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 on slopes of remnant limestone highly eroded ridge at elev. about 1200 m a.s.l. Lithophytic fern on vertical shady cliffs. Not rare.