LEAVES OF ALL SHAPES AND SIZES The leaf of the tree is its visiting card. We shall learn to know trees by their leaves, as easily as if the name were written across the face of the leaf. Some leaves have a single blade of green, and for this reason the botanist calls them simple leaves. This blade has a stem that unites it with the twig. A compound leaf is one whose stem bears more than one blade. These small blades are called leaflets. There are two types of compound leaves, one feather-like, having a main stem with leaflets arranged in two rows on opposite sides of this stem. Such a leaf is feather-like. The other type has a leaf stem with all the leaflets attached at one end. The horse chestnut is the best example of this type. The leaves spread from the end of the stalk some what as the fingers rise from the palm of your hand.
The biggest leaves with single blades to be found in our forests grow on trees of the mag nolia family. The silver-lined leaves of the large-leaved cucumber tree are over a foot in length, sometimes two and one-half feet, down South. These great leaves are about one-fourth as wide as long, and at the base each one broad ens and extends backward into two rounded ear like lobes. This gives the tree the name, ear leaved magnolia. The whole leaf flaps in the wind, like the ear of an elephant, and, of course, the wind lashes it into strings and soon robs it of its beauty.
The Northern cucumber tree is another mag nolia whose leaves are tropical-looking. This is the hardiest of the magnolia family, and its heart-shaped leaves are six to ten inches long. They are not large for a magnolia of the South, but they look larger because they grow among the small-leaved trees of the Northern states.
The tulip tree has a large leaf of peculiar form. It is broad like a maple leaf at the base, but at the tip it is cut off square as if with a pair of shears, forming a right angle with its straight sides. Sometimes the leaf is notched, as if a V-shaped piece were cut out of the square tip. These leaves are long-stemmed, their blades polished, and they flutter on the twigs with the lightness of a poplar leaf. Once we have in mind the
form of the leaf of the tulip tree, we shall never forget it, for it is different from all other leaves.
The catalpa tree, which lifts its great blossom clusters above the foliage in late June, is another of the few large-leaved trees of the North. The single blade is heart-shaped, six to eight inches long, and more than half as broad. These leaves usually have plain margins, but sometimes they are wavy and notched near the base so as to produce faint side lobes. The blades hang on long, stout stems.
Among the feather-leaved trees, the walnuts and butternuts, the sumachs, and the ailanthus, furnish examples. A black walnut leaf is often two feet long, with a dozen or more leaflets on the longest ones. These leaflets are always set opposite in pairs, with an odd one on the tip of the leaf stem. Butternut leaves have the same form, but the leaves are longer. They range from fifteen to thirty inches, and have from ten to twenty leaflets, but always an odd number. The peculiar gummy feeling of these hairy leaves, and their pungent butternut odour when bruised, make it easy to know the tree wherever we meet it, through the long summer.
The hickories are cousins of the walnuts, but their leaves, though of the feather form, have larger and fewer leaflets than any walnut tree. A shagbark hickory leaf has one or two pairs of little leaflets on the stem, and above them three of larger size. The pignut has the same habit of clustering its three largest leaves at the tip of the leaf stem, and tapering off at the base with one or two pairs of decreasing size.
The largest of all the compound leaves have branched stems to which leaflets are attached. The main leaf stem's side branches may yet branch again, forming a twice-branched frame work that is set with leaflets, not large, but so numerous as to make the whole leaf surprisingly large. The greatest of these twice-compound leaves is borne by that astonishing, spiny stemmed Hercules' club. A single leaf is often four feet long, and nearly a yard wide. There are no leaflets on the main stem; they are on the side branches.