N.Vietnam, Thanh Hoa Prov., Quan Hoa Distr., Phu Le Municipality, Hang village, around point 20°31′33′'N, 105°05′06′'E. Primary evergreen seasonal broad-leaved closed lowland forest on steep slopes of rocky ridge composed with crystalline marble-like highly eroded limestone at elev. 500-550 m. Semishrub 1-1.5 m tall. Flowers yellow. Very common.