54. Rhododendron zaleucum I. B. Balfour & W. W. Smith, Notes Roy. Bot. Gard. Edinburgh. 10: 163. 1917.
白面杜鹃 bai mian du juan
Shrubs or small trees, 1–3(–6) m tall; young shoots sparsely scaly. Petiole 7–13 mm, sparsely brown-scaly; leaf blade elliptic, ovate-lanceolate, or lanceolate, 4–7 × 1–2.5 cm; base cuneate to rounded; apex acute to acuminate, apiculate; abaxial surface pinkish white, papillate, scales 1.5–4 × their own diameter apart, unequal, yellow, glabrous or pubescent, at least along midrib; adaxial surface without scales, sparsely pubescent along midrib when young. Inflorescence terminal, shortly racemose, 3–5-flowered; rachis 2–5 mm, scaly, otherwise glabrous, rarely pubescent. Pedicel 1–1.5 cm, sparsely scaly; calyx rimlike or 5-lobed; lobes ca. 1 mm, rounded or ovate-triangular, scaly, glandular; corolla broadly funnelform-campanulate, 5-lobed to the middle, white to pink, 3–4 cm, outer surface densely glandular scaly, tube sometimes pubescent; lobes rounded-ovate; stamens unequal, 1.3–3.3 cm, longer than corolla; filaments at base spreading-pubescent; ovary 5-locular, densely scaly; style long, glabrous or pubescent at base. Capsule cylindric, 8–15 mm. Fl. Apr–Jul, fr. Jul–Aug.
Conifer-Rhododendron forests, thickets on slopes; 2800–3400 m. Yunnan [Myanmar].