293. Rhododendron tanastylum I. B. Balfour & Kingdon Ward, Trans. Bot. Soc. Edinburgh. 27: 217. 1917.
光柱杜鹃 guang zhu du juan
Small trees or shrubs, 2–6 m tall; older shoots glabrous; young shoots glabrescent. Petiole stout, terete, 10–15 mm, glabrous; leaf blade leathery, sometimes thinly so, ovate-lanceolate to elliptic, 6–17 × 2.5–5.5 cm; base rounded or broadly cuneate; margin not undulate; apex acuminate or obtuse; both surfaces glabrous; abaxial surface paler; adaxial surface matt at maturity; midrib raised; lateral veins 17–20-paired. Inflorescence racemose-umbellate, 4–8-flowered; rachis 10–20 mm, glabrous. Pedicel ca. 1 cm; calyx cupular, lobes 5, 1–3 mm, ovate or triangular, glabrous; corolla tubular campanulate, fleshy, white or pink to deep crimson, with darker spots, 4–4.5 cm, 5 black nectar pouches at base; lobes 5, orbicular, 2–2.5 cm, emarginate; stamens 10, unequal, 2–3.5 cm, filaments glabrous or puberulent at base; ovary conical, 5–8 × ca. 3 mm, glabrous or slightly pubescent; style stout, 3–3.5 cm, glabrous, stigma discoid. Capsule oblong, blunt, ca. 17 × 7 mm, glabrous. Fl. Mar–May, fr. Sep–Nov.
Evergreen broad-leaved forests, Pinus forests, thickets, valleys; 1700–3700 m. E Xizang, W Yunnan [NE India, NE Myanmar].
