柳条杜鹃 liu tiao du juan

Rhododendron oleifolium Franchet; R. virgatum var. glabriflorum K. M. Feng ex R. C. Fang; R. virgatum subsp. oleifolium (Franchet) Cullen; R. virgatum var. oleifolium (Franchet) Demoly.

Small shrubs, (0.1–)1–2 m tall; branches in upper part, slender, brown, densely scaly. Petiole 3–4 mm, densely brown scaly; leaf blade leathery, narrowly oblong or oblong-lanceolate, 2–5.5 × 0.9–2 cm; base cuneate to rounded; margin revolute; apex obtuse or acute, apiculate; abaxial surface gray-green, scales less than or equal to their own diameter apart, dimorphic, rimless or, more commonly, with an obvious margin; adaxial surface densely scaly, rapidly glabrescent, lateral veins more conspicuous below, inconspicuous above. Inflorescences several, axillary, arranged in a compound raceme, 1- or 2-flowered, bud scales persistent, imbricate, glabrous or slightly gray-white-pubescent. Pedicel 0.3–0.4 cm, densely scaly; calyx lobes 1–2 mm, oblong or semicircular, apex rounded, sparsely scaly; corolla funnelform to campanulate, lobed above the middle, light red, occasionally white, 1.5–2 cm, outer surface densely scaly, with gray hairs, rarely glabrous; lobes 5, spreading; stamens 10, unequal, long ones nearly equaling corolla, filaments pubescent or glabrous towards the base; ovary 5-locular, densely scaly; style exserted from corolla, basal half densely scaly, pubescent, sometimes glabrous. Capsule cylindric or globose, 7–12 mm, densely scaly. Fl. Mar–May.

Forest margins, among shrubs, wet grasslands; 1700–3000 m. SE Xizang, W Yunnan [Bhutan, Sikkim].

This species is difficult to subdivide into subspecies, as the characters that have been used to separate them in the past are very variable. These characters include the corolla length and the number of scales and amount of pubescence on the style bases and outer surface of the corolla. Cullen (Notes Roy. Bot. Gard. Edinburgh 39: 130. 1980) maintained Rhododendron virgatum subsp. oleifolium as distinct.