182. Rhododendron rupivalleculatum P. C. Tam, Guihaia. 2: 69. 1982.
岩谷杜鹃 yan gu du juan
Small shrubs, epiphytic, 0.2–0.6 m tall. Stem cylindric, multi-branched; young shoots rough, densely papillate. Petiole ca. 3 mm or sessile; leaf blade leathery, spatulate-obovate, 1.4–2 × 0.8–1 cm; base cuneate; margin conspicuously revolute; apex emarginate, apiculate; abaxial surface pale green, sparsely scaly; adaxial surface olive green, shiny; midrib conspicuous, lateral veins inconspicuous. Inflorescence terminal, 1-flowered. Pedicel slender, 1–1.5 cm, scaly, pubescent; calyx 5-lobed; lobes ca. 1.2 mm, oblong, sparsely scaly, pubescent; corolla shortly campanulate, yellow, 3 lobes with red spots, 1–1.2 cm, outer surface sparsely scaly; lobes spathulate-ovate, longer than tube; stamens 10, 0.8–1 cm, filaments pubescent around the middle; ovary scaly, densely pubescent; style often arched, ca. 5 mm. Capsule cylindric, 9–12 × ca. 3.5 mm, scaly, pubescent and densely glandular. Fl. Jul–Sep, fr. Nov–Jan.
Rocks in open valley forests, summits of open hills; 1200–1400 m. Guangdong, Guangxi.
This species is closely allied to Rhododendron poilanei.