466. Rhododendron leptothrium I. B. Balfour & Forrest, Notes Roy. Bot. Gard. Edinburgh. 11: 84. 1919.
薄叶马银花 bao ye ma yin hua
Rhododendron australe I. B. Balfour & Forrest.
Shrubs or small trees, 3–4(–6) m tall; young shoots densely white-pubescent. Petiole 10–18 mm, densely pubescent or sparsely glandular-hairy; leaf blade subleathery, lanceolate or oblong-lanceolate, 4–12 × 1.8–3.5 cm; base cuneate; margin shallowly undulate, slightly revolute, tapering toward truncate apex; adaxial surface pubescent only on midrib; midrib and lateral veins prominent on both surfaces. Inflorescences subapical, usually in clusters of 2–4, 1-flowered. Pedicel 1.5–2.5 cm, densely shortly glandular-setose; calyx lobes large, elliptic or oblong-ovate, 6–8 mm, glandular hairy at base on outer surface; margin glabrous or glandular-ciliate, apex obtuse; corolla rotate, pale rose to magenta-purple, with dark flecks on upper lobes, tube shorter than lobes; lobes obovate, 2–2.5 cm; stamens 5, unequal, shorter than corolla, filaments flat, pubescent below the middle; ovary ovoid, ca. 3 mm, apex glandular hairy; style ca. 2.2 cm, longer than stamens, exserted, glabrous. Capsule ovoid, ca. 6 mm, glandular and glandular-setose, surrounded by persistent calyx lobes. Fl. May–Jun, fr. Sep–Nov.
Thickets; 1700–3200 m. SW Sichuan, SE Xizang, W Yunnan [Myanmar].