7. Alnus hirsuta Turczaninow ex Ruprecht, Bull. Cl. Phys.-Math. Acad. Imp. Sci. Saint-Pétersbourg, sér. 2. 15: 376. 1857.
辽东桤木 liao dong qi mu
Alnus hirsuta var. sibirica (Fischer ex Turczaninow) C. K. Schneider; A. incana (Linnaeus) Moench var. glauca Regel; A. incana var. hirsuta Spach; Alnus incana var. sibirica Spach; A. sibirica Fischer ex Turczaninow; A. sibirica var. hirsuta (Turczaninow ex Ruprecht) Koidzumi; A. sibirica var. oxyloba C. K. Schneider; A. sibirica var. paucinervis C. K. Schneider; A. tinctoria Sargent.
Trees to 20 m tall; bark gray-brown, smooth. Branchlets dark gray, angular, densely gray pubescent when young, glabrescent. Buds stipitate, with 2 scales, sparsely pubescent. Petiole 1.5-5.5 cm, densely pubescent; leaf blade suborbicular, rarely broadly ovate, 4-9 × 2.5-9 cm, abaxially light green or glaucescent, densely or sparsely brown hispidulous, rarely subglabrous, sometimes bearded in axils of lateral veins, adaxially dark green, sparsely villous, base rounded or broadly cuneate, rarely cuneate or subcordate, margin undulate-serrate, apex rounded, rarely acute; lateral veins 5-10 on each side of midvein. Female inflorescences 2-8 in a raceme, subglobose or oblong, 1-2 cm; peduncle 2-3 mm; bracts 3-4 mm, woody, base cuneate, apex rounded, 5-lobed. Nutlet broadly ovate, ca. 3 mm, with papery wings ca. 1/4 as wide as nutlet. Fl. May-Jul, fr. Jul-Aug.
Temperate forests, along streambanks; 700-1500 m. Heilongjiang, Jilin, Liaoning, Nei Mongol, Shandong [Japan, Korea, Russia (Siberia)]
The wood is hard and dense, and is used for making agricultural tools and furniture.