云上杜鹃 yun shang du juan

Rhododendron pilicalyx Hutchinson; R. rufosquamosum Hutchinson; R. scottianum Hutchinson, nom. illeg. superfl.; R. supranubium Hutchinson.

Shrubs, rarely small trees, rarely epiphytic, 1–4(–5) m tall; young shoots densely brown-scaly, otherwise glabrous. Petiole 6–16 mm, densely scaly, sometimes long-villous; leaf blade leathery, elliptic, elliptic-lanceolate or obovate, 6–11 × 2–5 cm; base narrower; apex acuminate or acute; abaxial surface gray white, scales less than 1 × their own diameter apart to nearly contiguous, sometimes 1 × their own diameter apart, brown or brownish red; adaxial surface sparsely scaly; midrib and lateral veins raised abaxially, concave adaxially; lateral veins thin. Inflorescence terminal, umbellate, (2–)3(–4)-flowered. Pedicel 0.5–1 cm, densely scaly; calyx undeveloped, 5-lobed; lobes ca. 1 mm, rounded or triangular, persistent in fruit, scaly; corolla broadly funnelform, white tinged with pale red, inside with pale yellow markings, 5–7 cm, densely scaly, tube gray-white-pubescent outside; stamens 10, unequal, long ones half as long as corolla lobes; filaments pubescent below; ovary (5 or)6-locular, densely scaly; style rarely longer than corolla, basal part scaly. Capsule ovoid or cylindric-ovoid, 15–25 mm. Fl. Mar–May.

Mixed forests, thickets, open areas on rocky mountains, dry slopes; 1200–2800(–3100) m. Yunnan [NE Myanmar].

Cullen (Notes Roy. Bot. Gard. Edinburgh 39: 47, 53. 1980) maintained Rhododendron rufosquamosum as a species distinct from R. pachypodum.