草原杜鹃 cao yuan du juan

Rhododendron diacritum I. B. Balfour & W. W. Smith; R. drumonium I. B. Balfour & Kingdon Ward; R. idoneum I. B. Balfour & W. W. Smith; R. pycnocladum I. B. Balfour & W. W. Smith.

Small densely branched, prostrate shrubs, usually forming cushions, (0.1–)1 m tall; branches scaly. Petiole 0.3–3 mm, scaly; leaf blade lanceolate, narrowly or broadly elliptic or orbicular, 0.3–1.2(–1.4) × 0.15–0.5(–0.65) cm; base cuneate; apex acute to rounded, strongly mucronate; abaxial surface golden fawn, pale orange, brown to reddish brown, scales overlapping, mostly pale gold to reddish brown, with few to many darker scales among them; adaxial surface dark green, scales overlapping, pale golden. Inflorescence 1- or 2(–3)-flowered. Pedicel 0.05–0.15(–0.2) cm, scaly; calyx reddish purple or green; lobes 0.5–2(–3) mm, triangular, ovate to rounded, usually unequal, scaly, margin scaly and long-ciliate; corolla broadly funnelform, lavender, rose pink to deep purplish blue, (0.6–)0.7–1.1(–1.4) cm, tube 2–4 mm, outer surface scaly, often also pubescent, throat pubescent; stamens (8–)10(–11), as long as corolla, filaments pubescent towards base; ovary 1.5–2.5(–3) mm, scaly; style 0.3–1.7 cm, rarely pubescent and scaly at base. Capsule ovoid to cylindric, 3–4 mm, densely scaly. Fl. May–Jul, fr. Aug–Oct.

Forest margins, Rhododendron thickets, rocky slopes, cliffs; (2700–)3200–3800(–5000) m. W Sichuan, C and N Yunnan.