岩桦 yan hua

Betula delavayi Franchet var. calcicola W. W. Smith, Notes Roy. Bot. Gard. Edinburgh 8: 333. 1915; B. forrestii (W. W. Smith) Handel-Mazzetti var. calcicola (W. W. Smith) Handel-Mazzetti.

Shrubs to 4 m tall; bark gray-black. Branches erect or prostrate; branchlets grayish brown, densely white or yellow villous. Petiole 1-2 mm, densely yellow sericeous-villous; leaf blade suborbicular or broadly ovate, rarely oblong, 2-3.2 × 1.5-2.5 cm, leathery, abaxially densely yellow sericeous-villous along veins, sparsely resinous punctate, adaxially densely white or yellow sericeous-villous, base rounded or broadly cuneate, margin obtusely doubly serrate, apex rounded or obtuse; lateral veins 9-16 on each side of midvein, distinctly raised abaxially, deeply impressed adaxially. Female inflorescence oblong-cylindric, 1.5-2 cm × 7-10 mm; peduncle ca. 2 mm; bracts ca. 5 mm, densely sericeous-villous, base hispidulous, margin densely and long ciliate, middle lobe oblong, lateral lobes ovate, 1/3-1/2 as long as middle lobe. Nutlet suborbicular, ca. 2.5 × 2 mm, with very narrow wings. Fl. Jun-Jul, fr. Jul-Aug.

* Thickets on cliffs; 2800-3800 m. SW Sichuan, NW Yunnan