Araceae

“ V. Genus; VI. Species.
To illustrate: The white pine belongs to the highest great division (sub-kingdom) of the plant kingdom. The plants of this division all produce seeds, and hence are called “spermaphytes” (“seed plants”) . They may be divided into two groups (classes) , distinguished by certain peculiarities in the flowers and seeds. These are named respectively “gymnosperms” and “angiosperms,” and to the first our plant belongs. The gymnosperms may be further divided into several subordinate groups (orders) , one of which, the conifers, or cone-bearing evergreens, includes our plant. ”

“ Each head is surrounded at its base by one or more series of usually tightly overlapping bracts, incorrectly called a calyx by the unobservant. The Compositæ include over 900 genera and 11,000 species from all parts of the world. Most of them in America are herbs. Daisy, dandelion, dahlia, chrysanthemum, sunflower, boneset, chicory, lettuce, and scores of other examples could be cited, all herbs. In the tropics the Compositæ are more often trees and shrubs. The family contains many economic plants such as arnica, chamomile, artichokes, inula, and many others. ”

“ The roots of air-plants, such as certain orchids, draw their nourishment from the air.
The experiment of marking roots and stem has been already tried, but it should be repeated. Repetition of experiments is always desirable, as it fixes his conclusions in the pupil's mind. The stem grows by a succession of similar parts, phytomera, each part, or phyton, consisting of node, internode, and leaf. Thus it follows that stems must bear leaves. The marked stems of seedlings show greater growth towards the top of the growing phyton. It is only young stems that elongate throughout. ”

“ In this Natural Order, we find fruits and seeds, of very different sizes as well as shapes, but fortunately they are so similar in species of the same genus, that a gardener who is not learned in botany, after having seen one of each, may have a tolerable guess, at the genus of any new ones, he receives from abroad. In sowing them, much must be left to the discretion of the gardener; generally they ought not to be buried deeper than half an inch in the earth, nor closer to each other, than from a quarter of an inch to an inch, according to their size ”

“ For want of due discrimination, as Miller has before observed, Nurserymen are apt to collect and mix with this species the seeds of another, viz. the amara, and which persons not much skilled in plants consider as the white variety; but a slight attention will discover it to be a very different plant, having smaller and longer heads, differing also in the shape of its leaves and seed vessels, too trifling a plant indeed to appear in the flower-garden. ”

“ The flowering plants have several distinct and visible organs for the formation and fertilization of their seed, to each of which is assigned a special and necessary office. In the flowerless section, on the contrary, there are none of these visibly separate agencies in reproduction, and what are usually termed the seeds do not show any parts representative of the developed product. In the true seeds, which belong to flowering plants alone, are contained the rudiments of a stem, leaves, and root, but in the spores of the flowerless plants nothing of the kind is found. ”

“ The orchids are mostly small or moderate-sized plants, few of them being more than a metre or so in height. All of our native species, with the exception of a few from the extreme south, grow from fibrous roots or tubers, but many tropical orchids, as is well known, are “epiphytes”; that is, they grow upon the trunks and branches of trees. One genus, Vanilla, is a twining epiphyte; the fruit of this plant furnishes the vanilla of commerce. ”

“ The question as to which groups among the Flowering Plants [Angiosperms] are to be considered as relatively primitive, is still, at the present day, an open one, but it would be generally conceded that Bauhin’s arrangement cannot be accepted. There is little doubt, from the standpoint of modern botany, that the Grasses are a highly specialised group, while the “tree habit” has been adopted independently by many plants belonging to entirely different cycles of affinity, and thus, except in rare cases, it cannot be used as a criterion of relationship. ”

“ As they grow taller, the lower leaves, even on a healthy plant, generally drop off.
LEGGY PLANTS. It is a good way, when these and kindred plants become “leggy,” to improve their appearance by cutting off the old root, and making them root higher up the stem. Where the plant is valuable, it is best to be sure of new roots before throwing away the old, but, as a rule, aralias have so many joints that they may easily be induced to strike by just pressing the stem firmly into the soil, then putting the pot in some dark place, and keeping the soil rather dry, though the foliage must be kept moist. ”

“ When these layers, so thick and succulent, have given up their store to the growing parts within, they are left as thin and dry husks. In a Houseleek, an Aloe or an Agave, the green color of the surface of the fleshy leaf indicates that it is doing the work of foliage; the deeper-seated white portion within is the storehouse of the nourishment which the green surface has elaborated. So, also, the seed-leaves or cotyledons are commonly used for storage. Some, as in one of the Maples, the Pea, Horse-chestnut, Oak, etc., are for nothing else. ”

“ He begins by distinguishing Herbs, Shrubs, and Trees. Proceeding to the detailed classification of Herbs, he divides them into Imperfect "which either do want or seem to want some of the more essential parts of Plants, viz. either Root, Stalk, or Seed," the Cryptogamia of Linnaeus; and Perfect "having all the essential parts belonging to a Plant." The Perfect Herbs are arranged in three main groups according to (1) their leaves, (2) their flowers, (3) their seed-vessel, each group being subdivided in various ways. ”

“ In these the axis remains short, nearly as it is in the bud; the leaves therefore remain close together in sets or circles; the outer ones, those of the calyx, generally partake more or less of the character of foliage; the next set are more delicate, and form the corolla, while the rest, the stamens and pistils, appear under forms very different from those of ordinary leaves, and are concerned in the production of seed. This view gives to Botany an interest which one who merely notices the shape and counts the parts of blossoms, without understanding their plan, has no conception of. ”

“ The plant may at once be recognized by the heart-shaped pods and small, white, four-petaled flowers. The plant begins to flower when very small, but continues to grow until it forms a much-branching plant, half a metre or more in height. On pulling up the plant, a large tap-root (Fig. 93, A, r) is seen, continuous with the main stem above ground. The first root of the seedling plant continues here as the main root of the plant, as was the case with the gymnosperms, but not with the monocotyledons. ”

“ Each leaf is traversed by two fibro-vascular bundles of entirely different structure from those of the ferns. Each is divided into two nearly equal parts, the wood (x) lying toward the inner, flat side of the leaf, the bast (T) toward the outer, convex side. This type of bundle, called “collateral,” is the common form found in the stems and leaves of seed plants. The cells of the wood or xylem are rather larger than those of the bast or phloem, and have thicker walls than any of the phloem cells, except the outermost ones which are thick-walled fibres like those under the epidermis. ”

“ Annual or perennial herbs, trees, or shrubs, with acrid often pungent juices, alternate or rarely opposite leaves, regular or irregular usually perfect flowers in terminal cymes or racemes or solitary, numerous ovules inserted in two rows on each of the two placentas, capsular or baccate 1-celled fruit, and seeds without albumen. A family of thirty-four genera, mostly confined to the warmer parts of the world and widely distributed in the two hemispheres. Of the seven genera which occur in North America only one has an arborescent representative. ”

“ Embryo thread-shaped, spirally coiled in the rather fleshy albumen, destitute of cotyledons, sometimes with a few alternate scales (belonging to the plumule) ; germination occurring in the soil.—Leafless annual herbs, with thread-like yellowish or reddish stems, bearing a few minute scales in place of leaves; on rising from the ground becoming entirely parasitic on the bark of herbs and shrubs on which they twine, and to which they adhere by means of suckers developed on the surface in contact. Flowers small, cymose-clustered, mostly white; usually produced late in summer and in autumn. ”

“ In most species the fertile and sterile shoots are alike, both being green and leaf-bearing, but in a few species the fertile are more or less different, e.g. in E. arvense the fertile shoots appear first, in the spring, and are unbranched and not green. Any portion of the underground rhizome when broken off is capable of producing a new plant; hence the difficulty of eradicating them when once established. There are 24 known species of the genus which is universally distributed. ”

“ As soon as the arum, with its sprouting head, has raised its first leaves far enough above the ground to reach the sunlight, it begins to form fresh starches and new leaves for itself, and ceases to be dependent upon the store laid up in its buried lobe. Most seeds accordingly contain just enough material to support the young seedling till it is in a position to shift for itself; and this, of course, varies greatly with the habits and manners of the particular species. ”

“ A very small family, of only two genera, one North American, one Japanese; aromatic shrubs, with opposite, toothless leaves, with short leaf-stalks, without stipules; flowers large, solitary, at the ends of leafy branches; sepals, petals, and stamens, indefinite in number, in many, overlapping series, passing one into the other, so that one cannot tell which is which, and all borne on the receptacle, which is hollow, resembling a rose-hip, almost enclosing the numerous pistils; stamens short, the inner ones without anthers ”

“ In garden flowers, also, we see most striking results of continuous selection. By taking advantage of the tendency of stamens and carpels to change occasionally into petals, and of petals to increase in number, “double flowers” have been effected. When “doubling” is complete—that is, when the conversion into petals is thorough—no seed can of course be produced, and the plants must be propagated by cuttings. Different other slight natural variations, exaggerated by selection and cultivation, have been the source of innumerable “varieties” in our gardens. ”

“ Phyllotaxy of Alternate Leaves. Alternate leaves are distributed along the stem in an order which is uniform for each species. The arrangement in all its modifications is said to be spiral, because, if we draw a line from the insertion (i. e. the point of attachment) of one leaf to that of the next, and so on, this line will wind spirally around the stem as it rises, and in the same species will always bear the same number of leaves for each turn round the stem. That is, any two successive leaves will always be separated from each other by an equal portion of the circumference of the stem. ”

“ If any plants ought to be removed from these Classes, they must be such as have the structure of all the accessory parts of the flower exactly alike, (the essential parts, or stamens and pistils only, differing,) in both barren and fertile flowers; and especially such as have in one flower perfect organs of one kind, accompanied by rudiments of the other kind, for these rudiments are liable occasionally to become perfect. By this means dioecious species of a genus, as in Lychnis, Valeriana, Rumex, &c., would no longer be a reproach or inconvenience to the system. ”

“ In Arisæma (Fig. 86, A) the flowers are borne only on the base of the spadix, and the plant is diœcious. The flowers are of the simplest structure, the female consisting of a single carpel, and the male of four stamens (C, D) . While the individual flowers are destitute of a perigone, the whole inflorescence (cluster of flowers) is surrounded by a large leaf (spathe) , which sometimes is brilliantly colored, this serving to attract insects. The leaves of the aroids are generally large and sometimes compound, the only instance of true compound leaves among the monocotyledons (Fig. 86, B) . ”

“ They have hollow stems, with partitions at the nodes; the leaves consist only of a whorl of scales at each node, these coalescent into a sheath: from the axils of these leaf-scales, in many species, branches grow out, which are similar to the stem but on a much smaller scale, close-jointed, and with the tips of the leaves more apparent. At the apex of the stem appears the fructification, as it is called for lack of a better term, in the form of a short spike or head. This consists of a good number of stalked shields, bearing on their inner or under face several wedge-shaped spore-cases. ”

“ Certain genera of plants, which, like the brambles, roses, and willows in Europe, consist of a continuous series of varieties between the terms of which no intermediate forms can be intercalated, may be supposed to be newer types and on the increase, and therefore undergoing much variation; whereas genera which present no such perplexing gradations may be of older date and may have been losing species and varieties by extinction. ”