Form and size: Medium-sized tree, pyramidal head and coa.r.s.e twigs.
Range: Europe and eastern United States.
Soil and location: Prefers a deep, rich soil.
Enemies: The leaves are the favorite food of caterpillars and are subject to a blight which turns them brown prematurely. The trunk is often attacked by a disease which causes the flow of a slimy substance.
Value for planting: On account of its showy flowers, the horsechestnut is a favorite for the park and lawn.
Commercial value: The wood is not durable and is not used commercially.
Other characters: The _flowers_ appear in large white cl.u.s.ters in May and June. The _fruit_ is large, round, and p.r.i.c.kly.
[Ill.u.s.tration: FIG. 21.--Leaf of the Horsechestnut.]
Comparisons: The _red horsechestnut_ differs from this tree in having red flowers. The _buckeye_ is similar to the horsechestnut, but its bud is not sticky and is of a lighter gray color, while the leaf generally has only five leaflets.
THE WHITE ASH (_Fraxinus americana_)
Distinguishing characters: The terminal *twigs* of glossy olive green color are *flattened* below the bud. Fig. 22. The bud is rusty-brown.
[Ill.u.s.tration: FIG. 22.--Twig of White Ash.]
Leaf: Five to nine leaflets. Fig. 23.
Form and size: A large tree with a straight trunk.
Range: Eastern North America.
Soil and location: Rich, moist soil.
Enemies: In cities it is very often attacked by sucking insects.
Value for planting: The white ash grows rapidly. On account of its insect enemies in cities, it should be used more for forest planting and only occasionally for ornament.
Commercial value: It has a heavy, tough, and strong wood, which is valuable in the manufacture of cooperage stock, agricultural implements, and carriages. It is superior in value to the black ash.
Other characters: The _bark_ is gray. The _flowers_ appear in May.
Comparisons: The white ash is apt to be confused with the _black ash_ (_Fraxinus nigra_), but differs from the latter in having a lighter-colored bud. The bud of the black ash is black. The bark of the white ash is darker in color and the terminal twigs are more flattened than those of the black ash.
[Ill.u.s.tration: FIG. 23.--Leaf of White Ash.]
SUGAR MAPLE (_Acer saccharum_)
Distinguishing characters: The *bud is sharp-pointed*, scaly, and reddish brown. Fig. 24.
[Ill.u.s.tration: FIG. 24.--Twig of the Sugar Maple.]
Leaf: Has sharp points and round sinus. Fig. 25.
Form and size: The crown is oval when the tree is young and round in old age. Fig. 26.
Range: Eastern United States.
Soil and location: Moist and deep soil, and cool, shady positions.
Enemies: Subject to drouth, especially in cities. Is attacked by the _sugar maple borer_ and the _maple phenacoccus_, a sucking insect.
Value for planting: Its rich and yellow color in the fall, and the fine spread of its crown make it a desirable tree for the lawn, especially in the country.
Commercial value: Its wood is hard and takes a good polish; used for interior finish and furniture. The tree is also the source of maple sugar. Fig. 27.
Other characters: The _bark_ is smooth in young trees and in old trees it s.h.a.gs in large plates. The _flowers_ appear in the early part of April.
Other common names: The sugar maple is sometimes called _rock maple_ or _hard maple_.
SILVER MAPLE (_Acer saccharinum_)
Distinguishing characters: The tips of the *twigs curve upwards* (Fig.
28), the bark is scaly, and the leaves are very deeply cleft and are silvery on the under side.
[Ill.u.s.tration: FIG. 25.--Leaf of Sugar Maple.]
Leaf: Deeply cleft and silvery under side. Fig. 29.
Form and size: A large tree with the main branches separating from the trunk a few feet from the ground. The terminal twigs are long, slender, and drooping.
Range: Eastern United States.
Soil and location: Moist places.
Enemies: The _leopard moth_, a wood-boring insect, and the _cottony-maple scale_, a sucking insect.
[Ill.u.s.tration: FIG. 26.--The Sugar Maple.]
Value for planting: Grows too rapidly and is too short-lived to be durable.
Commercial value: Its wood is soft, weak, and little used.
Other characters: The _bark_ is light gray, smooth at first and scaly later on. The scales are free at each end and attached in the center. The _flowers_ appear before the leaves in the latter part of March or early April.
[Ill.u.s.tration: FIG. 27.--Tapping the Sugar Maple.]
Other common names: The silver maple is sometimes known as _soft maple_ or _white maple_.