大姚山杜鹃 da yao shan du juan

Small trees, 3–4 m; young branches slender, glandular-setose. Petiole 8–15 mm, grooved adaxially, glandular-setose; leaf blade narrowly oblanceolate or oblong-lanceolate, 8–13 × 1.8–2.5 cm; base cuneate; margin slightly revolute; apex acuminate; abaxial surface mostly sparsely short-setose, denser on midrib; adaxial surface glabrous; lateral veins 14–18-paired. Inflorescence subapical, 4- or 5-flowered, rachis ca. 5 mm. Pedicel 2.5–3.5 cm, densely gray-pubescent and sparsely glandular-setose; calyx with undulate rim; lobes triangular, to 1 mm, glabrous; corolla funnelform, pale rose, with a yellow blotch on upper lobe, 5–5.5 cm, tube 15–20 mm, outer surface glabrous; lobes 5, oblong-obovate to elliptic, 3.5–4 cm; stamens 10, shortly exserted, filaments puberulent below; ovary oblong-cylindric, densely yellowish tomentose; style 4–4.5 cm, glabrous. Capsule not known. Fl. May.

Mixed forest margins; 1100–1200 m. E Guangxi.

This species may be a hybrid between Rhododendron cavaleriei and R. championiae as it occurs with both these species and shares some characteristics with both.