藏东杜鹃 zang dong du juan

Small trees, 4–5 m tall; young shoots ca. 6 mm in diam., sparsely grayish tomentose, soon glabrescent. Petiole terete, 15–20 mm, sparsely floccose; leaf blade leathery, oblong to ovate-oblong, 15–17 × 4–4.8 cm; base cuneate or broadly cuneate; margin slightly revolute; apex obtuse or acute and mucronate; abaxial surface silvery-white indumentum thin, compacted and agglutinated; adaxial surface glabrous, midrib markedly elevated abaxially, impressed adaxially; lateral veins 22–23-paired, conspicuous abaxially. Inflorescence racemose-umbellate, ca. 16-flowered; rachis ca. 25 mm, floccose. Pedicel 1–1.5 cm, densely pale brown-tomentose; calyx lobes 5, 1–1.5 mm, sparsely tomentose; corolla campanulate, bright crimson, purple within at base of tube, ca. 4 cm, lobes 5, suborbicular, emarginate; stamens 10, unequal, filaments glabrous; ovary 6–7 × ca. 3.5 mm, 6-locular, densely pale brown-tomentose; style slightly shorter than corolla and longer than stamens, glabrous; stigma slightly lobulate. Fl. May.

Abies forests on mountain slopes; 2800–2900 m. SE Xizang (Mêdog).

The 5-lobed corolla suggests that this species is only doubtfully a member of Rhododendron subsect. Grandia. It may be related to, or a synonym of, R. lanigerum in R. subsect. Arborea.