N. Vietnam, Thanh Hoa prov., Ba Thuoc distr., Co Lung municipality, territory of Pu Luong protected area, near Pu Luong village (20°27′01′'N, 105°11′03′'E). Primary very dry evergreen broad-leaved forest with Burrettiodendron hsienmu along tops of remnant karst limestone ridge at elev. 500-550 m a.s.l. Woody vine 8-10 m hg in open place. Flowers white. Not common.