RED MAPLE (_Acer rubrum_)
[Ill.u.s.tration: FIG. 28.--Terminal Twig of Silver Maple.]
Distinguishing characters: The *bark is smooth and light gray*, like that of the beech, on the upper branches in older trees, and in young trees over the whole trunk. Fig. 30. The buds are in cl.u.s.ters, and the terminal twigs, Fig. 31, are quite red.
[Ill.u.s.tration: FIG. 29.--Leaf of the Silver Maple.]
Leaf: Whitish underneath with three-pointed lobes. Fig. 32.
Form and size: A medium-sized tree with a narrow, round head.
Range: Eastern North America.
Soil and location: Prefers moist places.
Enemies: Leaf blotches (_Rhytisma acerinum_) which, however, are not very injurious.
Value for planting: Suitable as a shade tree for suburban streets. Its rich red leaves in the fall make it attractive for the lawn.
[Ill.u.s.tration: FIG. 30.--Bark of the Red Maple.]
Commercial value: Its wood is heavy, close-grained, and takes a good polish. Used for furniture and fuel.
Other characters: The _bud_ is small, round, and red. The _flowers_ appear before the leaves are out in the early part of April.
[Ill.u.s.tration: FIG. 31.--Twig of the Red Maple.]
[Ill.u.s.tration: FIG. 32.--Leaf of the Red Maple.]
Other common names: The red maple is sometimes known as _swamp maple_.
[Ill.u.s.tration: FIG. 33.--Twig of Norway Maple.]
Comparisons: The red maple is apt to be confused with the silver maple, but the latter can be distinguished by its turned-up twigs and scaly bark over the whole trunk of the tree, which presents a sharp contrast to the straight twig and smooth bark of the red maple. The latter has a bark similar to the beech, but its branches are _opposite_, while those of the beech are _alternate_.
NORWAY MAPLE (_Acer platanoides_)
Distinguishing characters: The bud, Fig. 33, is *oval and reddish-brown*
in color; when taken off, a *milky juice exudes*. The bark is close.
Fig. 34
[Ill.u.s.tration: FIG. 34.--Bark of Norway Maple.]
Leaf: Like the leaf of the sugar maple but thicker in texture and darker in color. Fig. 35.
Form and size: A tall tree with a broad, round head.
Range: Europe and the United States.
Soil and location: Will grow in poor soil.
Enemies: Very few.
Value for planting: One of the best shade trees.
Commercial value: None.
Other characters: The _bark_ is close like that of the mockernut hickory.
Comparisons: The Norway maple is apt to be confused with the _sycamore maple_ (_Acer pseudoplata.n.u.s_), but differs from the latter in having a reddish bud instead of a green bud, and a close bark instead of a scaly bark.
BOX ELDER (_Acer negundo_)
Distinguishing characters: The terminal *twigs are green*, and the buds are round and small. Fig. 36.
Leaf: Has three to seven leaflets.
[Ill.u.s.tration: FIG. 35.--Leaf of Norway Maple.]
Form and size: A medium-sized tree with a short trunk and wide-spreading top.
Range: Eastern United States to the Rocky Mountains.
Soil and location: Grows rapidly in deep, moist soil and river valleys, but accommodates itself to the dry and poor soil conditions of the city.
[Ill.u.s.tration: Figure 36.--Twig of the Box Elder.]
Enemies: Few.
Value for planting: Used as a shade tree in the Middle West, but the tree is so ill formed and so short-lived that it is not to be recommended.
Commercial value: None. The wood is soft.
Other characters: The _bark_ of the trunk is smooth and yellowish-green in young trees and grayish brown in older specimens. The _flowers_ appear in the early part of April. The _fruit_ takes the form of yellowish-green keys which hang on the tree till late fall.
Other common names: The box elder is also commonly known as the _ash-leaf maple_.
GROUP VI. TREES TOLD BY THEIR FORM: ELM, POPLAR, GINGKO AND WILLOW
How to tell them from other trees: The trees described in this group are so distinctive in their general _form_ that they may, for the purpose of study, be grouped together, and distinguished from all other trees by this characteristic.
How to tell them from each other: The American elm is _vase-like_ in shape; the Lombardy poplar is narrow and _spire-like_; the gingko, or maidenhair tree, is _odd_ in its mode of _branching_; and the weeping willow is extremely _pendulous_.