Part 18

The tree of heaven is useful for landscape planting, succeeding in all kinds of soils and all kinds of growing conditions. It makes a rapid showing and is practically free from all diseases and insect injury.

+SMOOTH SUMAC+ Rhus glabra L.

THE smooth sumac is usually a tall shrub but occasionally it develops as a tree 20 to 25 feet tall with a trunk diameter of 6 to 10 inches. A few large spreading branches form a broad, flat, open head. The twigs are smooth and glabrous and have a thick, light brown pith with small round winter buds.

Twig, one-half natural size. Leaf and fruit, one-fourth natural size.]

The compound leaves are 6 to 18 inches long, composed of 9 to 27 leaflets with sharply notched margins. They are dark green above, whitish beneath, changing to red, purple and yellow early in the autumn.

The flowers are small and green, produced in dense terminal panicles. The fruit is a small globose berry, covered with crimson hairs and has a pleasant acid taste. The conspicuous deep red panicles of fruit remain unchanged on the tree during the winter.

The wood is light and of a golden yellow color. Either as a tree, or as a shrub, the smooth sumac is excellent for ornamental planting, being particularly desirable on terraces or hillsides, where mass effects are desired. It transplants very readily and spreads freely.

The staghorn sumac, Rhus typhina L., is a slightly taller tree, as it reaches a height of 20 to 35 feet, and a stem diameter of 8 to 12 inches. The twigs and leaves are similar to those of the smooth sumac but are conspicuously hairy. Its occurrence is limited to the northern part of the State.

The shining sumac, Rhus copallina L., usually occurs in shrub form but it occasionally reaches a height of 20 feet with a stem diameter of 6 inches. The leaves are smooth above but somewhat hairy beneath with a winged rachis and about 9 to 21 leaflets that are slightly toothed. Late in the summer its foliage turns a brilliant red. The fruit clusters are much smaller than the preceding species. It is found throughout the State.

+SUGAR MAPLE+ Acer saccharum Marsh.

THE sugar maple is an important member of the climax forests which stretch from Maine to Minnesota and southward to Texas and Florida. It is an associate of the hemlocks and the birches in the North, with the beeches and chestnuts through the middle states, with the oaks in the West and with the tulip and the magnolias in the South. In Illinois it is a common and favorite tree throughout the State. In the open it grows fairly rapidly and has a very symmetrical, dense crown, affording heavy shade. It is, therefore, quite extensively planted as a shade tree. The bark on young trees is light gray and brown and rather smooth, but as the tree grows older, it breaks up into long, irregular plates or scales, which vary from light gray to almost black. The twigs are smooth and reddish-brown, and the winter buds are smooth and sharp-pointed. The tree attains a height of more than 100 feet and a diameter of 3 feet or more. The sap yields maple sugar and maple syrup.

Leaf, one-third natural size.

Twig, one-half natural size.]

The leaves are 3 to 5 inches across, simple, opposite, with 3 to 5 pointed and sparsely-toothed lobes, the divisions between the lobes being rounded. The leaves are dark green on the upper surface, lighter green beneath, turning in autumn to brilliant shades of dark red, scarlet, orange and clear yellow.

The flowers are yellowish-green, on long threadlike stalks, appearing with the leaves, the two kinds in separate clusters. The fruit, which ripens in the fall, consists of a two-winged "samara", or "key", the two wings nearly parallel, each about 1 inch in length and containing a seed. It is easily carried by the wind.

The wood is hard, heavy, strong, close-grained and light brown in color. It is known, commercially as hard maple, and is used in the manufacture of flooring, furniture, shoe-lasts and a great variety of novelties.

The black maple, Acer nigrum Michx., occurs with the sugar maple with darker bark. The leaves are usually wider than long, yellow-green and downy beneath, and the base of the petioles enlarged. The two lower lobes are very small; the lobes are undulate or entire.

+SILVER MAPLE+ Acer saccharinum L.

THE silver or river maple, also called the soft maple, occurs on moist land and along streams. It attains heights of 100 feet or more and diameters of 3 feet or over. It usually has a short trunk which divides into a number of large ascending limbs. These again subdivide, and the branches droop but turn upward at the tips. The bark on the old stems is dark gray and broken into long flakes or scales; on the young shoots it is smooth and varies in color from reddish to a yellowish-gray. The silver maple grows rapidly and has been much planted as a shade tree. Because of the brittleness of its wood, it is often damaged by summer storms and winter sleet.

Twig, one-half natural size. Leaf, one-third natural size.]

The leaves are opposite on the stem, have from 3 to 5 lobes ending in long points with toothed edges and are separated by deep angular sinuses or openings; they are pale green on the upper surface and silvery-white underneath. The buds are rounded, red or reddish-brown, blunt-pointed; generally like those of red maple.

The flowers appear in the spring before the leaves, in dense clusters, and are of a greenish-yellow color. The fruit ripens in late spring. It consists of a pair of winged seeds or "keys" with wings 1 to 2 inches long on slender, flexible, threadlike stems about an inch long.

The wood is soft, weak, even-textured, rather brittle, easily worked, and decays readily when exposed. It is considerably used for boxboards, furniture, veneers and fuel.

The red maple, or swamp maple, Acer rubrum L., has leaves deeply lobed with the lobes sharply toothed. The autumn color is deep red. The flowers also are red and the fruit is small reddish, maturing late in spring.

+BOX ELDER+ Acer negundo L.

THE box elder is a fairly rapidly growing tree, found commonly along streams rather generally over the State. It is a tree of medium size, rarely reaching over 24 inches in diameter and 60 to 70 feet in height. It has been considerably planted for shade because in good soil its growth is rapid. Its limbs and branches, however, are fragile, and the tree as a whole is rather subject to disease. It is not long-lived or generally satisfactory for any purpose. It is prolific in reproduction but is largely destroyed by grazing and cultivation.

Twig, two-thirds natural size. Leaf, one-third natural size.]

The bark on young branches is smooth and green to purple in color; on old trees it is thin, grayish to light brown and deeply divided.