we call decay, they merely return to earth and air again, that succeeding generations of vegetable life may feed upon and be clothed with the same materials. 6. Many are the mysteries in vegetable life that we do not understand. It is, indeed, all a mystery. We can not even tell why plants vary in form, and structure,13 and modes of growth; why some bask in the sunlight, and others court the shade; why those growing in the same soil, and feeding upon the same air and water, put on different colors; why one converts its juices into poison, and another furnishes a delicious and wholesome beverage. Nor has man been enabled to tell how, out of the very same materials, the plant I can form different substances-how out of carbon, hydrogen, and oxygen, it can form woody fibre, and starch, and gum, and sugar, and also an acid that is in all respects like vinegar. 7. Yet all this the plant accomplishes in its chemical laboratory, 14 with a refinement15 of skill far beyond what man possesses. Man can not take the elements and combine them as the plant does; they will not unite at his bidding. Yet the chemical processes which the plant performs must not be regarded as the blind operations of Nature; they are strictly in accordance with definite laws which God has given it; and, while we view the results of these laws with admiration and wonder, we should not forget their origin. 8. But, although man can not do what the plant does, he may aid the plant in performing many of its secret operations; by knowing "how plants grow," he may furnish them food of the right kind, and he may thus cause the landscape to put on a robe of brighter green, the harvests to yield more abundantly, and even the desert and waste places to bud and blossom like the rose. LESSON XIII. THE MYSTERIES OF VEGETATION. 1. We know not why the beech delights the glade1 While in the lower marsh the gourd is found, 3. Why does one climate and one soil endue1 The blushing poppy with a crimson hue, Yet leave the lily pale, and tinge the violet blue'? 4. The twining jasmine', and the blushing rose', 1 GLADE, an opening in a wood. PRIOR. 13 CY-PRESS, an evergreen; the white cedar. 2 CON-IC, tapering upward to a point in the 4 EN-DUE', clothe; supply with. form of a cone. 5 FAN-TAS'-TIE, gay; gaudy. LESSON XIV. PLANTS, THE LUNGS OF CITIES. 1. PUBLIC Squares and spacious streets, well set with trees, have been aptly1 called the lungs of cities. It is certain that the two great organized kingdoms of nature-the animal and vegetable are designed to co-operate2 in their mutual development.3 The beautiful Persian fable, which describes the rose and the nightingale as shut up in a crystal cage, and mutually giving life to each other, though not strictly correct as to the action of the flower, is forcibly illustrative of the relative actions of animal and vegetable life. 2. In modern aquaria1 the theory becomes reality, for aquatic plants keep the water in which they grow in a fit state to sustain animal life. It is a fact well known that fishes do not thrive well in reservoirs destitute of aquatic vegetation. The water of an aquarium need not be changed for weeks or months, if there is a proper proportion of such plants as grow in water. This, then, is the great secret of the aquarium: the plants afford a supply of oxygen to the animals, while the animals supply the plants with the carbon which is indispensable to their growth. 3. So in the atmosphere. In large cities, where carbonic acid gas is produced in large quantities from the lungs of multitudes of people, and from the great number of fires kept constantly burning, trees act as purifiers, by absorbing the carbonic acid which is poisonous to man, and by restoring to the air the life-supporting oxygen. Throughout all portions of the globe this principle is in constant operation, evincing the wisdom and goodness of the Deity in thus beautifully harmonizing the operations of Nature. 1 APT-LY, properly; fitly. 2 CO-OP-ER-ATE, act together. 15 RES-ER-VOIR' (rez-er-vwor'), a place where water is kept in store for fountains, etc. 3 DE-VEL-OP-MENT, growth; progress to 6 IN-DIS-PEN'-SA-BLE, absolutely necessary. higher forms. 7 E-VIN'-CING, showing; making plain. 4 A-QUA'-RI-A (the plural of aquarium), little 8 HÄR'-MO-NI-ZING, causing to agree. ponds, or vessels, for rearing water plants with water animals. LESSON XV. BUDS. 1. A BUD has been called a repetition of the plant on which it grows. It is common to give the name bud to that scaly envelope1 which contains the rudiments of a new plant; but such scales are not required to form a bud, except in cold climates. 2. The first appearance of a young branch or flower is the bud, and a new and independent plant is contained in it, as much as in a seed. Buds not only terminate growing branches, but appear in what are termed axils, or the acute angles formed by the leaves and the stem. From the buds spring branches, which are in all respects like the main stem, and which present an arrangement similar to the leaves. 3. Many buds are never fully developed,3 but seem to have been produced as a resource in case of the destruction of any. Thus, if the terminal5 bud be destroyed, lateral buds, that otherwise would have remained undeveloped, put forth shoots, and the growth of the plant is scarcely checked. It is on this principle that hedges are thickened by trimming off the tops, a process well known to gardeners. 4. Irregular buds often appear in stems gorged' with sap. The rich and much admired grain known as bird's-eye maple is attributed to the numerous buds which have appeared from time to time during the growth of the tree. Frequently two buds appear, side by side, instead of one, owing to an excess of nutritious sap. 5. Thorns are supposed to result from an imperfect growth of what should have been branches or stems. It is well known that many plants, which in a wild state abound in thorns, become free from them by cultivation. In such cases the increased supply of nourishment afforded the plant by better tillage enables the buds to become branches instead of thorns. Thorns are of woody structure, and grow from the branch or stem; while prickles only grow from the bark, and may be peeled off with it, as will appear by stripping the bark from a rose-bush. 6. It should be mentioned here that, as a leaf-bud is really a separate and complete plant in itself—like the parent plant on which it grows-if the leaf-bud can be transferred to another plant, and made to take root in and grow upon it, it will produce a stem having the same qualities as the parent plant from which it was taken. Thus, if a leaf-bud from a greening apple-tree be transferred to another tree, and made to grow upon it, it will produce the same kind of apples as its parent stem. 7. But if the seed of a greening apple be planted, and grow and produce fruit, it will, indeed, bear apples, but it is uncertain what kind of apple; it may be sweet or sour, a russet or a pippin, or perhaps some new kind not before known. It is from seeds alone that new kinds can be produced. But if any particular kind of plant is to be multiplied,10 it can only be done by aid of its leaf-buds—by planting the stems which spring from them, or by the common gardening operations of budding and grafting. 8. It is only plants whose fruit is of a like general character that can be mutually transferred in this way. The buds of the pear, the crab-apple, the common apple, and the quince, can be made to grow each upon the others; but an apple will not grow upon a peach-tree or a cherry-tree. The process of budding and grafting was known and practiced as long ago as the days of Virgil. 9. 11 But various are the ways to change the state In whose moist folds the infant budlet15 grows. |