N. Vietnam, Tuyen Quang prov., Na Hang distr., Xuan Tam municipality, near Ban Cai village (22°29′18′'N, 105°19′47′'E). Primary broad-leaved evergreen dry forest on very steep slopes of highly eroded remnant limestone ridge at elev. 450-500 m a.s.l. Lithophyte herb on vertical cliffs. Abundant, usual codominante of lithophytic herb communities.