Description from Flora of China
Shrubs, 1.5–3 m tall; young shoots densely yellowish gray-tomentose. Leaf blade thickly leathery, ovate-oblong to oblanceolate, 5–11 × 2–4 cm; base cuneate; margin slightly revolute; apex acute, apiculate; abaxial surface indumentum rust-red to dark brown, dense, 1-layered, hairs fasciculate to stellate; adaxial surface coarsely bullate-rugose, glabrescent; midrib, lateral and net veins deeply impressed adaxially. Inflorescence racemose-umbellate, 8–10-flowered; rachis 5–8 mm, yellowish pubescent. Pedicel 1.5–2 cm, densely floccose-tomentose with a few glandular hairs; calyx lobes 5, ca. 2 mm, triangular, densely floccose; corolla funnel-campanulate, white to pink, with red spots inside, 3–4 cm, puberulent at base inside, lobes 5; stamens 10, unequal, filaments puberulent in lower half; ovary ca. 5 mm, densely rust-red woolly-tomentose; style ca. 2.3 cm, glabrous, stigma capitate, green. Capsule cylindric, slightly curved, 15–20 × 4–5 mm, tomentose. Fl. May–Jun, fr. Aug–Oct.
Rhododendron dayiense M. Y. He (Acta Phytotax. Sin. 35: 63. 1997), described from C Sichuan (Dayi), needs to be considered. It is said to be closely allied to R. wiltonii, but differs in the longer pedicel, 2.8–3.2 cm, in the larger calyx, 4–5 mm, in the red corolla, and in the densely reddish brown hispid ovary, with red-brown hairs at the base of the style.
Forests, high mountains; 2200–3300 m. W Sichuan.