415. Rhododendron argipeplum I. B. Balfour & R. E. Cooper, Notes Roy. Bot. Gard. Edinburgh. 9: 213. 1916.
毛枝杜鹃 mao zhi du juan
Rhododendron macrosmithii Davidian; R. smithii Nuttall ex Hooker (1859), not R. ×smithii Sweet (1830).
Shrubs or small trees, 2–7.5 m tall; young shoots ca. 4.5 mm in diam. below inflorescence, long-setose. Petiole stout, 10–20 mm, densely glandular-setose; leaf blade leathery, elliptic to oblong-lanceolate, 10.5–12.3 × 3.3–4 cm; base obtuse to rounded; margin reflexed; apex acute, with a sharp point; abaxial surface indumentum continuous, thinly yellowish brown floccose turning whitish later, hairs dendroid; midrib usually with a few bristles at base; adaxial surface moderately bullate, deep green, glabrous; midrib raised abaxially, impressed adaxially; lateral veins 12–17-paired, deeply impressed adaxially. Inflorescence densely umbellate, 10–20-flowered; rachis ca. 5 mm. Pedicel stout, 0.8–1.5 cm, densely glandular-setose; calyx red, fleshy; lobes 5, 5–10 mm, oblong or suborbicular, outside with a few glandular setae; margin glandular-ciliate; corolla
tubular-campanulate, fleshy, deep red, ca. 3.2 × 3.5 cm, with 5 deep red nectar pouches at base, glabrous; lobes 5, rounded, ca. 1 × 1.8 cm, apex emarginate; stamens 8–10, unequal, 1–2 cm; filaments glabrous; anthers obovate, purplish red, 1.8–2 mm; ovary cone-shaped, ca. 4 mm, densely rufous-tomentose and glandular-hairy; style ca. 1.6 cm, glabrous; stigma small, punctiform. Capsule cylindric, straight or slightly curved, ribbed, 20–25 × 4.5–5.5 mm, blackish brown, with vestigial glandular hairs; calyx and style persistent. Fl. May–Jun, fr. Jul–Aug.
Secondary forests on mountain slopes, scrub; 2700–3600 m. S Xizang [Bhutan, NE India, Sikkim].