FLORA OF VIETNAM. Fam. Urticaceae. Pellaea sp. ?. N. Vietnam, prov. Cao Bang, distr. Nguyen Binh, municipality Ca Thanh. (N 22°44' E 105°50'). Primary semideciduous mixed forest along tops of. remnant karst limestone ridge at 1350-1400 m elev. Terrestrial herb. among shady rocks in wet places. Leaves from below brownish-purple. Common. No CBL 1307   13 April 1999. International Botanical Expedition of the U.S.A. National Geographic. Society (grant No 6300-98). . Collectors: P.K.Loc, P.H.Hoang, Averyanov L.