Vincetoxicum taihangense (Tsiang & Zhang) C. Y. Wu & D. Z. Li

Stems simple, to 1.5 m, hollow when dry, puberulent, basal part erect, apical part twining. Leaves opposite; petiole 1-3.5 cm; leaf blade narrowly elliptic to elliptic, 8-23 × 2.5-10 cm, membranous or thin papery, pubescent to puberulent, base cuneate, apex acuminate or caudate-acuminate; lateral veins 6-8 pairs. Inflorescences umbel-like, usually dichotomous, shorter than leaves; peduncle 2-5 cm, puberulent. Pedicel 1-2 cm. Sepals lanceolate, 1.5-2.5 × 0.5-0.7 mm, puberulent to glabrous outside, ciliate; basal glands present or absent. Corolla yellow-green, rotate; tube short; lobes oblong, 5-7.5 × 2-2.5 mm. Corona slightly shorter than gynostegium; lobes broadly ovate-triangular, obtuse to subacute, adnate to anthers. Anthers nearly square, apical membrane ovate-triangular; pollinia oblong. Stigma head elevated. Fl. Jun-Aug.

* Thickets along valleys. Anhui, Shanxi.

Cynanchum gracilipes Tsiang & Zhang; Vincetoxicum gracilipes (Tsiang & Zhang) C. Y. Wu & D. Z. Li; V. taihangense (Tsiang & Zhang) C. Y. Wu & D. Z. Li.