Description from Flora of China
Rhododendron mairei H. Léveillé.
Shrubs or small trees, 2–8 m tall; leaf scars conspicuous; branchlets stout, glabrous. Petiole 20–30 mm, floccose, glabrescent; leaf blade thickly leathery, broadly elliptic to obovate-elliptic, 8–17 × 6–8 cm; base rounded to subcordate; margin somewhat undulate; apex obtuse and apiculate; abaxial surface fawn to gray-tawny, indumentum thin, 1-layered, compacted, hairs radiate; adaxial surface green, glabrous. Inflorescence racemose-umbellate, 15–30-flowered; rachis 20–30 mm, sparsely floccose. Pedicel 2–3 cm, floccose, glabrescent; calyx lobes 5, 1–1.5 mm, triangular, sparsely puberulent outside, margin ciliate; corolla widely campanulate, pure yellow, unspotted, sometimes with purple basal blotch, 3.5–4.5 cm; lobes 5, ca. 1.5 cm; stamens 10, unequal, shorter than corolla, filaments densely puberulent at base; ovary 5–6 mm, densely pale brown-tomentose; style green, ca. 2.5 cm, glabrous. Capsule oblong-cylindric, slightly curved, 20–30 × ca. 5 mm, hairy. Fl. Apr–May, fr. Sep–Oct.
Abies forests, Rhododendron thickets, mountains; 3000–4100 m. W Yunnan.