不丹杜鹃 bu dan du juan

Rhododendron aucklandii J. D. Hooker; R. griffithianum var. aucklandii (J. D. Hooker) Hooker; R. oblongum Griffith.

Shrubs or small trees, evergreen, 1.3–4(–10) m tall; shoots ca. 4 mm in diam. below inflorescence; young shoots stout, glabrous. Petiole stout, 20–35 mm, glabrous; leaf blade leathery, oblong to oblong-elliptic or oblong-ovate, 10–19(–30) × 4.5–12 cm; base rounded or subcordate; apex acute to rounded and apiculate; abaxial surface glabrous; adaxial surface green, smooth; midrib prominent abaxially, grooved adaxially; lateral veins 19–24-paired, distinct on both surfaces. Inflorescence umbellate, 4- or 5-flowered; rachis 50–70 mm. Pedicel glabrous, 3.5–4 cm; calyx cupular, 7–20 mm, glabrous or sparsely glandular-hairy; corolla campanulate, pink at first, later white, 5.5–8 cm, glabrous; lobes 5, suborbicular, ca. 2 × 3.5 cm, emarginate; stamens 12–18, filaments glabrous; ovary ovoid, ca. 7 mm, glandular; style glandular to tip; stigma swollen. Capsule cylindric, ca. 35 × 15 mm.

Broad-leaved forests, Rhododendron thickets; 2100–2800 m. S Xizang [Bhutan, N India, E Nepal, Sikkim].