N.Vietnam, Thanh Hoa Prov., Quan Hoa Distr., Phu Le Municipality, Hang village, around point 20°32′29′'N, 105°04′32′'E. Secondary open evergreen seasonal broad-leaved lowland forest with bamboo on very steep slope of rocky ridge composed with crystalline marble-like highly eroded limestone at elev. 200-350 m. Vine. Common.