543. Rhododendron tsoi Merrill, J. Lingnan Sci. 13: 42. 1934.
两广杜鹃 liang guang du juan
Rhododendron subenerve P. C. Tam var. nudistylum P. C. Tam.
Shrubs, 0.5–1 m tall, semievergreen; young shoots densely coarsely castaneous-brown-strigose. Summer and winter leaves different. Petiole 1–2.5 mm, coarsely castaneous-brown-strigose; leaf blade leathery, elliptic or obovate, broadly elliptic, 0.5–1.4 × 0.4–0.9 cm; base cuneate; margin slightly revolute, sparsely setose-ciliate; apex obtuse or subrounded, often mucronate; abaxial surface more densely strigose, especially on midrib; adaxial surface sparsely strigose or subglabrous. Inflorescence 3–5-flowered. Pedicel 0.3–0.4 cm, densely castaneous-brown-strigose; calyx lobes small, coarsely strigose, apex subtruncate; corolla narrowly funnelform, rose, ca. 1 cm; tube 3–4 mm, outer surface glabrous, inner surface sparsely pubescent; lobes oblong to oblong-ovate, 0.5–0.6 × 0.3–0.4 cm, apex rounded; stamens 5, ca. 0.9 cm, slightly shorter than the corolla, filaments flat, puberulent below; ovary ovoid, densely coarsely castaneous-brown-strigose; style ca. 0.7 cm, glabrous. Capsule oblong-ovoid, 4–5 mm, coarsely castaneous-brown-strigose. Fl. Apr–May, fr. Jun–Aug.
Open forests, arid mountains, meadows; 700–1600 m. S Guangdong, C and SW Guangxi.