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 wet forest on alluvial foothills of highly eroded remnant limestone ridge at elev. 350-450 m a.s.l. Lithophytic and terrestrial herb up to 1 m hg on steep rocky slope. Common.