老君山杜鹃 lao jun shan du juan

Rhododendron laojunense T. L. Ming.

Small trees or shrubs, 2–3 m tall; older branches roughish, glabrous; branchlets stout; young shoots grayish, densely tomentose. Petiole cylindric, 10–15 mm, thinly woolly; leaf blade leathery, elliptic or elliptic-lanceolate, 6–8 × 2–2.8 cm; base rounded; margin usually revolute or undulate; apex cuspidate or obtuse; abaxial surface pale green, verruculose, base thinly woolly; adaxial surface green, glabrous; midrib raised abaxially, grooved adaxially; lateral veins 11–13-paired. Inflorescence racemose-umbellate, 2–4-flowered; rachis 8–10 mm, densely brown-floccose. Pedicel 1–2 cm, with similar hairs; calyx lobes 5, ca. 2 mm, ovate-triangular, pubescent outside, glabrous within; corolla funnelform, pale yellow, 2–2.5 cm, lobes 5, suborbicular, ca. 1 × 1.2 cm, emarginate; stamens 10, unequal, 1–1.5 cm, filaments glabrous; ovary cylindric, ca. 5 mm, densely hirsute; style ca. 1.5 cm, glabrous, stigma slightly swollen. Capsule oblong-cylindric, base oblique, 15–20 × 6–7 mm, hirsute. Fl. May–Jun, fr. Jul–Aug.

Stony forests, bamboo forests, thickets, mountain summits; 2400–2600 m. SE Yunnan (Maguan, Malipo).