N.Vietnam, Bac Kan Prov., Cho Don Distr., Ban Thi Municipality, village Phia Khao, around point 22°15′35′'N, 105°31′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. Woody vine 6-8 m long among secondary shrubs along road. Not common.