Tuyen Quang Prov., Na Hang Distr., Sinh Long Municipality, Khuoi Phin village, around point 22°38′21″N, 105°20′28″E.
Primary evergreen mixed humid forest on rocky limestone on highly eroded karstic hills composed with gray solid marble-like limestone at elevation 1100-1200 m a.s.l.
Creeping lithophytic fern on shady rocks. Leaves uniform dark green. Very common.