A small, deciduous tree 15 to 20 ft high, or a shrub; young shoots glabrous; winter buds stalked. Leaves 2 to 4 in. long and wide, deeply five-lobed, heart-shaped at the base, margins sharply double-toothed, bright green and glabrous above, paler beneath, with reddish hairs along the main veins when young, reduced to their axils when mature; lobes triangular, long-pointed; leaf-stalk half as long as the blade. Flowers on glabrous, short stalks, produced along with the leaves, eight to ten, in racemes. Fruits pale brown; keys 1 to 11⁄4 in. long; wings 2⁄5 in. wide, incurved, and spreading at a wide angle.
Native of Japan, where it grows in sub-alpine forests in the northern part of the main island and in Hokkaido. The dying leaves turn a beautiful canary yellow. It is allied to A. micranthum (q.v. for the marks of difference). Introduced in 1902.
var. rubripes Komar. – A native of N. Korea and N. China, differing from the type in the longer, more tapered lobes, the reddish leaf-stalks and young growth, and the more spreading wings of the fruit.