Quang Binh Prov., Tuyen Hoa Distr., Lam Hoa municipality, Chuoi village, around point 17°56’51”N 105°49’18”E. Primary broadleaved evergreen dry forest on very steep slopes and on tops of rocky ridge composed with highly eroded crystalline limestone at elev. 200-250 m a.s.l. Lithophytic semi woody vine to 2 m long on open rocks along rocky ridge. Locally abundant.