29. Rhododendron leptocladon Dop in Lecomte, Fl. Indo-Chine. 3: 745. 1930.
金平林生杜鹃 jin ping lin sheng du juan
Rhododendron nemorosum R. C. Fang.
Shrubs, epiphytic, 0.5–1 m tall; young shoots densely brown-scaly, otherwise glabrous. Petiole 5–7 mm, densely brown-scaly, glabrous; leaf blade leathery, elliptic, oblong-elliptic or ovate, 4–6(–8) × 2–3.5 cm; base cuneate to rounded; apex acute, apiculate; abaxial surface gray green, scales contiguous, or less than their own diameter apart, unequal, brown, without hairs; adaxial surface green, glabrous; midrib raised abaxially, concave adaxially; lateral veins 6-paired, slightly concave above and raised below, or inconspicuous on both surfaces. Inflorescence terminal, umbellate, 3- or 4-flowered. Pedicel stout, 0.3–0.4 cm, densely scaly; calyx 5-lobed; lobes 1–2 mm, ovate, apex rounded, densely scaly abaxially; corolla broadly funnelform, lobed to the middle, yellow, 3.5–4.3 cm, outer surface sparsely scaly, tube gray-white-pubescent, lobes 5, ovate; stamens 10, unequal, shorter than corolla; filaments densely spreading pubescent at base, anthers brown, ca. 5 mm; ovary densely scaly; style slightly longer than corolla, basal part scaly. Capsule ovoid-cylindric, 5-lobed, ca. 11 mm, densely scaly.
Forests, often epiphytic on trees; 2000–2300 m. S Yunnan [N Vietnam].
One of us (Chamberlain) has observed this species in the field in Vietnam. Research at Edinburgh by T. Holland (A bio-geographical study of Vietnamese Rhododendron. MSc thesis, University of Edinburgh. 1997) has shown that R. nemorosum is synonymous with R. leptocladon.