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 700-750 m a.s.l.
Secondary wet closed evergreen forest on steep rocky slopes of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone.
Lithophytic herb up to 0.5 m tall on shady rocky slope. Flowers greenish, leaves deep green above, deep purple-violet below. Very common. Co-dominant of herbaceous forest stratum on low part of slopes and on rocky valleys.