N. Vietnam, Thanh Hoa prov., Ba Thuoc distr., Co Lung municipality, territory of Pu Luong protected area, near Co Lung village, Nui Doan (Pha Doan) mountain system (20°26′30′'N, 105°11′32′'E). Primary evergreen broad-leaved wet forest on steep slopes of remnant highly eroded karst limestone ridge at elev. 350-450 m a.s.l. Vine 5-6 m hg. Flowers green with yellow tops of tepals. Not common.