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. Terrestrial sedge on very steep rocky slopes. Very common. Usual codominante of herb forest stratum at 450-550 m a.s.l.