N.Vietnam, Cao Bang Prov., Trung Khanh Distr., Ngoc Khe Municipality, Pac Nga village, around point 22°54′59′'N, 106°31′44′'E, at elevation 700-800 m a.s.l.
Secondary broad-leaved evergreen wet closed shady forest on very steep slopes and cliffs of rocky ridges and mesae composed with light gray solid marble-like crystalline limestone.