FRUIT.—October; 1-celled, 1-seeded samaras, spirally twisted, reddish or yellow-green, borne in crowded clusters.
WINTER-BUDS.—Terminal bud absent; lateral buds about 1/8 inch long, subglobose, brownish, downy.
BARK.—Twigs yellowish to red-brown, velvety-downy; thin, grayish and shallowly fissured on old trunks.
WOOD.—Soft, weak, of coarse and open grain, pale yellow, satiny, with thick, lighter colored sapwood.
NOTES.—A native of China, but naturalized in the United States and planted frequently in southern Michigan as a foliage tree. Only the pistillate trees should be planted, as these are almost free from the objectionable odor of the staminate trees. The smoke and dust of our large cities have little effect on the foliage, and the trees are perfectly hardy in the southern part of the state.
ACERACEAE
SUMMER KEY TO THE SPECIES OF ACER
| a. | Leaves simple; twigs usually without whitish bloom. | |||||
| b. | Leaf-sinuses acute at the base. | |||||
| c. | Leaf-lobes long and narrow, the sides of the terminallobe diverging; leaves silvery white beneath; twigsrank-smelling when broken. | A. saccharinum, p. [185]. | ||||
| cc. | Leaf-lobes short and broad, the sides of the terminallobe converging; leaves not conspicuously white beneath;twigs not rank-smelling when broken. | |||||
| d. | Leaves 2-4 inches broad, thin, not pentagonally 5-lobed;wings of fruit 3/4-1 inch long. | |||||
| e. | Leaves distinctly white-downy beneath; twigs appressed-hairy,at least near the tip; fruit hanging inpendulous racemes, persistent on the tree untilautumn; seed portion with pit-like depression onone side; usually a shrub or bushy tree. | A. spicatum, p. [179]. | ||||
| ee. | Leaves not distinctly white-downy beneath; twigsglabrous; fruit hanging in clusters, falling in earlysummer; seed portion without pit-like depressionon one side; medium-sized tree. | A. rubrum, p. [187]. | ||||
| dd. | Leaves 4-7 inches broad, thick, pentagonally 5-lobed;wings of fruit 1-1/2 inches long. | A. pseudo-platanus, p. [191]. | ||||
| bb. | Leaf-sinuses rounded at the base. | |||||
| c. | Lower sides of leaves and petioles distinctly downy, thelobes undulate or entire; leaves very thick, drooping atthe sides. | A. saccharum nigrum, p. [183]. | ||||
| cc. | Lower sides of leaves and petioles essentially glabrous,the lobes serrate; leaves not thick, not drooping at thesides. | |||||
| d. | Leaves coarsely and sparsely toothed or notched;bark not longitudinally white-striped; large trees. | |||||
| e. | Twigs coarse; petioles exuding a milky juice whencut; wings of fruit diverging by nearly 180°; barkof the trunk closely fissured, not scaly. | A. platanoides, p. [189]. | ||||
| ee. | Twigs slender; petioles not exuding a milky juicewhen cut; wings of fruit diverging only slightly;bark of the trunk deeply furrowed, often cleavingin long, thick plates. | A. saccharum, p. [181]. | ||||
| dd. | Leaves finely and abundantly toothed; bark longitudinallywhite-striped; a bushy tree or shrub. | |||||
| aa. | Leaves compound; twigs usually with whitish bloom. | A. negundo, p. [193]. | ||||