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"The oak-tree was an acorn once, that fell upon the earth;
8. The oak-tree and the date-palm, different as they are in structure and appearance, are not more unlike than the acorn and the date seed. The most careless observer must have noticed the difference between a bean or pea and a kernel of wheat or corn, as well as in the leaves and stems of the plants themselves. Acorns, beans, and peas are easily split or divided into their two lobes; while the date seeds and grains of wheat and corn seem to consist of a single mass, which is with more difficulty split or broken.
9. The more careful observer has noticed that the stem, leaves, and external covering of plants growing from twolobed or two-parted seeds differ from the corresponding parts of those springing from undivided seeds. The two-lobed seeds produce at first two seed-leaves; a stem grows up that has a woody structure, surrounded by a softer covering or bark, and the leaves are furnished with veins extending in different directions, and presenting a net-like appearance.
10. Such are found in the oak, the maple, the pines, and other fir-trees-in all the common trees of northern forests— and also in the bean, the pea, and the morning-glory. The undivided seeds, on the contrary, produce a single leaf at first; a stem grows up that has a reed-like arrangement, without bark or soft external covering, and the leaves have parallel veins. This kind of vegetable growth may be seen in a palm-stem, a ratan, a corn-stalk, and in different kinds of grain and the grasses.
11. Plants of the first division are what botanists call ex ogenous, or outward-growing, because they grow by additions to their outward surface, while the older and harder portions are the central parts. Those of the second division are called endogenous, or inward-growing, because they grow by internal additions, which constantly push the older and harder portions outward. Thus the outward portion of our forest trees-the sap-wood-is the softest; but the outward portion of the sugar-cane, or of a corn-stalk, is the hardest.
12. Those who have taken this first step in botany will now be able to divide plants, trees, shrubs, and flowering plants generally, into their two leading classes, from the structure10 of their stems, bark, and leaves. They will see that it requires no "mystical lore"11 to give a partial description of a tree, shrub, or herb, from the examination of a single seed. There is no difficulty in understanding this, yet it constitutes one of the most important lessons in botany.
13. Let us then enter, without hesitation, upon this interesting science, that we may gain a knowledge of PLANTS, in respect to their organization,12 their growth, and the properties13 and characteristics14 by which they are classified and distinguished. It is a science in which Solomon delighted; for he wrote about plants, "from the cedar-tree that is in Lebanon, even unto the hyssop that springeth out of the wall."
"The vegetable world, each plant and tree,
14. Botany, moreover, is a science that will create for us a new world of life, teeming15 with ever-varying forms of beauty; it will present strange mysteries in the most common objects around us; and it will unfold16 many lessons of the "wisdom of God in creation." It will furnish us instructive companions wherever we are; and whether we wander by the road-side, in meadows and gardens, or on mountains, it will open to us the great volume of NATURE a volume written "in the only language which has gone forth to the ends of the world, unaffected by the confusion of Babel."
1 ZIG-ZAG, having frequent short turns. 2 UN-CON'-SCIOUS-LY, without knowledge. 3 As'-PECT, appearance.
4 TECH'-NIC-AL, such as belong to some art or profession; not common.
5 €ŎN'-TRAST, different or opposite appear
LOBES, parts; natural divisions.
7 RAT-AN', a species of cane with joints, but without branches.
8 EX-ŎG'-E-NOus, outward-growing.
THE ELEMENTARY PARTS OF PLANTS.-CELL LIFE.
1. ALL plants, from the gigantic cypress-trees of Californis to the microscopic vegetation growing as mould on bread, or mildew on articles of clothing, consist of separate and minute sacs, usually adherent1 together, and called cells. The first thing we can detect, as a seed begins to form in the living plant, is a little cell, much smaller than the point of the finest needle, and visible only by the aid of the microscope. Gradu ally this little cell grows; then it divides into two, or another little cell is added to it; soon more cells are added; and by the time the growing seed is large enough to be seen by the naked eye, it consists of a cluster or mass of these little cells adhering together. (Fig. 2.)
2. After increasing in number for some time in this way, some of these clusters grow into the form of a leaf, and others into the form of a little root. Some, however, have two seed leaves, and some have only one, thus early marking out the two great classes of vegetable growth which we have already described. Thus, in the very seed itself, the germ2 of the future plant lies hidden; even there the giant oak lies wrapped up in its little acorn cradle, a small thing then, yet destined to be not only the monarch of the woods, but the father of mighty forests yet to cover the earth.
3. Such are the wonders-the mighty results-which flow from so small a thing as a single seed. And may it not be that the Almighty formed but one acorn at the time of creation, and that in its little germ—even in its central cell-he folded up-so small that none but Omniscience3 could see i
Fig. 2.-The process of cell growth is here illustrated. shown a highly magnified cell, as first seen by the microscope. minute germ increases by the addition of other cells, until, in 6 and 7, the outlines of a leaf are visible.
At 1 is
-the oak which was to grow from it, and all the acorn seeds which it was to produce; and in those acorn seeds all the vast forests of oak that have since covered the earth? and that in a single grain of wheat he folded up, in miniature,* the myriads of wheat plants which man has gathered in all succeeding harvests?
"Lo! in each seed, within its slender rind,'
5. As cell life is the beginning of the life of plants, even in the seeds, so the entire growth of plants is but a continuation of the same process-consisting of millions upon millions of little cells heaped together-forming alike the massive trunk of the oak, and the finest down upon the tiny leaf. When we consider the exceeding minuteness of these cells in some plants, and that some stems shoot up three or four inch es in a day, we can form some idea of the wonderful rapidity of cell growth. It is supposed that the century plant, a short time before blooming, increases at the rate of over twenty thousand millions of cells in a day!
6. Thus, knowing how all vegetables grow, we can better understand the nature of such curious plants as mould, mildew, and yeast, which, having neither stems nor leaves, consist wholly either of a single cell, or of clusters of little cells adhering together. Yeast, which is put into the dough of bread to make it light, consists of little cell plants so exceedingly small that a cubic inch of yeast is said to contain more than eleven hundred millions of them. As the yeast plant grows rapidly in the dough, spreading all through it, and forming its living cells in countless numbers, it gives off little bubbles of gas, which puff up the dough, and thus "leaven the whole lump."
7. Strange though it may seem, yet all animal growth is the growth of cells also, the same as in vegetables. The
muscles, the bones, the nerves, the hair, the nails, consist of cells. The smallest muscular fibre that the microscope can detect is made up of a row of little cells, much like a string of beads. In shape and mode of growth the animal cells are in all respects like the vegetable; but the substances of which they are composed are different.*
8. In very young plants, and also in the lower grades of vegetable life, such as the mushrooms and the mosses, the walls of the cells are very thin; and these are what are called cellular plants. These cells, when first formed, are eggshaped, or globular, and filled with a liquid substance; but when numbers of them are pressed together in the growing plant they assume various forms, as may be seen by examining thin slices of the pith of different kinds of wood with a microscope. (Fig. 3.)
9. The cells are usually soft; but sometimes they are so filled up and pressed together that they become very hard, as in thorns, prickles, and the shells or coverings of nuts. Potatoes, turnips, and other vegetables are made palatable and digestible by breaking up their cells, containing starch and sugar, in the process of boiling or steaming.
10. Some of the cells, at an early stage of their growth, lengthen into the form of short tubes, and thicken their walls. These form what is called, from their shape, vascular tissue, 16 or woody fibre. Owing to the strength of this tissue, vascular plants grow to a great height, with sufficient firmness to form the ribs of oak that plow the main, or, towering in their native woods like "the mast of some tall admiral," they are
* The cell walls of plants are composed of what is called cel'-lu-lose; but animal cells are composed of an animal element called prō'-te-ine.
At 8, in Fig. 3, is shown a cluster of highly-magnified cells, of globular shape, as first formed. At 9 is a lengthened cell, the beginning of such as are found in vascular tissue At 10 and 11 are globular cells assuming angular forms under the influence of pressure