N. Vietnam, Son La prov., Moc Chau distr., Van Ho municipality, near Hua Tat village (20°46′13′'N, 104°46′12′'E). Primary broad-leaved evergreen closed wet forest along remnant limestone highly eroded ridge at elev. 1100-1300 m a.s.l. Terrestrial and lithophytic herb 0.5-0.7 m hg. Flowers yellowish-green. Very common.