by small filaments of ice which immediately unite: we at first see lines extremely fine, from which others proceed, which in their turn produce fresh filaments resembling those which grow from a quill. When the frost is strong and the first crust of ice is thickened, the most beautiful foliage and lines of various kinds are produced. Botany. Mr. B. The definition or short description of a plant to distinguish it from an animal or mineral, has been given by several authorities. Although they vary on some points they generally agree on the whole. Dr. Thomson says that "a plant is a living organised body, which requires food and air for its support, grows, propagates its species and dies; and differs from animals in being nourished by continued absorption by its external surface." This definition is sufficiently comprehensive and just, and had the word absorption, which here implies an active rather than a passive principle, been changed into one implying that a plant is a recipient only, the definition would, perhaps, have been as correct as it is concise. As Linnæus is also an authority worthy of notice I give his definition, which is as follows:-"Stones grow, plants grow and live, animals grow, live and feel." This definition, though plausible, is defective. For stones do not grow in the exact sense in which plants and animals grow, and as we are possessed of no criterion by which we may infallibly judge of the existence of the faculty of sensation, the difficulty of decision remains as before. The following is the most rational definition to mark distinctly the boundaries of the three kingdoms of nature. A mineral is a mass of lifeless matter, inorganic, inert, insentient, not augmentable by nutrition, but attaining its bulk merely by the external or mechanical, or chemical apposition (addition) of new parts or particles. A vegetable is a living organised body, incapable of locomotion, insentient, but springing from and producing a germ that is augmentable by nutrition, being usually fixed to the soil or other appropriate substances of support, by a root or disk, or but very rarely free, and deriving its aliment from the fluids of the medium in which it grows. An animal is a living and organised being, self-moving, sentient, springing from and producing a germ that is augmentable by nutrition, and ranging in search of aliment (food), which, with the exception of the infusoria (a class of small worms, comprehending those minute animalcules which can not be traced except by the aid of the microscope) it takes up chiefly in a solid state and subjects to the action of the digestive organs. For the young gardener, who is an intelligent observer and a good botanist, there is no solitude, every flower he observes excites in him curiosty and interest, wherever he wanders he finds plants which will amply reward his most attentive examination, and as soon as he comprehends the manner of their structure, and the rank they hold in the system of nature, he enjoys an unalloyed pleasure, not less vivid because it costs him neither expense nor anxiety. The variety of seasons, with their successive productions, is to him a diversified panorama, a continually shifting scene which always affords gratification and instruction. -Not a tree, A plant, a leaf, a blossom, but contains A folio volume, he may read and read, And read again, but still find something to instruct, In short, his investigations into every, the most minute, part of the vegetable kingdom will exalt his conception of the Supreme Being, of whose wisdom, power and goodness it affords most striking exemplifications. Let us now examine the structure of some plant in which is present every organ that is usually to be met with in what we consider a species in all its parts. Such a plant is the violet (viola odorata) or this heartsease (viola tricolor), which I hold in my hand. You can see that it consists of a number of parts arranged symmetrically upon a green angular axis, which puts forth under ground many slender whitish threads, divided in an irregular manner, these slender threads are the roots, and the green angular part rising from the roots is the stem, upon this stem are placed, at equal distances, those flat, green, toothed bodies which gradually taper into a thin stalk, it is almost unnecessary to tell you that these are leaves. At the base of each leaf are two other green parts which are like the leaves only they are smaller and deeply gashed near the bottom, instead of tapering into a stalk, to these is given the name of stipules. The axis consisting of stem and root, together with the leaves and stipules, forms the organs of vegetation; so named because they have no other destination than to enable the plant to live and grow, and to perform those vital actions which are not connected with the office of spontaneous propagation. From the angle formed by the junction of the leaf with the stem, which is called the axil, springs a slender angular L stalk, on the top of which the flower is seated. This stalk, called the peduncle, has, near its upper end, a couple of little scales named bracts, which are of a nature intermediate between the organs of vegetation and those of fructification. The latter name is given to the parts of a flower, because their office is exclusively to enable a plant, by fructifying, to multiply its species spontaneously. The flower consists, externally, of five small, narrow, green leaves, called sepals, and of the same number of larger yellow and purple leaves called petals; the sepals taken collectively form a calyx, and the petals, in like manner, form a corolla. These two are often named floral envelopes. Within the petals, and quite hidden from view by the bases of these organs, until they are pulled off, is a row of five thin, pale yellow parts, sticking together a little by their edges, but separated from the body they surround; they are named stamens, and are the fertilizing apparatus of the flower. They surround a hollow body tapering into a zigzag cone, and terminating in a globular head; this is the fructifying apparatus, and is called the pistil; within its hollow case may be found the young seeds, which we name ovules, from their resemblance to little eggs. By certain curious operations, which I shall explain in a future lesson, the pistil is fertilized, after which it swells, alters its form and texture, and at last becomes the fruit, which is hard and dry, splits into three pieces, and sheds the seeds which by that time are ripe and fully formed. The seed consists of a shell, containing a quantity of fleshy matter, from its resemblance, in use, to the white of an egg, called albumen, in the midst of which lies an embryo plant, which is supposed to be nourished by the albumen until it breaks the shell and is strong enough to gain its food for itself. Such is the heartsease; such are the organs which constitute the fabric of all the most perfectly constructed plants. Lowly a species as it is, it comprehends every part that is employed by nature in the formation of the loftiest tree of the forest; the difference in size between it and a tree being caused by nothing more than an endless multiplication of similar parts of vegetation, constructed always upon a similar plan, adjusted to each other in the most admirable manner, and all working in perfect harmony and order. Although all the parts just named concur in the formation of a plant of the most perfect kind, there is not one of them that, in one species or another, is not either altogether wanting, or so altered in its nature as scarcely to be recognised. The root itself by which the food is conveyed into the body, is scarcely present in such marine plants as sea weeds, and even in the dodder (cuscuta) which grows upon heaths, and the misletoe, which fastens itself as a parasite upon other species is so rudimentary as to be scarcely capable of action. The stem in numerous species is so short as to be almost invisible. Leaves are frequently mere scales which drop off almost as soon as they are formed, leaving the plant to shift for itself by the aid of other means, as is the case in cactuses, stapelias, and the like. Both leaf and stem are so blended into one body in the duck-weed (Lemna) that it is difficult to say whether the part that really exists is the one or the other. Stipules are as often wanting as present. Bracts, in like manner, are frequently missing. Of the floral envelopes, sometimes the corolla is absent, as in the mezerion; and sometimes both calyx and corolla, as in the willow. Even the stamens and pistils themselves disappear in a large number of plants. It is, however, to be remarked that this latter circumstance is always attended with a corresponding imperfection in the whole of the other organs, and is, therefore before all other things, considered an indication of a greater degree of general imperfection. Ferns, for instance, in which this occurs, have neither calyx nor corolla, nor is their stem like that of other plants; in mosses, moreover, the leaves are mere scales; in lichens the whole plant consists of but a flat plate composed of leaf and stem combined with nothing for their seeds but excessively minute transparent bladders; and finally, some confervæ and fungi are destitute at once of every one of the usual organs, consisting of nothing but a cell or two of exceedingly small size, in which the essence of root, stem, leaf, flower, and fruit, without the form, is supposed to be comprehended. The surface of all parts of plants, except the stigma and spongioles, is covered, at least, when young, with a thin skin, which may easily be detached, especially from the leaves, and most readily after these organs have been allowed to macerate for a few days in water. This skin is termed the epidermis, or cuticle, and when placed under the microscope it exhibits a delicate net-work, whose meshes are either quadrangular, hexagonal, or of other many sided forms, or else they are irregularly bordered by waved and sinuous lines extending over the whole surface; very frequently also a set of pores may be observed, having a sort of glandular border which are scattered over the epidermis at intervals, these pores are termed stomata. From the surface of the skin often arise little processes, which, in fact, are mere expansions of it, to which is given the name of lymphatic hairs, or more commonly, hairs only, from their resemblance in appearance to the down or hair of animals; stings are stiff needle-like hairs which arise from a thick swollen base full of chambers in which the poison they secrete is collected and stored up. Prickles (Aculei) are hairs of a larger growth, they are hard, horny, sharp-pointed, conical, and often hooked excrescences, which rise from the surface of the stem, from whence they may be easily broken off, when young they are small, soft, and green. As the surface of a stem distends in consequence of the expansion of its inside, the base of the prickles enlarges, and, at the same time, they harden, till at last they become the large stiff bodies to which the name is applied; on the branches of the rose this their progress may be easily followed. When they are full grown they can no longer adjust themselves to the distending surface on which they are planted, and are consequently thrown off; this is the reason why it is the young branches of plants only that are prickly, the old stems being almost always unarmed. English Grammar. Mr. B. According to most grammarians there are three cases of nouns in the English language, namely, the Nominative, the Possessive, and the Objective. The Nominative case simply expresses the name of a person or thing, which is the subject of a sentence, or part of a sentence. In the sentences John mows quickly, or Jane laughs heartily, or Thomas trenched the ground, John, Jane, and Thomas are the nominatives, they being the names of persons about whom we speak. The Nominative case of a noun is its ordinary form, whether singular or plural, as the man was there, or the men were there. In examining the form of a sentence the principal point is to find out the nominative case. And in order that you may be able to tell quickly what is the subject of any sentence or part of a sentence, it will be well to examine a number of sentences, beginning with those that are short and easy. The Nominative may be known by asking the question who, which, or what. For example :-in the sentence toads are very useful, ask who are useful, answer-toads; therefore toads is the nominative. Try another sentence, the hat is mine, ask what is yours, answer-the hat, the hat therefore is the nominative, that being the thing about which you speak. In the following sentences the word forming the nominative is printed in italic (slanting) letters. William improves very much. Jane grows a fine girl. |