Description from Flora of China
Rhododendron colletum I. B. Balfour & Forrest; R. emaculatum I. B. Balfour & Forrest.
Shrubs or small trees, 2–9 m tall; branchlets stout, initially floccose, later glabrescent. Petiole narrowly winged, 15–30 mm, sparsely floccose or glabrous; leaf blade leathery, oblanceolate to oblong-lanceolate, 10–25 × 3–7 cm; base attenuated, narrow to subrounded; apex acuminate; abaxial surface fawn to pale cinnamon, indumentum thin, 1-layered, compacted, hairs radiate; adaxial surface deep green, glabrous. Inflorescence racemose-umbellate, 10–25-flowered; rachis stout, ca. 25 mm, puberulent. Pedicel 1.5–2.5 cm, sparsely pubescent or glabrescent; calyx lobes 5, 1–2 mm, broadly triangular, glabrous; corolla broadly campanulate, white flushed pink to pink, inner surface with or without few crimson spots on tube on upper lobes, with basal blotch, 4–5 × 4.5–5.5 cm, lobes 5; stamens 10, unequal, filaments pubescent at base; ovary ca. 8 × 3 mm, densely pale brown-tomentose; style slightly curved, glabrous, stigma shallowly lobed. Capsule oblong-cylindric, slightly curved, 20–40 × 4–8 mm, hairy. Fl. May–Jun, fr. Sep–Nov.
Coniferous forests, Rhododendron thickets, mountains; (2700–) 3200–4500 m. SW Sichuan, SE Xizang, NW Yunnan [NE Myanmar].