Vientiane prov., Kasi distr., between Pa Chao and Nam Ken villages, Pa Chao Mt., around point 19°19'35.5''N 102°22'57.7''E. Secondary broad-leaved evergreen dry forest on very steep rocky mountain slopes composed by solid marble like highly eroded limestone at elev. 1100-1200 m a.s.l. Lithophyte on shady vertical cliff on shady steep rocky slope. Not common.