矮生杜鹃 ai sheng du juan

Rhododendron lampropeplum I. B. Balfour & Forrest.

Dwarf shrubs, 0.6–1.5 m tall; branchlets slender, with very short internodes, 3–4 mm in diam., densely rufous to gray-brown tomentose; bud scales persistent. Petiole 4–5 mm, densely thick rufous woolly-tomentose; leaf blade thickly leathery, oblong to oblanceolate, 2–4 × 0.5–1 cm; base attenuate-cuneate; margin strongly revolute; apex blunt-rounded with small and introrse curved sharp point; abaxial surface with indumentum 2-layered, upper layer rust-red, thick, woolly, hairs long-branched, lower layer thin, appressed; adaxial surface slightly rugulose, glabrous. Inflorescence compact, umbellate, ca. 8-flowered; rachis ca. 5 mm. Pedicel ca. 1 cm, densely rufous-tomentose; calyx lobes 5, ca. 2 mm, subtriangular, glabrous or only tomentose at base outside, margin ciliate; corolla funnelform, white to pale yellow, with crimson spots on corolla-tube and on upper lobes, ca. 3 cm, lobes 5, slightly unequal; stamens 10, unequal, filaments white-puberulent in lower 1/2; ovary ca. 4 mm, densely rusty red-fasciculate branched-tomentose; style shorter than corolla and longer than stamens, glabrous. Capsule oblong-cylindric, ca. 10 × 5 mm, ± hairy. Fl. Jun–Jul, fr. Sep–Oct.

Thickets, high mountains; 3600–4500 m. SW Sichuan, SE Xizang, NW Yunnan.

Field observations indicate that this species hybridizes extensively in the wild, especially with Rhododendron aganniphum and perhaps also with R. roxieanum. Indeed, R. roxieanum var. parvum Davidian (Rhododendron Spec. 2: 308. 1989), described from China, is either a synonym of R. proteoides or a hybrid of it.