Description from Flora of China
Climbing shrubs; branches terete, sparsely strigillose to glabrescent. Leaves opposite; petiole 3-10 mm, densely strigillose to glabrescent; blade drying membranous, elliptic-oblong, elliptic, or oblanceolate, 7-11(-18) × 2-5.5 cm, adaxially sparsely strigillose to glabrescent, abaxially moderately to sparsely strigillose with pubescence denser on veins, base acute to obtuse, apex acuminate; secondary veins 4-6 pairs, tertiary venation visible and reticulate; stipules deciduous, triangular to ovate, 3-6 mm, densely strigillose, deeply 2-lobed, lobes narrowly triangular to linear. Inflorescence laxly cymose, usually regularly dichotomous, ca. 5 × 4-5 cm, strigillose to glabrescent, pedunculate; peduncles 3.5-4 cm; bracts subulate, 1-3 mm; pedicels 1-5 mm. Flowers pedicellate (or on higher order inflorescence axes). Calyx with hypanthium portion ellipsoid to turbinate, 2-3 mm, glabrous; lobes narrowly triangular to linear, 1-2 mm, strigillose, 1 lobe on 1 flower of most inflorescences enlarged into calycophyll, blade elliptic or ovate, 3-5 × 2-3 cm, sparsely puberulent to strigillose especially on veins, base obtuse, stipe 15-24 mm, apex acute to obtuse. Corolla yellow, outside sparsely to moderately strigillose; tube 22-31 mm, inside with clavate hairs at inflated throat; lobes broadly ovate, 3-4 mm, inside densely yellow papillose. Berry subglobose or ellipsoid, 8-10 × 5-7 mm, glabrous, with calyx limb caducous. Fl. May-Dec.
H. H. Hsue and H. Wu (in FRPS 71(1): 296. 1999) gave the corolla tube length of this species as 22-25 mm, but the corolla tube of the type specimen is ca. 31 mm; this report is added here.
● Wet sites in dense forests; ca. 900 m. S Hainan.