The bark of the sycamore is a characteristic feature. On the younger trunk and large limbs it is very smooth, greenish-gray in color. The outer bark yearly flakes off in large patches and exposes the nearly white younger bark. Near the base of the old trees the bark becomes thick, dark brown and divided by deep furrows. The flowers are very small and arranged in dense globular green heads.
The leaves are simple, alternate, 4 to 7 inches long and about as broad, light green and smooth above, and paler below. The base of the leafstalk is hollow and in falling off exposes the winter bud. The fruit is a ball about 1 inch in diameter, conspicuous throughout the winter as it hangs on its flexible stem, which is 3 to 5 inches long. During early spring, the fruit ball breaks up, and the small seeds are widely scattered by the wind.
The wood is hard and moderately strong, but decays rapidly in the ground. It is used for butchers’ blocks, tobacco boxes, furniture and interior finish.
The tree grows rapidly, bears transplanting well and is often planted as a shade tree.
The European sycamore or London plane tree, Platanus acerifolia Willd., is less subject to disease than our native species and has been widely planted in this country for ornament and shade. The leaves are more deeply lobed than our sycamore and there are two or three fruit balls on each stem.
WILD CRAB APPLE Malus ioensis Britton
THE wild crab apple, or prairie crab, is found throughout Illinois forming small trees 20 to 30 feet high with trunks from 6 to 12 inches in diameter. In the open it develops a broad open crown with rigid, contorted branches bearing many short, spur-like branchlets, some of which develop into sharp rigid thorns. Under less favorable conditions, these crab apples often form bushy shrubs.