N.Vietnam, Cao Bang Prov., Trung Khanh Distr., Ngoc Khe Municipality, Pac Nga village, around point 22є54'59''N, 106є31'44''E, at elevation 800-850 m a.s.l. Remnants of primary evergreen broad-leaved forest along tops of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone. Tree 8-12 m tall. Very common. Co-dominant of 1-2 forest stratum.