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 800-850 m a.s.l. Remnants of primary broad-leaved and coniferous forest on ridge tops and on very steep slopes and cliffs of rocky ridges and mesae composed with light gray solid marble-like highly eroded crystalline limestone. Creeping lithophyte and occasionally epiphyte. Leaves deep green above, deep violet below. Occasional. No HAL 5465 9 June 2004.