Gustavus Frankenstein.

FIRST READING.

By far the greater number of plants have leaves of an oval shape, and we have only to go through our forests and gardens to see them on every hand. Exceedingly varied are they indeed, from very narrow to very broad oval, some with toothed, some with smooth edges, and some even deeply notched; and yet to such an extent does this tendency toward a rounded form prevail, that there seems scarcely a plant in whose leaves a trace of the oval may not be found.

The apple tree gives us a good specimen of an oval leaf; and an immense number of plants have leaves resembling it in shape. In many plants, the leaves are almost the very counterpart of those of the apple-tree; in some, they are narrower, and in others, still narrower, till we come to very slender blades like those of the grasses; and then, beyond still, to the needle-like leaves of the pines. On the other hand, plants are to be found with leaves broader than the apple-leaf; and so on, rounder and rounder, until we come to such plants as the nasturtium and the water-lily, whose leaves are almost as round as circles.

There are certainly to be met with most remarkable departures from the oval shape, and we need but refer to such leaves as those of the buckwheat, to find that roundness seems to be entirely absent.

This style of leaf, of which there are many variations, is apparently built on the model of the heart-shaped leaf, of which the morning-glory affords a familiar example. It will be noted, however, that instead of the curvilinear flow of outline, in which a tendency to oval roundness is plainly visible, the hastate leaf of the buckwheat is angular throughout.

Another marked characteristic of most leaves is, that they terminate in a point, either sharp to extreme slenderness, or blunt to broad roundness; for even in a circular leaf there is one point which is its extremity, and to which the margin from either side approaches by a convexity. To this pointedness of leaves the exceptions are exceedingly rare. A plant found in some parts of our own country—the magnificent tulip-tree—presents, perhaps, the most extraordinary of all.

Now this leaf comes out of a bud-case which is actually oval. The young leaf is folded double inside of its bud-case; and, besides, its small stalk is bent over so as to bring the little leaf to hold its end downwards. We can see this curious arrangement very well, just after the bud has opened, and the young leaf has come out. However, it soon straightens up, holds its little head aloft, and looks like a pretty little flag. After this it spreads apart into the full leaf, and stands up like a banner. If the bud be held up to the light, the young leaf can be seen nicely folded up inside, with its head snugly bent down. There is nothing prettier, or more curious, to be seen in the woods, than the young buds of the tulip-trees, when they are about to open, or after they have unfurled their little flags; and all summer long, even from earliest spring, the tulip-trees are continually unfolding their buds.

There are leaves broader above than below, and some, instead of ending in a point, have a notch or indentation of some sort. Oak-trees give us many fine and varied samples of notched and lobed leaves. And yet the leaf of the chestnut-oak is not at all notched, being simply ovate, pointed, and toothed. The leaves of the bur and the pin oaks, on the contrary, are lobed and 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.

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 chestnut-oak 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 anyone would suppose it to be an oak unless he could see its flowers or its fruit, the acorns.

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.

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 these are in two plants, the more closely are those plants related. The flower and the fruit proclaim the nature of the plant. “A tree is known by its fruit.”