Plants medium sized to slender, 3--5 cm, regularly to irregularly pinnate, with branches 0.3--0.7 cm. Leaves of stem ovate, tapering to apex, 1.1--1.8 × 0.4--0.6 mm, margins usually strongly revolute to near apex; median cells 30--40 × 4--5 µm, costa double, usually apparent.

Sporophytes produced summer, capsules mature July--September. Open sites, earth and rock faces, epiphytic on tree bases, logs in forest, commonly a calcicole but not confined to calcareous substrata; 0--4000 m; Greenland; Alta., B.C., Man., Nfld., N.W.T., N.S., Nunavut, Ont., Que., Sask., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., S.Dak., Tex., Utah, Wash., Wyo.; South America (Chile); Europe; Asia; Antarctica.