Description from Flora of China
Cupia mollissima Hooker & Arnott, Bot. Beechey Voy. 192. 1833; Mussaenda kuliangensis F. P. Metcalf; Stylocoryna mollissima (Hooker & Arnott) Walpers; Tarenna incana Diels.
Shrubs or small trees, 1-6 m tall; branches densely gray or brown pilosulous or tomentulose, becoming glabrescent when old. Petiole 0.4-2.5 cm, densely pilosulous or tomentulose; leaf blade drying papery and blackish brown, lanceolate, oblong-lanceolate, or ovate-elliptic, 4.5-22.5 × 1-10 cm, adaxially moderately to densely hispidulous to pilosulous, abaxially densely pilosulous, tomentulose, or villosulous, base cuneate, acute, or obtuse, apex acuminate or long acuminate; secondary veins 5-12 pairs, apparently without domatia; stipules generally persistent, interpetiolar or shortly united around stem, ovate to triangular, 5-8 mm, densely strigillose to pilosulous, acute to cuspidate. Inflorescences corymbose, 4-8 cm, many flowered, densely pilosulous to tomentulose, sessile and subtended by a pair of somewhat reduced leaves; bracts linear, 1-3 mm; pedicels 3-6 mm. Flowers pedicellate. Calyx densely tomentulose to pilosulous; hypanthium portion ellipsoid to subglobose, 1.5-2 mm; limb 1-1.8 mm, lobed shallowly to deeply; lobes triangular to spatulate, rounded to acute. Corolla white, outside densely strigillose to hirtellous; tube 3-4 mm, densely villous at throat; lobes narrowly oblong, 4-5 mm, obtuse to rounded. Ovules ca. 15 per cell. Berry subglobose, 5-7 mm in diam., pilosulous, villosulous, or sometimes glabrescent; seeds 7-30. Fl. May-Jul, fr. May-Jan.
W. C. Chen (in FRPS 71(1): 377. 1999) described the corollas as ca. 1.2 cm, but this length has not been seen on the numerous specimens studied.
Forests or thickets at streamsides, on hills, or on mountains; 200-1100 m. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangxi, Yunnan, Zhejiang [Vietnam].