N.Vietnam, Thanh Hoa Prov., Ba Thuoc Distr., Co Lung Municipality, Eo Dieu village, around point 20°26′06′'N, 105°13′51′'E. Secondary evergreen seasonal broad-leaved closed lowland forest on very steep slope of rocky ridge composed with crystalline marble-like highly eroded limestone at elev. 400-600 m. Terrestrial fern. Very common.