Thanh Hoa Prov., Thuong Xuan Distr., Van Xuan Municipality, Hang Cao village, Xuan Lien Natural Reserve. Remnants of primary and secondary broad-leaved evergreen forest on highly eroded rocky limestone hills at elevation 100-200 m a.s.l. around point 19°50’47.2’’N 105°14’42.7’’E. Lithophytic herb on very steep, rocky slope. Common.