being transferred to the hairs, which upon being broken liberate the poison CELL-CONTENTS AND FORMS OF CELLS. 297 o p n O ""1 re"3 H- • O a § en f n n C •-i •-! 3 f> re p 3 0) CLASS. K'o •0 13 H-J M 5'3 Z V 13 *"" *? t3 Q O 0 P 0 ^ C-« ^ p r+ **• r P fO •o 5*2 A|| . O < 0 S-'g 0 fg-g, s cr re o o •o 3*5; ° 2 -' c" -3wi 3 TO g-|s re" re 3 3 en 3 p t— ' O en i-J J-i. <-«• o o P r-t- 3 3"— ; 1*^ *** en P r+ 3 re 2» r* ***» C^ rex re s-9 Cu en 3* 3 P til ?[l Sg. If 0 0 Ifi 1 £^£Lg£ r P ° S ° n.SocS^ 3'o.p 3 § *< P a? £i£. ? ?-<*.N1 Nearly isodia metric or cyl indraceous, or branchin O •-»> 0 P C ^ C* "1 &3 ^ «j« h^ ^5 ^ - f^ r . , CO o 3 re re en* ICHANICAL CE TO ii r o ,.,,1/1 t/5 ffi re o O 0*3 o* o en rt- « o n D. re << en O l-— 3^5" PM 0. 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C? 3-rt 3 0*0 2. re ~>3 3 "iTO re P CO re' re re i -.o r+ 7) 3*- re filHillii en re 7 o £*"> it x i "I Protoplasm, plastids, cell sap Isodiametric polygonal 01 branching The outer layer of herbaceous plants Epidermis PROTEC rt "i ' C, i" en -• H 0 •O O •I re 9 P c^ III •1 t— t re 3 en 3 5' 3' 3 3 en p P w O e*+ en rf e -I re p cr re Isodiamet or polygo ss-^^ 2 O-cn ^ P'JE c o en -i "1 c*1 *1 JT*1 n o P-T ^JG CELLS. en "-^ i — ••• 3 nTo 3 2. 3 r* re S "5* 2. 2. M w s, S 3 w* O O O w r r1 C73 CHAPTER III THE OUTER AND INNER MORPHOLOGY OF HIGHER PLANTS. INTRODUCTORY. IT may be well to repeat at this point that on germination of the megaspore the female gametophyte bearing the egg-cell is formed, and that on germination of a microspore the male gameto- phyte bearing male nuclei is organized. The union of egg-cell and a male nucleus gives rise to the sporophyte embryo contained in the seed, which develops into the plant we see, namely, the sporophyte. The female gametophyte always remains concealed within the embryo-sac, and the male gametophyte may be said to embody the protoplasmic contents of the pollen tube. A complete flower is made up of floral leaves and sporophylls, the latter being essential for, the reason that they give rise to the spores. While the flower belongs to the sporophyte generation, the propagative organs may be said to be derived from both the sporophyte and gametophyte, and hence may be distinguished as asexual and sexual. The following outline illustrates their derivation : Egg-apparatus, containing egg-cell or Propagative Organs Sexual, derived from gametophytes (sex- ual generation) Asexual, derived from sporophyte (asex- ual generation) 298 female gamete Male Generative-cell, giving rise to male nuclei or male gametes Microsporangium (pollen sacs) giving rise to microspores (pollen grains) Megasporangium (nucel- lus) giving rise to mega- spore (embryo-sac) MORPHOLOGY OF HIGHER PLANTS. 299 The vegetative organs comprise the root and shoot, the latter being usually differentiated into shoot axis or stem, and leaves. The usual type of shoot is one which bears leaves and is exposed to the light. The work of carbon dioxide assimilation (photosyn- thesis) being carried on for the most part by the leaves, the axis is sometimes spoken of as the " assimilation shoot." FIG. 161. A, advanced stage of germination of the common garden pea (Pisum sa- tivum) showing growing point of root protected by root-cap (p); root branches or second- ary roots (rb); hypocotyl (he); epicotyl or stem above the cotyledons (ec) ; cotyledons (one in view) (c). B, plantlet of white or yellow mustard (Sinapis alba) showing copious development of root-hairs (h). I. OUTER MORPHOLOGY OF THE ROOT. THE ROOT, or descending axis of the plant, normally pene- trates the soil, absorbing inorganic substances in solution and act- ing as an anchor and support for the shoot. True roots are found only among plants having a vascular system, as the Spermophytes and the higher Pteridophytes, although, on the other hand, some of the higher plants do not possess them, as certain of the sapro- phytic orchids and some of the aquatic plants as Utricularia, 300 A TEXT-BOOK OF BOTANY. Lemna, etc. If we take a germinating plant and mark the root into ten equal divisions, beginning at the apex, and place the plant in a moist chamber, it will be found in the course of one or two days that the marks between I and 5 have become much FIG. 162. Longitudinal section through the tip of the root of Indian corn (Zea Mays) showing root-cap: a, outer layer; i, inner layer. — After Sachs. farther apart, and that the growth in this region is about three times that between 5 and 10. This experiment indicates that the growth of the root takes place at or near the apex, this region being known as the point of growth, or point of vegetation (Fig. 162). MORPHOLOGY OF HIGHER PLANTS. 301 Upon examining the tip of a very young root by means of the microscope, it will be seen that the growing point is protected by a cup-shaped body of a more or less solid structure and frequently mucilaginous ; this is known as a ROOT-CAP. Its function is to protect the growing point, and it exists in all roots of terrestrial, epiphytic, and aquatic plants except the parasites. Just above the root-cap there is developed a narrow zone of delicate hairs, which arise from the surface cells and are usually thin-walled and unicellular. These are known as ROOT-HAIRS (Fig. 161, B) and their function is twofold: (i) They secrete an acid which renders the inorganic substances of the earth soluble, and (2) they absorb these and other substances for the nourish- ment of the plant. It should be stated that there are a number of plants which for various reasons do not possess root-hairs, such as water-plants, marsh-plants, certain Coniferse, Ericaceae, etc. When the primary root persists (as in Gymnosperms and Dicotyledons) it increases considerably in length and becomes ramified ; if, at the same time, it increases in thickness, and much more so than its branches, then it is called a TAP-ROOT (as in Dancus Beta, etc.). In the vascular cryptogams (Pteridophytes) and the monocoty- ledons the primary root is generally thin and weak, frequently but little ramified, and disappears at an early stage, being re- placed by SECONDARY ROOTS,, as in Zea. Secondary roots may arise not only upon the stem but even upon leaves, as in Begonia and Bryophyllum. The term LATERAL ROOTS is restricted to those that develop from the root alone. The development of roots upon shoots or of so-called ' AD- VENTITIOUS ROOTS'" occurs in nearly all of the woody plants of the Spermophyta. Many annual herbaceous plants do not possess this capacity at all. The adventitious roots arise from ' root- primordia ' which are formed under the cortex of the shoots. While ordinarily they do not develop upon the shoots, yet if cuttings are made, as of Coleus, Geranium, Rosa, etc., we find ' either singly or on both sides of the axillary buds " the develop- ment of adventitious roots from the latent root-primordia. Influence of Gravity.- -The root is popularly supposed to grow downward, in order to avoid the light. On the other hand. 302 A TEXT-BOOK OF BOTANY. the theory has been established (as a result of Knight's experi- ments) that the root grows downward by reason of the influence of gravity. In addition it may be said that the principal functions of the root, namely, those of absorbing inorganic food materials and of fixing the plant to the soil, determine in a measure the direction of its growth. The tendency of the root to grow down- ward is a characteristic which distinguishes it from other parts of the plant, and it is said to be POSITIVELY GEOTROPIC (Fig. 163, A). FIG. 163. A, seedling of Brassica nigra in which root and stem have curved into a vertical position after being laid horizontally. B, seedling of Sinapis alba, the hypocotyl showing a positive, the root in water a negative heliotropic curvature. The arrows show the direction of the incident rays of light. — After Pfeffer. The influence which gravity has on plants may be best under- stood by bearing in mind that gravity is a constant force which acts perpendicularly to the surface of the earth, and that all parts of the plant are subject to its influence. The organs of plants respond in different ways to the action of gravity, but a clear distinction should be made between mere mass attraction, or that manifestation of the force of gravity whereby the heavily laden branch of a fruit tree bends downward, and the stimulus which causes the primary root of a plant to grow downward and the shoot to grow upward. \Yhile all parts of the plant are subject to the influence of gravity, not all the organs of plants respond in an equal degree. This is well illustrated by roots themselves. MORPHOLOGY OF HIGHER PLANTS. 303 It is well known that, whatever the position of the seed at the time of germination, the young radicle begins to grow perpen- dicularly downward (Fig. 163, A ) . The branches, however, which arise on the primary root are less positively geotropic and, instead of growing downward parallel with the primary or tap root, di- verge at an angle from it (Fig. 161 ). The secondary branches are still less affected by gravity and diverge still more from the per- pendicular, or grow out horizontally, while still others do not FIG. 164. Over-turned tree trunk showing spreading root-system, the main or tap root having died away appear to be in the least affected by gravity and grow freely in any direction. In the case of large trees we frequently find that the lateral roots spread out in a more or less horizontal plane near the surface of the earth, and if the main root has died the influence of gravity is not very evident (Fig. 164). But here it must be re- membered that gravity was instrumental in determining the direc- tion of growth at an earlier stage. This spreading of the roots near the surface of the earth is of decided advantage to plants, for it enables them to avail themselves of the better soil of the surface 304 A TEXT-BOOK OF BOTANY. layers. As indicated, gravity also determines the upward perpen- dicular direction of the shoot, which is therefore said to be NEGATIVELY GEOTROPic, but, as in the case of the root, the branch'es are less influenced by it and hence diverge at various angles from the main axis. Some of the other effects of gravity may be noted. If the end of a shoot be cut off, the branches next to the top will grow per- FIG. 165. Mangrove forest (Rhizophora Mangle}, showing the habit of growth, es- pecially the numerous aerial roots which form an almost impenetrable thicket. The man- grove is common along the southern shores of Florida, in the Bahama Islands, and in the West Indies. Many shellfish, lobsters,- and other forms of sea life are often found clinging or attached far up on the roots where they become lodged during high tides. — Photograph from article by Henry Trimble on Mangrove Tannin in Contributions from the Botanical Laboratory of the University of Pennsylvania, 1892, p. 50. pendicularly upward and thus assume the work of the main axis. Likewise in the case of roots, if the apex of the main or tap root be cut off, the branches near the end will assume a perpendicular direction. It will frequently be noticed in the case of trees which have been uprooted or where branches have been bent over hori- zontally that the new branches which arise grow perpendicularly upward. Creeping shoots furnish another good example showing MORPHOLOGY OF HIGHER PLANTS. 305 FIG. 166. Tutferous root of Ginseng (Panax quinquefoliuni). The root on the left is a fresh specimen and was grown in the United States. The one to the right was purchased at a Chinese bazaar. It is translucent, of a yellowish-brown color, and has the characteristic shape and markings considered desirable by the Chinese. The markings on the upper segment of the specimen are stem scars which are usually found on old roots. The trans- lucent appearance is no doubt due to the manner of treatment. While the method is not generally known, similar specimens may be prepared by treating the recently gathered roots with freshly slaked lime. the influence of gravity, the branches growing upward and the roots downward. The root exerts a certain amount of upward pressure on the liquids in the stem. This fact can be demonstrated by cutting off 20 3o6 A TEXT-BOOK OF BOTANY. the stem just above the surface of the earth and attaching thereto a glass tube by means of a tightly-fitting rubber tube. It is de- sirable to perform this part of the operation under water and to have the glass tube partly filled with water at the beginning of the experiment. This is done to prevent the clogging up of the vessels with air, which prevents the ready passage of fluids through them. If the root is now kept moist, the osmotic pressure of its cells forces water up into the glass tube, sometimes to a height of several feet. Experiments on the begonia and on many other plants succeed very well, but for some reason the geranium is impracticable to work with. The manometer devised by Ganong, while not showing the quantity of water forced up by the root, shows the amount of pressure exerted, which is really the most important fact to be ascertained. Modified Roots. — Roots which arise from the nodes of the stem or other parts of the plant are known as secondary or adventi- tious roots. These include the aerial roots of the banyan tree and the Mangrove (Fig. 165), which are for the purpose of sup- port ; the roots of the ivy, which are both for support and climb- ing, and the roots of Indian corn and many palms which serve both for support and the absorption of nourishment. Under this head may also be included the aerial roots of orchids and the root-like structures, or haustoria, of parasites, as of mistletoe and dodder, which penetrate the tissues of their host plants and whose vascular strands come into most intimate relations with those of hosts. Of special interest also are the breathing roots of certain marsh-plants which serve to convey oxygen to the submerged parts ; and the assimilation roots of certain water-plants and epiphytes, which are unique in that they produce chlorophyll. In certain plants the roots give rise to adventitious shoots, as in Prunus, Rubus, Ailanthus, etc., and in this way these plants some- times form small groves. Root Tubercles.- -The roots of the plants belonging to the Leguminosae are characterized by the production of tubercles, nodules or swellings (Fig. 167) which have been shown to have a direct relation to the assimilation of nitrogen by the plants of this family. Like carbon, nitrogen is one of the elements essential to plant-life, being one of the constituents of protoplasm and MORPHOLOGY OF HIGHER PLANTS. 307 present in various nitrogenous (protein) compounds which occur as normal constituents of the plant. The nitrogen required by plants is derived either from nitrogen salts contained in the soil, as nitrates and ammonium salts, or from the free nitrogen of the atmosphere. While most of the higher plants are able to assimilate nitrogen compounds existing in the soil, only the Leguminosas and Aristolochiacese, with possibly a few exceptions, are able to assimilate atmospheric nitrogen, and in this respect the FIG. 167. Root tubercles on Lupinus, one of the Leguminosce: A, roots with tubercles; B, transverse section of root showing the cells (b) which contain the nitrogen bacteria.— A. after Taubert; B. after Frank. majority of the Leguminosse stand as a class by themselves. Apparently in direct relation to this character stands the fact that the seeds of these plants contain a high percentage of nitrogen. This special ability of the Leguminosse to fix atmospheric nitrogen in the plants depends upon the presence of the nodules, which are due to the infection of the roots by a soil-bacterium ( Pscudouionas radicicola), although the precise mode of fixing the nitrogen is 3o8 A TEXT-BOOK OF BOTANY. not known. The bacteria seem to be localized in the nodules and are not found in any other part of the plant. It has been shown that when the roots of leguminous plants are free from nodules they do not have the power of assimilating free nitrogen. On the other hand, when the nodules produced by the bacteria are developed, the plants will grow in soil practically free from nitrogen salts. Because of this power the plants of this family are useful in restoring worn-out land, i.e., land in which FIG. 168. Transverse section of a root bearing root hairs; the latter are thin walled, irregularly bent, and attached at various places to small particles of soil. The hairs secrete an acid, rendering the inorganic substances soluble, which are then diffused through the walls of the hairs, transmitted to the cortical parenchyma and distributed through the conducting cells of the xylem to the shoot. — After Frank. the supply of nitrogen is exhausted, and they thus play an impor- tant role in agricultural pursuits. The enriching of the soil is accomplished by ploughing under the leguminous crops, as of clover or alfalfa, or allowing the nodule-producing roots to decay, when the nitrogen compounds are distributed in the soil. (Consult Bulletins on " Soil Inoculation for Legumes," issued by the Bureau of Plant Industry, U. S. Department of Agri- culture.) MORPHOLOGY OF HIGHER PLANTS. 309 THE INNER STRUCTURE OF THE ROOT. Primary Structure. — If we make a transverse section of the young portion of a root (Vascular Cryptogam, Gymnosperm, or Phenogam), we notice the following tissues (Figs. 169-174). The outermost tissue is EPIDERMIS (E), it being generally thin- walled and destitute of cuticle; it is, as a rule, hairy, and these hairs, which are relatively long, but always unicellular, are known as ROOT-HAIRS (Figs. 161, 168) ; they ramify but very seldom. Inside the epidermis there is frequently present a HYPODERMIS OLY > i FIG. 169. Radial vascular bundle in root of Allium ascalonicum, showing a large central trachea from which radiate five small groups of tracheae and between which are the groups of leptome or sieve; p, layer of pericambium or pericycle; d, transition cells or pas- sage cells in the endodermal layer, and which permit the easy transfer of substances between the cortical parenchyma and the tracheae of the stele. — After Haberlandt. (sometimes referred to as an EXODERMIS) composed of a single layer of cells or, at the most, of but several layers, the cells of which differ in shape and size from those of the epidermis and the adjoining cortical parenchyma. The hypodermis takes the place of the epidermis when the latter is worn off, except in the few cases where hypodermal cork becomes developed, as in Cephalanthus, Solidago, and in the Bignoniaceae. The root bark is composed of parenchymatous cells, being 310 A TEXT-BOOK OF BOTANY. commonly referred to as the CORTEX, and is either homogeneous or divided into two zones, the outer or peripheral being composed of thick-walled cells which naturally belong to the hypodermis and an inner or internal strata made up of thin-walled cells. The cells of the cortical parenchyma may contain starch, calcium oxalate, calcium carbonate, and there may be associated with them FIG. 170. Cross-section of the primary root of a germinating plant of Phaseolus multijlorus, showing development of secondary structures: p, group of primary vessels; g, larger tracheae of secondary development formed between the four primary strands of xylem; b, the four groups of phloem alternating with the four initial groups of xylem and beneath which secondary tracheae are forming (gy) ; pc, pericambium (pericycle), a layer of cells beneath the endodermis (s). A few layers of cortical parenchyma are shown outside of the endodermis. In the middle is a well-developed pith (M) which sometimes is developed in roots. — After Sachs. secretory cells or receptacles. Immediately beneath the innermost layer of cortical parenchyma is a distinct layer of cells usually considered part of the cortex and known as the ENDODERMIS. It consists always of a single layer of cells, without any intercellular spaces, and the radial walls show in transverse section Casparyan spots,1 depending upon a local folding of the cell-wall, which is here suberized. In the course of time the cell-walls of the en- 1 " Physiologische Pflanzenanatomie," by Dr. G. Haberlandt, p. 245. MORPHOLOGY OF HIGHER PLANTS. 311 dodermis frequently become thickened, either all around, or only on the inner or radial walls, so that we might speak of an O- endodermis as in Honduras sarsaparilla or an LT-endodermis as in Mexican sarsaparilla, according to the manner of thickening. FIG. 171. Cimicifuga. Transverse section of the central part of a mature root in which the secondary changes are completed: a, parenchyma of primary cortex; b, endo- dermis; c, cambium zone; d, trachea? in secondary xylem; e, broad, wedge-shaped medullary ray; f , outer portion of one of the primary xylem bundles; g, pericycle-parenchyma beneath the endodermis; h, inter-fascicular cambium. — After Bastin. This is especially the case in the monocotyledons where the walls of the endodermal cells become completely suberized and im- permeable to water. In some roots the cells of the endodermis may be uniformly thick- walled throughout, while in others some 3i2 A TEXT-BOOK OF BOTANY. of the cells may remain thin-walled, and these cells, the so-called " transition cells ' or " passage cells," form channels of com- munication between the cortical parenchyma and the vessels of the stele (Fig. 169) ; they are therefore located just outside the peripheral vessels of each ray of the xylem (or hadrome). Inside the endodermis is the STELE, formerly called the central- cylinder. In this the peripheral stratum, sometimes composed of two or three layers of cells, represents the PERICAMBIUM for PERICYCLE). The cells are generally thin-walled, and in Dicotyle- dons and Gymnosperms are able by cell-division to form cork and FIG. 172. A transverse section through the root of a germinating pea-plant (Pisum) about 40 mm. from the tip, showing the origin of a root-branch (RB); E, epidermis; C, pri- mary cortex; X, hadrome (vessels); P, leptome (sieve); EN, endodermis. secondary cortex, but in all vascular plants it is capable of giving rise to 'lateral branches' or "lateral roots' (Figs. 161, 172), hence it is frequently referred to as the " RIIIZOGEXOTS LAYER." Inside the pericambium (by some authors compared with the pericycle of the stem) we find strands of phloem (or leptome) (P) alternating radially with a corresponding number of strands of xylem (or hadrome) (X). The number of these strands vary in the different groups of plants (Figs. 169-174), being highest in the monocotyledons where a pith is developed, as in sarsaparilla, several grasses, palms, etc. This peculiar arrangement of the MORPHOLOGY OF HIGHER PLANTS. 313 phloem and xylem, as separate strands alternating with each other and not being located, as in stems, in the same radii, has given rise to several adverse views. Some authors have considered the root-stele as one single mestome-strand for fib ro vascular strand), while others, especially of recent date, consider it to be composed of several MESTOME STRANDS. The xylem or hadrome contains tracheae or vessels, the periph- eral being spiral and narrower than the inner, which are scalari- form or reticulate. The tissue in the center of the stele in mono- cotyledons is not uncommonly made up of parenchyma cells, and FIG. 173. Primary structure in the root. Transverse section ot root of pea (Pisum) about 40 mm. from the root-cap: H, epidermal cells, some of which are developed into root-hairs; C, primary cortex; EN, endodermis; PC, pericambium; X, hadrome, composed of tracheae; P, leptome, composed of sieve cells, the hadrome (vessels) and leptome (sieve) forming a triarch radial fibrovascular bundle. corresponds exactly with the pith of the stem. In roots it is often called CONJUNCTIVE TISSUE, and the cells may contain starch and crystals of calcium oxalate. Secondary Structure. — In roots that are able to increase in thickness (as in Gymnosperms and Dicotyledons), the increase depends upon the activity in the pericambium, some of the cells becoming meristematic. These meristematic cells are known as phellogen, developing cork outwardly and secondary cortex in- wardly. The meristem of the stele or cambium also becomes very active and develops on the inner face of the phloem and extends 3i4 A TEXT-BOOK OF BOTANY. from there to the outside of the peripheral vessels of the xylem (Fig. 174) ; thus a continuous cambial zone gradually arises. From this zone secondary tracheae or vessels become developed on the inner face of the primary phloem, while secondary phloem becomes differentiated outside the primary rays of xylem ; or only parenchyma develops outside the primary xylem, resulting in CA-- 5P-- FIG. 174. Section in the older part, higher upon the root of pea (Pisum) , showing in addition to what has been observed in Fig. i 73, the beginning of the change from primary to secondary structure: CA, the development of a cambium; SX, secondary hadrome (or vessels), and SP, secondary leptome (or sieve). the formation of secondary PARENCHYMA-KAYS (or medullary rays). In other words, the original radial structure of the stele changes to the collateral type (Fig. 175). Owing to this increase within the stele, the peripheral tissues from the endodermis to the epidermis naturally become broken and are subsequently thrown off, but are replaced by the pericambial cork and secondary cor- tex derived from the pericambium. The older roots, then, of Gymnosperms and Dicotyledons thus resemble the structure of stems, except that no pith exists in these roots, at least not usually. MORPHOLOGY OF HIGHER PLANTS. 315 Some differences are, however, quite noticeable in some instances, as in the thick roots of Beta, Radish, etc., where the wood paren- E x — EN m M M FlG. 175. Fully developed secondary structure in root. Transverse section of root of pea (Pisum) at the end of the summer's growth: E, some epidermal cells with fragments of root-hairs; C, primary cortex; EN, endodermis; K, pericambial cork; B, bast fibers; SC, secondary cortex; S, sieve; T, tracheae; W, wood fibers; WP, wood parenchyma; M, medullary rays; the tracheae (or vessels) and leptome (or sieve) forming open collateral fibrovascular bundles, these being found in dicotyledons with but few exceptions. chyma is usually abundant, thin-walled, and not lignified, the annual rings also being mostly indistinct. The characteristic distinguishing the primary and secondary 3i6 A TEXT-BOOK OF BOTANY. - — A^Cil *- Lvrf^^^T^Si5r* '( "Vcs^"^*/' '-^7 J* ijaigHK@i%i ^ P ^ '&P?*Mj iSS/SaM myW£- .^i^g/5.7^; ; t»V •Id'l- Sy, -t .k s FIG. 176. Glycyrrhiza: A, transverse section; B, longitudinal section. B, bark; H, wood; X, cambium zone; ph. cork cells; rp. cortex; p, parenchyma; k, crystal fibers; s, sclerenchyma fibers, including wood fibers occurring in the wood and bast fibers present in the bark; t, tracheae; m, medullary rays. — After Meyer. MORPHOLOGY OF HIGHER PLANTS. 317 structures of dicotyledonous roots may be summarized as follows : PRIMARY STRUCTURE: Epidermis and root-hairs. Hypoder- mis. Primary cortex consisting of parenchyma. Endodermis, pericambium, xylem arranged in radial rays which alternate with phloem or sieve strands, constituting a radial nbrovascular bundle (Figs. 169-174). SECONDARY STRUCTURE: Cork cells, phellogen, secondary cor- tex consisting of parenchyma. Phloem, cambium, and xylem arranged in radial groups, forming open collateral nbrovascular bundles. Medullary rays separating the fibrovascular bundles (Figs. I75-1/;)- Sometimes, as in glycyrrhiza and valerian, a number of paren- chyma cells are found in the center of the root, these constituting the PITH (Fig. 176) or medulla; but they are usually wanting in dicotyledonous roots. Wood and bark are terms used to distinguish those portions of the root or stem separated by the cambium ; all that portion inside of the cambium, including xylem, medullary rays, and pith, being known as the WOOD. The BARK includes the hadrome, the medullary rays outside of the cambium, and the tissues formed by the phellogen, viz., secondary cortical tissue and cork. The following diagram of the secondary structure of a dicoty- ledonous root may be of assistance in understanding the origin and relation of the tissues comprising it : Wood made up of Cambium produces Bark made up of. Pith, which may be wanting. ['Composed of vessels, wood parenchy- i ma and wood fibers ; or tracheids may Xylem »*• n* s* w — g. BPg en -• c*- TO "I Cr" jq i— < CD &• O "I P og ft> < O 1 3 •d ^ 3 « c g. P TO^ O S- ^. cr™ C a c *S8 3' C 3 O ET, £» w s° STw M.«5*r5 Q* r+ ^ O Gl I TO 3* en ^ ^ "» OT 3 3 3* a ^s :.!;;*. " >-* w. _ " rv . * TO O p g3^ |a 3 s. _. o P &JE o ^ • •< n m ft- 5'° EJ* 3 3 » Q O ?B CD -^ < CD CD ft> o n & — § g ^ >3 o> p J± crjS* £ I? n- 3 i— > c~^ 334 A TEXT-BOOK OF BOTANY. proximity their limbs will lash each other, causing a flattening of the top which is very characteristic in the groves of trees on the sea coast. In this way it is possible for the whip-like branches of the birch to mutilate even the tops of the fir tree, changing their spire-like summits to deliquescent crowns. Injuries causing an alteration in the form of plants are also caused by ruminating animals and leaf -devouring insects. GALLS.- -These are abnormal developments on the young twigs, leaves, and flowers, being caused by the punctures and presence of the deposited ova of quite a variety of insects. Galls vary in size, form, and general appearance. They are only capable of being produced either in meristematic cells or in tissues that are capable of exercising this function. They are never formed on mature stems, leaves, or flowers. The older parts may be eaten and destroyed by insects, but they are not capable of being meta- morphosed. In these growing tissues the mother insect lays her eggs, which upon further growth, either through the secretion of particular substances or otherwise, determine the direction of growth of the cells and the final product which shall be formed. As has already been stated, galls show considerable variation, and, as there are many hundreds of distinct galls, various attempts have been made to classify them. Kuster has proposed an ana- tomical classification as follows: I. Galls in which there may be an enlargement of cells, but no cell multiplication ; 2. Soft galls, composed of numerous cells, the resulting product being more or less fleshy ; 3. Hard galls, in which there is an active cell division, and sclerotic modification of the external layer so as to prevent the drying up of the gall in summer and to guard against attack by birds and other animals. Modry ( Beitnige zur Gallenbiologie) , on the basis of Krister's classification, has given a very compre- hensive review of the various structural (both external and in- ternal) characters of the various groups of zoo-cecidia. In a classification of galls Thomas has suggested as a class name for these structures the word CICCIDIEX (meaning nut-gall). The cecidien or galls are divided into two main groups, as fol- lows : I. PIIYTO-CECIDIEN or fungus galls, including the parasitic fungi which cause a metamorphosis in the shoots of larger shrubs and trees forming the structures commonly known as ' \Yitches' MORPHOLOGY OF HIGHER PLANTS. 335 brooms." Galls exhibiting strange forms are also produced by the Gymnosporangia on the stems of the common juniper, the leaves of the mountain ash, etc. In this group would also be included the CROWN-GALLS occurring on a large number of plants, as grapes, peach, juniper, and field crops. At one time it was thought that these galls were due to frosts or mechanical injuries. The extended researches of Smith (Bulletin No. 213, Bureau of Plant Industry, U. S. Department of Agriculture) have shown that crown-galls are in the nature of bacterial diseases. He showed that crown-galls not only resembled malignant animal tumors, especially sarcoma, but demonstrated that this resemblance was more than superficial. II. ZOOCECIDIEN, or those galls which are formed within the body of the plant and due to attacks by insects. This group includes by far the larger number of galls, and is further subdivided according to the various animal-groups causing them. Galls differ in structure, but the general nature of the anat- omy may be seen in a. study of the common " ink ball " or " ink gall," formed on Qiiercus cocclnca by Cynlps aciculata. These galls are produced during the summer months on the young branches and sometimes on the acorns. "When mature they fall from the trees and are nearly globular in shape, varying from 20 to 30 mm. in diameter. They are solid throughout and of the consistency of the pulp of a green apple. Externally they are smooth, and are colored a mottled green, yellow, or brownish- red. At this stage they are made up of three distinct zones : (i) A central area, made up of nearly isodiametric starch-bear- ing, parenchymatous cells. (2) The middle zone is composed of radially elongated parenchymatous cells, possessing thick, porous cellulose walls containing a lining of protoplasm and a few starch grains. With the development of the egg of the insect there also appear in the cells of this middle zone numerous starch grains closely resembling those found in the central zone. (3) An external layer made up of irregular parenchymatous cells, somewhat collenchymatic in character, with a lining of protoplasm as in the cells of the middle zone. In some studies on the origin of tannin in galls Kraemer (Bot. Gaz., 1900, p. 275) showed that in the " ink gall " there are three 336 A TEXT-BOOK OF BOTANY. stages in their development, corresponding to the life periods of the insects and changes in the constituents of the cells: (i) When the galls are first formed and the larva is beginning to de- velop, the cells of the outer zone, as well as those of the central FIG. iQ2. Transverse section of one of the collateral mestome strands of the stem of Viola tricolor arvcnis: o, portion cf cells of pericycle; e, endodermis; 1, leptome or sieve cells, in among which are some collenchymatous cells (c) ; m, cambium; t, spiral tracheae or vessels; g, strongly lignified tracheae; rp, medullary ray cells, the walls of which are com- posed of cellulose; rs, medullary ray cells the walls of which are strongly lignified; s, strongly lignified cells separating the mestome strands; c, collenchyma; p, pith. zone, contain numerous small starch grains. (2) When the in- sect reaches the chrysalis stage the starch in the cells near the middle of the galls is replaced in part by gallic acid, while the cells at the center and near the periphery contain masses of tannic MORPHOLOGY OF HIGHER PLANTS. 337 B ST 5 M W R FIG. 193. Collateral fibrovascular bundle in Menispermum: C, cortex; B, bast fibers; St, stone cells connecting groups of bast fibers; S, sieve; M, cambium; T, tracheae; W, wood fibers; R, medullary rays; P, pith. 22 338 A TEXT-BOOK OF BOTANY. acid. (3) When the winged insect is developed nearly all of the cells contain amorphous masses of tannic acid with some adhering1 crystals of gallic acid. After the insect has emerged from the gall the constituents again undergo change, depending largely on the presence of moisture, when the tannic acid is changed into more or less insoluble products and the galls become more porous. THE INNER STRUCTURE OF THE STEM. If we make a transverse section of a young herbaceous stem, we observe a differentiation of the tissues, which in several re- spects agrees with that of the root previously described. In the primary structure of the stem the following tissues are to be noticed : The outermost layer is the epidermis with a more or less distinct cuticle ; the second is the cortical parenchyma, fre- quently having strands of collenchyma near the epidermis. The cortex often contains secretory cells or receptacles, and not infre- quently the innermost layer is differentiated as an endodermis. The latter surrounds the so-called pericycle, a sheath consisting of more or less distinct stereomatic strands, either forming a closed sheath or merely representing isolated arches outside the leptome of the stele. Inside the pericycle we observe the mestome strands constituting mostly one circular band (in cross section) in the Dicotyledons and Gymnosperms. or several more or less concentric bands in the Monocotyledons. The mestome strands or fibrovascular bundles may be collateral (Figs. 192-194), bi- collateral or concentric, the last of which being found only in the Monocotyledons (Fig. 195) and Ferns (Fig. 56). In the DICOTYLEDONS the collateral fibrovascular bundles occur most frequently and consist of three distinct portions, vis., phloem, xylem, and cambium. The phloem consists of sieve tubes, com- panion cells (or accompanying cells), and cambiform. The last two are thin- walled parenchymatous cells, those of the cambiform being considerably elongated. In addition there may be included in the phloem the stereomatic tissues or bast fibers, which are not infrequently well developed. The xylem includes tracheae or vessels, tracheids, wood parenchyma, and libriform or wood fibers. To the student some confusion may arise as to the apparent indiscriminate use of the terms, leptome and hadrome, the former MORPHOLOGY OF HIGHER PLANTS. 339 FIG. 194. Dicotyledonous stem structure. Transverse section through menispermum rhizome: E, epidermis; K, sub-epidermal cork; C, cortex; B, bast fibers; S, sieve; ST, stone cells; CA, cambium; T, vessels; W, wood fibers; M, medullary ray cells; P, pith. 340 A TEXT-BOOK OF BOTANY. - s — T FIG. 195. Monocotyledonous stem structure. Transverse section of convallaria rhizome: E, epidermis; H, hypodermis composed of collenchyma; C, cortex; EN, endo- dermis; S, perihadromatic sieve; T, tracheae or vessels; P, parenchyma. The bundles are of the collateral and concentric types. MORPHOLOGY OF HIGHER PLANTS. being used as being apparently synonymous with phloem and the latter being equivalent to xylem. As a matter of fact, these terms are not equivalent, the phloem proper including bast fibers in addition to leptome ; and the xylem being composed of wood fibers in addition to hadrome ; nor is the fibrovascular bundle synonymous with mestome strand, as the former includes not only the conducting tissues but the mechanical tissues as comprised in the xylem and phloem ; while the mestome strand includes only the conducting cells comprised in the leptome and in the hadrome, there being no sclerenchymatous fibers present. The following- table will doubtless make clear to the student the relationship of these tissues to each other : Leptome or Sieve portion Mestome or vascular bundle Stereome or Bast fibers f Sieve tubes < Accompanying cells (.Cambiform Cambium Phloem TT j (Tracheas Hadrome or Tracheid3 .Tracheal portion }Wood parenchyma Libriform or Wood fibers Xylem Fibro- vascular bundle When the collateral mestome strand increases in thickness, the increase is due to the activity of the cambium, here called the INTRAFASCICULAR CAMBIUM, which then develops phloem or lep- tome out\vardly and xylem or hadrome inwardly. Between the primary mestome strands there is frequently a procambium, which connects these strands writh each other, and which gener- ally gives rise to secondary mestome strands, or the connection may be effected by means of the intrafascicular cambium, which often extends itself from one strand to another and develops lep- tome and hadrome, as in the primary strands ; such cambium is distinguished as INTERFASCICULAR CAMBIUM and is commonly referred to as the CAMBIUM RING. The BICOLLATERAL mestome strands or fibrovascular bundles, characteristic of some Dicotyledons (Labiate, Solanaceae, Cucurbi- tacea?, etc.), differ from the COLLATERAL type by having a leptome 342 A TEXT-BOOK OF BOTANY. strand developed on the inner face of the hadrome; thus each mestome strand carries two strands of leptome (Fig. 197, C). In the CONCENTRIC mestome strands the leptome may encircle the hadrome, as in the Ferns (Fig. 56), or the hadrome may partly FIG. 196. The outer bark and part of the inner bark of Rhammis Purshianus in trans- verse, radial-longitudinal, and tangential-longitudinal sections. Me, transverse section of inner bark ; Mt, tangential-longitudinal section of inner bark ; Mr, radial-longitudinal section of inner bark; Sc, transverse section of stone cell area; St. tangential-longitudinal section of stone cell area; Sr, radial-longitudinal section of stone cell area; He, transverse section of outer layers of cortex; Hr, radial-longitudinal section of outer layers of cortex. Kc, Kt, Kr, transverse, tangential-longitudinal, and radial-longitudinal sections of cork; b, bast fibers; f, crystal fibers; p, parenchyma; e, sieve; sk, stone cells; m, medullary ray cells; c, collenchyma. (as in the rhizomes of many Monocotyledons) surround the lep- tome (Fig. 195). While thus the collateral type of strand or bundle occurs in both Monocotyledons (Fig. 195) and Dicotyle- dons (Figs. 192, 193), etc., the presence of a cambium is found only in the Dicotyledons and occurs extremely seldom in the Mono- MORPHOLOGY OF HIGHER PLANTS. 343 cotyledons. The central portion of the stele is frequently differ- entiated into a PITH of parenchymatic structure, the cells of which oiten contain large quantities of starch. In addition in the pith, we often find the same types of secretory cells or receptacles as occur in the cortex (as in Apocynum). The pith may constitute a homogeneous tissue or be broken, as in Phytolacca, Carya, Halesia, etc., where a longitudinal section shows the pith divided into a row of broad cavities formed by a separation of the cells as a result of the rapid longitudinal growth of the stem. Finally it may be mentioned that cork is of frequent occur- rence, especially upon stems that persist more than one year. The cork may arise in the epidermis itself, or it may develop in the hypodermal strata of the cortex, or in still other cases we find its development much deeper, even within the pericycle. FIG. 197. Schematic representation of different types of mestome strands or fibro- vascular bundles: s, sieve; t, tracheae or vessels; e, position of the earliest tracheae formed; a, radial bundle or mestome strand; b, collateral bundle; c, bicollateral bundle; d and e, concentric bundles. — After Meyer. In regard to the increase in thickness, the stem develops much like the root, as in the throwing off the peripheral tissues extend- ing from the epidermis to the endodermis, or of the epidermis and adjoining cortex, the displaced tissues are replaced by strata of cork and secondary cortex. The mestome strands in the stern, however, grow in a more regular manner than is the case with those of the root, as is seen in the very distinct and frequently very regular layering of the tissues of woody stems, forming the so-called " Annual Rings," where each ring represents the growth that occurs during a single year. The development of these annual rings depends especially upon the fact that the growth of the perennial stem does not take place continuously, but is in- terrupted during certain periods of the season, for instance dur- ing the winter or during the dry seasons of tropical climates. And since the tissues which are formed at tHe beginning of each 344 A TEXT-BOOK OF BOTANY. season's growth are distinct from those already formed during the previous season in both color and structure of the wood (espe- cially in the thickness of cell-walls and the width of the tracheae or vessels), we perceive in this manner distinct zones of wood, or the " annual rings " as they are called, the larger vessels with thin walls being produced in the spring and early summer. Various abnormal stem-structures are known which are due pv j-s^i^i1 • .u, \^aa — if^er — (Wrii \J' FIG. 198. Transverse section of wood of Rhamnus Frangula showing that the annular rings seen in woody portion of plants is due to a difference in the nature and structure of the cells formed in the spring and in the fall. In the spring numerous large tracheae or vessels (v) are formed, whereas in the fall very few vessels and mostly wood fibers are developed, the cells of these being smaller as they approach the end of the year's growth.— After Rossmann. to certain peculiarities in the growth in thickness of stems. These are especially noticeable in lianes. In some of the Monocotyledons, as in Dracaena, Yucca, Agave and Aloe, we find a secondary in- crease in growth of the stems. In summarizing the root and stem structures of Monocotyle- dons and Dicotyledons the following general facts should be borne in mind. Monocotyledonous stems resemble Monocotyle- donous roots except that the fibrovascular bundle or mestome MORPHOLOGY OF HIGHER PLANTS. 345 strand of the former is concentric, whereas in the latter it is radial. The primary structure of Dicotyledonous roots is much the same as in Monocotyledonous roots. The primary structures of Dicotyledonous stems resemble the primary structure in Dicoty- ledonous roots except that the fibrovascular bundles of the former are of the collateral type. The secondary structures of both roots and stems of Dicotyledons are oractically alike. The characteristics FIG. 199. Section of a four-year-old stem of a pine cut in winter; q, view in trans- verse section; 1, radial-longitudinal section; t, tangential-longitudinal section; f, spring wood; s, fall wood; m, pith; i, 2, 3, 4, successive years' rings of growth in which is shown the dividing line; ms, medullary rays in transverse section; ms1, ms11, medullary rays in radial-longitudinal section; ms111, medullary rays in tangential-longitudinal section! c, cambium; b, bast; h, resin-canals; br, bork. — After Strasburger. distinguishing the primary and secondary structures of Dicotyle- donous stems may be summarized as follows : PRIMARY STRUCTURES. — Epidermis, hypodermis, primary cor- tex, endodermis, pericambium or pericycle, stele consisting of collateral fibrovascular bundles and pith. SECONDARY STRUCTURES. — Periderm derived from phellogen; secondary cortex, consisting of parenchyma and occasionally stone cells or secretory cells or vessels ; phloem consisting of sieve, accompanying cells and sometimes bast fibers ; cambium in 346 A TEXT-BOOK OF BOTANY. FIG. 200. Coarse structure of a number of woods as seen with a Coddington lens: A, English walnut (Juglans regia) showing the tracheae evenly distributed in the form of pores, which can be seen in the wood with the naked eye; the medullary rays are rather faint and arranged in closely radiating, parallel rows; in the fall wood are numerous fine transverse lines parallel with the annular markings. B, shell-bark hickory (Carya ovata) showing a row of large tracheae (g) in the summer wood and somewhat smaller tracheae (g') scattered throughout the subsequent growth; medullary rays numerous, as are also the somewhat undulating transverse lines (F). C, white or canoe birch (Betula pendula) showing distinct annular rings and numerous medullary rays between which are scattered the small tracheae indicated by black dots. D, chestnut (Castanea dentata) showing large tracheae arranged in circular groups, those of the successive layers being smaller and arranged some- what obliquely, forming triangular groups; medullary rays very faint; E, Elm (Ulmiis campestris) showing tracheae arranged in circles in the summer wood and in the later growth a number of broad more or less undulating plates composed of very small tracheae; medullary rays quite distinct; F, Cherry (Primus domestica), tracheae quite distinct in the summer wood, forming several circular rows; medullary rays broad and distinct. — B, after Wiesner; the remainder after R. Hartig. MORPHOLOGY OF HIGHER PLANTS. 347 the form of a ring known as interfascicular cambium ; xylem com posed of tracheae, wood parenchyma, usually wood hbers and sometimes tracheids ; medullary rays separating the collateral bundles ; pith composed of parenchyma and sometimes having stone cells and secretory cells similar to those found in the cortex. In stems having bicollateral bundles, strands of phloem also^ occur on the inner surface of the xylem rays. IMPORTANCE OF THE STUDY OF THE STRUCTURE OF WOOD. — The structure of stems in woody plants is very characteristic, not only in different families but in genera and at times in species. In the Pinaceae, for instance, the wood is entirely made up of tracheids, the tracheae being wanting. In most of the Dicotyledons tracheae are present, being absent only in certain water plants as Nymphaeaceae and in Drimys, a genus of the Magnoliaceae. In the Cactaceae the secondary wood is provided with annular and spiral tracheids. In practical work, whether it be in the study of plants for taxonomic purposes or for their industrial uses, the following are some of the observations that should be made : I. Structure of the walls and nature of the perforations or mark- ings in the tracheae or vessels. . 2. The presence or absence and relative distribution of libriform or wood fibers (often referred to as wood prosenchyma). 3. The structure of the medullary rays not only as regards thickening of the walls and contents of the cells, but the number of the cells both as to width and height entering into the individual groups of rays. 4. Wood paren- chyma is variously distributed, the cells aggregated about the vessels being distinguished from those that form tangential bands separating the circles of vessels. The distribution of the crystals is also of importance, as they may occur in isolated cells or in superimposed cells adjoining the wood fibers and form the so- called crystal fibers. In the study of different commercial woods it is customary in practice to study the coarser features such as can be recog- nized by the help of an ordinary hand lens. In this superficial study many distinctive characteristics can be readily determined, as the nature of the annual rings, the size of the lumina of the ves- sels, as well as their abundance and arrangement, etc. (Fig. 200). 348 A TEXT-BOOK OF BOTANY. III. THE OUTER MORPHOLOGY OF THE LEAF. Leaves are lateral formations upon the stem and their growth is definite. They never occur on other portions of the plant than stems, from the surface of which they are developed. Leaves appear in acropetal succession, so that the youngest leaves occur nearest the apex of the stem. Terminal leaves are extremely rare, but arise in some instances from the flowers of certain Euphorbiaceae. I FIG. 201. A, leaf of violet (Viola tricolor) showing broad lamina, long petiole, and one of the palmately-lobed stipules at the base of the petiole. B, C, stages in the development of the leaf. The lobes of the stipules (s) develop before the lamina (1). A Simple Leaf consists of a LAMINA or blade, which is usually membranous and of a green color, and a PETIOLE or stalk, which, however, may be wanting when the leaf is said to be sessile. Leaves may also possess a pair of leaf-like structures at the base, known as STIPULES (Figs. 201, 204). The principal function of the latter appears to be that of protecting the buds, as in the tulip poplar (Liriodendron) (Fig. 204), although they may be- come leaf-like and assist in the functions of the lamina, as in Viola tricolor (Fig. 201). MORPHOLOGY OF HIGHER PLANTS. 349 Light Relation of Leaves. — While the lamina of the leaf appears to assume a more or less horizontal position, it usually inclines at such an angle as to receive the greatest amount of dif- fused daylight. Wiesner has shown, for instance, that when plants are so situated that they receive direct sunlight only for a time in the morning, and diffused daylight during the rest of the day, the position of the upper surface is at right angles to the incident rays of daylight, and not to that of the rays of the morning sun. This phenomenon may be studied in the house geranium and other window plants. In endeavoring to explain this behavior of the leaves, Frank assumes it to be due to a kind of heliotropic irritability peculiar to dorsiventral organs, and terms it TRANSVERSE HELIOTROPISM. The stem, as well as the petiole or stalk of the leaf, is also influenced by the light, and is said to manifest positive helio- tropism. Those parts of plants that turn away from the light, as the aerial roots of the ivy, are said to possess negative helio- tropism. Depending upon their relation to external agents, several forms of leaves are distinguished. In those which assume a more or less horizontal position the two surfaces of the lamina are quite different, and the leaves are said to be DORSIVENTRAL, or bifacial. Usually there is a more compact arrangement or stronger development of chlorophyll tissue on the upper or ventral surface, while on the lower or dorsal surface the veins stand out more prominently, and there is a greater number of stomata. In contrast with this type of leaf may be mentioned those which grow edgewise and in which both surfaces of the leaf are more or less alike, as in the Eucalypts and Acacias of Australia. In Iris and Calamus, the leaf-like organ is actually not the blade, but merely a part of the dorsal face, which, in the bud, has already pushed out so as to exceed the apex. Such leaves are called SWORD-SHAPED and are frequently referred to as EOUITANT. The leaves of certain species of Juncus, Carex and some of the grasses are commonly spoken of as CYLINDRIC. Such leaves are, how- ever, only apparently cylindrical, since the ventral surface is often distinct, though much narrower than the dorsal. They are also frequently hollowr. 350 A TEXT-BOOK OF BOTANY. Functions of the Leaf. — When we speak of the leaves of the plant we usually have in mind the foliage leaves or green chlorophyll leaves. Under the influence of sunlight the chloroplasts are able to rearrange the elements in carbon dioxide and water, which are looked upon as inorganic substances, into starch or related com- pounds which are of an organic nature. This process is known as carbon dioxide assimilation, or PHOTOSYNTHESIS, which latter term means the building up of a compound under the influence of light. In this process, which is sometimes expressed by the fol- lowing formula, oxygen is given off : 6CXX + 5H20 = C6H1005 + 6O2 Carbon dioxide Water Starch Oxygen The importance of this function can be best appreciated by bearing in mind that all of the organic products built up by the plant are derived almost entirely from the carbon dioxide of the air which is taken in through the leaves. (Consult also pages 157-1590 Transpiration and respiration are also functions of the leaf. TRANSPIRATION is the giving off of water (through water-pores), or watery vapor (through the stomata), which has been absorbed by the root-hairs and transported through the tissues of the root, stem and leaf ; the process of breathing, or RESPIRATION, consists in the taking in of oxygen and giving off of carbon dioxide, the exchange being just the reverse of what it is in photosynthesis. These several functions are, however, not confined to the leaf alone, but are carried on by all the green parts of the plant. PHYSIOLOGICAL EXPERIMENTS. — The leaf is undoubtedly the most active part of the plant from the physiological point of view. Some of its activities can be demonstrated by comparatively sim- ple means. For instance, it can readily be shown, that leaves or rather chloroplastids form starch when exposed to sunlight but that no starch is formed when the light is not admitted, by a simple con- trivance called a leaf shield. This is a device by which a thin piece of glass can be clamped against the leaf. Over a portion of this glass a piece of tinfoil may be pasted, thereby shutting off the light from the underlying area. The procedure consists as MORPHOLOGY OF HIGHER PLANTS. 351 follows : On the day previous to the demonstration of the experi- ment the leaf shield is clamped on the leaf. On the following day the leaf is allowed to stand well exposed to the sunlight for several hours. The leaf is then removed from the plant, separated from the leaf shield, and after the chlorophyll is extracted by boiling in .alcohol it is placed in \veak iodine solution, \vhereby the entire part of the leaf exposed to the light is darkened in color, while the area protected by the tinfoil remains unchanged. The phenomenon of photosynthesis whereby the leaf uses carbon dioxide and gives off oxygen can be demonstrated by means of a photosynthometer. Ganong gives a detailed description of its construction and use. The underlying principle is that a known volume of leaf material is supplied with a known volume of carbon dioxide. After submitting the leaf to the sunlight a test is made of the proportion o*f carbon dioxide and oxygen in the graduated tube, from which the activity of the leaf may be accurately deduced. The process of transpiration in leaves can also be readily shown. The mere fact of transpiration can be shown by inserting the leaves of a plant into a bell-jar which has at its base a sheet of rubber or other suitable material stretched over the opening with just sufficient aperture to admit the stem. The root being outside of the bell-jar can be kept moist and as transpiration takes place the moisture condenses on the inside of the glass. By means of an arm balance and devices for measuring the water supplied the plant, together with some covering to prevent evaporation from the surface of the soil, rather accurate deter- minations can be made of the quantities of water given off by the plant and calculations made for each square unit of leaf surface. The potometer is another ingenious simple contrivance which measures most accurately the amount of water transpired. It consists of a horizontally placed graduated tube which ends in a short vertical portion into which a stem bearing leaves can be tightly inserted after the instrument is filled with water. By means of a reservoir at the side and a stop-cock more water can be admitted as needed. Accurate readings over short periods of time are facilitated by admitting a small bubble of air as an index and observing the time of its passage along the graduated tube. (Consult Ganong: Plant Physiology.) 352 A TEXT-BOOK OF BOTANY Leaf Venation.- -The foliage leaves of higher plants are traversed by vascular bundles, which enter the blade through the petiole and diverge at the base, or, as in the case of Dicotyledons, branch in various ways ; and it will be seen that the form of the leaves corresponds to the distribution of the bundles. These bundles are known as veins or nerves, and they have two func- tions, namely, (i) that of a mechanical support, and (2) that of carrying nutritive materials to and from the leaves. The mode of venation in Monocotyledons and Dicotyledons differs somewhat, but it will be found that in a number of instances FIG. 202. Leaf venation: A, parallel-veined leaf of Solomon's seal (Smilacina race- mosa); B, pinnately-reticulate leaf of chestnut; C, palmately-veined leaf of Menispermum canadense. the venation of leaves of plants belonging to one of these great groups will resemble that of the leaves of certain plants in the other group. However, there are certain general types belonging to each group (Fig. 202). VENATION IN MONOCOTYLEDONS. — An examination of the leaf of lily-of-the-valley shows that the primary veins run more or less parallel to the apex with short though distinct anastomoses. Such a leaf is said to be PARALLEL-VEINED or NERVED. It will moreover be noticed that the distribution of the veins in this manner produces a lamina with an even, or entire margin, and MORPHOLOGY OF HIGHER PLANTS. 353 such a system of venation is known as a closed system of venation (Fig. 202, A}. The leaves of Veratrum and Zea Mays furnish other examples of parallel-nerved leaves. In palms the venation is somewhat different. The veins, instead of converging toward the apex as they do in the more or less lanceolate leaf of Kly-of-the-valley, radiate from the base to the margin of the more or less round leaf, and a leaf of this type is said to be PALMI-NERVED. There is still a third type of venation in Monocotyledons. In this instance one principal vein runs from the base to the apex of the leaf, and from this branches run parallel to the margin. The banana furnishes an example of this type, and is said to be PINNI-NERVED. VENATION IN DICOTYLEDONS. — Here the veins are character- ized by their habit of repeatedly branching and anastomosing, whatever the general type of venation may be, and thus form a net-work or reticulum, hence the leaves are said to be RETICULATE or NETTED-VEINED. The principal types are as follows : A chest- nut or chinquapin leaf (Fig. 202) furnishes a good illustration of a pinnately-reticulate leaf. The principal vein which runs from the base to the apex is called the MIDRIB, while the secondary veins which arise from it and run more or less parallel to the margin are sometimes spoken of as ribs and may be likened to the plumes on the shaft of a feather. In other cases -several large veins arise at the base and diverge toward the margin, giving rise to PALMATELY-VEINED leaves, as in the leaf of maple. There are still other types, as in cinnamon, which is said to be rib-netted, etc. Surface of Leaves. — In addition to the markings of leaves due to veining there are certain other characters which serve to distinguish them. Hairs are of frequent occurrence on leaves, being generally most abundant on the dorsal surface, especially the veins, and various terms having reference to the kinds of hairs have been applied to leaves. Plant Hairs. — When the surface of the plant (either of stems or leaves) is covered with short, fine hairs, which are not very dense and not matted, the surface is described as PUBESCENT; when the hairs are relatively long but scattered the surface is said 23 354 A TEXT-BOOK OF BOTANY. to be VILLOUS; or when the hairs cover each other in one direction it is described as SERICEOUS or silky. When the hairs are stiff though slender we speak of a HIRSUTE covering; when the hairs are vernate, thickish and stiff, as in Borago, the surface is spoken of as being HISPID. If the hairs are bristle-like the surface is described as STRIGOSE ; or if they are terminated by a globular, glandular head (Figs. 100, 124), as GLANDULAR. Again, when the hairs are matted the surface is described as LANATE ; when they are long it is said to be WOOLLY; or when they are short and soft as in Mullein it is said to be TOMENTOSE. \Yhen the hairs are hard and prickle-like the surface is described as HISPID or STRIGOSE; when they are modified to spines it is said to be SPINOSE ; and when they are hooked it is described as ECHINATE. In still other cases the epidermal cells, particularly of leaves, are uneven, forming depressions and protuberances which if slight give the surface the appearance described as RUGOSE ; or if wart-like, give the appearance known as YERRUCOSE. Further- more, the veins of leaves may be quite prominent, particularly in the lower surface, and if they are much reticulated in addition, the surface is described as RETICULATE. Texture of Leaves. — Leaves also vary in texture. A thin pliable leaf is called membranous ; one which is thick and leathery, coriaceous ; and one which is thick and fleshy, succulent, as that of the century plant and Aloe (Fig. 130). Forms of Leaves.- -The leaves of plants exhibit an almost innumerable variety of forms ; even on the same plant there are not infrequently several forms, as in riola tricolor and sassafras (Fig. 203) ; even the two margins of the same leaf may vary, as in Hamamelis and Begonia, when it is known as an inequilateral or asymmetric leaf. It frequently happens that the lower leaves on a shoot are lobed while the upper ones are entire, or some of the leaves may be sessile and other petiolate. Many of the terms used in ordinary language in describing the forms of objects are applied here also, as linear, lanceolate, oblong, elliptical, spatulate, wedge-shaped, etc. APEX OF LEAF. — A number of descriptive terms are employed in describing the apex of the lamina, as ACUTE, when the form is MORPHOLOGY OF HIGHER PLANTS. 355 that of an acute angle; OBTUSE, when the angle is blunt; ACUMI- NATE, when the angle is prolonged ; TRUNCATE, when the end of FIG. 203. Variation in the form of leaves on the same plant: A, B, C, Leaves or sassafras; D, young castor oil plant showing cotyledons (t) and variously lobed older leaves. 1, lamina; p, petiole. the leaf appears to be cut off ; RETUSE, when it is slightly notched at the apex ; OBCORUATE, when the notch is pronounced ; EMAR- GINATE, when the degree of notching is between retuse and 356 A TEXT-BOOK OF BOTANY. obcordate. Sometimes the apex appears like the continuation of the midrib, when it is termed CUSPIDATE or mucronate. BASE OF LEAF. — Some of the terms used in describing the gen- eral outline, as well as the apex of the leaf, are also applied to the base, as obtuse, truncate, cordate, reniform, etc. Other terms, however, especially apply to the base, as CUNEATE or wedge- shaped; CONNATE-PERFOLIATE, when opposite leaves are con- nected at the base and surround the stem ; PERFOLIATE, when the leaf simply clasps the stem. In Monocotyledons the base of the leaf is frequently developed as a closed or open sheath, some- times provided with a membranous protuberance between the sheath and the blade, as in the LIGULE of grasses and sedges. MARGIN OF LEAF.- -The leaves of many woody dicotyledonous plants of temperate regions possess an even margin. The others, according to the degree and character of the incisions or inden- tations, are described as SERRATE, when the apex of the divisions or teeth is sharp and directed forward like the teeth of a saw ; DENTATE, when the divisions project outward; CRENATE, when the teeth are more or less rounded ; REPAND, when the margin is somewhat wavy ; SINUATE, when the wavy character is pro- nounced ; LOBED, when the incisions extend not more than half- way into the lamina, and the sinus (or hollow) and the lobes are more or less rounded ; CLEFT, when the incisions are still deeper and the sinuses and lobes are somewhat acute ; and DIVIDED ( Fig. 205), when the incisions extend almost to the midrib. Compound Leaves.- -The divisions of a parted leaf may assume the form of a simple leaf, when the divisions are known as LEAFLETS and the whole as a compound leaf. The distinction between a simple leaf and a leaflet is, that the former has a bud in the axil. The difference between the divisions of a simple leaf and those of a compound leaf is this, — in the former they never become detached from the petiole or midrib, whereas in the com- pound leaf they are articulated and drop off individually. Com- pound leaves may be divided into PiNNATELY-compound (Fig. 204) or PALMATELY-compound (Fig. 210, E), this distinction depend- ing upon whether the leaflets are arranged pinnately or palmately. A number of forms of pinnately-compound leaves are recognized. When the leaflets are all lateral (Fig. 207) the leaf is said to be MORPHOLOGY OF HIGHER PLANTS. 357 PARI-PINNATE; when there is an odd or terminal leaflet as in the locust (Fig. 204) the leaf is IMPARI-PINNATE ; when the midrib FIG. 204. Leaves having different forms of stipules (s) : A, bud-scale stipules of Lirio- dendron Tulipifera; B, thorny stipules and odd-pinnate compound leaf of the locust tree (Robinia Pseud-acacia); C, adnate stipules of rose; D, filiform stipules of the pear; E, fringed clasping stipules (ocrea) characteristic of all of the Polygonums; F, adnate stipules of clover. is prolonged into a tendril as in the garden-pea (Pisum) the leaf is said to be CIRRHIFEROUS-PINNATE. Movements of Leaves.- -The leaves as well as other organs of plants exhibit a variety of movements or curvatures in response 358 A TEXT-BOOK OF BOTANY. to stimuli of different kinds, and are said to possess the property of irritability. Movements of organs are of two general classes: (i) Those due to stimuli which originate in the plant and (2) those due to the influence of external factors. To the former class FIG. 205. Limnnphila heterophylla, a marsh-plant belonging to the Scrophulariaceae and growing in tropical Asia. The submerged or water leaves, below, are much divided and arranged in apparent whorls; while the leaves at the end of the shoot above water are entire and arranged in decussate dimerous whorls. In between occur transition forms, which are divided and variously lobed and arranged in decussate whorls. — After Goebel. belong all those movements which occur during the course of development from the young to the mature stage. These are known as growth movements or NUTATION. They are especially noticeable in tips of growing branches, which instead of growing MORPHOLOGY OF HIGHER PLANTS. 359 FIG. 206. i. Leaf, fruits and flowers of Anemone Pulsatilla. 2, Leaf, flower and fruit of Anemone pratensis. The leaves are pinnately divided, the divisions being further incised or dissected. 36° A TEXT-BOOK OF BOTANY. in a straight line, move either from one side to the other, or coil or curve about an imaginary axis. This spiral movement is known as circumnutation and is characteristic of twining stems and tendrils, as the hop vine and tendrils of Bryonia (Fig. 181). Nuta- tion curvatures are due to unequal growth on two sides of the organ and cease when there is a cessation in growth or when the plant has reached maturity. The movements of organs due to external stimuli are usually in a direction which shows a relation to the direction of the stim- ulus, as those produced by gravity and light (Fig. 207), and these PK . " ; FIG. 207. American senna (Cassia marilandicd) . The figure at the left shows the pin- nately-compound leaves in the day position when under the influence of light, and the one to the right the drooping position of the leaflets at night. movements are of use in bringing the organs into more favorable positions for growth. Stimuli of this kind are spoken of as orienting or TROPIC. The compound leaves of a number of plants exhibit in addition certain variable and periodic movements, which have their origin in a special mechanism known as the PULVINIS. The pulvinis appears as a swelling on the petiole and consists of parenchymatous tissue which is highly turgid, i.e., full of water. Any stimulus, such as mechanical shock, which causes a differ- ence in the degree of turgidity on two sides, will result in a move- ment of the leaves in such plants as Mimosa, Oxalis and locust. The leaves of Mimosa pudica, a common cultivated sensitive plant, show a very rapid response to such stimuli, the leaflets folding MORPHOLOGY OF HIGHER PLANTS. 361 together and the petiole and petiolules drooping. In other cases there is a change in the position of the leaves following the alter- nations of day and night. During the day the leaflets are spread out freely, but at night or in darkness they droop and fold together. These are spoken of as nyctinastic (nyctitropic) or ' sleep movements," and are exhibited by a number of leguminous plants, as clover, bean, Cassia (Fig. 207), and by wood-sorrel (Oxalis Acctosella) and various cultivated species of O. rails. The leaves of Oxalis as well as of some other plants fold together II FIG. 208. So-called carnivorous plants. I, the pitcher plant (Sarracenia purpurea) showing the modified pitcher-like leaves (A) with inflated portion which narrows into the petiole, and a terminal, more or less spreading winged portion; and a flower and flower-bud (B). II, three species of sundew: A, Drosera rotundifolia; B, D. intermedia; C, D. longifolia. — I, after Gray; II, after Drude. under the influence of intense light as well as at night or when the amount of light is reduced. Of special interest also are the lateral leaflets of Desmodium gyrans (telegraph plant) which describe curvatures at more or less regular intervals day and night when the temperature is favorable. The leaves of the sundew (Drosera) are remarkable for their sensitiveness to touch. The upper surface and margin are provided with peculiar hairs or 362 A TEXT-BOOK OF BOTANY. tentacles (Fig. 208, //) which when touched, .as by an insect, gradually curve inward. Not only this, the stimulus may be trans- mitted to other tentacles and sometimes even the blade itself may FlG. 209. Flowering plant of Venus's Flytrap (Dionaa muscipula) of North Carolina, showing the sensitive armed leaves both open and closed, in one of which an insect has been imprisoned. — Drawn from nature by Florence Newton. roll inward to some extent, thus entrapping small insects which serve as food to the plant. The leaves of a related plant Dioncea are even more sensitive and when special hairs on the blade are touched that part of the lamina bearing these hairs closes with a MORPHOLOGY OF HIGHER PLANTS. 363 quick, trap-like movement, imprisoning its insect prey (Fig. 209). Phyllotaxy, or phyllotaxis, is the study of the distribution of leaves upon the stem, and of the laws which govern it. If we examine germinating plants of the beech, the elm, or the oak, we observe that, while the seed-leaves are opposite to each other, the subsequent leaves are arranged according to a different order in these several plants, but in a definite manner in each. In the elm, the distribution of the leaves is such that the third leaf is directly above the first; in the beech, the fourth leaf is above the first, and in the oak, the sixth leaf is above the first. If these leaves are con- nected in the order of their development, it will be seen that they describe a spiral in their arrangement, and it will also be found that one or more circuits of the stem are made between the super- imposing leaves. Furthermore, it will be found that this arrange- ment constitutes a mathematical series which may be expressed in degrees, or the parts of a circle that the leaves are from each other, this measure being known as DIVERGENCE; or by the number of perpendicular rows of leaves on the stem, which are known as ORTHOSTICHIES. The following may serve to illustrate the terms used : LEAVES. DIVERGENCE. ORTHOSTICHIES. Degrees. Parts of a Circle. Elm 1 80 1 2O 144 1 * 1 Distichous Tristichous Pentastichous Beech Oak If we examine the fractions used, we will find that the numer- ator indicates the number of turns around the stem before encoun- tering a superimposed leaf, and that the denominator indicates the number of leaves found ; the latter also expresses the number of orthostichies. On adding the numerators and denominators of any two successive fractions, a fraction is obtained which ex- presses the next highest arrangement, as In quite a number of plants two leaves arise at the nodes, as in the Labiatae. These are invariably situated opposite each other 364 A TEXT-BOOK OF BOTANY on the stem, and the successive pairs alternate with one another, forming the decussate arrangement of leaves (Figs. 180, 181, 184). Modified Leaves. — Leaves are variously modified and serve for other purposes than those already described. They may be fleshy in character and serve as storehouses for nutritive material, as the seed-leaves of the oak, or they may serve for the stor- age of water, as in Agave, Aloe and succulents. In some instances, particularly when situated near the flowers, they lose their green color, as in the dogwood, skunk cabbage and others. In other cases they are modified so that they serve as a trap for insects, as in Dioncca, Sarracenia and Droscra (Figs. 208, 209). The peti- ole may become enlarged and perform the functions of the leaf, as in the Acacias of Australia; or it may become bladder-like and serve as a means for floating the plant, as in the water hyacinth. The stipules may likewise be modified, becoming leaf-like, as in the pansy (Fig. 201 ) ; or metamorphosed into thorns, as in the locust ; or clasping, as in Polygonum. In some cases the leaves are very much reduced, their functions being performed by the stem, as in Cactacese, or even by the roots, as in some orchids which have assimilating roots. Prefoliation or vernation is the disposition of leaves in the bud. The terms used to describe the folding of the leaves in the bud are derived from an examination of transverse sections of the bud. The following are some of the terms which are em- ployed: CONDUPLICATE, when the lamina of the leaf is folded lengthwise along the midrib so that the two halves of the upper surface lie together, as in the Magnoliacece; PLICATE or plaited, when the lamina is folded along the veins, like a closed fan, as in the maples ; CONVOLUTE, when rolled lengthwise and forming a coil in cross section, as in the Rosacecc; INVOLUTE, when both mar- gins are inrolled lengthwise on the upper surface, as in the violets ; KEVOLUTE, when both margins are inrolled lengthwise on the lower surface, as in Azalea. In addition, there are several terms used which are derived from the appearance of the bud, as RECLINATE or inflexed, when the upper part is bent on the lower, as in Liriodendron ; and CIRC i NATE, when the upper part is coiled on the lower so that the tip of the leaf is in the center of the coil, as in the ferns. MORPHOLOGY OF HIGHER PLANTS. THE INNER STRUCTURE OF THE LEAF. 365 In all green leaves the typical structure is as follows : A cuticle covers the outer cell-wall of the epidermis, while the epidermis itself shows much of the same modifications as exist in the stem ; frequently the lumen of the cells of the epidermis is wider on the FIG. 210. Group of transplanted wild plants showing variation in form of leaves. A, Cinnamon fern (Osmunda cinnamomea) showing sporophylls (fertile leaves) and a cluster of pinnatifid sterile leaves, the pinnae being linear-lanceolate and deeply pinnatirid; B, wild ginger (Asarum canadense) showing basal, reniform, long-petiolate leaves with cordate base and slightly pointed apex; C, young hickory (Hicoria ovata) showing the odd-pinnate (imp-?ri pinnate), 5- to 7-foliate leaves; D, ternate, decompound leaf of Virginia grape fern (Botrychium virginianum); E, digitately compound leaves of cinquefoil (Potentilla). ventral face than on the dorsal. Hairs abound on the leaves in many plants, and stomata are especially frequent on the dorsal surface. The upper epidermis may further be characterized by the presence of water-pores, the origin and function of which have already been described (Fig. 147). 366 A TEXT-BOOK OF BOTANY. The green chlorophyll-bearing tissue is called CHLORENCHYMA (frequently spoken of as mesophyll), and is frequently differen- tiated into a ventral PALISADE TISSUE, composed of long cells which are placed vertically to those of the epidermis ; and a DORSAL PNEUMATIC TISSUE, made up of irregularly branched or lobed cells with very large intercellular spaces. Secretory cells or receptacles occur in the chlorenchyma of many plants and corre- spond with those found in the cortex of the stem. When the palisade tissue occurs on both faces of the leaf blade with the pneu- FIG. 211. Transverse section of midrib of leaf of stramonium: EU, upper epidermis; CO, collenchyma; PA, palisade cells; O, layer of cells containing rosette aggregates of calcium oxalate; M, loose mesophyll; EL, lower epidermis; OP, prisms of calcium oxalate; OS, sphenoidal micro-crystals of calcium oxalate; ST, stoma; T, tracheae; SU, leptome or sieve on upper side of tracheae or vessels; SL, sieve on lower side of tracheae, this arrange- ment of leptome or sieve and tracheae forming bicollateral fibrovascular bundles. matic tissue in the center, the leaf is called " unifacial " or " iso- lateral ' (Figs. 211, 215) ; otherwise the leaf is said to be 'bi- facial " or " dorsiventral," i.e., with two distinct surfaces. Mechanical tissues, as collenchyma and stereome, are frequent and these accompany the veins as hypodermal strands, being best developed usually on the dorsal face of the latter, as underneath the leptome. The mestome-strands of the leaf blade generally lie in a single plane. They are collateral and have the leptome situated towards the dorsal face. They are nearly always sur- MORPHOLOGY OF HIGHER PLANTS. 367 rounded by thin-walled PARENCHYMA-SHEATHS, or as in several grasses and sedges by thick-walled mestome-sheaths. In some plants of various families, the midrib is not only stronger devel- FIG. 212. Study of the stomata on leaves of Beta vulgaris: A and B, surface sections of the leaf, and C and D, transverse sections of the stomata. In A and C, the stomata are shown with the guard cells (s) distended and the pore (sp) open to allow the passage of vapors and gases. B and D, showing the pore or opening closed due to the plasmolysis of the contents of the guard cells, the internal pressure or tension having been relieved. e, epidermal cells; a, large cavity or intercellular space beneath stomata; and m, loose mesophyll cells with chloroplasts. — After Frank. oped than the lateral veins, but it may be composed of several, instead of only one, mestome-strand, sometimes representing a true stele. 368 A TEXT-BOOK OF BOTANY. The petiole generally shows the structure of the midrib as far as concerns the mestome-strands, but possesses furthermore a more or less strongly developed parenchyma, the cells of which FIG. 213. Development of stomata on leaves of Sedum purpurascens: in A very early stages of growth, and B nearly completed stoma. In B are shown a stoma with two guard cells, three neighboring cells and two of the epidermal cells (e) ; the numbers in B correspond to those in A and show the origin of the several cells from the division of a single epidermal cell. — After Sachs. are colorless, thin-walled and which may often be traced to the leaf-blade itself, where it surrounds the stronger veins, causing FIG. 214. Transverse section through a stomata showing how by a slight difference in the tension the pore is either opened or closed; the dark 'lines show contour of cells when open, the light lines show when they are closed. — After Schwendener (See Haberlandt, Physiologische Pflanzenanatomie). them to project as ribs and to be much thicker in cross-section than the adjoining chlorenchyma. From a histological point of view the leaf structure of MORPHOLOGY OF HIGHER PLANTS. 369 Dicotyledons resembles very closely that of the Monocotyledons, except that in the latter the palisade-cells often radiate towards the center of the mestome-strands. There are, however, many instances of a similar development in the leaves of Dicotyledons. Abnormal structures are common in leaves, especially in such FIG. 215. Transverse section of leaf of Phytolacca decandra showing upper epidermis (ue), palisade cells (p), raphides (r), spiral tracheae (v), loose mesophyll (m) with large intercellular spaces, and lower epidermis (le) with a stoma. as are not held in a horizontal position, but vertical, as those of Eucalyptus, the Irideae, etc. The Epidermis forms the surface of the leaf and may con- sist of one or more layers of cells. The outer walls are cutinized, and when nearly smooth the leaf is said to be GLABROUS. They may be covered or whitened with a bloom, as in magnolia, when 24 3/o A TEXT-BOOK OF BOTANY. the leaves are spoken of as GLAUCOUS. In other cases the outer walls of the epidermal cells are modified to hairs (Figs. 100, 124, 125, 148-155). ANATOMICAL DIFFERENCES IN LEAVES.- -The walls of the epidermal cells, although usually isodiametric, are often very zig-zag in outline. In size, the upper epidermal cells are usually larger in a given species than those of the lower surface, and sometimes are rather linear, resembling a palisade layer. The FIG. 216. A, transverse section of leaf of Lobelia inflata showing the large irregular epidermal cells (e), palisade cells (p), trachea (t), loose parenchyma (m), and lower epider- mis (i). B, transverse section of leaf of Matico showing oil-secretion reservoir (o), upper epidermis (e), lower epidermis (1), with non-glandular hairs (h), palisade layers (p), loose mesophyll (m). cuticle may be thin or leathery and tough, and sometimes is pro- vided with minute ridges or crests, especially on the under sur- face, thereby giving a dull appearance to the leaf. Many leaves, too, excrete wax on the surface and consequently have a glaucous or hoary appearance, notably some of the poppies, the common jewel-weed and many others. Other modifications may have to do with the gelatinization of the epidermis of the leaf, assisting in the storage of water, as in the leaves of the violets. The differentiation in forms of calcium oxalate crystals is also im- MORPHOLOGY OF HIGHER PLANTS. portant in distinguishing plants that resemble each other. The size and number of stomata as well as their distribution and arrangement with respect to each other varies in different plants. For example, in certain saprophytic or submerged plants the num- ber of stomata is greatly or even completely reduced, and when pres- ent are quite functionless. Sometimes the stomata are depressed FIG. 217. Transverse section of leaf of Matico near two veins; showing the upper epidermis of several layers (e), two layers of palisade cells (p), tracheae (t), sieve (s), collen- chyma (c), loose parenchyma containing crystals of calcium oxalate (ca), and non-glandular hairs (h). below the surface of the leaf, this being true in plants occurring in dry or cold districts, and is distinctly characteristic of many Coni ferae. There is a marked difference in the arrangement of the pali- sade tissues, the following types being distinguished : I. In bifacial A TEXT-BOOK OF BOTANY. N FIG. 218. Digitalis leaves: A, transverse section near one of the veins showing the separated or extra-epidermal layer occurring on the lower surface (S) with two non-glandular hairs (N) and glandular hair (G), epidermal layer (E), lower epidermis (LE), chlorophyll layer (M), upper epidermis (UE), and tracheae (T). B, transverse section of portion of leaf showing the separated or additional epidermal layer; c, collenchyma. or dorsiventral leaves the palisade cells are distributed only below the upper epidermal layer (Figs. 211, 215). 2. In unifacial or MORPHOLOGY OF HIGHER PLANTS. 373 isolateral leaves the palisade cells occur beneath the epidermal layers of both leaf surfaces, as in senna. 3. In some leaves, as in Eucalyptus, the entire parenchyma is made up of palisade cells. 4. In a few leaves there is no differentiation of a palisade layer, and these are sometimes referred to as centric leaves. The palisade cells may contain not only chloroplastids but crystals of calcium oxalate (Fig. 215), tannin-inclusions (Fig. 114), etc. Distributed among the palisade cells may be the oil-secretion reservoirs (Fig. 216, B). Furthermore, the palisade cells may be of equal length or the stratification may be quite uneven and irregular. In shape they may vary from long, narrow cells to short, broad cells. In some special instances they are narrowed at the lower end in the form of a blunt cone forming the so-called ' funnel cells," which are especially characteristic of plants in- habiting moist localities. There is still another common form known as arm-palisade parenchyma, in which the cells are branch- ing and connected with each other by means of the branches. Tissues of this type occur in the Equisetaceae, Filices, Conifene, Gramineae, and in a number of Dicotyledons, such as Aconitum, Adonis, Anemone, Caltha, Clematis, Delphinium, Nigella, Paeonia, and Trollius in the Ranunculaceae ; Sambucus and Viburnum in the Capri foliaceae ; Lysimachia and Trientalis in the Primulaceae. The spongy tissue or dorsal pneumatic tissue shows consider- able variation in the arrangement and shape of the cells. In some leaves the cells are arranged in strata or layers, while in others they are more or less irregular. The cells may be spherical or provided with a number of arms, the latter developing parallel to the surface of the leaf or radiating in any direction, thus caus- ing a variation in the nature and size of the intercellular spaces. In some instances there are included in the mesophyll certain mechanical cells, of which the simplest are like ordinary stone cells. They may be more or less elongated or branched or even quite fibrous, and are known as SPICULAR CELLS. The latter are sometimes quite prominent when they traverse the leaf in a verti- cal direction, giving rise to translucent spots. Spicular cells have been found in the mesophyll of quite a number of families. They are quite characteristic, although absolutely not constant, in the ^genuine tea leaf (Thea sincnsis). 374 A TEXT-BOOK OF BOTANY. IV. OUTER MORPHOLOGY OF THE FLOWER. It is well known if the stem of a plant, as the carnation, rose, geranium, etc., be cut into pieces so that each portion has at least one node and placed under suitable conditions for growth, roots will arise from the nodes that are in the ground and a new plant will be developed. The same result can be achieved if plants like Ficus, growing in a greenhouse, have placed around the nodes near the tip of the branches a clump of sphagnum, and if the latter be kept moist roots will arise from the joints. This method of • increasing the number of individual plants, while it is limited to certain perennials and cannot be followed with annuals or bien- nials, is frequently resorted to by horticulturists, and is known as vegetative propagation. The production of independent plants in this manner is dependent upon the property of the meristematic cells in the pericycle of the stem to produce the meristems that give rise to the tissues of the root. As this process of propagation for plants growing in temperate regions and in cold climates would be more or less uncertain for the perpetuation of the species, it is fortunate that in Nature safer methods of reproduction are followed, depending upon the development of flowers and the production of seed. In the latter there is a young plant with all of the elements of root and shoot contained therein and so pro- tected by a seed-coat that it may withstand extremes of climatic conditions, as well as the various hostile forces to which it might be subjected. THE FLOWER is a shoot which has undergone a metamorphosis so as to serve as a means of propagating the individual. It is an unbranched and definite shoot, or an apex of a shoot. It might be termed a "dwarf-branch' that dies and drops off the plant after the maturation of the fruit. The most complete flower has four kinds of leaves: sepals, petals, stamens, and carpels. The sepals, usually green and leaf-like, make up the outer spiral known as the calyx. The petals being frequently highly colored form an inner spiral known as the corolla. The stamens are the polliniferous organs of the flower, and the carpels bear the ovules which later develop into seeds. While the flower is a very complicated structure in many MORPHOLOGY OF HIGHER PLANTS. 375 cases, the definition given it by some writers is very simple. It is defined as a branch which bears sporophylls. As we have seen, a sporophyll is a leaf which bears sporangia. According to the definition given, the strobiles or cones of the Gymnosperms and certain Pteridophytes, as the horsetails and club mosses, are entitled to rank as flowers. In Angiosperms other leaves may be present, and these are known as the FLORAL LEAVES. The flower, then, in Angiosperms is made up of sporophylls which are essential, and floral leaves which may or may not be present. But in speaking of the sporophylls of the flower in Angiosperms it is customary to use terms which were applied to them before their relation to the similar organs in the Gymnosperms and Pterido- phytes was understood. Thus the microsporophylls, as already pointed out, are known as STAMENS,, and the megasporophylls as CARPELS. For a great many years botanists taught that the stamens and carpels are transformed foliage leaves, — in other words, that they are derived from foliage leaves, — but in more recent years the view has been established that they arise as independent members, — are, in fact, as independent as the foliage leaves themselves. Various transformations or modifications may and do occur, but these are not confined to the foliage leaves alone, for under cer- tain conditions the sporophylls may assume the character of floral leaves. It is true that in the case of some ferns the sporophylls bear a strong resemblance to foliage leaves, as in Dryopteris Filix-mas (Fig. 53), but this does not necessarily prove that the sporophylls of Angiosperms are transformed leaves, but only that the further back we go, the less the degree of differentiation of parts until we reach the unicellular alg?e. The flowers of the Angiosperms differ from those of the Gymnosperms in that the ovules (megasporangia) are enclosed, before pollination, in an ovary which has developed a special organ — the stigma — for the reception of the pollen grains (micro- spores), and the floral envelopes are much more conspicuous. The several parts of the flower are arranged more or less compactly at the terminus of an axis known as the flower branch, the special portion bearing these parts being known as the TORUS 376 A TEXT-BOOK OF BOTANY. (sometimes spoken of as the receptacle), and that portion below the flower proper as the flower stalk (Fig. 78, PE). The carpel or carpels occupy the terminal portion of the branch, while the stamens and floral leaves occur in circles or whorls below. Pistil.- -There may be only one carpel present in a flower, or there may be more. In the latter case the carpels may remain distinct or they may be united, but, whatever the number or the degree of union, it is the carpel or carpels which constitute the closed structure known as the pistil. The pistil is usually differ- entiated into three quite distinct regions: (i) A lower bulbous portion which contains the ovules, known as the OVARY; (2) a neck-like portion known as the STYLE; and (3) at the top of the style a specialized portion which receives the pollen, known as the STIGMA (Figs. 78 and 219). When the pistil is made up of a single carpel it is said to be SIMPLE, and when composed of more than one carpel it is called COMPOUND. The carpels in the compound pistil appear to be united in different ways. Sometimes they appear to have coalesced or grown together at the margins, thus forming an ovary with but one chamber or compartment ( Fig. 223, B ) . In the other cases the carpels appear as though they were incurved or folded together at the margins along the line of union, thus forming septa or walls which divide the inner cavity into several compartments or locales (Fig. 223, A, C). When the carpels are not united but remain separate, there are as many pistils as carpels, as in the flowers of buttercup (Fig. 223, D). Thus a unilocular ovary may belong to a simple or com- pound pistil. GY.VKCIUM. — The aggregate of pistils in a flower constitutes the gynrecium. If the gyn?ecium is made up of a number of simple pistils, as in the flower of buttercup (Fig. 223, D), it is said to be APOCARPOUS. But if the carpels are united into one structure, then the gynsecium is said to be SYNCARPOUS, as in the orange flower, which is in reality equivalent to a compound pistil. Inasmuch as the styles and stigmas are frequently not united, the expression compound ovary is usually employed. According as the gynse- cium consists of one, two, three, or many carpels, it is said to be monocarpellary, dicarpellary, tricarpellary, or polycarpellary. MORPHOLOGY OF HIGHER PLANTS. 377 The pistil of the flower of the pea is simple and has an elon- gated ovary, and upon dissecting the ovary and also making a transverse section of it, it is observed that the ovules are borne upon the part which projects from the concrescent margins into the cavity, this part being known as the PLACENTA, and the united FIG. 219. Pistils and different kinds of stigmas. A, simple (monocarpellary) pistil of willow with lobed stigma; B, compound pistil of Fourcroya with head-like stigma; C, longitudinal section through flower of Spondias with five separate styles and stigmas, only three of which are shown; D, flower of Peperomia showing bristly stigma; E, recurved, thread-like stigmas of the Upas-tree (Antiaris} ; F, flower of a Canary grass showing the two simple plumose stigmas; G, pistillate flower of couch grass showing the two compound plumose stigmas; H, thread-like stigmas of pistillate inflorescence of EuMcena one of the grasses; J, tri-parted stigmas of the pistillate flower of the castor-oil plant; K, L, two forms of stigmas of Begonia. — After Engler. margins of the carpel forming the " inner" or VENTRAL SUTURE. In the syncarpous gynsecium the ventral suture of the carpels is directed toward the axis of the flower ; in some cases that portion of the carpel corresponding to the midrib is very prominent, as in the Papilionatae, and has received the name of ' outer ' or DORSAL SUTURE. There are as many locules in the ovary as there are carpels, 378 A TEXT-BOOK OF BOTANY. and the walls or partitions between the locules of a syncarpous gynsecium are known as DISSEPIMENTS; when three or more carpels are united the number of dissepiments corresponds to the number of carpels. It sometimes happens that a partition or wall is intruded from the mid-vein of the carpel, dividing a unilocular ovary into one that is bilocular, as in species of Astragalus, and such a partition is termed a FALSE DISSEPIMENT. When no other than the true dissepiments exist in the syn- carpous gynaecium the placentas are borne along the axis of the flower and are termed axial placentas. In the Caryophyllaceae the ovules are borne upon a central axis, and the dissepiments having been absorbed by the gynaecium is said to possess a free central placenta. In other cases the placentas grow backward from the central axis toward the mid-vein of the carpel, carrying the ovules \vith them, when they are spoken of as parietal pla- centas, as in colocynth fruit and watermelon. The STYLE not only varies in shape and size but in the manner of attachment to the ovary (Fig. 219) ; it may be very short, as in the clove; long and filiform, as in (Enothera; club-shaped (clav- ate), as in the orange; or broad and petalloid, as in Iris. It is usually situated at the summit of the ovary, when it is said to be apical or terminal ; it may, however, be laterally attached, as in the strawberry, or, as in a few instances, attached to the base of the ovary. It is usually smooth, but may be hairy, as in the Com- positae. The styles, like the carpels, may be separate or united, and in the latter case may have a central canal connecting the stigma with the ovary, as in the violets. While usually deciduous, the style may be more or less persistent — forming a part of the fruit — or even become much elongated, as in the dandelion. •The STIGMA is an essential part of the pistil in that it is the germinating surface for the pollen grains, it being viscid and espe- cially adapted for this purpose (Fig. 219). The stigmas may be separate, as in the Composite, or they may be united into a more or less club-shaped or globular head, consisting of as many lobes as there are stigmas, as in the poppy. The stigma, while usually solid, may have an opening, as in the violets, which sometimes has a lid-like appendage, as in Viola tricolor. The OVULES (Fig. 219), as we have already seen, are small MORPHOLOGY OF HIGHER PLANTS. 379 bodies which are borne on the placentas, and which, after fertiliza- tion, develop into seeds. The number of ovules varies considerably — there may be but one, as in the almond, or there may be a large number, as in the watermelon. There are several principal forms of ovules (Fig. 220) recog- nized, of which the following may be mentioned : ( I ) ATROPOUS, in which the ovule is straight and erect on its stalk, as in the Urticacese 5(2) ANATROPOUS, in which the ovule is bent over on to the stalk so as to be in an inverted position, the line of attachment of the ovule and stalk being known as the raphe (Fig. 230, n) ; (3) CAMPYLOTROPOUS, in which the ovule is bent upon itself, as in Stramonium, this form being less frequent than the other two. Most of the ovules of flowering plants are anatropous. FIG. 220. Three positions of ovules. A, atropous; B, anatropous; C, campylotropous. (f) funiculus or stalk; (c) chalaza, or point of union of nucellus and integuments; (k) nucellus or megasporangium; (em) embryo-sac or megaspore; (ai) outer integument; (ii) inner integument; (m) foramen or orifice for entrance of pollen tube, known as the micropyle in the seed ; (r) raphe. — After Prantl. Stamen. — As already indicated, the stamen consists of a stalk-like portion called the FILAMENT, and a specialized portion which bears the sporangia, called the ANTHER (Fig. 78). The filament may be long or short or wanting. It is commonly thread- like, but varies considerably, and is sometimes leaf-like. The ANTHER is the essential part of the stamen (Fig. 221) and consists of two lobes, each of which is composed of two divi- sions or pollen sacs (Fig. 79). These sacs contain the pollen, which is commonly discharged either through a longitudinal suture or line of dehiscence, or through an opening at the tip. The anthers may be variously attached to the filament (Fig. 221). When they face the axis of the flower they are said to be INTRORSE, as in the Violacese, and when they face the perianth they are said 38o A TEXT-BOOK OF BOTANY. FIG. 221. Different types of stamens. Abbreviations: filament (f), pollen sacs or bheca (sporangia) (th), connective (c). A, stamens of a water lily (Xymphcca) showing variation in the stamens (a-d); B, theca near middle of the stamen otPopowia; C, anther of another species of Popowia with fleshy connective and pollen sacs on either side; D, stamen of Tradescantia with transverse connective; E, F, G, stamens of several Commclinacecs with broad connectives; H, stamen of Salvia with peculiar swinging connective and an aborted pollen sac or staminodium (std) at the lower end and the fertile pollen sac above; J, peculiar elongated connective of Uno'na; K, elongated connective of Humiri; L, androe- cium of violet showing two spurred sessile stamens; M, stamen of Coliimelia with sinuous confluent anthers, broad connective and short filament; N, confluent transverse pollen sacs of Arisarum; O, united pollen sacs of Columbine showing small connective; P, spherical pollen sacs of C"a//a,with slightly developed connective; Q, versatile anther and long, slen- der filament of dead nettle (Lamium album); R, dehiscence of anther of Soianum by means of terminal pores; S, spurred anther of Arbutus with terminal pores; various kinds of val- vular dehiscence, as in Berberis (T), Atherosperma (U) and Persea (V). — A, after Caspary; B, H-R, U, V, after Baillon; S, T, after Sachs; D-G, after Schonland. to be EXTRORSE, as in the Magnoliacese ; when they lie horizontally on the tip of the filament, so that they swing" as on a pivot, as in the tiger lily, they are said to be VERSATILE ; when they adhere MORPHOLOGY OF HIGHER PLANTS. 381 longitudinally to the sides of the filament and the dehiscence is marginal, they are said to be INNATE; when they adhere longi- tudinally to the filament and the latter extends slightly beyond them, they are said to be ADNATE, in which case they may be extrorse or introrse. In some of the Labiatae the lobes of the anther are united at the apex of the filament, but diverge from the point of attachment and are said to be connate, coherent, or CONFLUENT. The CONNECTIVE is that portion of the filament to which the lobes of the anther are attached or which connects them (Fig. 221 ); usually it is not very prominent ; but in some of the Labiatae, as in Salvia, it is rather broad ; in some of the Malvaceae it is entirely wanting, the two lobes being confluent ; in other cases it may be extended beyond the lobes of the anther, as in species of Asarum. APPENDAGES OF ANTHER. — In certain instances the anthers are appendaged (Fig. 221) : In the violets there is a triangular growth at the apex ; in the oleander the apex is plumose ; in deer berry (Vaccinium stamineum) there are two awn-like append- ages upon the back of the anther; in the violets the two stamens that project into the spurred petal are also spurred and secrete a nectar; in the Asclepiadaceae the anthers possess wing-like ap- pendages, each sac or division of which contains a pear-shaped coherent mass of pollen grains (pollinium). When a flower has but one stamen it is termed MONANDROUS ; and when there are two, three, or many stamens, it is said to be diandrous, triandrous, or polyandrous (Fig. 223). The aggregate of stamens in the flower is called the ANDRCECIUM. In the Labi- atae there are four stamens arranged in a longer and shorter pair, and the stamens are said to be DIDYNAMOUS ; in the Crucif erae the flowers possess six stamens, four of which are longer than the other two, and the stamens are described as TETRADYNAMOUS ; in some plants, as in the Lobeliacese, Papilionatae, etc., the fila- ments cohere, forming groups (Fig. 222) which are termed mona- delphous, diadelphous, etc. ; in the flowers of the potato the anthers lie close together but are not united, forming apparently a continuous ring or band around the pistil, when they are said to be connivent ; in the tubular flowers of the Composite the 382 A TEXT-BOOK OF BOTANY. anthers are united, forming a closed ring, and the stamens are spoken of as SYXGENESIOUS (Fig. 222, A) ; in many of the Cucur- bitacea? the filaments and anthers both are confluent ; in the flowers of the Orchidacese the stamens are borne upon the pistil and are said to be GYXAXDROUS. Floral Envelopes. — As their name indicates, the floral en- velopes occupy the outermost or lowest position in the arrange- ment of the parts of the flower. In the bud condition they protect the essential elements, and in the expanded flower are considered to play an important role in securing pollination through the visitation of insects. The floral envelopes are made up generally of two kinds of leaves, petals and sepals (Figs. 224 to 227). FIG. 222. Union of stamens. A, united anthers of flower of Compositae; B, diadelphous stamens of Pisum with i free stamen and 9 united; several types of monadelphous stamens, as in Erythroxylon (C), Melia Azedarach (D), and common mallow (E). — After Baillon. The PETALS form a spiral which surrounds the andrcecium. They are, as a rule, quite bright and attractive, being frequently highly colored, as in the rose, Fuchsia, violet, etc., and are known collectively as the COROLLA. The SEPALS form the next and lowermost spiral. They are usually green and leaf-like, as in the rose and carnation, and together constitute the CALYX. Sometimes the corolla and calyx are spoken of together as the PERIAXTH, although, strictly speak- ing, the term has a more special application, and is used mostly in speaking of the sepals and petals of monocotyledonous flowers, MORPHOLOGY OF HIGHER PLANTS. 383 these parts being much alike and not distinguishable, save in posi- tion, as in certain lilies. B FIG. 223 Types of flowers: A, hypogynous flower of flax; B, perigynous flower of cherry, showing perianth tube with sepals, petals and stamens on its border; C, epigynous flower of American sarsaparilla ; D, flower of buttercup showing apocarpous gynaecium and large conical torus; E, irregular (bilateral or zygomorphic) flower of aconite showing half of helmet-like sepal (a), other sepals (b, c), long-clawed nectary (k) developed from one of the posterior petals, separate pistils (f); F, corolla of Salvia spread open and showing the two rudimentary stamens and two fertile stamens. The connectives in the latter are long and filamentous and each bears at the upper part a normal pollen sac and at the lower end a non-fertile enlarged portion which the insect pushes against in entering the flower and thus causes the pollen to be deposited on its back. — A-C, aftei Gray: D-F, after Warming. When the divisions of the calyx and corolla remain separate and distinct the latter are spoken of as CHORISEPALOUS and CHORI- PETALOUS, respectively; but when the divisions are united or 384 A TEXT-BOOK OF BOTANY. FIG. 224. Lobelia inflata: A, upper portion of shoot showing the dentate-denticulate leaves, the bracted racemes with flowers and inflated capsules, the latter developing soon after fertilization; B. flower showing linear calyx teeth and 2-lipped corolla, the upper lip with 2 rather erect lobes and the lower lip spreading and 3-cleft; C, longitudinal section of flower showing the ovary with ovules (o), style (s), hairy bifid stigma (t) , united stamens (a), corolla (p) and calyx (c) ; D, longitudinal section of stamen showing the hairy summit. Scutellaria pilosa: E, branch showing crenate leaves and helmet-shaped capsular fruits; F, capsule after dehiscence showing nutlets (n). G, section of flower of Scutellaria lateri flora showing calyx (c) with crest on one side, 2-lipped corolla (p), the didynamous stamens (s), and 4-locular ovary (n). Spearmint (Mentha spicata): H, showing flowers in slender interrupted spikes; J, flower with bell-shaped calyx, tubular corolla and 2-lobed stigma; K, ellipsoidal pollen grains. MORPHOLOGY OF HIGHER PLANTS. 385 coalesced the calyx and corolla are called GAMOSEPALOUS (syn- sepalous) and GAMOPETALOUS (sympetalous), respectively. When the divisions of the calyx or corolla are entirely united these elements are said to be ENTIRE, and when the divisions are FIG. 225. Flowers of Solanaceae. Solanum carolinense: A, portion of shoot showing a short raceme of flowers and the spinose leaves and stems; B, diagram of cross section of flower showing sepals (s), petals (p), stamens (a) and ovary (c) ; C, longitudinal section of flower, the letters the same as in B; D, stamen showing terminal pores; E, two spheroidal pollen grains; F, cross section of 2-locular berry. Hyoscyamus muticus: G, section of flower showing calyx (c), lobed corolla (p), stamens inserted on corolla tube (s) and ovary (o) bearing at the summit a long style; H, pollen grains in different views; J, portion of stalk with fruits showing cylindrical calyx, the fruit really being enclosed within the calyx and in the nature of a pyxis. partly united they are spoken of as ' toothed," ' lobed," or ' parted," according to the degree of union. In the flowers of the Cruci ferae and Caryophyllaceae there is a conspicuous stalk to each of the separate petals, which is known as the UNGUIS or CLAW; while the upper outspreading portion is known as the LAMINA or blade. In the gamosepalous calyx and 25 386 A TEXT-BOOK OF BOTANY. the gamopetalous corolla the lower united portion is known as the TUBE, and the upper outspreading portion as the LIMB or " border." The form of the calyx and corolla is quite characteristic for a number of important families. In the Compositae there are two characteristic forms of corolla, namely, the tubular in the disk FIG. 226. Apocynum androsamifolium: A, portion of a flowering branch; B, a flower showing the short calyx tube and the corolla with more or less spreading lobes; C, longi- tudinal section of flower: c, calyx teeth; p, corolla lobes; a, anthers; and p, ovary; D, single stamen with long spurs (s). E, a flower of .4. cannabinum showing the corolla with ascending lobes. flowers and the ligulate in the ray flowers ; in the Papilionatse the corolla, from its fancied resemblance to a butterfly, is de- scribed as PAPILIONACEOUS (Fig. 221, B) ; in the Labiate the petals are united into two lip-like divisions, and the corolla is said to be BILABIATE (Fig. 223, F). There are two kinds of bilabiate MORPHOLOGY OF HIGHER PLANTS. 387 K FIG. 227. Flowers of the Compositae. Inula Helenium: A, ligulate floret; B, tubular floret; C, achene with pappus; D, pollen grains; E, united anthers showing hooked hairs (h) at the base. F, tubular floret of Safflower (Carthamus tinetorius). Dandelion (Taraxacum officinale): G, ligulate floret; H, one of the achenes showing spreading pappus on a long stalk which develops after fertilization. J, ligulate floret of Coltsfoot (Tussilago Farfara). Marigold (Calendula officinalis): K, ligulate floret; L, one of the double hairs from corolla, c, corolla; s, stamens; t, stigmas; p, pappus; h, hairs. 388 A TEXT-BOOK OF BOTANY. corollas — one, as in lavender, where the mouth of the tube is open, known as RIXGENT; and another, where the mouth is closed, as in Linaria, called PERSONATE. There are a number of other special forms of calyx and corolla, particularly the latter, and of these may be mentioned the follow- ing : A corolla, like that of the harebell, which is more or less bell- shaped, is termed CAMPANULATE; a more or less campanulate corolla contracted near the opening, as in Gaultheria, is spoken of as URCEOLATE or urn-shaped ; in the morning glory and other Convolvulacese the corolla is said to be INFUNDIBULIFORM or funnel-shaped ; a corolla in which the limb spreads abruptly from the tube, as in Phlox and coffee, is termed HYPOCRATERIFORM or salver-shaped ; a corolla with a short tube and outspreading limb, as in potato, is said to be ROTATE or wheel-shaped ; a rotate corolla with the margin more or less upturned is called CRATERI- FORM or saucer-shaped ; in aconite the upper petal is hood- or hel- met-shaped, and the corolla is spoken of as GALEATE ; in the violets one of the petals has a spurred appendage and the corolla is de- scribed as SACCATE or calcarate, while the modified petal in the orchids is known as the LABELLUM. DURATION OF CALYX AND COROLLA. — There is considerable difference in the length of time that the calyx and corolla persist, not only with reference to each other but in different plants. The parts are said to be CADUCOUS when they drop from the flower as soon as it opens, as the calyx of the poppy ; when they remain for a day or so, they are said to be EPHEMERAL or fugacious, as in the petals of the poppy ; in the rose and apple the petals fall away soon after the pollen reaches the stigma and they are said to be DECIDUOUS ; in some flowers the petals wither but persist until the maturing of the fruit, as in the Droseracea?, and are known as MARCESCENT ; the calyx may remain unaffected until the maturing of the fruit, as in the Labiatse, when it is said to be PERSISTENT. Bracts. — In addition to the floral envelopes, other more or less modified leaves are borne on the flower branch below the flower, frequently at the base of the flower stalk, and these have received the name BRACTS. The bracts closely resemble the foli- age leaves, but usually are smaller and frequently are mere scales, without chlorophyll. In some cases, however., they are large and MORPHOLOGY OF HIGHER PLANTS. 389 showy, looking like petals (petaloid), as in the water arum (Fig. 263), the common dogwood; Bougainvillea and Poinsettia seen in greenhouses. The Torus constitutes the terminal portion of the flower axis or stalk, and is usually more or less conical and somewhat enlarged. When the torus is of this shape the parts of the flower are inserted upon it in serial succession, all of the other parts arising below the pistil. It may, however, be modified into a hollow or cup-like structure which grows up around the ovary, carrying the other parts of the flower (sepals, petals, and stamens) with it, thus changing the relative position of the parts, although it should be understood that the ovary occupies practically the same .position in the two cases. When the torus is of the first type and the other parts of the flower are inserted below the ovary, the flower is said to be HYPO- GYNOUSJ as in the orange flower (Fig. 78, A] and the ovary superior ; but when the torus forms a cup-shaped receptacle and the other parts of the flower arise on its margin above the ovary, the flower is called EPIGYNOUS, as in the clove (Fig. 78, B ; 223 C) and the ovary inferior. In other cases a ring of leaf-like tissue arises from the torus, forming a cup-like receptacle or tube which is known as the perianth tube, the sepals, petals, and stamens bein^ inserted on its margin. The perianth tube may be free from the ovary, when the flower is said to be PERIGYNOUS and the ovary half inferior or half superior, as in cherry (Fig. 223, B] ; or in the case of an epigynous flower it may form a prolongation of the cup-shaped torus. Prefloration or estivation is the arrangement of the parts of the flower — more especially the calyx and corolla — in the bud. Some of the terms used in this connection are also employed in the study of vernation. The following are some of the terms which are employed : VALVATE, when the sepals or petals meet each other at the edges, as in Malvaceae ; IMBRICATED, when the sepals or petals overlap each other, as in the Magnoliacere ; PLICATE or PLAITED, when the divisions are united and folded together, as in the petals of Convolvulus and Datura. The sepals and petals do not necessarily possess the same arrangement, as in the Onagraceae, where the sepals are valvate 390 A TEXT-BOOK OF BOTANY. and the petals are convolute. Furthermore, in addition to the principal types of estivation and vernation already given, there are a number of special modifications of these, depending upon the number and arrangement as well as direction of the over- lapping parts of the flower- or leaf-bud. Coalescence and Adhesion. — Not only may the divisions of the same circle or whorl of the flower be united, but even those of different circles, and a number of terms are used to describe these modifications. When the divisions of the same circle are united there is said to be a COHESION or COALESCENCE of the parts. When the divi- sions of different circles are united, as of stamens with corolla, the union is spoken of as ADHESION or adnation, as in Convolvulus. Chorisis and Multiplication of Parts. — In contrast with the reduction in number of parts of the flower due to union, there may be an increase in the number of parts due to simple division or splitting of the parts, and this is known as chorisis or deduplica- tion. An illustration of this is furnished by the stamens of the orange flower, where from a single initial stamen or primordium a group of from 3 to n stamens may be produced. In other cases there may be a multiplication in the number t of parts from the beginning, each part arising independently on the torus, as in the stamens of rose. This, of course, would not be termed chorisis, as no splitting or branching takes place. Double Flowers. — In double flowers there is an increase in the number of petals, which is considered to be due to the methods of cultivation and the stimulus of an increased food- supply. This results in several ways : ( i ) By transformation of the sporophylls, more particularly the stamens, into petals; (2) by division or chorisis of the stamens or carpels with subsequent transformation into petals; (3) by division or branching of the petals; and (4) by the production of new series of petals. The extra petals in double carnations and double roses trace their origin to the stamens, while in Fuchsia they are the result of chorisis of the petals. In the snow-ball (Viburnum Opuhis) and hydrangea the essen- tial elements have undergone a complete transformation, and the flowers, while large and showy, are sterile. In the white water lily MORPHOLOGY OF HIGHER PLANTS. 391 (Nymphcca) there is a series of parts ranging from stamens with narrow filaments and stamens with broad petaloid filaments to petals tipped with a small anther and regular petals (Fig. 221, A). In this case the stamens are considered to result from the trans- formation of the petals. In the case of green roses and green strawberry flowers the petals become green and leaf-like, and the change is spoken of as CHLOROSIS or CHLORANTHY. In some flowers even the ovules are replaced by leaf -like processes or appendages, as in Drosera and clover. Arrested Development. — The arrest or suppression of parts of the plant, particularly of the flower, is of very common occur- rence. Just as there are millions of seeds that never find suitable conditions for germination, so in the flowers of a large number of plants a very large proportion of the ovules never develop into seeds, the plants in many instances not furnishing sufficient nutriment for all of the ovules to mature. Under Leaves it was stated that in the axil of each leaf there is a bud. This is not always apparent, but if the plant be subjected to some special stimulus, some of the latent buds will become evident. For example, the rubber plant (Ficus), so commonly cultivated as an ornamental plant, shows a. tendency to develop a straight, un- branched shoot, but if the tip of the shoot be cut off, the buds in the axils of the upper leaves will develop into branches, while some of those lower down will form small protuberances, but develop no further. In other cases there is a loss of parts which seems to be due to loss of function. When there is a partial loss of the element, as of the anthers in the flower of catalpa, it is said to be imperfectly developed or ABORTIVE. When the entire ele- ment remains undeveloped, as in some of the stamens of the Labi- atae, it is said to be SUPPRESSED (Fig. 223, F). In flax the stamens of the outer whorl are reduced to thread-like processes. Such sterile or aborted stamens are called STAMIXODES (staminodia). In other plants the parts are not apparently arrested, but have not yet been differentiated, as is the case in the Lily family, where the perianth is composed of segments which are more or less alike (Fig. 269). In other cases, however, there seems to be a suppres- sion or arrest of the floral envelopes. Cleistogamous Flowers. — In addition to the regular flowers 392 A TEXT-BOOK OF BOTANY. some plants produce cleistogamous or closed flowers. In these flowers the corolla is usually suppressed. The flowers develop stamens and pistils but remain closed, and thus there is no chance for cross-pollination. The cleistogamous flowers appear later than the regular flowers and are more or less inconspicuous, developing under the leaves and sometimes underground. Of the plants producing cleistogamous flowers, the following may be mentioned : various species of Viola, Polygala, etc. Classes of Flowers. — As we have seen, the megasporophylls and microsporophylls in the Gymnosperms are borne on separate branches, thus giving rise to two kinds of flowers or cones. While the separation of the stamens and pistils is exemplified in a number of plants in the Angiosperms, still it is not the rule, and these two elements are usually borne close together on the same axis, — i.e., they both enter into a single flower structure. Such a flower is said to be HERMAPHRODITE or bisexual, and most of the conspicuous flowers are of this kind, as roses, buttercups, lilies, etc. Inasmuch as the stamens and pistils constitute the essen- tial elements of the flower, hermaphrodite flowers are also spoken of as PERFECT, providing the stamens and pistils are capable of exercising their generative functions. When the stamens and pistils occur in separate flowers the flowers are said to be UNI- SEXUAL or IMPERFECT, as in willow, oak, hickory, etc. A flower having only a pistil or pistils is called PISTILLATE (Fig. 219, A ) , while one having only a stamen or stamens is STAMINATE, as in oaks. The staminate and pistillate flowers may be borne on the same plant, when it is said to be MONCECIOUS, as in castor bean, chestnut, hickory, alder ; or they may be borne on separate plants, when the plant is called DIOECIOUS, as in willows and poplars. Plants bearing hermaphrodite and unisexual flowers on the same individual plant or on different individuals are called POLYGAMOUS, as in Ailanthus. A COMPLETE flower is one which possesses both kinds of essen- tial elements and both kinds of floral envelopes, and is SYMMET- RICAL when a plane can be laid in all directions, the parts being alike, and when the number of parts in each circle is the same or when the number in one circle is a multiple of that in the others ; as a rule, the number of stamens is some multiple of one of the MORPHOLOGY OF HIGHER PLANTS. 393 other parts, as in geranium (Fig. 223), where we find five sepals, five petals, ten stamens, and five pistils. Flowers are also spoken of as REGULAR or IRREGULAR, accord- ing to whether all the parts of a circle are uniform in shape or not; the flowers of geranium are regular, while those of violets are irregular. Regular flowers are also spoken of as ACTINO- MORPHIC or RADIAL, and irregular flowers as ZYGOMORPHIC. The latter are also spoken of as DORSIVENTRAL. Dorsiventral flowers either arise as such, as in some of the Leguminosae (Fig. 231), or they may arise as radial flowers and become dorsiventral dur- ing the course of development, as in willow herb (Fig. 224). In some flowers the floral 'envelopes are wanting, and the flowers are said to be NAKED, as in the willows and grasses. ANTHOTAXY.--The study of the arrangement of flowers on the stem is known as anthotaxy. The flowering axis may bear only a single terminal flower, as in Tulipa ; or the flowers may occur singly in the axils of the leaves, as in Viola canadensis. When, on the other hand, the flowers are borne upon a branch shoot, the internodes of which are more or less condensed, and the leaves smaller and of a more simple structure than the foliaceous leaves, the whole shoot is known as an INFLORESCENCE, and the leaves are called BRACTS. The flower thus represents a single unbranched shoot, while the inflorescence represents a branched or ramified shoot. The so-called bracts, besides being generally smaller than the leaves proper, are mostly sessile ; they may, however, be green, or membranaceous, or they may exhibit a bright coloration, as in Monarda. The stalk of the individual flower is called a PEDICEL, and may be naked, or bear one or two small bracts, which are called FORE-LEAVES or PROPHYLLA. In the monocotyledons there is usually only one fore-leaf, which turns its back to the mother-axis and is frequently two-nerved and two-keeled. In the dicotyledons there are generally two fore-leaves, which are placed to the right and left of the flower, as in the violets. The position of the floral leaves (the sepals, the petals and those of the perianth) depends upon the arrangement of the fore-leaves, so that in most of the monocotyledons, where there 394 A TEXT-BOOK OF BOTANY. is one mediane prophyllon, the first leaf of the perianth is placed on the front, while the two succeeding leaves of the perianth occupy a position of 120° from this (Fig. 254). When, on the other hand, as in the dicotyledons with pentamerous flowers, two fore-leaves are developed, the first floral leaf (sepal) is situated obliquely above the last fore-leaf, usually on the frontal part of the flower; the second sepal is directly behind the first or diagonally opposite to it, the remaining three leaves (sepals) occurring in a spiral of two-fifths (Fig. 280). Several deviations from this type occur, as in Lobelia (Fig. 224), Polygala, etc. Two types of inflorescence are distinguished: (i) The IN- DEFINITE, in which the flowers open or develop in acropetalous or centripetal succession, and (2) the DEFINITE, in which the flo\vers open in basipetalous or centrifugal succession. The in- definite type of inflorescence is seldom terminated by an ex- panded flower, and two classes of this type are distinguished : (a) Those in which the flowers are pedicelled, as in the raceme (Fig. 267) and umbel (Fig. 344), and (b) in which the flowers are sessile, as in the spike (Fig. 230) and head (Fig. 228). The RACEME is a long inflorescence with pedicelled flowers, which are frequently subtended by bracts (Figs. 224, 225, and 293)- The CORYMB is a modified raceme in which the pedicels of the basal flowers are much longer than those of the apical, and thus the inflorescence looks like an umbel. In the milkweed the flowers have pedicels of the same length which arise from the apex of the shoot or peduncle, and this form of inflorescence is known as an UMBEL. In the Umbelliferae a flower cluster or umbellet takes the place of the individual flowers of the umbel, and is known as a COMPOUND UMBEL (Figs. 346-348). The SPIKE is also generally a long inflorescence, the flowers being sessile (Fig. 230, illus. 3), the secondary spikes in grasses being known as SPIKELETS. The SPADIX is a form of spike, which is readily distinguished by the fleshy stem, in which the flowers are frequently deeply imbedded, and which is frequently surrounded by a large bract, the so-called SPATIIE, as in Aris?ema. The CATKIN is a kind of spike with small, often imperfect flowers, which falls off as a whole, as in the staminate catkins of the oak. The catkins are mostly decompound, and in some species MORPHOLOGY OF HIGHER PLANTS. 395 of Populus the single flowers are pedicelled, and hence are actually racemose rather than spicate inflorescences. In the head and the umbel the main inflorescential axis is exceedingly short and the innermost flowers are often destitute of bracts, in contrast with the external, which are frequently provided with bracts that are of quite considerable size. Sterile bracts also occur in these two types, and are called involucral leaves, as in Cornus Honda, where they are white or pink. There is also a difference in sex of the outer and inner flowers. While the head occurs as typical inflorescence in the Compositse, it also exists in some of the Umbelliferae. The flowers of the Compositcu are borne on a common torus, known as the disk, which is subtended by one or more circles of bracts, these constituting an INVOLUCRE. The flowers are of two, kinds, and they receive different names because of their form and position. Those situated near the margin of the disk are known as RAY-FLOWERS, and because they possess more or less strap- shaped corollas are also known as LIGULATE FLOWERS. Those occupying the central portion of the disk are known as DISK- FLOWERS, or as TUBULAR FLOWERS because of the tubular shape of the corolla. Most of the Composite possess both ligulate and tubular flowers, as Arnica, Matricaria (Fig. 228), the common daisy, etc. But some of the members of the family have only ligulate flowers, as chicory and dandelion, and a relatively few have only tubular flowers. Two types of definite inflorescence are distinguished : ( I ) the DIBRACHIOUS (bifurcate) CYME in which the inflorescence represents a series of very regularly arranged lateral axes, one on each side of the terminal or median flower, as in the Caryo- phyllacese ; and (2) the MONOBRACHIOUS (simple) CYME, of which there are several modifications, but common to all of them is the development of only one lateral branch to each terminal flower. In the SCORPIOID cyme the lateral axes are arranged alternately to the right and left, while in the HELICOID cyme the lateral axes are all on the same side of the main axis, as in Hypericnm. The so-called flower cluster is a cymose inflorescence of either the definite or indefinite type in which the flowers are almost sessile or very short pedicelled, as in Chenopodium, Juncus, etc. Some- 396 A TEXT-BOOK OF BOTANY. times the inflorescence may be decompound or complex, as in several Composite, where the heads may be arranged in cymes or racemes ; or, as in the Graminese, where the spikelets, which D FIG. 228. Matricaria: A, longitudinal section of head showing torus (a), involucre (b), ray florets (c) and disk florets (d). B, head with the florets removed, showing the long conical torus and the involucre (H). C, tubular floret showing the ovary (f) with glandular hairs (D1) and the embryo (S), which develops after fertilization; style (g) and bifid stigma (N), the surface of which is covered with hairs; n, nectaries; b, corolla tube with narrow lobes (a); stamens showing filaments (st), united anthers (A) and apex of connective (sp). D, ligulate floret showing ovary (F), and bifid stigma (N); tube of corolla (R) and the upper ligulate portion (Z). — After Meyer. are spikes, may be arranged in panicles, i.e., branched racemes ; or finally, as in Cryptotaenia (Umbelliferae), where the umbels are arranged in cymes. MORPHOLOGY OF HIGHER PLANTS. 397 Pollination and Fertilization. — Fertilization represents the final stage in the work of the flower as a whole, and has already been defined as the union of the egg-cell and a male nucleus. Pollination may be considered to include the transferral of the pollen grains from the anther to stigma and their subsequent germination thereon, this latter process resulting in the produc- tion of the male nuclei. Pollination thus represents but one series of changes or processes which precede fertilization, for, while the pollen grain is going through the various stages in development which lead to the formation of the male nuclei, a series of com- plex changes are going on in the embryo-sac leading to the develop- ment of the egg-cell. Our special interest in pollination arises from the fact that the pollen grains are not retained in the pollen sacs and are dependent upon various agencies for transferral to the stigma. This is a matter of great biological significance, for it is claimed that many of the special characters of flowers have a direct relation to pollination. The various ways in which the anthers open for the discharge of the pollen when it is ripe have already been considered (Fig. 221), but it may be added that the manner in which this is done usually appears to have a relation to the manner in which the pollen is to be carried to the stigma. In order that pollination may be effected, the stigma must be ripe or mature, when it is said to be receptive. It then usually secretes a sticky, sugary liquid which causes the pollen grains to adhere to the stigmatic surface (Fig. 83), and which at the same time serves as a nutrient to them. Usually the pollen grains begin to germinate in a short time after reaching the stigma, which is made evident by the pro- trusion of the pollen tubes. The stigma seems also to have the power of selection, for in many cases the pollen does not germi- nate as readily on the stigma of the same flower as on that of another flower, provided it be of the same or a nearly related species. When a flower possesses both stamens and pistils, — that is, is bisexual or hermaphrodite, — and its pollen germinates upon its own stigma, the process is known as close or SELF-POLLINATION, and if fertilization follows, this is known as SELF-FERTILIZATION. 398 A TEXT-BOOK OF BOTANY. While most hermaphrodite flowers are self -pollinated, there are some that are not, and this is brought about in several ways : ( i ) As already pointed out, the pollen may germinate better on the stigma of another flower than on the stigma of the same flower. (2) The anthers and pistils of the same flower may mature at different times, and this is one of the commonest ways of preventing self-pollination. Usually in such cases the stamens mature first. The common plantain (Plantago} furnishes an example of the maturing of the stigma before the anther. The flowers of this plant are arranged in spikes (Fig. 230, illus. 3 and 4) which belong to the indefinite class, and hence the lower flowers on the spike expand first. As stated, the pistil of each, flower matures first, and after it withers the stamens protrude and discharge their pollen. It is evident that the flowers can not be self-pollinated, nor is it likely that one flower will be pollinated by another of the same spike. (3) The stamens and pistils of the same flower may vary in length, as in Polygonum (Fig. 230, illus. I and 2) and Lythrum (Fig. 230, illus. 5), or stand in such other relation to each other that self-pollination will not be effected, as in some of the irregular or zygomorphic flowers, like those of Orchids. In these several cases the pollen grains either fall upon or are carried by various agents to the stigmas of other flowers, and this is known as CROSS-POLLINATION, and the fertilization which follows as CROSS-FERTILIZATION. Cross-fertilization is an advantage to the species, for usually the seeds which result from this process give rise to plants which are more vigorous and otherwise superior to those which result from self-fertilization. In some cases, in order to insure the pro- duction of fruit, hand-pollination is practised, as by the growers of vanilla and some other tropical plants of economic importance. In the case of unisexual flowers, or those in which the stamens and pistils are in separate flowers, there is, of course, no chance for self-pollination. Here, as in the case of cross-pollinated her- maphrodite flowers, pollination may be more or less close or it may be remote, as between flowers of the same cluster or inflores- cence, between flowers of different clusters or inflorescences on the same plant, or between flowers on different plants. In buckwheat (Fig. 230, illus. i and 2) and partridge berry MORPHOLOGY OF HIGHER PLANTS. 399 (Mitchclla rcpens) two kinds of flowers are produced, viz.: (a) one with short styles and long filaments, and another (b) with long styles and short filaments, and thus the flowers appear to be especially adapted for insect cross-pollination and are called DIMORPHIC. In still other cases one species gives rise to three kinds of flowers, depending upon the difference in the relative lengths of the styles and filaments, as in the purple loosestrife (Lythrum calcaratum) , and such flowers are called TRIMORPHIC. The external agents which are instrumental in carrying pollen from one flower to another and thereby promoting cross-pollina- FIG. 229. Visitation of flowers by insects showing how they gather the pollen and assist in cross-pollination, the one on the left being Lilium Martagon visited by a hawk moth, showing that while the proboscis is removing honey from the nectary the under side of the body is becoming covered with pollen; at the right Cydonia vulgaris, the common quince, visited by a bee, whose legs are becoming covered with pollen. — After Dodel-Port. tion are the wind, water currents, insects, small animals and birds, such as humming-birds, which are, even in temperate regions, to be observed visiting the garden nasturtium. In many of the early-flowering trees, as well as pines, Indian corn, etc., the flowers are devoid of showy, attractive features, but produce large quantities of pollen which is more or less dry and powdery and carried by the wind to other flowers. Flowers which are wind-pollinated are classed as ANEMOPHILOUS, and it is estimated that about one-tenth of all the flower-producing plants belong to this class. Plants which are pollinated by the aid of water currents are 400 A TEXT-BOOK OF BOTANY. FIG. 230. Manner of cross-pollination in some hermaphrodite flowers, i, 2. Flowers of buckwheat, showing long style and short filaments in i, and short styles and long filaments in 2: a, anthers; st, stigmas; n, nectaries. 3, Spike of plantain showing maturing of stamens below and pistils above. 4, Dissected flower of plantain: b, bract; c, calyx; p, corolla tube; s, stamens; t, protruding withered style. 5, Flowers of Purple willow-herb (Lythrum Salicaria), one side of the perianth removed from each. A is long- styled, B. medium-styled, and C, short-styled. The direction of the arrows and dotted lines indicates the best methods of crossing. — i, 2, 5, adapted from Warming. MORPHOLOGY OF HIGHER PLANTS. 401 •I-3 \ FIG. 231. A, flowering and fruiting plant of peanut (Arachis hypogaa) . After fertiliza- tion the carpophore (or stalk between calyx and ovary) grows in length, sometimes 4 to 8 cm., and curves downward penetrating the soil (el), after which the fruit develops. B. longitudinal section through the papilionaceous (bilateral) flower; C. longitudinal section through the pod Cpeanut). — After Taubert. known as HYDROPHILOUS, and under this head are included those plants which live under the water and those that produce flowers at or near the surface of the water. Those plants which depend upon the visitation of insects for 26 402 A TEXT-BOOK OF BOTANY. the transferral of the pollen in cross-pollination are called ENTO- MOPHILOUS (Fig. 229). They frequently possess bright, highly colored flowers, and it is considered that these serve as an attrac- tion to the insects which visit them. The insects are, however, probably more attracted by the odor and food products which they obtain, such as the nectar. The nectar is secreted by glands known as nectaries, which are variously located ; frequently they are on the torus, either between the ovary and stamens (Fig. 78) or between the stamens and petals. Sometimes the stamen is modified to a nectar-secreting spur, as in the violets. In aconite the nectary is developed from one of the posterior petals (Fig. 223, E). In seeking the nectar the pollen of the ripe anther may fall upon or adhere to the insects and thus be carried from one flower to another (Fig. 230). HONEY is a product formed through transformation of the plant nectar by honey bees. The nectar is supposed to be acted upon by certain salivary secretions of the bee and changed into a fruit-sugar, the so-called honey, consisting of a mixture of dex- trose and levulose. The nectar of buckwheat and clover (partic- ularly white clover) is the principal source of the commercial article. The nectar of some plants is poisonous and may furnish a poisonous honey (see discussion under Ericaceae). THE INNER STRUCTURE OF THE FLOWER. The inner structure of the flower bears a close resemblance to that of the stem and leaf. The BRACTS in almost all particulars are like the foliage leaf of the same plant, and the FLOWER STALK closely resembles the foliage stem. The CALYX, while resembling the foliage leaf, usually contains calcium oxalate in greater amount, and the chlorenchyma consists wholly of rather loose chlorophyll parenchyma ; the outer or under epidermis contains the stomata, and if hairs are present, they also arise from this surface ; the fibrovascular bundles are generally simple in structure, although in some cases, as in lavender, sclerenchymatous fibers are strongly developed. In the COROLLA the epidermal cells are generally more or less centrifugally developed, forming prominent papillae (Fig. 232, . /, B), which give the petals a velvety or satiny appearance, as in MORPHOLOGY OF HIGHER PLAXTS. 403 the rose ; glandular and non-glandular hairs are also developed which are peculiar to the corollas of irregular flowers, as in La- vanditla vcra and Viola tricolor (Figs. 124, 149-155, 232) ; stomata are comparatively few in number. The epidermal cells C M FIG. 232. Inner morphology of the flower as illustrated in Viola tricolor. A, epider- mal cells from the outer surface of the spurred petal showing papillae; B, epidermal cells from. the under surface of the petals, some of the cells showing centripetal thickenings, the two without thickenings indicating the epidermal mucilage-cells; C, epidermal cells from the under surface of the petals showing a zigzag outline and short centripetal thickenings; D, surface view of the mesophyll of the petals; E, corkscrew-like hair from the inner sur- face of the spurred corolla near the throat; F, a hair from the edge of an anther; G, epider- mal cells of the anthers; H, surface view of the mesophyll cells from the spurred stamen showing collenchymatous thickening; I, surface view of cells of endothecium; K, pollen grain viewed from the side; L, pollen grain examined in water; M, pollen grain observed in chloral solution. are but slightly cutinized, and in surface view are strongly undu- late and appear striate owing to the papillose development (Figs. 232 and 235). The chlorenchyma is made up of rather loose, branching parenchyma cells (Fig. 232, D), with large, intercellular spaces. The cells are free from chloroplastids, may contain 404 A TEXT-BOOK OF BOTANY. chromoplastids, or, like the epidermal cells, a colored sap ; in some instances, as in the buttercups, starch grains are also found in the mesophyll. Calcium oxalate crystals are usually present, and milk vessels are sometimes found, as in the Papaveraceae. The FILAMENT and connective possess a central nbrovascular bundle, around which are arranged comparatively small paren- chyma cells and among which secretion cells are sometimes scat- tered, as in Tilia. The pollen sacs consist of but two layers of cells — an outer layer called the "exothecium," which resembles the epidermis of the corolla, and an inner layer called the " endo- thecium," the cells of which are contractile and peculiarly thick- ened, this feature being rather characteristic for certain species (Fig. 232, 7). Lining the pollen sacs during their development, c FIG. 233. Several forms of pollen grains: A, crocus; B, arnica, with three thin places in the wall through one of which the pollen tube may protrude; C, lavender showing six thin places in the wall. there is a layer of cells, called the " tapetal cells " ; but these are usually sooner or later absorbed. The POLLEN GRAINS vary greatly in number, as well as in size and shape. They are usually more or less ellipsoidal, but may be spherical, as in Crocus (Fig. 233, A) ; more or less three- sided, as in the Composite and in cloves ; four- or five-sided, as in Viola tricolor (Fig. 232, K, L, M), and in some cases, as in the Pinaceae, they may be winged. In addition to protoplasm and one or more nuclei, pollen grains contain considerable oil and starch. The outer or enclosing membrane (Fig. 233) consists of two parts : an inner one, known as the " intine," and consisting of cellulose, and an outer, known as the * exine," apparently con- sisting chiefly of cutin ; in some cases the exine also contains an oil which is colorless, as in Salvia, or yellowish, as in lavender, and in some instances it may contain a viscid substance, causing MORPHOLOGY OF HIGHER PLANTS. 405 the pollen grains to adhere, as in (Enothera. The grains may be smooth or variously sculptured ; in most instances the exine is unevenly developed, leaving thin places through which the pollen tubes protrude in germination ; these give the appearance of c. FIG. 234. A, Crocus (Spanish saffron) showing two spherical pollen grains, a fragment of stigma with papillae, and fragment of an anther; B, Calendula showing 3 spinose pollen grains and fragment of corolla, the cells of which contain oil-like globules; C, Carthamus (so-called American saffron) showing 2 slightly spinose pollen grains and a fragment of the corolla with brown laticiferous vessels and numerous unicellular hairs. — After Weakley. grooves when the grains are dry, and the number of grooves is characteristic for different species ; in most of the Composite they are three in number ; in the Labiatse there are six, while in Crocus they are wanting (Fig. 234). The epidermal cells of the STIGMA are quite characteristic. 4o6 A TEXT-BOOK OF BOTANY. The cells of the epidermis, or so-called " stigma-epithel," may be palisade-like, forming a more or less wart-like mass, as in the viscous stigmas of the Umbellifene, or the outer walls may be modified to rather broad papillae, as in matricaria and arnica, or they may be developed into hair-like processes, as in crocus. The pollen tubes either enter the style through an open canal, as in the violets, or they penetrate into the conducting tissues of the style, either through the papillae, as in malva, or through the middle lamella of two neighboring papillae, as in Atropa Belladonna. The important tissue of the STYLE is the conducting tissue ; in styles which are hollow it forms the lining of the canal, the cells resembling those of the stigma-epithel ; in styles that are solid the conducting tissue occupies the central axis and consists of somewhat elongated cells, the walls of which are generally thick, frequently strongly refractive and possess the property of swell- ing, being furthermore separated by large intercellular spaces. Surrounding the conducting tissue are thin-walled parenchyma cells, in which the fibrovascular bundles are distributed, the num- ber of groups of the latter corresponding to the number of carpels that compose the gynsecium. There may also occur secretion cells, containing mucilage, as in malva, or oil and resin, as in matri- caria. Occasionally, the parenchyma is replaced either in part or entirely by mechanical cells, and the epidermal cells may be modified to hairs. The tissues of the OVARY are, as a rule, in a very rudimentary condition ; in fact, so rudimentary that it is difficult to distinguish the ovaries of two flowers that develop into quite different fruits. In some instances it is said that, notwithstanding the subsequent changes, each cell of the fruit is already indicated in the ovary. The ovary possesses an outer and an inner epidermis ; the outer is provided with stomata and may also possess hairs ; the inner may also have stomata and after fertilization may develop secre- tion hairs, as in the orange. Between the epidermal layers occur thin-walled parenchyma cells which contain leucoplastids and chloroplastids, and in which the fibrovascular bundles are dis- tributed, these being usually simple, or complex, as in the pea. The number of fibrovascular bundles is more or less dependent MORPHOLOGY OF HIGHER PLANTS. 407 FIG. 235. Inner morphology of flower of Primula officinalis: A. papilla? on stigma of flower with long styles; B, papillae from stigma of flower with short styles; C, sec- tion through petals showing papillose epidermal layers and branching cells of mesophyll ; D, section through corolla tube showing glandular hairs on epidermis; E, surface view of epidermal cells of petals, those of the corolla tube being elongated and shown on the left, while those of the outspreading petals are polygonal and striated from the folds in the papillae; F, a pollen grain. — Redrawn by Haase from drawing of Hans Kramer in Ber. d. d. pharm. Ges., 1907, p. 352. 408 A TEXT-BOOK OF BOTANY. upon the number of carpels that make up the gynsecium ; as a rule, there is a strong fibrovascular bundle which corresponds to the mid-vein of each carpel. The PLACENTA is a development from the inner epidermis. It is traversed by a fibrovascular bundle from which branches are given off to the individual ovules ; it may have a conducting tissue similar to that found in the style, and in some cases the epidermis of the stalk of the ovule may be developed to a stigma-epithel. The OVULE not only possesses a distinct form as already given, but the internal structure, by reason of the changes associated with fertilization, is more or less characteristic for certain species and genera. It has an epidermal layer, the outer walls of which are more or less cutinized, and it consists for the most part of paren- chyma cells rich in protoplasm and food-materials ; in addition the embryo-sac contains a number of nuclei. The stalk and raphe are connected with the placenta by means of a fibrovascular bundle. The NECTAR may be secreted by certain of the epidermal cells of various parts of the flower ; these may resemble the ordinary epidermal cells or they may be modified to papillae, as in the spurred stamens of the violets, or to hair-like processes, as in malva. The cells which secrete nectar constitute the ' nectar- apparatus," and the walls are usually thin and more or less cutin- ized. The nectar-apparatus is found more generally upon some part of the stamen, but the sepals and petals are not infrequently saccate or spurred, which adapts them for holding the nectar. V. OUTER MORPHOLOGY OF THE FRUIT. After the fertilization of the ovule or ovules, the parts of the flower that play no further part either in protecting the seed or aiding in its dispersal soon wither and are cast off ; in most flowers the petals lose their color and, together with the stamens, style, and stigma, wither and fall away shortly after fertilization. The stigma may, however, persist, as in the poppy ; the style may like- wise remain, as in Ranunculus, or even continue to grow or lengthen, as in Taraxacum; in other cases the calyx persists, as in orange and belladonna ; in still other cases the torus may be- come fleshy and form a part of the fruit, as in pimenta and apple. The fruit may consist, therefore, not only of the ripened pistil, MORPHOLOGY OF HIGHER PLANTS. 409 FIG. 236. Different types of fruits. A, silique of mustard showing the separation of the two valves leaving the seeds attached to the central axis; B, spinous capsule of Stra- monium showing septifragal dehiscence into four valves, the capsule being strictly 2- locular but apparently 4-locular owing to the formation of false dissepiments; C, s-valved capsule of Geranium in which the carpels become detached from one another and roll up- wards remaining attached to the beak-like compound style; D, capsule of Hyoscyamus showing transverse dehiscence by means of a lid (i) and the two loculi containing numerous small seeds; E, fruit of strawberry showing fleshy torus and numerous embedded akenes; F, silicula of shepherd's-purse showing seeds attached to central axis and longitudinal dehiscence of the valves which remain attached below; G, fruit of rose, so-called rose "hip," the akenes being enclosed by the hollow oval torus which shows remains of calyx at the apex; H, multiple fmit of mulberry composed of small drupes, the pulpy portion of each consisting of the fleshy perianth. — Adapted from Warming. but also of other parts of the flower and torus which persist or develop with it. A TEXT-BOOK OF BOTANY. The wall of the fruit is called the PERICARP, and, like the leaf, it consists of three distinct layers, viz. : ( I ) the outer layer corre- sponding to the outer epidermis of the ovary is called the EPICARP or EXOCARP ; (2) the inner layer corresponding to the inner epidermis of the ovary is called the ENDOCARP, or, from the fact that it is sometimes hard and stone-like, it is called the PUTAMEN, as in the prune; and (3) the middle layer situated between the epicarp and endocarp is called the MESOCARP ; and from the fact that it is sometimes succulent or fleshy, as in the prune, it is also called the SARCOCARP. There are a number of distinctive and descriptive names applied to fruits. Some of the more imoortant are as follows: FIG. 237. A, transverse section of colocynth showing seeds (s) borne on parietal placentas; B, transverse section of fruit of Ricinus communis showing septicidal dehis- cence of capsule, the seeds (s) being borne on axial placentas; C, transverse section of card- amom showing loculicidal dehiscence, the seeds (s), as in B, being borne on axial placentas. An Achene is a non-fleshy, or so-called dry, unilocular and one-seeded, indehiscent fruit, in which the pericarp is more or less firm, and may or may not be united with the seed. Achenes may be inferior, as in the Composite (Fig. 227), where they develop from inferior ovaries, being frequently surmounted by the pappus or calyx; or half inferior, as in the rose (Fig. 236, G), where they develop from half inferior ovaries ; or superior, as in the buttercup (Fig. 223, £>). A Berry is a fleshy, indehiscent fruit, the seeds of which are embedded in the sarcocarp ; berries are superior when they develop free from the torus, as in belladonna (Fig. 239), capsi- cum, grape, etc., and inferior when the torus forms a part of the fruit, as in banana, cranberry (Fig. 244), and gooseberry »g- 245)- MORPHOLOGY OF HIGHER PLAXTS. 411 A Capsule is a dry, dehiscent fruit, consisting of two or more united carpels. Dehiscence in capsules may occur in five different ways: In the castor-bean (Fig. 237, B] the carpels separate from each other along the walls or septa (dissepiments) , the seeds being discharged along the ventral suture of the separated carpels, and this mode of dehiscence is called SEPTICIDAL. In mustard (Fig. FIG. 238. Capsules of poppy (Papaver somniferum), whole and in transverse and longitudinal sections, showing dissepiments and remains of radiate stigmas at the apex, which are porous and through which the seeds are discharged, i, French capsules; 2, German capsules. 236, A) the dissepiments remain intact and dehiscence occurs along the margin of the capsule, and is therefore called MARGINICIDAL ; but as the partial carpels (or valves, as they are termed) separate from the walls or septa, the dehiscence is also known as SEPTI- FRAGAL. In cardamom ( Fig. 237, C;) the septa as well as valves are united, and at maturity the latter separate and dehisce at points in the margin corresponding to the mid-vein of the carpel, and 412 A TEXT-BOOK OF BOTANY. this form of dehiscence is known as LOCULTCTDAL. In poppy capsules (Fig. 238) there are a few openings beneath the united FIG. 230. Several forms of fruits: A, branch of Afocynum androscemifolium showing numerous flowers and a single fruit with 2 long, slender follicles. Comparative size of follicles in A. androscemifolium (B), and A. cannabinum (C). Branch of Solatium carolinense showing a number of small superior berries (D). Pyxis of Scopolia carniolica showing slightly lobed calyx and upper portion of fruit (E). Pyxis in Hyoscyamiis niger showing calyx lobes extending much above the fruit (F). Berry of Atropa Belladonna cut trans- versely and showing the numerous small seeds (G). Young spinose eapsule of Datura Stramonium (H). stigmas through which the seeds are expelled, and this form of dehiscence is known as POROUS. In hyoscyamus (Fig. 236, D) a MORPHOLOGY OF HIGHER PLANTS. portion of the capsule comes off from the remainder like a lid, and this form of dehiscence being circular or transverse to the 1st qst K — Alb- ste m FIG. 240. The fruit of the cocoanut palm (Cocos nuciferd): I, ripe cocoanut fruit showing lower part of axis forming the stem (S), upper end of axil with scars of male flowers (A), epicarp (Ep), mesocarp (M) with fibers, endocarp or hard shell (E), portion of testa adhering to endosperm (T), endosperm surrounding cavity of nut (Alb) and germinating eye (K); II, longitudinal-radial section of endocarp through the stone cells and edge of bundle showing transversely elongated and isodiametric stone cells (qst), longitudinally elongated stone cells (ist), thick-walled porous cells (f), pitted tracheae (g) and spiral tracheae (sp) ; III, longitudinal section of a large (mesocarp) fiber showing stegmata (ste), silicious body (Si), bast fibers (f), tracheids with small pits (t), tracheids with large pits (t'), spiral tracheae (sp), reticulated tracheae (r), scalariform tracheae (sc), sieve tube (s) and cambiform cells (c and c')- — After Winton. sutures of the carpel, it is called CIRCUMCISSILE. A capsule of this kind is known as a Pyxis or Pyxidium. A TEXT-BOOK OF BOTANY II VI If E End FIG. 241. Fruit of the huckleberry (Gaylussacia resinosa): I, fruit seen from above; II, transverse section of fruit; III, stone; IV, transverse section of stone showing endocarp (End), testa (S), endosperm (E) and embryo (em); V, transverse section of outer portion of the pericarp showing c-picarp (epi), hypoderm (hy), mesocarp (mes) and stone cells (st) ; VI, transverse section of endocarp and seed showing large isodiametric stone cells (End), narrow longitudinally extended fibers (If), testa (S), hyaline layer or nucellus vN) and endosperm (E). — After Winton. MORPHOLOGY OF HIGHER PLANTS. 415 FlG. 242. Cultivated strawberry (Fragaria chilo'ensis}: I, Compound fruit showing fleshy receptacle bearing the achenes in deep depressions; II, isolated achene; III, achene showing style (Sty), stigma (Sti) and connecting bundle (B); IV, achene in transverse section, pericarp (F), testa (S),raphe (R), endosperm (E) and embryo (Em); V, receptacle in surface view showing epidermis (Ep), with hair (h), and stoma (sto) ; hypoderm (hy) and sphero-crystals (k) ; VI, achene in transverse section showing pericarp (F) consisting of epicarp (epi), mesocarp (mes), spiral vessels (sp), crystal layer (k), outer endocarp (If) with longitudinally extended fibers and inner endocarp (qf) with transversely extended fibers; testa (S) consisting of epidermis (ep) with reticulated cells, elongated brown cells (br), hyaline layer or nucellus (N) and endosperm (E) consisting of a single layer of aleurone grains; VII, style and stigma. — After Winton. 416 A TEXT-BOOK OF BOTANY. II If--—! >End' icr — k- FIG. 243. Red Raspberry (Rubus Idceus): I, Compound fruit consisting of a number of drupelets crowded together on the top and sides of the receptacle; II, transverse section of a drupelet showing^epicarp (epi), hypoderm (Hy), mesocarp (Mes), outer endocarp (F), inner endocarp (F'), testa (S), raphe (R), endosperm (E), and embryo (Em); III, stone including endocarp and seed; IV, stone somewhat magnified; V, style and stigma; VI, surface section of epicarp showing straight hair (h')( sinuous hairs (h) and stoma (sto) ; VII, transverse section of endocarp and seed showing endocarp (End) consisting of longi- tudinally extended fibers (If), transversely extended fibers (qf), testa (S) consis'ting of epidermis (ep), parenchyma or nutritive layer (p), and inner epidermis (iep) ; hyaline layer or nucellus (N), endosperm (E) with aleurone grains (k). — After Winton. MORPHOLOGY OF HIGHER PLANTS. A Caryopsis, or Grain, is an indehiscent, non-fleshy fruit possessing a thin pericarp, which is closely adherent to the thin seed-coats, as in wheat, corn, and other Graminere (Figs. 255, 256). V E VII FIG. 244. The fruit of the cultivated cranberry (Vaccinium macrocarpon): I, berry seen from above; II, transverse section of berry; III, single seed; IV, transverse section of seed showing outer epidermis (S), inner layer of seed-coat (S'), raphe (R), endosperm (E) and embryo (Em); V, surface section of endocarp with stoma; VI, seed in transverse sec- tion showing epidermis of seed-coat (ep) with sclerenchymatized and mucilaginous layers, inner layer of seed-coat (m) and endosperm (E); VII, surface section of epidermis of seed- coat. — After Winton. A Cremocarp is a dry, indehiscent fruit which consists of two inferior achenes, known as MERICARPS ; these are separated from each other by means of a stalk known as a CARPOPHORE. 27 4i8 A TEXT-BOOK OF BOTANY FIG. 245. The fruit of the American Gooseberry (Ribes oxyacanthoides): I, whole fruit; II, transverse section of fruit with seeds; III, seeds deprived of gelatinous coat; IV, floral parts; V, surface section of epidermis from margin of calyx with hairs; VI, surface section of epidermis from throat of calyx with hair. — After Winton. This fruit is characteristic of the Uuibcllifcrcc. (Consult Volume II for pharmacognosy of medicinal umbelliferous fruits.) A Drupe is a fleshy, indehiscent fruit with a more of less succulent and well-developed sarcocarp and an indurated endo- MORPHOLOGY OF HIGHER PLANTS. 419 carp. Drupes are superior when they are free from the torus, as in prune ; inferior when the torus forms a part of the fruit, as in pimenta. Drupes are also spoken of as " dry " when the sarco- carp is less succulent, as in Rhus glabra, or when they are col- lected unripe, as in pepper, pimenta, and cubeb. The fruits of the raspberry and blackberry consist of a collection of little drupes, the whole being known as an ET.ERIO. In the blackberry the drupelets cohere with the fleshy torus, while in the raspberry the drupelets cohere with one another, forming a cap which is sepa- rable from the cone-shaped torus. If the drupelets of the rasp- berry are examined closely it will be found (Fig. 243) that each has from 4 to 7 facets on the sides formed by the pressure of the adjoining drupelets. These facets are usually slightly convex or concave. Tschierske states that the individuals cling together, first, because of the closely-fitting adjoining facets, the slightly convex surface of one fitting into a corresponding concave surface of another; and, second, because of the interlocking of the sinuous hairs. A Follicle is a dry, dehiscent fruit which consists of one or more separate carpels, the dehiscence being usually along the ventral suture (Fig. 239) ; in Delphinium the carpels are single ; in aconite from 3 to 5, and in star-anise (Illicium) from 7 to 8 ; in magnolia the carpels are numerous, forming a kind of succulent cone, and dehisce along the dorsal suture. A Galbalus is a berry-like fruit, formed by the coalescence of fleshy, open scales, as in juniper (Fig. 75). Hesperidium.- -The fleshy, indehiscent, superior fruit of citrus, as lemon and orange, is known as a hesperidium. The pericarp is more or less coriaceous, and from the inner walls secretion hairs develop, which contain sugar and an acid cell-sap, these consti- tuting the fleshy portion in which the seeds are embedded. A Legume is an elongated, monocarpellary, usually dry, dehiscent fruit, in which dehiscence takes place along both sutures, the carpel thus dividing into two halves, or valves, as in the garden pea (Pisum) and other members of the Leguminosse (Fig. 231). In some cases legumes are jointed or articulated and indehiscent, breaking up at maturity into a number of parts which are dis- persed in much the same manner as samara-fruits, as in Meibomia. 420 A TEXT-BOOK OF BOTANY. Legumes may be not only indehiscent but fleshy, as in Cassia fistula. A Nut is an achene-like fruit, the pericarp of which is more or less indurated. Nuts are sometimes subtended (as in acorns) or enclosed (as in chestnuts) by a kind of involucre, forming what is technically known as a cupule ; and a fruit consisting of a nut and cupule is known as a GLANS. The achene-like fruit of the Labiate is spoken of as a Nutlet. A Pepo is an inferior berry, in which the placentas have become developed into succulent layers, as in the watermelon, cucumber, and colocynth. A Pod is a general term used to designate all dry, dehiscent, apocarpous, or syncarpous fruits, as capsules, follicles, and legumes. A Pome is an indehiscent, half-inferior, fleshy, syncarpous fruit, as in the apple. The carpels constitute the core, and the fleshy part is developed from the torus. A Samara is a winged, achene-like fruit. The winged ap- pendage may be at the apex, as in white ash, or around the edge, as in elm. Two samaras may be united into one fruit, which is called a " double samara," as in maple. A Silique is a narrow, elongated, 2-valved capsule which is separated by the formation of a false dissepiment into 2 locules, as in the Cruciferse (Fig. 236, A). A Sorosis is a fleshy fruit resulting from the aggregation of the carpels of several flowers, as in mulberry (Fig. 236, H) and pineapple. A Strobile or cone is a scaly fruit, at the base of each scale of which there is either a seed, as in the Pinacetc, or an achene-like body, as in hop. A Syconium consists of a succulent hollow torus, which en- closes a number of achene-like bodies, as in the fig (Ficus). An Utricle is an inferior achene with a thin and loose pericarp, as in Chcnopodhun. Classification of Fruits. — More or less artificial classifications of fruits have been made. They may be grouped either according to structure or according to their manner of protection or dispersal, the following classification being based on the structure : MORPHOLOGY OF HIGHER PLANTS. 421 From a number of flowers. Dry .4. With a compound pistil. From a single flower a. Indehiscent Fleshy . b. Dehiscent. , . . . \ Dry . . Strobile or Cone Sorosis Syconium Achene Caryopsis Cremocarp Nut Samara Utricle Berry Drupe Etaerio Hesperidium Pepo Pome [Capsule [Follicle B. With a simple pistil. a. Indehiscent . \ Fleshy . . I Drupe b. Dehiscent \ Dry. [Follicle I Legume THE INNER STRUCTURE OF FRUITS. The inner structure of fruits is quite variable and it is difficult to treat of this in a general way. In the simplest fruits there are three distinct layers, as in the capsule of cardamom, in which there is an outer epidermis of isodiametric or polygonal cells, an inner epidermis of more or less obliterated and elongated cells, between which is a thin-walled parenchyma traversed by a number of fibrovascular bundles. In some cases the other epidermis contains numerous stomata, as in poppy capsules, or is developed into hairs and other out- growths or appendages, as in anise, arnica, sumach (Fig. 148), and raspberry (Fig. 243). The inner epidermis may also contain stomata, as in the poppy, or be developed into hairs, as in vanilla and orange, or more or less obliterated, as in achene-like fruits, or modified to sclerenchy- matous elements, as in drupes. 422 A TEXT-BOOK OF BOTANY. The middle layer, which is composed of parenchyma, may con- tain protoplasm, starch, sugars, calcium oxalate, coloring princi- ples, alkaloids and other principles, and it may also have oil-secre- tion cells, as in cubeb and pepper, or oil-secretion canals, as in ^orange (Fig. 121) and the fruits of the Umbelliferae, in the latter FIG. 246. Rhamnus cathartica. A, cross-section through wall of the pericarp. E, epi- carp; F, sarcocarp; H, endocarp; e, epidermis; o, calcium oxalate in cells of hypodermis; p. parenchyma; h, secretion cells containing a substance which is insoluble in alcohol or chloral solutions, soluble in solutions of potassium hydroxide, and colored reddish brown or green- ish with ferric chloride solutions; c, calcium oxalate cells of endocarp; w, sclerotic cells; f, stereome cells. B, cross-section of entire fruit, showing one seed; E, F. H, g, f, w, as in A; S, seed-coat; S1, outer wall of seed-coat; End, endosperm; c, cotyledons; g, vascular bundle. C, cross-section of a seed: S1, S2, S3, different layers of the seed-coat; R, vascular bundle of raphe; t, position of vessels of mestome strand; g, mestome strand; Rf, cleft in which raphe is situated; End, endosperm; C cotyledons; Sv, cells with thick walls ;Sp,parenchymatous cells. — After Meyer. of which they are known as vittae (see Volume IT) ; milk vessels sometimes occur, as in poppy ; a collenchymatous layer is some- times developed beneath the epidermis, as in capsicum ; in some cases sclerenchymatous cells may be present, as in pimenta and cubeb (Fig. 135) ; and in still other instances the entire pericarp may be made up of stone cells, as in the nuts. MORPHOLOGY OF HIGHER PLANTS. VI. THE OUTER MORPHOLOGY OF THE SEED. 423 The seed may be defined as the fertilized and developed ovule. The seeds of different fruits vary in number as well as in size FIG. 247. Transverse (I) and longitudinal (II) sections of oat grain (Arena satfva): i, 2, cells of pericarp; 3, seed-coat; 4, remains of perisperm; 5, cells containing gluten; 7, endosperm cells containing considerable proteins and some starch; 6, endosperm cells With polygonal compound starch grains; 8. fibrovascular bundle of the pericarp. — After Harz. and shape. In form they correspond to the ovules ; in size they vary from about 0.600 mm., as in lobelia, belladonna, etc., to 10 or 15 centimeters in diameter, as in the cocoanut palm. Seldom are 424 A TEXT-BOOK OF BOTANY. all of the ovules of the pistil fertilized, hence the number of seeds is usually less than the number of ovules. Structure of Seed. — After the fertilization of the egg-cell certain changes take place in the embryo-sac : At one end the developing embryo is attached to the wall by a short stalk or suspensor (Fig. 82) ; the nuclei, lying in a mass of cytoplasm FIG. 248. Citrullus Colocynthis. A, seed: a, in longitudinal section, and b, surface view; S.deep clefts or fissures; m, micropyle; g, hilum; w, radicle; c, cotyledons. B, parenchyma cells of ripe fruit showing simple pores, the walls are colored blue with chlor-zinc-iodide. C, longitudinal section of wall of pericarp of ripe fruit showing e, epidermis; p, parenchyma; Sc, sclerotic cells which gradually pass into a thick-walled parenchyma consisting of small cells (p'); g, spiral vessels; P, isodiametric, porous parenchyma cells, containing air and of which the fruit for the most part consists. D, cross-section of seed-coat showing, G, an outer layer which is more or less easily separable from the rest of the seed and the walls of which are somewhat mucilaginous; E, epidermis of palisade-like cells; Sc. sclerotic cells; PI, a layer of tabular cells with undulate walls; T, a layer of small somewhat branching cells, the walls of which are not strongly thickened and either porous or reticulate; P, several layers of parenchyma and the collapsed epidermis; Pe, perisperm; En, endosperm. E, tangential section of tabular sclerotic cells of seed-coat shown in PI in Fig. D. — After Meyer. around the wall of the embryo-sac, divide and re-divide; the large vacuole in the center becomes filled with a watery or milky fluid, and later the nuclei, with portions of the cytoplasm, may be enclosed by a cellulose wall and become permanent cells, in which the embryo is embedded. Likewise in the nucellus, changes are also taking place ; the cells are found to be dividing, and storing starch, oil, aleurone, and other food materials, like the cells of the MORPHOLOGY OF HIGHER PLANTS. 425 embryo-sac. The cells in which these materials are stored are known as reserve cells, and in the nucellus they constitute the PERISPERM, while those formed in the embryo-sac make up the ENDOSPERM. Usually the endosperm of seeds is prominently de- veloped, while the perisperm occurs as a thin layer ; in some seeds, however, the endosperm and perisperm are both well developed. In some instances the embryo may not fill the embryo-sac, as in cocoanut, and sometimes, as in the almond, both of the reserve layers are consumed in the development of the embryo, when the seed is said to be without endosperm (Fig. 248'). The perisperm and endosperm are sometimes spoken of to- gether as the albumen of the seed, but as the cells comprised in these layers contain not only protoplasmic contents and aleurone grains, but starches, oils, and other substances, the term is mis- leading. On this basis, seeds containing either endosperm or perisperm, or both, have been designated as albuminous, but on account of these layers containing larger proportions of other substances than proteins it would be better to speak of them as RESERVE LAYERS ( FigS. 247, 250). While these changes in the nucellus and embryo-sac have been going on there have been equally great changes in the coats of the ovules, which develop into the seed-coats. In the seed the two coats are generally readily distinguishable. The inner, as in Ricimis, Pepo, etc., is thin, light in color, of a delicate structure, and is known as the TEGAIEN ; the outer is more or less thickened, of a darker color and firmer in structure, and is known as the TESTA. In some instances the perisperm, or both perisperm and endosperm, may be reduced to a thin layer when it is considered to form a part of the seed-coat, as in mustard. In other cases the two coats are so closely united that they are not easily distin- guished, as in stramonium. The terms used in describing the kinds of ovules (atropous, anatropous, campylotropous, etc.) are retained in the description of the seeds ; and in describing the different parts of the seed some of the terms which were applied to the ovule are also retained, as chalaza and raphe ; the seed when ripe usually becomes detached from its stalk, and the resulting scar is called the HILUM ; that part of the seed corresponding to the foramen of the ovule is more or less closed and is known as the MICROPYLE; the embryo 426 A TEXT-BOOK OF LiOTAXY. develops in such a way that the tip of the young root always points in the direction of the micropyle. In the fully developed embryo three distinct parts may he dif- ferentiated (Fig. 161) : (i) The COTYLEDONS; (2) the part below the cotyledons, known as the HYPOCOTYL, the apical portion of which constitutes the young root or RADICLE; ^(3) the part above car per li FIG. 249. Forms of embryo and distribution of endosperm in various seeds and fruits. A, Ricinus seed: car, caruncle; m, micropyle; e, embryo. B, superior drupe ot Piper: per, pericarp; e, endosperm; p, perisperm. C, spinach fruit and D, corn cockle seed (Agrostemma Githago): per, pericarp; t, seed-coat; h, hilum; p, perisperm; e, endosperm c, curved embryo. — A, C, D, after Harz; B, after Baillon. the cotyledons, known as the EPICOTYL, the apex of which con- sists of a more or less developed bud spoken of as the PLUMULE. The position of the embryo (Figs. 249, 250) in the seed varies somewhat : in most seeds it lies in the center, as in strophanthus and linum ; it may, however, be excentral, as in colchicum and nutmeg. The cotyledons are usually situated above the hypocotyl, but in the Cruciferae, either their edges lie against the hypocotyl, as in the mustards, when they are said to be ACCUMBENT or con- MORPHOLOGY OF HIGHER PLANTS. 427 duplicate, or they lie so that the back of one is against the hypo- cotyl, as in Lepidium, which position is known as INCUMBENT. Externally, the seed-coats vary considerably ; they may be nearly smooth, as in ricinus ; finely pitted, as in the mustards ; prominently reticulate, as in staphisagria ; hairy, as in cotton, strophanthus, and apocynum (Fig. 251) ; or winged, as in the seeds of the catalpa. There are also a number of other appendages, these having received special names : the wart-like development at the micropyle or hilum of some seeds, as in castor-bean and violet, is known as the CARUNCLE; in the case of sanguinaria, a wing-like development extends along the raphe, and this is known as the STROPHIOLE ; in some cases the appendage may completely envelop the seed, when it is termed an ARILLUS ; when such an envelope arises at or near the micropyle of the seed, as the mace in nutmeg, it is known as a " false arillus," or ARILLODE. Seed Dispersal. — Seeds and fruits are distributed in various ways, and so are often found growing in localities far from their native habitat. In some instances seeds are adapted for distribu- tion by the wind, being winged, as in Pauloivnia, Catalpa, and Bignonia, or plumed and awned, as in Strophanthus Kombe, Asclcpias,3.nd Apocynum (Fig. 251). As examples of fruits hav- ing special parts which aid in their distribution may be mentioned the achene of Taraxacum which is provided with a pappus (Fig. 227), the bladder-like pericarp of Chenopodium, and the winged fruit or samara of maple. The hooked or barbed appendages on some fruits serve to attach them to animals, and thus they may be widely distributed, as in the burdock and Spanish needles (Bid ens bipinnata). In still other cases fruits may be carried long distances by water currents, or even by ocean currents, as those of thej Double-cocoanut palm (Lodoicea sechellanun), which while native of the Seychelles Islands is now found on many of the islands in the Pacific and Indian Oceans. It may also be mentioned in this connection that a number of fruits, as the garden balsam, castor-oil plant, violets (pansy, etc.), Wistaria, etc., are elastically dehiscent and discharge the seeds with considerable force. THE INNER STRUCTURE OF THE SEED. The SEED-COAT usually consists of from two to six layers of cells: (i) an outer layer or so-called epidermis, (2) a layer of 428 A TEXT-BOOK OF BOTANY. sclerenchymatous cells or stone cells, (3) a pigment layer, (4, 5) one or two rows of parenchymatous cells, (6) a row of more or less obliterated parenchyma cells. The EPIDERMAL CELLS vary considerably in different species H M D FIG. 250. A. — Longitudinal section through anatropous seed of linum: R, raphe; SC, seed-coat; M, hilum; H, micropyle; EN, endosperm; C, cotyledon; HY, hypocotyl. B. — Longitudinal section through stramonium seed: SC, seed-coat; H, micropyle; M, hilum; EN, endosperm; E, curved embryo. C. — Transverse section through endosperm of nux vomica showing thick-walled parenchyma, the cells containing oil and protoplasm. D. — Transverse section through endosperm of seed of Ricinus communis, one cell filled with aleurone grainr, each with a crystalloid and globoid, and another in which the aleurone grains have been dissolved, the cytoplasm and nucleus remaining. both as regards the form of the cells and the composition of the walls (Fig. 136). The cells may be more or less isodiametric in cross-section, as in cardamom (see Vol. II) ; elliptical, as in almond (Fig. 136, D) ; palisade-like, as in Abrus prccatorius, or more or MORPHOLOGY OF HIGHER PLANTS. 429 less irregular, as in Delphinium. While the outer and side walls are usually thickened, in hyoscyamus (Fig. 251), it is the inner and side walls which are thickened, the outer wall remaining thin. The outer wall may be in part modified to mucilage, as in mustard and flaxseed (Fig. 119) ; or to non-glandular hairs which consist either of cellulose, as in cotton (Fig. 139), or lignocellulose, as in nux vomica (Fig. 119). The PERISPERM and ENDOSPERM (Fig. 249) consist chiefly of parenchyma cells, which contain, besides protoplasm, starch, as FIG. 251. Seeds: A, of Hyoscyamus muticus with epidermal cells having wavy, thick- ened walls, those at the edge are seen in section and showing that the outer wall is not thickened. B, of Lobelia inflata showing reticulate seed-coat composed of uniformly thick- ened and strongly lignified cells. C, of Apocynum cannabinum with numerous long i-celled hyaline hairs. in physostigma ; oil, as in flaxseed and cottonseed ; aleurone grains, as in ricinus (Fig. 250); glucosides, as in almond; alkaloids, as in stramonium. The walls are usually thin, but may in some instances be considerably thickened, as in coffee, colchicum, and nux vomica (Fig. 135). The embryo consists chiefly of parenchyma cells with a few fibrovascular bundles : the cotyledons may be thin and leaf-like, as in ricinus and nux vomica, or thick and fleshy, as in almond and cola, or partly developed, as in strophanthus ; the hypocotyl is usually small, but in the Umbelliferse it is as large as the cotyledons. CHAPTER IV. BOTANICAL NOMENCLATURE. LET the student consult the various manuals on Botany and even some of the larger authoritative works and he will be imme- diately impressed that there is more or less confusion concerning the names of certain plants. For instance, in looking up the botanical origin of the False Solomon's Seal, one author will give it as Siuilacina raccmosa, while another writer will use the name of Vagncra raccuiosa. Again, if the student desires to use the correct family name he will be confused both as to the correct spelling of the name as well as the name of the family itself, the Grass Family being given as Graminacese or Graminese ; the Leguminosas may be divided into the Mimosacere, Qesalpinaceae and Papilionacese. At first thought it might seem that this incon- sistency is peculiar to botanical science, but as a matter of fact we find the same difficulties in the language of other sciences. This confusion is due to the fact that up until now there has not been an international agreement or even one of a national character regarding the rules to be observed in botanical nomenclature. 1 For many decades it has been almost universally felt that botanical nomenclature should rest in a general way on the prin- ciple of priority of publication, or, in other words, that the name of a plant was the first one assigned to it. Nearly all botanists of note have readily assented to this general idea, but great difficulties have arisen regarding the precise limitations which should be imposed upon the principle. Thus, botanists of past generations, including such great leaders as the De Candolles, Bentham, the Hookers, Gray, von Martins, Eichler, Baillon, and others, have followed the principle of priority, yet they have made frequent exceptions based on considerations of taste and convenience as well as practicality." With the expansion of the subject the difficulty of agreement on these exceptions has increased, and some recent writers have been disposed at times to criticise rather harshly the earlier bot- anists for making any exceptions whatever. It should be noticed, 430 BOTANICAL NOMENCLATURE. 431 however, that even the more strenuous of these reformers them- selves admit certain exceptions. They have found it necessary, for instance, to fix initial dates, and to rule out certain names as too vague in their definition or too uncouth in their form to be accepted." Ideas as to the best mode of establishing rules or reaching a general agreement regarding the necessary exceptions to the bald principle of priority have differed widely and given rise to lively controversy. To some it has seemed best to advise an ideal system and then, without much reference to the wishes or convenience of their colleagues, to apply it in local publication. To the vast majority, however, it has been clear that the subject was a broad one, involving much mutual sacrifice before the now divergent usages at different botanical centers could be brought into har- mony. The question is also an international one, requiring the botanists of different nations to attain a common agreement. For some years there was a growing desire for an international meet- ing of representative botanists who should give the matter of nomenclature careful consideration and come, if possible, to some agreement on the fundamental rules to be followed. This feeling took definite form in the year 1900, when preliminary sessions of such a gathering were held in connection with the Paris Congress of Botanists. At this meeting a bureau was formed for the organization of an International Botanical Con- gress to be held at Vienna in June, 1905." This congress convened in Vienna and was attended by between five and six hundred bota- nists, representing the leading botanical institutions of the world. They framed international rules which should be used in the botanical nomenclature of vascular plants, and a complete list of these will be found in Rlwdora, the journal of the New England Botanical Club, for March, 1907. A few of the general considerations and leading principles will be mentioned, however, in order that the student may have some understanding of the subject. According to the Vienna Congress, the prescriptions, which should govern the system of botanical nomenclature, are divided into (i) principles, (2) rules, and (3) recommendations. Among the principles that should be adhered to is that scientific 432 A TEXT-BOOK OF BOTANY. names are to be in Latin for all groups. When taken from another language, a Latin termination is given them, except in cases sanctioned by custom. If translated into a modern language, it is desirable that they should preserve as great a resemblance as possible to the original Latin names. Among the rules to be followed in designating the nature and the subordination of the several groups, the following were adopted : Every individual plant belongs to a species (species), every species to a genus (genus), every genus to a family (familia), every family to an order (ordo), every order to a class (classis), every class to a division (divisio). In a number of species varie- ties and forms are also distinguished. In some cultivated species there are unlimited modifications. The crossing of one species \vith another species gives rise to a hybrid. Regarding the point of nomenclature and limitation of principle of priority, it was agreed at the congress that botanical nomen- clature should begin with the Species Plantarum of Linnaeus, ed. i (1753), for all groups of vascular plants. It was further agreed to associate genera, the names of which appear in this work, with descriptions given of them by him in his Genera Plan- tarum, ed. 5 (1754). However, to avoid disadvantageous changes in the nomenclature of genera by the strict application of the rules of nomenclature, and especially of the principle of priority in starting from 1753, the rules provide a list of names which must be retained in all cases. These names are by preference those which have come into general use in the fifty years following their publication, or which have been used in monographs and important floristic works up to the year 1890. Among the recommendations, the following suggestions were made in regard to the nomenclature of divisions, classes, families, genera, and species : i. Names of divisions and subdivisions, of classes and sub- classes are taken from one of their characters. They are expressed by words of Greek or Latin origin, some similarity of form and termination being given to those that designate groups of the same nature, as Angiospermse, Gymnospermse ; Monocotyledoneae, Di- cotyledoneae ; Coni ferae; Pteridophyta. Among Cryptogams old BOTANICAL NOMENCLATURE. 433 family names such as Fungi, Lichenes, Algae, may be used for names of groups above the rank of family. 2. Orders are designated preferably by the name of one of their principal families, with the ending -ales, e.g., Polygonales from Polygonaceae. Suborders are designated in a similar manner, with the ending -ineae, e.g., Malvineae from Malvaceae. But other terminations may be retained for these names, provided that they do not lead to confusion or error. 3. The names of families are designated by the name of one of their genera or ancient generic names with the ending -aceae, e.g., Rosaceae from Rosa, etc. The following names, owing to long usage, are an exception to the rule : Palmae, Gramineae, Cruciferae, Leguminosae, Guttiferae, Umbelliferae, Labiatae, and Compositae. 4. The names of genera should be substantives (or adjectives used as substantives) in the singular number and written with a capital letter, which may be compared with our own family names. These names may be taken from any source whatever and may even be composed in an absolutely arbitrary manner, as Rosa, Convolvulus, Liquidambar, Impatiens, and Manihot. 5. The names of all species, even those that singly constitute a genus, are designated by the name of the genus to which they be- long, followed by a name (or epithet) termed specific, usually of the nature of an adjective (forming a combination of two names, a binomial, or binary name). The specific name should, in general, give some indication of the appearance, the characters, the origin, the history, or the properties of the species. If taken from the name of a person, it usually recalls the name of the one who discov- ered or described it, or was in some way concerned with it. Specific names begin with a small letter, except those which are taken f rom names of persons or those which are taken from generic names. The student should endeavor to fix in mind the general prin- ciples concerning botanical nomenclature and should devote special attention to the generic and specific names and the rules which govern their formation. In addition he should familiarize himself with the meaning of the names, as this will enable him to memorize and spell them correctly. The following is a partial list of some of the principal generic and specific names, giving as far as possible the origin of the names and their significance : 28 434 A TEXT-BOOK OF BOTANY. Abelmoschus. Muskmallow. From Arab. Abu-l-misk, father of musk; producing musk. Abies. Fir. The classical Latin name. Abrotanum. Southernwood. Gr. aflpoTovov ; from appoToc, sacred to the gods, immortal ; probably in allusion to the odor. Abrus. Indian licorice. From Gr. a/3/>6^) graceful ; in allusion to the flowers. Absinthium. Wormwood. The ancient Greek name. Abyssinicus-a-um. Pertaining to Abyssinia. Acacia. The ancient Greek name of an Egyptian species. From drf, a point; referring to the thorns. Acer. Maple. The classical Latin name. Acer, acris, acre. Sharp, pungent. From root ak, to be sharp. Achillea. Yarrow, Milfoil. Named for the Greek warrior Achilles, who is said to have discovered the virtues of the plant. Aconitum. Monkshood, Wolfsbane. The ancient Greek name. Acorus. Sweet flag. The ancient classical name. Actsea. Baneberry, Cohosh. Ancient Greek name of the elder. Acuminatus-a-um. Acuminate, tapering. Lat. acumino, to make pointed. Acutifolius-a-um. Having sharp-pointed leaves. Lat. acutiis, sharp, ~h folium, a leaf. Adiantum. Maidenhair. The ancient name. From Gr. a priv., + dtaivu, to wet, hence unwetted, incapable of being wet. Adonis. Pheasant's eye. A plant fabled to have sprung from the blood of the beautiful Adonis. Advena. Yellow pond lily. From Lat. advena, strange, foreign. (Of doubtful application.) Aegle. Bengal quince. Name of a nymph in Greek mythology. Perhaps from al-yTi?], brightness, splendor. ^isculus. Horsechestnut. The Latin name of an oak or some other mast- bearing tree, ^stivalis-e. Pertaining to the summer. The classical Latin word is crstivalis. Agaricus. Mushrooms. Gr. ayapiKov. Lat. agariciiin. a tree fungus. Agave. American aloe. Gr. ayavij, noble, illustrious. Appropriately applied to Agave amcricana, the century plant. Agrimonia. Probably a corruption from argemonc. According to others, it is derived from Gr. o}pof, field, + /^droc, alone. Agropyron. Wheat grass. From Gr. aypoc, field, + Trvp6<;, wheat ; alluding to the fact that it grows wild in wheat fields. Agrostemma. Corn cockle. From Gr. aypdc, field, + ar/////«, a crown. Ailanthus. Tree of heaven. Said to be from aylanto, the name of the tree in the Moluccas, in allusion to its height. Ajuga. Bugle weed. From Gr. a priv., + Cvyov (Lat. iuguni}, a yoke. From the fact that the lower lip of the corolla has a single, con- spicuous middle lobe. BOTANICAL NOMENCLATURE. 435 Albizzia. Name derived from the Albizzi, a noble family of Italy, one of whom is said to have introduced this genus into European culti- vation. Albus-a-um. White. Alchemilla. Lady's mantle. From the Arabic name alkemelyeh; in refer- ence to the silky pubescence of some species. Aletris. Star grass, Colic-root. From Gr. a/erp/f, a female slave who grinds ; in allusion to the mealy appearance of the blossoms. Algae. Plural of alga, sea-weed; probably a shortened form of alliga, from ad, to, + ligo, to bind. Allium. Onion, Garlic. The ancient Latin name for garlic ; perhaps con- nected with Lat. oleo, to emit a smell. Alnus. Alder. The ancient Latin name. Aloe. The ancient Greek name. Alsine. Chickweed. Greek name of a plant. Alstonia. Dita. Named for Dr. Charles Alston, botanist, of Edinburgh (1683-1760). Althaea. Marshmallow. Hollyhock. The classical name. From Gr. aWaivu, to heal, cure ; in allusion to the medicinal properties of the plant. Alyssum. Greek name of a plant believed to check hydrophobia ; from a priv., + "Xvcaa, raging madness. Or a plant used to check hiccup ; from a priv., + ^i^y, to have the hiccup. Amaranthus. Amaranth. From Gr.d^dpa^rof, unfading; because the bracts are dry and persistent. Amarus-a-um. Bitter. Amaryllis. Belladonna lily. Greek name of a shepherdess. Ambrosia. Ragweed. The Greek and Latin name of several plants, as well as of the food of the immortals. Ambrosioides. Gr. apfipoaia -\- o- ea%? like, resembling ambrosia. Americanus-a-um. Belonging to America. Ammania. Named for Paul Ammann, a German botanist prior to Linnaeus. Ammoniacum. A resinous gum which exudes from a tree that grew near the temple of Jupiter Ammon. The Greek name. Amomum. Cardamom. Greek name of an Indian spice plant. Amorpha. False indigo. From Gr. a/2op0#, form ; in allusion to the absence of four of the petals. Amygdalus. Almond. Peach. Ancient Greek name. From aftvacru, to tear, rend ; in allusion to the furrows on the endocarp. Amylum. Starch. The Greek name. From a, priv., + A"'^, a mill ; re- ferring to its fineness, which makes it unnecessary for it to be ground. Anacardium. Cashew. From Gr. avd9 similar to, + Kapdia, heart. The fruit of the plant is thought to resemble the heart of a bird. Anacyclus. Pellitory. An abbreviation for ananthocyclus. From Gr. a priv., -f- drflof, flower, -f- KVK'AOI;, circle ; in allusion to the pistillate or infertile rays. Meaning rather vague. 436 A TEXT-BOOK OF BOTAXY. Anagallis. Pimpernel. The ancient Greek name. Probably fro.m again, + ayd\\w, to delight in. Anamirta. An Indian name synonymous with Menispermum. Ananas. Pineapple. Sp. ananas, from the native American name. Andira. Vouacapoua. From the vernacular Brazilian name. Andropogon. Beard grass. From avr/p, avfipoq, man, + TTWJ-WV, beard. Anemone. Wind flower. The ancient Greek name. From dvf^oc, wind. Anethum. Dill. The ancient Greek name. Probably related to avtaov, anise. Angelica. From Gr. ayye^of, messenger, angel ; in allusion to its cordial and medicinal properties. Angostura. Name of a city in Venezuela, whence angustura bark is im- ported. Angustifolius-a-um. Having narrow leaves. From Lat. angustus, narrow, + folium, leaf. Anisum. Anise. Gr. aviaov, avrjBov* Annuus-a-um. Of one year's duration. Lat. annus, a year. Anogra. Evening primrose. Name formed by transposition of letters of Onagra, another name for this plant. Anthelminticus-a-um. Worm-destroying. From Gr. avri, against, -f- eh/Mv5, worm. Anthemis. The ancient Greek name of chamomile. Anthoxanthum. Sweet vernal grass. From Gr. avftoc, flower, -\- £avflof? yellow. Aparine. Cleaverwort. The ancient Greek name of a plant. Apocynum. Dogbane. Indian Hemp. The classical name. From OTTO, from, + KVUV, dog. Aquaticus-a-um. Growing in or by the water. Aquifolium. Holly-leaved barberry. Ancient Latin name for the holly tree or the scarlet holm. Arabicus-a-um. Pertaining to Arabia. Aralia. Derivation of name unknown. Araroba. From East Indian name ar(ar}oba as applied to the bark. Arctium. Burdock. From Gr. apic-of, a bear, or apttnov, a plant. Arctostaphylos. Bearberry. From Gr. d/j/crof, a bear, -f- craov/.i/, a bunch of grapes. Areca. Betel-nut. Sp. and Port, areca, from East Indian vernacular name. Argemone. Prickly poppy. The ancient Greek name for poppy. Accord- ing to others, from a/r/r/Lia, a disease of the eye, for which the juice of a plant s*o called by the Greeks was a supposed remedy. Argithamnia. From Gr. apyvpos, silver, + 6d/uvo£, bush ; from the hoari- ness of the original species. ArisaMna. Indian turnip. From Gr. api<;, a kind of arum, -f- at pa, blood; from the spotted leaves of some species. Aristolochia. Birthwort. From Gr. apiaros, best, + Ao^e/a, child-birth; once thought to ease labor. BOTANICAL NOMENCLATURE. 437 Arnica. From Gr. d^va;c/?, sheepskin, Lat. arnacis, a coat of sheepskin; in reference to the hairy stem and leaves ; or, according to others, from Gi". TTTapjLiiKos, Lat. ptarmicus, causing to sneeze. Aromaticus-a-um. Aromatic, fragrant. Artemisia. Wormwood, ancient Greek name of an herb. From the queen Artemisia, wife of Mausolus. Artemisiaefolius-a-um. Having leaves resembling those of Artemisia. Artocarpus. Breadfruit. From Gr. aprog, bread, + napTrog, fruit. Arum. Also Aron. The ancient Greek name apov. Arundinaceus-a-um. Reed-like. From Lat. arundo, a reed. Arvensis-e. Cultivated. From Lat. arva, an arable field. Asagraea. From Asa Gray, the eminent American botanist. Asarum. Hazelwort, Wild ginger. The ancient Greek name. Asclepias. Milkweed, Silkweed. Named in honor of /Esculapius, the Latin tutelary god of medicine. Asimina. North American papaw. The Northern Algonkin corruption of rassimina, in allusion to the shape of the fruit. Asparagus. From the ancient Greek name ao-irapayog, asparagus. Asperula. Woodruff weed. From Lat. aspcr, rough ; in allusion to some scabrous species. Aspidium. Shield fern. From Gr. aajritiiov, a little shield ; from the shape of the indusium. Aspidosperma. From Gr. GKTTT/C, a shield, -\- a-rep/ua, seed ; from the shape of the seed. Asplenium. Spleenwort. From Gr. a priv., -f- ffTrAr/v, the spleen ; because of its supposed remedial properties. Astragalus. Milk vetch. Gr. aarpdyaAog, a leguminous plant. Athamanticus-a-um. Of Athamas, a mountain in Thessaly ; with reference to the habitat of the plant. Atriplex. The ancient Latin name for orach; a corruption of the Greek Atropa. Name from "ArpoTroc, one of the Greek Fates ; from a priv., + rpoTTj?, a turn ; hence unchangeable, inflexible. Atropurpureus-a-um. From Lat. atcr, dark, -)- purpurciis, purple; dark purple. Aurantium. Orange. From Lat. aurum, gold, referring to the color of the fruit. Australis-e. Southern. Lat. auster, the South wind. Autumnalis-e. In the autumn ; referring to the time of blooming. Avena. Oats. The classical Latin name. Baccharis. Groundsel tree. The classical name of a shrub dedicated to Bacchus. Baccifer-a-um. Producing berries. Lat. bacca, a berry, + fero, to bear. Ballota. Fetid horehound. The ancient Greek name. 438 A TEXT-BOOK OF BOTANY. Balsamifer-a-um. Producing balsam. Lat. balsamum, balsam, + fero, to bear. Balsamum-ea. The classical name of the several trees yielding a balsam; also in allusion to the balsamic oleo-resins obtained from the trees. Baptisia. False indigo. From Gr. /fan-r^w, to dye. Barbarea. Winter cress. Anciently called the Herb of St. Barbara. Barosma. Buchu. From Gr. /fa/ji-?, heavy, + oa^} odor ; in reference to its strong smell. Belladonna. Ital. bell a, beautiful, -f donna, lady. It is said that Italian ladies used the berries as a cosmetic and to dilate the pupil of the eye, thus giving themselves a striking appearance. Benedictus-a-um. Blessed, consecrated. Past participle of Lat. benedico, to bless. Benzoin. Wild allspice. Fever bush. Named from its odor, which resem- bles that of benzoinum. Benzoinum. A resinous substance from Styra.y Benzoin, a tree of Sumatra, Java. French bcnjoin, from Arabic luban-jawi, incense of Java. Berberis. Barberry. Name derived from bcrberys, the Arabic name of the fruit. Beta. Beet. The ancient Latin name. Betonica. Betony. The ancient Latin name (betonica, vettonica) of wood betony. Betula. Birch. The ancient Latin name. Betulinus-a-um. Pertaining to birch ; alluding to the fact that the leaves resemble birch leaves. Bidens. Bur marigold. From Lat. bidcns, two-toothed. Biennis-e. Of two years' duration. Lat. bis, twice, + annns, year. Biflorus-a-um. Bearing two flowers, biflorate. Bignonia. Named for the Abbe Jean Paul Bignon, court-librarian at Paris and friend of Tournefort. Bistorta. Adderswort. From bis, twice, + tortus (past participle of tor- queo}, twisted. Boehmeria. False nettle. Named after G. R. Boehmer, German botanist and professor at Wittenberg in the eighteenth century. Botrychium. Moonwort. From Gr. /3drpi»f, a bunch of grapes; from the appearance of the fructification. Brachycerus-a-um. Having short horns. From Gr. Ppaxi'c, short, -f- •fcfyrtf, a horn. • Brasiliensis-e. Belonging to Brazil. Brassica. Mustard. Turnip. The ancient Latin name for cabbage. Brauneria. Purple cone-flower. Named for Jacob Brauner, German botanist of the eighteenth century. Bryonia. Bryony. The ancient Greek name. From /3/ww, to swell, grow luxuriantly. Bursa. Capsella. Bursa is a late Latin word meaning purse. BOTANICAL NOMENCLATURE. 439 Bursa-pastoris. Shepherd's purse. Butneria. Spice bush. Buxus. Boxwood. The ancient Latin name. Gr. Tri'fof. Cacao. Span, from Mex. kakahuatl; native name of the tree Theobroma Cacao. Cactus. The ancient Greek name of some thorny plant. Csesalpinia. Sappan. Named for Andreas Csesalpinus, Italian botanist, who died in 1603. Cajuputi. Name of Malayan origin. From kayu, tree, -\-putih, white; in reference to the appearance of the branches. Calamus. Reed, cane. The classical word. So named because its scape is reed-like. Calendula. Marigold. Lat. calender, calends, the first day of the month; so called because it flowers every month. Californicus-a-um. Pertaining to California. Calisaya. A name given to the bark of a tree of Peru by Spaniards and Indians. Calla. Water arum. Linnaeus derived calla from Gr. KdAAam, a cock's wattles, but compare Lat. calla, calsa, name of an unknown plant, and Greek /ca/o'f, beautiful. Calluna. Heather. From Gr. /caA/luvw, to brush or sweep, brooms being made from the twigs. Calophyllum. Tacamahac. From Gr. /caAdf, beautiful, + fyvXhov, a leaf. Caltha. Marsh marigold. An ancient Latin name for the common mari- gold. Calumba. From kalumb, its native name in Mozambique. Cambogia. From Cambodia, a French protectorate in Farther India. Camelina. False flax. From Gr. x0-^0-'1, dwarf, -j- JUvov, flax. Campechianus-a-um. Belonging to Campeachy. Campestris-e. Growing in uncultivated fields. Camphora. Gr. Katyovpa, from Arab, kafur, camphor. Camptosorus. Walking leaf. From Gr. /ca//7rrdf, flexible, + aupo^ sorus, fruit dot. Canadensis-e. Of or belonging to Canada. Cannabinus-a-um. Pertaining to cannabis. Cannabis. Hemp. The ancient Greek name. Caoutchouc. Native South American name for the milky sap of several plants. Also called India rubber. Capillaceus-a-um. Hairy, very slender, like a hair. From Lat. capillus, hair. Capillus-Veneris. Maidenhair. The Latin for hair of Venus. Capsella. Shepherd's purse. Diminutive of capsa, a box. Capsicum. Red pepper. From Lat. capsa, a box; alluding to the shape of the fruit. Or from Gr. /ca/rrw, to bite, from its hot, pungent properties. Cardamomum. The ancient classical name for the spice cardamom. Carex. Sedge. The ancient Latin name. 440 A TEXT-BOOK OF BOTAXY. Carica. Papaw. The Latin name for dried fig, from Caria, in Asia Minor. Carolinensis-e. i Carolinianus-a-um. } BelonSin§ to Carolina. Carota. Carrot. The classical Latin word. Carpinus. Hornbeam. The ancient Latin name. Carum. Caraway. Gr. ndpov, Lat. careum. Probably from Caria, in Asia Minor. Carvi or Carui. Probably an assimilated Latin genitive, as in Carui scmina. Caryophyllus. Cloves. From Gr. napvovt nut, -f- vMov} a leaf ; a stem-leaf. Ceanothus. Red root. Gr. Ksdvufios, a kind of thistle. Cedron. Cedron seed. From Gr. Ktrfpov, the fruit of the cedar. Celastrus. Staff tree. The ancient Greek name of an evergreen tree. Centaurea. Star thistle. Ancient Greek name of a plant. The plant of the Centaurs. Centifolius-a-um. Having a hundred leaves or petals. From Lat. centum, hundred, -f- fo Hum, a leaf. Cephaelis. Ipecacuanha. From Gr. Kefa'/.?/, head, + ei/w, to collect, roll up. The flowers are collected into a capitulum. Cephalanthus. Buttonbush. From Gr. Kt-pa/f/, head, -f- arflof, flower. Flowers aggregated in spherical peduncled heads. Ceratonia. St. John's bread. Greek name for the carrob or locust tree. From ttepaq, a horn ; alluding to the horn-shaped pods. Cerealis-e. Pertaining to grain or agriculture. From Ceres, the Latin goddess of agriculture. Cetraria. Iceland moss. From Lat. ccctra, a shield ; in reference to the shield-shaped apothecia. Chamsenerion. Willow-herb. From Gr. ^a^iat, on the ground, + vi/ptov, rose-laurel. Chamomilla. Earth apple. From Gr. xana>, on the earth, + //7/Aov, an apple. From the apple-like odor of the flowers. BOTANICAL NOMENCLATURE. 441 Chekan. The Chilian name of Eugenia Chckan. Chelidonium. Celandine. From Gr. ^e/lidwv, a swallow, the flowers appearing at the same time as the swallows. Chelone. Turtlehead. Snakehead. From Gr. X£^UVT/, a tortoise, the corolla being shaped like the head of a reptile. Chenopodium. Goosefoot. Pigweed. The ancient Greek name. From Xt'jVy goose, + Troi'f , foot. Chimaphila. Pipsissewa. Bitter wintergreen. Love-in-winter. From Gr. Xet/J-a, winter, + 0'^ew, to love ; in allusion to the several popular names. Chionanthus. Fringe-tree. From Gr.. xi&v, snow, -f av0o£t flower; in refer- ence to the snow-white clusters of the flowers. Chirata or Chirayita. From the Hindoo name chiraita. Chondrodendron. From Gr. ^dvdpof, /a granule + divSpov, a tree ; allud- ing to the warty protuberances on the bark. Chondrus. Sea moss. From Gr. ^dt-Jpof, cartilage ; in reference to the cartilaginous fronds. Chrysanthemum. Gold-flower. The ancient Greek name. Chrysarobinum. From Gr. xPva°ff, gold, + araroba, a foreign name of Gca powder. Chrysophyllum. Star apple. From Gr. ^pucrdc, gold, -f ^Aov, leaf. Chrysosplenium. Golden saxifrage. From Gr. xpvadc, gold, -f- airMjv, the spleen. From its reputed medicinal properties. Cichorium. Gr. K/jopa, 'Succory, Chicory. Cicuta. Water hemlock. The ancient Latin name of the hemlock. Cimicifuga. Bugbane. From Lat. cime.r, a bug, + fugo, to drive away. Cinchona. Named for the countess of Chinchon, who brought the remedy to Europe, when she returned with her husband, viceroy of Peru, in 1640. Cinereus-a-um. Ash-colored. From Lat. cinis, ashes. Cinnamomum. Cinnamon. The classical name. Circaea. Enchanter's nightshade. Named after the enchantress Circe. Cissampelos. From Gr. utatjos, ivy, + a/zTre/lof, vine. From the fact that it climbs like the ivy. Citrullus. Melon. From Lat. citrus, the citron tree. Citrus. Citron, Orange. The Latin name for the citron tree. Clava-Kerculis. Club of Hercules ; from the appearance of the cone-like cork-wings. Clavatus-a-um. Club-like. From clava, a club. Claviceps. Ergot. From Lat. clava, a club, + caput, head; alluding to the shape of the mycelium or sclerotium. Clematis. Virgin's bower. Greek name of a creeping plant with long, lithe branches. Probably clematis or periwinkle. Clinopodium. Field thyme. Calamint. From Gr. KAhq, a bed, + TTOI-C, foot. Clove. From Lat. clavus, a nail ; in allusion to the shape of the dried fruit. 442 A TEXT-BOOK OF BOTAXY. Cnicus. Blessed thistle. Latin name of the safflower, from the Gr. Coca. Span, from native name of tree. Cocculus. Diminutive of coccus, a berry. Cochlearia. Scurvy grass. From Gr. nnx'-idpiov, a spoon ; with reference to the shape of the leaves. Coffea. Coffee. From Turk, qahvch, Arab, qahuah, name of a beverage. Colchicum. Meadow saffron. From Gr. Kohx'G, Colchis, an ancient province in Asia Minor, where this plant flourished. Collinsonia. Horsebalm. Named in honor of Peter Collinson, English botanist of the eighteenth century. Colocynthis. From Gr. KoAoKvvOq, a gourd or pumpkin. Commelina. Day-flower. Named after the Dutch botanists J. and G. Commelin, who lived in the seventeenth century. Commiphora. Myrrh. From Gr. KOfi/m, gum, -{- popo^, bearing ; in allusion to the exudation. Communis-e. Common, general. Conifer-a-um. From Lat. conns, a cone, -+- fcro, to bear, cone-bearing. Conium. Poison hemlock. From nuvetov, the Greek word for hemlock. Convallaria. Lily of the valley. From Lat. convallis, a valley. Convolvulus. Bindweed. The ancient Latin name from convolve, to entwine. Copaiba. Span, and Port, from Brazil, cupauba, the native name of the tree and its product. Coptis. Goldthread. From Gr. /COTT-W, to cut ; in allusion to the divided leaves. Corallorhiza. Coral root. From Gr. xopdMiov, coral, -j- /u(a, root. Cordifolius-a-um. Heart-leafed. From Lat. cor, cordis, heart, -f- folium, leaf. Coriandrum. Coriander. The ancient Latin name, from Gr. Kopiavvov. Coriarious-a-um. Pertaining to leather. Lat. corium, leather. Cornus. Cornel. Dogwood. From Lat. cornu, a horn ; alluding to the hardness of the wood. Coronilla. Axseed. Diminutive of Lat. corona, a crown ; alluding to the inflorescence. Corylus. Hazelnut, Filbert. The classical name. Probably from Gr. nopvs, a helmet, from the helmet-like involucre. Cotula. Mayweed. From Gr. /corr/T?, a hollow. Crataegus. Hawthorn. The Greek name of a kind of flowering thorn. Perhaps derived from /cpd-of, strength. Crenulatus-a-um. Notched. From crcna, a notch, referring to the leaves. Crispus-a-um. Curled, crisped. Crocus. Saffron. The ancient Greek name. According to mythology, a youth, Crocus, was changed into this flower. Crotalaria. Rattle-box. From Gr. ttpoTa/.ov, a rattle ; from the rattling of the loose seeds in the pod. BOTANICAL NOMENCLATURE. 443 Croton. From Gr. uporuv or Kp6rcjv} a tick, because the seed was thought to resemble a tick. Also applied to the castor-oil seed. Crucifer-a-um. Cross-bearing. From Lat. crux, cross, -f fcro, to bear. With reference to the form of the flowers. Cruciger-a-um. Cross-bearing. From Lat. crux, cross, + gcro, to bear. Cubeba. Span, and Port, from Arab, kababat, native name of the plant. Cucumis. Cucumber Melon. The ancient Latin name. Cucurbita. Gourd, Squash. The ancient Latin name. Cuminum. Cumin. The ancient Greek name. Cunila. Dittany. Ancient Latin name for a plant, a species of orizanum. Cupana. After Father Francis Cupani, Italian monk and botanist; died in 1710. Cusparia. Angostura. Cusso. Abyssinian name of the tree Hagenia Abyssinica. Cyanus. Blue-bottle. The old Greek word for any dark-blue substance. Cyminum. Cumin. Same as cuminum. Cynoglossum. Hound's tongue. The classical name. From /crwv, dog, + •y/.uaca, tongue ; from the shape and texture of the leaves. Cyperus. Galingale. From Gr. Kvrreipoc, a marsh plant. Cypripedium. Lady's slipper. From Gr. Kvirpi$, Venus, -f- ireAthov, sandal. Cytisus. Broom. An ancient classical name for a shrubby kind of clover, perhaps Medicago arborea. Damascenus-a-um. Pertaining to Damascus. Daphne. Mezereum. Ancient Greek name of the bay-tree ; from the nymph, whom Apollo transformed into a laurel. Datura. Jimson weed. Thorn apple. Name derived from Sans, dhattura, Arab, tatura, tatula, the native name. Daucus. Carrot. The ancient Greek name. Decandrus-a-um. Having ten stamens. From Gr. dew, ten, -f- avrjp, ai'Apoc, man. Delphinium. Larkspur. Ancient Greek name, from fo/^/f (^eA^/v), dolphin, in allusion to the shape of the flower. Dentatus-a-um. • Dentated, toothed. Lat. dens, tooth. Desmodium. Tick Trefoil. From Gr. Jfoy/df , a bond or chain ; from the connected joints of the pods. Dianthus, Pink. Carnation. From Gr. A/dc, 01 Jupiter, + aytfof, flower. Dicentra. From Gr. /cdc, glaucous. From the glau- cous foliage. Globulus. Latin diminutive of globus; a little ball, globular ; referring to the button-like form of the fruit. Glutinosus-a-um. Glutinous, viscous ; referring to the resinous leaves and stems. From Lat. gluten, glue. Glycyrrhiza. Liquorice. From Gr. -ylvtcvc, sweet, + p/Ca, root ; referring to the taste of the root. Gnaphalium. Cudweed. Everlasting. Ancient Greek name of a downy plant. Probably allied with KvaQaMov, a lock of wool. Gossypium. Cotton. From Lat. gossypion, the cotton-tree. BOTANICAL NOMENCLATURE. 447 Gouania. Chew-stick. Gramineae. Grass family. From Lat. gramcn, grass. Granatum. Pomegranate. The ancient Latin name. Gratiola. Hedge hyssop. From Lat. gratia, favor ; because of its supposed medicinal virtue. Graveolens. Strong-smelling. Lat. gravis, strong, + olco, to emit a smell. Grindelia. Gum-plant. Tar-weed. Named for Prof. D. H. Grindel, a Russian botanist, who died in 1836. Guaiacum. Guaiac. From Span, guayaco, the native Haytian name of the plant. Guarana. Portuguese name formed from the native Brazilian name. Gummifer-a-um. Gum-producing. From Lat. gummi, gum, -f- fcro, to bear. Guttif er-a-um. Gum-exuding. From Lat. gutta, a drop, + fcro, to bear. • Gymnocladus. Kentucky coffee-tree. From Gr. •yvfiv6^) naked, -)- «/o(Jof, a branch, the branches being for long periods destitute of spray. Gypsophila. From Gr. -yv^t chalk, gypsum, + ^Aew, to love. Habenaria. Fringed orchis. From Latin habcna, a thong or rein. Hsematoxylon. From Gr. ai/uat blood, -f- gvhov, wood ; relating to the color of the heart wood. Hagenia. Cusso. Named after Dr. K. G. Hagen, German physician and apothecary (1749-1829). Hamamelis. Witch-hazel. Ancient Greek name of a tree with fruit like a pear (^jyAt'f). Of doubtful application, as the fruit is a woody capsule. Hanburii. Latinized genitive from Hanbury, an eminent English pharma- cognosist and traveller. Hedeoma. Pennyroyal. From Gr. jj6voop>s, mint. From ?/<%, sweet. + bafif/} scent. Hedera. Ivy. The classical Latin name. Helenium. Sneeze-weed. Ancient Greek name of a plant, said to be named after Helenus, son of Priam. Helianthemum. Rockrose. From Gr. q/.ioc, the sun, -f- avtitpov, flower. The large flowers open only once, in sunshine. Helianthus. Sunflower. From Gr. ^/t/oc, the sun, + arttoc, a flower. Heliotropium. Heliotrope. Turnsole. The ancient Greek name. From ^A/oc, the sun, -|- rpo-rr^ a turn ; alluding to the flowering at the summer solstice. Helleborus. Hellebore. The ancient classical name. Hepatica. Liver-leaf. From Gr. rj-rrariKo^^ belonging to the liver. The leaves were thought to resemble the liver in shape. Herbaceus-a-um. Herbaceous, grassy. From Lat. hcrba, grass, herbage. Hesperis. Rocket. Greek name for evening flower. From ia-ti>a, even- ing; alluding to the evening fragrance. Heuchera. Alum root. Named for Prof. J. H. Heucher, who died in 1747. Hevea. Brazilian rubber tree. From vernacular name hcve. 448 A TEXT-BOOK OF BOTANY. Hibiscus. Rose mallow. The ancient classical name. Hierochloe. Holy grass. From Gr. iepoc, sacred, -f- ^/o//, grass. Sweet- scented grasses strewn before church doors on saints' days. Hippocastanum. Horsechestnut. From Gr. ZTTTTOC, horse, + Kaarnvov^ chestnut. Hirsutus-a-um. Hirsute, rough, hairy. Hispidus-a-um. Rough, shaggy, bristly. Hordeum. Barley. The ancient Latin name. Houstonia. Bluets. Named for Dr, William Houston, an English botanist. Humulus. Hop. Name of uncertain origin. Perhaps from Lat. humus, ground, alluding to the fact that the plant creeps on the ground unless supported. Hydrangea. From Gr. vdup, water, + ayyelov, a vessel ; from the shape of the capsule. Hydrastis. Golden seal. Orange root. From Gr. iof, a rule; refer- ring to the quinary order of the flower. Pepo. Pumpkin. Melon. The ancient Latin word. Pereine. Of Pereira. Named in honor of Jonathan Pereira, an Eng- lish pharmacologist, who visited South America (1804-1853). Perfoliutus-a-um. Perfoliate. Stem apparently passing through the leaves. Lat. per, through, + folium, leaf. BOTANICAL NOMENCLATURE. 455 Perforatus-a-um. Perforate, having holes as if pricked through. Lat. perforo, to pierce through. Persea. Avocado. Ancient name of an Egyptian tree with fruit growing on the stem. Persicaria. Lady's thumb. From Lat. persicus, a peach tree. Petroselinum. Parsley. An ancient Greek plant-name. From Tm-pa, a rock, + cfkivov^ parsley. Phaseolus. Kidney bean. The ancient classical name. Philadelphus. Mock orange or Syringa. Ancient Greek name of a sweet flowering shrub ; applied by Linnaeus to this genus. Phillipinensis-e. Belonging to the Philippine Islands. Phlox. Greek name of a plant with flame-colored flowers. From <^/.d£ a flame. Physostigma. Calabar bean. From Gr. Qvaa, a bladder, + OT/;//«, a mark, stigma. Phytolacca. Pokeweed. From Gr. QVTOV, plant, + Ital. lacca, lake color ; alluding to the coloring matter which the berries yield. Picea. Spruce. The classical Latin name of the pitch-pine. Picrasma. Quassia. From Gr. TriKpaajuoc, bitterness. Picrotoxinum. From Gr. Trv/c/jog, bitter, + rot-mor, poison. Pilocarpus. Jaborandi. From Gr. vrZAof, a hair, -f- na/)7r6r} fruit ; refer- ring to the shape of the fruit. Pimenta. Allspice. From Spanish pimicnta, allspice. Derived from Latin pigmentum, spice. Pimpinella. Pimpernel. Said to be formed from Lat. bipinnula, equiva- lent to bipennis, two-winged; referring to the bipinnate leaves. Pinus. Pine. The ancient Latin name. Probably akin to pinna, a feather. Piper. Pepper. The classical Latin name. Piperitus-a-um. Peppery, pungent. Lat. piper, pepper. Pipsissewa. Chimaphila. An American Indian name. Piscipula. From Lat. piscis, fish. Pistacia. Pistachio. The ancient classical name. Planifolius-a-um. Having flat leaves. Lat. planns, flat, plane, + folium, leaf. Plantago. Plantain. The ancient Latin name. Podophyllum. Mandrake. From Greek TTO/T, loot, + yi/'/»r; referring to the foot-like leaves. Podostemon. Riverweed. From Gr. novq, foot, + or/^wr, thread, stamen ; the two stamens being apparently raised on a stalk by the side of the ovary. Polemonium. Greek valerian. An ancient Greek name of a plant. From war. Polygala. Milkwort. From Gr. nokvyakov, the ancient name, much, + 7'a?rz, milk. 456 A TEXT-BOOK OF BOTANY. Polygamus-a-um. Having some perfect flowers and others with stamens only, or pistils only, on the same plant ; polygamous. From Gr. Tro/.i-f much, -f- yafj.£uy to marry. Polygonatum. Solomon's seal. Ancient Greek name of a plant. From Tro/U'f, much, many, 4- y6wy yovaror^ knee; having many joints. Polygonum. Knotweed. The ancient classical name. From Gr. -rto/.bc much, many, + yovv, knee; having many knots or joints. Polypodium. Polypody. The ancient Greek name. From KOAVC, much, many, -f- irovc, , foot; alluding to the branching rootstock. Polyporus. Agaric. From Gr. no/.i^, many, + T(fy>of, a pore ; referring to the porous texture of the plant. Populus. Poplar. Aspen. The classical Latin name. Potentilla. Cinquefoil. Five-finger. Name is a diminutive form of Lat. potens, powerful ; from the reputed medicinal powers of one of the species. Pratensis-e. Growing in meadow-land. Lat. pratum, meadow. Precatorius-a-um. Imploring, beseeching. From Lat. prccor, to pray ; in allusion to the use of the seeds as beads in rosaries. Primula. Primrose. Cowslip. The name is a diminutive of Lat. primus, first; from the flowering of the primrose in early spring. Procumbens. Lying on the ground. From Lat. procumbo, to incline for- ward. Prunifolius-a-um. Having leaves resembling those of the plum tree. From Lat. prunus, plum tree, -f- folium, leaf. Prunum. Plum. Classical Latin name for the fruit. Prunus. Plum, cherry. Classical Latin name for the plum tree. Pruriens. Itching. From Lat. prurio, to itch ; in reference to the hairs, which occasion an intolerable itching. Psyllium. Flea-seed. Ancient Greek name for fleawort. Psoralea. From Gr. ^wpaAtof, scurfy; in reference to the glandular dots on the calyx and pods. Ptelea. Hop-tree. Ancient Greek name for the elm. Pteris. Brake or Bracken. Ancient Greek name for a kind of fern. From 7r-fpoi>, a wing; alluding to the pinnate or feathery fronds. Pterocarpus. From Gr. irrepov, a wing, -f napirog^ fruit ; in allusion to the winged legumes. Puber-a-um. Downy. Pubescens. Downy, hairy, woolly. From Lat. pubesco, to become downy. Pulegioides. Like fleabane. From Lat. pulegiiim (Gr. ^uXA/ov), fleabane, -f- -o-eidrjs, resembling ; in allusion to the appearance and odor. Pulicaria. Fleawort. The ancient Latin name. Pulmonaria. Lungwort. From Lat. pulmonarius, beneficial to the lungs. From its supposed curative properties. Pulsatilla. Pasque flower. From Lat. pulso, to strike, agitate ; of uncertain application. BOTANICAL NOMENCLATURE. 457 Punica. Pomegranate. From Lat. punicum, pomegranate tree. Purpureus-a-um. Purple-colored. Purshianus-a-um. Adjective formed from Purshia. Named for Fred. Pursh, a German botanist and author of Flora America: Scptcntrionalis. Pyrethrum. Pellitory. Feverfew. Ancient Greek name for a hot, spicy plant. Pyrus. Pear, Apple. Ancient Latin name for the pear tree. Quassia. Named for a negro, Quassy or Quash, who prescribed this remedy as a specific. Quebracho-bianco. From Sp. quebrantar, to break, -f- hacha, an axe; in allusion to the hard and tough bark. Blanco, white. Quercus. Oak. The classical Latin name. Quillaja. Soap bark. From vernacular quillai, Chili. Racemosus-a-um. Having racemes or clusters. Radicans. Rooting. From Lat. radico, to take root ; alluding to the fact that the stems send out roots. Ranunculus. Crowfoot. Buttercup. The Latin name for a little frog; some species being aquatic. Raphanus. Radish. The classical name. From Gr. pa, quickly, + (paivopat, to appear ; alluding to the rapid germination. Repens. Creeping. From Lat. rcpo, to creep. Reptans. Creeping. From Lat. repto, to creep. Reseda. Mignonette. From Lat. resedo, to calm, heal ; from its supposed sedative properties. Reticulatus-a-um. Reticulate, net-like. Lat. retia, a net; leaf -veins form- ing a net-work. Rhamnus. Buckthorn. The ancient classical name. Rhaponticus-a-um. Rhapontic. From Lat Rha, the Volga river, -f- ponticus, pertaining to the Pontic or Black Sea. The rhubarb growing on the banks of the Rha. Rheum. Rhubarb. From Lat. Rha, the river Volga, on whose banks the plant grew. Rhododendron. Rose-bay. The ancient name. From Gr. p66or, a rose, + div6pov, a tree. Rhus. Sumach. The ancient classical name. Ribes. Currant. Gooseberry. From Arabic ribas, a plant with an acid juice. Ricinus. Castor bean. The ancient Latin name. Robinia. Locust. Named for John and Vespasian Robin, royal gardeners of Paris, seventeenth century. Robustus-a-um. Robust, strong, oaken. Lat. robur, oak. Rosa. Rose. The ancient Latin name. Roseus-a-um. Rose-colored, rosy. Lat. rosa, a rose. Rosmarinus. Rosemary. From Lat. ros, dew, + niarinus, belonging to the sea ; from its maritime habitat. 458 A TEXT-BOOK OF BOTANY. Rostratus-a-um. Beaked, curved, rostrate. Lat. rostrum, a beak. Rotundifolius-a-um. Having round leaves. Latin rotundus, round, -f- folium, leaf. Ruber-ra-rum. Red, ruddy. Rubus. Bramble. Blackberry. Ancient Latin name, akin to ruber, red. Rugosus-a-um. Wrinkled, creased. Lat. ruga, a wrinkle. Rumex. Dock Sorrel. The classical Latin name. Ruta. Rue. The ancient classical name. Sabadilla. Cevadilla. From Span, cevadilla. Probably from Lat. cibus, food, though the seeds are poisonous. Sabal. Palmetto. From vernacular, Mexico or South America. Sabina. From Lat. Sabinus, of the Sabines ; a people of Italy who used the juniper as an incense. Saccharum. The classical name for sugar. Saigonicus-a-um. Of Saigon, a city and province in southern Annam. Salix. Willow. The classical Latin name. Salvia. Sage. The ancient Latin name. From salvo, to save ; because of its supposed healing qualities. Sambucus. Elder. The old Latin name, perhaps from Gr. aa/u.ii'k//^ a musir cal instrument. Sanctus-a-um. Holy, sacred, consecrated. Sanguinaria. Bloodroot. From Lat. sangninarius, bloody; from the color of the juice. Sanicula. Black snakeroot. Sanicle. From Lat. sano, to heal. Santalinus-a-um. Of the sandal-tree, of sandal- wood. Gr. adrraZov the > sandal-tree. Santalum. Sandal-wood. The ancient Greek name for sandal-tree. Saponaria. Soapwort. From Lat. sapo, soap; the juice forming a lather with water. Sarracenia. Pitcher plant. Named for Dr. Michel Sarrasin, of Quebec. Sassafras. The Spanish name. Probably a modification of saxifrage. Sativus-a-um. Cultivated. Propagated by seed. Scammonia. Scammony. Classical name of a plant. Scandens. Climbing. Lat. scando, to climb. Scilla. Squill. The ancient Greek name for the medicinal squill. Scirpus. Rush. The ancient Latin name. Scolopendrium. Adder's tongue. The ancient Greek name. From GKti'/6-tv'\;at the centipede; alluding to the sori. Scoparia. Broom-weed. l;n»m Lat scopa, a broom. Scutellaria. Skullcap. From Lat. scntclla, a dish; alluding to the calyx. Secale. Rye-. Latin name for a kind of grain. From scco, to cut. Sedum. Stonecrop. Orpine. Latin name of a houseleek. From scdco, to sit; alluding to the manner in which the plants attach themselves to walls and rocks. Semecarpus. Cashew-nut. From Gr. ai/ija, a mark, + Kdp-ut;, fruit. BOTANICAL NOMENCLATURE. 459 Sempervirens. Evergreen. Lat semper, always, -f- vireo, to be green. Senecio. Groundsel. Ragwort. Squaw-weed. From Lat. scnc.v, old man ; alluding to the hoariness of some species. Senega. Seneca root. From the Seneca tribe, North American Indians, who used it as a remedy for snake bites. Senegal. Name of a country and river in W. Africa. Habitat of the plant Acacia Senegal. Senna. Senna leaves. Name derived from Arabic Sana or sena. Serenoa. Saw palmetto. Named for Prof. Sereno Watson of Harvard University (1826-1892). Serotinus-a-um. Late, backward ; relating to the flowers and fruit. Serpentaria. Snakeroot. The ancient Latin name. From scrpens, a serpent. Serrulatus-a-um. Serrulate, notched. From Lat. serrula, a saw Sesamum. Sesame. The classical name of the sesame. Siliqua. The classical Latin name for a pod. Silphium. Rosin weed. Ancient Greek name of some resinous plant. Simaba. Cedron. From vernacular name, Guiana. Sinapis. Mustard. The ancient Greek name was oivain. The Latin had both forms, sinapis and sinapi. Sinensis-e. More commonly Chinensis. Pertaining to China. Sisymbrium. Hedge mustard. The ancient Greek name of a sweet-scented plant. Smilax. Green brier, cat brier. An ancient Greek name for the yew, and for several plants. Socotrinus-a-um. Of Socotra,, an island east of Africa. Solanum. Nightshade The ancient Latin name. Solidago. Goldenrod. From Lat. solido, to make whole, to heal; in refer- ence to its supposed healing properties. Somnifer-a-um. Sleep-producing. From Lat. soninus, sleep, -)- fero, to bear, bring. Sorbilis-e. Sorbile, fit to be drunk or sipped. Lat. sorbeo, to suck. Sorbus. Mountain ash. The ancient Latin name. Sorghum. Derivation uncertain. Probably of Chinese or East Indian origin. Spicatus-a-um. Supplied with spikes, spicate. Spigelia. Pink root. Worm-grass. Named for Adrian von der Spiegel, Flemish botanist of the seventeenth century. Spiraea. Hardback. Meadow-sweet. The ancient Greek name. From a-el(>a, a coil or twist ; from the twisting of the pods in some species. Squarrosus-a-um. Scabby, scurfy, ragged. Staphisagria. Stavesacre. From Gr. araoic, raisin, -f- aypio?, wild ; the fruit clusters resemble wild grapes. Stillingia. Named for Dr. B. Stillingfleet, English botanist of the eighteenth century. 460 A TEXT-BOOK OF BOTANY. Stramonium. Stinkweed. From French stramoine. Striatus-a-um. Marked with lines or ridges, striate ; Lat. strio, to groove, mark. Strophanthus. From Gr. ^arpoo^ a turn, twist, + d^oc, a flower ; from the twisted and tailed lobes of the corolla. Strychnos. The ancient Greek name of a poisonous plant. Styraciflua. A tree producing storax. From Lat. styrax, storax, + fluo, to flow. Styrax. Storax. The ancient Greek name of the storax tree. Succirubra. From Lat. succus, juice, -f- ruber, red; — the sap becomes red on exposure. Swertia. Chiretta. Named for Emanuel Sweert, herbalist of the seven- teenth century. Sylvaticus-a-um. )-,-,.. ,, T •, A £ v Pertaining to the woods. Lat. silva, a wood, forest. Sylvestns-e. ) Symphoricarpos. Snowberry. From Gr. av/LHpopeu, to bring together, + /ca/j-dc, fruit ; from the clustered berries. Symphytum. Comfrey. The ancient Greek name. From avfiqvu, to cause to grow together ; because of its reputed healing virtues. Syringa. Lilac. From Gr. avptyt-, a pipe ; in reference to the tubular corolla, or to the use of the wood for pipe-stems. Tabacum. Tobacco. Span, tabaco, from the Indian word denoting the tube or pipe used in smoking the plant. Tamarindus. Indian date. From Arabic tamarhindi, tamar, a dried date, -f- Hind, India. Tanacetum. Tansy. From the French name, tanaisie, derived from Gr. afld^aroc, immortal. Taraxacum. Dandelion. From rapdccu, to stir up, disorder ; in allusion to its medicinal properties. Terebinthina. Turpentine. From Gr. TtpffiivOoq, the turpentine tree. Teticrium. Germander. Named for Teucer, king of Troy. Thalictroides. Resembling thalictrum. From Gr. Hd/.iKTpov, -(- o-et6r/<;t like. Thalictrum. Meadow rue. Ancient Greek name of a plant. Thea. Tea. French The, from Chinese tsha. Theobroma. Cacao. From Gr. tf/o^ a god, -f- jSpwua, food. Thuja. Arbor Vita?, Cedar. Ancient Greek name for an African tree with sweet-smelling wood. Thymus. Thyme. Ancient Greek name. From 6'ru, to sacrifice ; alluding to the sweet odor. Tiarella. False mitrewort Coolwort. Diminutive of Lat. tiara, cap; from some fancied resemblance of the capsules. Tilia. Linden. Basswood. The classical Latin name. Tinctorius-a-um. Pertaining to dyeing, containing coloring matter. Lat. lingo, to dye, color. BOTANICAL NOMENCLATURE 461 Tinctorum. Of the dyers. Genitive plural of tinctor, a dyer. Toluifera. Balsam tree. Said to be formed from Tolu (Santiago de Tolu, in New Granada), whence balsam was first brought, + fcro, to bear. Tomentosus-a-um. Tomentose. Woolly. Lat. tomentum, stuffing. Toxicodendron. From Gr. rof/Kdr, poison, -\- 6tv6i><>v, tree ; poisonous shrubs. Tradescantia. Spiderwort. Named for John Tradescant, gardener to Charles I. Tragacantha. Tragacanth. The ancient Greek name for the Astragalus. From T/myoc, a goat, + d/cai^a, a thorn ; in allusion to the character of the gummy exudation. Tragopogon. Salsify. Goat's beard. Ancient Greek name of a plant. From rpayoq, a goat, -f- iruyuv, beard ; alluding to the pappus. Triandrus-a-um. Having three stamens. Gr. T/J^C, three, -f- av?'/pt man. Tricolor. Having three colors, tricolored. Lat. trcs, three, -f- color, color. Tricuspidatus-a-um. -Ending in three points. Lat. tricuspis, three-pointed. Trifolium. Clover. Trefoil. The ancient Latin name. Three-leafed. Trilisa. Vanilla-leaf. Deer's tongue. Name an anagram of Liatris. Trillium. Wake robin. Birthroot. From Lat. ires, three ; all the parts being in threes. Triphyllus-a-um. Having three leaves. Gr. rpel?, three, 0W.Aoi/, leaf. Triticum. Wheat. The ancient Latin name. From tritus, past participle of tero, threshed or ground. Trivialis-e. Common, trivial. Lat. tres, three, -\- via, road ; three roads, growing along many roads. Tsuga. Hemlock. The Japanese name of one of the species. Tuberosus-a-um. Tuberous. Lat. tuber, lump, tumor. Turpethum. Turpeth. From Persian tirbid, a cathartic ; iurbad, a purga- tive root. Tussilago. Coltsfoot. The ancient Latin name. From tussis, a cough, for which the plant is a reputed remedy. Ulmaria. Queen of the meadow. From uliinis, elm; hence elm-like. Ulmus. Elm. The classical Latin name. Umbellatus-a-um. Umbellated, like an umbel. Lat. umbclla, little shade, umbel. Umbellularia. Bay-laurel. From nmbcllula, little umbel, a late Latin diminutive of umbclla. Uniflorus-a-um. Bearing one flower only. Lat. iinns, one, + flos, flower. Urginea. Squill. Sea onion. From Lat. urgeo, to press ; alluding to its flattened seeds. Urtica. Nettle. The ancient Latin name. Usitatissimus-a-um. Most useful, common, familiar ; superlative degree of usitatus. Ustilago. Smut, Bunt. An ancient Latin name of a plant. Uva-ursi. Bearberry. From Latin iiva, a grape, 4- ursi, of a bear. 462 A TEXT-BOOK OF BOTANY. Valeriana. Valerian. Probably from Lat. valco, to be strong. Vanilla. From Spanish vainilla, diminutive of -vaina, a sheath, pod ; be- cause its seeds are contained in little pods. Variifolius-a-um. With varying leaves. Lat. varius, various, changing, -f- folinni, a leaf. Venenosus-a-um. Poisonous, deadly. Lat. vcnennm, poison. Veratrum. False hellebore. The classical Latin name. Veronica. Speedwell. Dedicated to St. Veronica. Versicolor. Having various colors. Lat. vcrfio, to turn, change, -f- color, color. Verticillatus-a-um. Disposed in a whorl. Lat. verticillus, diminutive of vertex, a whirl ; referring to the leaves or flowers. Verus-a-um. True, genuine, original. Viburnum. Black haw. Arrow-wood. The ancient Latin name. Victorialis. Ancient Latin name of a plant. Villosus-a-um. Hairy, shaggy, villous. Vinifer-a-um. Wine-producing. Lat. innum, wine, + fcro, to bear. Viola. Violet. Heart's ease. The ancient Latin name of the genus. Virginianus-a-um. ) . . ,r. . . J. Of or belonging to Virginia. Virgmicus-a-um. \ Viridiflorus-a-um. Having green flowers. Lat. viridis, green, + flos, a flower. Viridis-e. Green. Virosus-a-um. Having a bad odor, fetid. Lat. virus, an offensive smell. Vitis. Grape. The classical Latin name. Vouacapoua. Araroba tree. From vernacular name, Central America. Vulgaris-e. Common, general, ordinary. Wisteria. Named in honor of Prof. Caspar Wistar, distinguished anatomist of Philadelphia. Xanthium. Clotbur, Cocklebur. Greek name of some plant used to dye the hair. From t-avtidq,] yellow. Xanthoxylum. Prickly Ash. From Gr. favfldf, yellow, -f- ff-Aov, wood ; referring to the color of the roots. Zea. Maize. Indian corn. Ancient classical name for a kind of grain. Zeylonicus-a-um. Of or belonging to Ceylon. Zingiber. Ginger. The ancient Greek name. CHAPTER V CLASSIFICATION OF ANGIOSPERMS YIELDING ECONOMIC PRODUCTS IN this chapter will be given in natural sequence a list of the principal orders of plants that yield medicinal and other economical products. While great stress will be laid upon the plants used in medicine, yet considerable attention will also be given to the other economic substances furnished by the angiosperms, as food- products, fibers, coloring principles, woods, and timbers, as well as to the plants commonly cultivated for ornamental purposes. It will be found that the number of plants useful to man is a very large one, being derived from all the important families, so that in their consideration the student will gain a rather comprehensive view of the entire group. A. CLASS MONOCOTYLEDONE^E. The Monocotyledons are mainly distinguished as follows : The embryo has only one cotyledon ; the leaves are mostly scattered and parallel-veined ; the fibrovascular bundles of the stem are of the closed type, and the flowers are typically trimerous. I. ORDER PANDANALES. This order includes members which are aquatic or marsh plants, with narrow, elongated leaves and very small, imperfect and incomplete flowers in spikes or heads. The TYPHACE^E or Cat-tail family has the flowyers borne in densely crowded terminal spikes, the staminate flowers being at the upper end of the spike, while the pistillate flowers which are beneath are more persistent. The SPARGANIACE^E or Bur-reed family have the flowers borne in densely globose heads, the staminate heads being rather small and near the upper part of the stalk, while the pistillate heads are larger and situated a short distance below the staminate ones (Fig. 252). 463 464 A TEXT-BOOK OF BOTANY. FIG. 252. Bur-reed (Sparganium eurycarpiim), a perennial plant flowering throughout the summer and growing on the borders of ponds, lakes, and rivers throughout the United States. It grows to a height of 8 to 12 dm., and produces long, ribbon-like leaves. The flowers are in heads, becoming bur-like from the divergent beaks. — After Brown. CLASSIFICATION OF ANGTOSPERMS. 46; FlG. 253. Arrow-head (Sagittaria latifolia), a common marsh or aquatic plant and very widely distributed. The leaves are variable, but almost always sagittate. It produces naked scapes which are sheathed by the bases of the petioles; the white flowers are produced all summer. — After Troth. 30 466 A TEXT-BOOK OF BOTANY. IT. ORDER NAIADALES. This order, as with other rather primitive orders, is made up mostly of aquatic and marsh plants, the flowers frequently being spicated. The NAIADACE;E or Pond-weed family comprises such genera as Potamogeton, the common Pond-weed, and Zostera, or Eel- grass, which is extremely common in bays and estuaries in all parts of the country, and in many places its collection forms an active industry. It is used in upholstery work and as a packing material. To the ALISMACE^: or Water-Plantain family belong Alisma, the Water- Plantain, and Sagittaria, or Arrow-head, which is a very attractive plant (Fig. 253) . Of the latter there are a large number of species which are widely distributed. III. ORDER GRAMINALES OR GLUMIFLOR^. This order is composed of the two families, grasses (Gram- inese) and sedges (Cyperacese). a. GRAMINE/E OR GRASS FAMILY.— The plants of this family are nearly all herbs having cylindric, generally hollow culms with swollen nodes. The leaves are exactly alternate, and have long sheaths which are split or seldom closed, tubular, and nearly always with a distinct ligule. The flowers are mostly hermaphrodite and borne in spikelets with alternate floral-leaves, the spikelets themselves being borne in spicate or paniculate in- florescences. Each spikelet (Figs. 255, 256) consists of two (seldom more) empty glumes, which are the lowest floral-leaves in each spikelet ; a varied number of flowering glumes, frequently awnecl or toothed, are situated inside the empty glumes, and each of which subtends a short branch (the rhachilla), the latter bearing an adorsed fore leaf (the pale), which is generally two- keeled and two-toothed, enclosing two minute scales (lodicules) and the flower. The flower has mostly three stamens (there being six stamens in Oryza and Bambusa), with the anthers versa- tile, and a simple gymecium consisting of one carpel having two styles and a plumose stigma. The ovary is unilocular with one ascending or pendulous ovule. The fruit is a grain or caryopsis, CLASSIFICATION OF ANGIOSPERMS. 467 the seed being always firmly united with the thin pericarp (except in Sporobolus, Eleusine, etc.). The embryo is situated at the base, on the outer convex surface of the seed, outside the endo- sperm. On germination the cotyledons remain in the seed. The endosperm contains numerous starch grains and oil, while the gluten layer around the endosperm contains proteins. The number of layers of gluten- or aleurone-containing cells varies in the different cereals. In corn, wheat, and rye it consists of but a single layer ; in oat (Fig. 247) and rice, of i or 2 layers ; while in barley it is made up of 2 to 4 layers. The Grasses comprise about 3500 species and are distributed in all parts of the world. While most of the plants are grass-like, B FIG. 254. Diagrams of cross-sections of monocotyledonous flowers: t, stem of plant; f, bract; s, sepals or outer circle of perianth; p, petals or inner circle of perianth; a, stamens; c, ovary. A, regular flower of the lily; B, irregular flower of iris. C, flower of an orchid, in which 1 is the position of the lip and S & of the two staminodes. — After Warming. still some of them, as the bamboos of the Tropics, become quite tall, having woody siliceous stems and bearing many branches in the axils of the leaves. The grasses yield the cereal grains forming so large a proportion of the food of man, and forage constituting the food of many of the lower animals. The following are some of the important cereals: Wheat (Triticinn sativum and its varie- ties), corn (Zea Mays), oat (Avena sativa), rice (Oryza sativa), barley (Hordeum sativum and its varieties), rye (Secale cereale). A number of the species yield a sweet cell-sap from which cane sugar is made, of which the most important are the sugar cane (Sacchannii officinarum) and sorghum (Andropogon arundina- ceus saccharatus and other varieties). (Consult pp. 148, 156, 198.) 468 A TEXT-BOOK OF BOTANY. A large number of the grasses are used in medicine, one of which, couch-grass (Agropyron repens), is official. Agropyron repens is a common perennial grass, forming slen- der jointed rhizomes, by means of which the plant is extensively propagated ; the culms vary from one to four feet in height, the spikelets are 3- to /-flowered ; and the empty glumes, 5- to 7-nerved, acute or with an awn-like apex. Hordeum sativum is an annual grass with the flowers in ter- FIG. 255. Wheat (Triticum): A, zigzag axis or rachis of ear showing the notches where the spikelets were inserted; B, an entire spikelet; C, a flower with the pales; D, a flower without the pales, showing the lodicules at the base; E, glume; F, outer pale; G. inner pale; H, fruit (caryopsis) ; I, longitudinal section of fruit. — After Warming. minal cylindrical spikes resembling wheat. The spikelets arc ses- sile, i-flowered, and usually in clusters of three on opposite sides of the notched rachis. The empty glumes are long and narrow, forming a kind of involucre around the spikelet. It is supposed that Hordeum sativuui is a cultivated form of H. spoutcDicmn growing in the countries between Asia Minor and other parts of Western and Southwestern Asia. Three important varieties are distinguished, depending upon the number of rows of grains in CLASSIFICATION OF ANGIOSPERMS. 469 the ear. H. sativum distichon includes the plants having 2-rowed ears, and these are chiefly grown in Middle Europe and England. H. sativum he.vasticJion includes the plants having the grains in 6 rows, these having been cultivated since prehistoric times and furnishes the winter barley. H. sat wit in vulgar r includes the plants in 'which the grains are in 6 irregular rows, and these are cultivated in northern temperate regions. The latter plant is cultivated in the United States and furnishes the spring or summer barley, largely used in the preparation of malt. Zea Mays (Indian Corn) is a cereal plant probably indigenous to Central Mexico. It is extensively cultivated in the United FIG 256. Diagrammatic outline of a spikelet: nY, lower glume; <£ Y, upper glume; nl, outer pale; $ I, inner pale; 1, 1, lodicules; st, stamens; I-I, main axis; II, lateral axes or branches. — After Warming. States and other parts of the world for its grain. From a multi- ple, primary, somewhat fibrous root arise one or more erect simple culms, which are grooved on alternate sides in the successive internodes and from the nodes of which arise aerial secondary roots. The leaves are alternate and consist of 3 parts: (a) a blade, which is long, broadly-linear and tapering toward the apex, the tip being pendulous; (b) a lower sheathing portion which is open; and (c) a short, translucent, somewhat hairy ligule, situated between the sheath and the blade. The flowers are monoecious, the staminate, which are arranged in a terminal pan- icle, maturing first ; the pistillate occur in axillary spikes, the axes of which constitute the corn cob. They are enclosed in- 4/o A TEXT-BOOK OF BOTANY. spathe-like bracts or husks, from which the long filiform styles (p. 178) protrude. The grain is somewhat ovate or triangular, flattened, pointed at the base, grooved on one side, indicating the position of the embryo, from 10 to 15 mm. long and about 10 mm. broad, more or less translucent, and varies in color in the different varieties. The constituents of the corn grain are 50 to 75 per cent, of starch ; about 10 per cent, of proteins ; 4.29 per cent, of a fixed oil; about 5 per cent, of sugar, and 1.29 per cent, of ash. There are a large number of varieties and sub-varieties of Zca Mays, some of the former being ranked as species. The follow- ing well-defined varieties may be mentioned : (1) Zea Mays evcrta, to which belong the POP-CORNS. The size of the ears and grains is about one-half or less that of the other corns ; the grains have a more or less translucent and horny endosperm, the cells of the latter containing numerous compactly arranged polygonal starch grains, which are from 7 to io/x in diameter and have a central rarefied area from 2 to 7 ^ in diam- eter. It is owing to the structure of the starch grains that the peculiar popping of the corn grains results when they are heated. Heating the corn grains at 145° to 160° C. for from 4 to 10 min- utes causes the bursting of the starch grains, and at the same time a rupture of the cells and splitting of the pericarp into 4 parts. The white appearance of the popped grains is due to the inclusion of air in the bursted cells. During the heating the starch is con- verted into a soluble form, and this gives popped corn its nutritive value. Some of the flint and dent corns show a similar tendency to pop when heated, but it is only in those parts of the endo- sperm that are horny and the cells of which contain compactly arranged polygonal starch grains in which the rarefied area is at least from one-tenth to one-fifth the diameter of the entire grain. o Pieces of the pop-corn, as well as the horny portions of some of the flint and dent corns, will pop as readily as the whole grains. (2) Zea Mays indcntata yields the DENT or FLINT CORNS, the grains of which have a corneous (horny) endosperm on the sides and are indented at the summit, owing to the shrinking of the cells which contain more cell-sap and less compactly arranged starch grains. The starch grains in the cells of the horny endosperm resem- CLASSIFICATION OF ANGIOSPERMS. .471 FIG. 257. Carex lurida, one of the Sedge family (Cyperacece), found throughout the summer in swamps and wet meadows in the eastern and central United States. It is a perennial grass-like herb with triangular culms, 3-ranked leaves, and with 2 to 4 spikes of flowers. The genus is a vast one of more than a thousand species, widely distributed and most abundant in the temperate zones. — After Troth. ble those of pop-corn, but the starch grains in the other cells are more or less rounded or slightly polygonal, and vary from 5 to 25 /* in diameter; the central rarefied area is either wanting or usually not more than 2 ^ in diameter. (3) Zea Mays saccharata yields the SUGAR CORNS. \Yhile the 472 A TEXT-BOOK OF BOTAXY. grains are more or less translucent and horny, they have a wrinkled or shrivelled surface. The cells of the endosperm con- tain gum-like substances and a relatively small number of nearly spherical starch grains from 4 to io/x in diameter. BROOM CORN (Andropogon arundinaceus vulgare) is a plant which is cultivated for the panicles or seed heads, which are used in the manufacture of brooms. This plant differs from the other species of Andropogon in that the branches of the panicles are longer, straighter, and stronger, forming a so-called " brush." Quite a number of the grasses contain odorous principles, as Andropogon citratus, which yields lemon-grass oil; A. Schccnan- thuSj which yields gingergrass or geranium-grass oil; A. squar- rosns, the rhizome of which is known as Vetiver. Coumarin is found in Vanilla grass (Anthoxanthum odoratiun) and white or Dutch clover (Hierochlcc odorata). Some species of Stipa are used in the manufacture of paper (Alfa or Esparto) in North Africa and Spain. b. CYPERACE^E OR SEDGE FAMILY.— These plants are all herbaceous, the majority being perennial (seldom annual). The rhizomes are mostly sympodial (being monopodial, however, in certain Carices), and the stems are mostly solid and triangular, without swollen nodes. The leaves are grass-like, generally arranged in three rows, and the sheath is closed, being mostly without ligules. The flowers may be hermaphrodite or unisexual, sometimes dioecious, and arranged in spikes or racemes. The perianth is wanting or only represented by 6 bristles, or by an indefinite number of ha'irs. The number of stamens is 3, with the anthers attached by their bases to the filament. The gynaecium consists of 2 to 3 carpels, with one style divided into 2 or 3 branches, and provided with papillre. The fruit is a nut, whose seed is generally united with the pericarp. The embryo is small and is centrally situated at the base of the seed, being surrounded by the endosperm. On germination, the cotyledon is freed from the seed. A number of the sedges yield food products, as the rhizomes of Cyperus cscnlcntus and Eleocharis tuber osa, the latter of which is used in the manufacture of starch in China and India. Quite n number of species of Scirpus, Cyperus, Carex, etc., are used in CLASSIFICATION OF AXGIOSPERMS. 473 medicine. Various species of Cyperus (C. scariosus, of the East Indies, and C. pertenuis, of India) yield ethereal oils and are used in making perfumery. Cyperus Papyrus is used in medicine and also furnished the paper of the Ancients. IV. ORDER PRINCIPES. In this order is included that interesting group of tropical and sub-tropical plants the PALMS (Palmar). They are arbores- cent, having simple unbranched trunks which are terminated by clusters of leaves, in the axils of which flowers are produced. The leaves are pinnate (Feather Palms) or palmate (Fan Palms) and often very large. The petiole is well developed, with an am- plexicaul, more or less fibrous sheath. The inflorescence is usually lateral, in some cases forming a large spadix with a woody, boat- shaped spathe. In comparison the individual flowers are very small. The fruit is either a berry, as in the Date palm, or a drupe, as in the Cocoa-nut palm, generally i -seeded and with a large horny or bony endosperm, as in the Date palm (p. 135) and Phytelephas macrocarpa, the latter of which yields vegetable ivory, used in the making of buttons (Fig. 258). The fruit of the saw palmetto [Serenoa (Sabal) serrulata], one of the fan palms, is official. The saw palmetto is characterized by having a creeping, branching root-stock or rhizome, one end of which rises a short distance above ground, this portion being surmounted by a dense crown of leaves. The petioles are slender and spinose on the edges ; the blade is fan-shaped and consists of a number of palmate divisions which are slightly cleft at the apex. The inflorescence is densely tomentose and shorter than the leaves. The fruit is a I -seeded drupe. The palms yield a number of useful products. The Betel-nut palm (Areca Catechu) produces a seed having medicinal proper- ties (Fig. 259). The seeds, known as ARECA NUT, are 20 to 25 mm. long, conical, grayish-brown, with numerous spiral, reddish veins, heavy, hard, somewhat aromatic, astringent, and slightly acrid. They contain about o.i per cent, of an oily liquid alkaloid, arecoline, which chemically and in its physiological action resem- bles pelletierine ; 14 per cent, of tannin, resembling catechutannic acid ; gallic acid ; a red coloring principle ; and 14 per cent, of a 474 A TEXT-BOOK OF BOTANY. fixed oil. They also contain 3 other alkaloids: arecaine, arecai- dine, and guvacine, but these do not seem to give the drug its properties. CARNAUBA-WAX is obtained from the Carnauba-palm of Brazil (Copernicia cerifera). The wax exudes from the surface of the young leaves and is obtained by boiling them with water. DRAGON'S FIG. 258. Vegetable Ivory, the endosperm of the seeds of a Central American palm (Phytelephas macrocarpa). The fruits are produced near the ground, are nearly globular, measuring about i meter in circumference, and weigh about 14 pounds each. They are covered with a woody spinose wall (A), and enclose a number of drupes (B), each of which contains a single hard seed (C). The latter contains a hard, white, fine-grained endosperm (D); it is used in making small articles of turnery, as buttons, etc. — Reproduced by permis- sion of The Philadelphia Commercial Museum. , a bright red resinous substance, is obtained from the juice of the fleshy fruit of Calamus Draco. It consists chiefly of resin, some tannin, and about 3 per cent, of benzoic acid. The Oil palm (Elccis guinecnsis) of equatorial West Africa yields a drupe with an oily sarcocarp, from which, by means of pressure or boiling with water, PALM OIL is obtained. The Cocoa- nut palm (Cocos nucifera) yields the COCOA NUT of the market, CLASSIFICATION OF AXGIOSPERMS. 475 and is probably one of the most useful palms to the natives, fur- nishing, as it does, food, clothing, utensils of all kinds, building materials, etc. The Sago-palms (Metroxylon Rumphii and M. Iccvc) yield SAGO, which is prepared by washing out the starch from the cut stems and subsequently heating it. A tree 15 years old yields from three to four hundred kilograms of sago starch. The Date palm (P/jamr dactylifera) yields the DATES of the FIG. 259. A number of Areca-nut palms (Areca Catechu) growing in Ceylon. The stems are slender, attaining a height of 25 meters or more, with a diameter of 3 to 4 dm. and bearing a cluster of leaves at the summit. The palm is also known as the Betel-nut palm, and is extensively cultivated throughout tropical India. — Reproduced by permission of The Philadelphia Commercial Museum. market, and it is interesting to note that since very early times the fruits produced by the growers in the Orient have been the result of artificial or hand-pollination. V. ORDER ARALES OR SPATHIFLOR.-E. This order includes two families which are markedly different in their habits : ( I ) The Aracese, which are rather large herbs with an inflorescence known a's a spadix and consisting of a fleshy 476 A TEXT-BOOK OF BOTANY. FIG. 260. Fruits and rlowers of several of the palms. A, cluster of flowering spikes of the cocoanut palm (Cocos nucifera); B, number of the young fruits of the cocoanut palm; C, cluster of the ovoid fruits of the betel-nut palm (Areca Catechu); D, compound inflorescence of drooping spikes of the kittul (kittool) palm (Caryota urens}; E, large clusters of deltoid fruits of kittul palm. — Reproduced by permission of the Philadelphia Commercial Museum. The cocoanut palm yields a larger number of economic products than any other tree in the world; the fruit is edible and yields the cocoanut oil, the sap produces an alcoholic beverage, the leaves are used for making useful articles, and the wood is employed in cabinet making. The Betel-nut palm yields a number of valuable products, the most important being the seed, which is not only used to stimulate digestion, but is used in many religious cere- monies, as well as in regulating the intercourse of the more polished classes of the East. The base of the leaf stalks of the kittul palm yield a fiber which is elastic, shows considerable tenacity, and is used in the making of brushes for brewers' ustt. CLASSIFICATION OF ANGIOSPERMS. 477 FIG. 261. Jack-in-the-Pulpit, or Indian Turnip (Ariscema triphyllum), a very common perennial herb growing in woods and thickets of the eastern and central parts of the United States and Canada, and characterized by i or 2 leaves which are divided into 3 elliptical- ovate, pointed leaflets and a characteristic spathe of a greenish color, frequently purple- striped and curving in a broad flap over the top of the club-shaped spadix. The plant produces a turnip-shaped corm with an intensely acrid juice. — After Tvoth. 478 A TEXT-BOOK OF BOTANY. spike, which is subtended or enclosed by a large bract known as a spathe, as in the Calla-lily, where it is large and white, and (2) the Lemnaceae or duckweed family, which is composed of minute, FlG. 262. Skunk Cabbage (Symplocarpus fcttidus), a perennial herb producing a very thick rhizome, from which arise in the early spring the flowers crowded on a spadix sur- rounded by a large, shell-like spathe which barely rises out of the ground and is striped or spotted with purple and yellowish-green. These are followed by a cluster of ovate, cordate leaves becoming 3 to 6 dm. long. In the illustration are shown 4 of the spathes, the one at the left being cut open to show the globular or ovoid spadix, and a single leaf unfolding. — After Troth. floating, thalloid plants that develop one or more flowers on the margin or upper surface of the thallus. ARACE^ OR ARUM FAMILY.— The plants belonging to this family are perennial herbs with tuberous or fleshy rhizomes CLASSIFICATION OF ANGIOSPERMS. 479 and simple or compound leaves which are usually long-petioled. The spadix is densely flowered, the staminate flowers being above and the pistillate below on the same axis, or the plants are wholly dioecious. The perianth when present consists of 4 to 6 scale-like segments. Frequently the spadix is subtended or enclosed by a more or less showy spathe. The fruit is usually a berry, some- times a utricle. FIG. 263. Water Arum (Calla palustris}, showing portion of rhizome, the broadly ovate and cordate leaves, and the inflorescence, which consists of a cylindrical spadix and an elliptical spreading spathe. A number of the plants of this family have medicinal proper- ties, and one of them yields the unofficial drug CALAMUS. The drug is derived from sweet flag (Acorns Calamus), a plant common in swamps and along streams in the Eastern United States, and characterized by its long, narrow, linear, bilateral leaves, which are from 6 to 18 dm. in height and about 25 mm. in width. The inflorescence is a spike-like spadix having greenish-yellow flowers. Many of the Araceae possess an acrid juice. The acridity is 48o A TEXT-BOOK OF BOTANY. probably due either to saponin or an acrid volatile principle rather than to raphides of calcium oxalate. Frequently these principles are dissipated or destroyed on cooking, and the plants are then used as food, as the WATER ARUM (Calla palustris), which on account of its acrid principles is used as a remedy for snake bites when in the fresh condition, but which on drying loses its acridity and being rich in starch is used as a food (Fig. 263). To this family also belong Jack-in-the-pulpit, or INDIAN TURNIP (Ari- sccma triphyllum), the acrid corm of which is used in medicine (Fig. 261) ; SKUNK CABBAGE (Syuiplocarpus fcctidus), the fetid rhizome of which has medicinal properties (Fig. 262). A number of plants of the Arum family are rich in starch, as the tubers of Xanthosoma edule of Surinam, which contain 62 per cent, of starch. VI. ORDER XYRIDEALES OR FARINOSyE. The plants are mostly perennial herbs of tropical and sub- tropical America. The order includes a number of families, among which is BROMELIACE.E, to which the pineapple (Ananas sativus) belongs. PINEAPPLE is a native of Brazil and is now cul- tivated in warm countries of the eastern and western hemispheres. The fruit contains a proteolytic enzyme resembling trypsin and also a milk-curdling ferment. The bast fibers of the leaves are used for textile purposes. Some of the Bromeliacese are epi- phytic (air-plants), the best known member being probably the FLORIDA MOSS (Tillandsia usneoides), which is used in upholstery (Fig. 264). The family Commelinacese is represented in the United States by Commelina or day-flower, some species of which have medic- inal properties. The roots of some tropical species contain saponin, as C. dcficicns, of Brazil. The rhizomes of a number of species of Commehfia Contain notable quantities of starch and are edible. The spiderworts (Tradescantia) common in rich soil in the United States, and the Wandering Jew (Tradescantia Zebrina] commonly cultivated as an ornamental plant, also belong to this family. To the PONTEDERIACE.E belong several perennial aquatic or bog plants, whose leaves are usually thick or in some cases long and grass-like. The flowers are frequently arranged in Spikes subtended by leaf-like spathes (Fig. 265). CLASSIFICATION OF ANGIOSPERMS. 481 j03 ^33 |S| • ™ "H. 482 A TEXT-BOOK OF BOTANY. FIG. 265. Pickerel vv eeu (Pontederia cordata), a common aquatic herb growing along the margin of slow streams. It is a very hardy plant occurring far north and grows best in water ten or twelve inches deep. It produces long-petioled leaves and a single stem bearing a spike of violet-blue, ephemeral flowers. — After Troth. CLASSIFICATION OF ANGIOSPERMS. 483 FIG. 266. Small Solomon's Seal, also commonly known as true Solomon's Seal (Poly- gonalum biflorum). It is a perennial herb with lance-oblong, sessile leaves, in the axils of which are usually two nodding greenish flowers. The plant grows in moist woods or wooded hillsides, and receives its common name from the creeping knotted rhizomes, on the upper surface of which are usually one or more prominent circular scars, formed upon the decay of the aerial shoots. — After Blown. 4^4 A TEXT-BOOK OF BOTANY - '-•• ( A FIG. 267. False Solomon's Seal or False Spikenard (Smilacina racemosa}, a perennial herb with a somewhat stout stem, a number of alternate. parallel-veined leaves and a terminal raceme of whitish, sometimes fragrant, flowers. It forms a horizontal knotted rhizome, on the upper surface of which are found circular scars. It may be found growing in under- brush in moist woods. — After Brown. CLASSIFICATION OF AXGIOSPERMS. 485 VII. ORDER LILIALES OR LILIIFLOR.^. The plants of this order are mostly perennial herbs with rhi- zomes, tubers, bulbs, or fibrous roots. The leaves are parallel- veined. a. LILIACE^ OR LILY FAMILY.— The plants are the most typical of the Monocotyledons. They are scape-like herbs with bulbs ; the flowers are symmetrical, and the perianth is parted into 6 more or less distinct segments (Fig. 123) ; the anthers are introrse. The ovary is free, 3-locular, with a single style, and the fruit is a 3-locular, loculicidally dehiscent capsule. The Liliaceae is one of the most important families, containing about 2500 species, many of which are of great economic interest. Quite a number are cultivated on account of the beauty and fra- grance of their flowers. Among the latter are the hyacinth, lily, lily-of -the- valley, tuberose, tulip, and yucca. Of those yielding food products we have asparagus, being the young shoots of Asparagus officinalis. The edible bulbs. include the onion (Alliiun Cepa), garlic (Allium sativum), the leek or scullion (Allinm Porrum), and chives (Allium Schcenoprasum). A number of the Liliacese are among the common wild flowers, as swamp pink (Fig. 272), bell wort (Uvularia), lily (Lilium), dog's-tooth violet (Erythronium), Star of Bethlehem (Ornithogalum), False Solo- mon's Seal (Fig. 267), True Solomon's Seal (Fig. 266), Indian Cucumber- root (Medeola), colic-root (Fig. 271), cat brier (Smilax), etc. The following plants are of medicinal interest: Veratrum viride is a plant 2 to 8 feet high, which is charac- terized by the broad, clasping, strongly plicate leaves, and by hav- ing the flowers in large terminal panicles (Fig. 268). The plant1 is found in swamps and wet woods in the United States in spring and early summer. The rhizome is upright, and it with the roots is used in medicine. The plant, including the rhizome, closely resembles the Veratrum album of Europe. Colchicnm autumnale--This is the autumnal-flowering colchi- pum, a perennial herb but a few inches high which arises from a corm and bears proportionately large lilac-colored flowers. The fruit consists of 3 follicles containing numerous seeds. The corm and seeds of this and other species of Colchicum are used in 486 A TEXT-BOOK OF BOTANY. FIG. 268. Flowering specimen of Vcratrum viride, showing the spreading, spike-like racemes and the parallel-veined leaves. CLASSIFICATION OF AXGIOSPERMS. 487 medicine. Among the species yielding large corms and extensively cultivated is Colchicum Burmanii (Fig. 269). Aloe species.- -The stems are about a meter high and bear at the summit a cluster of thick, succulent leaves which are lance- olate and spinous-toothed (Fig. 270). The inflorescences are in long spikes which are quite showy and characteristic for the differ- ent species. Aloe Pcrryi, which yields the SOCOTRINE ALOES, possesses leaves with white spines and flowers that are orange-red or scarlet at the base, the stamens being unequal ; Aloe vera, which yields the BARBADOES or CURACAO ALOES, has leaves with yellow or reddish spines and yellow flowers in which the stamens are as long as the corolla ; Aloe ferox and some other African species, which yield CAPE and UGANDA ALOES, have flowers in close spikes, the petals being white and marked by green lines, and the stamens much longer than the corolla. The inspissated juice is official in all the pharmacopoeias. Urginca maritima, which yields the drug squill, is character- ized by its large, onion-like bulb, from which arise ten to twenty broadly lanceolate, grayish-green leaves ; and by having the in- florescence in long spikes consisting of whitish flowers which have a distinctly purple stripe on each division of the perianth. Conz'allaria majalis or Lily-of-the-valley is a plant which is well known. It produces a raceme of delicately odorous white flowers and beautiful oblong leaves with prominent parallel veins. The rhizome and roots are official. Smilax species. — The drug sarsaparilla is yielded by at least four different species of Smilax. These are mostly vines with woody or herbaceous, often prickly stems and leaves with petioles which have a pair of persistent tendril-like appendages. The flowers are small, mostly greenish, dioecious and in axillary umbels. The fruit is a globose berry. Not a great deal is known of the species which yield the drug, with the exception of Smilax mcdlca, which yields the Mexican or Yera Cruz sarsaparilla. In Smilax mcdica the leaves vary from more or less cordate to auriculate- hastate; in Smilax officinalis, which yields the native Jamaica sarsaparilla, they are ovate, as they are also in Smilax papyracea, which yields Para sarsaparilla. The Jamaica Sarsaparilla, official in the British Pharmacopoeia, is obtained from plants of Smila.\' 488 A TEXT-BOOK OF BOTANY. ornata growing in Costa Rica and subsequently shipped to Jamaica. Nothing is known of the plant yielding Honduras sarsaparilla, although this drug has been in use for nearly four centuries. It FIG. 269. Flowering plant of (.<>!( hicum Burmanu, a form producing very large corms and extensively cultivated in Holland. is said to be derived from Sniila.v officinal is. The sarsaparilla plants have short rhizomes which give rise to long roots, which are the part used in medicine. A DRAGON'S BLOOD, re.-embling that derived from Calamus CLASSIFICATION OF ANGIOSPERMS. 489 Draco, is obtained from Dracccna Draco, a tree growing in the Canary Islands. Some of the trees of this species are of historic interest, as the dragon tree of Orotava, which is 46 feet in circum- ference at the base. A number of the plants of this family contain saponin, as the species of Smilax. Some contain coniferin and vanillin, as Aspar- agus officinalis. Some of the group contain glucosidal principles which under the influence of ferments yield ethereal oils contain- FIG. 270. A field of Aloe plants, growing in the Riversdale District, Cape Colony. The stems are simple, with one or more clusters of leaves; the latter are from 3 to 6 dm. in length, fleshy and very thorny-prickly at the margin. — Reproduced by permission of the Philadelphia Commercial Museum. ing sulphur, as the various species of Allium. Garlic (Alliuui sativum) contains a glucoside, allisin, which on hydrolysis with an oxidase (allisin) forms the essential oil of garlic. A number also are quite poisonous when fresh but edible when cooked. b. AMARYLLIDACE^E OR AMARYLLUS FAMILY.— This group is of special interest because it includes the Agave or Century plant. This is a characteristic genus of plants of the hot and arid regions of North America. The best known of these 490 A TEXT-BOOK OF BOTANY. is the CENTURY PLANT (Agave americana), which is one of the most important economic plants of Mexico. The stem axis of the plant is very short and the thick, fleshy leaves form a tuft at FIG. 271. Plant of Aletris farincsa showing characteristic rosette of lanceolate leaves at the base and portion of long slender scape with numerous tubular flowers. The plant is common in dry coniferous woods in the eastern part of the United States. the summit. The leaves are lanceolate, with spinose margins, and furnished with stout terminal spines. The leaves as well as the roots contain a large amount of mucilage which retains water and CLASSIFICATION OF ANGIOSPERMS. 491 FIG. 272. Swamp Pink (Helonias bullata) is a rather rare plant found only in certain localities, particularly in wet places, extending from southern New York to Virginia. It produces a tuberous root-stock, and the evergreen leaves are clustered near the base of a naked scape which bears in the early spring a short raceme of purplish flowers. This should not be confounded with the plant yielding the drug known as Helonias or false unicorn root, the latter being derived from Chanuzlirium luleum, and at one time known as Helonias dioica. — After Troth. 492 A TEXT-BOOK OF BOTANY. thus helps to adapt the plants to these arid regions. The plants grow slowly and may flower when they are ten or twelve years old. The Agaves contain saponin and other principles of medicinal value. They yield a number of other products, as follows : PULQUE, a fermented drink of the Mexicans ; MEZCAL, a distilled drink resembling rum; various fibers, as SISAL HEMP, ' Hene- quen ' or '' Sacci," etc. Other members of the Amaryllidaceae likewise find use as medicines and as foods, many of them being cultivated as ornamental plants, as Narcissus, Hymenocallis, Crinum, and Amaryllis. c. DIOSCOREACEvE OR YAM FAMILY.— The plants be- longing to this family are twining shrubs or herbs with tubers either above or below ground. The general characters of the plants are shown in the wild yam-root (Dioscorea villosa) of the United States (Fig. i8'o). Several species, notably, D. Batatas, yield the YAMS or Chinese potatoes of commerce. Many of the species of Dioscorea, as well as other members of this family, contain active principles which, like those of the Aracese and Liliaces, are destroyed on heating. The rhizome of Taunts couununis contains saponin, and Rajania subamarata con- tains tannin. d. IRIDACE^E OR IRIS FAMILY.— The plants of this fam- ily are perennial herbs with mostly equitant (bilateral) leaves and horizontal rhizomes, or corms. The flowers are regular or irregular and with a petalloid stigma (Fig. 254, B). Iris rcrsicolor is a flag-like plant, commonly known as the LARGER BLUE FLAG, and found abundantly in the marshes and wet meadows of the Eastern United States. It is distinguished by its tall stems and sword-shaped, somewhat glaucous leaves. The flowers are violet-blue. The rhizome somewhat resembles that of calamus, but is of a dark brown color and contains 25 per cent, of acrid resins, a volatile oil, starch, and tannin. Iris florcntina, which yields the ORRIS ROOT of commerce (Fig. 190), is a plant cultivated in Middle and Southern Europe, and closely resembles the above-mentioned species. The rhizome con- tains a volatile oil resembling that found in violets, and is used in perfumery. Orris root is also obtained from Iris gcnnanica and /. pallida. The violet odor is developed on keeping the rhizome a vear or two. CLASSIFICATION OF AXGIOSPERMS. 493 Crocus satiz'iis, the orange-red stigmas of which have been used in medicine since ancient times, is an autumnal-flowering plant. The flowers are lilac-purple, somewhat like those of Colchicum, and occur at the summit of a scape rising 15 to 20 cm. above ground. The leaves are linear and rise directlv from a more or o •> less globular corm. The plant is cultivated in Spain and other parts of Europe and in the United States as well. The stigmas constitute the drug SAFFRON (Crocus), which was formerly official, and contain a coloring principle, I part of which will impart a distinct yellow color to 100,000 parts of water. Saffron contains a yellow glucoside, CROCIN, which is soluble in alcohol but not in water, and is colored blue by sulphuric acid. The drug also con- tains 7.5 to 10 per cent, of a volatile oil, which appears to be derived from a coloring principle that resembles carotin ; and the bitter principle picro-crocin. e. JUNCACE/E OR RUSH FAMILY.— These are grass-like marsh plants, which are distinguished by the fact that the flowers are small, with a 6-parted glumaceous perianth, and the fruit is a loculicidally dehiscent capsule. The stems are mostly solid, slen- der, usually arise in tufts from the rhizome, and are characterized by stellate parenchyma cells, among which are large, intercellular spaces, the latter also being characteristic of the leaves. The rushes are principally found in cold and temperate regions. Several species of Juncus and Luzula have been used in medi- cine, particularly in Europe. The seeds of Luzula compestris, a common wood rush of the United States naturalized from Europe, are edible. Soft rush (Juncus effusus) and Hard rush (/. conglomeratiis) are used in Japan in the manufacture of rush matting. In Holland the rush is grown on the embankments along the coast to prevent the action of the tides. VIII. ORDER SCITAMINALES OR SCITAMIXE.E. The plants of this order are mostly found in the Tropics and are perennial herbs with fleshy rhizomes. The leaves are large, more or less elliptical and pinnately veined. The leaf sheaths close tightly around each other and form a kind of false stem. The flowers are epigynous, unsymmetrical or zygomorphic, and fre- quently only one stamen is completely developed. 494 A TEXT-BOOK OF BOTANY. a. THE ZINGIBERACE^: OR GINGER FAMILY is dis- tinguished from the other Scitaminese by the fact that the seeds have endosperm as well as perisperm. The plants are rich in volatile oils, and a number are used in medicine and perfumery. Zingiber officinale yields the official ginger (Fig. 273). From a creeping, fleshy, branching and laterally compressed rhizome (Fig. 187) arises a stem about I M. high bearing numerous lanceo- late leaves. The flowering stalk arises directly from the rhizome, terminating in a spike which bears flowers having greenish-yellow petals with violet or purple stripes. Elettaria Cardanwnium (E. repens) yields the cardamom of the several pharmacopoeias (Fig. 237). The plant has a leafy as well as floral stem which rises from a tuberous rhizome. The leaves are broadly lanceolate. The flowers are greenish-white, the labellum (consisting of two petal-like staminodes) being bluish. The fruit is a capsule, and the seeds are the part used in medicine. The so-called PARADISE GRAINS are the seeds of Amoniuui Melegueta growing in Western Africa. They are about 3 mm. in diameter, dark brown, nearly smooth, friable, and contain a vola- tile oil. GALANGAL, which is used in perfumery, is the rhizome of Alpinia Galanga growing in the East Indies and cultivated in China and Bengal. It is frequently referred to as k Galangal major " to distinguish it from the rhizome of Alpinia officinaruui growing in China near Hainan. Galangal occurs in short, branched pieces of a reddish-brown color, with numerous circular scars, and has an aromatic and pungent taste. It contains 0.5 per cent, of a volatile oil, the principal constituent of which is cineol ; a pungent principle, galangol ; an acrid, pungent resin; 25 per cent, of starch ; and three crystalline principles. CURCUMA or TURMERIC is the rhizome of Curcuma longa, a reed-like plant which is largely cultivated in India and other tropical countries. In preparing the rhizome for market it is sub- jected to a scalding or parboiling process which agglutinates the starch in the cells. While turmeric is used as a condiment, it is also used on account of its color as an adulterant of mustard, rhubarb, and other articles, but is very easily detected. Several forms of curcuma are found in commerce, as " round curcuma," CLASSIFICATION OF ANGIOSPERMS. 495 consisting of the main rhizome, and ' long- curcuma/' composed of the short branches. They occur in cylindrical or ovoid pieces, FIG. 273. Zingiber officinale, the rhizome of which constitutes the Ringer of the market. Entire plant showing rhizome and roots, a leaf-branch and a flower-branch, as also scars of previous year's growth after decay of leaf- and flower-branches. A, entire flower; B, sec- tion of flower showing beak-like appendage at the apex of the fertile stamen, which encloses the style; C, three- parted labellum or irregular segment of corolla showing 2 tooth - like staminodes (rudiments of stamens) at the base; D, the ovary with lower portion of style and two epigynous, filiform processes which secrete nectar; E, apex of funnel-shaped, fringed stigma. — After Berg and Schmidt. 2 to 5 cm. long, of a yellowish-brown color externally, bright yel- low internally, and aromatic odor and taste. Curcuma contains 496 A TEXT-BOOK OF BOTANY. I per cent, of volatile oil containing phellandrene and turmerol ; 0.3 per cent, of a yellow crystalline principle, CURCUMIN, which is soluble in alcohol, sparingly soluble in water, forms reddish-brown solutions with alkalies and is converted into vanillin with weak oxidizing agents. It also contains considerable starch and a small quantity of an alkaloid. Other families of the Scitaminese are of great importance on account of the food-products obtained from them, as the Musa- cece, which contains the group of plants to which the BANANA (Musa paradisiaca and M. Sapientum) belongs. To the Canna- cccc belong the cultivated Cannas, one of them, Canna edulis, being grown extensively in the West Indies and Australia as a vegetable, and another, Canna coccinea, which grows in the West Indies and South America, furnishing Tous les mois," the arrow-root starch of the English and French. To the Maranta- cccc belongs Maranta anmdinacea, which is cultivated in tropical America, and the rhizome of which yields the starch, MARANTA ARROWROOT (Fig. 88, B), and is largely used in the preparation of infants' food. IX. ORDER ORCHIDALES OR MICROSPERM^. The most important family of this order is the ORCHIDACE^: or ORCHID FAMILY. The orchids are the most highly specialized of the Monocotyledons. They are perennial herbs with diverse habits, many tropical species being epiphytes, and of varying mor- phological structure, which is particularly evident in the zygo- morphic flowers. The perianth consists of 6 segments. The 3 outer correspond to sepals and are similar. Two segments of the inner circle correspond to petals and are alike, while the third, which is known as the LIP, is remarkably modified, being usually larger, often spurred, and frequently reversed, being turned fo-r- wards and downwards by the twisting or torsion of the ovary. Only one of the stamens — the anterior of the external whorl — is developed and bears an anther. The other stamens are entirely wanting or present as staminodes (except in Cypripedium and the Apostasiese). The filament is united with the style to form a column, the so-called " stylar column," and the anther is thus placed on its apex, and behind the stigma. The 3 carpels form a unilocular ovary with 3 parietal, deeply bifid placentae. The fruit CLASSIFICATION OF ANGIOSPERMS. 497 is a pod or capsule, which dehisces mostly by means of 6 valves, and contains numerous minute seeds, which are without endo- sperm, and the embryo of which lacks frequently any trace of external organs. The seed-coat is membranous and loose. FIG. 274. A fruiting plant of Vanilla planifolia, an epiphytic orchid, which is indige- nous to Mexico and extensively cultivated in tropical countries, especially in Mexico and Java. The photograph is of a plant growing in Dominica, an island of the West Indies, and shows the long, elliptical leaves, also some of the long, slightly curved, slender pods. The latter are not fragrant, but develop their characteristic aroma by a process of slow curing. — Reproduced by permission of The Philadelphia Commercial Museum. planifolia, which yields the official vanilla, is a high- climbing plant with long internodes and distinct nodes from which arise more or less oval or broadly lanceolate, somewhat fleshy leaves and also commonly a single aerial root. The long stem is terminated by a raceme, flowers also arising in the axils of the 498 A TEXT-BOOK OF BOTANY. FIG. 275. Moccasin Flower or Pink Lady's Slipper (Cypripedium acaule), one of the commonest and most beautiful of the orchids, found growing in sandy and rocky woods from Newfoundland to North Carolina, and westward from Minnesota to Kentucky. The crimson pink flowers are solitary at the summit of long scapes; the lip is large inflated, slipper-shaped, drooping and with a fissure in front instead of a circular opening as in the other species. — After Troth. leaves for some distance back on the stem. The flowers are yel- lowish-green and the segments of the perianth are similar, and erect or spreading. The lip is united with the column, forming a CLASSIFICATION OF ANGIOSPERMS. 499 FIG. 276. Round-leaved Orchis (Habenaria orbiculala), an interesting orchid found growing in rich deep woods in the north temperate regions of the United States. It has a leafless scape, at the base of which are two orbicular or elliptical leaves spreading flat on the ground. The flowers are in a loose raceme, greenish-white, the lip being oblong linear and about the same length as the spur. — After Troth. 500 A TEXT-BOOK OF BOTANY. FIG. 277. White Fringed Orchis (Habenana blephari glottis), an attractive and rather common orchid growing in bogs and peaty lands throughout the eastern and centra! United States. The stems are from 4 to 6 dm. in length, terminated by many-flowered spike. The flowers are white, the lip being copiously fringed and the spur about 2 cm. in length. — After Troth. cylindrical body which is strongly concave on one side and spread- ing at the upper portion. The pollinia are granular. Pollination CLASSIFICATION OF ANGIOSPERMS. 501 may be effected by insects, but is usually brought about by arti- ficial means (hand-pollination). The fruits require several months to become fully grown, and an equal period of time is necessary for their maturity, which is indicated by their yellow color. They are then gathered and cured by alternately steaming and drying them, until they acquire the dark brown color and the odor of the commercial article. Vanilla is cultivated in all tropical countries where the temperature does not fall below 18° C., and the humidity is considerable. Usually vanilla culture is combined with that of Cacao. The plants begin to yield fruits the third year and continue bearing for thirty or forty years (Fig. 274). The yellow-flowering Cypripediums of the United States (C. pari'iflorum and C. parviftorum pubesccns) yield the cypripedium which was formerly official. The plants are a foot or two high. The leaves are oval or elliptical (in the latter) or elliptical or lanceolate (C. parviHorum) . In C. pubcsccns the lip is pale yellow with purple veins, 25 to 50 millimeters long, and possesses a tuft of white, jointed hairs at the throat. In C. parviflorum the lip is smaller and non-hairy. C. acaule is shown in Fig. 275. The root-stocks of a number of Orchids are rich in mucilage and yield the drug salep or a product resembling it. Salep occurs in the form of globular or somewhat flattened, more or less trans- lucent, light yellowish-brown tubers, 2 to 4 cm. long, of a horny texture and a mucilaginous taste. The principal constituent is mucilage, which originates in the cell-contents. It may contain in addition either starch or sugar. While the Orchidaceae, which contains about 6,000 species, ranks second in numbers to the Composite, there is probably no family which exceeds it in interest. The plants are extensively cultivated, and some of their flowers are the highest priced known in the commercial world. There are few localities in which there are not some orchids to be found, illustrations of several of which are here shown (Figs. 275 to 279). B. CLASS DICOTYLEDONE^E. The following are some of the prominent features of the Dicotyledons: (i) The leaves are reticulately (open) veined and usually with an irregular margin, being sometimes deeply lobed ; 502 A TEXT-BOOK OF BOTANY. FIG. 278. Arethusa bulbosa, an Orchid growing in bogs from Newfoundland to South Carolina, and west to Minnesota. It produces a solitary magenta-crimson flower on a long, slender scape, in the sheaths of which a solitary linear leaf arises and protrudes after the flower opens. In the illustration are shown a number of plants, some of which show the small bulbs at the base. — After Troth. (2) the parts of the flower are usually in circles of 2 to 5 each; (3) the stems and roots generally increase in thickness by means of a cambium, and the vascular bundles are open, varying from CLASSIFICATION OF ANGIOSPERMS. 503 v* " *? FIG. 279. Rattlesnake Plantain, a rather common orchid, variously known as Epi- Pactis, Peramium, or Goodyera Pubescens. It is generally found growing in coniferous woods and characterized by the dark-green basal leaves with their prominent nerves and numerous white reticulating veins. The flowers are greenish-white, numerous and crowded on the erect scapes. — After Troth. simple collateral to bi-collateral ; annular rings are formed in the perennial stems; (4) the germinating plant usually has two coty- ledons which are opposite each other. The Dicotyledons are divided into two series or sub-classes, depending upon whether 504 A TEXT-BOOK OF BOTANY. the parts of the corolla are distinct or are united, namely, the Archichlamydese and Metachlamydese. ARCHICHLAMYDE^: OR CHORIPETAL^E. The Archichlamydeae or Choripetalae comprise those dicoty- ledonous plants in which the petals are separate and distinct from one another or are entirely wanting. I. ORDER PIPERALES. The plants of this order are mostly tropical herbs and shrubs and possess very small flowers which have neither petals nor sepals. The leaves are simple and without stipules, the most important family medicinally, as well as in other ways, being the PIPERACE.E, to which the following medicinal plants belong. Piper nignun is a woody climber that has leathery, grayish- green, ovate-elliptical leaves (Figs. 281, 282), with three prominent middle nerves and two side nerves ; the flowers are perfect, sessile and form an elongated fleshy spike ; the fruit is a berry which is yellowish-red when ripe. The unripe fruit constitutes the BLACK PEPPER of commerce. WHITE PEPPER is the ripe berry of Piper nig nun from which the epicarp is removed, while " LONG PEPPER^ is obtained from Piper longum, an entirely different plant, and consists of the entire spikes with immature fruits. Piper Ciibeba is a climbing perennial, with leathery elliptical- ovate or long elliptical leaves ; the flowers are dioecious and arranged in spikes ; the fruit is a berry, the pedicel becoming much elongated after fertilization. The unripe fruit is the part used in medicine and is official as cubeb. Piper angnstifoliuui yields MATICO, formerly official. The plant is a shrub growing in Central and South America and is characterized by its long, oblong-lanceolate, deeply reticulate, very hairy leaves. The flowers and fruits are very small and arranged in long, slender spikes, which are frequently found in the drug. Matico contains 2 to 3 per cent, of a volatile oil, containing a stearoptene matico camphor, which appears to be the most im- portant constituent. It also contains an acrid resin, a bitter prin- ciple, and a crystalline principle, artanthic acid. Other related CLASSIFICATION OF ANGIOSPERMS. 505 K FIG. 280. Diagrams of cross sections of the flowers of a number of families of dicoty- ledonous plants showing the number and position of the parts with reference to each other: t, stem of plant; f, foliage leaf; b, bracts or leaves on the flower-stalk; s, sepals; p, petals; a, stamens; c, ovary; per, perianth. A, Linaceae; B, Cruciferae; C, genus Citrus; D, Rosaceae; E, Berberidaceae, showing nectaries (k) on the petals; F, Lauracese, showing staminodes (g) ; G, epigynous flower of Rubiaceae; H, Ericaceae; I, Labiatae, showing position of other flowers (sv) in the cymes; J, Violaceae showing spurred stamens; K, Campanulacea?, showing bracts (a, /3) the relation of the sepals (1,2,3,4 and 5), and two pos- terior hairy stamens; L, Leguminosae, showing the large posterior petal (p) known as the Vexillum or standard, the two lateral petals (v) situated under the standard known as alee or wings, and the two anterior petals which are covered by the wings and partly cohering to form a prow-shaped body called the carina or keel (k). — Adapted from Warming. 5o6 A TEXT-BOOK OF BOTANY. FIG. 281. Black pepper (Piper nigriiiri), a climbing shrub growing in Botanic Gardens, Port of Spain, Trinidad. The illustration shows the ovate-elliptical leaves, opposite which are the fruiting spikes, which when ripe are of a yellowish-red color. The plant has been introduced into many tropical countries and is not infrequently seen in botanic gardens throughout the civilized world. — Reproduced by permission of The Philadelphia Commercial Museum. species of Piper are used in tropical America similarly to Piper angnsti folium. The leaves of a number of species of Piper (known as " betel CLASSIFICATION OF ANGIOSPERMS. 507 in 2. w n o -o $ re ~ >-) _. tn 3 - - 3 fp cn >-• 3 3 -t 3 TO cn -_, r* ^ re 5. o re o> O. 3 5o8 A TEXT-BOOK OF BOTANY. leaves ") are mixed with the Areca nut and lime and constitute what is known as " BETEL," which compound is used for chewing, in India and other countries, chiefly on account of its astringency. The root of Piper methysticum is also chewed, and when mixed with the milk of the Cocoanut yields an intoxicating drink which is used by the inhabitants of the Sandwich Islands. The dried root has been used in medicine under the name of METHYSTICUM or KAVA-KAVA. It consists of large, branching, soft, spongy, dark brown pieces, which are tough, fibrous, and with a pungent, somewhat bitter taste. Kava-kava contains 3 resins, one of which has marked anaesthetic properties ; an alkaloid, kavaine ; a neutral body, methysticin ; and about 50 per cent, of starch. The drug is free from calcium oxalate crystals, these being usually wanting in the Piperacese. II. ORDER SALICALES. This order comprises but a single family, namely, the SALI- CACEJE or \Yillow Family, to which belong the willows and pop- lars. The plants are dioecious shrubs and trees ; the flowers being in a in cuts or catkins and without petals or sepals. The fruit is a capsule containing many seeds which are small and with long, silky hairs at the base. The barks of a number of the members of this group contain glucosides, as salicin, which is found in Salix alba, the white willow of Europe and the United States, and the brittle willow Salix fra- gilis; and populin, which is found in the white or silver-leaf poplar (Populus alba} of Europe, Asia, and the United States and Populus pyramldalis of Italy. These principles are also found in other species of willow and poplar. A number of the barks con- tain a yellow coloring principle allied to quercitrin, as Salii" dapJi- noides of Europe and Salix alba. Tannin is a common constituent in both the willows and poplars. The buds of many of the poplars contain in addition a volatile oil which is in the nature of a di- terpene, as those of Populus pyramldalis. Populus balsamifcra, the tacamahac or balsam poplar of the United States and Canada, furnishes the HALM OF GILEAD buds which are coated with an oleo-resin that gives them their aromatic properties. Populus CLASSIFICATION OF ANGIOSPERMS. 509 nigra yields a volatile oil, of which the important constituent is humulene. The charcoal used medicinally is prepared by burning the wood of the young shoots of the white and black willow, poplar, beech, or linden without access of air. * III. ORDER MYRICALES. This group somewhat resembles the Salicales in that the flowers are in aments. The flowers are either pistillate or staminate, and mostly dioecious in our native species. The most important family is the MYRICACE^E or Bayberry Family. The genus Myrica is especially characterized by the fact that the outer layer of the drupe is waxy. This is particularly true of the following species : Myrica cerifera, the wax myrtle of the sandy swamps of the United States, contains a volatile oil. The fruit of sweet gale (M. Gale) yields a volatile oil containing a camphor. The sweet fern (Comp- tonia p ere grina) found in the United States yields a volatile oil resembling that of cinnamon. The rhizome of this plant contains also tannin and possibly gallic and benzoic acids. IV. ORDER JUGLANDALES. The plants are trees with alternate, pinnately-compound leaves. The staminate flowers are in drooping aments, the pistillate being solitary or several together. The flowers are monoecious and have a more or less distinct perianth consisting of 3 to 6 lobes. The fruit is a kind of drupe formed by the union of the torus with the wall of the ovary. There is but one family in this order, namely, the JUGLANDACE^E (Walnut family), which includes the hickory (Hicoria) and walnut. The black walnut (Juglans nigra) of the United States yields a valuable timber and an edible nut; the white walnut or butternut (/. cinerea) of the United States yields the butternuts which are edible, and a bark which has medicinal properties and was formerly official under the name of JUGLANS. It contains about / per cent, of a yellow, crystalline acrid principle which is colored purple with alkalies ; 2 to 2.5 per cent, of a crystalline resin ; volatile oil, tannin, sugar, and a fixed oil. The bark of the stems of the butternut tree is used in dyeing. The ripe fruits are edible, as also- the green nuts when 510 A TEXT-BOOK OF BOTANY. pickled. The sap of the tree contains a sugar. The wood, though inferior to black walnut, is used in cabinet making. /. regia, native of Persia and cultivated in various parts of Europe and California, yields the edible ENGLISH WALNUT. The following species of hickory yield edible nuts : The shell- bark hickory (Hicoria ovata) ; the pecan (H. pecan) common from Illinois southward; and western shell-bark hickory (H. sulcata). The wood of these as well as H. glabra and other species of hickory is used where strength and elasticity are required. Coloring principles are found in the barks of a number of species and are used for technical purposes. The following con- tain yellow coloring principles : Hicoria ovata, H. sulcata, and H. glabra (pig-nut hickory) ; green coloring principles are found in H. tomentosa, and yellowish-brown principles in Juglans nigra, J. cinerea, and /. regia. The fatty oils from the cotyledons (kernels) of both hickory- nuts and walnuts are articles of commerce, and they have been used in medicine. V. ORDER FAGALES. The plants are trees or shrubs with alternate, petiolate, simple, pinnately veined leaves. The flowers are in aments, monoecious, and with a more or less distinct perianth. The fruit is a nut which is subtended by the mature involucre (bur or cup) or samara, the seeds being without endosperm (Fig. 283). a. BETULACE^: OR BIRCH FAMILY.— The plants are aromatic trees or shrubs and are represented in the United States by such trees as hornbeam (Carpinus), ironwood (Ostrya), and birch (Betula) ; and by such shrubs as the hazelnut (Corylus) and alder (Alnus). The plants yield a volatile oil consisting largely of methyl salicylate. The bark of the sweet birch (Betula lenta) yields the oil of betula which is official and closely resembles the oil of wintergreen. The bark of a number of plants of this family yields tannin and yellow coloring principles. A number of species of Betula yield a sweet sap, as B. lenta, and B. Bhojpattra of Rus- sia. The nuts of some species are edible, as the filbert or hazelnut of Europe (Corylus Avellana), the hazelnut of the Orient (C. Coiurna), the American hazelnut (C. americana). CLASSIFICATION OF ANGIOSPERMS. 511 b. FAGACEyE OR BEECH FAMILY.— This family includes some of our largest forest trees, these being rather characteristic of temperate regions. They are all highly valued for their timber, and yield other valuable products besides. One notable character- istic is that all of the chestnuts and oaks and some of the beeches FIG. 283. White oak (Quercus alba): A, characteristic, lobed leaf; B, young branch showing pistillate (p) and staminate (s) flowers; C. hairy bracts of a staminate flower; D, group of hairs from bract; E, stamen; F. pollen grains; G, cluster of pistillate flowers; H, acorn with cupule; I, starch grains from acorn, which vary from 10 to 25 M long; J. trans- verse section of bark showing cork (k). stone cells (st), bast fibers (b). crystal fibers (ca), medullary rays (m), parenchyma (p); K, longitudinal section of bark showing end of bast fiber (b) crystal fibers (ca) and parenchyma cells (t) containing tannin. contain tannin in the wood, bark, and leaves. The oaks are further notable in being prone to the attack of gall-producing insects (various species of Cynips) whereby the peculiar excrescences known as galls are formed on the leaves and young shoots. Among the oaks which yield galls rich in tannin are the following: Quercus infectoria of the Mediterranean, which yields the official Turkish 512 A TEXT-BOOK OF BOTANY. or Aleppo galls (pp. 206, 334) ; Quercus Robur, which is some- times divided into Q. pubcscens and Q. pedunculata, yields a European gall; the live oak (Q. virginiana) of Texas; and Q. lobata of California. Various oaks of the Southern States also produce "ink balls " or " ink galls," as Q. coccinea and Q. imbri- caria. Several species of oak are used in the tanning industry, as that of white oak (Quercus alba), red oak (Q. rubra), Spanish oak (Q. digitata), and black oak (Q. velutina), all of North America ; Q. pedunculata and sessiliflora of Germany, and Q. den- tata of Japan. The glucosidal coloring principle quercitrin is found in the bark of Quercitron or black oak (Q. velutina) . 0. coccifera of Southern Europe yields a red coloring principle which is used in dyeing. The wood of the American beech (Fag us ainericana) and of the European red beech (F. sylvatica) yields a tar from which on distillation the official CREOSOTE is obtained. The cork of commerce which is used for a variety of purposes is derived from the bark of several species of Quercus, namely, Q. Suber and Q. Occident alls, growing in Spain, Southern France, and Algiers. The cotyledons of the seeds of the Beech family are rich in proteins, starch, and oil, and some of the nuts are edible, as the Spanish CHESTNUTS obtained from Castanca vulgaris, American chestnut from C. dcntata, and CHINQUAPIN from C. putnila (Fig. 202). VI. ORDER URTICALES. This order embraces three families which, while they agree in certain characters, are quite distinct in other ways. a. ULMACE^E OR ELM FAMILY— The plants are trees or shrubs with alternate, simple, serrate, petiolate leaves. The flowers are monoecious or dioecious, with a 4- to 6-divided peri- anth. The fruit is a i -seeded drupe, samara, or nut. The typical group of this family is that of the elms, of which the American or white elm (Ulmits americana) is the most prized for orna- mental purposes. The elms yield valuable timber, and the bark of ('hints campestris of Europe is used for tanning and dyeing be- cause of the presence of tannin and a yellow coloring principle. CLASSIFICATION OF ANGIOSPERMS. The inner bark of the red or slippery elm (Ulmus fulva) is used in medicine on account of its mucilaginous character (see Fig. 119, C). The tree has a gray, fragrant bark; leaves which are very rough above and become fragrant on drying, and the wood is reddish-brown. The samara is not hairy as in some of the other species. FIG. 284. View taken in Ceylon of a part of a grove of 4-year-old rubber trees (Ficus elastica). This tree is extensively cultivated in Ceylon and other portions of tropical Asia, and most all of the Asiatic rubber is produced by this tree. The trees may be tapped when 25 years old, and for 50 succeeding years yield 40 pounds caoutchouc every 3 years. — Reproduced by permission of The Philadelphia Commercial Museum. b. HORACES OR MULBERRY FAMILY.— The mem- bers of this family are herbs, shrubs, or trees, many of them con- taining a milk- juice or latex. There are many representatives in the tropical regions and some in temperate regions. The flowers are unisexual, with a 4- to 5-parted perianth, and occur in spikes or ament-like clusters. Cannabis sativa.- -This is the plant yielding hemp and also the 3^> 3 A TEXT-BOOK OF BOTANY. drug Cannabis indica. The plant is an annual branching herb from i to 3 M. high. The leaves are alternate above, opposite below, digitate with 5 to 1 1 linear-lanceolate, deeply serrate lobes. The flowers are dioecious, the staminate occurring in panicles and the pistillate in erect simple spikes (Figs. 409, 410, 412). From the inner bark of the stem, which is fibrous, the HEMP FIBER is prepared. FIG. 285. Several large rubber trees (Ficus elastica) growing in Java and showing the production of numerous aerial roots from the branches. It occurs in damp forests from the base of the Sikkim Himalaya eastward to Assam and Arracan. There are large government plantations in Assam, and it is also being cultivated in other provinces. Kurz remarks that it is frequent in Upper Burma, and that whole forests of the species are said to exist in the valley of Hookhoom. — Reproduced by permission of The Philadelphia Com- mercial Museum. Humulus Lupulus or hop is a twining perennial plant, curving to the right, with opposite, palmately 3- to 7-lobed (or simply dentate above) rough leaves (Fig. 286) . The flowers are dioecious, the staminate ones occurring in panicles and the pistillate in ament-like spikes. On the inner surface of each scale of the ament occur two flowers consisting of a membranous perianth CLASSIFICATION OF ANGIOSPERMS. 515 and a bicarpellary ovary with two long styles. After fertilization the aments become cone-like, and this compound fruit constitutes the hop of commerce. This fruit differs essentially from the true strobiles or cones of the Gymnosperms in that the seed in the latter is replaced by an akene. ' Hops " are extensively used FIG. 286. Hop vine (Humulus Lupulus): A, portion of branch with pistillate flowers (f) and cone-like fruit (s) ; B, portion of rachis of strobile with two scales enclosing akenes; C, pistil; D, hair from rachis; E, epidermis of scale; F, longitudinal section of akene show- ing coiled embryo; G, surface view of bract showing epidermis and cells containing calcium oxalate; H. cystolith of leaf; I, cystolith of stem; J, glandular hairs (lupulin). in the manufacture of various beers and to a limited extent in medicine. Ficus Carica, which yields the edible fig, is a deciduous tree from 3 to 7 M. high, and with large, 5-lobed, petiolate leaves. The flowers are situated in a hollow torus the walls of which 5i6 A TEXT-BOOK OF BOTANY. after fertilization become thick and fleshy, constituting the fruit. The best figs come from Turkey, Italy, Spain, and Provence. A large number of the plants belonging to the Moracese yield economic products, some of which, as the drug Cannabis indica obtained from Cannabis sativa, are powerful narcotics. HASH- ISH or BHANG is a preparation made from the dried leaves, stems, and flowers of the pistillate plants and is smoked either alone or with tobacco, or chewed in combination with other substances, or an intoxicating drink is made from it, it being extensively used by the inhabitants of Arabia, Persia, India, and other Oriental countries. The leaves of Ficus Ribes of the Philippine and Mo- lucca Islands are smoked like opium. The milk-juice of a number of plants belonging to the Moracese is the source of arrow poisons. The URARI POISON of Brazil is obtained from Ficus atrox; the IPOH ARROW POISON of Java and Borneo is derived from the Upas- tree, Antiaris to.i'icara. Many of the plants of the group contain emetic principles, as the COCILLANA BARK of Guarea Rusb\i, a tree of Bolivia. The milk-juice of quite a number of species of Ficus yields India-rubber or caoutchouc ( Fig. 128) , as Ficus elastica of the East Indies, F. toxlcaria of South America, F . elliptica and F. prinoides of New Granada and several other species of Brazil, Brosimum spurium of Jamaica, Cecropia pcltata of the West Indies and South America, and Castilloa elastica of Mexico and the West Indies. Ficus benghalensis of India and tropical Africa, and Ficus Tsicla of India, yield gum-lac. Ficus altissiuia and F. rcligiosa of tropical Asia yield shellac on the puncture of the stems by a hemipterous insect (Coccus lacca). A yellow coloring principle is found in Cudrania javanensis of tropical Asia and Africa, Chlorophora tinctoria of Mexico, Madura aurantiaca (Toxylon poiuifcrum) or osage orange, a hedge plant of North America; Ficus tinctoria of the Friendly Islands and F. asperrima of India. A fixed oil is obtained from Artocarpus Bluinci of Java. A large number of the plants of the Moraceae yield edible fruits besides the fig tree already described, as the BREAD-FRUIT trees (Artocarpus incisa) of the Sunda Islands and the JACK-TREE CLASSIFICATION OF ANGIOSPERMS. 517 (A. iutcgrifolia) of the East Indies, the WHITE MULBERRY (Morns alba) and the BLACK MULBERRY (Morns nigra). The leaves of the white mulberry (Morns alba), indigenous to China and cultivated since the twelfth century in Europe and now in cultivation to a limited extent in the United States, are the chief food of the silkworm. c. FAMILY URTICACE^E.— The plants belonging to the Urticaceae or Nettle family are chiefly herbs with mostly petiolate, stipulate, simple leaves. The flowers are small and with 2 to 5 distinct or more or less united sepals. The fruit is an achene ; the embryo is straight and surrounded by an oily endosperm. The stems and leaves of several of the genera are characterized by stinging hairs, this being especially true of the sub-group to which the genus LTrtica or stinging nettle belongs. Of the stinging nettles the following are used in medicine: Urtica dioica of Europe and naturalized in the United States, U. spatitlata of Timor, Laportea crennlata of tropical Asia, L. moroides of Queensland, and Girardinia palumta of India. In the small nettle (Urtica urens) of Europe and the LTnited States an alka- loid has been found, and Laportea stimnlans has been used as a fish poison. Boehmeria cordata of Brazil is used as a substitute for Arnica. The fibers of a number of the Urticaceae have been found useful, of which the following may be mentioned : Urtica cannabina of Asia, U '. dioica, U. urens and Boehmeria niz'ca of the Sunda Islands and China, the latter of which yields RAMIE. The akene of Debregeasia ednlis of Japan and the rhizome of Pousolsia tnberosa of China and Japan are edible. VII. ORDER PROTEALES. The members of this group are mostly shrubs and found prin- cipally in the Tropics and southern hemisphere, several species being cultivated in greenhouses for the sake of the beautifully colored flowers which are in crowded inflorescences. The order is represented by but a single family, namely, the Proteaceae. The leaves are leathery and vary even on the same plant from sim- ple to compound. The glucoside proteacin and a bitter principle are found in Leucadendron aryentcuin and L. concinnum, both 5i8 A TEXT-BOOK OF BOTANY. of Africa. A gum-resin is found in Grevillea robusta of Aus- tralia, and a tannin in the bark of Louiatia obllqua of Chile. A golden-yellow coloring principle is obtained from the flowers of Persoonia saccata of Australia. The wood of Protea grandi- flora of Abyssinia is used in wagon building, and Leucospermum conocarpum of Cape Colony yields a valuable red wood and a tan bark. Banskia ccniula of Australia and the sugar-bush (Protea inclli- fera] of Australia and P. speciosa have a sugary cell-sap. The oily seeds of the Chilean hazelnut (Guevina Avellana) are highly prized as food by the inhabitants. The seeds of Brabeium stellati- follum or wild chestnut of Cape Colony are poisonous when fresh, but on roasting they become edible and are used as a substitute for coffee. VIII. ORDER SAXTALALES. This order embraces a number of families which are quite distinct in several respects. a. LORANTHACE^: OR MISTLETOE FAMILY.— The plants are half-parasites with well-developed leaves containing chloroplastids. They live on trees by means of haustoria. To this family belongs the American mistletoe (Phoradcndron fla- vescens) , parasitic on oaks, elms, the tupelo (Nyssa), red maple and other deciduous trees. The white, globose berries of this plant are quite poisonous, as are also those of the European mistle- toe (Vise urn album} and the oak mistletoe of Southern Europe (Loranthits curopccus). Viscniu album contains a volatile alka- loid, VISCIXE, a glucoside and a resinous principle. This sub- stance serves to attach the seeds to the barks of trees, where they germinate, and it is used in the manufacture of BIRD-LIME, which owing to its viscid character is used to catch small birds. b. SANTALACE^E OR SANDALWOOD FAMILY.— The plants are chlorophyllous herbs or shrubs which are common in warm countries, and many of which are parasitic on the roots of other plants. A number of them contain volatile oils, as the wood of various species of Santalum. The official oil of sandal is obtained from the scented wood of the white sandalwood (Santalitin album ) , a small tree growing wild and also cultivated in India and the CLASSIFICATION OF AXGIOSPERMS. 519 East Indian Archipelago. The wood from the East Indies is known as Macassar sandalwood and yields 1.6 to 3 per cent, of oil, while the Indian wood yields 3 to 5 per cent. The oil consists of 90 to 98 per cent, of santalol. Fiji oil of santal is obtained from 6\ Yasi; and Australian oil of santal from Fusanns aciuninatus and F. spicatus. The Chinese oil is obtained from Santalum Freycinctianum and *S\ Preisci. c. FAMILY BALANOPHORACEJE.— The plants of this group are indigenous to tropical and sub-tropical regions. They are root-parasites and develop tuberous rhizomes and fleshy shoots which are yellow and without foliage leaves. Balanophora clon- gata of Java grows on the roots of Ficus and other plants, and contains a large quantity of wax and resin. Sarcophyte sanguined of Cape Colony, which lives on the roots of certain Acacias, con- tains a principle with the odor of scatol. Cynomorium coccineum, found in the countries bordering the Mediterranean, has a blood- red, astringent sap. The torus of the flower of Langsdorffia Jiypo- goca of tropical America is edible. The plant is also rich in wax, and in New Granada it is sold under the name of ' Siejas " and burnt like a candle. IX. ORDER ARISTOLOCH TALES. This order includes two families which are very different in their general habits, a. The Rafflesiaceae are parasitic herbs that are almost devoid of chlorophyll. The reddish vegetative parts penetrate into the tissues of the host, and from these arise almost mushroom-like flowers which in the case of Rafflesia Arnoldil of Sumatra are i M. in diameter, being probably the largest flowers known. The plants of this family are rich in astringent substances. b. ARISTOLOCHIACE^: OR BIRTHWORT FAMILY. -The plants are non-parasitic herbs or shrubs, some of which are twining. The leaves are simple and in many of the plants more or less cordate and reniform. The flowers are perfect and the perianth is 3- to 6-lobed. While the flowers of our native species are rather small and insignificant, those of the tropical plants are extremely curious, being generally of some striking color and of various odd forms. Aristolochia reticulata is one of the plants that furnishes the 520 A TEXT-BOOK OF BOTANY. official drug serpentaria (see Vol. II). From a slender rhizome with numerous hair-like roots arise one or more short, leafy branches which are more or less simple, somewhat hairy, and bear oblong-cordate, prominent-reticulate, hairy leaves (Fig. 287). The flowers are borne on slender, scaly, basal branches ; the calyx tube is purplish and curved like the letter " s," being enlarged around the ovary and at its throat. The fruit is a capsule containing numerous flat or concave seeds. An allied species, Aristolochia Serpentaria, furnishes the drug Virginia snakeroot. It is a more delicate plant, the leaves being ovate-lanceolate, acuminate ; the flowers are solitary, and in some cases cleistogamous. This species is found growing in the United States, more especially east of the Mississippi, while Aristolochia reticulata is found west of the Mississippi from Arkansas to Texas. The plants of this genus contain volatile oils, and in addition to the two species mentioned 45 other species are used in medicine in various parts of the world. Asanun canadense (Canada snakeroot or wild ginger) is a plant common in the Northern United States and Canada (Fig. 288). The long and slender rhizomes are used in medicine. They are 5 to 15 cm. long, about 2 mm. thick, more or less bent and curved, purplish-brown externally ; whitish internally ; the bark is thick, wood with about 12 fibrovascular bundles, pith large ; the odor is aromatic ; the taste pungent and bitter. The drug con- tains 2 to 3 per cent, of a volatile oil containing a fragrant body, asarol ; a pungent, fragrant resin ; a yellow coloring principle which is colored dark green with ferric salts ; and starch. The volatile oil obtained from A. curopocum contains a principle (asa- rone) which forms irritating vapors on heating. X. ORDER POLYGON ALES. This order is represented by a single family, the POLYGOXACE^ or Buckwheat family. The plants are mostly herbs, but include some twining vines and shrubs. The leaves are simple, mostly entire, and characterized by having a stipulate appendage (ocrea) which sheaths the stem. The flowers are small, perfect, and with a 2- to 6-parted perianth. The fruit is a 3- to 4-angled akene. The embryo is either straight or curved, and the endosperm is mealy. CLASSIFICATION OF ANGIOSPERMS. FIG. 287. Southern serpentaria (Aristolnchia reticulata) showing the cordate, reticu- lately-veined leaves, and the clusters of irregular flowers on the lower part of the stem. "—After Carson. 522 A TEXT-BOOK OF BOTANY. Rheum officinale is the source of the " South China " rhubarb from Szechwan, Kanzu, and Shensi. The plant is a perennial herb resembling the garden rhubarb. The rhizome is vertical and gives rise to a leafy branch terminated by the inflorescence, which is a panicle. The leaves are large, with a sub-cylindrical petiole, FIG. 288. Wild Ginger (Asarum canadense). A, showing habit of plant, consisting of underground root-stock, the kidney-shaped leaves on long petioles, and the short peduncled, bell-shaped flower which develops close to the ground; B, longitudinal section of flower, and C, a transverse section of flower. — Bicknell, in Bulletin Torrey Bot. Club, Nov., 1897. a cordate or orbicular lamina which is either entire or coarsely and irregularly dentate. There are several nearly related species which also yield the drug. Rheum pal mat u in of Northern China has leaves which are lobed or deeply incised, which character is especially -marked in the variety tanguticum. Rheum Rhaponti- c it in, which yields English rhubarb, has leaves which are heart- CLASSIFICATION OF ANGIOSPERMS. 523 shaped at the base and with a more or less irregularly undulate margin. All of these species are more or less common in culti- vation in botanical gardens in Europe. FIG. 289. Curled dock (Rumex crispus) showing two of the lower, long-petioled, oblong- lanceolate and wavy-margined leaves, and a flowering branch, the upper leaves of which are narrowly-oblong and short-petioled. Rumex crispus or curled dock is a perennial herb growing in fields and waste places in the United States and parts of Canada. 524 A TEXT-BOOK OF BOTANY. FIG. 290. Field or sheep sorrel (Rumex acetosclla) , a common weed containing a sour juice and growing in open fields; i to 3 dm. high, having narrow-lanceolate or halberd- shaped leaves, and somewhat reddish flowers in a panicled raceme. — After Brown. The leaves are oblong-lanceolate, with an undulate margin and rather long petiole. The flowers have a 6-parted, dark green perianth, and are perfect or polygamo-dicecious. The fruit is a CLASSIFICATION OF ANGIOSPERMS. 525 dark brown, cordate-winged, 3-angled akene. The dried root is somewhat fusiform, reddish-brown, and with a bitter, astringent FIG. 291. Polygonum pennsylvanicum (Fam. Polygonaceas), one of about 30 species of knotweeds, being common in waste places, all herbaceous, and characterized by the leaves having sheathing stipules. Typical of this group is P. pennsylvanicum, having lanceolate leaves and short, erect terminal spikes with bright rose-colored flowers. — After Brown. taste. It contains chrysophanic acid, tannin, calcium oxalate, and some of the other constituents found in rhubarb (Fig. 289). Rumex Acetosella (field or sheep sorrel) is a slender annual herb with hastate leaves, having flowers in compound racemes. 526 A TEXT-BOOK OF BOTANY. The leaves contain oxalic acid, both free and in combination with calcium and potassium (Fig. 290). FIG. 292. Buckwheat (Fagopyrum esculentum) : A, transverse section of grain showing pericarp (c), endosperm (n) and slender coiled embryo (e) ; B, transverse section of portion of grain showing epicarp (e), fibrous layer (f), pigment layer (p), outer epidermis of spermo- derm (o), aleurone cells (a), endosperm cells containing starch (n) ; C, surface view of cells of epicarp; D, isolated fibers of pericarp; E. surface view of aleurone cells; F, isolated par- enchyma cells of endosperm filled with starch grains as seen in buckwheat flour; G, appear- ance of starch grains when mounted in oil and viewed with polarized light ^H, swollen and altered starch grains which are two to three times the size of the normal grains. Tannin is obtained from a number of the plants belonging to the Polygonacese, as the root of Rumcx hymenosepalus of Texas CLASSIFICATION OF ANGIOSPERMS. 5^7 which is known as CAXAIGRE; the rhizome of Polygonum bistorta of Europe which yields the drug BISTORTA. Polygonum cuspidatum of the gardens contains emodin ; poly- gonin, a glucoside yielding emodin ; and probably emodin methyl ether. Rumex ecklonianus of South Africa contains emodin, a volatile oil and a resin. The latter consists of emodin monomethyl ether; chrysophanic acid, physosterol (resembling rhamnol), etc. Polygonum ' Hydropiper and P. aviculare, both common in the United States, are poisonous to sheep. A number of the plants of this family yield food products. Buckwheat is the fruit of Fagopyrum csculentum indigenous to Central Asia and cultivated in many parts of the world ( Fig. 292). Some are also cultivated as ornamental plants, as the Prince's feather (Polygonum orientate). XI. ORDER CHENOPODIALES OR CENTROSPERM.E. This order includes seven families, in all of which the embryo is curved or coiled, and the reserve consists chiefly of perisperm. a. CHENOPODIACE^: OR GOOSEFOOT FAMILY.— The plants are annual or perennial herbs with simple leaves and small perfect flowers, the fruit being a utricle. The fruits of a number of the group contain volatile oil, and are used in medi- cine, as the common wormseed (Chenopodium ambrosioides anthelminticum) , which is found in waste places in the United States. Most of the oil is distilled in Maryland and is known in commerce as " Baltimore oil." Chenopodium mexicanum yields saponin. Atriplc.r liortensis of Tartary yields indigo. The ash of very many species of Atriple.v as well as genera of the Chenopodiacese yields soda. The seeds of several species are edible, as of Chenopodium I'iride of Europe and Asia, C. Quinoa of Chile, etc. Seeds of Spinacia tetandra of the Orient are used in bread-making. A number of species are used as garden vegetables, as spinach (Spinacia oleracea} and beet (Beta vulgaris). The SUGAR BEET (Beta vulgaris Rapa), which contains from 4 to 15 per cent, of cane sugar (sucrose), is largely cultivated in Germany, as well as to some extent in the United States, and is an important source of cane sugar. \Yhile the juice of the beet 528 A TEXT-BOOK OF BOTANY. contains a larger amount of nitrogenous substances than that of the sugar cane, it is practically free from invert sugar. b. AMARANTACE/E.--The plants are weed-like and much resemble the Chenopodiaceae. They yield anthelmintic principles, edible seeds, and the leaves of a number of species are used as vegetables. The ash yielded by some species contains potash, as Achyranthcs aspera and Amaranthus ruber. Some are ornamental plants having a fasciated inflorescence, as the Cock's-comb (Celosia cristata). c. NYCTAGINACE/E OR FOUR-O'CLOCK FAMILY.— The plants are mostly herbs growing in America. The leaves are entire and simple, and the flowers are regular and in terminal or axillary clusters. The perianth consists of a 4- to 5~lobed corolla- like calyx. The most common representative of this family is the Marvel-of-Peru or four-o'clock (Mirabilis Jalapa}. While this plant is an annual in the L'nited States, in the Tropics the tuberous root is used as a substitute for jalap, and is sometimes sold for it. The seeds of this plant are edible, as are also the leaves of several species, as of Bccrhavia crccta, which are used as green vegetables. Some members of the group, as Bougainville a spectabilis, are handsome plants with bright rose-colored bracts which envelop the small greenish flowers. d. PHYTOLACCACEyE.— The plants of this family are mostly tropical and are represented in this region by only one species, namely, the common poke (Phytolacca dccandra) , the root and fruit of which are used to some extent in medicine. This is a succulent, branching herb I to 4 M. high, having a large perennial root. The stem is hollow except for the thin, papery partitions. The leaves are simple, ovate-lanceolate, petiolate. The flowers are in racemes and characterized by having ten stamens. The fruit is a dark purple, juicy berry (Fig. 293). The roots of this species as well as others contain powerful drastic principles, as Pircunia littoralis and Anisonieria drastica of Chile. Phytolacca abyssinica contains saponin, and a red color- ing principle is found in the berries of Phytolacca decandra and Rivinia tinctoria of Venezuela. The leaves of some species of Phytolacca are used as greens. e. AIZOACEy£.--This is a group of mostly tropical plants, CLASSIFICATION OF ANGIOSPERMS. 529 FIG. 293. Poke weed (Phytolacca decandra), a common weed growing in low grounds and waste places. The plant is a perennial herb, usually sending up from a large, fleshy root a number of stout stalks, r to 3 M. high; the leaves are ovate-oblong, and opposite which may arise the. racemes of whitish flowers. The roots are quite frequently mistaken for parsnips, and when eaten may cause serious illness. The young shoots and leaves are sometimes gathered in the spring and may be used for a table vegetable. The juice of the berries is said to have been used in Portugal to color Port wine. — After Brown. very many of them having fleshy leaves and adapted to arid re- gions. Many of the plants, particularly those belonging to the genus Mesembryanthemum, are much prized on account of their 34 530 A TEXT-BOOK OF BOTANY. beautiful flowers, which expand only in the sunshine. The com- mon ice-plant of the gardens, so called because of the numerous glistening globules of water which cover the leaves, is M. crystal- FIG. 294. Soapwort, Bouncing Bet (Saponaria officinalis}, a perennial herb growing to a height of 3 to 6 dm. and producing opposite, entire leaves, and cymose clusters of rose- colored flowers, commonly double. This plant has been more or less cultivated; it has, however, escaped from the garden, and, in spite of its beauty, has become a troublesome weed in some places. The plant contains saponin and therefore forms a lather with water. It has been used as a detergent. — After Brown. Union. This plant as well as other species of Mesembryanthemum are used in medicine. The ashes yielded by the plants of this family also contain soda. The seeds of some species of Mesem- CLASSIFICATION OF ANGIOSPERMS. 531 bryanthemum as well as other members of this family are edible, and the leaves of some species are used as vegetables like lettuce. /. PORTULACACEyE.— The plants are fleshy or succulent herbs mostly indigenous to America. The two common represen- tatives are the spring beauty (Claytonia virginica), the tubers of which are rich in starch, and purslane (Portulaca oleracea) , some- times used as a green vegetable. The seeds of the latter plant as well as of other species of Portulaca are used in medicine. g. CARYOPHYLLACE^:.— The plants are annual or peren- nial herbs, often swollen at the nodes, with opposite, entire leaves, and usually perfect regular flowers. The perianth has a distinct corolla of 4 or 5 petals. The fruit is a capsule and the seeds are half anatropous. The plants are most abundant in the northern hemisphere ; and some of them are quite showy, as the CARNATION (Dianthus caryophyllus) and pinks (Dianthus species) and the cultivated pink or Sweet William (D. barbatus). A numb.er of the members of this group contain saponin, as Bouncing Bet (Saponaria oMcinalis), which is naturalized in the United States (Fig. 294), Gypsophila Struthium of Spain and other species of this genus, as well as species of Lychnis and Her- niaria. The leaves of Paronychia argentea are used in Morocco as a substitute for tea. The roots of Scleranthus pcren- nis of Eastern Europe are inhabited by an insect (Coccus polonica) which is used in the preparation of a red dye. The fleshy stitch-wort (Alsine crassifolia) of Europe and the United States is poisonous to horses. XII. ORDER RANALES. The plants are mostly herbs, but include some shrubs and trees, and comprise eight families of economic importance. a. NYMPH^ACE^E OR WATER LILY FAMILY.— These are aquatic perennial herbs with thick root-stocks and floating, peltate leaves. The flowers are perfect and have large petals. The seeds are enclosed in an aril, and the embryo has fleshy cotyledons. Nnphar hit cum of Europe and Middle Asia contains the alka- loid nupharine and tannin, the latter of which splits into ellagic and gallic acids. The yellow pond lily (Nymphara advena} of the 532 A TEXT-BOOK OF BOTANY. United States contains similar principles. The seeds and rhizomes are rich in starch and are used as food, in some cases starch being manufactured from them, as of various species of Xyiuphaca, Nelunibo (Lotus) and Victoria, and Euryalc fero.r. b. RANUNCULACEyE OR CROWFOOT FAMILY.— These are annual or perennial herbs with simple or compound leaves, regular or irregular flowers, and fruits which are akenes, follicles, or berries. FIG. 295. Fruiting top of Golden Seal (Hydrastis canadensis], showing the two large palmate leaves, above one of which is a berry-like fruit which is bright red when ripe. Hydrastis canadensis yields the official drug hydrastis. From a short, thick, horizontal rhizome with numerous slender roots rises a short stalk with a few palmately lobed, reniform, petiolate, pubescent leaves. The flowers are small, solitary and greenish- white, and the fruit is a head of crimson berries somewhat resem- bling the raspberry (Fig. 295). Cimicifuga ruccinosa (black cohosh or black snakeroot) yields the official drug cimicifuga. This is a tall perennial herb with large knotty rhizome, large decompound leaves, and a long raceme of white flowers (Fig. 296). CLASSIFICATION OF ANGIOSPERMS. 533 FIG. 296. A group of transplanted wild plants with a plant of Cimicifnga racemosa in the foreground, showing the characteristic, large, decompound leaves and long raceme of flowers. Acomtum Napcllus yields the official drug aconite (Fig. 186). This is a perennial herbaceous plant indigenous to Europe and extensively cultivated. From a tuberous root arises a simple leafy 534 A TEXT-BOOK OF BOTANY. stem with palmately lobed or divided leaves, and large, irregular, blue flowers which form a rather loose panicle (Fig. 297). The sepals are 5 in number, the posterior upper -one being large and E FIG. 297. Acomtum Napellus . A, one of the long-petiolate, divided leaves; B, epi- dermal cells of lower surface; c, an epidermal cell of the upper surface; D, transverse sec- tion through one of the principal veins showing two fibrovascular bundles, and strongly collenchymatic cells beneath the lower epidermis; E, one of the few hair? from the petiole; F, liuinified bast fibers surrounding the sieve in the petiole; G, longitudinal section through fibro vascular bundle showing spiral arfd reticulate tracheae (t), bast fibers (b) and some of the collenchyma cells (c), those at the left exhibiting longitudinal pores which give a crystal-like effect. helmet-shaped. The petals are 2 to 5 and rather small ; the two posterior or upper ones which are hooded and concealed in the helmet-shaped sepal are nectar-secreting (Fig. 223, E). The fruit is a follicle and contains numerous small seeds. CLASSIFICATION OF ANGIOSPERMS. 535 FIG. 298. Wood anemone, wind flower (Anemone qiiinque folia), one of the earliest flowering woodland plants. It is a low, slender plant with 3 trifoliate leaves forming an involucre, from the junction of which arises a peduncle, bearing a solitary flower. The sepals vary in number as well as in color; there are generally 5, which are usually whitish, or slightly tinged with purple. — After Brown. Delphinium Staphisagria which yields the official staphisagria or stavesacre, is a handsome, tall, biennial larkspur, with dark green, palmate 5- or /-lobed leaves and blue or purplish flowers in A TEXT-BOOK OF BOTANY. FIG. 299. Wild Columbine (Aquilegia canadensis}, one of the most interesting plants of the Ranunculaceae. It grows in the crevices of rocks and in open woods, and is a very striking plant, with its 5 long-spurred, scarlet petals. A number of species of Aquilegia are cultivated, and their flowers show considerable variation in form and color. — After Brown. racemes. The flowers are zygomorphic and somewhat resemble those of Aconite. CLASSIFICATION OF ANGIOSPERMS. 537 PULSATILLA, which was formerly official, is obtained from sev- eral species of Anemone growing in Europe. These are perennial herbs (Fig. 206) with basal leaves which are deeply lobed or dissected, those of the stem forming a kind of involucre near the flower. The flowers are rather large and with numerous petaloid sepals. The fruit is a densely woolly achene in those species which are used in medicine. The entire plant is used and contains an acrid volatile oil, the principal constituent of which is an anemone camphor (anemonol). The latter is easily decomposed into anemonon, which on fusion becomes exceedingly acrid. Similar principles are found in other species of Anemone as well as in certain species of Ranunculus (buttercup) and Clematis ritalba of Europe. Very many of the other Ranunculacese contain active princi- ples. The glucoside helleborein, which resembles digitalin in its medicinal properties, is found in Hellebores niger, the BLACK HELLEBORE of Europe, and probably in other species of Helleborus, as well as in Act oca s pic at a, the baneberry of Europe, and Adonis vernalis, the false hellebore of Europe and Asia. c. BERBERIDACE/E OR BARBERRY FAMILY.— The plants of this family are herbs or shrubs with simple or compound leaves, and flowers either single or in racemes (Figs. 134, E; 81, T). The fruit is a berry or capsule. Berberis Aqiiifolium (trailing mahonia) yields the unofficial drug berberis. It is a low, trailing shrub with 3- to 7-compound, scattered leaves. The leaflets vary from oval to nearly orbicular, are obtuse at the apex, slightly cordate at the base, finely reticulate, and spinose-dentate. The flowers are yellow and in dense ter- minal racemes. The fruit is a blue or purplish berry. Caulophyllum thalictroides or blue cohosh of the Eastern United States is a perennial herb with a thick rhizome and large ternately compound leaves (Fig. 300). The flowers are small and greenish-purple. The fruit is peculiar in that it resembles a berry and consists only of blue, globular, naked seeds, the pericarp being ruptured and falling away soon after fertilization. The rhizome and roots were formerly official. It is a horizontal, much branched rhizome with broad, concave stem-scars, and numerous roots ; it is grayish-brown externally, sweetish, slightly bitter and 538 A TEXT-BOOK OF BOTANY. somewhat acrid. The drug- contains an acrid, saponin-like gluco- side, leontin ; a crystalline alkaloid, caulophylline ; two resins ; and starch. For analysis of the seeds see Chem. Xcivs, 1908, p. 180. Podophyllum pcltatnin or May apple is the source of the official podophyllura. This is an early, herbaceous, low, perennial plant forming large patches by reason of its long dichotomously branch- FIG. 300. A group of transplanted plants, showing in the upper portion a fruiting plant of bine cohosh (Caulophyllum thalictroides) . ing rhizome (Fig. 182). It forms two kinds of branches, one bearing a single, peltate, 5- to 7-lobcd leaf; and another bearing in the axil of two similar leaves a white flowrer which gives rise to a large, yellowish, ovoid berry which is edible. d. MEXISPERMACE^ OR MOOXSEED FAMILY.— The plants are climbing1 or twining, herbaceous or woody vines with simple, entire or lobed leaves and small, greenish-white dioe- CLASSIFICATION OF ANGIOS PERMS. 539 cious flowers. The fruit is a drupe and contains a characteristic crescent-shaped seed. Menispermum canadcnse or Canada moonseed yields the drug menispermum which was formerly official. It grows in the North- ern United States and Canada and is a high-climbing vine with broadly ovate, cordate and 3- to 7-lobed leaves (Fig. 180). The flowers are in panicles giving rise to a characteristic cluster of bluish-black berries. The rhizome occurs in pieces which are 5 to 7 dm. long and 2 to 5 mm. in diameter ; externally it is longitudinally wrinkled, of a yellowish-brown color and somewhat resembles Sarsaparilla. In transverse section, however, it is very distinct (Fig. 194). The drug has a bitter taste and contains a bitter alkaloid menispine, berberine and starch. In addition it contains the alkaloid oxyacan- thine which is also found in Berberis vulgaris of Europe and the West Indies. Jateorliiza palmata yields the official drug calumba (columbo). The plant is a herbaceous climber somewhat resembling Meni- spermum, the leaves being more decidedly lobed. The flowers' form long racemes. Chondrodcndron toincntosnvi, the source of the unofficial drug pareira, is a high woody twiner. The leaves are large, petiolate, broadly ovate or rounded, slightly cordate, and densely tomentose on the lower surface. Anamirta paniculata is a woody climber of the East Indies. The fruits, known as fishberries or COCCULUS, are used as a fish poison by the natives and contain the neutral principle picrotoxin. Very many other plants of the Menispermacese contain power- ful toxic principles and are used as fish poisons and as antidotes to snake poison. Several species of Abuta are used in the prepara- tion of curare poison. e. MAGNOLIACE^E OR MAGNOLIA FAMILY.— The plants are mostly trees or shrubs and are represented in the United States by the magnolias and tulip tree (Liriodendron Tulipifera). The latter is a magnificent tree with characteristic leaves (Fig. 204) and large, fragrant, orange-colored, tulip-like flowers. The plants of this family contain a variety of constituents. 540 A TEXT-BOOK OF BOTANY. Ethereal oils containing anethol and resembling those of anise are found in the fruit of Illicium anisatum (I. verum) or STAR ANISE, a small evergreen tree growing in the mountains of South- ern China. A volatile oil with a disagreeable odor is found in a closely related species /. religiosuni (Shikimi) of Japan. The fruit of the latter plant is known as JAPANESE STAR ANISE and contains in addition a poisonous neutral principle. The fruits of both star anise (Illicium ) and the Japanese star anise are made up of 6 to 8 radially arranged follicles, which are dark brown, dehis- cent on the upper (ventral) surface and each contains a single, brown, shiny seed. Star anise has an odor and taste resembling anise. Japanese star anise has a bitter taste and in addition is brownish-black, very woody and strongly beaked. Volatile oils are also found in the flowers of the various species of Magnolia and in Michclia Champaca found in the Malay Archi- pelago and cultivated in India and Brazil, and in M. nilagirica of India, the latter being used in perfumery. Winter's bark is derived from Drimys Winteri, a shrub of South America. It occurs in quills which are from 5 to 10 mm. thick ; externally it is grayish-brown and covered with numerous lichens ; the fracture is short, the broken surface being marked by stone cells and resin canals ; the odor is fragrant ; taste aro- matic, pungent and bitter. The drug contains a volatile oil which consists essentially of a hydrocarbon known as winterin ; it also contains a resin. A crystalline principle magnolin, a glucoside and a volatile oil are found in Magnolia macrophylla (or cucumber-tree of the Southern States) and M. tripctala or umbrella tree growing southward from Pennsylvania. A bitter principle liriodendrin, a volatile oil, an alkaloid, and a glucoside are found in the tulip poplar or tulip tree. The bitter and aromatic bark of Michclia montana of Java is used like cascarilla ( Euphorbiaceae). A bitter resin is found in the fruit of Talauma Plumieri of the Antilles. A glucoside which dissolves the blood corpuscles is found in Talauma macrocarpa of Mexico. A red coloring principle soluble in water occurs in the leaves of Michclia Tsiampaca of Java. The fruits of Schisandra propinqua of Nepal and Kadsura Rox- CLASSIFICATION OF ANGIOSPERMS. 54i burghiana of Japan contain considerable mucilage and are edible. The latter plant is also used as a hair-restorer. From the ash of Schixandra chincnsis of China and Japan sodium chloride is obtained. The flowers of Magnolia Juglans are used to flavor tea and the FIG. 301. North American papaw (Asi;nit:a triloba}: A, branch showing lateral nodding flower and the large, pinnately- veined, entire leaves : B. section of the oblong, 3-seeded berry; C, D, seeds, the one in longitudinal section. — After Baillon. leaves of Talauma ovata are used as a substitute for tea in Brazil. /. ANONACE/E OR CUSTARD-APPLE FAMILY.— These are shrubs or small trees chiefly inhabiting warm-temperate and tropical regions. They yield very many economic products. The fruit of Xylopia brasilcnsis is used as a substitute for cubeb. Some yield fruits having an aroma similar to that of nutmeg, as 542 A TEXT-BOOK OF BOTANY. Monocarpia Blancoi of Africa and Jamaica. The flowers of Cananga odorata of tropical countries are used in the preparation of a pomade from which the perfume YLANG-YLANG is made. Ethereal oils are also found in other species, as Unona ligiilaris of Ambyona, the seeds of which are used in perfumery. The bark of Popowia pisocarpa of Java contains an alkaloid. FIG. 302. Nutmeg trees growing in Singapore. The trees are handsome, evergreen shrubs, extensively cultivated in the East Indies, and to some extent in tropical America.— Reproduced by permission of The Philadelphia Commercial Museum. The seeds of Xylopia salicifolia of Trinidad and A", muricata of Jamaica are very bitter, as are also the wood and bark of X. glabra of the West Indies. The seeds of Asiuiina triloba, the North American papaw (Fig. 301), contains an emetic principle. This plant should not be confounded with Carica Papaw- (Caricacese) which contains the ferment papain. Many of the Anonaceae yield large succulent fruits, some of which are edible, as the sugar apple obtained from Anoua squa- CLASSIFICATION OF ANGIOSPERMS. 543 mosa and CUSTARD APPLE from A. rcticidata both abundant in the Tropics. The fruit of A. niuricata sometimes weighs as much as two kilograms. g. MYRISTICACEJE OR NUTMEG FAMILY.— This family is represented by the single genus Myristica. Nutmeg FIG. 303. Young plant of Cinnamomum zeylanicum grown from cutting. (Fig. 302) and mace are obtained from Myristica fragrans, an evergreen tree with ovate, petiolate, coriaceous, entire and pinnately- veined leaves. The flowers are small, yellow and dioe- cious. The fruit is a berry having somewhat the shape and size of the green fruit of black walnut. It has a line of dehiscence, and when ripe is yellow. The arillode of the seed constitutes MACE, 544 A TEXT-BOOK OF BOTANY. while the kernel is th£ NUTMEG, the pericarp of the fruit and coat of the seed being rejected. h. LAURACE^E OR LAUREL FAMILY.— The members of this family are chiefly shrubs and trees which are distributed mostly in the Tropics, although a few are found in the temperate zones (Fig. 280, F). Sassafras officinale. — This is a tree common in the eastern and central portion of the United States and is characterized by its rough bark and its I- to 3-lobed leaves, from whence it received its former name Sassafras variifolium (Fig. 203). The flowers are yellow, dioecious and appear in the spring before the leaves. The fruit is an oblong, blue drupe. Cinnanwmum zcylanicum, which is the source of the Ceylon cinnamon (Fig. 304), is a small, handsome, evergreen tree with opposite, coriaceous, broadly lanceolate, 3- to 5~nerved leaves (Fig. 303). The flowers are yellowish-white, hermaphrodite, or both pistillate and staminate. The fruit is a black, ovoid berry. The oil of Ceylon cinnamon from the bark and branches is charac- terized by its content of cinnamic aldehyde ; from the leaves by eugenol ; and from the root bark by camphor. C. Cassia which yields Cassia cinnamon is a tree growing in China, Sumatra, and cultivated in Java. It has long, oblong-lanceolate leaves which are pubescent on the lower surface. Cassia cinnamon (bark) is also obtained from Cassia Burmanni. Saigon cinnamon (see Vol. II) is derived apparently from wild trees growing in the mountainous regions of Anam, the botanical origin of which has not been determined. The volatile oils of the members of the Lauraceae vary con- siderably in composition. In addition to the oils of Sassafras and Cinnamon the following may be mentioned: A CINNEOL- containing oil is found in Cinnamomum Olivcri of Australia, Umbellularia calif onrica of Western North America and Laitrus nobilis the noble laurel of the Mediterranean and Mexico. A J;OR- NEOL-containing oil is obtained from the root of Dicypellium caryophyllatum of Guiana, the wood of which is known in Cayenne as rose-wood. An oil containing a notable amount of METHYL SALICYLATE is obtained from the spice-bush (Lindera Benzoin] of the United States. CLASSIFICATION OF ANGIOSPERMS. 545 FIG. 304. Cutting cinnamon in Ceylon. Cinnamomum zeylanicum is a native of the forests of Ceylon and is extensively cultivated, not only on the western coast of that island but in other countries of tropical Asia. The manner of cultivation is such that a number of stems are allowed to grow from a single root. When of sufficient height these are cut down and the smaller branches removed, as shown in the illustration. The bark is then separated from the thicker portion of the stems, gathered into bundles and placed under mats until a slight fermentation takes place. After the corky layer is removed the product is ready for the market.— Reproduced by permission of The Philadelphia Commercial Museum. Cinnainomiim Camphora, or the camphor tree, is indigenous to China, Japan and Formosa, and is now cultivated in many warm 35 546 A TEXT-BOOK OF BOTANY. countries as a shade and ornamental tree, growing very well in Southern California and the Southeastern States. All parts of the tree contain a volatile oil which on oxidation yields camphor, which latter is obtained on distillation and sublimation. Camphor of poor quality is obtained from C. Parthenoxylon of Burmah, Malaya and China, and C. gland uliferum of the Himalayas. Cam- phor is also a constituent of other ethereal oils of this same family, as the Massoy bark oil obtained from the root bark of C. zeylanicum and C. Biinnanni of Java. A EUGEXOL-containing volatile oil is obtained from Ravemara, aroiuatica of Madagascar, and Machilus Thunbergii of Japan. Eugenol is also found in oil of laurel leaves (L. nobilis), Massoy bark oil, the oil of the leaves of Ceylon cinnamon, and the oils obtained from Cinnamomum Culilawan of the Malay Peninsula and China, and C. Wightii of East India, and possibly is also found in Dicypellium caryophyllatum. The wood and the bark of Nectandra or Beeberu (Nectandra Rodicci) of Guiana and Brazil contain several alkaloids, one of which is known as beeberine and is supposed to be identical with the alkaloids in Buxus sempervirens (Earn. Buxace^e) ; pelosine found in Pareira ; and paricine found in the bark of the cultivated cinchonas of Java. Coto bark, which is used in medicine, is obtained from an unknown tree in Northern Bolivia belonging to this family. The bark contains a volatile oil having a pungent taste, and a volatile alkaloid. Fatty oils are obtained from Ravensara aromatica of Mada- gascar, Lit sea glauca of Japan and other species of Litsea found growing in Cochin China and India. A red sap with a very fetid odor is obtained from Ocotea foctcns of tropical and sub-tropical America, and the stink-wood of South Africa (0. bullata). XIII. ORDER RHCEADALES OR PAPAVERALES. These are mostly herbaceous, seldom woody, plants. The flowers are perfect and the fruit capsular. This order includes two families of importance medicinally. a. PAPAVERACE/E OR POPPY FAMILY.— These are herbs with a milky or colored latex. Papaver somniferum or opium poppy is an annual herb I to 2 CLASSIFICATION OF ANGIOSPERMS. 547 M. high. The stem is sparingly branched, with alternate, deeply lobed, pubescent, clasping (by a cordate base), dull green leaves (Fig. 305, A). The flowers in the variety album, from which opium is obtained, are white or silver-gray, and in many cultivated varieties are large and extremely showy. The two sepals drop away with the expansion of the corolla ; the ovary is smooth, more or less globular and subtends the radiate stigma ; the fruit is a FIG. 305. A, Opium poppy (Papaver somnifsrum) ; B, California poppy (Esclis'-holt- zia calif ormca) showing flower (a), and capsules (b, c), one of which (c) is dehiscent. — After Schimper. capsule (Fig. 238), dehiscing by means of terminal pores, and contains a large number of extremely small white seeds, known as MAW-SEED, and which yield a fixed oil known as poppy-oil. The latex of this plant (Figs. 306, 307) yields opium. Other allied members of the Papaveraceas possess narcotic properties, but the alkaloid morphine has not been isolated from any of them, as the California poppy (EschscJwltzia calif ornica) (Fig. 305, B} : the Mexican poppy (Argcmonc jnc.ricana) ; Hy~ pecoum procumbenSj and Fiiuiaria plicata, both of Southern 548 A TEXT-BOOK OF BOTANY. Europe. These latter plants probably contain also the alkaloid protopine which is apparently identical with fumarine. Sanguinaria canadcnsis or bloodroot, the rhizome of which is official. The plant is a small, herbaceous, perennial herb with a red latex. The rhizome is horizontal, short and thick, and gives rise to a single, petiolate, palmately 5- to Q-lobed leaf and a single white flower with a long peduncle (Fig. 308). The capsule is 'FlG. 306. Poppy fields in the meadows 8 miles northwest of Ping-li, Shensi, China, showing the plants with large terminal flowers. — Reproduced by permission of The Phila- delphia Commercial Museum. oblong, 2-valved, and contains a number of smooth but crested seeds. Chelidonium ma jus (celandine) is the source of the herb CHELIDOXIUM which was formerly official. The plant is a delicate branching herb about 0.5 M. high ; with alternate, deeply pinnati- fid leaves ; yellow flowers ; slender elongated capsule resembling that of the mustards, and a yellow latex in every part. Celandine is indigenous to Europe and Asia and is common in waste places in the United States. The drug contains the following alkaloids : CLASSIFICATION OF ANGIOSPERMS. 549 FIG. 307. Poppy fields in Afionkarohissar, Turkish Empire. The capsules are ready to be incised allowing the milky juice to exude, which is then collected and constitutes the opium of commerce. — Reproduced by permission of The Philadelphia Commercial Museum. 550 A TEXT-BOOK OF BOTANY. Chelidonine (identical with stylophorine), chelerythrine (which is fluorescent ) . and protopine ( found also in opium and sangui- naria). It also contains a bitter neutral principle chelidoxanthin and several organic acids (Fig. 309). To this family belong a number of other plants which contain principles similar to or identical with those found in Sanguinaria and Chelidonium, and of these the following are common in the FIG. 308. A group of transplanted bloodroot plants (Sanguinaria canadensis) show- ing i-flowered scapes, and the palmately veined and lobed leaves'. United States: Yellow or celandine poppy (Stylo phonim diphyl- liun } and the Dutchman's breeches (Biciicnlla Cuciillaria). The alkaloid PKOTOPINE (fumarine) is found in the following plants of this family: Sanguinaria canadensis ; Chdidoniniu majus; Styloplwnun diphyllum; Eschscholtzia calif ornica; Glan- cium corniculatum of Middle Europe; Biciicnlla Cuciillaria; Ad- lumia fungpsa, the climbing fumitory of the United States and Canada; Fumaria officinalis, the fumitory of Europe, which is naturalized in the United States and Canada ; Bocconia cordata of China and Japan, and B. frutcsccns of the West Indies, Mexico CLASSIFICATION OF ANGIOSPERMS. 551 and Paraguay; Dicentra pusilla of Japan and several species of corydalis. The tubers of squirrel corn or corydalis (Bicuculla canadensis) contain the alkaloidal corydaline. FIG. 309. Celandine (Chelidonitim majus), a biennial herb, with pinnately divided leaves, and terminal clusters of small, yellow flowers. The plant has an orange-colored latex. — After Brown. b. CRUCIFER/E OR MUSTARD FAMILY.— These are herbaceous plants with characteristic flowers and fruits. The flowers have four deciduous sepals, four petals which are more or less spreading and clawed at the base, and six stamens which are tetradynamous (Fig. 280, B). The fruit is a 2-celled silique or 552 A TEXT-BOOK OF BOTANY. FIG. 310. Fruiting specimens of the two mustards, the one on the left White Mustard (Brassica alba), and the one on the right Black Mustard (Brassica nigra). — After Newcomb. CLASSIFICATION OF ANGIOSPERMS. 553 silicic, which varies in shape in the different genera (Fig. 310). Brassica alba (white mustard). — The plant is a slender, branching, more or less hispid (bristly hairy) annual or biennial herb usually less than 0.5 M. high, with deeply pinnatifid lower leaves and lanceolate, dentate upper leaves. The flowers are yellow, and the silique is densely hispid, constricted between the seeds and terminated by a long, flat, sword-like beak (Fig. 310). The seeds are official as white mustard (Sinapis alba) but are known in commerce as yellow mustard. Brassica nigra or black mustard, the seeds of which constitute the official black mustard (Sinapis nigra), is a larger, more branch- ing plant than Brassica alba, being from I to 3 M. high. The silique is erect, more cylindrical and with a slender, filiform beak (Fig. 310). Glucosides similar to those which occur in BRASSICA ALBA and BRASSICA NIGRA are also found in other species of BRASSICA, as well as in the following related' plants, but the oils produced are not identical: Horseradish (Roripa Annoracia), the oil being similar to volatile oil of mustard; water cress (R. Nasturtium) ; garden radish (Raphanus sativus) ; Sisymbrium Alliaria of Eu- rope, and the hedge mustard (S. officinalc) naturalized in the United States; TURNIP (Brassica Rapa) of Europe; field penny-cress (Thlaspi arvense) of Asia and found in waste places in the Eastern and Middle United States ; the narrow leaved pepper- grass (Lepidium ruderale) naturalized from Europe; scurvy-grass (Cochlearia officinalis) of Northern and Middle Europe, the herb of which, known as HERBA COCHLEARIA, is used in medicine ; 1 HONESTY' (Lunaria annua) common in cultivation on account of the ornamental use of the dry pods ; Parrya niacrocarpa of Southern Europe ; treacle mustard (Erysimum clicirantJioidcs) of Northern Europe and the United States, and garlic mustard (E. Alliaria). The seeds of most of the Cruciferse are also rich in fixed oils, and the commercial oils are obtained from the following species : Wild mustard or charlock (Brassica arvcnsis) naturalized in the United States from Europe ; Hesperis trist'is of Southern Europe ; cabbage (Brassica oleracea). An iNDico-forming glucoside is found in Isatis tinctoria of Europe and /. indigotica of China; 554 A TEXT-BOOK OF BOTANY. Neslia paniculate, of Europe and the Orient ; and Lepidium oivai- hicnse of the Hawaiian Islands. Shepherd's purse (Capsella Bursa-pastoris) contains an alkaloid (bursine) and tannin. The leaves and roots of many of the Cruciferae are used as garden vegetables, and some are cultivated as ornamental plants. The seeds of Lunaria biennis (or " honesty ") contain an orange-red crystalline alkaloid, or possibly a mixture of alkaloids. c. There are several other families of the Rhceadales which yield economic products. The RESEDACE.E include the migno- nette (Reseda odorata), the flowers oi which yield a fragrant vola- tile oil ; and R. Luteola of Europe, which contains a yellow coloring principle and also an anthelmintic principle. The MORINGACE.E comprise a single genus, Moringa. The root of M. olclfera of tropical and sub-tropical countries contains a volatile oil resem- bling the volatile oil of mustard, and the stem yields an astringent gum resembling that of Bombax malabaricum (Bombaceae). XIV. ORDER SARRACENIALES. This order includes several families which are of special inter- est because of the fact that the leaves are of peculiar construction and adapted to the catching and digestion of insects (Fig. 208). Probably all of the plants of this order produce proteolytic ferments resembling those in the pine-apple and are capable of acting upon and digesting animal substance. Some writers have supposed that the properties of these plants might be due to bac- teria present in the liquid contained in the pitchers of the leaves, but there seems to be no question that a distinct enzyme resem- bling trypsin is formed in those plants which have been studied. (a) The genus Sarracenia of the family SARRACENIACE/E or pitcher-plant family, is represented in the United States by a number of species. The rhizome of Sarracenia purpurea (Fig. 311) contains several alkaloids, one of which, sarracenine, seems to have some resemblance to veratrine. (b) The DROSERACEVE or sundew family includes the Droseras or sundew plants and Dioncea muscipula, the Venus's flytrap o^f North Carolina (Fig. 209). A number of species of Drosera contain a red coloring principle similar to that isolated from the rhizomes of D. IVhittakerii of Australia and is a derivative of methylnaphthoquinone. Citric CLASSIFICATION OF ANGIOSPERMS. 555 FIG. 311. Pitcher Plant (Sarracenia purpurea). The plant grows in peat bogs, and the pitcher-shaped leaves are usually half rilled with water and serve as a trap for insects, which are finally digested and furnish the plant with nitrogenous food. The flowers are single on a naked scape and of a deep purple color, the petals being arched over the style. Many species of Sarracenia are prized by horticulturists because of their odd trumpet- shaped leaves. — After Troth. acid has been found in D. longifolia, a sundew common in the United States as well as in Europe and Asia, (c) The family OOK OF BOTANY. FIG. 334. American Linden, Basswood or Lime tree (Tilia americanc.}. A, flowering branch showing the obliquely heart-shaped, serrate leaves with conspicuous midrib and primary veins, and cymose clusters of yellowish-white fragrant flowers, which are at- tached to the midvein of an oblong, leaf-like bract. B, several of the ovoid or spherical, nut-like fruits about the size of peas. — From Bulletin 26, U. S. Department of Agriculture. of Java. A yellow coloring principle is found in the leaves of Vallca cordifolia of Peru. A fatty oil is found in the seeds of several species of Elccocarpiis. A number of fruits of this family CLASSIFICATION OF ANGIOSPERMS. 609 are edible. Maqui Fruit is obtained from Aristotelia Maqui of Chile and is used to color wine. The seeds of Sloanca dcntata are eaten like chestnuts in Guiana. b. TILIACEyE OR LINDEN FAMILY.— The plants are shrubs or trees with alternate, simple leaves, and with white flowers in cymes or panicles. In the Linden or Basswood ( Tilia) the peduncles are partly adnate with the long, leaf-like bracts. The fruits are dry drupes (Fig. 334). The flowers of the European Linden (Tilia europcra] contain a fragrant volatile oil and are used in medicine. The flowers of other species of Tilia also contain volatile oils, and the flowers of Tilia tomentosa of Southern Europe are used to flavor champagne. The leaves of Tilia europcca contain the glucoside tiliacin. Sev- eral species of Grewia are used as fish poisons. A purgative principle is found in the seeds of Corchorus olitorius of Southern Asia, Africa and South America. A bitter principle occurs in the seeds of Corchorus t rid ens of Arabia, India and Egypt. A reddish-colored, fatty oil known as APEIBA OIL is obtained from the seeds of Apeiba Tibourbon of Guiana. The root of Greivia scabropliylla is used as a substitute for Althaea in India. Mucilage is found in the flowers and fruits of a number of genera. The leaves of Corchorus siliquosus are used in Panama as a substitute for tea. A number of the fruits of this family are edible, as of Muntingia and Apeiba. The bast fibers of several species of Cor- chorus, particularly C. capsularis of China and India, constitute jute, which is used in the making of cordage. The fiber is sep- arated by cold retting in stagnant water. c. MALVACEJE OR MALLOW FAMILY.— The plants are mostly herbs or shrubs with alternate, simple leaves, and regular, perfect, large flowers, with the stamens united into a column which encloses the styles (Fig. 222, E), and a capsular fruit. The culti- vated ornamental Hollyhock and Althaea belong to this family. Althrca officinalis or marshmallow is a perennial herb about i M. high with broadly ovate, petiolate, acute, dentate and lobed, pubescent leaves ; the flowers are 2 to 4 in number in the axils of the leaves and have rose-colored petals. The bractlets are linear and the fruit consists of 15 to 20 indehiscent carpels. The root is used in medicine as a demulcent. 39 6io A TEXT-BOOK OF BOTANY. GOSSYPIUM species.- -The plants are herbs or shrubs with 3- to 5-lobed leaves, and large axillary flowers ; the fruit is a 5-locular, dehiscent capsule or pod ; the seeds are spherical or somewhat angular and covered with long i-celled hairs, which, latter constitute cotton (Fig. 139). FIG. 335. Indian mallow, velvet leaf (Abutilon Theophrasti). A common plant grow- ing in waste places, with velvety, heart-shaped leaves; yellow flowers; and characteristic fruits, consisting of 12 to 15 beaked carpels. — After Brown. There are three important cultivated species. ( i ) SEA ISLAND COTTON is obtained from Gossypium barbadense, a plant which is principally cultivated in the Southern United States and also in Xorthern Africa, Brazil, Peru and Queensland. This species is distinguished by the fact that after removal of the hairs from CLASSIFICATION OF ANGIOSPERMS. 611 the seeds they are smooth. (2) G. arbor cum has purplish-red flowers, yields a particularly white cotton, and is cultivated in Egypt, Arabia and India. (3) G. hcrbaccuui is distinguished by its broadly lobed leaves and yellowish flowers. This plant has been cultivated for over 26 centuries in Arabia and the East Indies, and since 1774 in the United States. Of this latter species there are a number of cultivated varieties. The bark of the root constitutes the cotton-root bark of medicine. The seeds of the genus Gossypium contain a large percentage of fixed oil, which is obtained by expression and is official as COTTON SEED OIL. The residue is known as cotton seed oil-cake, and contains a considerable amount of proteins with a small quan- tity of oil and a poisonous principle, ricin. A fat resembling that of Cacao is obtained from the seeds of Pachira macrocarpa of Brazil ; Kapak oil is derived from the seeds of Eriodendron anfrac- tuosmn caribccum of the West Indies. The flowers of some of the members of the Malvaceae contain coloring principles, and have been used for dyeing, as Hollyhock (Althaa rosca) and Mallow (Malva sylvestris). MUSK SEED or Amber seed, which is used in perfumery as a substitute for musk, is obtained from Abelmos'chus inoschatus indigenous to the East .Indies and now cultivated in other tropical countries. Malva mos- chata also has the odor of musk, and is found in Middle and Southern Europe. Saponin is found in the roots of Sida jamaicensis and Hibiscus Sabdariffa of the East and West Indies ; Sida paniculata of Peru is used as an anthelmintic and the action is supposed to be due to the glandular hairs. The seeds of several members of this family are used as substitutes for coffee, as Abutilon muticum of Egypt, and Okra or Gumbo (Hibiscus esculeutiis) . The leaves of Sida canarieiisis and 6\ ret lisa, the latter of India, have been substituted for tea leaves. The fruits of several of the members' of this family are edible, as Hibiscus csculcntus, which yields the vegetable okra, and H. ficulneus of Ceylon and Egypt, which are used like beans. Fibers are obtained from a number of the other members of this family, as the bast fibers of Hibiscus tiliaccus of the Tropics, H. cannabiniis of the East Indies, I 'rcna lobata, Abutilon indicum, j5i2 A TEXT-BOOK OF BOTANY. Sida rctusa, and Xapcra Iccvis, all cultivated more or less in tropical countries. d. FAMILY BOMBACE.E.— This is a group of tropical trees yielding a variety of useful products. A gum is obtained from Bombax malabaricum, and mucilage is contained in the genus Ochroma and several species of Bombax. The root of Bombax malabaricum contains tannin in addition. The bast fibers of a number of the plants of this family are used like cotton in making fabrics, as species of Bombax, Chorisia and Adansonia. The fruits of several of the Bombaceae contain tartaric acid, as the Sour Cucumber tree or CREAM-OF-TARTAR TREE (Adansonia Greg- orii) of Northern Australia ; and the MONKEY-BREAD TREE or BAOBAB (Adansonia digitata) of India and South America, which attains a diameter of 9 M. The green fruit of Matisia cordata of the Andes region is edible. The seeds of Bombax insigne and Matisia Castano of South America yield a product on roasting which is used like cacao bean. The seeds of Cavanillcsia umbel- lata of Peru are edible and contain a considerable quantity of fixed oil. e. STERCULIACE^E OR COLA FAMILY.— The plants are herbs, shrubs or trees, sometimes lianes, with mostly simple, petiolate, alternate leaves ; the flowers are small and form a rather complex inflorescence. Theobroma Cacao is a small tree 5 to 10 M. high, with cori- aceous, glaucous, entire leaves, and clusters of brownish 5~mer- ous flowers arising from the older branches or stem ; the fruit is large, fleshy, ovoid, lo-furrowed longitudinally, yellow or reddish, and contains five rows of seeds, 10 or 12 in each row (Fig. 336). The seeds are ovoid, somewhat flattened, and with large, convo- luted cotyledons which break up into more or less angular frag- ments on drying. The seeds contain 35 to 50 per cent, of a fixed oil known as CACAO BUTTER and official as Oleum Theobromatis ; 15 per cent, of starch; 15 per cent, of proteins; I to 4 per cent, of theobromine ; 0.07 to 0.36 per cent, of caffeine, about 0.5 per cent, of sugar, and also a small amount of tannin. The red color of the seed is due to a principle known as cacao-red which is formed by the action of a ferment on a glucoside. The Cacao tree is indigenous to the countries bordering the Gulf of Mexico and is now cultivated in many tropical countries. CLASSIFICATION OF ANGIOSPERMS. 613 FIG. 336. Cacao tree (Theobroma Cacao), growing in Rio Hondo, Costa Rica. In the illustration is shown the peculiar habit of this tree in producing large, ovoid, fleshy fruits on the main axis or trunk, as well as on the older branches. When Cortez conquered Mexico he found the Aztecs using Cacao seeds to make a beverage; this was later introduced into Europe, previous to either coffee or tea. — Reproduced by permission of The Phila- delphia Commercial Museum. 614 A TEXT-BOOK OF BOTANY. FlG. 337. A flowering branch of the Kola nut tree (Cola acurninata), growing in Trini- dad. The leaves are obovate or lanceolate, acuminate, and in the axils are borne small clusters of purplish flowers. The tree is indigenous to Africa and is extensively cultivated in the West Indies and Brazil, in which countries it has become naturalized. — Reproduced by permission of The Philadelphia Commercial Museum. CLASSIFICATION OF ANGIOSPERMSi 615 Most of the cacao of the market is obtained from Ecuador (the Guayaquil variety being especially valued), Curasao, Mexico, Trinidad, and the Philippine Islands. The seeds of the wild plants contain a bitter principle, the quantity of which is found to be greatly reduced in the plants when under cultivation. The bitter principles in the raw product are more or less destroyed by the process of fermentation to which the seeds are subjected in preparing them for use, which at the same time develops the aroma. Cola acmninata is a tree with lanceolate or obovate, acuminate, entire, petiolate leaves. The flowers are purplish, unisexual, and in small axillary clusters, frequently arising from the old wood ; the fruit consists of five follicles, each containing 4 to 8 seeds. The seed is made up of two large, fleshy cotyledons. They have much the same constituents as Cacao, but the proportions of these differ (Fig. 337). The leaves of Waltheria glomerata are used as a hemostatic in Panama like matico, as are also the leaves of Pterospermum acerifolium. The inner bark of Fremontia calif onrica is used for purposes similar to those of elm bark. Mucilage is also found in the following genera: Pentapetes, Wal- theria, Guazmna, Helicteres, and Sterculia. Tannin is found in the bark of Guazwna ulniifolia of South America. An oil is manu- factured from the seeds of Sterculia fcctida of the East Indies and Cochin China. The seeds of a number of species of Sterculia are edible. Abroma angusta of India yields a fiber which has been suggested as a substitute for silk. XIX. ORDER PARIETALES. This is a group of plants of rather wide distribution, and includes perennial herbs like the violets ; evergreen shrubs, such as the Tea Plant ; and vines like the Passion flower. As the name indicates, the plants of this order are characterized by the flowers having, for the most part, ovaries with parietal placentas. a. FAMILY DILLENIACE^.— The plants are mostly trop- ical trees which yield valuable timber. The wood of a species of Dillenia growing in the East Indies also contains red coloring substances. The fruits of Dillenia indlca contain citric acid and are used like lemons. The leaves of Curatella americana contain considerable silicon and are used to polish wood. Dillenia speciosa 6i6 A TEXT-BOOK OF BOTANY FIG. 338. Leaves, flowers, and fruits of the Tea plant (Thea sinenis, or Camellia viridis). The plant is a shrub or small tree bearing lanceolate, evergreen leaves, and in the axils occur the rather large, white, fragrant flowers. The fruits are small, globular capsules. — Reproduced by permission of The Philadelphia Commercial Museum. of India contains a large percentage of tannin. Some species of Dillcma are cultivated and the foliage and flowers combine to make the plants the most beautiful in the plant kingdom. b. MARCGRAVIACE^:.— The members of this family are CLASSIFICATION OF ANGIOSPERMS. 617 partly epiphytic, and have dimorphic leaves, the smaller ones being pitcher-like. The plant which is cultivated in greenhouses, Marc- gravia umbcllata, is used in the Antilles in medicine. c. THEACE^: OR TEA FAMILY.— The plants are shrubs or trees with alternate, evergreen leaves, and perfect, regular FIG. 339- Picking tea on a plantation in Japan, the wall at the left probably being the ruins of an ancient temple. While the plant ordinarily is a shrub, it is kept trimmed and is a bush from 2 to 5 feet high. The plants begin to bear in the third year, and continue to yield a commercial article from 3 to 7 years thereafter. The number of crops per year is determined by the geographical location. In the tropical fields of Ceylon, India, and Japan leaves are picked frequently, while in northern Japan they secure only one crop a year. — Reproduced by permission of The Philadelphia Commercial Museum. flowers with numerous stamens, occurring one or more in the axils of the leaves. The fruit is a 3- to 5-locular, dehiscent capsule. The most important member of this family is Thca sinensis, the two varieties viridis and Bohca furnishing the leaves known as TEA. The Tea tree is indigenous to Eastern Asia, and is now extensively cultivated in China, Japan, India, Java, Brazil, Sicily, Portugal and France, and to some extent in the Southern LTnited States (Figs. 338, 339). 618 A TEXT-BOOK OF BOTANY. The fresh leaves of Thea do not have the properties which characterize the commercial article, the aroma and other qualities being developed after special treatment. Two general classes of tea are found in commerce, these depending on the mode of treat- ment. Those which are rapidly dried by means of artificial heat constitute GREEN TEA. The leaves which are slowly dried, per- mitting fermentation to set in, furnish BLACK TEA. Tea leaves contain 1.5 to 3.5 per cent, of caffeine; theobromine and the- ophylline (an isomer of theobromine) ; 10 to 20 per cent, of gallo- tannic acid ; quercitrin, and a volatile oil containing, among other components, methyl salicylate. The seeds contain about 30 per cent, of fixed oil, I per cent, of caffeine, and saponin. The leaves furnish one of the sources of the official caffeine. Saponin is found in the seeds of Thea Sasanqua of China and Japan. Two saponin-like substances (assamin and assaminic acid) are found in the seeds of Thea assamica. The flowers of T. Sasanqua are used in China and Japan to flavor teas. The flowers and leaves of Thea kissi are used as an insecticide. The red colored sap of Laplacea Hcematoxylon of New Granada is used in medicine. d. GUTTIFER/E OR GAMBOGE FAMILY.— The plants are principally shrubs and trees of the Tropics, that is, if we exclude the Hypericacese which are now put in a group by them- selves. Garcinia Hanburyi is a tree with ovate, petiolate, coriaceous, opposite leaves. The flowers are small, yellow, dioecious, occur- ring in small clusters in the axils of the leaves. The fruit is a pome-like berry, with a papery endocarp and an oily sarcocarp, and 3 or 4 seeds, i in each loculus (Fig. 340). The trees are chiefly valued on account of the gum-resin known as gamboge which they contain. A resin used in making plasters is obtained from Calophyllum brasilicnse of Brazil. Balsams resembling Copaiba have been obtained from Calophyllum Calaba of the West Indies. Balsams known as TACAAI AIIAC are also derived from the following plants : Bourbon Tacamahac from Calophyllum Tacainahaca, India Taca- mahac from C. apctalum and Brazilian Tacamahac from Rheedia Madnino. Balsams are also obtained from Caraipa grandiflora CLASSIFICATION OF ANGIOSPERMS. 619 of Brazil, and Rheedla acuminata of Peru. Resins and balsams are obtained from a number of species of Clusia. A yellow coloring principle, mangostin, is obtained from the bark and fruit of Mangosteen (Garcinia Mangostana) of the East Indies. Yellow coloring principles are found in Ochrocarpos FIG. 340. Gamboge plant (Garcinia Hanburyi). A branch showing the axillary pistillate flowers and pome-like fruits. — After Baillon. longifolius of India and Visinia aciuninata of South America. Tannin occurs in Mahurea paliistris of Brazil, Mesua fcrrca of the East Indies, that flower-buds of Ochrocarpos longifolius of India, and several species of Cratoxylum of China and Java. A butter-like fat is obtained from the seeds of Garcinia indica. A fixed oil known as LAUREL-NUT OIL is derived from the seeds of CalopJiyllum Inophyllmn and other species of Calophyllum 620 A TEXT-BOOK OF BOTAXY. growing in the East Indies, Cochin China and Brazil, as well as the seeds of Symphonia fasciculata of Brazil. The bark of Clusia pseudochina is used in Peru as a substi- tute for cinchona. An alkaloid is found in J'isinia robnsta of Java. A gum is obtained from Calophyllum touicntosiun of India and Vismia acuminata, that of the latter being purgative. The flower buds of the India Suringi (Ochrocarpos longifolius) have an aromatic odor resembling cloves. Aromatic principles are also found in other plants of this family. Edible fruits are yielded by the following plants : MANGO FRUIT from Garcinia Mangostana and other species of Garcinia; MAMMEI APPLE or Apricot of St. Domingo from Mainmea aiucr- icana of tropical America, the latter being used in the prepara- tion of Mammey wine or ' Toddy " and a liquor known as <( Eau de Creole." The seeds of Platonia insignis are used like almonds in Brazil and Paraguay ; the fruit of the latter plant is quite acid and is eaten with sugar. e. HYPERICACE;E OR ST. JOHN'S- WORT FAMILY.— The plants are herbs or shrubs of the temperate regions, and are represented in the United States by the Hypericums, which are quite common. The flowers are characterized by the numerous stamens which are united into distinct groups or clusters. The flowers of Hypericum perforatum or Common St. John's-wort contain yellow and red coloring principles. Yellow coloring prin- ciples have also been isolated from Hypericum laricifoliinn of Ecuador and H. elodcs of Northern Europe. The entire plant of H. perforatum is used in medicine and contains considerable resin, and a small amount of volatile oil. /. FAMILY DIPTEROCARPACE^E.— The plants of this family are principally trees and indigenous to tropical Asia. The family derives its name from the winged fruits of the principal genus Dipterocarpus. A number of economic products are fur- nished by this group of plants. BORNEO CAMPHOR is obtained from Dryobalanops aromatica. The camphor separates in canals in the older parts of the wood and between the wood and bark, and is obtained by felling the trees, splitting the wood, and then removing the camphor by hand. Owing to the fact that some of the trees do not contain camphor, it is sometimes necessary to fell CLASSIFICATION OF ANGIOSPERMS. 621 a hundred trees in order to obtain 6 or 8 K. of the product. The young twigs of this plant as well as the older wood yield a volatile oil known as Oil of Borneo camphor. GURJUN BALSAM or Wood oil is obtained from a number of species of Dipterocarpus growing in the East Indies by incising the stems as in the collection of turpentine. The balsam is used as a substitute for copaiba and contains an ethereal oil which consists chiefly of a sesquiterpene, an indifferent resin, and gur- junic acid. SINDOR BALSAM is obtained from Dipterocarpus inar- ginatus of Borneo. A resin known as ' : PINEY RESIN," which is used as a substitute for Dammar, is obtained from a number of species of Vateria growing in India. CHAIA RESIN is obtained from Shorea r-ubi folia of Cochin China. The bark of Shorea robusta of Northern India contains 32 per cent, of tannin. The seeds of species of Shorea, Pinanga, Gysbertsiana and Isoptera yield the fatty oil known in Java as TANGKAWANG. The seeds of a number of plants of this family contain considerable starch, as Vateria, Vatica and Doona. The woods of the following genera are extensively used : Vatica, Shorea, and Hopea. g. FAMILY TAMARICACE^E.— The plants are halophytic shrubs found in the desert regions of Central Asia and Mediter- ranean countries and one genus (Fouquieria) is found in Mexico. Fouquieria splendens is cultivated to some extent, and is known as Ocotilla or Coach-whip Cactus. The bark contains gum, resin and wax ; the latter is known as OCOTILLA WAX and resembles beeswax. The twigs of Myricaria germanica of Europe are used as a substitute for hops. A manna-like sugar is formed on the stems of Tdmarix niannifera growing in Egypt, Arabia and Afghanistan, as the result of the sting of an insect (Coccus nianni- parus). Tannin is found in a number of species of Tamarix as well as in the galls formed on the plants, the tannin being used for dyeing. A table salt is prepared from the ash of several species of Reaunmria found in Northern Africa and the East Mediterranean region. h. FAMILY BIXACE^E.— These are shrubs or trees found in the Tropics, and are of interest chiefly on account of the seeds of Bixa Orellana which furnish the coloring matter known as ANNATTO (Orlean, Arnotta). The plant is found in tropical 622 A TEXT-BOOK OF BOTANY. America and also in Polynesia and Madagascar. The seeds are covered with a fleshy arillus from which the coloring matter is prepared by means of water. The insoluble matter is collected, made into cakes and chiefly used for dyeing and coloring. Annatto contains a red crystalline principle, bixin, a yellow coloring prin- ciple, orellin, and an ethereal oil. The root of this plant also con- tains some coloring matter. A yellow coloring principle is found in Cochlospermum tinctorimn of Senegambia and an aromatic resin is obtained from Cochlospermum Gossypium of Ceylon and Malabar. i. FAMILY CANELLACE^; OR WINTERANACE/E.— These are trees with aromatic barks having an odor of cinnamon ; pellucid-punctate leaves ; and golden-yellow flowers. The most important member of this family is Winterania Canclla growing in the Antilles and in Southern Florida, which furnishes the CANELLA BARK or False Winter's bark used in medicine. The bark occurs in large quills or broken pieces, from 3 to 10 mm. thick, with the periderm nearly entirely removed, the outer surface yellowish or orange-red with transversely elongated patches of cork and shal- low, whitish depressions ; the fracture is short with numerous resin canals ; the odor aromatic ; taste aromatic, bitter and pungent. It contains mannitol, resin and 0.5 to 1.28 per cent, of a volatile oil containing eugenol, cineol, caryophyllene and pinene. The bark of one or more species of Cinnamodendron of tropical America is sometimes substituted for Canella bark, but it is distinguished by containing tannin, which constituent is not found in Canella. ;. VIOLACE^E OR VIOLET FAMILY.— The plants are herbs or shrubs with basal or alternate leaves, perfect, irregular flowers, and 3-valved dehiscent capsules (Fig. 280, /). The best .known representatives of this group are the cultivated species of the genus Viola, including the English or sweet violet ( Viola odor- ata), which produces a volatile oil containing ionon ; and the varie- ties of Viola tricolor vnlgaris which furnish the pansies of the garden. The entire herb of Viola tricolor has been used in medi- cine and contains the yellow coloring principle viola-quercitrin, salicylic acid and methyl salicylate (Figs. 201, 232). k. FAMILY FLACOURTIACE^. — These are tropical shrubs and trees, and are chiefly of interest because of their valu- able woods and acid, juicy fruits. A number of them are of CLASSIFICATION OF ANGIOSPERMS. 623 medicinal interest. CHAULMUGRA OIL is said to be obtained from the seeds of Gynocardia odorata of Farther India. The seeds also* contain gynocardic acid and hydrocyanic acid. The latter is also present in the seeds of Hydnocarpus venenata of Southern India and Ceylon and the leaves of Kiggelaria africana. A number of species of Lcctia growing in Cuba yield a resin resembling sandarac. The Coccos oil which is used in perfumery is obtained from several species of Myroxylon growing in Poly- nesia. The fixed oils from the seeds of Gynocardia odorata and of several species of Pangium are used in cooking. A bitter principle occurs in the bark of Casearia adstringens of Brazil. A purgative principle is found in C. esculenta of tropical Asia and Australia. The root of Homalium raccmosum of Guiana contains an astrin- gent principle. /. FAMILY TURNERACE^E— These plants are herbs, shrubs and trees mostly found in tropical America, and are of interest on account of the leaves of Tnniera diffusa, particularly the variety apkrodisiaca, which yield the DAMIANA of medicine, esteemed as a tonic laxative like Rhamnus Purshianus. The drug usually consists of leaves, although the reddish stems, yellowish flowers and globular capsules may be present. The leaves are about 25 mm. long, varying from oblanceolate to obovate ; the margin is serrate-dentate; the color, light-green (older leaves somewhat coriaceous and pubescent); the odor aromatic; taste aromatic and bitter. Damiana contains a volatile oil, resin, and the bitter principle damianin. Ethereal oils are found in other species of Turnera, and T. angustifolia of Mexico contains con- siderable mucilage. m. PASSIFLORACE^E OR PASSION-FLOWER FAM- ILY.— The plants are mostly herbaceous or woody vines climbing by means of tendrils, with alternate, palmately-lobed, petiolate leaves and solitary, perfect, regular flowers. The flowers are peculiar in that between the corolla and stamens there are numer- ous, frequently petaloid, colored, sterile, filamentous bodies which are known collectively as the " corona." The fruit is a berry or dehiscent capsule. The genus Passiflora is known as the Passion- flower because the flowers are considered to be emblematic of the Crucifixion, the corona representing the crown of thorns, the 624 A TEXT-BOOK OF BOTANY. stamens the nails, and the gynaecium with its three styles, the three thieves. The rhizomes of the Passion-flowers of the South- ern States (Passiflora incarnata and P. lute a} have been used in medicine. Xot much is known with regard to the active principles of these two plants or of the thirty other species of Passiflora which are used in medicine. The fruits of several species of Passi- flora are edible, and a number of them are cultivated on account of their beautiful as well as odorous flowers. n. CARICACE7E OR PAPAW FAMILY.— This family is composed of two genera of latex-containing trees growing in trop- ical America, the best known of which is the genus Carica. The Papaw or Melon tree (Carica Papaya} is a small tree with a straight, slender, usually unbranched trunk which bears at the summit a cluster of long-petiolate, deeply-lobed leaves. The flowers are dioecious, and the fruit is a large, melon-like berry. The green fruits as well as the leaves contain a milk-juice which is obtained by incising them. The material is dried and is used in medicine on account of its containing a proteolytic ferment, papain or papayotin, which is active in the presence of both acids and alkalies. The leaves and fruit also contain the alkaloid car- paine, and in addition the leaves contain the glucoside carposid. The root contains a glucoside somewhat resembling potassium myronate and a ferment which has a decomposing action upon it. A proteolytic ferment is also present in the leaves of Carica quer- cifolia of Argentina. The melon tree is cultivated on account of the fruits, which are edible. o. BEGONIACEyE.- -This is a family of tropical plants which are extensively cultivated. They are herbs or shrubs frequently with tuberous rhizomes and with characteristic, asymmetric, varie- gated leaves. They are easily propagated by cuttings, providing they have sufficient moisture, even the leaves giving rise to new plants. The roots of Begonia anenwnoidcs of South America and B. gracilis of Mexico contain purgative principles. Calcium oxal- ate and acid oxalates are found in the leaves of probably all of the species of Begonia. The roots of a number of species of this genus are astringent. />. DATISCACEyE.--The plants are trees or shrubs found principally in the Tropics. A bitter principle is found in the CLASSIFICATION OF ANGIOSPERMS. 625 Yellow hemp (Datisca cannabina) of Southern Europe and the Orient. The root contains a yellow coloring principle, datiscin, which is used in the dyeing of silk. The wood of Octomeles and Tetramelcs is used in the making of tea-chests. XXI. ORDER OPUNTIALES. The plants of this order are succulent, with much reduced leaves, and with flowers characterized by having a .perianth with numerous segments and an inferior ovary. a. CACTACE.E OR CACTUS FAMILY.— This is a remark- able family of succulent plants growing largely in the arid regions of Mexico, Brazil and other parts of America. The stems are more or less flattened, terete or tuberculated, in some cases becom- ing branched and woody. The leaves are reduced to scales, but are sometimes larger, more or less cylindrical or dorsiventral, and usually drop off sooner or later. In the axils of the leaves or leaf-scars there are usually groups of hairs and spines. The flowers are mostly solitary, sessile, perfect, regular and conspic- uous. The fruit is usually a fleshy berry, the fruits of a number of species being edible. Quite a number of the Cacti have been used in medicine, the one most commonly employed being the NIGHT-BLOOMING CEREUS (Cereiis grandiflorus), which is extensively cultivated on account of its flowers. The flowers and fresh stems are the parts used. They contain several acrid principles, including probably an alka- loid and a glucoside, the drug resembling in its action digitalis. MESCAL BUTTONS (Anhalonium) are the dried tops of several species of LophopJwra growing in Northern Mexico. The main axis of the plant is under the ground and produces at certain points small aerial shoots which are more or less button-shaped or disk-like, being about 20 to 50 mm. in diameter. In the center of the disk occur tufts of hairs which vary in the different species, and among which are usually found one or more pinkish flowers. The drug has been used like Night-blooming Cereus, and con- tains several alkaloids, namely, anhalonine (similar to pellotine), mescaline, anhalonidine and lophophorine. Alkaloidal principles are also found in other members of this family. The sap of several species of Cereus of the Antilles has anthel- 40 626 A TEXT-BOOK OF BOTANY. - FIG. 341. Prickly Pear or Indian Fig (Opuntia vulgaris}, a prostrate, more or less spreading cactus, composed of flattened stems bearing very small, awl-shaped and decidu- ous leaves and short, yellowish-green bristles and occasionally solitary spines. The flowers are pale yellow, opening in the sunshine. The fruit is a succulent berry about 2.5 cm. long. Various of these cacti are used as food by the cattle, which often eat them with the bristles. Frequently the spines are burnt off by the cattlemen with the use of gasolene torches, so as to prevent the accumulation of spines in the stomachs of the cattle in the form of phyto-bezoars, which are globular accumulations of vegetable tissues. (.See p. 577-)~ After Troth. CLASSIFICATION OF ANGIOSPERMS. 627 mintic properties, as also that of certain species of Rhipsalis and Opuntia. A caoutchouc-like exudation is obtained from Opuntia vulgaris and other species of Opuntia growing in the West Indies. An astringent principle is found in the root and bark of Opuntia Karwinskiana of Mexico. A tragacanth-like gum is found in Peireskia Guacamacho of Venezuela, Opuntia rubescens of Brazil and O. Tuna of the \Yest Indies, Mexico and South America. An alcoholic beverage is made by the Indians of Sonora from the fruit- juice of Ccrcns Thunbcrgii. A number of species of Opuntia yield edible fruits. The PRICKLY PEAR is the fruit of Opuntia Tuna growing in the \Yest Indies and tropical America; INDIAN FIG is derived from Opuntia Ficus-Indica growing in Southern Europe, particularly Sicily ; a fruit also known as Prickly pear or Indian fig is derived from Opuntia vulgaris, a common Cactus growing in sandy soil in the Eastern United States. The COCHINEAL INSECT which is official under the name of coccus in a number of pharmacopoeias (Coccus Cacti) feeds upon various of the Cactacecc, more especially the Xopal plant, Nopalca (Opuntia) coccinellifera, a native of Mex- ico and Peru. (See Kraemer, Amer. Jour. Pharm., 1913, p. 344.) XXII. ORDER MYRTALES OR MYRTIFLOR^. The plants are herbs or shrubs with complete flowers, rarely apetalous, producing one or more ovules in each loculus. a. THYMELyEACE/E OR MEZEREUM FAMILY.— The characters of this family are illustrated by the Spurge laurel or Mezereon (Daphne Mezereum), which is a small shrub about i M. high, with oblong-lanceolate, acute, entire, sessile leaves, and small groups of fragrant flowers, the perianth tube of which is purplish- red or white. The fruit is an ovoid, reddish drupe. The bark of Daphne Mezerewn and other species of Daphne is used in medicine. The bark of Funifera utills of Brazil contains a vesicating principle. A principle with similar properties is found in the bark of Leather wood (Dirca palitstris) of the Eastern L'nited States and Canada. The fruit and leaves of Gnidia carinata of Cape Colony contain emetic and drastic principles. A poisonous principle is found in Pimclea trichostachya of Australia. A 628 A TEXT-BOOK OF BOTANY. yellow coloring principle is found in several species of Daphne and Thymel&a. The wood of Aquilaria Agalloclia of India and China is aromatic and resembles the " Aloe wood." A balsam is obtained from the wood of Pimclea oleosa of Cochin China. The bast fibers of quite a number of plants are used in the making of paper, as of Daphne in India, Gnidia of Madagascar, Lagctta (L. lintearia or Lace-tree) of Jamaica and St. Domingo, Thvinelcca of the Mediterranean countries and Linodcndron of Cuba. The fibers of Leather wood (Dirca palnstris) of the Eastern L'nited States and Canada are said to be used in a similar manner. b. FAMILY EL^AGNACE/E.— This is a small family represented in the LTnited States by several genera, among which is the Buffalo berry (Lepargyrcca argcntea}, a thorny shrub found in the western part of the United States and the Northwest Terri- tory. The fruit is a reddish drupe-like berry which contains a small amount of citric and malic acids, 5 per cent, of sugar, and in composition is much like the currant. It is eaten by the Indians, and used to a great extent in the Western States in the making of jellies. The leaves and flowers of a number of species of El?eagnus are used in medicine. c. LYTHRACE^E OR LOOSESTRIFE FAMILY.— The members of this family are herbs, shrubs and trees usually with opposite, entire leaves. The flowers are in racemes and the fruit is a capsule. Quite a number of the plants yield valuable woods and a number are cultivated as ornamental plants. The flowers of Woodfordia noribiinda of India contain a red coloring principle, and the bark and leaves of Lafccnsia Pacari of Brazil contain a yellow coloring principle. Considerable tannin is found in the root of the Purple loosestrife (Lythrum Salicaria) of the Northern United States and Canada, and widely distrib- uted in the Old World ; and also in the fruit of Woodfordia flori- bunda, a plant which is extensively cultivated in greenhouses. A bitter principle, nessin, is found in the leaves of Nesa-a syphilitica of Mexico and probably other species of this genus. CupJiea z'iscosissiiiia of Mexico is said to resemble digitalis in its physiologi- cal action. A vesicating principle, resembling cantharidin in its action, is obtained from the fresh leaves of Ammannia baccifera of India. A narcotic principle is found in the seeds of Lager- CLASSIFICATION OF ANGIOSPERMS. 629 strccinia Flos-rcgincc of India. The flowers of Laii'sonia inermis, native to and cultivated in the Orient, have an odor resembling that of the Tea rose. The shrub is also cultivated to some extent in the West Indies and is known in the Orient as the HEXXA PLANT. The leaves are used in the preparation of the cosmetic Hinna. They contain an orange or brownish-yellow dye which is used in the dyeing of the skin and hair. d. PUNICACE^E OR POMEGRANATE FAMILY includes a single genus of two species. The Pomegranate (Punica gr ana- turn) indigenous to the Levant and now extensively cultivated is of chief interest. The plants are small trees, the young twigs of which are 4-angled and frequently thorn-like. The leaves are opposite, ovate-lanceolate, entire and short-petiolate. The torus, calyx and corolla are scarlet, and the gynsecium consists of two whorls of carpels. The fruit is an inferior edible berry with a hard pericarp or rind. The pulpy portion is formed from the outer layer of the seed-coat. The bark of the root and stem is used in medicine (see Granatum, Vol. II). The rind of the fruit is used as an astringent because of the tannin which it contains. It does not appear, however, to contain the alkaloids found in the official bark. e. FAMILY LECYTHIDACE^E.— The plants are mostly shrubs and trees indigenous to the Tropics. They are of chief interest on account of the BRAZIL-NUT (Fig. 342) obtained from Bertholletia excclsa, and the Sapucaya-nut obtained from the Monkey-pot tree (one or more species of Lecythis), both genera of South America. The seeds (so-called nuts) are rich in oil and proteins and are edible. The fruit of Careya arborea is drupa- ceous and is also edible, the seeds being considered, however, to be poisonous. Bitter narcotic or poisonous principles are also found in the fruit of Planchonia valida of the Molucca Islands and the seeds of a number of species of Lecythis. The fruits and roots of a number of species of Barringtonia are used in China and Java to stupefy fish. The pericarp of the fruit of Fcctida moschata of Guiana contains considerable quantities of an ethereal oil. The flowers of Grias cauliflora of the Antilles are used like tea. A cooling drink is made from the sarcocarp of Couroupita guianensis of the West Indies and Guiana 630 A TEXT-BOOK OF BOTANY, /. RHIZOPHORACE^ OR MANGROVE FAMILY.— These are tropical shrubs or small trees with evergreen, cori- aceous leaves, small cymose and axillary flowers, and seeds which germinate while the fruit is still attached to the plant. The best FIG. 342. Brazil-nut (also known as Para nut, cream nut, and nigger-toe), the seeds of Bertholletia excelsa, a Brazilian tree belonging to the Fam. Myrtaceas. In the illustration is shown a portion of the fruiting branch with some of the long, leathery leaves. The fruits terminating the branches are woody, vary from 10 to 15 cm. in diameter, and are in the nature of a pyxis, — i.e., opening by means of a lid. It encloses about 20 brownish-gray, 3-sided seeds, which are largely exported from Para. — Reproduced by permission of The Philadelphia Commercial Museum. known genus of this family is Rhizophora (Mangrove tree), of which there are three species, the AMERICAN MANGROVE being R. Maut/lc. This tree produces aerial roots on the stems and branches, and leaves which are characterized by a number of layers of CLASSIFICATION OF ANGIOSPERMS. 631 water-containing cells. The plants grow in muddy swamps, or along the sea-coast where the water is brackish, a number together forming the so-called " Mangrove swamps ' (Fig. 165). The root and bark of the Mangrove, as well as other species of Rhizophora and several species of Bruguiera, contain a large quantity of tannin which resembles catechu. The aerial roots of Rhizophora are used by the natives of Polynesia in the making of bows, and the woods of several genera are used in carpentry. g. MYRTACE/E OR MYRTLE FAMILY.— This is a group chiefly of shrubs and trees, some, as of species of Eucalyptus, being the loftiest trees known, attaining a height in some instances of 105 M. The plants are indigenous to Australia and tropical America and some are extensively cultivated. EUCALYPTUS species. — The leaves frequently vary in shape and in arrangement on the young and older branches of the same plant. On the young branches they may be, as in Eucalyptus Globulus, ovate or broadly elliptical, opposite and sessile, while on older branches they are scythe-shaped, glandular-punctate, glabrous, petiolate and alternate. In the latter case the petioles are twisted and the leaves stand edgewise so that both surfaces are equally exposed to the light and hence of similar structure. The flowers are solitary, or in cymes or umbels, occurring in the axils of the leaves. Petals are wanting and the whitish stamens, which are numerous and inflexed in the bud, are covered by an oper- culum or lid which is considered to be formed by the union of the sepals, and which dehisces on the maturing of the stamens, this being one of the most characteristic features of the genus. The fruit is a 3- to 6-locular truncated capsule or pyxis. This is a very important genus from an economic point of view, among the products being the volatile oil (oil of eucalyptus), and eucalyptol, both of which are official, and the tannin or so-called "gum," known as Eucalyptus kino. Jambosa Caryophyllus (Eugenia cary'ophyllata) .- -This is a small tree indigenous to the Molucca Islands and now extensively cultivated in the Tropics. The leaves are opposite, ovate-lance- olate, acuminate, petiolate, entire and evergreen. The flowers are rose-colored and in cymes ; the fruit is berry-like and constitutes the Anthophylli or MOTHER-CLOVE. The unexpanded flower-buds 632 A TEXT-BOOK OF BOTANY. constitute the drug or spice known as Cloves. (See Vol. II.) Pimento, officinalis is a tree with opposite, lanceolate, acute, petiolate, pellucid-punctate and evergreen leaves. The flowers are small, white and in axillary racemes. The fruit, known as " All- spice," is used for flavoring. Not only are ethereal oils obtained from the genera Euca- lyptus, Jambosa and Pimenta already described, but also from other members of the Myrtacese. OIL OF BAY or oil of Myrcia is distilled from the leaves of Pimenta acris of the West Indies. The oil consists largely of eugenol, methyl-eugenol, chavicol, methyl-chavicol, citral, phellandrene and myrcene, and is used in the preparation of BAY RUM. The fruits of P, acris yield 3.3 per cent, of an oil resembling the leaf oil. Cheken leaves are obtained from Eugenia Chekan. They are about 25 mm. long, ovate or rectangular, with entire, somewhat revolute margin, light green, pellucid-punctate, aromatic, astrin- gent and bitter. Cheken leaves yield about i per cent, of a volatile oil containing cineol and pinene ; 4 per cent, of tannin ; a volatile alkaloid and a glucoside. Oil of Cajeput is obtained from the leaves and twigs of Mela- leuca Leucadendron, particularly the varieties Cajeputi and minor of the East Indies. The principal constituents of this oil are cineol, terpineol, pinene, and a number of aldehydes and acid esters. An oil resembling Cajeput oil is obtained from the leaves and flowers of Myrceugenia camphorata of Chile. The leaves of Myrtus communis, a plant extensively cultivated in the Mediterranean countries of Europe, yield a distillate with water known as EAU D'ANGE and used as a toilet article. The leaves of the following plants are used as substitutes for tea leaves : Myrtus Molina of Chile, Mclaleiica gcnistifolia of Australia, and Leptospermum scoparium and other species of this genus growing in New Zealand. The seeds of Eugenia disticlia are known in the Antilles as Wild coffee. Quite a number of the genera of this family yield edible fruits. GL*AVA or Guayava fruit is obtained from Psidimn Guajava of tropical America. ROSE APPLE is the fruit of Jambosa malaccensis, growing in the East Indies and Oceanica. JAMP.TSE P.ERRIES are derived from Jambosa vulgaris which is extensively cultivated in the Tropics. The CLASSIFICATION OF ANGIOSPERMS. 633 lemon-like fruit of Myrcia coriacea is used in medicine, the bark in tanning, and the wood in dyeing. The fibrous bark of Eugenia ligustrina is used like oakum. h. FAMILY COMBRETACE/E.— The members of this fam- ily are shrubs or trees, sometimes climbing; with usually alternate, petiolate, simple leaves ; sessile flowers in racemes ; somewhat fleshy, winged, I -seeded fruits, and are mostly found in the Tropics. Like the Fagaceae the plants of this family contain a tannin, similar to gallotannic acid, in nearly all parts of the plant. The MYROBALANS of the East Indies are the young fruits of Terminalia Chebula. The pericarp, contains from 5 to 45 per cent, of tannin, the latter amount being found in the fruits known as Long or Chebula Myrobalans. The fruits also contain ellagic and chebu- linic acids. The fruits of Terminalia Bcllcrica constitute the Bel- eric Myrobalans. The galls of Terminalia macro ptcra of Africa and other species of Terminalia as well as of Bucida Buccras of tropical America are particularly rich in tannin. A yellow coloring principle is found in Terminalia Broivnii of Africa and is used in dyeing leather. The bark of T. Catappa of Asia and Africa is used to dye leather black. A gum-resin with cathartic properties is obtained from Termi- nalia fagi folia of Brazil. An aromatic resin is found in Ter- minalia angiistifolia of the East Indies. The fruits of one or more of the Combretaceae are said to be used in the preparation of the arrow-poison of the Negritos. The seeds of Terminalia Catappa and Combretum butyrosum contain about 50 per cent, of fixed oil. These seeds as well as those of other species of Terminalia and Quisqualis indica of Farther India and tropical Africa are edible. The seeds of the latter plant when unripe are said to be used like mustard. The woods of a number of the plants of the Combretaceae are valuable for building purposes, and some of the genera furnish ornamental plants which are cultivated in greenhouses. i. FAMILY MELASTOMATACE;E.— This is a large family of herbs, shrubs, and trees with opposite, 3- to Q-nerved leaves and regular, perfect, often showy flowers. They are chiefly found in South America and are represented in temperate regions by 634 A TEXT-BOOK OF -BOTANY the Meadow beauty (Rhexia). Quite a number of the plants are cultivated and a large number yield edible fruits. The fruits, barks and leaves frequently contain COLORING PRINCIPLES. A yel- low coloring principle is found in the leaves of a number of species of Memecylon of the East Indies and Africa, which resembles that of saffron and curcuma. Red coloring principles are found in the berries of a number of species of Blakea of South America. A black coloring principle is obtained from the fruit of several species of Tamonea of tropical America, Melastoma malabathri- cum of the East Indies and Tococa guianensis of Northern South America and Tibouchina Maxvmiliana of Brazil. Tannin is found in considerable quantity in the barks of Tibouchina, Dissotis and Rhynchanthera. The leaves of Tamonea thecczans are used in Peru as a Sub- stitute for tea. A mucilage is found in the bark of Medinilla crispata of the Molucca Islands. The flowers of the latter plant as well as of M. macrocarpa are used as a remedy for the bite of poisonous serpents. /. ONAGRACE/E OR EVENING PRIMROSE FAMILY. — These are mostly annual or perennial herbs with usually entire or toothed, simple leaves. The flowers are perfect, regular or irregular, epigynous, variously colored, solitary in the axils of the leaves or in somewhat leafy spikes. The fruit is a dehiscent capsule, berry, drupe, or nut. This family is represented in tem- perate regions by such plants as the Willow herb (Epilobium), Evening primrose (CEnothera), on which de Vries has carried on his famous mutation experiments, and Enchanter's nightshade (Circaea). The cultivated FUCHSIA also belongs to this family. A yellow coloring principle is obtained from the herb and unripe fruits of Jiissicua pilosa of Brazil. The roots of CEnothera bien- nns, O. muricata and other species of this genus are edible. This family also includes the group of aquatic plants, repre- sented by a single genus and one of which, Trapa natans or Water chestnut, is naturalized to some extent in the ponds of Massachu- setts and New York. The fruit is coriaceous, 2- to 4-spinose, and i -seeded. The cotyledons are unequal, rich in starch, and are edible, sometimes being ground and made into bread by the people of Europe and Northern Asia. CLASSIFICATION OF ANGIOSPERMS. 635 FIG. 343. Evening Primrose (CEnothera biennis), a simple, sometimes more or less branching herb growing to a height of 3 to 15 dm. The leaves are lanceolate or oblong- lanceolate; the flowers are symmetrical, with yellow petals; and the capsules are narrow and 4-valved. This plant is one of the commonest of the CEnotheras, growing in open places. It is a biennial like the other species, but it is possible for horticulturists to develop its life history in one year. — After Brown. 636 A TEXT-BOOK OF BOTANY. XXIII. ORDER UMBELLALES OR UMBELLIFLOR.E. The plants of this order are widely distributed in northern temperate regions, although there are some representatives in the Tropics. The flowers are small, 4- or 5-merous and epigynous. a. ARALIACE.^ OR GINSENG FAMILY.— The plants are mostly trees or shrubs with alternate, petiolate, simple or 3- to 7-compound leaves. The flowers are either in umbels or panicles. The fruit is a drupe or berry. The best known representatives of this family are the English ivy (Hedera Helix) of Europe, and Ginseng (Panax quinque folium) (Fig. 345) growing in the East- ern and Central United States. This plant is the source of the ginseng root of commerce, considerable quantities of which are exported to China, where it is used like the root of Panax Ginseng, a plant growing wild in Manchuria and Korea. Both plants are also cultivated in the United States, the roots from the wild plants being preferred. The root contains a volatile oil, and considerable starch. Several species of Aralia are used in medicine (Fig. 344). The leaves of the English ivy contain the glucoside helixin, and a carbohydrate, inosit. They also contain formic, oxalic, malic, tannic and hederic acids, besides the yellow principle carotin. The fruits of the ivy contain a purplish-red coloring substance and are said to be poisonous. The Chinese RICE PAPER is made from the pith of Tetrapanax papyriferum, which grows wild in Formosa and is extensively cultivated in China. The pith is cut spirally into thin strips, which are spread out flat and then cut into pieces varying from 15 to 30 cm. long and 10 to 12 cm. broad. This paper differs from other papers in that it is a natural product. The rhizome of Panax re pens, growing in Japan, contains 20.8 per cent, of a non-toxic saponin with hemolytic properties. b. UMBELLIFER/E OR CARROT FAMILY.— The plants are herbs, frequently with hollow stems ; alternate, simple or com- pound leaves, the base of the petiole often forming an inflated sheath ; and small white, yellowish, greenish or somewhat purplish flowers occurring in simple or compound umbels. The fruit is a cremocarp, having characters which are of important taxonomic CLASSIFICATION OF ANGIOSPERMS. 637 value, as the presence or absence of secondary ribs, number and position of the vittae, etc. FIG. 344. Wild Sarsaparilla (Aralia nudicaulis} . The plant produces a long, cylin- drical rhizome at or near the surface of the ground, and sends out at various points a single, long-stalked compound leaf, and a shorter, naked scape bearing 2 to 7 umbels of greenish- white flowers. The rhizome is sold as American Sarsaparilla, but it has none of the con- stituents of the true Sarsaparilla. — After Brown. Coriandrum sativum is an annual herb the fruits of which are official. The compound leaves are bi- or tri-pinnate, the leaflets 638 A TEXT-BOOK OF BOTANY. being narrow linear-lanceolate ; and the flowers are white or rose- colored. FIG. 345. Panax quinquefolium (Ginseng): A, upper portion of plant showing pal- mately-compound leaves with long-stalked leaflets and the berry-like drupes; B, fusiform root; C, roots showing characteristic stem scars at the upper portion. — From a photograph by Wyss. (See also Fig. 166, p. 305.) Conimn maculatum or Poison Hemlock is a tall, erect, branch- ing, biennial plant, with purplish spotted stems, large pinnately CLASSIFICATION OF ANGIOSPERMS. 639 decompound leaves and small, white flowers (Figs. 346, 347). The fruit as well as the leaves is used in medicine. Carum Carvi (Caraway) is a biennial herb with bi- or tri- pinnate, deeply incised leaves, and white flowers. The fruit is official and the leaves are also used in medicine. Pimpinella Anisum is a small, hairy, annual herb. The leaves are variable, the lower being somewhat cordate and serrate, the middle distinctly lobed, and the upper ones trifid ; the flowers are white. The fruit is official and is also used for flavoring. Fccniculum vulgar e is an annual or perennial, glabrous herb with very finely dissected leaves, the divisions being narrow-linear. The flowers are yellow, and the involucre and involucels are wanting. The fruit is official. Ferula fcetida is a stout, perennial herb with few, ternately compound leaves and small, polygamous, light yellow flowers. The root is rather large and yields the gum-resin asaf etida. Asafetida is also derived from other species of Ferula. Ferula Sumbul is a tall perennial herb with purplish latex- containing stems. The basal leaves are ternately compound and with amplexicaul base. The leaves decrease in size from the base upward, becoming bract-like near the inflorescence. The flowers are polygamous, resembling those of F. fcctida. The root is official and is probably also obtained from other closely related species of Ferula. A large number of the plants belonging to the Umbelli ferae contain essential oils, resins, gum-resins and related substances. The gum-resin AMMONIAC is an exudation found on the stem and branches of Dorema Ammoniacum and other species of Dorema as a result of the sting of an insect. The plant is found in Western Asia. The gum-resin occurs in yellowish-brown, globular, or somewhat flattened tears which are brittle, milky-white internally, with a distinct balsamic odor and bitter, acrid, nauseous taste. It contains a small quantity of volatile oil having the odor of Angelica. AFRICAN AMMONIAC is obtained from Ferula tingitana growing in Northern Africa and Western Asia. The gum- resin GALBANUM is obtained by incising the root of Ferula galbaniflua and other species of Ferula growing in the Levant. Galbanum occurs in pale yellowish-brown agglutinated 640 A TEXT-BOOK OF BOTANY. > TV *i FIG. 346. — Poison Hemlock (Conium maculatum}. showing the spreading habit of the plant and the prominent large compound umbels of flowers. — After Bornemann. CLASSIFICATION OF ANGIOSPERMS. 641 *•¥*• IKw^tt vis '*''• . • S,\«X^jfe 'v'lfe ^ d -»s^ .-Vt' x. FIG. 347. Conium maculatum, showing the large decompound leaves with pinnatifid leaflets, and the compound umbels of flowers, with detached, enlarged views of umbels and a compound umbel. — From Bulletin No. 26, U. S. Department of Agriculture. The fresh juice of Conium maculalum was used in the preparation of the famous hemlock potion which was employed by the Greeks in putting their criminals to death. This is not the same plant under the name of Conium which is referred to in Roman and mediaeval Latin literature, the latter being Cicuta virosa, which does not grow in Greece and in Southern Europe. 642 A TEXT-BOOK OF BOTANY. St. FIG. 348. Cicuta maculata (Water Hemlock): A, upper part of stem with leaves and compound umbels; B, base of the stem and the thick tuberous roots; C, cross-section of stem showing part of a mestome-strand and the pith with secretory cells (a), vessels (v), libriform (St), pith (p) ; D, a flower showing petals with long inflexed summit and the five stamens inserted on the disk that crowns the ovary; E, the fruit; F, fruit in longitudinal section showing the two ovules; G, cross-section of a mericarp showing the six vittae or oil- tubes. — After Holm. tears, forming a more or less hard mass, which is brittle when cold but soft and sticky at 37° C. ; the odor is distinct, balsamic; the taste bitter and acrid. It contains from 10 to 20 per cent, of a volatile oil composed of d-pinene, cadinene, and other principles. CLASSIFICATION OF ANGIOSPERMS, 643 A volatile oil, known as AJOWAN OIL, and containing thymol, is obtained from the fruit of Carum Ajozvan of Europe, Asia and Africa. A volatile oil containing APIOL is found in the fruit and leaves of the garden parsley (Petroselinum satii'iun). DILL OIL is obtained from the garden Dill (Anethum gravcolens). The fruit of Sweet cicely (Washingtonia longistylis) yields a volatile oil known as sweet anise oil, which contains anethol. The oil of water fennel (CEnanthe Phellandrium) contains about 80 per cent, of phellandrene. CUMIN OIL is obtained from Cuminnm Cyminum of Turkestan and Egypt, and contains cymene. The roots of a number of the plants of this family contain volatile oils, as Lovage (Levisticum officinale) of Southern Europe; European angelica or garden angelica (Angelica Arch- angelica) ; American angelica or the purple-stemmed angelica (A. atropurpurea) found in the Northern and Eastern United States and Canada; Wild angelica (A. sylvestris) of Europe. c. CORNACE/E OR DOGWOOD "FAMILY.— The plants are shrubs or trees with simple, opposite leaves, and flowers in cymes or heads, which in the case of the Flowering dogwood (Cornus florida) are subtended by four large, petal-like, white, or pinkish bracts. The fruit is a I- or 2-seeded drupe. The bark of Cornus Honda, a shrub or small tree growing in the United States, contains a bitter principle, cornin ; and a small quantity of gallic and tannic acids. Aucuba japonica, a plant indigenous to the Himalayas, China and Japan and extensively cultivated on account of its crimson berries, contains a glucoside aucubin. It is found in the different varieties and varies in amount from 0.31 to 1.96 per cent. METACHLAMYDE.E OR SYMPETAL^E. This is the highest group of plants and is marked by the follow- ing characters : The corolla is sympetalous ; the flowers are mostly perigynous or epigynous and both the corolla and stamens are borne on the perianth tube. The number of parts is definite, there being 5 sepals, 5 petals, 5 or 10 stamens and 2 or 5 carpels. This sub-class includes but six orders, to which, however, belong a large number of medicinal and economic plants. 644 A TEXT-BOOK OF BOTANY. 4 I. ORDER ERICALES. The plants of this order are distinguished by the fact that the stamens are mostly free from the perianth tube. a. PIROLACE/E.- -The plants are small, mostly evergreen perennials, and are represented in the United States by several genera. Chimaphila uinbcllata (Prince's pine or Pipsissewa) is a small trailing or creeping plant producing distinct flower- and leaf- branches. The leaves are used in medicine. The flowers are in small corymbs and the petals are white or pinkish. In Chimaphila metadata the leaves are lanceolate, mottled with white along the veins and the flowers are considerably larger. \Yith the Pirolaceas are sometimes grouped the saprophytic plants of the genus Monotropa. There are two representatives of this genus which are common in the United States, namely, Indian pipe (Monotropauniflora} and false beech-drops (M. Hypopitys). The latter contains a glucoside or an ester of methyl salicylate, and a ferment gaultherase (Fig. 349). b. ERICACEAE OR HEATH FAMILY.— This is a large family and the plants are widely distributed, especially in the northern mountainous parts of both the Eastern and Western Con- tinents. They vary from perennial herbs to trees. The flowers are usually regular, the stamens being mostly 2-spurred (Fig. 221, S), and the fruit is either a superior or inferior drupe or berry (Fig. 280, H). Arctostaphylos Uva~Ursi is a low branching shrub which trails or spreads on the ground. The leaves are used in medicine (Fig. 355). The flowers are small, white or pink, few and in short racemes. The fruit is a red, globular drupe. Trailing arbutus (Epigcca re pens] is a trailing, shrubby, hairy plant with broadly elliptical or ovate, coriaceous, evergreen leaves and white or rose-colored, fragrant flowers which are either per- fect, with styles and filaments of varying length, or dioecious. The leaves contain similar constituents to those in Uva-Ursi and Chimaphila (Fig. 353). The leaves of wintergreen (Gaultheria procumbens) are the source of true oil of wintergreen, which consists almost entirely CLASSIFICATION OF ANGIOSPERMS. 645 FIG. 349. Indian Pipe (Afonotropa uni flora), a parasitic plant of the Ericaceas growing on roots of various plants and on decomposing vegetable matter. The stems are white or yellowish-red, furnished with scales or bracts in place of leaves, and surmounted usually with a single nodding flower becoming in fruit erect. — After Troth. 646 A TEXT-BOOK OF BOTANY. FIG. 350. Purple Azalea or Pinkster Flower (Rhododendron nudiflorum), showing the upright lower stalk surmounted by several spreading branches, each bearing a number of showy tubular flowers at its extremity. The flowers of this plant often appear before the leaves. CLASSIFICATION OF ANGIOSPERMS. 647 of methyl salicylate. It contains a small quantity of an alcohol and an ester giving the characteristic odor. The same principles FlG. 351. Great Laurel or Rose Bay (Rhododendron maximum'), an evergreen shrub found in low woods and along streams, chiefly in the mountains of the eastern United States, often forming impenetrable thickets. It is one of the most beautiful of the flowering shrubs, producing from scaly, cone-like buds numerous corymbose clusters of flowers varying from pale rose to white. — After Troth. probably also occur in several other species of Gaultheria (Fig. 354). 648 A TEXT-BOOK OF BOTANY. FlG. 352. Mountain Laurel (Kalmia latifolia). This is a handsome evergreen shrub growing on rocky hills and in damp soils in the eastern United States. The foliage is bright green, and the showy flowers occur in terminal corymbs, being either of a whitish or pink color. The leaves of many species of Kalmia are said to be poisonous to animals, which is especially true of the Sheep Laurel, known as Lambkill (Kalmia angustifolia), which is not infrequent on hillsides and pastures. — After Troth. The poisonous principle andromedotoxin is found in a number of species of Rhododendron, Leucothoe, and Pieris. This principle is a powerful emetic and one of the most toxic principles known. CLASSIFICATION OF ANGIOSPERMS. 649 FIG. 353. Trailing Arbutus or Mayflower (Epig&a repens). This is one of the first of the early spring flowering plants. It is a prostrate woody plant, usually more or less covered up with the autumn leaves and with rounded and heart-shaped evergreen leaves. The flowers occur in small axillary clusters, are of a rose-red color, dimorphic as to styles and stamens, and are very fragrant. They are transplanted with difficulty, and require an acid soil, as do many other Ericaceae. — After Troth. 650 A TEXT-BOOK OF BOTANY. FIG. 354. Wintergreen, teaberry (Gaultheria procumbent), a low shrub producing slender stems lying at or beneath the surface of the earth and having ascending flowering branches rising to a height of 7 to 12 cm. The leaves are evergreen, obovate or oval, and very spar- ingly toothed; the flowers are whitish, urn-shaped and axillary. The fruit is capsular, sur- rounded by the fleshy calyx, which forms the reddish aromatic globular berries. — Bureau of Plant Industry, U. S. Department of Agriculture. CLASSIFICATION OF ANGIOSPERMS. 651 FIG. 355. Bearberry (Arctostaphylos Uva-ursi), a trailing, shrubby plant with thick evergreen, alternate leaves and whitish flowers in terminal racemes. The fruit is a globular, reddish, berry-like drupe about the size of a pea, with a mealy, insipid pulp. A. alpin a, grow- ing in the Alpine summits of Maine and New Hampshire, develops a blackish drupe with a juicy and edible pulp. — Bureau of Plant Industry, U. S. Department of Agriculture. 652 A TEXT-BOOK OF BOTANY. FIG. 356. Black or High-bush Huckleberry (Gaylussacia baccata or G. resinosa). An erect shrub with straggling branches, having leaves and flowers that are densely covered with resinous dots; the leaves vary from oval to oblong; the flowers are reddish-yellow, clustered in short racemes on terminal and axillary branches; the fruit is a sweet, blackish, berry-like drupe. In some varieties it is smooth and shiny, in others it is bluish and covered with a bloom. — After Brown. CLASSIFICATION OF ANGIOSPERMS. C53 It probably occurs in the nectar of the flowers of Kalmia and Rhododendron, being the cause of the poisonous properties of the honey from this source. The leaves of several species of laurel FIG. 357- Dwarf Blueberry or Early Sweet Blueberry (Vaccinium pennsyhanicum}. A low shrub growing to a height of 2 to 6 dm. The leaves are lanceolate or oblong, of a bright green color and minutely serrate with bristle-pointed teeth; the flowers are few, in short racemes, the corolla being whitish and cylindrical; the berries are bluish, covered with a bloom, and ripen during July and August. — After Brown. (Kalmia) contain considerable quantities of this principle, and are poisonous to cattle. The plants of the genus Gaylusaccia are small shrubs distin- guished by having an inferior, berry-like drupe with ten loculi. To this genus belong the huckleberries, as black huckleberry 654 A TEXT-BOOK OF BOTANY. (G. baccata) ; blue huckleberry (G. frondosa) ; and dwarf huckle- berry (G. dumosa). The latter plant grows in sandy swamps in both the United States and Canada and the fruit ripens in May and June. The fruits of the other two species ripen in July and August (Fig. 356). FIG. 358. Low Blueberry or Blue Huckleberry (V actinium vacillans). A small shrub with yellowish-green branchlets having nearly entire, narrow, obovate leaves. The flowers are in racemose clusters, appearing before the leaves are half grown, as shown in the illustration; the corolla is pinkish- white, oblong-cylindrical, and somewhat constricted at the throat. The berries are blue, covered with a bloom, and ripen in August and Sep- tember.— After Brown. The plants belonging to the genus Vaccinium vary from very small shrubs to tree-like shrubs and the fruit is an inferior, 5-locular berry with numerous seeds. The blueberries or bilberries (whortleberries) are the fruits of several species of Vaccinium. CLASSIFICATION OF ANGIOSPERMS. 65S The low-bush blueberry (V . pennsylvanicum) yields the berries which ripen in June and July, while the high-bush blueberry ( V . corymbosum) furnishes the fruits which are found in the market in July and August (Figs. 357, 358). FIG. 359. Small Cranberry (V actinium Oxycoccos). A trailing evergreen shrub, which produces slender erect or ascending branches with oblong revolute leaves, rose-colored nodding flowers, and a 4-locular, reddish, acid fruit. The berry of the American Cranberry (V. macrocarpon) is much larger and furnishes the fruit of the market. There are many varieties in cultivation. — After Brown. The bilberry of Europe, V actinium Myrtillus, a plant growing in Northern Europe and Asia and the Western United States and Canada, is said to destroy Bacillus typJiosus and B. Coli, an infusion of the dried berries being used for this purpose. The leaves of this plant contain ericolin and kinic acid. 656 A TEXT-BOOK OF BOTANY. Cranberry is the fruit of several species of Vaccinium which are sometimes grouped in a separate genus, Oxycoccos. There are two principal species : The large or American Cranberry ( V . macrocarpori) in which the berries are ovoid or oblong and the small or European Cranberry ( V. Oxycoccos) in which the berries are globose. The berries contain from 1.4 to 2.8' per cent, of citric acid; and a bitter glucoside, oxycoccin (Fig. 359). Many attempts have been made to cultivate the blueberry, trailing arbutus, and other plants of the Ericaceae. For some years a number of the agricultural experiment stations in the United States have attempted to grow the blueberry as a fruit, but none of these attempts has resulted in the commercial success of blueberry culture, and the experimental results have been chiefly of a negative character. The reason for this has been due, as pointed out by Coville (Bull. No. 193, Bureau of Plant Industry, U. S. Department of Agriculture), to a misunderstanding of the soil requirements for this plant. Plants will thrive only in soil having the following properties : I. The soil must have a distinctly acid reaction, such as is found in peat bogs or on the surface of the ground in sandy, oak, or pine woods. 2. Aeration of the soil is necessary. The rootlets of the swamp blueberry are remarkable in having no root hairs whatsoever, so that their absorptive surface is only about one-tenth that of other plants having root hairs. The growth of the rootlet of the blueberry is much less than that of other plants, being about at the rate of only I mm. per day under favorable conditions. The rootlets of healthy blueberry plants are inhabited further by a mycorrhizal fungus which apparently has the property of assimilating nitrogen. II. ORDER PRIMULALES. Of the three families belonging to this order, there are two which are to some extent represented in temperate regions. a. PRLMULACE/E OR PRIMROSE FAMILY.— The plants are mostly perennial herbs with perfect regular flowers, and capsu- lar fruits. The family is chiefly of horticultural interest, as it contains the genera Primula and Cyclamen. There are several species of Primula cultivated, and they are among the most popular and beautiful of the florist's flowers (Fig. 360). Several of the CLASSIFICATION OF ANGIOSPERMS. 657 FIG. 360. Primula (Primula obconica), one of several species of Primula which are cultivated in greenhouses and as house plants. The leaves are circular heart-shaped, long petiolate, and very hairy; the flowers are pinkish or lilac color and occur in umbels. The hairs of this plant are very irritating, and cause a dermatitis similar to that produced by poison ivy. — After Guernsey. species are found in Northern United States and Canada. Dur- ing recent years it has been reported that the wild primrose (P. •farinosa) and also the cultivated species (P. obconica) possess 42 658 A TEXT-BOOK OF BOTANY. hairs which are very irritating and cause a dermatitis similar to that produced by poison ivy. A number of the primulas have been examined chemically. The subterranean parts of Primula officinalis contain two crystal- line glucosides, primeverin and primulaverin, which by the action of the ferment, primeverase, produce an anise-like odor. The odors of the other species of Primula are probably due to distinct glucosides: (a) one producing an anise-like odor, as in P. offici- nalis, P. capitata, and P. denticulata; (b) one producing the odor of methyl salicylate, as in P. longiflora, P. elatior, and P. vulgaris; (c) one producing the odor of coriander, as in P. auricula, P. panonica, and P. Palinuri. The flowers of a number of species are light in color and somewhat luminous in the dark. b. PLUMBAGINACEyE OR LEADWORT FAMILY.— Perennial, mostly acaulescent herbs, growing in saline locations. Sea lavender or marsh rosemary (Limonium carolinianum) is found in the salt meadows from Labrador to Texas. The plant is reported to contain tannin and has been used in medicine. III. ORDER EBENALES. This order includes three families which are chiefly indig- enous to the Tropics. The leaves are alternate, and the flowers vary in the different families, the fruit being a berry or drupe. a. SAPOTACE^ OR SAPODILLA FAMILY.— The plants usually have a milky latex, and many of them yield GUTTA-PERCHA, of which the following may be mentioned: Palaquium Gutta, P. oblongifolium, P. borneense and P. Treubii, all growing in the East Indies. The latex is obtained by incising the trees and collect- ing the exuding juice in suitable vessels. It soon coagulates and forms grayish or reddish-yellow hard masses, which are plastic at 65° to 70° C. Owing to the fact that the material is plastic when heated and firm and tenacious when cold, it is used for a variety of purposes, as in the manufacture of surgical instruments and as a material for filling teeth. Gutta-percha as it exudes from the tree is supposed to consist of a terpene-like hydrocarbon, which on coagulation is oxidized, forming a number of resinous compounds. The plants of other genera of this family also yield CLASSIFICATION OF ANGIOSPERMS. 659 gutta-percha, as Mimusops Balata, M. Elengi, and about fifteen species of Payena growing in the East Indies. GUM BALATA is obtained from Mimusops Balata, a tree of Guiana. The gum is more resinous and flexible than gutta-percha. It contains /?-amyrin acetate and probably lupeol acetate. A gum resembling gutta-percha is obtained from the Sabodilla tree (Achras Sapota}. This gum is known in commerce as GUM CHICLE and is obtained from Yucatan. It is whitish, brittle, and yet somewhat elastic, aromatic, and contains 45 per cent, of a colorless crystallizable resin, soluble in alcohol and ether ; and iS per cent, of caoutchouc. It is used in large quantities in the making of chewing gum. The seeds of Illipe butyracea yield a fixed oil which is known as VEGETABLE BUTTER. A fixed oil is also obtained from other species of Illipe as well as various species of Bassia, Argania, and Butyrospermum, that from the latter being known as ' shea butter." The family is notable on account of the hard woods, known as IRONWOODS, which it furnishes, these being yielded by Mimusops Kauki of Farther India and tropical Australia and Argania Side- roxylon of Southwestern Morocco. A number of species also yield highly prized edible fruits, as the SAPOTILLA yielded by Achras Sapota indigenous to the Antil- les and cultivated in tropical countries, and STAR APPLE yielded by Chrysophyllum Cainito of tropical America. b. EBENACEyE OR EBONY FAMILY.— The plants differ from those of the preceding family in not containing a latex. The flowers are monoecious or dioecious and they usually have from two to eight styles. The chief interest is in the genus Diospyros, which yields the wood known as EBONY. Black ebony is obtained from various species of Diospyros growing in tropical Africa, and Asia, and the Philippine Islands. White ebony is obtained from several species of Diospyros growing in the Philippines. A red ebony is obtained from D. rubra of Mauritius, a green ebony from D. Chloroxylon of Farther India, and a striped ebony from several species growing in the Philippines. PERSIMMON fruit is obtained from Diospyros I'injiniana, a tree growing from Rhode Island south to Texas. The astrin- 66o A TEXT-BOOK OF BOTANY. gency of the unripe fruit is due to the tannin which it contains. "\Yhen it is ripe, which is not until after the appearance of frost, it is palatable and contains considerable malic acid and sugars. The Japanese persimmon is a cultivated variety of D. Kaki and produces a large orange-colored fruit which is not uncommon in the fruit markets in many parts of the world. At the present time the plant is cultivated in California. The bark of our native persimmon is used in medicine. It contains considerable tannin which resembles gallotannic acid, and a crystalline resinous principle with a peculiar odor and slightly astringent taste. c. STYRACACE/E OR STORAX FAMILY.— The flowers of this family somewhat resemble those of the Ebenacese, but the filaments of the stamens are united in a single series, and there is a single slender style. Styrax Benzoin is a medium-sized tree with long, ovate, acu- minate leaves which are very hairy on the under surface. The flowers occur in terminal racemes, and are silvery white on the outer surface and reddish-brown on the inner surface. The bal- samic resin yielded by this plant is official as benzoin. IV. ORDER GENTIANALES OR CONTORTJE. The plants of this order have opposite leaves, the flowers are regular and the gynsecium consists of two separate carpels. The order includes five families, all of which furnish medicinal plants. a. OLEACE^E OR OLIVE FAMILY.— This family is chiefly of interest because of the olive and manna trees. The olive tree (Olea europcea) is indigenous to the Orient and is now cultivated extensively in Southern Europe, Northern .Africa, the islands of the Mediterranean, tropical America, includ- ing the Southern United States, and in California. The leaves are narrow-lanceolate, entire, coriaceous and evergreen. The flowers are small, white, diandrous and in axillary racemes. The fruit is a drupe, the sarcocarp of which is rich in a fixed oil known as olive oil. The oil is obtained by expression, and is official. Depending upon the character of the fruits and the amount of oil which they yield, over forty varieties are recognized. CLASSIFICATION OF ANGIOSPERMS. 661 The fresh green olives contain a glucoside oleuropein, which disappears on the maturation of the fruit. Fraxinus Ornus is a tree resembling the ash, with 7-foliate leaves, and polygamous flowers occurring in compound racemes. The fruit is a flat samara with the wing at the apex. The sac- charine exudation from this plant is official as manna. The white ash (Fraxinus americana) is a valuable tree on account of the timber which it yields. The bark contains a bitter glucoside, f raxin, the solutions of which are fluorescent ; a bitter substance, f raxetin ; an ethereal oil of a butter-like consistency, and tannin. Some of these principles are also found in other species of Fraxinus growing in the United States and Europe. The bark of the fringe tree (Chionanthus virginica) of the Southern United States contains an intensely bitter glucosidal principle, chionanthin, and possibly also saponin. The leaves of the garden lilac (Syringa viilgaris) contain a crystalline glucoside, syringin, and syringopicrin, both of which are probably also found in other species of Syringa as well as the bark and leaves of privet (Ligustrum vulgare), which latter plant is extensively used for hedges. b. LOGANIACE^E OR LOGANIA FAMILY.— The plants are variable in character, being herbs, shrubs, trees or vines. Yellow jessamine (Gelsemium sempervirens) is a twining woody vine, sometimes trailing on the ground for a considerable distance. The leaves are oblong-lanceolate and evergreen. The flowers are bright yellow and dimorphic. The fruit is a septi- cidally dehiscent capsule. The rhizome and roots are official. Carolina pink (Spigelia marilandica) is a perennial herb with ovate-lanceolate, more or less acute and nearly sessile leaves, The flowers are yellow on the inner and scarlet on the outer surface, and occur in a i -sided spike or scorpioid cyme. The fruit is a loculicidal, few-seeded, 2-valved capsule (Fig. 361). The rhizome and roots are official. Strychnos Nux-vomica is a small tree with broadly elliptical, 3- to 5-nerved, reticulately-veined, somewhat acuminate, cori- aceous leaves. The flowers are whitish and in terminal cymes. The fruit is a berry of varying size and contains several seeds, the seeds being official. 662 A TEXT-BOOK OF BOTANY. CURARE, which is used by the Indians of South America as an arrow-poison, is supposed to be made from the bark of Strych- nos to. \~ifcra growing in Guiana, and probably other species of FIG. 361. Carolina pink (Spigelia mar Handicap showing the rhizome bearing two branches with opposite leaves and flowers in terminal scorpioid cymes. this genus. The active principle of this poison is the alkaloid curarine, which when administered hypodermically has a powerful action resembling that of digitalis. CLASSIFICATION OF ANGIOSPERMS. 663 FIG. 362. • Closed Gentian (Gentiana Anarewsii), probably one of the most abundant of the fall-flowering Gentians. It is a perennial, forming stout, leafy stems, terminated by sessile clusters of blue flowers. The corolla is closed, and hence this Gentian is sometimes called "Bottle Gentian." It grows in moist ground throughout most of the eastern United States and Canada. — After a photograph by Troth. c. GENTIANACE/E OR GENTIAN FAMILY.— The plants are mostly herbs with regular, perfect, showy flowers occurring usually in small cymes or racemes (Fig. 362). Yellow gentian (Gentiana lutca) is a large, perennial herb 664 A TEXT-BOOK OF BOTANY. (see Vol. II) with large, 5- to 7-nerved, broadly elliptical leaves. The flowers are yellow and occur in axillary cymes. The fruit is a 2-valved, ovoid capsule. The rhizome and roots are official. Many of the gentians are among the most highly prized of the wild flowers, some of them, as the fringed gentian (Gentiana crinita), being one of the most beautiful. The closed gentian (Fig. 357), so called because the flowers remain closed, is quite abundant in moist grounds throughout most of the United States and Canada. The roots of a number of species of American gentian have medicinal properties resembling that of G. lutca. Menyanthes, the yellowish-white horizontal rhizome of Men- yanthes trifoliata (Fig. 363), contains an amorphous glucoside which is slightly soluble in water, soluble in alcohol, and is precipi- tated with tannin. Upon hydrolysis menyanthin yields a volatile oil possessing an odor reminding one of bitter almonds. Swertia Chirata. — The entire plant is official. HERBA CENTAURII MINORIS, the entire plant of Erythrcca Cen- taurium of Europe, contains a glucoside, erytaurin, which forms small colorless prismatic and bitter crystals and is slowly hydro- lyzed by emulsin. Sabbatia Elliottii, occurring in the pine barrens of the Southern States, is known as the " quinine herb." d. APOCYNACE/E OR DOGBANE FAMILY.— The plants vary from perennial herbs to shrubs and trees, contain an acrid latex, and have flowers with the stigmas and styles united and the stamens distinct. They are mostly found in the Tropics. Apocynmn cannabinum is a perennial herb with erect or ascend- ing branches. The leaves are oblong-lanceolate, opposite, nearly sessile or with short petioles (Figs. 226, 251). The flowers are greenish-white, the lobes of the corolla being nearly erect and the tube about as long as the calyx. The fruit is a slender, terete follicle containing numerous seeds tipped at the micropylar end with a tuft of hairs. The root is official. The root of a closely related species, namely, spreading dog- bane (Apocymun andros&mifolium) , is sometimes substituted for the official drug. The plant is distinguished by being more spreading in its habit. The leaves are ovate (Figs. 226, 364), the flowers are pinkish, the lobes being revolute, and the tube several times as long as the calyx. CLASSIFICATION OF ANGIOSPERMS. 665 FIG. 363. Buckbean or Bogbean (Menyanthes trifoliate.) , a perennial herb with a fleshy horizontal rhizome, producing erect stems, bearing three oval or oblong leaflets, and a raceme with numerous, white or rose-colored, fringed flowers. The plant grows in bogs and shallow water in northern United States and Canada. — Bureau of Plant Industry, U. S. Department of Agriculture. 666 A TEXT-BOOK OF BOTANY. FIG. 364. Spreading Dogbane (Apocynum androsami 'folium), a perennial, branching herb, with ovate-oblong, opposite leaves, and small, pinkish fragrant flowers occurring in terminal cymes. All parts of the plants contain a white acrid latex. — After Brown. Strophanthus Kombe. — The plant is a woody climber with elliptical-acuminate, hairy leaves. The flowers are few, charac- terized by long styles, and occur in axillary racemes. The fruit consists of two long follicles containing numerous awned seeds, CLASSIFICATION OF ANGIOSPERMS. 667 which are official. In the closely related plant S. hispidus the flowers are numerous and occur in terminal cymes. FIG. 365. Butterfly-weed or Pleurisy-root (Asdepias luberosa), showing the sessile, oblong- ovate leaves and the simple, many-flowered umbels. QUEBRACHO or ASPIDOSPERMA is the bark of Aspidosperma Quebracho-bianco, a tree growing in Argentine. It contains a number of alkaloids and is used to some extent in medicine. 668 A TEXT-BOOK OF BOTANY. The leaves and bark of the cultivated oleander (Neriitm Olean- der) contain the glucoside oleandrin, resembling digitalin in its action ; a fluorescent principle, and probably several other principles. The common periwinkle ( Vinca minor) contains the principle vincin, which is supposed to be a glucoside and which probably occurs in other species of Yinca. e. ASCLEPIADACE^: OR MILKWEED FAMILY.— The plants somewhat resemble those of the Apocynaceae. The flower, however, is distinguished by having distinct styles, a 5-lobed corona connecting the corolla and stamens, which latter are mostly monadelphous, and pollen grains that are coherent, forming char- acteristic pairs of pollinia. Few of the plants are of any economic importance. The latex of the stems and the hairs of the seeds are deserving of attention. PLEURISY ROOT, which was formerly offi- cial, is obtained from Asclepias tuberosa, a plant growing in the Eastern United States and one of the two members of this genus that have orange-colored flowers (Fig. 365). CONDURANGO is the bark of Marsdenia Cundurango, a liane of Ecuador and Colombia. It occurs in quilled pieces, the bark being from 2 to 6 mm. thick. Externally it is brownish-gray and with a more or less scaly cork. The taste is bitter, acrid, and aromatic. The drug contains an amorphous glucoside ; an unsatu- rated alcohol occurring in large prisms; and a volatile oil (0.3 per cent.). V. ORDER POLEMONIALES OR TUBIFLORyE. This is a large order of plants, which are mostly herbaceous. The leaves are either opposite or alternate ; the flowers are regular or irregular, the stamens being usually adnate to the corolla. a. CONVOLVULACEJE OR MORNING-GLORY FAM- ILY.--The plants are mostly herbs or shrubs, frequently twining (to the left). They are found mostly in the Tropics, but quite a number of genera occur in temperate regions (Fig. 366). Exogoninm Pnrga is a perennial twining herb with distinctly veined, cordate leaves ; purple flowers with the stamens exserted, and occurring in cymes. The fruit is a 2-locular capsule. The CLASSIFICATION OF ANGIOSPERMS. 669 plants produce slender rhizomes with tuber-like roots, these being used in medicine. Convolvulus Scaninwnia is a perennial twining herb, with a large tap root, containing a resinous latex, and is the source of the official scammony root. The leaves are sagittate ; the flowers are large, yellowish-white and funnel- form, as in the morning- FIG. 366. Great bind weed (Convolvulus sepium) showing trailing or twining habit, the hastate leaves and funnel-shaped corolla. The plant is very resistant to noxious fumes and is usually found in smelter regions. glory, and occur in the axils of the leaves, either solitary or in clusters. The fruit is a 4-seeded, 4-locular, dehiscent capsule. A number of the plants of the Convolvulaceae are cultivated, probably the most important of which is the SWEET POTATO vine (Ipomcca Batatas), a plant extensively cultivated in tropical and sub-tropical countries on account of the edible tuberous roots. The roots contain from 3 to 10 per cent, of sugar and 9 to 15 per cent, of starch, which occurs in larger proportion in plants grown 670 A TEXT-BOOK OF BOTANY. in sub-tropical countries. The starch is a commercial product and is known as sweet-potato starch or BRAZILIAN ARROW-ROOT. The grains are more or less bell-shaped and 2- or 3-compound, about the size of wheat-starch grains, and in other ways resemble those of tapioca. To this family also belongs rather an interesting group of parasitic plants, namely, dodder (Cuscuta). They contain the principle cuscutin, and quite a number have been used in medicine. b. POLEMONIACE^: OR POLEMONIUM FAMILY.— A family mostly of herbs and chiefly of horticultural interest. It contains the genus Phlox, which is indigenous exclusively to North America. A number of the species are cultivated and are included among the most valuable hardy, herbaceous perennials. The flowers are among the most beautiful and persistent of our garden plants. Another interesting genus belonging to this family is Polemonium, a number of species of which have been long under cultivation as border plants. Polemonium rcptans is rather com- mon in the woods of the Northern United States (Fig. 367). c. HYDROPHYLLACE;E OR WATERLEAF FAMILY.— The plants are herbs or shrubs which are indigenous to Western North America. Very few of the plants of this family are of use medicinally, although quite a number are ornamental plants. Eriodictyon calif ornicum (E. glutinosum) or Yerba Santa is a shrub growing in Northern Mexico and California. The leaves are official (Fig. 368). The flowers are funnel-form, white or purple, occurring in cymes. The fruit is a dehiscent capsule and the seeds are small and few. d. BORAGINACE^E OR BORAGE FAMILY.— The plants are mostly herbs with regular blue flowers, occurring in scorpioid inflorescence. The best examples of the group are the forget-me-not (Myosotis), the roots of several species of which have been used in medicine ; and the garden heliotrope (Heliotropum peruvianum) , the fragrance of the flowers being due to a volatile oil. This plant, as well as other species of Heliotropum, contains a poisonous volatile alkaloid. At one time considerable interest attached to ALKANET, the root of Alkanna tinctoria of Southern Europe and Asia, on account of the red coloring principle aikannin, which is soluble in alcohol, CLASSIFICATION OF ANGIOSPERMS. 671 FlG. 367. Greek Valerian (Polcmonium reptans), a perennial, 2 to 4 dm. in height, having alternate pinnate leaves and light blue flowers in corymbs. — After Brown. ether, fixed and ethereal oils, but insoluble in water. COMFREY or SYMPHYTUM is the root of Symphytum officinalc and other species of this genus naturalized from Europe in waste places in the United States. It occurs on the market in small, purplish- 672 A TEXT-BOOK OF BOTANY. FIG. 368. Yerba Santa (Eriodictyon calif ornicum), a low, evergreen, aromatic shrub, the leaves and stems being covered with a resinous exudation. The leaves are lanceolate, irregularly serrate or nearly entire, and woolly hairy beneath; the flowers are violet or purple in color, and occur in cymose panicles. — Bureau of Plant Industry, U. S. Depart- ment of Agriculture. CLASSIFICATION OF ANGIOSPERMS. 673' black, more or less curved pieces, which are quite mucilaginous and astringent to the taste. The drug contains a gluco-alkaloid, consolidin, and an alkaloid, cynoglossine. It also contains a small amount of amylo-dextrin, i.e., starch which is not colored blue with iodine, and tannin. The root and herb of HOUND'S TOXGUE (Cynoglossuin officinale) are both used in medicine. The drug contains the powerful alkaloid cynoglossine, which resembles cura- rine in its action ; and the gluco-alkaloid, consolidin. e. VERBENACE/E OR VERVAIN FAMILY.— The plants are chiefly herbs or shrubs with usually opposite or verticillate leaves and more or less irregular flowers (Fig. 369). To' this family belongs the group of verbenas, some of which ar£ used in medicine, as blue vervain (Verbena Jiastata), which resembles eupatorium in its medicinal properties ; nettle-leaved vervain (V '. urticifolia) , which contains a bitter glucoside. The drug LIPPIA MEXICANA consists of the leaves of Lippia dulcis mexicana, and contains a volatile oil, the camphor lippiol, tannin, and quercetin. Lippia citriodora, found growing in the central part of South America, contains a volatile oil, of which citral is a constituent. TEAK-WOOD, which is one of the hardest and most valuable of woods, is derived from the teak tree (Tectona grandis), a large tree indigenous to Farther India and the East Indies. /. LABIATE OR MINT FAMILY.— The plants are mostly aromatic herbs or shrubs, with square stems, simple, opposite leaves, bilabiate flowers, and a fruit consisting of four nutlets. The calyx is persistent, regular or 2-lipped and mostly nerved. The corqlla is mostly 2-lipped, the upper lip being 2-lobed or entire, and the lower mostly 3-lobed. The stamens are adnate to the corolla tube, and are either 4 and didynamous, or 2 per- fect and 2 aborted. The ovary is deeply 4-lobed (Fig. 280, /). The Labiatse are especially distinguished on account of the volatile oils which they yield, and a few contain bitter or glucosidal principles. i. The following PLANTS ARE USED IN MEDICINE: Scutcllaria latcriflora (skullcap). The plant is a perennial herb producing slender stolons somewhat resembling those of 43 674 A TEXT-BOOK OF BOTANY. FIG. 369. Blue Vervain (Verbena hastata), a tall, perennial herb, with oblong-lanceolate leaves, and numerous terminal spikes of violet-blue flowers. — After Brown. CLASSIFICATION OF ANGIOSPERAIS. 675 FIG. 370. Mad-dog Skullcap (Scutellaria later i flora), a perennial herb growing in wet, shady places with an upright, quadrangular stern, bearing opposite ovate-oblong, serrate leaves, in the axils of which are formed the blue bilabiate flowers. — Bureau of Plant Industry, U. S. Department of Agriculture. peppermint and spearmint. The stems are erect or ascending, commonly branching and from 22 to 55 cm. high (Fig. 370). 6: A TEXT-BOOK OF BOTANY. Marrubium i-nlgc vhite hoarhound > is a perennial woolly herb with ascending branches : the leaves and flowering tops are used in medicine. .:h-ia officinalis or garden sage is a perennial, somewhat shrubby, pubescent herb. The leaves are ovate, crenulate. The flowers are bluish, somewhat variegated, the calyx and corolla both being deeply bilabiate. Only the two anterior stamens are fertile (bear anthers): the connective is transverse, the upper end bearing a perfect pollen-sac, and the lower a somewhat enlarged rudimentary pollen-sac (Fig. 223. F . Hedeoma pulcgioidcs (American pennyroyal) (Fig. 371). MEXTHA species. — The plants are nearly glabrous, diffusely branching herbs, which form leafy stolons that are perennial (Fig. 184). The leaves and flowering tops of both Mentha :ta (Fig. 372) and Mentha spicata are official. 2. VOLATILE OILS of the following plants are official : Rosmarinus oificinalis is a shrub growing in the Mediterranean countries. The plant has linear, coriaceous leaves, and bluish, bila- biate flowers, the middle lobe of the lower lip of the corolla being large, concave, and toothed on the margin. The flowering tops '.d from i to 1.5 per cent, of oil which is composed of 15 to 18 per cent, of borneol : about 5 per cent, of bornyl acetate : and pinene, camphene. camphor, and cineol. There are two commer- cial varieties of the oil. the Italian and French, the latter having the finer odor. Lai-andula officinalis ( garden lavender) is a shrub growing in the Northern Mediterranean countries, as well as in England. The leaves are linear, coriaceous : the flowers are small, light blue, bilabiate, with a tubular calyx, and occur in opposite cymes ( verticillasters). The oil is derived from the fresh flowering tops, the flowers riding about 0.5 per cent. Two kinds of oil are on the market, namely. French and English. The French oil contains 30 to 45 per cent, of 1-linalyl acetate; linalool : geraniol. both of which latter constituents occur free and as ester- The English oil con- tains about 5 to 10 per cent, of linalyl acetate and a slight amount cineol. Spike lavender ( Lavandula Spica) is sometimes dis- tilled with true lavender (see p. 679). CLASSIFICATION OF AXGIOSPER.MS. - .-V-^ .. ; " ,/- ? - s s -- , „ / FIG. s~:. American - royal (Hcdeoir: :. km annual plant --; in dry soil; having small, opposi: i loose clu often forming terminal leafy racemes. — Bureau of Plant led-.--.: - r - Thymns -ulgaris (garden thyme) is a small shrub having linear or linear-lanceolate leaves, and pale blue dowers with 6;8 A TEXT-BOOK OF BOTANY. strongly bilabiate, hairy calyx, and occur in axillary cymes. The plant grows in the mountains of Southern France. The herb FIG. 372. Peppermint. (Mentha piperita}: B, portion of shoot showing petiolate leaves; C, transverse section of leaf showing several forms of glandular hairs on lower surface, loose parenchyma (m) and palisade cells (p); D, lower surface of leaf showing stoma (s) and glandular hair (g). Spearmint (Mentha spicata): A, portion of shoot showing flowers and nearly sessile leaves; E, flower; F, outspread corolla showing cleft posterior lobe (p) and the four adnate, included stamens; G, H, hairs from calyx; I, sphere crystals (sphaerites) of a carbohydrate found in the corolla and style; J, pollen grains. contains from 0.3 to 0.9 per cent, of volatile oil, which is of a dark reddish-brown color, and contains from 20 to 25 per cent, of thymol ; and cymene, 1-pinene, borneol and linalool. The Spanish CLASSIFICATION OF ANGIOSPERMS. 679 oil of thyme contains from 50 to 70 per cent, of carvacrol, but no thymol. 3. OF OTHER PLANTS OF THE LABIATE which are of interest, the following may be mentioned : Lavandida Spica yields oil of spike, which has an odor of lavender and rosemary. The oil contains camphor, borneol, cineol, linalool, and camphene. Origanum Majorana (Sweet marjoram) is an annual culti- vated herb that has more or less oval, entire leaves, white flowers, and an aromatic odor and taste. It produces a volatile oil which contains terpinene and d-terpineol. Origanum vulgar e (Wild marjoram) grows in fields and waste places in the Eastern United States and Canada. The calyx is equally 5-toothed and the corolla varies from white to pink or purple. It contains a volatile oil having an odor somewhat like that of the oil of O. Majorana. Origanum hirtuni and O. Onites yield an origanum oil containing carvacrol and cymene. The oils obtained from Cretian Origanum are the source of commercial carvacrol. Pogostemon Patchouli, a plant cultivated in Southern China and the East and West Indies, furnishes the oil of PATCHOULI used in perfumery. Patchouly camphor and cadinene have been isolated from the oil, but nothing, however, appears to be known of the nature of the odorous principle. Hyssopus omcinalis (Garden hyssop) contains about 0.5 per cent, of volatile oil to which the characteristic odor of the plant is due. Satureia hortensis (summer savory) yields a volatile oil containing carvacrol, cymene and terpene. Ocimum Basilic mn (Sweet basil) is an herb growing in Europe, and yields an oil which is used in the preparation of Chartreuse and similar liquors. The oil contains methyl chavicol, linalool, cineol, camphor, pinene, and terpin hydrate. Melissa offrcinalis (Sweet balm) is a perennial herb indigenous to Europe and Asia and also cultivated. The leaves are ovate, dentate, and the flowers are bilabiate, the calyx being bell-shaped and I3~nerved. The taste is bitter, this being due to a bitter principle. The fresh leaves are quite aromatic and produce from o.i to 0.25 per cent, of a volatile oil containing a stearoptene. Several species of Monarda known as HORSEMINT or wild 68o A TEXT-BOOK OF BOTANY. FIG. 373. Cat Mint or Catnip (Nepeta Cataria), a hardy perennial herb with heart- shaped, oblong, deeply crenate, velvety, whitish green leaves, bearing in the axils dense whorls of light purplish flowers. It is a common weed and derives its common name from the fact that cats are fond of it, eating it and rubbing themselves upon it. — Bureau of Plant Industry, U. S. Department of Agriculture. bergamot are used in medicine. The oil was at one time official. The oil of Monarda punctata, a perennial herb found growing CLASSIFICATION OF ANGIOSPERMS. 68 1 from New York to Texas, contains thymol, thymoquinone, hydro- thymoquinone, carvacrol, cymene, and limonene. Nepeta Cataria (catnip) is a perennial herb naturalized in the United States from Europe (Fig. 373). It contains a bitter FIG. 374. (b) A mass of Ground Ivy (Nepeta hederacea) growing on an embankment, with (a) Spring Beauty (Claytonia virginica). principle, tannin, and an oxygenated volatile oil. Xcpcta hede- racea or GROUND IVY is a creeping perennial herb with blue bilabi- ate flowers and reniform leaves (Fig. 374). It contains a bitter principle and volatile oil. Citnila origanoidcs, or American DIT- 682 A TEXT-BOOK OF BOTANY. TANY, is a small perennial herb growing from New York to Florida, and characterized by its pungent aromatic properties. Lc-onurus Cardiaca or MOTHERWORT is a perennial herb nat- uralized in the United States and Canada from Europe. The FIG. 375. Flowering tops of Datura fastuosa flava, a variety of a plant growing in the East Indies, the Malay Archipelago, and tropical Africa, containing much the same con- stituents as Datura Stramonium. — After Newcomb. leaves are 3-lobed ; the calyx is 5-nerved and with 5 prickly teeth ; the corolla varies from white to pink or purple. The plant contains a volatile oil of rather an unpleasant odor ; a bitter prin- ciple; two resins and several organic acids, namely, malic, citric and tartaric. CLASSIFICATION OF ANGIOSPERMS. 683 /. SOLANACE;E OR POTATO FAMILY.- -The family includes herbs, shrubs, trees, and vines, which are most abundant in tropical regions. The leaves are alternate and vary from entire FIG. 376. Atropa Belladonna showing the alternate, petiolate, ovate, entire leaves, in the axils of which are the solitray fruits or flowers with large, leafy bracts. to dissected. The flowers are mostly regular, except in hyos- cyamus. The stamens are adnate to the corolla tube, the anthers connivent, and the pollen-sacs apically or longitudinally dehiscent. The fruit is a berry or capsule in which the sepals mostly persist 684 A TEXT-BOOK OF BOTANY. and sometimes become enlarged or inflated. The seeds have a large reserve layer, and the embryo is frequently curved. Datura Stramonium (Jimson weed, thorn apple) is a large, annual, branching herb, found in waste places in the United States and parts of Canada, being naturalized from Asia. The leaves and flowering tops are official. The large, spiny capsule is shown in Fig. 236, B. D. fastuosa (Fig. 375) has similar medicinal properties. Atropa Belladonna (Deadly nightshade) is a perennial herb producing a large, fleshy root, which is used in medicine (Fig. 376), as are also the leaves and flowering tops. Scopolia carniolica is a perennial herb with nearly entire or somewhat irregularly toothed leaves. The flowers are campan- ulate and dark purple. The fruit is a globular, transversely dehis- cent capsule (pyxidium). Hyoscyamus niger or henbane is a biennial herb (Fig. 377) , the leaves and flowering tops of which are official. Pichi is the dried leafy twigs of Fabiana imbricata, a shrub with small, scale-like leaves, indigenous to Chile. It contains a volatile oil; o.i per cent, of a bitter alkaloid; a glucoside resem- bling sesculin ; and a bitter resin. Solanum Dulcamara (Bitter sweet) is a perennial, climbing herbaceous plant, indigenous to Europe and Asia and naturalized in the Northern United States. The branches which have begun to develop periderm are collected, and were formerly official as DULCAMARA. They are cut into pieces 10 to 20 mm. long which are greenish-brown, hollow, with a sweetish, bitter taste and contain a glucoside, dulcamarin, and the gluco-alkaloid solanine (Fig. 3/8). Solanum carolincnse (Horse nettle) is a perennial herb having numerous yellow prickles on the branches and leaves. The leaves are oblong or ovate, irregularly lobed (Fig. 379). The flowers are white or light blue and occur in lateral cymes. The fruit is an orange-yellow, glabrous berry. The plant is common in waste places in Canada and the United States east of the Mississippi. The root and berries are used in medicine. The root is simple and quite long, 5 to 10 mm. in diameter, yellowish-brown, the bark readily separating from the wood. It has a narcotic odor CLASSIFICATION OF ANGIOSPERMS. 685 FIG. 377. Flowering- branch of Hyoscyamus niger annuum, showing sessile, acutely lobed leaves and two of the funnel-form flowers. — After Newcomb. and a sweetish, bitter, somewhat acrid taste. Both the root and berries contain the gluco-alkaloid solanine, which varies from 0.15 (in the root) to 0.8 per cent, (in the berries). 686 A TEXT-BOOK OF BOTANY. FIG. 378. Bittersweet (Solatium Dulcamara), a perennial, climbing or twining shrub, with several types of leaves, varying from ovate heart-shaped. The flowers arc blue or purplish and hang in loose cymose clusters. The fruit is an ovoid, reddish berry and very poisonous. It is sometimes eaten by children, producing fatal effects. — After Brown. CLASSIFICATION OF ANGIOSPERMS. 687 Capsicum fdstigiatum (Cayenne pepper) is a perennial, smooth, herbaceous, or somewhat shrubby plant, with ovate, acuminate, petiolate, entire leaves ; the flowers are greenish-white, and solitary FIG. 379. Horse nettle (Solatium carolinensel : A, portion of shoot showing flowers and fruits and spines on leaves and stem; B, longitudinal section of spine (s) and portion of stem showing glandular (g) and non-glandular (h) hairs, and cells containing small sphenoidal crystals (ca) ; C, thick-walled, strongly lignified cells of spine; D, portion of fibrovascular bundle showing small sphenoidal crystals (ca) of calcium oxalate in the cells accompanying the sieve; E, stellate, non-glandular hair; F, stoma of stem; G, diagram of cross section of flower showing sepnls (s), petals (p), stamens (a), ovary (c) ; H, longitudinal section of flower; I, stamen showing terminal pores; J, cross section of 2-locular berry; K, pollen grains, 30 /u. in diameter. in the axils of the leaves. The fruit is official and is known in commerce as African or Cayenne pepper. This plant and a num- ber of other species of Capsicum are indigenous to tropical 688 A TEXT-BOOK OF BOTANY. America, where they are extensively cultivated, as also in Africa and India. Nicotiana Tabacum (Virginia Tobacco plant) is a tall annual herb indigenous to tropical America and widely cultivated. The stem is simple, giving rise to large, pubescent, ovate, entire, decur- rent leaves, the veins of which are prominent and more or less hairy. The flowers are long, tubular, pink or reddish, and occur in terminal spreading cymes. The various forms of tobacco are made from the leaves, which are hung in barns, whereby they undergo a slow drying or process of curing. Other species of Nicotiana are also cultivated, as TV. persica, which yields Persian tobacco : and N. rustica, the source of Turkey tobacco. Tobacco leaves contain from 0.6 to 9 per cent, of the alkaloid nicotine ; an aromatic principle nicotianin or tobacco camphor, to which the characteristic flavor is due and which is formed during the curing of the leaves. The dried leaves yield from 14 to 15 per cent, of ash, consisting in large part of potassium nitrate. Solatium tuberosum (Potato plant) is indigenous to the Andes region of South America and is extensively cultivated on account of the edible tubers. The tubers (potatoes) contain about 75 per cent, of water, 20 per cent, of starch, and nearly 2 per cent, of proteins in the form of large protein crystalloids. The fruits and young shoots contain the gluco-alkaloid solanine and the alkaloid solanidine. The tubers contain a small amount of solanine, which is increased when they are attacked by certain fungi or exposed to light. (Consult pp. 142, 148, 194, and 198.) Besides the potato plant, several other plants belonging to the Solanacese yield vegetables, as the Tomato plant (Solanum Lyco- persicum) and the Egg plant (Solanum Melongena). Various cultivated species of Capsicum annuum furnish the common red peppers of the market. g. SCROPHULARIACE^E OR FIGWORT FAMILY.— The plants are herbs, shrubs or trees with opposite or alternate leaves and perfect, mostly complete and irregular flowers. The corolla and stamens show some resemblance to those of the Labi- atse in that the corolla is frequently more or less 2-lipped and the stamens are didynamous. The fruit is a dehiscent capsule and CLASSIFICATION OF ANGIOSPERMS. 689 the seeds have a reserve layer and a straight or slightly curved embryo. FIG. 380. Culver's-root (Leptandra virginica] showing the verticillate leaves and the long spike-like terminal racemes. Leptandra virginica (Veronica virginica}, or Culver's root, is a perennial herb with leaves in whorls of 3 to 9, those on the upper part of the stem being opposite. They are lanceolate, serrate, 44 690 A TEXT-BOOK OF BOTANY. and pinnately veined ; the flowers are white or bluish, tubular, and in dense racemes. The rhizome and roots are official (Fig. 380). FIG. 381. Foxglove (Digitalis purpurea): The terminal i-sided raceme with slightly irregular, declined, tubular flowers, and a leaf of the first year's plant with long, winged or laminate petiole. Digitalis purpurea (Foxglove) is a tall, biennial, pubescent herb, producing the first year a large number of basal leaves (Fig. 381), and the second, a long raceme of drooping, tubular, CLASSIFICATION OF ANGIOSPERMS. 691 slightly irregular, purplish flowers ; the inner surface of the corolla is spotted, the stamens are didynamous, and the upper calyx segment is narrower than the others. The leaves are official in all the pharmacopoeias. The Scrophulariacese are well represented in the United States, and a number of the plants have medicinal properties. The com- mon MULLEIN (Verbascum Thapsus) contains a volatile oil, two resins, and a bitter principle. The flowers of mullein contain the same principles and in addition a yellow coloring principle. Other species of Verbascum are used in medicine in different parts of the world. BUTTER-AND-EGGS (Linarid vulgaris) contains a crystalline principle, linariin, antirrhinic acid, a volatile oil, resin, and tannin. Several species of Scrophularia, as S. iwdosa of Europe and S\ marilandica of the Eastern United States, contain a pungent resin and a trace of an alkaloid. TURTLE-HEAD (Chclonc glabra] (Fig. 382) contains a bitter principle and gallic acid. The plant of HYSSOP (Gratiola officinalis) of Europe contains gratiolin, a bitter glucoside, and gratiosolin. The leaves of Curanga amara of the East Indies contain a glucoside, curanjiin, which resembles digi- talin in its action. h. BIGNONIACE^E OR TRUMPET-CREEPER FAM- ILY.- -The plants are shrubs, trees or woody vines, and are repre- sented in the United States by the catalpa tree (Cat alp a bigno- nioides) and the trumpet creeper (Tccouia radicans}. The bark, pods, and seeds of CATALPA have been used in medicine and con- tain a bitter principle, catalpin, a glucoside, and several crystalline principles. The TRUMPET CREEPER contains narcotic poisonous principles. The leaflets of CAROBA (Jacaranda Copaia} and other species of Jacaranda contain the alkaloid carobine, an aromatic resin, carobone, and a principle having the odor of coumarin. i. PEDALIACEyE. — The plants are herbs indigenous to the Tropics of the Old World, some of which are now cultivated in the Tropics of both hemispheres. Benne oil (oil of sesame) is obtained from the seeds of Sesamum indicum by expression. It consists chiefly of a glycerite of oleic acid, a glycerite of linoleic acid, and myristin, palmitin, and stearin. It is a bland, non-drying oil and is used like olive oil. 692 A TEXT-BOOK OF BOTANY. FlG. 382. Turtle-head (Chelone glabra), a perennial herb with lanceolate, serrate, opposite leaves and short, terminal spikes of whitish or purplish flowers. The corolla is bilabiate, the mouth slightly open, the upper lip broad and arched, suggesting the head of a turtle or snake, hence the-origin of the common name. — Bureau of Plant Industry, U. S. Department of Agriculture. CLASSIFICATION OF ANGIOSPERMS. 693 FIG. 383. Purple Gerardia (Gerardia purpurea, Fam. Scrophulariaceae) , a branching herb with linear leaves; and large, bright purplish-pink, bilabiate flowers. — After Brown. 694 A TEXT-BOOK OF BOTANY. j. ACANTHACE^: OR ACANTHUS FAMILY.- -The plants are mostly tropical perennial herbs, or shrubs with opposite PIG. 384. Common Plantain (Plantago major}. A very familiar weed found along waysides and in poorly kept lawns. The leaves are clustered, lying near the ground, broadly elliptical and with prominent parallel veins. The flowers occur in long, dense spikes which give rise to small, capsular fruits, being sometimes employed as a green bird food. — After Brown. • leaves ; in the mesophyll or epidermal cells and parenchyma of the axis occur cystoliths. Several genera are represented in the United States, one of which, Ruellia (Rucllia ciliosa), is the source CLASSIFICATION OF ANGIOSPERMS. 695 FIG. 385. Squaw-root, also known as Cancer-root (Conopholis americana) , one of the OrobanchacecB or root parasites. It is shown here growing on the roots of another plant. The flowering plants are from i to 2 dm. high, and consist of a cone-like stalk with fleshy scales surmounted by a spike of more or less yellowish flowers. — After Troth. 696 A TEXT-BOOK OF BOTANY. of the spurious spigelia which has been on the market for some years past. Ruellia ciliosa is a perennial herb which is distinguished from the other species of the genus Ruellia by the leaves, stems, and calyx being distinctly pubescent. The leaves are ovate-lanceolate, nearly sessile and entire ; the flowers are blue, sessile, solitary, or two or three in a cluster, in the axils of the leaves ; the stamens are 4, and exserted. The fruit is an oblong, terete capsule con- taining from 6 to 20 orbicular seeds. The plant is found from New Jersey and Pennsylvania to Michigan and as far south as Florida and Louisiana. Long cystoliths are found in some of the epidermal cells of both surfaces of the leaf. Quite a number of the plants of the Acanthaceae are used in the Tropics in medicine. One of these, Adhatoda Vasica of trop- ical Asia, contains the alkaloid vasicine, and is said to have the property of destroying algae which grow in the rice swamps. k. PLANTAGINACE^E OR PLANTAIN FAMILY.— The plants are annual or perennial herbs, represented by but few genera, but numerous species. The principal genus is Plantago, which includes 200 species that are widely distributed. Several species of Plantago are used in medicine. The common plantain (Plantago major) contains a glucoside, acubin ; emulsin ; and invertin, and the short rhizome, considerable starch. The seed- coat has an outer mucilaginous layer, and the mucilage of the seeds of Plantago Psyllium, P. arcnaria (both of Europe), and P. Ispaghida (of the East Indies) is used as a sizing material. The seeds of a number of the species of Plantago are used as bird food, particularly for canaries. /. OROBANCHACE^E OR BROOM-RAPE FAMILY.— This very interesting family is made up of plants which are parasitic upon the roots of other plants and are consequently rather light in color, as they develop no chlorophyll. Squaw-root or Cancer-root (Conopholis amcricana) has the flowers arranged in the form of a spike looking like an elongated cone, especially after the flowers have begun to turn brown (Fig. 385). Another little plant, also more or less white or yellow in color, is Beech- drops (Epifagus), which develops upon the roots of the beech. CLASSIFICATION OF ANGIOSPERMS. 697 VI. ORDER RUBIALES. The plants of this order are distinguished from all of the preceding Sympetalae by having flowers which are distinctly epigy- nous. The leaves are opposite or verticillate. a. RUBIACE^ OR MADDER FAMILY.— The plants are herbs, shrubs, or trees, and of the representatives found in the United States the following may be mentioned: Bluets (Hous- FIG. 386. Cinchona Ledgeriana: A, flowering branch; B, bud and open flower; C, fruiting branch. — After Schumann. tonia species), Partridge-berry (Mitchella repens), and Bedstraw (Galium species). In Mitchella and Houstonia the flowers are dimorphic. CINCHONA species.- -The plants are mostly trees, or rarely shrubs, with elliptical or lanceolate, entire, evergreen, petiolate, opposite leaves (Fig. 386). The flowers are tubular, rose-colored or yellowish-white, and occur in terminal racemes. The fruit is a capsule, which dehisces into two valves from below upward, the valves being held above by the persistent calyx. The seeds 698 A TEXT-BOOK OF BOTANY. 8 o o •3 I | o .^ u £ £ 5 &. v" ?M $ £"0 o rt > •£ a*0 £ .^ t-i c > •y } o u _ Q^3 S S o * C S -s "S ^ ^Hs-g ^ "^ o. § .^ 3 2 6 8? CLASSIFICATION OF ANGIOSPERMS. 699 are numerous and winged. There are from 30 to 40 species of Cinchona found growing in the Andes of South America at an elevation above 8'oo M. in a restricted area about 500 miles in length extending from Venezuela to Bolivia. The plants are FIG. 388. Ipecac plant [Cepkaelis (Uragoga) Ipecacuanha}: A, flowering shoot; B, flower in longitudinal section; C, fruit; D, fruit in transverse section; E.seed; F, annulate root. — After Schumann. cultivated in Java, Ceylon, New Zealand, and Australia, as well as in Jamaica (Fig. 387). There are two species which furnish the Cinchona bark of medicine: (i) Cinchona Ledgeriana (C. Calisaya Ledgeriaua), which has small, elliptical, coriaceous leaves, the under surface of which is reddish ; small, yellowish, inodorous flowers, and a 700 A TEXT-BOOK OF BOTANY. short capsule; (2) C. succirubra, which has large, thin, broadly- elliptical leaves, purplish-red calyx, rose-colored petals, and a very long- capsule. \Yhile C. Ledgeriana yields barks containing the highest amount of alkaloids, C. succirubra is most cultivated. Uragoga (Cephaclis) Ipecacuanha --The plants are perennial herbs 10 to 20 cm. high, with a creeping, woody, hypogeous stem. The roots are official in all of the pharmacopoeias (see Vol. II). The leaves are elliptical, entire, short-petiolate, and with divided stipules (Fig. 386). The flowers are white and form small ter- minal heads. The fruit is a blue berry, with characteristic spiral arrangement of the carpels. Coffca arabica is a small evergreen tree or shrub with lanceo- late, acuminate, entire, slightly coriaceous, dark green, short- petiolate leaves, which are partly united with the short inter- petiolar stipules at the base. The flowers are white, fragrant, and occur in axillary clusters. The fruit is a small, spherical or ellip- soidal drupe with two locules, each containing one seed, or COFFEE GRAIN. The coffee plant is indigenous to Abyssinia and other parts of Eastern Africa, and is cultivated (Fig. 389) in tropical countries, notably in Java, Sumatra, Ceylon, and Central and South America, particularly Brazil, over 600,000 tons being produced annually in the latter country. The yield of one tree is between i and 12 pounds. There are two methods of freeing the seeds from the parchment-like endocarp : In the one case the fruits are allowed to dry and are then broken ; in the other case, which is known as the wet method, the sarcocarp is removed by means of a machine, and the two seeds with the parchment-like endocarp are allowed to dry in such a manner as to undergo a fermentation, and after drying the endocarp is removed. Coffee seeds contain from I to 2 per cent, of CAFFEINE ; from 3 to 5 per cent, of tannin ; about 15 per cent, of glucose and dextrin ; 10 to 13 per cent, of a fatty oil consisting chiefly of olein and palmitin ; 10 to 13 per cent, of proteins ; and yield 4 to 7 per cent, of ash. The official caffeine is derived in part from coffee seeds. In the ROASTING of coffee there is a change in the physical character of the seeds, as well as a change in some of the constit- uents. The AROMA is supposed to be due to an oil known as coffeol, which is said to be a methyl ether of saligenin. CLASSIFICATION OF ANGIOSPERMS. 701 FIG. 389. Coffee tree growing in Costa Rica. An evergreen shrub, with elliptical leaves resembling somewhat those of the laurel. The flowers are white, fragrant, and are formed in clusters among the branches, being followed by the berry-like fruits, which when ripe are about the size of and resemble the cranberry. Each fruit contains two elliptical plano-convex seeds, which on being separated constitute the so-called coffee bean of com- merce.—Reproduced by permission of The Philadelphia Commercial Museum. 702 A TEXT-BOOK OF BOTANY. YOHIMBI (Yohimbihi) bark is obtained from Corynanthe Yo- h it nbe t a tree growing in the Cameroon region of Africa. The pieces of bark are 25 cm. or more in length, 5 to 8 mm. thick, externally dark brown or grayish-brown, and somewhat bitter. Numerous bast fibers are present, but no sclerotic cells. It yields 4 alkaloids (0.3 to 1.5 per cent.), the principal one being yohim- bine (corymbine or corynine), which forms white prismatic FIG. 390. Picking coffee in Brazil. The coffee shrub is cultivated in plantations, and when the berries are ripe they are collected either by shaking the tree and allowing the berries to fall upon a cloth or they are picked by hand directly from the branches, and removed from the field by oxen teams. More than half of the coffee of the world is grown in Brazil, the remainder being obtained in various parts of tropical America and East India. — Reproduced by permission of The Philadelphia Commercial Museum. needles, soluble in alcohol and almost insoluble in water, and on treatment with nitric acid becomes first deep green and then yellowish, changing to a cherry-red if followed with an alcoholic solution of potassium hydroxide (distinction from cocaine). A number of the Rubiacene contain valuable coloring prin- ciples, as the madder plant (Rubla tinctorum}, which is a peren- nial herb occurring wild in Southern Europe and formerly culti- vated in France and Germany on account of the coloring principle CLASSIFICATION OF ANGIOSPERMS. 703 FIG. 391. Buttonbush (Cephalanthus cccidentalis) , a small shrub growing in swamps and along streams throughout the United States. The leaves are opposite or whorled in threes. The flowers are white and densely aggregated in spherical peduncled heads; they secrete large quantities of nectar, and are sought to such a degree by the bees that the bush is often called "Honey balls." — After Troth. in its roots. The root is known commercially as MADDER, and con- tains when fresh a yellow coloring principle, which on the drying of the root breaks up into several glucosides, one of which on further decomposition yields ALIZARIN, the principle to which the /04 A TEXT-BOOK OF BOTANY. red color of the dried root is due. At present alizarin is made artificially from anthracene, a coal-tar derivative. Morinda citri folia, a shrub widely distributed in tropical coun- tries, contains a red coloring principle in the flowers and a yellow coloring principle in the roots, the latter being known as morindin and resembling the color principle in madder. The pulp of the fruit of Cape jasmine (Gardenia jasminoides) contains a yellow coloring principle resembling crocin, found in Crocus. The stem and root barks of Button-bush (Ccphalantlins occi- dentalis), common in swampy regions in the United States, are used in medicine (Fig. 391 ). The barks contain a bitter glucoside, cephalanthin, and a tasteless glucoside wrhich is fluorescent in solu- tion. MitcJiclla re pens contains a saponin-like body in the fruit and a tannin and bitter principle in the leaves. Quite a number of species of Galium (bedstraw) are used in medicine and for other purposes. A principle resembling glycyrrhizin is found in wild licorice (Galium circcczam] , a perennial herb growing in dry woods in the United States, and also in Galium lanccolatum, which is found from Virginia northward to Ontario. The yellow bed- straw (Galium verum) , naturalized from Europe, contains a milk- curdling ferment. b. CAPRIFOLIACE;E OR HONEYSUCKLE FAMILY.— The plants are perennial herbs, shrubs, trees, or woody climbers with opposite, simple or pinnately compound leaves. The flowers are perfect, epigynous, regular, or bilabiate, and arranged in corymbs. The fruit is a berry, drupe, or capsule. They are mostly indigenous to the northern hemisphere. Viburnum pninifoliiim (Black haw) is a shrub or small tree 25 cm. in diameter. The winter buds are acute and reddish- pubescent ; the leaves are ovate, elliptical, obtuse or acute at the apex, somewhat rounded at the base, finely serrulate, glabrous, and short-petiolate (Fig. 392) ; the flowers are white and in nearly sessile cymes ; the fruit is a small, oval, bluish-black, glaucous, inferior drupe. The root-bark is official. Viburnum Opnlns (Wild guelder-rose or cranberry-tree) is a shrub about half the height of V. pritnifolinm, with broadly ovate, deeply 3-lobecl and coarsely dentate pubescent leaves. The CLASSIFICATION OF ANGIOSPERMS. 705 flowers are white and in compound cymes, the outer being sterile and large and showy. The fruit is a reddish, globular, very acid drupe, clinging to the branches all winter. The Snow-ball or guelder-rose of the gardens is a sterile variety of this species. Another variety (edule*) is also cultivated on account of its edible fruits, particularly in Canada and the Northern United States. FIG. 392. Fruiting branch of Viburnum prunifolium. A number of species of Viburnum are rather common in various parts of the United States, as the Maple-leaved arrow- wood (V . accrifolium) , which is a small shrub with deeply 3-lobed, coarsely dentate leaves and small, nearly black drupes ; Arrow-wood (V. dcntatiim}, with broadly ovate, coarsely den- tate leaves and blue drupes, which become nearly black when 45 ;o6 A TEXT-BOOK OF BOTANY. ripe; Soft-leaved arrow-wood (V . molle), which somewhat re- sembles V . dentatum, but has larger leaves that are crenate or dentate and stellate-pubescent on the lower surface ; Larger withe- rod (V . mtdum), having nearly entire leaves and a pink drupe, which becomes dark blue. Sambucus canadcnsis (American elder) is a shrub growing in moist places in the United States as far west as Arizona and in Canada. The leaves are 5- to 7-foliate, the leaflets being ovate, elliptical, acuminate, sharply serrate, and with a short stalk ; the flowers are small, white, and in convex cymes. The fruit is a deep purple or black berry-like drupe. The dried flowers are used in medicine. They are about 5 mm. broad, with a 5~toothed, turbinate calyx, and a 5-lobed, rotate corolla, to which the 5 sta- mens are adnate. The odor is peculiar and the taste is muci- laginous and somewhat aromatic and bitter. The active principles have not been determined, but are prob- ably similar to those of 5. nigra. The inner bark is also used in medicine and contains a volatile oil, a crystallizable resin, and valerianic acid. It does not appear to contain either tannin or starch. The roots of elder contain a volatile principle somewhat resembling coniine. The pith consists chiefly of cellulose, is deli- cate in texture and has a variety of uses (Fig. 132). The Black elder (Sauibucns nigra), which is a shrub com- mon in Europe, is characterized by narrower leaflets, a 3-locular ovary, and black berries. The flowers are official in some of the European pharmacopoeias. They contain about 0.4 per cent, of a greenish-yellow, semi-solid volatile oil, which when diluted has the odor of the flowers. They also contain an acrid resin. The Red-berried elder or mountain elder (S. pubois] some- what resembles the common elder, but the stems are woody, and the younger branches have a reddish pith. The flowers are in paniculate cymes, and the fruits are scarlet or red. Other plants of the Caprifoliacere are also used in medicine. Horse gentian (Triosteum perfoliatum), a perennial herb with connate-perfoliate leaves and small, orange-red, globular drupes, growing in Canada and the United States as far west as Kansas, furnishes the drug (rhizome) known as WILD IPECAC or Trios- teum. The rhizome is yellowish-brown, somewhat branched, CLASSIFICATION OF ANGIOSPERMS. 707 cylindrical, 10 to 20 cm. long, 10 to 15 mm. in diameter, with numerous cup-shaped stem-scars, and coarse, spreading roots ; it is rather hard and tough, and has a bitter, nauseous taste. Triosteum contains an emetic alkaloid, triosteine, and considerable starch. The seeds of Triosteum perfoliatum are sometimes roasted and employed like coffee, the plant being known as Wild coffee. The roots and stems of the following plants are sometimes employed: The Snowberry (Syniphoricarpos racemosus), the Bush honeysuckle (Diervilla Lonicera), and various species of Lonicera, these being also known as honeysuckles. VII. ORDER VALERIANALES OR AGGREGATE. The plants are mostly herbs with an inferior ovary, which is either unilocular with a single pendulous ovule, or tri-locular with frequently but a single anatropous ovule. a. VALERIANACE^E OR VALERIAN FAMILY.— The plants are herbs with opposite, exstipulate leaves, small, perfect, or polygamo-dioecious flowers, occurring in corymbs. The fruit is dry, indehiscent, and achene-like. The calyx is persistent, be- coming elongated and plumose, and resembling the pappus in the Composite. Valeriana officinalis (Garden or Wild valerian) is a tall, peren- nial herb, more or less pubescent at the nodes. The leaves are mostly basal, pinnately parted into seven or more segments, which are lanceolate, entire, or dentate. The flowers are white or pink and arranged in corymbed cymes. The calyx is much reduced, consisting of 5 to 15 pinnately branched teeth (pappus) ; the corolla is tubular, somewhat sac-like on one side, but not spurred as in other members of this family ; the stamens are 3 in number and adnate to the corolla tube ; the stigma is 3~lobed. The fruit is ovoid, glabrous, and with a conspicuous plumose pappus. The rhizome and roots are official. The young leaves of several species of Valerianella are used as a salad and are cultivated like spinach, as the European corn- salad (V . olitoria), which is also cultivated to some extent in the United States. b. DIPSACACE;E OR TEASEL FAMILY.— The plants are annual or perennial, herbs, chiefly indigenous to the Old World. ;o8 A TEXT-BOOK OF BOTAXY. The flowers are arranged in heads on a common torus, resem- bling in some cases those of the Composite. Some of the plants are used in medicine, as the roots, leaves, flowers, and seeds of Fuller's teasel (Dipsacus fullonum), the roots of Succisa pratensis of Europe, and several species of Scabi- osa and Cephalaria. The seeds of Cephalaria syriaco, when admixed with cereals give a bread that is dark in color and bitter. This family is, however, chiefly of interest on account of Fuller's teasel, which is a cultivated form of Dipsacus jerox, indigenous to Southwestern Asia, the plant being cultivated in Europe and New York State. The elongated, globular heads, with their firm, spiny, and hooked bracts, are used in the fulling of cloth. VIII. ORDER CAMPANULAT^:. This order differs from the two preceding by having the anthers united into a tube (syngenesious). It includes three prin- cipal families, which are distinguished by differences in the char- acter of the andrcecium: (a) Cucurbitacese, in which there are three stamens, having not only the anthers united but the fila- ments also (monadelphous) ; (b) Campanulacese, in which there are five stamens, both the filaments and anthers being united into a tube; (c) Composite, in which there are five stamens, but the anthers only are united, the filaments being separate (Fig. 82, A). a, CUCURBITACE^: OR GOURD FAMILY.— The plants are mostly annual, tendril-climbing or trailing herbs (Fig. 66), mainly indigenous to tropical regions. The leaves are alternate, being opposite the tendrils, petiolate, and entire, palmately lobed or dissected. The flowers are epigynous ; the petals are borne on the calyx tube and frequently are united (campanulate) ; the ovary is i- to 3-locular and with few or many anatropous ovules. The fruit is a pepo, which is indehiscent but may burst somewhat irregularly. Citrullus Colocynthis is a trailing herb with deeply lobed leaves. The flowers are yellow, axillary, and monoecious, the staminate being with short filaments and glandular pistillodes (aborted pistils), and the pistillate having a 3-locular, globose ovary and three short staminodes. The fruijt is globular, 5 to 10 CLASSIFICATION OF ANGIOSPERMS. 709 cm. in diameter, smooth, greenish, and mottled. The fruit de- prived of the epicarp is official. Cucurbita Pcpo (pumpkin-vine) is an extensively trailing hispid vine, with large, nearly entire, cordate leaves having long petioles. The tendrils are branching. The flowers are large, deep yellow, and monoecious ; the staminate ones being in groups and the pistillate single. The fruit is a large, yellowish berry, sometimes weighing from 10 to 72 K. The seeds are numerous and are official as Pepo. Ecballium Elaterium (Squirting cucumber) is a bristly-hairy, trailing perennial herb with thick, rough-hairy, cordate, some- what undulate leaves. The flowers are yellow, monoecious. The fruit is ellipsoidal, about 4 cm. long, rough-hairy or prickly, pend- ulous, and at maturity separates from the stalk, when the seeds are discharged upward through a basal pore. The plant is indig- enous to the European countries bordering the Mediterranean, the Caucasus region, Northern Africa and the Azores. The juice of the fruit yields the drug ELATERIUM, which is official in the British Pharmacopoeia. Elaterium yields 30 per cent, of the ELATERIN of the Pharmacopoeias. From the latter by fractional crystallization from 60 to 80 per cent of a-elaterin, a laevo-rota- tory crystalline substance is separated, which is completely devoid of purgative action ; and varying amounts of /?-elaterin, a dextro- rotatory crystalline compound which possesses a very high degree of physiological activity (Power and Moore, Ph. Jour., 29, Oct. 23, 1909, p. 501 ; and Proc. Chcni. Soc., No. 362, 1909, p. 1985). Bryonia or BRYONY is the dried root of Bryonia alba (White bryony), a climbing herb indigenous to Southern Sweden, East- ern and Central Europe, including Southern Russia, and Northern Persia (Fig. 181). The root contains two bitter glucosides, bryonin and bryonidin ; two resinous principles and considerable starch. Bryonia dioica (Red bryony) also has medicinal proper- ties and is a source of the drug. B. dioica has red berries, while the fruit of B. alba is black. The latter plant is sometimes known as Black bryony, but this plant should not be confounded with Tamus coinmnnis (Fam. Dioscoreacese), of Southern Europe, the rhizome of which is known commercially as Black bryony. The fruits and seeds of various members of the Cucurbitaceae 710 A TEXT-BOOK OF BOTANY. contain powerful drastic and anthelmintic principles. A number of the plants, however, are cultivated on account of the fruits, which are used as food, as the pumpkin already mentioned, the WATER MELON ( Citrullus vulgaris) , indigenous to Southern Africa and cultivated in Egypt and the Orient since very early times ; CANTALOUPE or musk-melon, derived from cultivated varieties of Cucumis Melo, indigenous to tropical Africa and Asia, also culti- vated since early times. The common CUCUMBER is obtained from Cucumis sativus, which is probably indigenous to the East Indies. These fruits contain from 90 to 95 per cent, of water, and the water melon contains 3.75 per cent, of dextrose, 5.34 per cent, of saccharose, and yields 0.9 per cent, of ash. Luff a cylindrica is an annual plant indigenous to the Tropics of the Old World. It is cultivated to some extent in America, but especially in the Mediterranean region. The fruit is more or less cylindrical and 20 cm. or more long. The pulp is edible and the fibrovascular tissue forms a tough network, which, when the seeds, epicarp, and pulpy matter are removed, constitutes the LUFFA-SPONGE. The fruits of Luff a operculata and L. echinata, both found in Brazil, contain a bitter principle resembling colocynthin. b. CAMPANULACE^E OR BELL-FLOWER FAMILY.— The plants are mostly annual or perennial herbs, but are some- times shrubby, with an acrid juice containing powerful alkaloids. The rhizomes and roots of about twelve of the genera contain inulin. The leaves are alternate ; the corolla is regular, cam- panulate and rotate, or irregular, as in Lobelia. The fruit is a capsule or berry containing numerous small seeds. Lobelia inflate, (Indian or Wild tobacco) is an annual, pubes- cent, branching herb (Fig. 224), the dried leaves and tops of which are official (see Vol. II). About 15 different species of Lobelia are used in medicine. The most important of those grow- ing in the United States is the Cardinal flower or Red lobelia (Lobelia cardinalis), a plant found in moist soil from Canada to Texas, and characterized by its long, compound racemes of bright scarlet or red flowers. The Blue cardinal flower or Blue lobelia (L. syphilitica) is a plant of nearly the same habit and same gen- CLASSIFICATION OF ANGIOSPERMS. 711 eral character, except that the flowers are of a bright dark blue color or occasionally white. c. FAMILY COMPOSITE.— This is a large group of plants, which are annual, biennial, or perennial herbs, under-shrubs, shrubs, trees and twiners or even climbers, a few being aquatic. They contain inulin, a constituent peculiar to this group of plants. The most distinguishing character is the inflorescence, which is a head or capitulum (Fig. 228), consisting of one or two kinds of flowers, arranged on a common torus, and subtended by a number of bracts, forming an involucre. The flowers are epigy- nous and the fruit is an achene, usually surmounted by the per- sistent calyx, which consists of hairs, bristles, teeth or scales, which are known collectively as the PAPPUS (Fig. 227). The individual flowers are called florets (Figs. 241, 242), and may be hermaphrodite or pistillate, monoecious, dioecious, or neutral. Depending upon the shape of the corolla, two kinds of flowers are recognized, one in which the corolla forms a tube, which is 5-lobed or 5-cleft, known as TUBULAR FLOWERS (Figs. 227, 228, C) ; and one in which the petals are united into a short tube, with an upper part that forms a large, strap-shaped, usually 5-toothed limb, known as LIGULATE FLOWERS (Figs. 227, 228', D). In some of the plants of the Composite the head consists of ligulate flowers only, but in the larger number of plants the head is composed of both tubular and ligulate flowers or tubular flowers alone and accordingly two main groups or sub-families are dis- tinguished. The sub- family in which all of the flowers are lig- ulate is known as LIGULIFLOR.E, or CICHORIACE.E, by those who give the group the rank of a family. This group includes plants like dandelion, chicory, lettuce, and Hieracium. The group or sub-family in which the flowers are all tubular or ligulate on the margin only is known as the TUBULIFLOR.E. When the head consists only of tubular flowers it is called DISCOID, but when ligulate flowers are also present it is called RADIATE. When the heads are radiate, as in the common daisy, the tubular flowers are spoken of as DISK-FLOWERS, and the ligulate flowers as RAY- FLOWERS. The disk-flowers are usually perfect, while the ray- flowers are pistillate or neutral (without either stamens or pistils). By some systematists the Tubuliflone are divided into groups ;i2 A TEXT-BOOK OF BOTANY. which have been given the rank of families. This division is based especially on the characters of the stamens. In a small group represented by the ragweed and known as the AMBROSI- ACEJE, the anthers, while close together (connivent) , are not united, and the corolla in the marginal or pistillate flowers is reduced to a short tube or ring. In a large group, which includes probably 10,000 species and which is considered to be the COMPOSITE proper, the stamens in the tubular flowers are syngenesious and the marginal or ray-flowers are distinctly ligulate. This group includes the daisy, sunflower, golden-rod, aster, thistle, and most of the plants which yield official drugs. It may also be added that the Composite is considered to be the highest and youngest group of plants. Taraxacum officinale (Dandelion) is a perennial, acaulescent herb with milky latex ; oblong-spatulate, pinnatifid or runcinate, decurrent leaves, and with a i -headed scape, the stalk of which is hollow. The flowers are ligulate, golden-yellow and numerous ; the involucre consists of two series of bracts, the inner one of which closes over the head while the fruit is maturing, afterward becoming reflexed. The fruit consists of a loose, globular head of achenes, each one of which is oblong-ovate and with a slender beak at the apex which is prolonged into a stalk bearing a radiate tuft of silky hairs, which constitute the pappus. The root is fusi- form and usually bears at the crown a number of branches 2 to 5 cm. long, having a small pith and other characters of a rhizome. The root is official. Lactuca virosa (Poison lettuce) is a biennial prickly herb, with milky latex and oblong-obovate, spinose-toothed, runcinate basal leaves and with alternate, somewhat sessile or auriculate, scattered stem leaves, the apex and margin being spinose. The flowers are pale yellow and occur in heads forming terminal pani- cles. The involucre is cylindrical and consists of several series of bracts. The flowers are all ligulate and the anthers are sagit- tate at the base. The achenes are flattish-oblong, and the pappus, which is raised on a stalk, is soft-capillary, as in Taraxacum. The prepared milk-juice is official as Lactucarium. Eupatorium pcrfoliatum (Bonesct or Common thorough wort). — The leaves and flowers are used in medicine. CLASSIFICATION OF ANGIOSPERMS. 713 Eupatoriuui scbandiauuni, which is added to Mate as a sweet- ening agent, contains two sweet gluc.osides ; eupatorin and reban- din ; a bitter principle, and a resin. GRINDELIA species.- -The plants are perennial, greenish-yellow, resinous herbs, sometimes being under-shrubs, with alternate, sessile or clasping, oblong to lanceolate, spinulose-dentate leaves, and large, terminal, yellowish heads, consisting of both ligulate and tubular flowers. The leaves and flowering tops of Grindelia caniporum, G. cuneifolia and G. squarrosa are official. Erigeron canadensis or Leptilon canadcnsc (Canada fleabane) is an annual or biennial, hispid-pubescent herb found growing in fields and waste places in nearly all parts of the world. The stems are simple, with numerous crowded leaves and numerous flowers occurring in terminal panicles. The plants are sometimes branched and I to 3 M. high. The leaves are linear, nearly entire, of a pale green color, the lower and basal ones being spatulate, petiolate and dentate or incised. The flowers are white and the heads are composed of both ligulate and tubular florets, the former being pistillate and not longer than the diameter of the disk. The pappus consists of numerous capillary bristles and the involucre, which is campanulate, consists of five or six series of narrow, erect bracts. The fresh flowering herb contains 0.3 to 0.4 per cent, of a volatile oil which is official, tannin, and a small amount of gallic acid. The oil is obtained by distillation and consists chiefly of d-limonene. The genus Erigeron includes a number of species which have medicinal properties. E. annnus (Sweet scabious or Daisy flea- bane) is a low, branching, annual herb, characterized by its linear- lanceolate or ovate-lanceolate leaves and its conspicuous flowers, which resemble those oi the common daisy, the ray-flowers often being tinged with purple (Fig. 393). It contains a volatile oil resembling that of Canada fleabane, and tannin. The Philadel- phia fleabane (Erigeron pJiiladelphicits} is a perennial herb pro- ducing stolons, and has clasping or cordate leaves, the basal being spatulate, and is further distinguished by its light purplish-red ray-flowers. AntJicniis nobilis (Roman chamomile) is an annual or peren- A TEXT-BOOK OF BOTANY. nial, procumbent, branched herb, with numerous 2- to 3-pinnately divided leaves, the ultimate segments being narrow-linear. The flowers occur in terminal heads with long peduncles, a conical torus and few white pistillate ray-flowers. The flowers of culti- FIG. 393. Daisy fleabane (Erigeron annuus). vated plants are official (see Vol. II). the heads consisting mostly of ligulate flowers, forming so-called " double flowers," as in the cultivated chrysanthemums. Anacyclus Pyrcthrum (Pellitory) is a perennial herb resem- bling Anthcmis nobilis in its general characters. The ray-flowers, CLASSIFICATION OF ANGIOSPERMS. 715 however, are white or purplish, and the pappus consists of a ring or scale. The root is official. Matricaria Chamomilla (German chamomile) is an annual, diffusely branched herb, with pinnately divided leaves, consisting of few, linear segments. The flowers are official (Figs. 228, 394). FIG. 394. A single plant of Matricaria Chamomilla, showing finely divided leaves and numerous composite flowers. — After Newcomb. Arnica montana is a perennial herb with small rhizome; nearly simple stem ; opposite, somewhat connate, entire, spatulate, hairy leaves, and yellow flowers in large heads with long peduncles. The flowers are official. Arctlum Lap pa (Burdcck) is a coarse, branched, biennial or 716 A TEXT-BOOK OF BOTANY. FIG. 395. Chicory or Succory (Cichorium Jnty'ius}, a branching perennial herb with oblong or lanceolate, more or less clasping leaves and axillary clusters of violet-blue flowers. The plant is cultivated as a pot herb and salad, and the young roots are used like carrots. The plant is more widely grown for its roots, which are used in the preparation of a substi- tute of coffee.' — After Brown. CLASSIFICATION OF ANGIOSPERMS. 717 perennial herb, with alternate, broadly ovate, repand, entire, tcmen- tose, mostly cordate leaves, the basal ones being from 30 to 45 cm. long. The flowers are purplish-red or white, tubular and form rather large corymbose heads ; the involucre consists of numerous lanceolate, rigid, nearly glabrous bracts, which are tipped with FIG. 396. Burdock (Arctium Lappa), a biennial herb with large, mostly cordate leaves crowded at the base of the stems, and bearing small clusters of purplish flowers in the shorter branches above. It is a common roadside weed, and well known because of the burr-like fruits, consisting of the hooked tips of the bracts of the involucre. — After Brown. hooked, spreading bristles. The achenes are oblong and some- what 3~angled, and the pappus consists of numerous short bristles (Fig. 396). The root is used in medicine. The common burdock (Arctium minus} resembles A. Lappa, but is a smaller plant and is more common in the United States. The heads are smaller and the inner bracts are shorter than the 7i8 A TEXT-BOOK OF BOTANY. tubular flowers, the bristles of this series being erect and with the outer spreading. Calendula officinalis (Marigold) is an annual herb with alter- nate, spatulate, oblanceolate, entire or serrate leaves. The flowers are yellow and form solitary heads, consisting of both ray and tubular florets. In the cultivated varieties most of the tubular florets are changed to ligulate, the latter being official (Fig. 227). While the Composite include a large number of genera and species, the plants do not yield many important drugs, although a number are used in medicine and for other purposes. The so-called INSECT FLOWERS (Pyrethri F lores) are the partly expanded flower-heads of several species of Chrysanthe- mum, and are used in the preparation of a powder which is a powerful insecticide. The plants are perennial herbs resembling in their habits the common white daisy (C. Leucanthcmum) . The DALMATIAN Insect Flowers are obtained from C. cineraria: folium, growing in Dalmatia, and cultivated in Northern Africa, Cali- fornia and New York. The heads as they occur in the market are about 12 mm. broad, light yellowish-brown and have a slightly rounded or conical torus, which is about 12 mm. in diameter and consists of 2 or 3 series of lanceolate involucral scales. The ray- florets are pistillate, the corolla varying in length from i to 2 cm. and having numerous delicate veins and 3 short, obtuse or rounded teeth. The tubular flowers are perfect and about 6 mm. long. The ovary is 5-ribbed and the pappus forms a short, toothed crown. The odor is distinct and the taste bitter. PERSIAN Insect Flowers are derived from C. roseum and C. Marschallii, growing in the Caucasus region, Armenia and North- ern Persia. The heads are about the size of those of C. cineraria- folium; the torus is dark brown; the involucral scales and ray- florets are purplish-red ; the ovary is lo-ribbed. Insect flowers contain from a trace to 0.5 per cent, of a vola- tile oil, the Persian flowers containing the larger proportion, and the amount decreasing with the maturing of the flowers. They also contain two resins, varying from 4 to 7 per cent., the larger amount being found in the Dalmatian flowers ; a small quantity of a glucoside and a volatile acid. The principle toxic to insects is PYRETHRON, an amber-yellow, CLASSIFICATION OF ANGIOSPERMS. 719 syrupy substance which is the ester of certain unidentified acids, and on saponification yields the alcohol pyrethrol which crystal- lizes in fine needles. The acids combined in the ester pyrethron do* not give crystalline salts. WORMWOOD or Absinthium consists of the dried leaves and flowering tops of Artemisia Absinthium, a perennial, somewhat woody, branching herb, indigenous to Europe and Northern Africa, cultivated in New York, Michigan, Nebraska and Wis- consin and naturalized in the United States from plants that have escaped from cultivation. The leaves are grayish-green, gland- ular-hairy, I- to 3-pinnately divided, the segments being obovate, entire, or lobed ; the flowers are yellowish-green, the heads being about 4 mm. broad and occurring in raceme-like panicles ; the torus is hemispherical and the involucre consists of several series of linear bracts, the inner being scale-like ; the florets are all tubular, the outer ones sometimes being neutral. The herb is aromatic and very bitter. The fresh drug contains about 0.5 per cent, of a VOLATILE OIL which is of a dark green or blue color, has a bitter, persistent taste but not the pleasant odor of the plant, and consists of d-thujone (absinthol), thujyl alcohol free and combined with acetic, iso- valerianic and palmitic acids, phellandrene and cadinene. The other constituents of the drug include a bitter glucosidal principle, ABSINTHIIN, which forms white prisms and yields on hydrolysis a volatile oil ; a resin ; starch ; tannin ; succinic acid, potassium succinate, and about 7 per cent, of ash. The plant is used in the preparation of the French liquor known as ABSINTHE. Artemisia Cina yields the official Santonin. Other species of Absinthium also yield volatile oils, as the COMMON MUGWORT (Artemisia vulgaris], which yields from o.i to 0.2 per cent, of an oil containing cineol ; Artemisia Barrelieri, which contains an oil consisting almost entirely of thujone, and said to be used in the preparation of Algerian absinthe. SAFFLOWER consists of the dried florets of Carthamiis tinc- torius, an annual herb which is known only in cultivation. The florets are tubular, yellowish-red, the corolla tube being about 2 cm. long and with 5 small, linear lobes ; the stamens are exserted. The ovary with the long, slender style is usually not present in 720 A TEXT-BOOK OF BOTANY. the drug (Fig. 227, C). Safflower contains a small percentage of a yellow coloring principle (safflower-yellow), which is soluble in water, and 0.3 to 0.6 per cent, of a red coloring principle (car- thamin or carthamic acid), which is insoluble in water but soluble in alcohol, the solution having a purplish-red color. A volatile oil is also present. Carthamin is used in conjunction with French chalk in the preparation of a rouge. TANSY is the dried leaves and tops of Chrysanthemum (Tana- cctum vulgar e), a perennial, aromatic herb indigenous to Europe, extensively cultivated and naturalized in the United States. The leaves are large and pinnately divided, and the flowers, both tubu- lar and ligulate, are yellow, the heads being in terminal corymbs. The plant yields from o.i to 0.3 per cent, of a volatile oil, consisting of thujone, borneol and camphor; and 3 resins. ELECAMPANE (Inula Helenium) is a large, perennial, densely pubescent herb with alternate leaves and large, solitary terminal heads, consisting of yellow tubular and ligulate florets (Fig. 227). The plant is indigenous to Central Europe and Asia, and natural- ized in North America from Canada to North Carolina. The root is used in medicine and was formerly official as INULA. The root of Polymnia Uvedalia, a plant closely related to Inula, but indigenous to the United States east of the Mississippi, contains a volatile oil, a glucoside, tannin, and a resinous sub- stance consisting of two resins, one of which is pale yellow and soft, the other dark brown and hard. The following Composite, while not of very great importance, are used in some localities : YARROW (Achillea Millefolium) is a common weed naturalized from Europe (Fig. 397), and contains about o.i per cent, of a dark blue volatile oil with a strongly aromatic odor and a small amount of a bitter alkaloid, achilleine. The roots of yarrow, on the other hand, yield a volatile oil with a valerian-like odor. Achillea nobilis of Europe contains an oil resembling that of yarrow, but it is of finer quality and has a spice-like taste. Achillea nwschata, an alpine plant of Europe, yields three alkaloids and a volatile oil containing cineol, and is used in Italy in the preparation of the liquor, "Esprit d' Iva." Achillea tanacctifolia yields a blue volatile oil having the odor of tansy. CLASSIFICATION OF ANGIOSPERMS. 721 FIG. 397. Yarrow or Milfoil (Achillea Mille folium), a perennial herb, branching only at the top and bearing deeply pinnatifid leaves, the segments being very narrow. The flowers are small, white, occasionally crimson and arranged in large, terminal corymbs. — Bureau of Plant Industry, U. S. Department of Agriculture. The HIGH GOLDEN-ROD (Solidago canadciisis) yields 0.63 per cent, of a volatile oil, consisting chiefly of pinene, with some phel- 46 722 A TEXT-BOOK OF BOTANY. landrene and dipentene, and containing about 9 per cent, of borneol, 3 per cent, of bornyl acetate and some cadinene. The True or ANISE-SCENTED GOLDEN-ROD (Solidago odora) yields an aromatic volatile oil and a small amount of tannin. FIG. 398. Method of gathering the pollen of Golden-rod (Solidago Shortii) for immuniz- ing the hay-fever horses. The plant is gathered just about the time that the pollen-sacs are ready to open, then taken to a sunny room — free from draft and air disturbances- placed slanting in a basin filled with water, the blossoms drooping over the sides of the vessel, with clean, smooth paper spread underneath them. The following morning the pollen will be on the paper and can readily be gathered with a feather-top or a quill. — After Schimmel & Co. The rhizome of the large Button-snakeroot (Lacinaria scari- osa) , growing in the eastern and central portion of the United States and Canada, contains o.i per cent, of volatile oil, about 5 per cent, of resin, and 2 per cent, of a caoutchouc-like substance. CLASSIFICATION OF ANGIOSPERMS. 723 COLTSFOOT (Tussilago Farfara) is a plant indigenous to Europe and naturalized in the Northern United States and Can- ada. It is an acaulescent herb with a slender rhizome 30 to 40 cm. long ; nearly orbicular, somewhat lobed and tomentose leaves, and large, solitary, yellow flowers appearing before the leaves. The plant contains an acrid volatile oil, a bitter glucoside, resin and tannin. ECHINACEA is the root of Brauneria (Rudbeckia) purpurea, a plant growing in rich soil from Virginia to Illinois and south- ward, and of B. angustifolia, growing from the Northwest Terri- tory to Texas (Fig. 399). The drug contains an alkaloid and 0.5 to i per cent, of an acrid resinous substance to which the medical properties are due. ROSIN WEED or COMPASS PLANT (Silphium laciniatum), found growing from Ohio to South Dakota and south to Texas, produces an oleo-resin which exudes either spontaneously or from the punctures of insects, and contains about 19 per cent, of vola- tile oil, and 37 per cent, of acid resin. The THISTLE (Cnicus benedictus) contains a crystalline bitter principle, cnicin, which is colored red with sulphuric acid. The Mexican drug PIPITZAHOAC is the rhizome of Perezia Wrightii, P. nana and P. adnata, plants found in Southwestern Texas and Mexico'. It contains about 3.6 per cent, of a golden- yellow crystalline principle, pipitzahoic acid, which appears to be related to oxythymoquinone and is colored an intense purple with alkalies and alkaline earths. LION'S FOOT, the root of Prenanthes Serpentaria, P. alba and other species of Nabalus growing in the United States, contains bitter principles, resin and tannin. Mio Mio (Baccharis cordi- folia), of South America, is poisonous to sheep and cattle and contains an alkaloid, baccharine, and a bitter principle. SPINY CLOTBUR (Xanthium spinosum) contains a bitter resin and possi- bly a volatile alkaloid. The fruit of Xanthlum spinosum, a common weed naturalized from Europe, contains an amorphous, non-glucosidal substance, xanthO'Strumarin, which forms precip- itates with a number of the alkaloidal reagents. SNEEZE- WEED (Helenium autumnale) contains a volatile oil, a bitter glucoside and tannin. Helenium tenuifolhnn, of the Southern United States, 724 A TEXT-BOOK OF BOTANY. FIG. 399. A flowering specimen of the Purple Cone-flower (Brauneria angustifolia), showing the 3-nerved lanceolate leaves and 2 of the flower heads with the characteristic long spreading rays. — After Newcomb. is a narcotic poison. PARA CRESS (Spilanthcs oleracea), of trop- ical America, contains a soft pungent resin and a crystallizable principle, spilanthin. The common white daisy (Chrysanthemum CLASSIFICATION OF ANGIOSPERMS. 725 Leucantheiimm) yields about 0.15 per cent, of a greenish volatile oil with the odor of chamomile and mint. CHICORY, the root of Cichorium Intybus, a perennial herb with blue or purplish ligulate florets, indigenous to and cultivated in Europe and naturalized in the United States (Fig. 395), is used in medicine as well as in the preparation of a coffee substitute. The root is spindle-shaped, somewhat resembling Taraxacum, but is of a light brown color and the laticiferous vessels are arranged in radial rows in the somewhat thinner bark. It contains a bitter principle and a large amount of inulin. In the preparation of a coffee substitute the root is cut into rather large, equal pieces and roasted, after which it is ground to a yellowish-brown, coarse powder. The grains are heavier than water, imparting to it a yellowish-brown color. Under the microscope it is distinguished by the branching latex-tubes and rather short, oblique tracheae with rather large, simple pores. The SUNFLOWER (Helianthus animus) is an annual herb indig- enous to tropical America and extensively cultivated. The plant is grown on a large scale in Russia, Hungary, Italy and India for its fruits, which yield a fixed oil resembling that of cotton seed. The achenes (so-called seeds) are obovate, flattened, externally black or with alternate white and black stripes, the pappus con- sisting of two deciduous, chaffy scales. Sunflower seed-cake is readily distinguished by a few of the fragments of the epicarp, with the characteristic twin, unicellular, non-glandular hairs and large, oblique, but rather short, sclerenchymatous fibers. Besides 40 per cent, of a fixed oil, the seeds contain a peculiar glucosidal tannin, helianthic acid, which is colored deep green with ferric chloride and yellow with alkalies. The root contains inulin : the shoot asparagin, and the fresh pith about 1.5 per cent, of potas- sium nitrate. The pith has been used in the preparation of MOXA, a combustible vegetable material which burns without fus- ing and is used by the Portuguese to destroy any deep-seated inflammation. The pith of various species of Artemisia, which also contains considerable potassium nitrate, furnishes the Chinese Moxa. JERUSALEM ARTICHOKE (Helianthus tuberosus) is a large, coarse, pubescent herb with yellow ray-florets, which is indigenous 726 A TEXT-BOOK OF BOTANY. to the Middle United States and sometimes cultivated. The tubers, which resemble artichokes, are more or less elongated or pear-shaped, reddish-brown, somewhat annulate, and internally white or reddish. They have been used as a substitute for pota- toes and contain about 16 per cent, of the following carbohydrates : Inulin, pseudo-inulin, inulenin, saccharose, helianthenin, and syn- antherin. In early spring with the development of the tubers there is formed a small quantity of dextrose and levulose. The Globe artichoke of the gardens (Cynara Scolymus) is a hardy perennial and is valued on account of the fleshy involucral scales and torus, which are edible. The POLLEN of a number of plants of the Composite, as rag- weed (Ambrosia), golden-rod (Solidago), aster and chrysanthe- mum, is said to be responsible for the autumnal cold, known as HAY FEVER. A similar disease is produced in spring and early summer by the pollen of certain grasses. It has been found that the pollen grains of these plants contain a highly toxic substance, belonging to the toxalbumins, which is the cause of the disease. By inoculation of rabbits, go-ats and horses with this toxalbumin a serum containing an antitoxin is obtained which neutralizes the pollen toxin and protects those who are susceptible to hay fever from its attacks. In practice the serum is prepared by injecting the toxalbumin subcutaneously into horses, the serum being known in commerce as POLLANTIN (Fig. 398). The pollen of the following plants is toxic : aster, barley, chrysanthemum, convallaria, corn-flower, golden-rod, grasses, honeysuckle, oats, cenothera, ragweed, rice, rye, spinach, wheat, and zea. The constituents of rye pollen are 86.4 per cent, of organic matter, 10.2 of water, and 3.4 of ash. The organic matter consists of 40 per cent, of toxic substances, 3 of fixed oil, 25 of carbohydrates, and 18 of a non-albuminous substance. The num- ber of pollen grains per gram varies in different plants : from Indian corn being 7,000,000, of rye 20,000,000, of golden-rod 80,000,000, and of ragweed 90,000,000. The flowers of the Japanese chrysanthemum " Riuno-kiku ' (Chrysanthemum sincnsc japonicum) yield 0.8 per cent, of a volatile oil containing an optically inactive crystalline iso-camphor. CHAPTER VI. CULTIVATION OF MEDICINAL PLANTS. WHEN the forests and woods were full of wild medicinal plants that could be easily gathered, there was hardly an incentive to consider the farming of them. Now that they are becoming scarcer, the need is especially apparent. Our interest in the culti- vation of medicinal plants, however, is not primarily because there is a growing scarcity of the sources of supply, but in order that drugs of uniform quality and increased value may be had. For- tunately, there is a tendency on the part of some manufacturing pharmacists to concentrate their efforts upon a few plants yielding drugs and to study them in relation to their active principles throughout different periods of the season. In addition to these actual experiments, there are numerous inquiries made regarding the possibilities of the successful farming of medicinal plants. These inquiries come from various people who, for one reason or other, would like to get into country life and have some definite work to do. Many of them have never had any practical experi- ence in growing plants other than taking care of a garden plot. Nearly all know nothing of the commerce of drugs and have no idea of the problems connected with the disposition and marketing of them. Fortunately, some experiments have been conducted and there is some general information as to how one should proceed in the work. However, it must be said at the outset, no one can grow medicinal plants without having some training and special education for it ; and unless one is familiar with the prac- tical conditions of trade, that is in regard to* the markets and prices paid for drugs, even though successful in raising a good crop, one may not be able to dispose of it. It is very difficult to lay down any one rule that can be invariably followed on this sub- ject. In fact, very little work has been done to enable us to draw other than very broad conclusions. The first thing to be consid- ered is locality. Of course, tropical plants would not grow in the temperate zone, nor mountainous plants at the seaside, although even here there are exceptions that only experiments can show. 727 728 A TEXT-BOOK OF BOTANY. Then again, there are plants which grow only in the rich woodland soil, while others grow in barren soil in open places. Some plants require special kinds of soil, as Atropa Belladonna and Cannabis sativa, which do not seem to reach a high state of cultivation except in a calcareous soil. On the other hand, the plants of the Ericaceae are peculiar in that they require an acid soil (pp. 250, 656). In beginning this work in a new locality it is very important to make a rather careful survey of the plants growing wild, or those which have become naturalized. It would be safe to say that within certain limits, if there are a number of genera of any family well represented that has some of the habits of the plant with which one desires to experiment with, there is a probability that it may be grown successfully. This can be ascertained to some extent by the nature of the plants that are brought under cultiva- tion. For instance, digitalis might be grown very successfully in localities where it is cultivated and has become naturalized. By a priori reasoning, in the cultivation of licorice, the ideal location for growing the plant would be in the West and North- west where the wild licorice, Glycyrrhisa lepidota, is indigenous. In addition, it is necessary to study the best ways of propagating the plant one wishes to grow. Sometimes this is by means of seeds, as in belladonna and digitalis ; at other times it is by propa- gation of rhizomes, as hydrastis and glycyrrhiza ; or again by root-stocks or prostrate stems, as in the mints. Sometimes both seeds and cuttings may be used, as in the case of hydrastis. PLANTS GROWN FROM SEEDS. — A large number of plants can be grown from seeds, and when they are grown in this manner, espe- cially in a temperate climate, where the growing season is rather short, it is necessary to begin the germination of the seed early in the spring. This must be done in the house or under conditions where there is some protection. They may be sown either in small boxes or seed pans, in which the soil is quite sandy or made up largely of broken granitic rock (Fig. 400), and which must be clean and free from organic matter that is likely to mould. The seeds should not be planted too deep, and the boxes or pans should be covered with glass so as to condense or hold moisture. Of course, where there is the necessary attention, so far as keeping trie earth moist is concerned, this can be dispensed with. The CULTIVATION OF MEDICI XAL PLANTS. 729 FIG. 400. Digitalis Seedlings in seed pans, ready to be transplanted into plant flats. This is the first step in the propagation of Digitalis. — From the Experimental Farm of EH Lilly & Company, Indianapolis, Ind. 730 A TEXT-BOOK OF BOTANY. time required in germination will vary considerably. Many seeds will germinate well within two weeks ; usually probably four or five weeks are necessary. Occasionally some seeds, as with roses, may require a year or two. The present tendency is to shorten the period of germination in several ways. The simplest, possibly, is to place the seeds in water for 24 hours. If the seed-coat is more or less lignified and non-porous, boiling water is poured upon them, or some special treatment may be given, as the use of dilute ;r.y.;--.-v • '.: • - ••••:••••:•: • • FlG. 401. Digitalis Seedlings in plant flat, three months after transplanting from seed pans. These plants are now ready to be transferred to cold frames. — From the Ex- perimental Farm of Eli Lilly & Company, Indianapolis, Ind. or even concentrated mineral acids. For instance, in the culti- vation of Paraguay tea or mate, for many years it was found that the seeds would not germinate unless they had previously passed through the alimentary tract of certain birds. Later it was found that the same results could be obtained by placing the seeds in solu- tions of hydrochloric acid. Miller reports that he has obtained good results in the case of belladonna by first placing the seeds for 30 or 40 seconds in concentrated sulphuric acid. The germination of seeds may also be hastened by certain mechanical means. These are employed when the seed-coat is unusually thick and not easily CULTIVATION OF MEDICINAL PLANTS. 731 penetrated by the moisture; or if the seeds are large, they may be filed in one or two places ; when they are small they may be shaken with sharp, angular sand until the exterior is somewhat roughened. After the seedlings have put forth a few leaves they are then set out in suitable boxes known as flats (Fig. 401) which contain a soil having a fair amount of nutriment. The plants must be watched at this point to see that there is no damping off and loss by reason of attacks by soil micro-organisms. FIG. 402. Cold frames for use in propagating such plants as Digitalis, Belladonna, Henbane, etc. The young seedling plants are transferred from the greenhouse to these cold frames in late spring for the purpose of hardening them before transplanting to the open field. — From the Experimental Farm of Eli Lilly & Company, Indianapolis, Ind. Should there be a damping off and loss of seedlings some method should be employed to overcome it. Recently the De- partment of Agriculture has utilized dilute sulphuric acid, which Kraemer has shown is the active principle produced whenever sulphur is used in the greenhouse, for the destruction of insect pests, as well as the blights due to fungi and other micro- organisms. The plants are allowed to grow in the flats until they have developed a good root system and have produced a shoot with 3 or 4 leaves. They are then transferred to cold frames (Fig. 402), where they remain until they are acclimatized or hardened 732 A TEXT-BOOK OF BOTANY. sufficiently to be planted directly in the soil. This transferring should be done not later than the early part of May. The structure and use of the cold frame is perfectly familiar to the practical gardener. Sometimes the individual plants are removed from the flats and placed directly in the soil of cold frames. This may give them a temporary setback, as the roots are more or less disturbed FIG. 403. A general view of the testing and breeding of medicinal plants at the Experi- mental Farm of Eli Lilly & Company, Indianapolis, Ind. by the operation, but if the experiment in the cold frames is to be continued considerable time will be saved. If the plants are to be transplanted out of doors it is desirable that this should be done as soon as possible after the last days are over for the possibility of frost. The plants are arranged in rows and set sufficiently far apart so the maximum crop per acre can be obtained (Figs. 403-407), and also that weeds may be pulled out and the ground worked over. The above outline given may be used for the propagation of CULTIVATION OF MEDICINAL PLANTS. "33 most plants by seedlings. Some plants are rather easily grown if care is taken with their culture, as digitalis and belladonna. Other plants, like hyoscyamus, are with some difficulty cultivated, and very few persons, even seedsmen, are uniformly successful in growing aconite. It should also be stated that there are a number of plants yielding medicinal products which are grown from seeds and require no more care than the usual garden plants. Among these are calendula, Chrysanthemum roscum, echinacea, FlG. 404. Harvesting a unit test plot of first-year Digitalis. — From the Experimental t Farm of EH Lilly & Company, Indianapolis, Ind. and a number of others grouped under sweet, pot, and medicinal herbs. PROPAGATION BY CUTTING.- -This is a common method of propagating plants, being extensively employed by florists. A cutting is a severed portion of a stem having one or more nodes or buds. They are derived either from over-ground shoots, as in carnation, rose, geranium, and coleus, or, where the plant produces root-stocks or rhizomes, they are made from these rather than from the over-ground shoots. Not all plants can be propa- gated equally well from cuttings. Some plants are readily propa- 734 A TEXT-BOOK OF BOTANY. gated in this way, as the willows, the twigs of which, when they fall off or are broken off, frequently take root in the moist soil. Other plants, like the oak, are very difficult to grow from cuttings. In propagating plants from rhizomes the latter are cut into pieces, each of which has one or two buds, and these pieces are planted. Among the medicinal plants which have been grown from cuttings of rhizomes are licorice, peppermint, hydrastis, and ginger, but it is likely that all plants which produce rhizomes can be readily FIG. 405. Goldenseal (Hydrastis canadensis) farming in a natural woodland glade. — From Wellcome Materia Medica Farm near Dartford, England. propagated in this manner. Cuttings of over-ground stems are made from the growing parts of branches, and it is necessary to have them of such a length that at least one node may be placed in the soil. These are at first planted in micaceous soil or river sand, which should be kept well moistened. It is desirable that the leaves be as few as possible, so as to reduce the transpiring surface until the young roots have been formed, which may take several weeks or several months. Usually the lower leaves should cut off entirely, while the others may be partially trimmed. The CULTIVATION OF MEDICINAL PLANTS. 735 cuttings should also be protected from strong light, as this tends to increase transpiration, and also* guarded against a dry atmos- phere, which may be accomplished by covering them with glass, particularly during the day, when the weather is dry. Cuttings of hard wood plants intended for outdoor culture should be made in the fall. They should be 6 or 8 inches in length, kept covered with sand in a suitable place during the winter, and planted in the spring. FIG. 406. Goldenseal (Hydrastis canadensis) farming under an artificially constructed shade. — From Wellcome Materia Medica Farm near Dartford, England. In the case of both ginseng and hydrastis, one-year-old plants are often supplied by growers, and, though this is not always desir- able, yet there are conditions where, for experimental purposes, they may be used. It should be emphasized that it is not merely a matter of getting rhizomes or young plants, but a very careful study should be made of the conditions governing soil and light, and which favor the maximum returns from the crop (Figs. 405- 407). Caution should be exercised in the use of manure for in- creasing the yield of the crop as well as the plant constituents. 736 A TEXT-BOOK OF BOTANY. CULTIVATION OF MEDICINAL PLANTS. 737 The method for producing new varieties is by hybridization, or cross-pollination, of different related species or varieties (Fig. 403). The offspring is known as a HYBRID, and has a blending of the qualities or characters of the two parent plants. This method is mostly employed by florists who desire to produce some new or striking flower, or by horticulturists who desire to establish some new quality or transfer a desirable quality from a foreign plant to one which is adapted to a given locality. The method has not been largely employed in the cultivation of medicinal plants, except in the case of cinchona, where it is claimed that the barks richest in alkaloids are the direct result of hybridization and selection. By transplanting and special methods of treat- ment, as that of mossing, the alkaloidal percentage has been in- creased from 8 per cent, to 10, whereas by hybridization the amount of total alkaloids has reached as high as 16 per cent., about three- fourths being quinine. COLLECTING AND DRYING OF DRUGS.- -The time of the COLLEC- TION of vegetable drugs is of prime importance, and, while it may not be possible to make extended generalizations, still, the fol- lowing rules for the collection of various drugs may be given : 1 i ) Roots, rhizomes, and barks should be collected immedi- ately before the vegetative processes begin in the spring, or immediately after these processes cease, which is usually in the fall. (2) Leaves should be collected when photosynthetic processes are most active, which is usually about the time of the develop- ment of the flowers and before the maturing of fruit and seed. (3) Flowers should be collected prior to or just about the time of pollination. (4) Fruits should be collected near the ripening period, i.e., full grown but unripe. (5) Seeds should be collected when fully matured. It should be emphasized that these are very general rules for the guidance of the collector, and that when one is farming drug plants this question becomes exceedingly vital, as not only do the constituents vary at different times during the season, but there is considerable variation in the amount of drug obtained. The exact information regarding the proper time of gathering any 47 A TEXT-BOOK OF BOTANY. specific drug can be obtained only by collecting it at different times during the season, assaying it and making preparations from it. Experiments thus far seem to show that belladonna leaves collected in July and August show a higher toxicity than those gathered in September or October. It is quite possible that after the removal of the leaves high in alkaloidal content in July, another crop can be obtained by October. It is important to bear in mind with some drugs that a very slight difference in time of gathering and manner of drying, great variation of the active con- stituents may be found, as with many of the Composite flowers. It is only when they are in the bud condition, as in the case of insect flowers, and santonica, that they show the highest amount of active principle. Again, depending on whether an article is gathered to be put upon the market or whether the active prin- ciples are to be isolated, as in the manufacture of the essential oils, different methods are followed, depending upon the nature of the plant and what previous experiments have demonstrated should be followed. For instance, while in the preparation of oil of peppermint the herb is first dried, yet in other cases the col- lected material must be previously macerated in order to obtain the largest yield of oil, as with those plants yielding volatile oils containing either cyano-benzaldehyde or methyl-salicylate. Too much attention cannot be given to the entire question of the harvesting of the crop and proper methods of drying, and, of course, again, depending upon the locality, different methods will be followed. There are some places at certain times where it would be quite possible to dry the drugs out of doors. In other situations it would be necessary to dry them in barns and even in specially constructed drying ovens where artificial heat would be employed. The drying of leaves, flowers, and seeds is com- paratively simple and can usually be rather quickly performed without any special preparation. In the case of roots and fleshy fruits the drying should be under special protection, and is facili- tated more or less by slicing or comminuting the article. In some drugs, in addition to drying, there is a curing process that takes place. By this process of fermentation the active con- stituents are developed. Among the drugs treated in this manner the following may be mentioned : tobacco, vanilla, gentian, CULTIVATION OF MEDICINAL PLANTS. 739 guarana, digitalis, the Solanaceous leaves, etc. In some cases the increase in quality can be determined by the assay of some one constituent, but in other cases the acquired value, like that of teas, wines, and tobacco, cannot be determined by an assay process and yet can be detected by the expert. It has already been pointed out that plants contain a large proportion of water, and when they are collected and dried there is necessarily considerable loss. The loss is greater in the case of herbaceous plants, where the yield of crude drug is only about 10 per cent., as in eupatorium and stramonium. Roots and rhi- zomes yield on an average from 20 to 30 per cent, of dried drug. In some cases, as in hops, the yield of dried drug is over 60 per cent., and in fruits and seeds there is very little loss. RELATIVE VALUE OF DRUGS FROM CULTIVATED AND WILD PLANTS. — For some years it has been a question whether the activity of drugs obtained from cultivated plants is equal to that of those derived from wild plants. We find in some of the foreign pharmacopoeias the specific statement that certain drugs, as digitalis, belladonna leaves, and belladonna root, must be derived from wild plants. This would naturally lead to the infer- ence that wild plants are better, and yet it may be that this provision was made with the intention of securing uniformity of drugs rather than because the materials from wild plants are superior. In 1907 Rippetoe conducted some experiments in Vir- ginia which showed that cultivated plants of belladonna yielded both leaves and roots which were equal, if not superior, to the average drug on the market. As this work was done without any particular care and in a limited way, it was more than gratifying to those who were especially interested in this subject. Carr has shown by careful comparative experiments that cultivated plants of belladonna contain a little more alkaloid than do the wild plants. The investigations of Sievers also point to a similar conclusion. Sievers has also shown that the percentage of alka- loids in the leaves of different cultivated plants is exceedingly large, and that plants high in alkaloids will continue to breed plants high in alkaloids, so that by mere selection a better com- mercial article may be produced. Coming to the question of digitalis, there are some very interesting results. Hale, for in- 740 A TEXT-BOOK OF BOTAXY. stance, showed that cultivated digitalis leaves yield a much higher potency than those obtained from wild-grown plants, and yet he concludes that it is doubtful whether the fact that they were cultivated had anything to do with the high activity. One of the most valuable facts brought out in connection with these experi- ments is that the leaves of one-year-old plants seem to have as great toxicity as those of the two-year-old plants. Hale distinctly states that ' first-year leaves are not necessarily weaker than second- FlG. 408. Atropa Belladonna, first year's growth from seed planted January ist. Photograph in July of the same year. — From the Experimental Farm of Eli Lilly & Com- pany, Indianapolis, Ind. year leaves, and might be used in preparing assayed digitalis prepa- rations." This means that one does not have to wait two years before securing a crop, so that practically one can obtain twice the quantity of the drug during the same period. There may be some instances during this experimental stage which might seem to indicate that certain external conditions, such as climate as well as soil, have a very great influence in the growing of plants of exceptional value. In the case of American-grown cannabis, Eckler and Miller have shown that repeated plantings CULTIVATION OF .MEDICINAL PLANTS. 741 from carefully selected plants of American and Indian cannabis have failed to yield, when in cultivation near Indianapolis, a product testing- over 65 per cent, of the active value of good Indian-grown drug, and that the majority of the plants tested 50 per cent, and even less. FIG. 409. Form of American Cannabis developed by F. A. Miller. Such forms are obtained by selection and result in strains that are better adapted to modern methods of agriculture and from which the collection of the pistillate inflorescence is greatly simplified.— From the Experimental Farm of Eli Lilly & Company, Indianapolis, Ind. Experiments conducted near Timmonsville, S. C., by the U. S. Department of Agriculture have shown that in that locality a drug of a somewhat higher degree of potency can be grown. Of course, it is well known that the hemp plant is grown extensively for fiber in Kentucky and other parts of the middle West. This 742 A TEXT-BOOK OF BOTANY. may be due in large part to the fact that it requires a limestone soil, and in practice the most favorable results are obtained where there is an underlying bed of blue limestone. Sufficient has been said to show that success will attend the cultivation of medicinal plants, and indeed, by a priori reasoning on the basis of other FIG. 410. Form of American Cannabis developed by F. A. Miller. Such forms are obtained by selection and result in strains that are better adapted to modern methods of agriculture and from which the collection of the pistillate inflorescence is greatly simplified. —From Experimental Farm of Eli Lilly & Company, Indianapolis, Ind. agricultural efforts, one would expect that medicinal plants could be grown with the same certainty of increasing the yields of any particular constituent or quality that might be desired. Indeed, the history of the sugar beet industry has been duplicated in the work on Cinchona, and the same thing can be said with regard to any other plant that man desires to conserve and cultivate. There CULTIVATION OF MEDICINAL PLANTS. 743 are no insurmountable obstacles in this work, and there are no in- tricate processes to be solved before success results. There are merely a few underlying principles that must be adhered to, and by persistent effort and with a full understanding of market con- ditions success must crown the efforts of anyone who undertakes FIG. 411. A seedling plant of Digitalis about six months old. this work. What has been done in the selection of fruits and vege- tables can be equally well accomplished in drugs with the proper incentive. PROGRESS IN THE UNITED STATES. — \Ye can scarcely appreciate that, while the development of medicinal plant culture has been 744 A TEXT-BOOK OF BOTANY. an exceedingly slow one, yet as a matter of fact, by reason of some of the products being more extensively used, as in the case of hops, it is one of the oldest agricultural industries in the United States. The history of the cultivation of hops is very similar to FIG. 412. Cannabis sativa: Young plant prrown from seed found in the drug Cannabis indica. the experience with other medicinal plants. For instance, it was grown in Virginia with poor results, and in Vermont and Massa- chusetts, where it was very successful. By virtue of the success obtained in the New England States it was, in the early part of the last century; introduced into New York State and later spread CULTIVATION OF MEDICINAL PLANTS. 745 into some of the Middle States, as Michigan, Wisconsin, Indiana, and Ohio. Since that time the cultivation has been extended to FIG. 413. Seedling plants of Erythroxylon Coca (A) and Eucalyptus globulus (B). some of the States on the Pacific coast, notably Oregon, Washing- ton, and northern California. The peppermint industry shows a similar history. This indus- try was first developed in Wayne County, New York. Later it 746 A TEXT-BOOK OF BOTANY. spread into Michigan, Ohio, and some of the Southern States, and by reason of the more favorable climate and soil conditions in Michigan the industry here has outstripped that of even New York State, being practically abandoned in Ohio and the other States. The men connected with the Division of Botany of the United States Department of Agriculture have always mani- fested a keen interest in the possibilities of the cultivation of medicinal plants, and have done what they could to encourage interest in this subject, and the records show that they have sup- plied information as it might be needed by those disposed to take up the work in a practical manner. The development of the tea industry in North Carolina is one of the most creditable pieces of work of the National Govern- ment. Bulletin No. 234 of the Bureau of Plant Industry, on " The Cultivation and Manufacture of Tea in the United States," by George F. Mitchell, should serve as an inspiration to anyone contemplating drug culture. If a plant of this kind can be grown successfully here and the technique of manufacture developed to such an extent that the cultivation at Pinehurst, North Carolina, has become remunerative, there is no question but that within reasonable limits nearly any plant except the strictly tropical ones can be successfully grown in the United States. Without doubt, the camphor industry will become successful in some of the Southern States. Nearly fifty years ago, when the price of camphor was very high, the government started some experiments in Florida in the growing of the camphor tree. These experiments were subsequently abandoned, as there was hardly any likelihood of anyone being interested in this commercially on account of the low price of camphor. During the past few years, however, interest in this culture has been revived in Florida and southern Georgia by reason of the fact that frosts destroyed the citrus fruits and the landowners began a search for other possible crops which would not be- so injured. Circular No. 12, Division of Botany, United States Department of Agriculture, shows just what can be done for the successful cultivation of this tree in the Southern States, and some recent experiments of the government show that by utilization of leaves and twigs there are great possi- bilities in the economical manufacture of camphor in the United States in spite of the high price of labor. CULTIVATION OF MEDICINAL PLANTS. 747 Owing to the fact that essential oils are used in such large quantities it is quite likely that the cultivation of many of these plants may be made successful, providing at the same time that suitable apparatus for their distillation is also installed upon the farms. By reason of the fact that the cultivation of chicory is a per- manent agricultural industry in nearly all of the countries having a temperate climate in Europe, experiments have been conducted in the L^nited States in a small way, and these have led to the con- clusion that it may be successfully cultivated in those States where the sugar beet industry has flourished. As a summary, the following general points might be held in mind by those who desire to take up the cultivation of medicinal plants : In the first place, he ought to determine whether there is a market for any drug under consideration, and this can only be obtained by personal inquiry and investigation, as not even any of the government publications give this information. In the next place, if one is satisfied that it is worth while to take up the cultivation of any particular plant, its geographi- cal range should be studied, both as to where it is indigenous and where it has become naturalized. The literature should be gone over not only for facts regarding the cultivation and distribu- tion of the particular plant in view, but also of some of the related plants. At the same time that these preliminary studies are made, a careful survey should be taken of the plants which are indigenous and under cultivation in the particular locality where one is pro- posing to locate the farm. Then, of course, everything should be done on a small scale at first. If there is no information available, then he must, on the basis of the general principles laid down for the cultivation of medicinal plants, proceed with their culture, conducting parallel experiments with propagation by both seeds and cuttings. Then when the crop is harvested he must, by analytical and other means, satisfy himself as to the value of his product com- pared with the commercial article, and with these facts in hand submit specimens and request quotations from the dealer in crude drugs, and the wholesale druggist. On this basis he will arrange 748 A TEXT-BOOK OF BOTANY. for all future crops with some certainty as to their market value. Experience has shown that cultivated crops command a higher price than the drugs obtained from wild plants, even though their superiority cannot always be demonstrated by analytical means. For instance, no one is trying to determine by an analytical process whether any given lot if tobacco, tea, or cofTee is of superior value, and yet the competent dealer and the discriminating public even recognize the qualities of the grades that are offered. This is even more marked with the products that have been derived thus far from cultivated medicinal plants, and are appreciated by some pharmacists and physicians. BIBLIOGRAPHY. CULTIVATION OF BELLADONNA: A. F. Sievers, Amcr. Jour. Pharm., March and November, 1914; Francis H. Carr, Ibid., November, 1913; F. A. Miller, Ibid., July, 1913. CULTIVATION OF DIGITALIS: E. L. Newcomb, Amcr. Jour. Pharm., No- vember, 1911 ; John A. Borneman, Ibid., December, 1912; F. A. Miller,. Ibid., July, 1913. CULTIVATION OF HYDRASTIS : John Uri Lloyd, Proc. A. Ph. A., 1905, p. 307,. and in Jour. A. Ph. A., Vol. I, p. 5; Alice Henkel and G. Fred. Klugh, Circ. No. 6, Bureau of Plant Industry, U. S. Department of Agriculture; J. C. Baldwin, Amcr. Jour. Pharm., April, 1913. CULTIVATION OF GINSENG : George V. Nash, Bulletin No. 16, Division of Botany, U. S. Department of Agriculture. CULTIVATION OF EUCALYPTUS : A. J. McClatchie, Bulletin No. 35, Bureau of Forestry, U. S. Department of Agriculture. CULTIVATION OF PEPPERMINT: A. M. Todd, Proc. A. Ph. A., 1903, p. 277; Alice Henkel, Bulletin No. 90, Bureau of Plant Industry, U. S. De- partment of Agriculture. CULTIVATION OF CANNABIS SATIVA : C. R. Eckler and F. A. Miller, Amer- ] our. Pharm., November, 1912. CULTIVATION OF CAMPHOR: Circ. No. 12, Division of Botany, U. S. De- partment of Agriculture. CULTIVATION OF TEA: Bulletin 234, Bureau of Plant Industry, U. S. De- partment of Agriculture. CULTIVATION OF CHICORY: Bulletin No. 19, Division of Botany, U. S. Department of Agriculture. A number of valuable articles by Mitlacher and other members of the pharmacognostical department of the University of Vienna have been published in Zcitschrift fiir das landwirtschaftlichc J'crsuchswcscn in Oestcrreich since 1911. CHAPTER VII. MICROSCOPIC TECHNIQUE AND REAGENTS. MAKING OF SECTIONS. — In order to examine objects by means •of the compound microscope they must be relatively thin and transparent ; furthermore, they must be mounted in water or other mounting fluids. In material consisting of single cells, or, at most, a layer of a few cells, the specimen may be mounted directly in water. This manner of mounting may also be used in the exam- ination of pollen grains, hairs, and thin organs, as petals. Usually in the examination of the latter some clearing agent, as solution of hydrated chloral, is necessary in order to make the specimen trans- parent. As most objects consist of a large number of cells, it is necessary to examine small portions of them; and these are termed sections. They are made with a razor and c6rrespond to the shav- ings made by a carpenter's plane. As each object has three dimen- sions, it is necessary that three different kinds of sections be made. 1 i ) A transverse or cross section is one made horizontally through the object, therefore its plane lies at right angles to the long axis. (2) A radial-longitudinal section is one made at right angles to the cross section and it lies in the plane of the radius, so that in a dicotyledonous stem the section would be made parallel with the medullary rays. (3) A tangential-longitudinal section differs from the preceding in that it lies parallel to the outer surface of the object, or in a plane tangent to the cylinder. These several forms of sections are readily understood from the adjoining illus- tration (Fig. 414). Sections of roots, stems, barks, and many fruits and seeds can be made directly without embedding the material, and while sections can be made holding the material in the hand, between the thumb and three fingers, the hand microtome for holding the material may be used by those who are less experienced. In the sectioning of leaves and other material that is not firm, and fruits and seeds which are too small to hold in the hand, the material should be embedded in some substance which will hold it and give it stability. \Yhen the tissues are not too hard the 749 750 A TEXT-BOOK OF BOTANY. material may be placed between pieces of elder or sunflower pith. In some cases the making of sections is facilitated by moistening both the pith and the razor. In the case of seeds and fruits which are very small and at the same time very hard, as colchictim and mustard, it is best to use a velvet or fine grade of cork for holding the material. The cork is indented by means of forceps and the seed or fruit forced into the cavity. In the case of very delicate tissues, where the protoplasmic contents of the cells are to be studied, as in the ovaries of flowers, prothalli of ferns and other parts of the plant, where cell division is going on, the material should be embedded in paraffin or celloi- FIG. 414. Schematic presentation of the three types of sections: q, cross or transverse sec- l. radial-lonpitudinal section: /. tanpential-lonpitudinal sertion. — Aftpr \TPVPT- tion 4. bcnematic presentation of the three types of sections: q, cross or transverse s ; I, radial-longitudinal section; t, tangential-longitudinal section. — After Meyer. din, subsequently hardened, and sectioned by means of a finely adjusted microtome. DRIED MATERIAL. — Most of the vegetable drugs and some of the vegetable foods occur in commerce in a more or less dried condition, and in order to study them microscopically it is usually necessary to give them some preliminary treatment. With the majority of drugs, soaking in hot or cold water from a few minutes to a few hours will render them sufficiently pliable or soft for sectioning. After this the material is hardened by placing it in alcohol (60 to 70 per cent.) for a few hours or over night. It may then be sectioned and treated with special reagents or stains as desired. Very hard material, as the shells of nuts and MICROSCOPIC TECHNIQUE AND REAGENTS. 751 seeds, may be softened by soaking in solutions of potassium hydrate. SOME PRACTICAL SUGGESTIONS.- -The following are some of the rules which should be borne in mind by the student when using the microscope in the examination of microscopic material : 1. Always mount the sections (including powdered material) in water or other suitable reagent prior to examination ; never attempt to examine dry material except in special cases. 2. Use sufficient of the mounting medium or reagent to cover the specimen, but avoid an excess or more than will be held under the cover-glass. 3. Always endeavor to have the object properly illuminated by making use of the concave mirror. 4. Always be particular about having the eye-piece and objec- tives clean. 5. In examining a microscopic object, always use the low- power objective first. 6. The edge of a section is always the thinnest, and this part being the best for study, should be brought to the center of the field. 7. When the object is properly centered, raise the objective, swing it to one side, bring the high-power objective into its place, and cautiously lower it until it is brought to about the distance of a millimeter from the cover-glass. Then holding the slide with the left hand, the proper focus of the object is obtained by making use first of the coarse adjustment and then of the fine adjustment, the right hand being used for this purpose. In exam- ining the object always hold the slide with the left hand, and use the right hand for maintaining the proper focus by means of either the coarse or fine adjustment. 8. In all cases where practicable make drawings of the sections examined. 9. In some cases it is desirable to apply a reagent after the material has been mounted, as in the addition of an iodine solution to a section to determine the presence of starch, and this is accom- plished by placing a drop or two of the reagent, by means of a pipette or dropper, near the edge of the cover on one side and 752 A TEXT-BOOK OF BOTANY. taking up the excess of liquid by temporarily placing a piece of filter paper on the opposite side (Fig. 415). AIR-BUBBLES. — The beginner in the use of the microscope is often confused by the presence of air-bubbles, mistaking them for portions of the material under examination, as starch grains, oil-globules, or even the cells themselves. While it is not prac- PIG. 415. Method of applying reagent to material already mounted, g, pipette; f, filter paper. ticable to avoid their presence entirely, their identity may be determined by the manner of focussing upon them. When focussing above on an air-bubble it always appears dark (Fig. 416, C) , but when the focus is lowered, it becomes lighter (Fig. 416, D) ; while in the case of an oil-globule or starch grain the reverse is true, i.e., it is lightest when the focus is above (Fig. MICROSCOPIC TECHNIQUE AND REAGENTS. 753 416, £) and darker when the focus is lowered (Fig. 416, F). To obviate as much as possible the formation of air-bubbles, the edge of the cover-glass should first be applied to the liquid on one side and then allowed to drop upon it. When particular care is required, a pair of forceps may be used for holding the cover and lowering it gradually. B FIG. 416. Diagrams showing the difference between an air-bubble and an oil-globule in different foci: When the focus is above, as at A, the air-bubble (C) is dark gray and the oil-globule (E) light gray. When the focus is at the lower portion, as at B, the air- bubble (D) is light in the center and the oil-globule (F) dark gray. The same optical effects as are obtained with oil-globules are observed with cell walls, starch grains and crystals. Frequently also simple pores in the cell-wails are mistaken for cell-contents, and sometimes even the lumen of the cell has been mistaken for a prism of calcium O'xalate. The beginner will therefore find it an advantage to study the simple pores in the pith cells of elder or sassafras (Fig. 132). In sections show- ing either the upper or lower wall of the cells, the pores appear as circular or elliptical markings, which may be mistaken for cell- 48 754 A TEXT-BOOK OF BOTANY. contents, but which in focussing upon them are seen to be optical or microscopical sections of the pores. MICROMETRY OR MICROSCOPIC MEASUREMENT. — In the micro- scopic study of any substance a knowl- edge of the comparative size of the elements is often of much help in deter- mining the identity of material under examination, and for this reason the student should early learn to measure the characteristic elements, or those showing a variation in size in different plants, as starch grains, calcium oxalate crystals, diameter of cells, thickness of cell-walls, etc. The method best adapted for this work is that involving the use of a micro- metric scale which is placed in the eye- piece and known as the ocular micrometer. But to determine the value of the ocular micrometer it is necessary to use another scale known as the stage micrometer. The stage micrometer, as its name indi- cates, is used on the stage, and when placed in juxtaposition to an object indi- cates its size. However, it is obviously impracticable always to place an object alongside of the scale, and hence in prac- tice the ocular micrometer is used, the value of the divisions of which are PIG. 417. Section of micro- r1ptprrninpr1 Vw rntmnarisnn with tlin<;p nf scope showing the relation of aeterrnine(1 DY COmpar HI WlLfl the ocular micrometer (o) and fk cfnrrp rmVrnmptpr ( Ficr Af7\ TViP the stage micrometer (s). As tne Stage ^ r Ig . 41? )• value of the divisions of the ocular scale - varies for different objectives, eye-pieces and tube lengths, hence it is necessary to - on wScPhhrhtmociLeScProeme: ascertain the value of the divisions for the different optical combinations and tube lengths employed. The stage micrometer is usually divided into tenths and hundredths of a millimeter, and the millimeter being equivalent to 1000 microns (the micron being indicated by the MICROSCOPIC TECHNIQUE AND REAGENTS. 755 Greek letter /*), the smaller divisions are equivalent to 10 microns (IO/A). For example, suppose, using a low-power objective, that 10 divisions of the ocular scale equal 20 of the smaller divisions of the stage micrometer. Thus, 20 divisions of the stage micrometer are equivalent to 20 times IO/A , or 200 /* ; then, since 10 divisions of the ocular scale equal 20 divisions of the stage micrometer, one division of the ocular scale is equivalent to i/io of 200 /*, or 20 //.. Or, using the high-power objective, we may suppose that 80 divisions of the ocular scale equal 24 divisions of the stage micrometer. Thus, I division of the ocular micrometer is equivalent to i, 80 of 240 p., or 3 /*. Then, if an object has a diameter covering 3 divisions of the ocular micrometer, its diame- ter is equivalent to 3 times 3 /x (the value of one division), or 9 /.i. REAGENTS.- -The reagents that have been recommended for microscopical work are quite numerous, and, while nearly all oi them may have more or less special merit, the number of reagents actually required in practice is fortunately quite small. It is important that the student recognize the necessity for a thorough understanding of the structure of the material under examination rather than place too much dependence upon the effects produced by reagents ; in other words, the study of struc- ture should precede the use of reagents, particularly stains, when it will often be found that the latter can be dispensed with entirely. The chemicals that are employed in microscopical work, either as reagents or for other purposes, may be classified as follows : (i) Preservatives, (2) Fixing and Killing Agents, (3) Harden- ing and Dehydrating Agents, (4) Clearing Agents, (5) Stains, and (6) Special Reagents. PRESERVATIVES are substances used to preserve material which is to be examined. The most important of these are alcohol ( from 40 to 95 per cent.) and formalin [2 to 6 per cent, aqueous or alcoholic (60 per cent, alcohol) solution], the latter of which is considered advantageous in the preservation oi specimens contain- ing coloring substances, as leaves, flowers, etc. Almost any anti- septic of the proper strength may be used as a preservative. FIXING or KILLING AGENTS are more especially employed in the study of the protoplasmic cell-contents, where by their use the life-processes of the cell are brought to a sudden termination, 756 A TEXT-BOOK OF BOTANY. the object being to fix the contents in a condition approaching as nearly as possible the normal living state. In order to carry out this operation successfully, the living specimen must be placed in the fixing or killing agent as soon as collected, and if the specimen is large it should be cut into small pieces. The following are some of the common fixing agents : Chromic acid in 0.5 to I per cent, aqueous solution ; osmic acid in i to 2 per cent, aqueous solution ; Flemming's mixture, which is an aqueous solution of chromic acid (0.25 per cent.) containing o.i per cent, of osmic acid and o.i per cent, of acetic acid; picric acid in concentrated aqueous or alcoholic solution ; picric-sulphuric acid, a concentrated aqueous solution of picric acid containing 2 per cent, by volume of sulphuric acid; and mercuric chloride (corrosive sublimate) used in o.i to I per cent, aqueous or alcoholic solution. HARDENING or DEHYDRATING AGENTS are those substances which are employed for the purpose of hardening the specimen so as to facilitate sectioning and for removing the water, which would interfere with its examination. Alcohol is to be regarded as the principal hardening or dehydrating agent, and considerable care is necessary in its use; the specimen is treated successively with alcoholic solutions of gradually increasing strength, begin- ning with a 35 per cent, solution, in which the specimen is kept for twenty- four hours ; then it is placed in 50 per cent, alcohol for from six to twenty-four hours, and then in 70 per cent, alcohol, in which it may be kept until ready for use. In order to avoid shrinking of the material at this stage, it may be kept in a solu- tion of alcohol and glycerin, or oil of bergamot, or a mixture of xylol and paraffin. When the material is to be examined it should be removed to 85 per cent, alcohol for from six to twenty- four hours, then to 95 per cent, alcohol and absolute alcohol suc- cessively for the same length of time. Of the other dehydrating agents the most important are anhydrous glycerin, pure carbolic acid, and anhydrous sulphuric acid, the latter being used in a desiccator and not applied directly to the specimen. CLEARING AGENTS. — Most dehydrating agents are also clear- ing agents, because of the fact that the air and water in the speci- men are replaced by a medium having greater refractive proper- ties. Some clearing agents act chemically on the tissues and cell- MICROSCOPIC TECHNIQUE AND REAGENTS, 757 contents. Among the clearing agents most frequently employed are: Chloral in saturated aqueous solution, and chloral-glycerin solution (a solution of equal parts of glycerin and water saturated with chloral). Essential oils, as clove, turpentine, cedar, mar- joram, etc., are also useful for this purpose, particularly when the specimen is to be mounted in Canada balsam. STAINING AGENTS are those that produce more or less defi- nitely colored compounds with the cell-contents or -walls. They include: (i) the Aniline Dyes and (2) Non-aniline Stains. The aniline stains may be used in aqueous solutions, weak alcoholic solutions or strong alcoholic solutions, containing from I to 3 per cent, of the dye. The following are the aniline stains most frequently employed : Aniline blue, Bismarck brown, fuchsin, gentian violet, methylene blue, methyl violet and safranin. In addition to these, aniline hydrochloride or sulphate is used in what is known as Wiesner's Reagent, which is a 25 per cent, solution of alcohol containing 5 per cent, of either of these salts, a drop of either hydrochloric or sulphuric acid being used with a drop of the solution, according as the hydrochloride or sulphate has been used. LOFFLER'S METHYLENE BLUE.- -This reagent is prepared by adding 30 c.c. of a concentrated alcoholic solution of methylene blue to 100 c.c. of water containing 10 milligrams of potassium hydrate. ZIEHL'S CARBOL-FUCHSIN. — This solution is prepared by add- ing 15 c.c. of a concentrated alcoholic solution of fuchsin to 100 c.c. of water containing 5 grams of carbolic acid. ANILINE DYES are usually employed in concentrated aqueous solution, but owing to the difference in solubility of the dyes the solutions vary in strength. Saturated solutions of eosin or gen- tian violet may be prepared by dissolving i gram of the dye in 100 c.c. of water, while to make a saturated solution of methylene blue requires 0.400 Gm. of the dye to 100 c.c. of water. Some investigators prefer to replace the distilled water with aniline water, which is prepared by adding about 3 grams of anilin oil to 100 c.c. of distilled water. REAGENT BOTTLE FOR STERILE SOLUTIONS.- -The solutions of the aniline dyes as ordinarily prepared deteriorate more or less rapidly and are usually made up fresh each time they are required 758 A TEXT-BOOK OF BOTANY. for use. These solutions, as well as other reagents that are prone to decomposition, may, however, be kept for months or even years by preparing them with care and keeping them in a special kind of bottle (Fig. 418). An ordinary bottle may be used, and is fitted with a rubber stopper perforated so as to allow the intro- duction of two glass tubes. These tubes are bent twice at right angles and the free ends directed downwards. One of the tubes is connected with an atomizer bulb and serves for forcing out the FIG. 418. Reagent bottle for sterile solutions. liquid. A small plug of absorbent cotton is placed in the tube at the point C, so as to filter the air. This may be improved by blowing a bulb in the tube for holding the cotton. The bottle should be sterilized before placing the solution in it, and the solu- tion should be made by adding the dye to sterile water contained in the bottle. The solution may be afterwards further sterilized by means of steam if this should be found necessary, as in this way only a perfectly sterile solution could be produced. MICROSCOPIC TECHNIQUE AND REAGENTS. 759 CO c O CO co -o > O 7^ "5" ^8 2.2-0 0 i w 8.? If d*° e.s-nB1 3-£ % O* ^. P ^ O r+ O* P S- I as D!N "B" §2 1^5 P to ^•3 C p O o ' g i-j »-•« r^ ^. ct- ^-. i-^ re S i re CL re 3 o o CL — a U Dissolve o i °"K era. Pale blue to bluish-black, depending upon the strength of reagent solving them =T) 3 '~ CL I The acid brings out the structure of the grains, the structure of the grains, finally dis- solving them C" M^ w co 0 C r-r i_j 3?C/2 •~3 3 <• 3" co P 5 re o ;r:2L § ^"ig ^'CL Brings out the structure Starch Grains zr p p ^* p r^q P r* 0 p C re 3' ft t/i gaS'S re 3 i-t re ,„ to |ES,| sulphate calcium Cause the separation of fine needles of <-!• CO ft- c^ 3 0 H o ^iS-cr^ Q Q| w" rf o> TO !f 3* Calcium Oxalate Crystals re CO i CO re > Swell and finally dissolve l!^r ?°Is O i-l i^ p ^ re o ti g CL ^ co r* 3 If I| ?» 2.2-n ^ co" purplish-rec become .j P D-2T o 3 c!^5'^ •" ^ M r^ ^ C£> t? 3 re O ST i rt- <-t o H •o -.^- coO,? o"g? 2. !^ H cn° i-t t-J ^ C -t H. cr o o 3* ^ ^1 ^ o* H 3 ^2." ^l ill 3 ^ 5T III P £ C/J If! CO cr i re ome £ ^ 3 B." w p P^TO cr,^. Lo* w o ^"5're o 3- re as i 1 n-9 CL «, op V) &»$ rt- IIS g||3 |l ^ c-t- K'w"/^ t»9 ^ W C sS w 3 re i ^ cr n (T *"~^ 4 fD ^ . re CD X O rn ^ c~^ o 0 P - 2To"re ^ 3 re ^ 0* t^re 2. ^ CO O T ^ 3 S-" ^ "TjCL &t O M "P ^ re o ti i o"s 3 ^ ST 5 3 3 — re 1-1 £ L/T ?" 3 re re 3 1 1 rt- ^ ^CL ^ °? CO Dissolve The wall become lavendei or violet v- re j3- re o fl> og-3 3 ° £L M 2. ^ ^J fp ^~* HH p csS P P .— -co . 2_ co CO <:+ P 3 p 3-3 OQ Parenchy CO CuW re j2u 3 Dissolve very slowly The walls become yellowish- brown -i H vj re 3- re_o ro V- W ^ re o B! a cot) Oo-la . /T) o ' — ' n* ?T Cr • — i <- O ii. re «-4 < a- O <-f H o^ o' cr^d £ 2. o 5- re » c 55 O •< ^0 II •< < re lill CD * ^T 0> O 2 to'2 S'M ^ < 3- CL > W a M o ? fD 5* EJ are §8 5-3 ||& 13 3 £ c+ j£. O re re £§ 0 ^ CL w w 760 A TEXT-BOOK OF BOTANY. The non-aniline stains give, as a rule, more reliable and con- stant results in the study of cell-walls, as in the roots, stems, and other parts of the plant, than the aniline stains. They include the following: BEALE'S CARMINE SOLUTION, which is made as follows: Mix 0.6 Gm. carmine with 3.75 Gm. ammonia water (10 per cent.) ; heat on a water-bath for several minutes ; then add 60 Gm. of glycerin, 60 Gm. of water and 15 Gm. of alcohol, and filter. GRENACHER'S BORAX-CARMINE SOLUTION. — Dissolve 2 to 3 Gm. of carmine and 4 Gm. of borax in 93 c.c. of water and then add 100 c.c. of alcohol (70 per cent.) ; shake and filter. When this stain is employed the sections are freed from an excess by the use of alcoholic solutions of borax or oxalic acid. HOVER'S PICRO-CARMINE SOLUTION is made by dissolving carmine in a concentrated solution of neutral ammonium picrate. A solution of carmine and picric acid is known as Picro-Carmine Solution. Carmine solutions give to cellulose, the nucleus and proteins a red color. CHLOR-ZINC-IODIDE SOLUTION, or Schulze's Cellulose Reagent, consists of anhydrous zinc chloride, 25 Gm. ; potassium iodide, 8 Gm., and water, 8.5 Gm., to which as much iodine is added as the solution will dissolve. This reagent gives a violet color with cell-walls containing cellulose. Of the cell-contents, starch is the only one which is affected by it, being colored blue. BOHMER'S H.EMATOXYLIN SOLUTION is prepared by mixing the two following solutions and filtering after allowing the mix- ture to stand for several days: (a) one part of a 3.5 per cent, alcoholic (95 per cent.) solution of hsematoxylin and (b) three parts of a 0.4 per cent, aqueous solution of potassium alum. DELAFIELD'S H.^EMATOXYLIN SOLUTION, which is also incor- rectly called " Grenadier's Hrematoxylin Solution," is made by mixing the following solutions: fa) Hrematoxylin 4 Gm., alcohol 25 c.c., and (b) 400 c.c. of a saturated aqueous solution oi ammo- nia alum ; this solution is exposed to the light for three or four days, filtered, and then TOO c.c. each of glycerin and methyl alco- hol are added, the solution allowed to stand for several days and finally filtered. An excess of the stain is removed from the sec- tions by subsequent washing either with a 2 per cent, alum solution MICROSCOPIC TECHNIQUE AND REAGENTS. 761 or an acidified alcoholic solution. This solution gives to cellulose, lignin and the protoplasmic cell-contents a violet color. IODINE AND POTASSIUM-IODIDE SOLUTION consists of iodine, 2 Gm. ; potassium iodide, 6 Gm. ; water, 100 c.c. IODINE WATER is prepared by adding as much iodine to dis- tilled water as it will dissolve (about i : 5000). CHLORAL-IODINE SOLUTION consists of a saturated aqueous solution of chloral, to which iodine is added. This reagent is useful for staining the starch grains in the chloroplasts. PHLOROGLUCIN SOLUTION, used as a test for lignin, is a 0.5 to 2 per cent, alcoholic solution of phloroglucin, which is used in conjunction with hydrochloric acid. The reagent should be protected from light. IRON SOLUTIONS are aqueous or alcoholic solutions containing 5 to 20 per cent, of ferric acetate or ferric chloride. These are mostly used as tests for tannin, giving either a bluish-black or greenish-black coloration or precipitate. COPPER-ACETATE SOLUTION is a 7 per cent, aqueous solution of cupric acetate. It is the most distinctive test for tannin, par- ticularly with fresh material, producing a reddish-brown precipi- tate in the cells containing tannin. The fresh material should be cut into small pieces and immediately placed in the solution of copper acetate and allowed to remain for from 24 to 48 hours. The excess of the reagent is then washed out and the material placed in alcohol. SCFULZE'S MACERATING SOLUTION is prepared by adding crystals of potassium chlorate from time to time to warm con- centrated nitric acid. It is employed in the isolation of lignified cells. The material is allowed to remain in the solution for a short time or until there appears to be a disintegration of the tissues. A large excess of water is then added. The material is carefully washed, the cells teased apart and mounted in a solution of methylene blue. SPECIAL REAGENTS comprise all those substances which are employed in the morphological study of the cells, and include solutions of the alkalies (o.i to 6 per cent.) solutions of the mineral acids, which may be weak or concentrated, and solutions of organic acids, as acetic and citric. 762 A TEXT-BOOK OF BOTANY. DOUBLE STAINING, or the use of two stains in the examination of a specimen, furnishes not only a means of beautifying the speci- men, but also has a certain diagnostic value. The following are some of the combinations used: (a) aqueous solutions of car- mine in connection with alcoholic solutions of iodine green; (b) FlG. 419. Crystals of some of the common reagents which not infrequently sepa- rate on the slide and may be mistaken for cell contents: A, isotropic crystals of chloral which occur in cubes about 10 M in diameter or long needles about 50 ^ long; B, phloro- glucin which occurs in broad rectangular plates or ellipsoidal discs from 10 to 35 M- in diam- eter which are doubly refracting with a play of colors; C, cubes of potassium iodide which are isotropic; D, crystals from potassium hydrate solution which separate in broad prisms and branching chains that are doubly refracting and give marked color effects. alcoholic solutions of haematoxylin and saf ranin ; (c) solutions of eosin and methylene blue; (d ) solutions of fuchsin and methylene blue; (e) solutions of gentian violet and Bismarck brown. MOUNTING OF SPECIMENS. — Microscopic preparations or mounts are of two kinds : they may serve a temporary purpose MICROSCOPIC TECHNIQUE AND REAGENTS. 763 •only or they may be prepared so as to serve for future study, the latter being known as PERMANENT MOUNTS. In taking up the study of a specimen it should first be mounted in water and examined ; then the water may be replaced by a weak aqueous solution of glycerin (5 to 10 per cent.) and the specimen examined again. After this preliminary examination other agents and reagents may be employed. Specimens mounted in glycerin will keep for several days and even months. Generally speaking, the only effect which the glycerin has on the tissues or contents is that of swelling them, which is obviated, to a greater or less extent, however, if the glycerin is washed out after an exam- ination is made. In addition to the methods involving the use of glycerin, there are two ways of making permanent mounts, depending upon the employment either of Canada balsam or glycerin jelly as the mounting medium. The method involving the use of the latter is the simpler, and leaves the specimen in such a condition that a re-examination with reagents can be made if desirable. GLYCERIN- JELLY mounts are made as follows : Specimens which have been previously treated are transferred to glycerin and allowed to remain for several hours, the excess of glycerin removed, and the specimen transferred to a warm slide on which a drop of glycerin jelly * has been placed. The preparation is warmed slightly to remove air-bubbles, and a warm cover-glass applied, care being taken to prevent the formation of air-bubbles. Evap- oration of the glycerin jelly is prevented by the use of shellac cements, asphalt varnish or candlewax. The following method may be used for the preparation of CANADA BALSAM MOUNTS : The specimen is cleared, dehydrated by the use of alcohol and then placed in chloroform or benzol. The clearing of the specimen is materially assisted by placing it in oil of cloves or turpentine prior to mounting it. A drop of Canada balsam solution ( i part of balsam to 3 parts of chloroform or 1 KAISER'S GLYCERIN JELLY.— Digest 7 Gm. of gelatin in 42 Gm. of water for two hours on a hot water-bath ; dissolve I Gm. of carbolic acid in 49 Gm. of glycerin ; mix the two solutions ; heat on a water-bath, with occasional stirring, for fifteen minutes, and finally filter through glass wool. The jelly is warmed slightly to liquefy it before using. 764 A TEXT-BOOK OF BOTANY. benzol) is placed on a slide and the specimen mounted. When nearly dry, scrape oft" the excess of balsam, clean the slide and cover-glass with chloroform or benzol, and ring with cement. THE MICRO-POLARISCOPE is a useful accessory in conjunction with the microscope. It is employed in the study of technical products, and is chiefly applicable in the examination of crystals, starch grains and cell- walls. A number of substances, owing to- certain peculiarities of structure, are double-refracting or ANISO- TROPIC, i.e., they polarize light. If the double refraction is strong enough these substances show a play of colors. Of these may be mentioned the raphides and the rosette aggregates of calcium oxalate, cane sugar, citric acid, benzoic acid, caffeine, salicin, aloin, phloroglucin, and the salts of berberine, strychnine, and atropine. The acicular crystals which separate in chloral preparations of gambir also show a play of colors. Among the substances which are anisotropic but give no chromatic effects are starch grains, inulin, mannit, the rhombohedra in catechu and the various types of cell-walls. All substances which form crystals belonging to the isometric system are ISOTROPIC or single-refracting, i.e., do not polarize light, as sodium chloride, the octahedra in gambir, potassium iodide and chloral. When glass, which is an isotropic compound, is heated and suddenly cooled it is changed into an anisotropic body. Micro- scopic glass beads formed by quickly cooling very thin pieces of glass show polarization effects similar to those of wheat starch grains. This has led to the supposition that the polarization effects produced by starch grains are due to tension rather than to a crystalline structure. But this point cannot be definitely settled until it has been determined whether any of the substances composing the layers of the starch grains are capable of crystal- lization. THE SPECTROSCOPE ix MICROSCOPIC ANALYTICAL WORK. — To a limited extent at the present time, and yet very effectively by thos.e who are competent to employ it, the Spectroscope is being employed in the examination of organic coloring substances. This method has the advantage that accurate results can be obtained with small quantities of material. With the proper instruments and with practice one may attain a skill equal to that attained in MICROSCOPIC TECHNIQUE AND REAGENTS. 765 qualitative and quantitative analytical work. The Spectroscope can be used in checking chemical methods and also employed frequently in the detection of mixtures, just as the microscope is used where qualitative chemical methods are not available. The Spectroscope is used not only in the examination of single color- ing principles, but where there are mixtures, and whether these are in solution, on fabrics, on paper, etc. So that for technical chemists, especially for those interested in dyeing and allied indus- tries, it has a very great value. There are several different types of spectroscopes : ( I ) the ordinary, in which the liquid is placed in a long glass cell between the source of light and the slit of the spectroscope; (2) a com- parison spectroscope, where an unknown liquid can be compared with that of a known; (3) the micro-spectroscope, in which a spectroscope is attached to a microscope and the liquid is placed in small tubes. A characteristic spectrum is obtained only when the solution is of the proper dilution. The solutions must be prepared care- fully and interfering substances removed as much as possible. ( Consult : ' Untersuchung und Nachweis organischer Farb- stoffe auf spektroskopischen Wege," by Jaroslav Formanek and Dr. Eugen Grandmougin, Second Edition. " Zur Biologic des Chlorophylls Laubfarbe und Himmelslicht Vergilbung und Etiole- ment," by Ernst Stahl. The Origin and Nature of Color in Plants," Kraemer, in Proc. Am. Phil. Soc., 1904, p. 259.) DARK FIELD ILLUMINATION AND THE ULTRA-MICROSCOPE.- The study of minute particles which are otherwise not visible under the microscope by direct illumination may be accomplished by a simple contrivance known as a reflecting condenser. The principle upon which this operates is similar to when a pencil of sunlight enters a more or less darkened room, causing the par- ticles of dust to become visible. In the same manner the invisible particles in a colloidal solution and the ordinarily structureless substances in an animal or vegetable cell are rendered visible by reason of the contrast between these particles and their dark sur- roundings. The apparatus consists essentially of two parts: (i) a parab- oloid condenser which has two reflecting surfaces so as to bring 766 A TEXT-BOOK OF BOTANY. the rays of light to a focus on the objective and against a dark background; and (2) a funnel stop objective. The latter is an ordinary immersion objective with the addition of a funnel stop back of the lenses so that the diffused rays only enter the eye to the exclusion of the direct rays. An ordinary microscope with a reflecting condenser and a funnel stop objective thus constitutes an ultra-microscope. The illumination is by means of an arc light. If a Welsbach lamp is used it is necessary to employ a bull's-eye lens to concentrate the light upon the mirror. The light is ordinarily reflected through the condenser from the plane mirror of the microscope. Cover-glasses of a standard thickness, 0.17 mm., should be used. The space between the top of the condenser and the microscopic slide containing the object must be filled with a layer of cedar oil in the same way as between the cover-glass and the objective. Time must be taken to perfectly center the condenser with refer- ence to the objective. (Consult: " Dunkelfeldbeleuchtung und Ultramikroskopie,'* by N. Gaidukov.) MICRO-ANALYSIS. The value of the microscope is well established in the examina- tion not only of the living plant but in the study of various techni- cal products. It is usual to give greater prominence to the ANA- TOMICAL or HISTOLOGICAL method of study, based largely upon the form of cells and the structure and composition of their walls. The study of cell contents, as starch grains, calcium oxalate, phyto-globulins, and other definite substances, is being utilized very largely in the examination of technical products and to some extent by students of botany. A number of books have been published dealing with the micro-chemistry or histo-chemistry of some of these substances. For the most part the study of microscopic crystals has been of a very general nature, in that statements are given regarding the general shape of the crystals or their aggregates and their behavior with certain test solutions. The time has come when the study of the crystalline substances found in plants requires, if any real progress is to be made in this direction, that the MICROSCOPIC TECHNIQUE AND REAGENTS. 767 CRYSTALLOGRAPHIC METHOD of examination be utilized. This method originated in the examination of thin sections of rocks and it has been possible by this study to identify the numerous rock-forming mineral species. In those species which are mixed crystals, i.e., made up of isomorphous mixtures of two or more components, it has been possible to determine with some accuracy their composition simply by their optical properties, as for exam- Pic. 420. Codeine: x-shaped skeleton crystals from 10 per cent, alcoholic solution. pie the feldspars. Furthermore, it has been possible to draw conclusions as to the ultimate composition of rocks and the conditions under which they were formed. The value and possibilities of the employment of the crystal- lographjc method in biological studies is well exemplified in the recent work of Reichert and Brown, " The Crystallography of the Hemoglobins." By special means individual crystals of the hemoglobins were obtained and by purely crystallographic methods, including a study of the forms and optical properties of such crystals, the hemoglobins of the 200 species of animals 768 A TEXT-BOOK OF BOTANY. studied were differentiated in a manner that could not have been accomplished by chemical analysis or other methods of procedure. A careful study of much that has been written, and especially of the illustrations that have been made, of micro-crystals in plants and drugs, shows that erroneous conclusions may be easily drawn from the general appearance of crystalline precipitates or aggregates of crystals that are formed. For instance, Yogi has FIG. 421. Cubebin: orthorhombic crystals from Prollius' solution, showing various types of twinning (a, b, c); d, amorphous material in the form of oily drops (under-cooled liquid); e, this amorphous material crystallizing in aggregates. shown that the sphero-crystals, found in the glandular hairs of M cut ha piperita and considered by some to be menthol, are found in leaves of many of the Labiatse. Again, very many sub- stances produce aggregate groups which closely resemble each other, as of citric acid, cocaine hydrochloride, etc. In regard to the value of the crystallographic method we quote the following paragraph from Brown (loc. cit.} : " When a chemical compound solidifies from fusion, solution or vapor under conditions which are favorable to the development of MICROSCOPIC TECHNIQUE AND REAGENTS. 769 individuals, its particles tend to arrange themselves in regular order, so that a definite structure is produced. The external form of the individuals is also regular, being bounded by planes in definite relation to each other so that polyhedral solids are produced which are called CRYSTALS. The regular arrangement of the atoms among themselves, and of the molecules which FIG. 422. Strychnine sulphate: tetragonal crystals in polarized light, showing side aspect. they build up, is so characteristic of substances of definite com- position that the crystalline condition of dead matter is the normal condition. Differences in chemical constitution are accompanied by differences of physical structure, and the crystallographic test of differences of chemical constitution is recognized as the most delicate test of such differences." 49 A TEXT-BOOK OF BOTANY. It is apparent that, apart from their solubility, color reactions, behavior towards reagents, etc., the substances with which we are dealing should be prepared in such a manner that isolated crystals are formed and not aggregates or groups. These isolated crystals can then be studied independently. The reason why FIG. 423. Hydrastine: large, nearly equidimensional orthorhombic crystals from alcoholic solution. aggregates are formed is because the crystals are permitted to grow too rapidly on the slide. This is usually the case in the usual method of procedure in securing crystals, i.e., by adding a drop of a solution to the slide, and then allowing it to evaporate spontaneously, under ordinary conditions. If, on the other hand, the rate of evaporation is lessened so that there is a slowing down of the growth of the crystals, individuals may be obtained of MICROSCOPIC TECHNIQUE AND REAGENTS. 771 almost any size desired. And it will be found that these isolated crystals may be quite as easily prepared as the aggregates which seem so characteristic to- the average student. Special methods, however, may be necessary to obtain such isolated crystals. For instance, single crystals of menthol (Fig. 126) are obtained by FIG. 424- Piperine: monoclinic crystals, mostly on the clinopinacoid, showing the oblique terminations, obtained from hot alcoholic solution. means of sublimation rather than from solutions. Cumarin crystals are easily obtained by controlling the temperature of the melted mass, etc. The interest in these crystalline substances is becoming greater as foods and drugs and technical products are subject to stand- ards of purity. Most of the crystalline constituents common to 772 A TEXT-BOOK OF BOTANY. plant products are usually said to be calcium oxalate. This sub- stance is insoluble in water, alcohol, and acetic acid, soluble in the mineral acids and occurs usually in definite crystals. These crystals are rather easily studied in Iris, Quillaja, etc. (see page 186). They are found to crystallize either in the tetragonal or monoclinic systems, sphenoids of the latter being present in Belladonna (see pages 183-192). Some substances occur in a crystalline form even upon the commercial product, as vanillin upon vanilla pods and cumarin upon tonka seeds ; or crystals may be found in special cells, as piperine (Fig. 424) in Piper album and Piper nigrum. In alco- holic material, particularly of the Composite, characteristic sphero- crystals are found, as in inula (see pages 150-154). Sometimes similar sphero-crystals are observed upon soaking the drug of commerce in water and then adding alcohol, as in Scilla. Again, crystalline substances separate upon the addition of mineral acids, as when nitric acid or sulphuric acid is added to sections of Hydrastis (Fig. 95). Again, upon dissolving the product either in water, as with catechu, or in solutions of chloral, as with gambir, a crystalline residue remains. Finally, upon extracting the dried plant with suitable solvents, as Prollius' solution, and evaporating the solvent, characteristic crystals separate, as with coca, hydrastis, nux-vomica, cinchona, cola, guarana, etc. ; or distinct crystalline precipitates may be obtained upon the addition of special reagents, as palladous chloride to solutions containing cocaine hydrochloride (Fig. 97), or gold chloride to solutions containing caffeine (Fig. 96). Attention has already been directed to the fact (pages 173-176) that quite a number of plant principles are capable of being sublimed. For some time past, in the study of certain of the cryptogams, as bacteria, yeasts, and fungi, there has been a disposition to rely upon physiological rather than morphological characters, this being due not only to the fact that these are more constant and characteristic in these organisms, but also to> the fact that distinct morphological characters are entirely wanting in some cases. While the necessity for this additional study in the higher plants is not so apparent on account of the presence of well-defined morphological characters, still the value of physiological marks MICROSCOPIC TECHNIQUE AND REAGENTS. 773 as one of the bases of classification is coming to be recognized. The best illustration of this is to be found in the monograph of the genus Eucalyptus by Baker and Smith, in which they have utilized the chemical properties and physical characters of the oils, coloring principles, tannins, etc., in establishing differ- ences of affinities or species. There is a growing tendency on the part of investigators to study micro-chemically some of the char- acteristic plant constituents, as alkaloids, etc. As a rule, how- ever, the descriptions are superficial and the identification is by means of color reactions. No real scientific progress will be made until the botanist employs the petrographical microscope and is fairly well grounded in the principles of physical and chemical crystallography. The work is by no means so simple as in ordinary microscopic work, but when the principles governing the optical study of crystals are mastered, the study will appeal to botanists not only as a fertile field for research but also as a subject of importance in both morphological and taxonomic work. The study of microscopic crystals is accomplished by means O'f the petrographical microscope. Brown (loc. cit.) has stated succinctly the nature and use of this instrument : " The necessity of studying small crystals, . . . has re- sulted in the evolution of a form of microscope which is at once a goniometer, a polariscope, and an instrument for measuring optic axial angles — in short, for determining the physical crys- tallographic constants of small crystals. . . . The polari- scope portion of the petrographical microscope enables the ob- server to determine the position and relative value of the elasticity axes of crystals, to observe the position of the optic axes, and to determine their inclination to each other and to the elasticity axes. From these data the optical character of the crystal is determined. These OPTICAL REACTIONS may be studied by this instrument with as much ease, and in general with as much accuracy, as with the larger and better graduated polariscope; and the data thus obtained are quite as accurate in most cases as those obtained by the use of the larger instruments. The use of the special eye-pieces arranged with artificial twins of calcite or quartz enables the observer to determine the extinction 774 A TEXT-BOOK OF BOTANY. angles of the crystals with as much accuracy as can be done with any form of polariscope. ' From such observations made with the aid of this form of microscope the following constants may be determined : ( i ) The plane angles of the crystals, in most cases the interfacial angles, giving the data from which the axial ratios are computed — in other words, the morphological constants of single crystals. ' (2) The relation of the composite crystals or twins to each other, their angles, and the position of the twin plane, twin axis, composition plane, and other constants of the twin crystals. ( (3) The pleochroism of the crystals, the character of the colors of the light vibrating parallel to the elasticity axes in the crystals. This is effected by the use of the single polarizing prism below the stage. By analyzing this light with the micro- spectroscope the differences of tint and color may be given quantitative values in wave lengths. ( (4) The position and relative values of the light elasticity axes in the crystals, upon which depend the angles of extinction of the crystals, measured from certain crystallographic axes or planes or edges. In uniaxial crystals (tetragonal and hexagonal systems) there are two such elasticity axes — the ordinary ray des- ignated as 712 Lady's mantle, 435 slipper, 443 thumb, 455 Laetia, 623 Laevulose, 155 Lafaensia, 628 Lagerstroemia, 629 Lagctta, 628 Lamellae, 259 middle, 254 secondary, 255 Lamina, 348. 385 Laminaria, 30 Lamium, 449 Lanate. 354 Lanceolatus-a-um, 449 Landolphia, 241 Langsdorffia, 519 Langsdorffii, 449, 571 Laplaceae, 618 Laportea, 449, 517 Lappa, 449 Larch, tannin in, 206 Larix, 1 18 Larkspur, 443, 535, 574 Lateral branches, 312 root, 301, 312 Laterifolius-a-um. 449 Laticiferous vessels, 240 Latex, 238. 546 Lathyrus, 450, 576 Lauraceas, 450, 544 Laurel, 450, 544 bay, 461 great, 647 ground, 444 mountain, 648 noble, 544 nut, 212 oil, 619 sheep, 449, 648 spurge, 627 Laurus, 544 Lavandula, 450 hairs in, 282, 284 Lavender, 450, 676 pollen of, 404 sea, 450 spike, 676 true. 676 Lawsonia, 450, 629 Layer, resinogenous, 226 Leaf, apex of, 354 792 INDEX. Leaf, base of, 356 bifacial, 366 climber, 324 dorsiventral, 366 functions of, 350 inner structure of, 365 margin of, 356 mold, formation of, 249 netted-veined, 353 outer morphology of leaf, 348 palmi-nerved, 353 parallel-veined, 352 reticulate, 353 simple, 348 teeth, glandular, 283 unifacial, 366 venation, 352 Leaflets, 356 Leather, dye, 633 wood, 444, 627 Leaves, 299, 348 anatomical differences in, 370 autumn, 178 bifacial, 349 compound, 356 cylindric, 349 decay of, 250 divergence of, 363 dorsiventral, 349 equitant, 349 foliage, 1 20 forms of, 354 modified, 364 movement of, 357 scale, 1 20 sporangial, 120 surface of, 353 sword-shaped, 349 texture of, 354 Lecanora, 74 Lecidea, 75 Lecithin, 214 Lecythidaceas, 629 Lecythis, 629 Ledum, 450 Leek, 485 Legume, 419 Legumelin, 195 Legumin, 195, 576 Leguminosae, 450, 567, 575 Lemna, 300 Lemnaceae, 450, 478 Lemon, 450, 584 oil, 584 protein in, 199 Lens, 450, 576 Lenticels, 291, 292 Lenticus, 450 Lentil, 450, 576 protein in, 199 starch in, 148 sugar in, 157 Lentus-a-um, 450 Lenzites, 62 Leontin, 538 Leonurus, 450, 682 Lepargyraea, 628 Lepidium, 450, 544 Lepidodendron, 100 Leptandra, 450 Leptilon, 713 Leptome, 276, 312 Leptospermum, 632 Lettuce, 449 poison, 712 Leucadendron, 450, 517 Leucaena, 575 Leuco-compounds, 179 Leucoplastids, 136, 137 Leucosin, 195 Leucospermum, 518 Leucothce, 648 Levisticum, 450, 643 Levo-glucose, 155 Levulose, 155, 563 Lianas, 324 Liane, 324, 602 Libriform, 270 Lichens, 71 color in, 179 economic uses of, 73 on Rhamnus Purshianus, 292 roots of, 73 Licorice, 568 fern, 96 section of, 271 Spanish, 568 wild, 704 Life-processes, 134 Light relation of leaves, 349 shoot, 329 Lignin, 256, 580 Lignocellulose, 256 Lignone, 256 Ligulate flower, 711 Ligule, 356 Liguliflorae, 711 Ligusticum, 450 Ligustrum, 450, 661 Lilac, 460 garden, 66 1 Liliaceae, 450, 485 Liliales, 485 Liliiflorae, 485 Lilium, 485 Lily, 450, 485 lotus, 453 of the valley, 442, 485, 487 spider, 448 yellow pond, 453 Lima beans, protein in. 199 Limb, 386 Lime fruit, 584 tree, 608 Limnophila, 358 Limonene, 583 Limonium, 450 Limonum, 450, 584 Linaceae, 450, 579 Linalool, 233, 564, 583 Linalyl acetate, 234 Linamarin, 169 Linaria, 691 Linariin, 691 Linden, 461, 608, 609 hesperidin in, 153 Lindera, 544 Linen, 580 Linodendron, 628 Linseed, oil in, 213 Linum, 579 structure of, 428 Lion's foot, 723 Lippia, 450, 673 Lippiol, 673 Liquidambar, 450, 558 Liquorice (see Licorice) Liriodendrin, 540 Liriodendron, 450, 539 Lithospermum, 450 Litmus, 74 Litsea, 546 Liverworts, 76, 80, 82, 83 Lobed, 356 Lobelia, 384, 450, 710 blue, 710 red, 710 section of leaf, 370 seed-coat, 429 Lobeliaceae, 450 Loco, 574, 575 Loculicidal, 412 Locust, 457, 567, 576 Loeffler's methylene blue, 757 Logania, 450, 66r Loganiaceae, 450, 661 Logwood, 571 Lomatia, 518 Lonchocarpus, 575 Lonicera, 450, 707 Loosestrife, 451, 628 purple, 628 Lophophora, 625 Lophophorine, 625 Loranthaceae, 450, 518 Loranthus, 518 Lotus, 450, 532 Lovage, 450, 643 Lucerne, 577 Luffa, 710 Luffa-sponge, 710 Lumen, false, 269 Lunaria, 450, 553, 554 Lungwort, 456 Lupeol acetate, 659 Lupine, 451, 574 seeds, lecithin in, 214 Lupinidine, 575 Lupinin, 575 Lupinine, 575 Lupinus, 451, 575 INDEX. 793 Lupinus luteus, protein in, 199 root tubercles on, 307 Lupulin, 515 Lupulus, 451 Lusitanicus-a-um, 451 Luteus-a-um, 451 Luzula, 493 Lychnis, 451, 53 1 Lycoperdaceae, 59 Lycopodiaceae, 97, 451 Lycopodium, 99, 213 Lycopus, 451 Lyngbya, 10 Lysigenous, 226 Lysimachia, hairs in, 282 Lythraceae, 628 Lythrum, 400, 451, 628 Mabea, 592 Macaranga, 593 Macassar, 519 Mace, 212, 451, 543 protein in, 200 starch in, 148 Macis (see Mace) Maclura, 451, 516 Maclurin, 180 Macrocystis, 30 Maculatus-a-um, 451 Madder, 697, 702, 703 Mad-dog skullcap, 675 Magnolia, 451, 539, 540 Magnoliaceae, 539 Magnolin, 540 Magonia, 604 Mahogany family, 588 tree, 589 Mahonia, trailing, 537 Mahurea, 619 Maidenhair, 434, 439 Maize, 462 Majalis, 451 Majorana, 451 Major-us, 451 Malabanthri folia, 568 Malambo bark, 592 Male generative-cell, 298 Mallotus, 451, 591 hairs of, 285 Mallow, 609, 6 1 1 glade, 453 Indian, 610 rose, 448 Malpighia glabra, tannin in, 206 Malpighiaceae, 589 Maltase, 242 Maltose, 155 Malva, 611 Malvaceae, 451, 609 Malvales, 607 Mamillosus-a-um, 451 Mammea, 620 Mammei apple, 620 Mammey wine, 620 Mandarin, 584 Mandrake. 455 Mangifera, 599 Mango, 620 Mangos, 599 Mangosteen, 446, 619 Mangostin, 619 Mangrove, American, 630 forest, 304 swamps, 631 Mangrovin, 588 Manihot, 594 Manna, 155. 45L 565, 661 Briancon, 118 of Israelites, 74 Persian, 155 Mannit, 563 Mannitol, 155 Mannose, 169 Manometer, 306 Maple, 434, 602 sugar, 157 syrup, 602 Maracaibo balsam, 572 Maranta, 496 arrow root, 496 Marantaceas, 496 Marasmius, 58 Marcescent, 388 Marcgravia, 617 Marcgraviaceae, 616 Marchantia, 81 Marginal, 451 Marginalis-e, 451 Marginicidal, 411 Margin of leaf, 356 Mariana, 451 Marigold, 387, 7i8 bur, 438 marsh, 439 Marilandicus-a-um, 452 Maritimus-a-um, 451 Marjoram, 451 sweet, 679 wild, 454. 679 Marking tree, East Indian, 597 Marmelos, 451 Marrubium, 451, 676 Marsdenia, 66? Marsh elder, 448 Marshmallow, 435, 609 Marsilea, 451 Marsilia, 94, 95 Marsupium, 451 Marvel-of-Peru, 528 Massoy bark oil, 546 Mastic, 452, 599 tree, 450 Mastigocoleus, 8 Mate, 600 germination of, 730 Matico, 452, 504 section of leaf, 371 Matisia, 612 Matricaria, 452, 715 Mawseed, 547 May apple, 538 Mayflower, 649 Maysin, 195 Maytenus, 602 May weed, 442 Meadow beauty, 634 sweet, 459 Meal, mountain, 39 Measurement, microscopic, 754 Medeola, 485 Medicago, 577 ferment in, 244 Medicinal plants, cultivation of, 727 Medicus-a-um, 452 Medinilla, 634 Medlar, Japanese, 562 Medullary rays, 314 Megasporangium, 108, 298, 375 Megaspore, 86, 298 germination of, 298 Megasporophylls, 108, 375 Melaleuca, 452, 632 Melastoma, 634 Melastomataceae, 633 Melia, 588 Meliaceas, 588 Melibiose, 155 Melilotus, 452 Melissa, 452, 679 Melon, 441, 454 cucumber, 443 musk, protein in, 199 tree, 624 Membrane, primary, 255 Memecylon, 634 Mendel's Law, 132 Menispermum, 539 Menispermacea?, 538 Menispermum, fibrovascular bundle of, 337 woody vine of, 322 Menispine, 539 Mentha, 452, 678, 384 species of, 676 Menthol, 233 Menyanthes, 452, 664, 665 Menyanthin, 664 Mercurialis, 452, 593 Mercuric chloride, as fixing agent, 756 Mericarp, 417 Meristems, 253, 254, 291 Mermaid's hair, 10 Mescal, 492 buttons, 625 Mescaline, 625 Mesembryanthemum, 529 Mesocarp, 410 Mesophyll, 366 794 INDEX. Mestome, 272 sheaths, 367 strand, 313, 341, 342, 343 Mesua, 619 Metabolism, 252 Metachlamydeae, 504, 643 Methyl salicylate, 234 Methylene blue, as staining agent, 757 Methysticin, 177, 508 Methysticum, 452, 508 Metroxylon, 475 Meum, 452 Mexican linaloe oil, 588 Mezereum, 443, 452, 627 Michelia, 540 Microcarpus-a-um, 452 Micrococci, 14 Micrometer, 754 Micrometry, 754 Micron, 754 Micro-polariscope, 764 Micropyle, 425 Microscope, ultra, 765 Microscopic measurement, 754 Microsomata, 136 Microsomes, 136 Microspermae, 496 Microsporangia, 120, 298 Microspore, 298, 375 germination of, 298 Microsporophylls, 105, 375 Microtome, 749 Midrib, 353 Mignonette, 120, 457, 554 Mikania, 452 Milaceus-a-um, 452 Mildews, 44 Milfoil, 434 Milk, clotting of, 244 juice, 238 ropy, 244 vetch, 437 Milkweed, 437 family, 668 Milkwort, 455 family, 589 white, 589 Millefolium, 452 Millet, starch in, 148 Millettia, 575 Millimeter, 754 Mimosoideae, 567 Mimusops, 659 Mineral cellulose walls, 258 Mint, 449, 452 cat, 453, 680 family, 673 horse, 452 Mio Mio, 723 Miocene, 117 Mirabilis, 528 Mistletoe, 450 American, 531 Mistletoe, European, 518 family, 518 oak, 518 Mitchella, 452, 697, 704 Mitella, 452, 556 Mitrewort, 452, 556 false, 556 Moccasin flower, 498 Mock orange, 556 Modified leaves, 364 roots, 306 Mold, black, 45 water, 42 Mollis-e, 452 Monandrous, 381 Monarda, 452, 679 oil, 680 Monkey-bread tree, 612 Monkey-pot tree, 629 Monkshood, 434 Monniera, 452 Monocarpia, 542 Monoclinic crystals, 183, 184 Monocotyledons, 120, 463 Monoecious, 392 Monosaccharose, 154 Monotropa, 452, 644 Montanus-a-um, 452 Moonseed, Canada, 322, 539 family, 538 Moonwort, 438, 450 Moraceae, 513 Morchella, 58 Morel, 58 Morinda, 704 Morindin, 170, 704 Moringa, 223, 554 pterygosperma, 212 Moringaceae, 554 Morning glory, 448, 668 Morphine, 547 Morphology, I Morus, 452, 517 Moss, bird's nest, 103 club, 97. 451 groups, 84 Iceland, 73, 440 Irish, 31 reindeer, 74 scale, 83 sea, 441, 446 Mother-clove, 631 Motherwort, 450, 682 Mould (see Mold) Mountain ash, 459 elder, 706 laurel, 648 Mounting of specimens, 762 Mounts, permanent, 763 Mourera, 556 Movements of leaves, 357 Moxa, 725 Mucedo, 45 Mucilage, 218, 565 chemical classification, 222 Mucilage, forms of, 221 in sassafras, 263 walls, 257 Mucor, 45 Mucuna, 452, 576 Mugwort, common, 719 Mulberiy, 452 black, 517 family, 513 fruit, 409 white, 517 Mullein, 691 hairs of, 286 Mundulea, 575 Muntingia, 609 Muricatus-a-um, 453 Musa, 496 Musaceae, 496 Musci, 84 Mushrooms, 434 common, 59 edible, 58 lecithin in, 214 poisonous, 58 propagation, 56 Muskmallow, 434 Musk-melon, 710 protein in, 199 Musk seed, 611 substitute, 611 Mustard, 438, 459 ball, 453 black, 552, 553 family, 551 fruit, 409 garlic, 553 hedge, 459, 553 protein in, 199, 200 treacle, 445, 553 white, 552, 553 wild, 553 yellow, germination of, 299 Mutation, 132, 247 Mycelium, 41 Mycose, 155 Myelin, forms, 215 Myosotis, 453, 670 Myrcene, 632 Myrceugenia, 632 Myrcia, oil, 632 Myrica, 211, 453, 508, 509 cerifera, 212 Nagi, tannin in, 206 species, 508, 509 Myricaceae, 508, 509 Myricales, 508, 509 Myricaria, 621 Myricin, 594 Myristica, 453, 543 Myristicaceae, 543 Myristin, 691 Myrobalans, 633 beleric, 633 chebula, 633 INDEX. 795 Myrobalans, long, 633 tannin in, 206 Myrosin, 243 Myroxylon, 623 Myrrh, 442, 453, 586. 587 Myrtaceas, 631 Myrtales, 627 Myrtifloras, 627 Myrtle family, 631 tree, 453 wax, 212, 453 Myrtus, 453, 632 Nabalus, 723 Naiadaceas, 466 Naiadales, 466 Naked flowers, 393 Napaca, 453 Napasa, 612 Napellus, 453 Naphthalene, derivatives, 179 Naphthol black B.. 183 Narcissus, 453. 492 Nardus, 453 Naringin, 169, 170, 585 Nasturtium family, 579 Natural selection, 131 Navel orange, 584 Navicola, 37 Nectandra, 453, 546 Nectar, 402 apparatus, 408 poisonous, 402 Nelumbo, 453, 532 Nepenthaceae, 555 Nepenthes, 555 Nepeta, 453, 680, 681 Nephelium, 603 Nerium, 668 Neroli, 583 Nerved leaf, 352 Nerves, 352 Nesaea, 628 Neslia, 453, 554 Nessin, 628 Netted-veined leaf, 353 Nettle, 461, 517 dead, 449 horse, 684 small, 517 stinging, 287, 5*7 wood, 449 Nicotiana, 453, 688 Nicotianin, 688 Nicotine, 688 Nigella, 453 Niger-gra-grum, 453 Nigger-toe, 630 Night-blooming cereus, 625 Nightshade, 459 deadly, 684 enchanter's, 441, 634 Nitrogen bacteria, 307 Nobilis-e, 453 Node, 320 Nomenclature, 2 Botanical, 430 Nopalea, 627 North American papaw, 542 Nostoc, ii Nucellus, 108, 124, 298 Nucleo-proteins, 194 Nucleoles, 136 Nucleus, 2, 136 function of, 140 of starch grain, 144 Nuphar, 531 Nupharine, 531 Nut, 420 Nutation, 358 Nutgall, 334, 446 Nutlet, 420 Nutmeg, 212, 453, 542, 543 protein in, 200 starch in, 148 Nux-vomica, 453, 66 1 endosperm of, 265, 428 hairs of, 286 Nyctaginaceae, 528 Nyctinastic, 361 Nyctitropic, 361 Nymphaea, 453 Nymphaeaceae, 531 Nyssa, 453 Nysso, 518 Oak, 457, 5H acorns, 148 sugar in, 157 bark of, 295 black, 512 mistletoe, 518 poison, 595 western, 597 red, 512 tannin in, 206 tannin in, 206 white, 511, 512 tannin in, 206 Oats, 437 protein in, 199 starch in, 148 structure of, 423 sugar in, 157 Obcordate, 355 Obtuse, 355 Obtusifolius-a-um, 453 Occidentalis-e, 453 Ochrocarpus, 619, 620 Ochroma, 612 Ocimum, 679 Ocotea, 546 Ocotilla, 621 wax, 621 Ocrea, 520 Octomeles, 625 Ocular micrometer, 754 Odontorhizon, 453 Odoratus-a-um, 453 CEdogonium, 25 CEnanthe, 643 (Enothera, 453, 634, 635 Officinalis-e, 453 Oil, ajowan, 609 apeiba, 643 apopin, 234 bay, 632 ben, 212 benne, 691 bergamot, 584 bigardia, 584 cajeput, 632 candle nut, 213 carapa, 589 cedar, as clearing agent, 757 cedar-wood, 589 chaulmoogra, 214, 623 cineol containing, 544 clove, as clearing agent, 757 coccos, 623 cocoa-nut, 212 Coniferae, 119 cotton see'd, 611 Croton, Mexican, 591 cumin, 643 curcas, 591 dill, 643 essential, as clearing agent, 757 Eucalyptus, 631 fatty, 546 Fiji, 519 fixed, 210 as a reserve, 217 function of, 235 globule, detection of, 752 kapac, 611 laurel-nut, 619 lemon, 584 marjoram, as clearing agent, 757 massoy bark, 546 Mexican linaloe, 588 Monarda, 680 myrcia, 632 Neroli, 583 non-drying, 691 olive, 213, 660 orange peel, 583 palm, 211, 474 palm-nut, 212 pepper, Japanese, 585 rose, 564 sandal, 518 santal, Australian, 519 sesame. 691 spike, 679 sweet anise, 643 tunga, 213 turpentine, as clearing agent, 757 volatile. 225 796 INDEX. Oil, volatile, botanical clas- sification, 232 characteristics of, 231 composition, 233 culture of plants yield ing, 747 formation, 235 micro-chemistry of, 231 water fennel, 643 Okra, 6 1 1 Olea, 660 Oleaceae, 453, 660 Oleander, 668 cork in, 293 Oleandrin, 668 Oleo-resin, 225 Oleum, 453 Cedralae, 589 Lavandula, 676 Rosmarinus, 676 Theobromatis, 612 Oleuropein, 661 Olibanum, 587 American, 587 Olive, 453, 660 family, 660 oil, 660 tree, 660 Onagraceae, 634 Onion, 435, 485 sea, 461 sets, 327 starch in, 148 sugar in, 157 Onoclea, 92, 453 Ononidis, 576 Ononis, 576 Ontogeny, 130 Oogonium, 5 Oomycetes, 42 Oosphere, 5 Oospore, 5 Opegrapha, 75 Operculina, 453 Operculum, 79 Opium, 241, 453 collection of, 549 poppy, 546, 547 Optical reactions, 773 Opulus, 454 Opuntia, 454, 626, 627 Opuntiales, 625 Orange, 437, 44L 582 bitter, 583 blood, 584 Curacao, 583 G. G., 182 kidney-glove, 584 kumquat, 584 Malta, 583 mock, 455, 556 navel, 584 osage, 451, 516 otaheite, 584 Portugal, 583 Orange, protein in, 199 root, 448 Seville, 583 sugar in, 156 sweet, 583 Orcein, 74 Orchid, 496 Orchidaceae, 496 Orchidales, 496 Orchil, 75 Orchis, fringed, 447 round-leaved, 499 white fringed, 500 Orcin, color in, 179 Ordinary ray, 774 Orellin, 622 Organography, I Organs, nutritive, 3 plant, 3 sexual, 3 vegetative, 3 Orientalis-e, 454 Origanum, 454, 679 Cretian, 679 oil, 679 Orlean, 621 Ornithogalum, 485 Ornus, 454 Orobanchaceae, 696 Orpine family, 556 Orris root, 332, 492 starch, 143 Orthotoschies, 363 Oryza, 467 Oscillaria, 10 Oscillatoria, 10 Osmosis, 251 Osmunda, 365, 454 Ostrya, 454, 510 Otaheite orange, 584 Ovary, 120, 376 tissues of, 406 Ovules, 376, 378 development of, 124 forms of, 379 positions of, 379 Oxalidaceae, 579 Oxalis, 454, 579 Oxidation, 252 Oxyacanthine, 539 Oxycedrus, 454 Oxycoccin, 656 Oxycoccos, 656 Oxydases, 245 Oxygen, 252 in fucus, 28 Oxymethylanthraquinone, 176 Pachira, 611 Pseonia, 454 Palaquim, 658 Pale, 466 Palisade tissue, 366 Palmae, 473 Palmavely-compound, 356 Palmately-veined leaves, 353 Palmatus-a-um, 454 Palmetto, 458 saw, 459 Palmi-nerved leaf, 353 Palm oil, 474 Palms, 473 Palustris-e, 454 Panax, 305, 454, 636, 638 Pandanales, 463 Pangium,i98, 623 Panicles, 396 Paniculatus-a-um, 454 Panicum, 454 Pansy, 622 Papain, 244, 542, 624 Papaver, 454, 546, 547 Papaveraceae, 546 Papaverales, 546 Papaw family, 624 ferment in, 244 North American, 437, 542 tree, 624 Papayotin, 624 Paper, Chinese rice, 636 Papilionaceous, 386 Papilionatae, 567 Papillae, 451 Pappus, 711 Paprika, protein in, 200 Papyrifer-a-um, 454 Paracatechin, 607 Para cress, 724 Paradise grains, 494 Parallel-veined leaf, 352 Para-nut, 629, 630 Parasites, 40 Pareira, 539 Parenchyma, forms of, 262 rays, secondary, 314 sheaths, 367 Paricine, 546 Parietales, 615 Pari-pinnate, 357 Parnasia, 209, 556 Paronchia, 531 Parrya, 553 Parsley, 455 garden, 643 Parsnips, protein in, 199 Partridge berry, 697 Parviflorus-a-um, 454 Pasque flower, 456 Passiflora, 454, 623 Passifloraceae, 623 Passion flower, 454, 615. Patchouli oil, 679 Patchouly, 679 Pauciflorus-a-um, 454 Paullinia, 454, 603 Paviin, 602 Payena, 659 Pea, 198, 576 everlasting, 450 INDEX. 797 Pea, garden, 576 germination of, 299 lecithin in, 214 protein in, 199 starch in, 148 sweet, 576 Peach, 435, 562 oil in, 213 protein in, 199 sugar in, 156 Peanut, 199, 576 oil in, 213 plant, 401 Pear, 457, 562 prickly, 454, 526, 627 protein in, 199 Peat, bog, 250 upland, 250 Pectase, 243 Pectin, 243, 563 origin of, 255 Pectinase, 243 Pectose, 243, 563 Pedaliaceae, 691 Pedatus-a-um, 454 Pedicel, 393 Peganum, 581 Pelargonium, 579 Pellitory, 435, 457, 7U Pellotine, 625 Pelosine, 546 Peltatus-a-um, 454 Pencils, 117 Penicillium, 49 Pennatifolius-a-um, 454 Penny cress, field, 553 Pennyroyal, 447 American, 676 Pentalostigma, 593 Pentapetes, 615 Pentastichous, 363 Penthorum, 454, 556 Pentose, 154 Peony, 454 Pepo, 420, 454, 708 Pepper, 455 African, 687 black, 504, 505 cayenne, 200, 687 grass, 553 long, 504 moor, 585 picking, 507 protein in, 200 red, 439, 688 starch in, 148 water, 448 white, 504 Pepperidge, 453 Peppermint, 676, 678 camphor, 233 culture, 746 Peramium, 503 Pereirae, 454 Perennial herb, 330 Perezia, 723 Perfect flower, 392 Perfoliate, 356, 454 Perfoliatus-a-um, 454 Perforatus-a-um, 455 Perianth, 382 Periblem, 253 Pericambium, 312 Pericarp, 410 Pericycle, 312 Periderm, 291 Perigynous, 389 Perisperm, 425 structure of, 429 Peristome, 79 Periwinkle, 668 Permanent mounts, making of, 763 Peronospora, 43 Persea, 455 Persian tobacco, 688 Persicaria, 455 Persimmon, 444, 660 fruit, 659 Japanese, 660 Persistent, 388 Personate, 388 Persoonia, 518 Pertusaria, 73 Petals, 120, 374, 382 Petiole, 348 Petroselinum, 455, 643 Peziza, 46 Phaca, 575 Phaeophyceae, 17, 28 Phaius, 137 Phallaceae, 59 Phanerogams, 5 Phaselin, 195 Phaseoleae, hairs in, 282 Phaseolin, 195 Phaseolus, 455, 576 apical region, 321 Phasins, 198 Pheasant's eye, 434 Phellandrene, 632, 643 Phellogen, 290, 291, 313 Phenol, derivatives, 179 Phenolases, 245 Phenols, 234 Phenyl ethyl alcohol, 564 Philadelphia fleabane, 713 Philadelphus, 455, 556 Phillipinensis-e, 455 Phlobaphene, 203 Phloem, 312 Phloridzin, 169, 565 Phloroglucin, crystals, 762 reaction, 256 solution, 761 Phlox, 455, 670 tracheae of, 274 Phoenix, 475 endosperm in, 265 Phoradendron, 518 Phospholipines, 217 Photosynthesis, 137, 299, 350 fixed oils in, 210 Phycocyanin, 8 Phycomycetes, 42 Phyllanthus, 593. 594 Phyllotaxis, 363 Phylogeny, 129 Physica, 73 Physical basis of life, 138 Physiological experiments, 350 Physiology, I Physostigma, 455, 572 Phytelephas, 473 endosperm in, 265 Phyto-bezoars, 626 Phyto-cecidien, 334 Phyto-globulins, 193, 197 Phytolacca, 455 leaf, section of, 369 root, section of, 318 Phytolaccaceae, 528 Phytomelane, 258 Phytosterol, 214 Phytovitellins, 193 Pianeze III b, 70 Picea, 109, 119, 455 Pichi, 684 Pickerel weed, 482 Picramnia, hairs in, 282 Picrasma, 455, 585 Picric acid, 756 Picric-sulphuric acid, as fix- ing agent, 756 Picro-crocin, 493 Picrotoxin, 455, 539 Piereskia, 627 Pieris, 648 hairs in, 282 Pigments, 138 resins, 238 respiration, 181 Pignone, 117 Pignut hickory trees, 333 Pigweed, 441 Pileus, 57 Pilocarpus, 455, 582 Pimelea, 627 Pimenta. 455, 632 starch in, 148 Pimpernel, 436, 455 Pimpinella, 455, 639 Pinaceae, groups of, 113 Pinanga, 621 Pine, 455 Cuban, 113 frankincense, 112 great sugar, 112 loblolly, 112 long-leaved, 113 nut, 117 oil in, 213 pitch, 112 INDEX. Pine, prince's, 644 seeds, 117 spruce, 112 sugar, 117 swamp, 113 torch, 112 Weymouth, 106 white, 106 yellow, 113 Pineapple, 436, 480 ferment in, 244 Piney resin, 621 Pinguicula, ferment in, 244 Pink, 443, 531 Carolina, 66 1 cultivated, 531 lady's slipper, 498 root, 459 Pinkster flower, 646 Pinnately-compound, 356 Pinus, 455 Strobus, 106 sylvestris, 213 tannin in, 206 Piper, 426, 455, 504. 506 (see also Pepper) methysticum, 177 species of, 504 Piperaceae, 504 Piperales, 504 Piperine, 161 crystals, 771 Piperitus-a-um, 455 Pipitzahoic acid, 723 Pipsissewa, 455, 644 Pircunia, 528 Pirolaceae, 644 Piscidia, 575 Piscipula, 455 Pistachio, 455- 599 Pistacia, 208, 455, 597 Pistil, 120, 376 compound, 376 different types of, 377 simple, 376 Pistillate, 392 Pisum, 576 ferment in, 244 germination of, 299 Pitch, Burgundy, 119 Canada, 119 Pitcher-plant, 361, 458, 555 family, 554 Pith, sassafras, 263 Pithecolobium, 575 Pityrodia, hairs in, 282 Placenta, 377 structure of, 408 Plaited, 389 Planchonia, 629 Plane tree family, 559 Planifolius-a-um, 455 Plant hairs, 353 henna, 450 Plantaginaceae, 696 Plantago, 455, 694, 696 ferment in, 244 Plantain, 455, 694 common, 694 family, 696 flowers, 400 Plastids, 2, 138 Platanaceae, 559 Platanus, 559 Plates, sieve, 276 Platinic chloride, 165 Platonia, 620 Pleistocene clays, 117 Plerome, 253 Pleurisy-root, 667, 668 Pleurococcus, 20 Pleurosigma, 36 Plicate, 364, 389 Plum, 456 French, 562 grape, 606 oil in, 213 protein in, 200 sugar in, 156 Plumule, 127, 426 Pod, 420 Podophyllum, 455, 538 rhizome of, 324 Podostemaceae, 556 Podostemon, 455, 556, 679 Point of origin of growth, 144, 300 of vegetation, 300 Poison, arrow, 575, 593, 597, 633, 662 curare, 539 fish, 539, 575, 604, 606 ivy, 595, 596 oak, 595 snake, antidotes, 539 Poke weed, 455 Polariscope, micro, 764 Polemoniaceffi, 670 Polemoniales, 668 Polemonium, 455, 670, 676 family, 670 Pollantin, 726 Pollen, 120, 122, 298, 375. 404, 726 composition of, 726 method of gathering, 722 pine, 107 sac, 298 toxic, 726 tube, 1 1 1 weight of, 726 Pollination, in, 125, 397 Pollinia, 123 Polygala, 172, 455. 589 Polygalaceae, 589 Polygamous, 392 Polygamus-a-um, 456 Polygonaceae, 520, 574 Polygonales, 520 Polygonatum, 456, 483 Polygonatum, rhizome of, 325 Polygonum, 456, 525. 52? Polymnia, 720 Polynesia, 631 Polypeptides, 199 Polypodium, 456 Polypody, 456 Polyporaceae, 59 Polyporus, 456 resins in, 237 Polytrichum, 77, 78, 85 Pome, 420 Pomegranate, 447, 457, 629- Pomelos, 584 Pometia, 603 Pond lily, yellow, 531 Pond-weed family, 466 Pontederia, 482 Pontederiaceae, 480 Poplar, 456, 508 Popowia, 542 Poppy, 454, 548, 549 California, 547 celandine, 550 family, 546 horned, 446 Mexican, 547 oil, 547 in, 213 opium, 546, 547 prickly, 436 yellow, 550 Populin, 169. 170, 508 Populus, 456, 508 species, 508 Pores, bordered, 275 sieve, 276 simple, 263 water, 279 Port wine, 607 coloring of, 529 Portulaca, 551 Portulacaceae, 531 Potassium hydrate, crystals, 762 iodide, crystals, 762 Potato, 688 Chinese, 492 family, 683 phyto-globulins in, 194 plant, 688 protein in, 199 starch, 142, 148 in, 148 manufacture of, 148 with polariscope, 146 substitute, 726 Potentilla, 365, 456, 565 Potometer, 351 Pouzolzia, 517 Pratensis-e, 456 Precatorius-a-um, 456 Prefloration, 389 Prefoliation, 364 INDEX. 799 Preservatives, 755 Prickly pear, 626 Pride of China, 588 Primary root, 301 cross-section of, 310 structure, 309 of dicotyledonous roots, 345 of stem, 338 summary, 345 summary, 317 Primeverase, 658 Primeverin, 658 Primrose, 456 evening, 453, 634. 635 family, 656 Primula, 456, 656, 657 structure of flower, 407 Primulaceae, 656 Primulales, 656 Primulaverin, 658 Prince's feather, 527 pine, 644 Principes, 473 Privet, 450, 661 Procumbens, 456 Prolamins, 194, 195 Promycelium, 66 Propagation by cutting, 733 Propagative organs, 298 Prophylla, 393 Protaceae, 517 Protea, species of, 518 Proteacin, 517 Proteales, 517 Protection of plants, 172 Proteinase, 244 Proteins, 192 classification of, 193 origin of, 198 percentage of, 199 toxic, 196 Protium, 586 Protococcus, 20 Protonema, 78 Protopine, 548, 55O Protoplasm, 2, 134 Protoplasmic movement, 26 Protoplast, 2, 134 Prulaurasin, 169 Prune, 562 protein in, 200 sugar in, 156 Prunifolius-a-um, 456 Prunum, 456 Prunus, 560. 562, 565 cork of, 294 ferments in, 243 section of wood, 346 Pruriens, 456 Pseudo-^gle group, 583 Pseudococcus, 627 Pseudoinulin, 150 Pseudomonas, 307 Pseudotsuga, 114 Psidium, 632 Psoralea, 456, 574 Psyllium, 456 Ptelea, 456, 585 Ptrridophytes, 86 Pteris, 456 Pterocarpus, 456, 569, 571 Pterospermum, 615 Puber-a-um, 456 Pubescens, 456 Pubescent, 353 Puccinia graminis, 69 Puccoon, 450 Puffball, 58, 59 Pulegioides, 456 Pulegone, 234 Pulicaria, 456 Pulmonaria, 456 Pulque, 492 Pulsatilla, 456, 537 Pulse, 450 family, 567 Pulvinis, 360 Pumpkin, 454 protein in, 200 sugar in, 156 vine, 709 Punica, 457, 629 Punicaceae, 629 Purging cassia, 567 Purine, 167 Purple cone-flower, 724 gerardia, 693 Purpureus-a-um, 457 Purshia, 565 Purshianus-a-um, 457 Purslane, 531 Putamen, 410 Pycnidia, 73 Pycnoconidia, 73 Pyrenoids, 17, 149 Pyrethri Flores, 718 Pyrethron, 718 Pyrethrum, 457 Pyridine, 166 Pyrocatechol, 204 Pyrogallol, 204 Pyrola, 174 Pyrone, 180 Pyrrolidine, 166 Pyrus, 457, 562, 565 quercitin, 562 Pyxidium, 413 Pyxis, 413, 630 Quassia, 455. 457. 585, 586 Jamaica, 585 Quebracho, 667 bianco, 457 Colorado, 599 extract, tannin in, 206 Queen's root, 590 Quercitin, 169. 179, 180, 508, 512, 562. 565 Quercitrin, 170 Quercus, 457, 512 bork of, 295 galls on. 335 Quillaja, 172, 457, 564 Quill wort, 449 Quina blanca, 592 Quince. 560, 562, 565 Bengal, 451 Quinine herb, 664 Quinoline, 166 Quisqualis, 633 Raceme, 394 Racemosus-a-um, 457 Radial flower, 393 Radial-longitudinal section, 749 Radiate head, 711 Radicans, 457 Radicle, 426 Radish, 457 color in, 178 protein in, 199 Ragweed, 435, 459, 726 Rain trees, 157 Raisin, 606, 607 sugar in, 156 Rajania, 492 Ramie, 269, 517 Ranales, 531 Ranunculaceae, 532 Ranunculus, 457, 537 ferment in, 244 Rape-seed, protein in, 199 Raphanus, 457, 553 Raphia, 269 Raphides, 186 Raspberry fruit, 415 protein in, 200 red, 563 sugar in, 156 syrup of, 563 Rattle-box, 442, 575 Rattlesnake plantain, 503 Rattleweed, 574 Ravensara, 546 Ray-flowers, 395, 711 Reactions, optical, 773 Reagents. 755 alkaloidal, 163 Mayer's, 164 Sonnenschein's, 164 special, 755 Wagner's. 164 Wormley's, 165 Reaumuria, 621 Rebandin, 713 Receptacle, 375 secretory, 226 Reclinate, 364 Red gum, 574 raspberry, 563 root, 440 wine, 607 Reed, 439, 445 8oo INDEX. Refractive index. 774 Regular flower, 393 Repand, 356 Repens, 457 Reptans, 457 Reseda, 457. 554 Resedaceae, 554 Resene resins, 237 Reserve layers, 425 Resin, 236, 255 balsamic, 225 chaia, 621 fossil, 237 micro-chemistry of, 231 origin of, 238 piney, 621 soft, 587 Resinol resins, 237 Resinolic acid resins, 237 Resins, origin of, 238 Respiration, 350 Reticulate, 354, 457 Reticulatus-a-um, 457 Retuse, 355 Rhamnetin, 180 Rhamnose, 154, 562 Rhamnus, 457, 604 bark of, 342 fruit, 422 wood of, 344 Rhapontic, 457 Rhaponticus-a-um, 457 Rhatany, 449 Rheedia, 619 Rhein, 170 Rheum, 457, 521 species, 522 Rhexia, 634 Rhipsalis, 627 Rhizogenous layer, 312 Rhizome, 325 Rhizophora, 304, 630 Rhizophoraceae, 630 Rhodeose, 169 Rhododendron, 457, 646 glandular hairs in, 230 hairs in, 282 Rhodophyceae, 17, 31 Rhodymenia, 34 Rhneadales, 546, 554 Rhubarb, 457, 522 garden, 522 South China, 522 Rhus. 457, 595. 596. 597, 598 ferment in, 245 hairs of, 280, 284 poisonous, 597 species of, 597 tannin in, 206 Rhynchanthera, 634 Ribes, 457, 558 fruit. 418 Riccia. 82 Rice, 467 protein in, 199 Rice, starch in. 148 Ricin, 195, 196, 590, 611 Ricinus, 196, 457. 591 aleurone grains of, 194, 428 ferment in, 244 fruit, 410 protein in, 199 seed, 426 Ringent, 388 Riuno-kiku, 726 River-weed, 455 family, 556 Rivinia, 528 Robin, 198 Robinia, 457. 574, 576 Robinin, 169 Robustus-a-um, 457 Roccella, 74 Rocket, 447 Rockrose, 447 Rockweeds, 28 Roman chamomile, 713 Root, 299 abnormal structure of, 319 absorption, 251 adventitious, 301 aerial, 306 assimilation, 306 belladonna, 'cross- section of, 318 branches, 319 breathing, 306 cap, 299, 301 climber, 324 contraction of, 319 hairs, 299, 301, 309 inner structure of, 309 lateral, 301, 312 modified, 306 outer morphology of, 299 phytolacca, cross-section of, 318 pressure, 252 primary, 301 structure of dicotyle- dons, 345 primordia, 301 secondary, 301 stele, 313 stock, 325 tap, 301 true, 299 tubercle, 306 tuberous, 305, 327 Roripa, 553 Rosa. 457. 564 Rosaceae, 560 Resales, 556 Rose, 457, 564 apple, 632 bay, 457. 64? camphor. 564 family, 560 geranium, 579 Rose, hip, 409 oil, 564 petals, 564 tea, 629 wood, 544 Rosemary, 457 Roseus-a-um, 457 Rosin, weed, 459, 723 Rosmarinus, 457, 676 Rostratus-a-um, 458 Rotate, 388 Rottlerin, 180, 592 Rotundifolius-a-um, 458 Rubber, India, 241, 592 trees, 241 Ruberithrinic, 169 Ruber-ra-rum, 458 Rubia, 702 Rubiaceae, 697 Rubiales, 697 Rubus, 458, 563 cork in, 293 fruit, 416 Rudbeckia, 723 Rue, 458 anemone, 535 family, 581 garden, 585 meadow, 460 Ruellia, 694 Rugose, 354 Rugosus-a-um, 458 Rum, bay, 632 Rumex, 458, 523 Runner, 325 Rush, 458 bog, 449 family, 493 matting, 493 scouring, 96 soft, 493 spike, 444 wood, 493 Rust, wheat, 69 Ruta, 458 Rutaceas, 581 Rutin, 170, 585 Rye, 458, 467 lecithin in, 214 protein in, 199 starch in, 148 sugar in, 157 Sabadilla, 458 Sabal, 458, 473 Sabbatia, 664 Sabina, 1 15, 458 Sable tetraedrique, 188 Sabodilla tree, 659 Sac, pollen, 120 Saccate, 388 Saccharomyces, 47 Saccharomycetes, 47 Saccharose, 154, 155 Saccharum, 458, 467 INDEX. 80 1 Sacci, 492 Safflower, 387, 719 oil in, 213 yellow, 720 Saffron, 442, 493 meadow, 442 Safranin, as staining agent, 757 Sage, 458 garden, 676 hairs of:, 284 Sageretia, 606 Sagittaria, 465 Sago, 475 palms, 475 starch, 475 Sagrada, 440 Saigonicus-a-um, 458 Salegenin, 700 Salicaceae, 508 Salicales, 508 Salicin, 169, 170, 508 Salicylic aldehyde, 564 Salix, 458, 508 tannin in, 206 Salsify, 461 Salt, table, source of, 556 Salvia, 458, 676 hairs of, 230, 285 Samadera, 586 Samara, 420, 510, 602 Sambucus, 458, 706 cork in, 293 Sambunigrin, 169 Sanctus-a-um, 458 Sandal, oil, 518 tree, 458 wood. 458 family. 518 Sandarac, 119 Sand-box tree, 592 Sanguinaria, 458, 548, 550 latex, 241 Sanicula, 458 Santal, bastard, 581 oil, Chinese, 519 Santalaceae, 518 Santales, 518 Santalinus-a-um, 458 Santalol, 519 Santalum, 458, 518 Santonin, 719 Sap, ascent of, 252 cell, 134 Sapindaceae, 602 Sapindales, 594 Sapindus, 603 Sapium, 594 Sapodilla family, 658 Saponaria, 172, 458, 530, 531 Saponarin, 169 Saponin, 171, 575. 603, 611 occurrence of, 172 Sapotaceae, 658 Sapotilla, 659 Sapotoxin, 170 Sappan, 439 Saprolegnia, 42 Saprophytes, 40 Sapucaya nut, 629 Sarcocarp, 40, 410 Sarcophyte, 519 Sargassum, 31 Sarracenia,36i, 458, 554.555 Sarraceniaceae, 554 Sarraceniales, 554 Sarracenine, 554 Sarsaparilla, 487 wild, 637 Sassafras, 458, 544 mucilage in, 263 oil, 544 Sativus-a-um, 458 Satureia, 679 Savin, 119 Savory, summer, 679 Saxifragaceas, 556 Saxifrage family, 556 golden, 441, 556, 557 Scabiosa, 708 Scadens, 458 Scale, seminiferous, 108 Scammonia, 458 Scammony, 458 root, 669 Scarlet sumac, 597 Scatol, 519 Schinopsis, 599 tannin in, 206 Schizandra, 540 Schizogenous, 226 Schizo-lysigenous, 226 Schizomycetes, 12 Schizophyceae, 8 Schizophytes. 7 Schulze's cellulose reagent, 760 macerating solution, 761 Scilla, 458 Scillain, 170 Scirpus, 458, 472 Scitamineae, 493 Scitaminales, 493 Scleranthus, 531 Sclerenchyma, 266 Sclerenchymatous fibers, 268 Sclerocarya, 599 Sclerotium, 52 Scolopendrium, 458 Scoparia, 458 Scopolia, 684 fruit, 412 tracheae in, 274 Scopolin, 170 Scotch broom, 569 Scrophularia, 691 Scrophulariaceae, 688 Scullion, 485 Scurvy grass, 553 Scutellaria, 384, 458, 673 Scytonema, 72 Sea bean, 575 Island cotton, 610 lettuce, 25 weed, 435 protein in, 200 Secale, 458, 467 Secondary corte::, 312, 313 roots, 301 structure, 313 of stems, summary, 345 summary, 317 Secretory canals, 228 cavities, 227 cavity in pines, 107 cells, 226 Sections, 749 making of, 749 Sedge, 439, 472 Sedum, 458, 556 purpurascens, 368 Seed, 379 development of, 125 dispersal, 427 inner structure of, 427 outer morphology of, 423 pans, 729 plants grown from, 728 structure of, 424 Selaginella, 86, 98-10^' Semecarpus, 458 Sempervirens, 459 Sempervivum, 556 Seneca root, 459 Senecio, 459 Senega, 459, 589 Texas, 589 white, 589 Senegal, 459 Senna, 440, 459, 567 Alexandria, 567 American, 360 hairs of, 285 India, 567 Tinnevelly, 367 Tripoli, 567 Sepals, 120, 374, 382 Septa, 411 Septicidal, 411 Septifragal, 411 Sequoia, 117 Serenra, 459, 473 Sericeous, 354 Serotin, 169 Serotinus-a-um, 459 Serpentaria, 459, 520 Southern, 521 Serrate, 356 Serrulatus-a-um, 459 Sesame, 459 oil in, 213, 691 Sesamum, 459, 691 Seudo tanga, 119 Seven barks, 556 802 INDEX. Sexual generation, 298 spore, 298 Shaddock, 584 Shea butter, 212, 659 Sheep laurel, 648 sorrel, 524 Shepherd's purse, 439, 554 Shield fern, 437 Shikimi, 540 Shoot, 299 aerial, 329 axis, 299 creeping, 304 epigeous, 321, 322 hypogeous, 321, 325 overground, 321 subterranean, 329 underground, 321 undeveloped, 321 Shorea, 621 Shoyu, 577 Shrubs, 329 Sida, 611 Siejas, 519 Sierra Leone copal, 574 Sieve, 276 Sigillaria, 100 Silene, hairs in, 282 Silica, 202 forms of, 1 88 Silique, 420, 459 Silk, 269 dye, 625 Silkweed, 437 Silkworm, food, 517 Silphium, 723 Silver-leaf poplar, 508 Simaba, 459 Simaruba, 586 Simarubaceae, 585 Simple leaf, 348 Sinalbin, 169, 170 Sinapis, 459. 553 germination of, 299 Sindor balsam, 621 Sinensis-e, 459 Sinigrin, 169, 170 Sinuate, 356 Sisal fiber, 269 Sisymbrium, 459, 553 Skullcap, 458, 673 Skunk cabbage, 478, 480 Sleep movements, 361 Slime molds, 2 Sloanea, 609 Small nettle, 517 Solomon's seal, 483 Smartweed, 448 Smilacina, 484 Smilax, 459, 485 species of, 487 Smut, 461 corn, 67 Snakehead, 441 Snakeroot, 459 Snakeroot, black, 458. 532 Canada, 520 Virginia, 520 Sneeze-weed, 447, 723 Snow-ball, 705 Snow berry, 460, 707 Soap bark, 564, 565 berry family, 602 plants, 171 Soapwort, 458, 520 Socotrinus-a-um, 459 Soda, plants yielding, 530 Sodium in seaweeds, 28 Soft galls, 334 Soil acidity, 249 bacterium, 307 organic constituents of, 250 Soja beans, 199 Solanaceae, 683 flowers of, 385 Solanidine, 688 Solanine, 172, 684 Solanum, 385, 459, 684 fruit, 412 Solidago, 459, 521, 722, 726 Solomon's seal, 456 Solution, Scale's carmine, 760 Bohmer's haematoxylin, 760 chloral-iodine, 761 chlor-zinc-iodine, 760 copper acetate, 761 Delafield's hsematoxylin, 760 Grenadier's borax-car- mine, 760 Gienacher's haematoxy- lin, 760 Hoyer's picro-carmine,76o iodine and potassium io- dide, 761 iron, 761 phloroglucin. 761 Schulze's macerating, 761 Somnifer-a-um, 459 Sorbile, 459 Sorbilis-e, 459 Sorbit, 563 Sorbus, 459, 562 Sorghum, 459, 467 juice, percentage of sugar in, 157 Sorosis, 420 Sorrel, field, 524 sheep, 524, 525 Southernwood, 434 Soy, 577 Spadix, 394- 475 Spanish licorice, 568 moss. 481 Sparganiaceae, 463 Sparganium, 464 Spathe, 394. 478 Spathiflorae, 475 Spawn, 56 Spearmint, 384, 676, 678 plant of, 326 Special reagents, 755, 761 Specimens, mounting of, 762 Spectroscope, 764, 765 Speedwell, 462 Sperm, 5 Spermophytes, 100 Sphaerites, 192, 678 Sphaerobacteria, 13 Sphagnum, 84, 85 Sphere crystals, 678 Spicatus-a-um, 459 Spice bush, 439, 544 Spiderwort, 461, 480 Spigelia, 459, 661 tracheae of, 274 Spignel, 452 Spike, 394 oil, 679 Spikelet, 394. 469 Spikenard, 453 Spilanthes, 724 Spilanthin, 724 Spinach, 527 protein in, 199 sugar in, 157 Spinacia, 527 Spindle tree, 445 Spinose, 354 Spiraea, 459, 564 Spiral, thickening, develop- ment of, 272 Spirogyra, 18 Spleenwort, 437 Sporangia, 375 Sporangium, 4 Spores, 3 asexual, 4, 298 sexual, 4, 298 staining of, 71 swarm, 5 Sporidia, 66 Sporobolus, 467 Sporogonium, 79 Sporophylls, 375 Sporophyte, 75 embryo, 298 Spring beauty, 531 Spruce, 109, 455 beer, 119 black, 112 Douglas, 114 Norway, 119 pine, 112 white, tannin in, 206 Spurge, 445, 500, 590 Squarrosus-a-um, 459 Squash, 443 Squaw-root, 695, 696 Squaw weed, 459 Squill, 458, 461, 487 Staff tree, 440, 600 INDEX. 803 Stage micrometer, 754 Staining agents, 757 of bacteria, 16 double, 762 Stains, 755 Stalk, 348 Stamen. 120, 374. 375, 379 different types of, 380 Staminate, 392 Staminodia, 391 Staminodes, 391 Staphisagria, 459, 535 Star apple, 659 grass, 435 of Bethlehem, 485 Starch, 140, 435 assimilation, 140 botanical distribution of, 147 Brazilian arrow-root, 670 characteristics of, 145 grain, composition of, 143 development of, 141 structure of, 143 manufacture of, 148 occurrence of, 143 percentage of, 148 properties of, 145 reserve, 137, 143 seen with the micropolari- scope, 146 sweet-potato, 670 with iodine, 147 Stavesacre, 459, 535 Stem, 299, 320 branches, 320 inner structure of, 338 of dicotyledons, 338 outer morphology of, 320 primary structure of, 338 structure, abnormal, 344 dicotyledonous, 339 primary, summary, 345 secondary, summary, 345 underground, 325 Sterculia, 615 seeds, 615 Sterculiaceae, 612 Sterilization. 15 Stick-lac, 238 Sticta, 73 Stigma. 120. 376, 378 different types of. 377 epithel, 406 structure of, 405 Stillingia, 459. 590 Stinck weed, 460 Stinging nettle, 517 Stink-wood, 546 Stipa. 472 Stipe of fungi, 57 Stipules, 348 function of, 348 Stitch-wort, 531 St. John's bread, 440, 576 wort, 448 family, 620 Stolon, 325 Stoma, 279 Stomata, 278, 367, 368 on leaves of Beta, 367 Stonecrop, 458 common mossy, 556 ditch, 556 Virginia, 556 Stoneworts, 26 Storax, 460, 559, 660 Stramonium, 460, 684 fruit, 409, 412 hairs of, 284 seed, 428 transverse section of mid- rib. 366 Strawberry, 445, 566 fruit, 409, 415 garden, 566 protein in, 200 wild, 567 Striatus-a-um, 460 Strigose, 354 String beans, 199 Strobile, 375. 420 Strobiles, 375 Strophanthin, 169. 170, 171 Strophanthus, 460, 666 haiis of, 284, 285 Strophiole, 427 Structure, basis of, I of wood, 347 primary, 254, 309 summary, 317 secondary, 254 summary, 319 stem, classification of, 341 primary, summary, 345 Strychnine crystals, 769 Strychnos, 460, 661 Stryphnodendron polyphyl- lum, tannin in, 206 Style, 120, 376, 378 structure of, 406 Styloids. 183 Stylophorine, 550 Stylophorium, 550 Styracaceae, 660 Styraciflua, 460 Styrax, 460, 558, 660 Suberin, 257, 290 Suberose, 257 Sublimable principles, 173 Succisa, 708 Succory, 441, 716 Sucrose, 155, 527 Sugar, 154 beet. 527 protein in, 199 bush. 518 cane, 467 Sugar, cane, juice, percentage of sugar in. 157 in cereals, percentage of, 156 in plants, 156 in vegetables, 156 Sumach, 457, 595 poison, 597 scarlet, 597 tanner's, 595 Sumbul, 639 Summer savory, 679 Sundew, 361 444, 554 Sun-dial, 451 Sun-flower, 712 oil in, 213 seed-cake, 725 seed, protein in, 199 Sun's energy, 138 Suppressed, 391 Surface of leaves, 353 Suringi, India, 620 Survival of the fittest, 131 Suspensor, 125 Suture, dorsal, 377 ventral, 377 Swamp pink, 485, 490 Sweet, 444 almond, protein in, 199 anise oil, 643 balm, 679 basil, 679 cicely, 643 fern, 509 flag, 479 gale, 509 gum tree, 450, 558 marjoram, 679 pea, 576 potatoes, protein in, 199 percentage of sugar in, 157 starch, 670 vine, 669 scabious fleabane, 713 William, 531 wine, 607 Swertia, 460, 664 Swietenia, 589 Sycamore. 559 Syconium, 420 Sylvaticus-a-um, 460 Sylvestris-e, 460 Symmetrical, flower, 392 Sympetala?, 643 Sympetalous, 385 Symphonia, 620 Symphoricarpos, 460, 707 Symphytum, 460, 671 Symplocarpus, 478, 480 Synantherin, 150, 726 Syncarpous, 376 Synergids, 124 Syngenesious. 382 Synura, n 804 INDEX. Syringa, 455, 460, 66r Syringin, 169, 661 Syringopicrin, 661 Tabacum, 460 Table salt, source of, 556 Tacamahac, 439, 508, 613 Bourbon, 618 Brazilian, 618 India, 618 resins, 587 West Indian, 587 Tagetes, hairs in, 288 Talauma, 540 Tallow tree, Chinese, 594 Tamaricaceae, 621 Tamarindus, 460, 569 Tamarix, 621 Tamonea, 634 Tamus, 492, 709 Tanacetum, 460, 720 Tangential-longitudinal sec- tion, 749 Tangkawang, 621 Tanner's sumac, 595 Tannides, 202 Tannin, 202 chemical properties of, 203 distribution of, 205 idioblast, 207, 208 in galls, 335 micro-chemistry of, 204 pathological, 207 physiological, 207 Tannol resins, 236 Tansy, 460, 720 Tapetum, 121 Tapioca starch, 594 Tap-root, 301 Tapura, 606 Taraktogenos kurzii, 214 Taraxacum, 239, 387, 460 Taxus, 113 Tea, 460, 617 Appalachian, 600 black, 618 Brazilian, 600 caffeine in, 162 cassine, 600 chests, 625 culture, 746 family, 617 green, 618 Labrador, 450 New Jersey, 605 Paraguay, 600 germination of, 730 plant, 615 rose, 629 seed, oil in, 213 substitute, 531, 634 tree, 617 Teaberry, 650 Teak-tree, 673 Teak-wood, 673 Teasel. 444, 707 Technique, bacteriological, 14 Tecoma, 691 Tectona, 673 Tegmen, 425 Telegraph plant, 361 Teleutospores, 68 Temperature, 247 Tendril, 323 climber, 324 Tephrosia, 575 Terebinthina, 460 Terminalia, 633 Terpenes, 233 Terpinene, 679 Terpineol, 632 Terra silicea purificata, 38 Testa, 425 Testing of drugs, 248 Tetradynamous, 381 Tetragonal crystals, 183 Tetrameles, 625 Tetrapanax, 636 Teucrium, 460 Texture of leaves, 354 Thalictroides, 460 Thalictrum, 460 Thallophytes, 6 Thallus, 6 Thea. 460, 616 Theaceae, 617 Thein, 173, 176 Thelephoraceae, 59 Theobroma, 460, 612 Theobromine, 612, 618 Theophylline, 618 Thistle, 712, 723 blessed, 442 milk, 451 star, 440 Virgin Mary's, 451 Thlaspi, 553 Thorn apple, 684 Thoroughwort, 445, 712 Thuja, 1 1 8, 460 Thujone, 719 Thyme, 460 field, 441 garden, 677 Thymelaea, 628 Thymelaeaceae, 627 Thymol, 234, 678, 681 Thymo-quinhydrone, 179 Thymoquinone, 179, 681 Thymus, 460 Tiarella, 460, 556 Tibouchina, 634 Tick Trefoil, 443 Tilia, 461, 608, 609 hesperidin in, 153 species of, 609 Tiliaceae, 609 Tillandsia, 480 Tinctorium, 460 Tinctorius-a-um, 460 Tissue, 121 conjunctive, 313 laticiferous, 296 mechanical, 264 milk, 296 Tobacco, 453, 460, 688 camphor, 688 Indian, 710 Persian, 688 plant, Virginia, 688 Turkey, 688 wild, 710 Tococa, 634 Toddy, 620 Tolu, balsam of, 572 Tolu-resinotannol, 572 Toluifera, 461, 572 Tomato plant, 688 sugar in, 157 Tomentose, 354 Tomentosus-a-um, 461 Toothed, 385 Toringin, 562 Tormentilla, 565 Torus, 375, 389 Touch-me-not, 448 Touranose, 155 Tous les mois, 496 Toxalbumins, 196, 726 Toxicodendrol, 595 Toxicodendron, 461 Toxylon, 516 Tracheae, 273, 313 markings of, 273 Tracheids, 275 Trachylobium, 574 Tradescantia, 461, 480 Tragacanth, 218, 461, 569, 570 Tragopogon, 461 hairs in, 288 Trailing mahonia, 537 Transpiration, 350 Transverse heliotropism, 349 section, 749 Trapa, 634 Treacle mustard, 553 Tree of heaven, 434 Trees, 329 green coating on, 21 Trefoil, clover, 461 bird's foot, 450 Trehalose, 155 Tremellaceae, 59 Triandrus-a-um, 461 Triassic period, 101 Trichodesmium, 8 Tricolor, 461 Tricuspidatus-a-um, 461 Trifolium, 461, 576 Trilisa, 461 Trillium, 461 Trimorphic flowers, 399 Triosteine, 707 INDEX. 805 Triosteum, 706 Triphyllus-a-um, 461 Tristichous, 363 Triticum, 461, 467, 468 Trivial, 461 Trivialis-e, 461 Tropasolaceae, 579 Tropaeolum, 579 True root, 299 Solomon's seal, 483 Truffles, 65 Trumpet -creeper, 691 Truncate, 355 Tsuga, 113, 118, 461 Tuber, 326 Tubercle, root, 306 Tuberin, 195 Tuberose, 485 Tuberosus-a-um, 461 Tubiflorae, 668 Tubular flowers, 711 Tuckahoe, 65 Tulip, 485 bulb, 330 tree, 450, 539 Tupelo, 453, 5i8 Tumeric, 494 Turmerol, 496 Turnera, 623 Turneraceae, 623 Turnip, 438, 553 Indian, 436 little, 453 protein in, 199 sugar in, 157 Turpentine, 118, 460 as a clearing agent, 757 Canada, 118 Strassburg, 119 Venice, 118 Turpeth, 461 root, 453 Turpethum, 461 Turtlehead, 441, 691 Tussilago, 387. 461, 723 Twin leaf, 449 Twiner, 324 Types of mestome strands, 343 Typhaceae, 463 Ulex, 575 Ulmaceae, 512 Ulmaria, 461 Ulmus, 461 section of wood, 346 species of, 512 Ultra-microscope, 765 Ulva, 25 Umbel, 394, 636 Umbellales, 636 Umbellated, 461 Umbellatus-a-um, 461 Umbelliferae, 575, 636 fruit of, 417 Umbelliflorae, 636 Umbellularia, 461, 544 Umbrella tree, 540 Unguis, 385 Unifacial leaf, 366 Uniflorus-a-um, 461 Unisexual, 444 flower, 392 Unona, 542 Upas-tree, 516 Uragoga, 699, 700 Urari poison, 517 Urceolate, 388 Uredineae, 65 Uredospores, 69 Urena, 611 Urginea, 461, 487 Uroglena, 8, 10 Urtica, 461, 51? Urticaceae, 517 Urticales, 512 Use and disuse, 131 Usitatissimus-a-um, 461 Usnea, 73 Ustilagineae, 65 Ustilago, 67, 461 Utricle, 420, 527 Utricularia, 299 Uva-ursi, 461, 644 Uvularia, 485 Vaccinium, 174, 653 fruit, 417 Vacuole, 134 Valerian, 462, 707 garden, 707 Greek, 671 wild, 707 Valeriana, 462, 707 Valerianaceae, 707 Valerianales, 707 Valerianella, 707 Vallea, 608 Valonia, tannin in, 206 Valvate, 389 Vanilla, 462, 497 grass, 472 hairs of, 284 leaf, 461 sugar in, 157 Vanillin, 173, 572 Variifolius-a-um, 462 Various woods, coarse struc- tures of, 346 Varnish tree, 597 Vasicine, 696 Valeria, 621 Vatica, 621 Vaucheria, 22, 40 Vegetable agglutinins, 198 bezoars, 577 butter, 659 ivory, 473. 474 Vegetative organ, 299 Veins, 352 Venalion in Dicotyledons, 353 Monocotyledons, 352 leaf, 352 Venenosus-a-um, 462 Ventral palisade tissue, 366 suture, 377 Venus's fly-trap, 362, 554 Veratrum, 462, 485 section of root, 320 Verbain, blue, 674 Verbascum, 691 hairs of, 286 hesperidin in, 153 Verbenaceae, 673 Verbenas, 673. 674 Vermilion, 597 Vernation, 364 Veronica, 462, 689 Verrucose, 354 Versatile, 380 Versicolor, 462 Verticillatus-a-um, 462 Verus-a-um, 462 Vervain, 673 nettle-leaves, 673 Vessels, 273, 313 Vetchling, 450 Viburnum, 462, 704, 705 Vicia faba, 199 Vicianin, 169 Vicilin, 195 Victoralis, 462 Victoria, 532 Vignin, 195 Villosus-a-um, 462 Vinca, 668 Vinifer-ra-rum, 462 Viola, 462, 622 glandular hairs in, 230 leaf of, 348 quercitin, 622 stem in section, 336 stomata in, 278 structure of flower, 403 Violaceae, 622 Violet, 462 dog's tooth, 485 English, 622 family, 622 leaf of, 348 sweet, 622 Virginia creeper, 607 grape-fern, 365 Virginianus-a-um. 462 Virginicus-a-um, 462 Viridiflorus-a-um, 462 Viridis-e, 462 Virosus-a-um, 462 Viscine, 518 Viscum, 518 Vismia. 619, 620 Vitaceae. 606 Vitae, arbor, 460 Vitis, 462. 607 Vittae, 637 8o6 INDEX. Volvox, 21 Vouacapoua, 436, 462 Vulgaris-e, 462 Wahoo, 600 Wake-robin, 437, 461 Walking leaf, 439 Wall, composition of, 254 kinds of, 258 marking of, 260 mucilage, 257 origin of, 254 pepper, 556 thickening of, 260 Walnut, 449, 509 black, 509 English, cross-section of wood, 346 family, 509 oil in, 213 white, 509 Waltheria, 615 Wandering Jew, 480 Washingtonia, 643 Water, 247 arum, 439, 479 cress, 553 fennel oil, 643 hemlock, 575, 642 iodine, 761 leaf family, 670 lily family, 531 melon, 710 net, 22 plantain, 466 pores, 279 Wax, 210, 216, 277 carnauba, 2, 4 crystalline, 216 forms of, 216 Japan, 212 myrtle, 211, 212, 509 ocotilla, 621 opium, 214 Wheat, 461. 467 grass. 434 lecithin in, 214 protein in, 199 starch in, 148 sugar in, 157 White clover, 472 White clover, colors, 178 wines, 607 Whortleberry, 654 Wild black cherry, 560 brier, 564 caper, 591 cherry, 561 indigo, 573 marjoram, 679 strawberry, 566 yam root, 492 Willow, 458, 508 herb, 440, 634 flowers, 400 Wind flower, 436 Wine, 607 light colored, 607 mammey, 620 port, 607 red, 607 sweet, 607 white, 607 Winterana, 622 Winteranaceae, 622 Winter cress, 438 Wintergreen, 644, 650 Winterin, 540 Winter's bark, 540 Wistarin, 575 Wisteria, 462, 575 Witch-hazel, 447, 558, 559 Witch's brooms, 334 Wolfsbane, 434 Wood, 317 bass, 461 carving, 117 fibers, 270 in coal, 119 pulp, 117 red, 117 rush, 493 sorrel, 454. 544, 579 structure of, 346 Woodfordia, 628 Woodruff weed, 437 Wool, 269 Woolly, 354 Wormseed, 527 Spanish, 527 Wormwood, 434, 437, 719 hairs of, 285 Xanthium, 462, 723 Xanthone, 180 Xanthorhamnin, 169, 170 Xanthosome, 480 Xanthostrumarin, 723 Xanthoxylum, 462, 582 Xerase, 49 Xylem, 312 Xylopia, 541, 542 Xylose, 169 Xyrideales, 480 Yam, 444, 492 root, wild, 322, 492 Yarrow, 434, 452 Yeast, 47 dry, lecithin in, 214 glycogen in, 154 Yellow gum, 574 pond lily, 434, 531 Yerba Mate, 60 1 Santa, 670 Yew, 113 Ylang-ylang, 542 Yohimbi bark, 702 Yohimbihi bark, 702 Yohimbine, 702 Yucca, 485 Zanthoxylum, 581, 582 Zanzibar copal. 574 Zea, 462, 467, 469 root-tip, 300 Zeora, 75 Zeridine, 49 Zeylonicus-a-um, 462 Ziehl's carbol-fuchsin, 757 Zingiber, 462, 494, 495 Zingiberaceae, 494 Zizyphus, 606 Zollikoferia, hairs in, 282 Zoo-cecidien, 335 Zoospores, 5 Zostera, 466 Zygadenus, 574 Zygomorphic, 393 Zygomycetes, 42 Zygophyllaceae, 581 Zygospore, 5 Zymase, 244 7 I