Cao Bang Prov., Bao Lac Distr., Hong An municipality, Mi Lung village. Primary broad-leaved and mixed humid evergreen forest on very steep slopes and along rocky ridge composed with solid crystalline highly eroded limestone at elevation 1400-1450 m a.s.l. around point 22°49’23.4’’N 105°49’54.5’’E. Lithophytic fern on mossy shady rocks on very steep slope. Common.