notched, and are therefore characteristic oak leaves, while those of the chestnut-oak are not so, because almost all oaks have leaves more or less scalloped or deeply indented. 7. Great as is the variety in the shapes of oak leaves, any one of them would almost surely be at once recognized as belonging to an oak-tree by its peculiar scallopings. But suppose a person had never seen or heard of a chestnutoak leaf, would he be likely to recognize such a leaf simply by its outline ? There is still another oak with simple leaves; and they are not even toothed, but entirely smooth all around the edge. Looking at that tree, which is called the willow-oak, scarcely any one would suppose it to be an oak unless he could see its flowers or its fruit, the acorns. 8. This fact brings us to consider a very important point in the study of a plant. It is not the leaf which tells us what kind of plant it is: it is the flower and the fruit. Whatever be the shape of the leaf, if the plant bears acorns it is an oak. If a tree has cherries and cherry blossoms, it is a cherry. 9. It is true that, in many families of plants, leaves by their shape alone announce at once the kind of plant to which they belong; at the same time there is a large number of plants that cannot be known by their leaves, but only by their flowers and fruits. It is by flowers and fruits that plants are classified; and the more nearly alike they are in two plants, the more closely are those plants related. The flower and the fruit proclaim the nature of the plant. tree is known by its fruit." “A 15.-SHAPES OF LEAVES. PART II. ap-prox'i-măt-ing, coming near to. dig'i-tate, having several leaflets, arranged like the fingers of the hand, at the extremity of a stem. pin'nate, shaped like a feather. struct'ure, make, construction. es-sen'tial, belonging to the inner ten'dril, a thread-like spiral shoot of a nature of an object. mam'mal, an animal the female of which suckles its young. plant that winds round another body for support. ter'min-al, relating to the extremity. 1. ALTHOUGH the flower and its fruit tell us what the plant is, and leaves do not with any certainty, there is yet a strong similarity, as well in texture as in shape, in the leaves of most of the plants comprised within any one family. Especially in texture is this marked similarity observable; and perhaps in most cases the peculiar structure of the leaf, aside from its shape, is indicative of the order to which the plant belongs. The leaves of the grasses are very much alike; so are the leaves of the sedges;-and though it is true, also, that in some instances a sedge-leaf might be mistaken for a grass-leaf, it must be remembered that the sedge family and the grass family have some points of similarity. 2. Again, if we should come upon a plant belonging to the common potato or nightshade family, we would be almost sure to recognize the family resemblance at the very first glance, provided we were already familiar with a number of plants included in that order. Yet the leaves of the nightshade family vary considerably in shape, and it is therefore decisively the texture and peculiar appearance of the leaves that announce the kinship of the plant. And thus we are led back to the consideration of the willowoak and chestnut-oak leaves, which, entirely unlike the typical oak leaf in shape, are yet very much like all other oak leaves in texture and other essential structure. 3. Still more widely divided than oak leaves are such as are called pinnate, in which the separated parts are actually distinct leaflets, some even provided with stalks. Such compound leaves may be seen in almost every garden by looking at a rose-bush. In the cut we see what appear LEAF OF THE ROSE. to be five distinct leaves attached to one twig; but the fact is that they are only leaflets, and, together with the stalk which bears them all, constitute one complete leaf. Each of these leaflets has a short stalk, which connects it with the main stem passing between the pairs, and having an odd one at the end. A rose-bush may have leaves of seven or nine leaflets. 4. Among our forest trees, hickory, walnut, butternut, locust, and ash have pinnate leaves; and on the honeylocust not only are the leaves pinnate, but on the same tree may also be found leaves doubly pinnate, and even tripinnate. The same may be seen in the pea-vine, which is simply pinnate; but here the place of the absent terminal leaflet is supplied by a tendril. 5. But if we examine a bean-plant, we do find an odd leaf, together with a pair of leaflets; that is, each leaf is composed of three leaflets. The many varieties of beanplants are all thus three-leaved. Besides, the woods are full of three-leaved plants belonging to other kinds of the bean or pulse order of plants. In addition to these and some others, we must not overlook a most extraordinary three-leaved plant, plentiful in almost every forest and on almost every stone-fence in the country; only too well known by persons who have been poisoned by it, and yet not so well known by most people as it ought to be, for it is often confounded with a plant having digitate leaves. 6. Here, side by side, the forms of the two leaves can be compared. On the left is the digitate leaf of the beautiful Virginia creeper, entirely harmless; on the right is the pinnate leaf of the poison-vine. The innocent plant is five-leaved; the noxious plant is three-leaved. But we LEAF OF VIRGINIA CREEPER. LEAF OF POISON-VINE. should also notice particularly that the arrangement of the leaflets is quite different in the two plants. In the poisonvine we see a pair of leaflets and a terminal odd one; whereas in the Virginia creeper there is no pairing of leaflets whatever, but the five parts radiate from a center. All the leaflets come out together from one point at the tip of the leaf-stalk. 7. Plants there are with digitate leaves, having three, five, seven, nine, or more leaflets. Clover has digitate LEAFLET OF WOOD-SORREL leaves of three leaflets, while the leaves of the buck-eye and horse-chestnut have five, seven, and nine leaflets. The pretty little wood-sorrel plant of small yellow flowers has three most beautiful, inverted, heart-shaped leaflets, radiating from the tip of the little leaf-stalk. 8. In leaves like those of the maple we see the main veins radiating from a point at the top MAPLE LEAF. of the stalk. Such leaves are therefore much like the digitate kind, only they are not completely divided into separate leaflets. Sassafras leaves offer forms somewhat different. On the same tree may be seen oval, two-lobed, and threelobed leaves. Thus on one and the same plant we see leaves strikingly different in form; yet the texture, the color, and the veining are exactly after the same pattern in them all, so that a sassafras leaf, whether oval or cleft, can at once be easily known. 9. Recalling to mind the leaf of the apple, buckwheat, morning-glory, oak, rose, Virginia creeper, maple, and sassafras, we have pretty good models after which nearly all leaves are built, approximating to one or the other, with certain variations peculiar to the species. 10. Another important matter regarding the leaves of plants is their relative position on the stems. There are two principal and very marked arrangements of leaves. Leaves are either opposite one to another on the stem, or they are alternate, or not opposite. There are whole orders of plants with none but opposite leaves, as the mint family. In other orders the leaves of every plant are alternate. And again, in some orders, and even on the same plants, |