油桦 you hua

Betula fruticosa Pallas var. ruprechtiana Trautvetter; B. humilis Schrank var. ovalifolia Regel; B. humilis var. reticulata Regel; B. humilis var. ruprechtii Regel; B. reticulata Ruprecht.

Shrubs to 2 m tall; bark gray-brown. Branches dark brown, sparsely pubescent and resinous glandular; branchlets brown, densely yellow villous and pubescent, ± resinous glandular. Petiole 3-7 mm; leaf blade elliptic, ovate-elliptic, rhombic-elliptic, rhombic-ovate, or obovate, 3-3.5 × 2-4 cm, both surfaces densely resinous glandular and white villous when young, abaxially glabrous, base broadly cuneate, cuneate, or subrounded, margin simply minutely serrate, apex acute or obtuse; lateral veins 5-7 on each side of midvein. Female inflorescence erect, oblong, rarely globose, 1.5-3 cm × 7-12 mm; peduncle 2-6 mm, sparsely pubescent; bracts 5-6 mm, ciliate, 3-lobed, middle lobe oblong, lateral lobes erect or subspreading, oblong or ovate, slightly shorter than middle lobe. Nutlet elliptic, ca. 3 × 1.5 mm, with membranous wings 1/3-1/2 as wide as nutlet. Fl. Jun-Jul, fr. Jul-Aug.

Peat bogs, marshes, moist places; 500-1200 m. S Heilongjiang, Jilin (Changbai Shan), Nei Mongol [Japan, Korea, Russia (Far East)]