Description from Flora of China
Rhododendron weldianum Rehder & E. H. Wilson.
Shrubs or small trees, 1.5–8 m tall; shoots densely whitish to tawny floccose when young, soon glabrescent. Petiole 15–20 mm, initially with floccose hairs, later glabrescent; leaf blade leathery, elliptic to oblong-ovate, 6.5–11 × 3–5 cm; base subrounded or broadly cuneate; apex obtuse or acute, mucronate; abaxial surface with indumentum 2-layered, upper layer thick, soft, rust-yellow to rufous, woolly-tomentose, hairs branched, lower layer compacted, gray-white; adaxial surface slightly shiny, glabrous. Inflorescence racemose-umbellate, 6–11-flowered; rachis ca. 5 mm, densely rusty brown-pubescent. Pedicel 1–1.5 cm, densely gray floccose; calyx lobes 5, ca. 1 mm, broadly triangular, floccose outside; corolla funnel-campanulate, white to pale pink, with crimson spots on upper lobes, 2–3 cm, puberulent at base inside; lobes 5, slightly unequal; stamens 10, 1.2–2 cm, filaments white-puberulent at base; ovary ca. 4 mm, densely gray-brown woolly-tomentose, sometimes with few glandular hairs at apex; style ca. 2 cm, glabrous or with few hairs at base. Capsule oblong-cylindric, slightly curved, 20–25 × 5–7 mm. Fl. May–Jun, fr. Jul–Sep.
Rhododendron rufum var. glandulosum G. H. Wang (Bull. Bot. Res., Harbin 15: 428. 1995) was described from S Gansu (Kangle). It is said to differ from the typical variety in having a densely stipitate-glandular ovary. However, no material fitting this description was seen, and it is therefore uncertain if this entity actually belongs within R. rufum.
Forests, mountain slopes; 2300–3800 m. C and SW Gansu, E and S Qinghai, SW Shaanxi (Taibai Shan), N and W Sichuan.