N.Vietnam, Bac Kan Prov., Cho Don Distr., Ban Thi Municipality, village Phia Khao, Lung Li valley, around point 22°16′10′'N, 105°31′01′'E, Cot Moc mountain at elevation 800-900 m a.s.l.
Primary broad-leaved evergreen closed forest on very steep slopes and cliffs near tops of rocky ridge composed with solid marble-like stratified limestone.
Lithophyte in crevices of vertical cliffs. Flowers: tepals white, red-purple outside, anthers and stigmata yellow. Leaves deep green-brown with light green nerves above, dull brown-violet with light green nerves below. Very common. HAL 4796 23 May 2004 (Photo).