Description from Flora of China
Mussaenda dehiscens Craib, Bull. Misc. Inform. Kew 1916: 263. 1916; Emmenopterys rehderi F. P. Metcalf; M. elongata Hutchinson; M. henryi Hutchinson; Schizophragma macrosepalum Hu.
Shrubs to small trees, to 8 m tall; branches flattened or angled to terete, strigose to strigillose becoming glabrescent with age, often with sparse to rather dense ellipsoid lenticels. Petiole 0.5-1.6 cm, strigose to strigillose; leaf blade drying thinly papery, lanceolate, lanceolate-elliptic, or ovate-lanceolate, 10-17 × 2.5-6 cm, adaxially sparsely hirsute or strigose at least along principal veins to glabrescent, abaxially strigose to strigillose along principal lateral veins, sparsely strigose along higher order veins, and glabrescent on blade, base cuneate to rounded, apex acuminate or acute; secondary veins 7-10 pairs, infrequently with a few pilosulous domatia; stipules 5-14 mm, abaxially strigose to strigillose, 2-lobed for 1/4 to nearly completely. Inflorescences densely hirtellous to strigillose; peduncle 2.5-9 cm; branched portion 7-18 × 7-17 cm; bracts 3-15 mm, acute to acuminate. Calyx puberulent; ovary portion obovoid to ellipsoid, 1.5-2 mm; lobes narrowly triangular, 1-2 mm, acute; calycophyll puberulent to strigillose at least on veins and margins, blade drying papery, ovate to broadly ovate, 3-10 × 3-6 cm, 5-veined from near base, base cuneate or acuminate, apex acute or obtuse, with stipe 2-3 cm. Corolla strigose to strigillose outside; tube 18-22 mm, inside densely sulfur-yellow pilose in throat and similarly but more sparsely pubescent near base; lobes broadly ovate, 2.5-3 mm, acuminate to aristate with tip or arista 0.5-1 mm. Anthers ca. 3 mm. Capsule 6-8 × 4.5-5 mm; seeds 0.1-0.2 mm, minutely foveolate and sulcate. Fl. May-Oct, fr. Jul-Dec.
Forests; 100-1000 m. Guangxi, Yunnan [Laos, N Myanmar, N Thailand, N Vietnam].