黑榆 hei yu

Trees or shrubs, to 15 m tall, d.b.h. to 30 cm, deciduous. Bark longitudinally fissured. Branchlets pubescent when young, glabrescent or ± pubescent, sometimes with irregularly longitudinally fissured corky layer. Winter buds ovoid; bud scales partly pubescent. Petiole 5-10(-17) mm, pubescent; leaf blade obovate to obovate-elliptic, 4-9(-10) × 1.5-4(-5.5) cm, abaxially densely pubescent when young but glabrescent with tufted hairs only in axil of veins, adaxially sparsely hirsute when young but glabrescent, base oblique, margin doubly serrate, apex caudate-acuminate to acuminate; secondary veins 12-22 on each side of midvein. Inflorescences fascicled cymes on second year branchlets. Perianth glabrous, 4-lobed. Samaras tan, obovate to ± obovate, 1-1.9 × 0.7-1.4 cm; stalk pubescent, ca. 2 mm; wings usually glabrous. Seed toward apex and in center of samara.

Slopes, wetlands near streams, valleys; below 2300 m. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Jilin, Liaoning, Nei Mongol, Ningxia, E Qinghai, Shaanxi, Shandong, Shanxi, Zhejiang [Japan, Korea, Mongolia, Russia (Far East, E Siberia)].