N.Vietnam, Bac Kan Prov., Cho Don Distr., Ban Thi Municipality, village Phia Khao, around point 22є15'35''N, 105є31'17''E at elevation
800-900 m a.s.l. Remnants of primary broad-leaved evergreen closed wet forest on very steep slopes and cliffs of rocky ridges and mesae composed with solid marble-like stratified limestone. Lithophytic herb in crevices of vertical cliffs. Flowers blue.