FLORA OF VIETNAM Polypodiaceae s.l. Onichium sp. ?
Vietnam, Ha Giang Prov., Hoang Su Phi Distr., Ho Thau Municipality, around Chien Thang village, about 4 km to NW of Ho Thau village (22°37′24″N, 104°38′00″E) at elev. 1600-1800 m a.s.l.
Primary closed cloud evergreen broad-leaved forest with Rhodoleya and Rhododendrons along ridge composed with shale and granite with quartzite.
Lithophytic fern on vertical shady cliff. Occasional.