Description from Flora of China
Trees 3-20 m. Branchlets glabrous, sparsely villous puberulent or tomentose; buds broadly ovoid or conical, brown tomentose, pubescent or glandular hairy. Leaves 12-35 cm; petiole 3-9 cm; axis puberulent or pilose at first, leaflet joint glabrous or densely tomentose; leaflets 3-7(-9); petiolule 2-15 mm; leaflet blade broadly ovate, ovate, to lanceolate or elliptic to obovate-lanceolate, 4-16 × 2-7 cm (terminal much larger), papery to somewhat leathery, glabrous or villous, sometimes villous only along veins abaxially, base blunt or cuneate, margin regularly serrate to crenate-serrate, sometimes entire in lower half, apex acute to long acuminate or caudate; primary veins 5-10 on each side of midrib. Panicles terminal or lateral, 5-10 cm. Flowers dioecious, opening with leaves. Staminate flowers congested; calyx cupular, 1-1.5 mm; corolla absent. Pistillate flowers lax; calyx tubular, 2-3 mm. Samara spatulate to very narrowly so, 2.5-4 cm × 3-7(-15) mm; wing decurrent to middle or lower part of nutlet.
Slopes, along rivers, roadsides, mixed woods; 800-2300 m. Throughout China [Japan, Korea, Russia, Vietnam]