Pilostigma inflexum Costantin in Lecomte, Fl. Indo-Chine 4: 73. 1912; Costantina inflexa (Costantin) Bullock; Tylophora hainanensis Tsiang.

Lianas to 3 m. Branchlets pubescent along 1 line, glabrescent. Petiole 0.5-2.5 cm, adaxially ciliate; leaf blade ovate or ovate-oblong, 3-6.5 × 1.5-4 cm, membranous, puberulent, sometimes abaxially glabrescent, base rounded to cordate, apex acuminate; lateral veins 3 or 4 pairs. Inflorescences shorter than leaves, to 8-flowered. Pedicel 4-6 mm. Sepals ovate, ca. 1.5 × 1.3 mm, pubescent outside, glabrous inside, ciliate. Corolla white; tube ca. 1 mm; lobes 2.5-3 × 0.8-1 mm, glabrous outside, puberulent inside. Corona lobes ovate, apex obtuse. Stigma head depressed, broader than ovary. Follicles lanceolate, 5-7 × ca. 1 cm, glabrescent. Seeds oblong, ca. 1 cm; coma ca. 3 cm. Fl. Jul-Oct, fr. Sep-Dec.

Thickets, open woods; 100-300 m. Guangdong, Guangxi, Hainan [Vietnam].