N. Vietnam, Hoa Binh prov., Da Bac distr., 4-6 km to the N of Doan Ket village, Phu Canh mountain system (20°55′48′'N, 105°02′52′'E). Open secondary broad-leaved evergreen mountain forest on steep shale slopes at elev. 800-900 m a.s.l. Climbing shrub up to 3 m hg. Flowers yellowish-green, inner tepals inside purple. Not common.