Acer barbinerve Maxim. ex Miq.

Shrubs or small, multistemmed trees, to 7 m tall, dioecious. Bark grayish yellow or grayish brown, smooth. Young branchlets puberulent, becoming nearly glabrous and dull reddish brown in second year; bud scales 2 pairs. Leaves deciduous; petiole 4-6 cm, slender, puberulent when young, glabrescent; leaf blade suborbicular or ovate, 8-10 × 6-8 cm, membranous, abaxially hirsute-pubescent especially on veins, adaxially glabrous, primary veins 5, base cordate or subcordate, margin doubly serrate with coarse obtuse teeth, 5-lobed, rarely 7-lobed; middle and lateral lobes acuminate apically; basal lobes acute. Inflorescence racemose, lateral from leafless buds. Pedicel 1-2 cm, slender, glabrous. Staminate racemes very short, ca. 1.5 cm, 5- or 6-flowered; sepals 4, oblong, slightly ciliate along margin, ca. 5 mm; petals 4, rhombic-obovate, slightly shorter than sepals; stamens 4, ca. as long as sepals, glabrous, absent in pistillate flowers; disk 4-lobed, glabrous, intrastaminal; ovary absent or very rudimentary in staminate flowers. Pistillate racemes with slender peduncle ca. 4 cm, puberulent, usually 7-flowered; sepals oblong, ca. 4.5 mm, ciliate, with long hairs at apex; petals obovate, nearly as long as sepals, distinctly clawed; ovary glabrous; style ca. 2 mm, glabrous; stigmas revolute. Infructescence pendulous, racemose, ca. 5 cm. Samaras 5-7; nutlets subglobose, ca. 10 × 8 mm, rugose, strongly veined; wing introrsely falcate, slightly contracted at base, including nutlet 3-3.5 cm, wings spreading obtusely. Fl. Apr, fr. Aug-Sep. 2n = 26.

Heilongjiang, Jilin, Liaoning [N Korea, E Russia].

Mixed and coniferous alpine forests; 500-2300 m.

Acer barbinerve var. chanbaischanense S. L. Tung; A. diabolicum Blume ex Koch subsp. barbinerve (Maximowicz ex Miquel) Wesmael.