29. Betula humilis Schrank, Bayer. Fl. 1: 420. 1789.
甸生桦 dian sheng hua
Betula humilis var. vulgaris Perfiljev; B. sibirica Watson.
Shrubs to 2 m tall; bark dark brown. Branches black-brown, glabrous, densely resinous glandular; branchlets brown, densely pubescent and yellow resinous glandular. Petiole ca. 5 mm, pubescent; leaf blade ovate, broadly ovate, or ovate-elliptic, 1-2.5(-4) × 0.6-1.5(-2) cm, both surfaces glabrous, base broadly cuneate or cuneate, rarely subrounded, margin irregularly and doubly coarsely serrate, apex acute; lateral veins 4 or 5 on each side of midvein. Female inflorescence erect, oblong, 1-1.5 cm × 4-6 mm; peduncle 1-3 mm, sparsely pubescent and resinous glandular; bracts 3-4 mm, ciliate, 3-lobed, middle lobe oblong, lateral lobes spreading, ovate or oblong, ca. 1/2 as long as or subequal to middle lobe. Nutlet oblong, ca. 2 × 1.5 mm, with membranous wings ca. 1/2 as wide as nutlet. Fl. Jun-Jul, fr. Jul-Aug. 2n = 28.
Swamps and meadows in forests, 1400-1800 m. Xinjiang (Altay Shan) [Kazakhstan, N Mongolia, Russia (Siberia); Europe]
A. K. Skvortsov believes that this species is a synonym of Betula fruticosa.