186. Rhododendron mekongense Franchet, J. Bot. (Morot). 12: 263. 1898.
弯月杜鹃 wan yue du juan
Shrubs, deciduous, semievergreen or evergreen, (0.6–)1–1.5(–2) m tall; young growth scaly, long-setose; bud scales deciduous. Petiole 1–2(–5) mm, sparsely scaly, long-setose; leaf blade leathery, obovate or oblanceolate to obovate-elliptic, 2.5–5(–6.5) × 0.8–2(–2.7) cm; base cuneate; margin usually setose; apex rounded, mucronate; abaxial surface slightly glaucous, scales 1–4 × their own diameter apart, unequal, pale or dark brown; midrib usually sparsely setose; adaxial surface dark green, without scales, glabrous or long-setose. Inflorescence 2–4(–5)-flowered. Pedicel 1–2.5 cm, scaly, usually sparsely long-setose; calyx lobes rounded, ovate, oblong to lanceolate, persistent in fruit, scaly, long-ciliate or glabrous; corolla broadly campanulate, yellow, greenish yellow, or creamy yellow, sometimes lined and flushed rose on outside, 1.5–2(–2.3) cm; tube 7–11 mm; outer surface usually scaly; stamens 10, filaments villous or pubescent towards base; ovary scaly; style thick, sharply bent. Capsule cylindric, 7–11 mm, densely scaly. Fl. May–Jun, fr. Jul–Sep.
Forest margins, thickets, scrub, open pastures, slopes, valleys, cliffs, rocks, rarely swamps; 3000–4300 m. S Xizang, NW Yunnan [India, NE Myanmar, Nepal].