N. Vietnam, Hoa Binh prov., Da Bac distr., about 2-3 km to the E of
Doan Ket village (20°54′55′'N, 105°02′18′'E). Primary broad-leaved evergreen mountain wet forest on silicate sandstones at elev. 900-1136 m a.s.l. Terrestrial herb up to 1.5 m hg on wet very steep slope. Flowers yellowish. Very common.