FLORA OF VIETNAM Orchidaceae Biermannia calcarata Aver.
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 600-650 m a.s.l.
Closed secondary broad-leaved evergreen wet forest on very steep rocky slopes of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone.
Canopy epiphyte on shrubs 3-4 m tall in very wet shady mossy place. Flowers light yellowish. Rare.