N.Vietnam, Bac Kan Prov., Cho Don Distr., Ban Thi Municipality, Phia Khao village, Cau Muc locality 22°17′32′'N 105°31′27′'E.
Primary closed evergreen wet broadleaved forest on very steep slopes and cliffs of remnant mountains composed with highly eroded crystalline limestone at the middle part of ridge slope at elev. 700-800 m a.s.l.
Terrestrial and lithophytic fern on very steep slopes. Common.
HLF 818 26 Dec. 2002.
Coll. Phan Ke Loc, L.Averyanov, Nguyen Anh Duc, To Van Thao, Mai Van Xinh, Nguyen Tien Vinh. Grant from Henry Luce Foundation.