N.Vietnam, Thanh Hoa Prov., Quan Hoa Distr., Phu Le Municipality, Hang
village, around point 20°32′19′'N, 105°05′03′'E. Primary evergreen seasonal broad-leaved closed submontane forest on tops of rocky ridge composed with crystalline marble-like highly eroded limestone at elev. 750-800 m. Lithophyte and terrestrial herb 10-20 cm tall. Flowers purple-violet. Very common.