II. Summer: "In the Tree Tops"
Summer is the leafy season. But the time to begin to study leaves is in the early spring. On nearly all trees the leaf comes as soon as the blossom falls. The first leaves are very small, and they are not green but pink, red, yellow, gray or white. They have been wrapped up in bed clothes all winter. It takes several days of warm sunshine for them to turn green and to grow up. The leaf of the red maple tree, true to its name, is red. On the sugar maple it is a yellow-green, on the silver maple a shining green-white. When they grow to full size these maple leaves all have much the same form. In different members of a plant family there is a resemblance, as in a human family. You can learn to call each one by its "given," as well as by its family name, by looking out for the differences.
When you see a tree with a leaf that would lie in a three to five inch circle, but that is cut down part way into five lobes, you would be safe in thinking that tree a maple. The lobes of the red maple are sharply notched and parted. In the sugar or rock maple, the leaf lobes and partings are more rounded. It is a darker, smoother leaf, too, and grows more thickly on an evenly balanced, round-headed tree. The red maple has straggling branches, and the leaves are thin so light sifts through them, giving the tree an airier look than any other maple.
The leaf of the silver maple is smaller, a sage green above, a cottony white below. It does not sift light, but seems to reflect it like a mirror, as the white underside turns up in every breeze. There are other maples, but these are the best known. The leaves of all-trees and of low plants, too, are alike in being brighter and smoother on the upper side. The underside is paler and rougher, and the veins stand out more plainly. This is because the upper side is a sort of rain and dust coat and sun-umbrella, for the breathing pores underneath. It is the lower side of a leaf that is the most interesting to study under a microscope.
All of the willows have long, slender leaves. Each leaf is a narrow, thin, delicately veined blade that grows by itself, and alternately, along a slender stem, making a sort of feathered branch. The pussy willow leaves are a bright green. The black willow leaf is broader, saw-notched, and it tapers toward both stem and tip
