N. Vietnam, Hoa Binh prov., Mai Chau distr., Hang Kia municipality, near Hang Kia village, (20°44′21′'N, 104°53′57′'E). Primary wet broad-leaved evergreen closed forest on of highly eroded remnant karst limestone ridge at elev. 1100-1200 m a.s.l. Herb vine 5-6 m hg on open rocky place. Flowers reddish-brown with strong unpleasant smell. Not rare.