Plants medium-sized. Stems 3-5 cm, regularly to irregularly pinnate, branches 0.3-0.7 cm. Stem leaves ovate, plicate, 1.1-1.8 mm; margins strongly revolute to near apex; costa double, distinct; medial laminal cells 30-40 × 4-5 µm.

Capsules mature Jul-Sep. Open sites, earth, rock faces, epiphytic on tree bases, logs in forests, commonly calcicole but not confined to calcareous substrates; low to high elevations; Greenland; Alta., B.C., Man., Nfld. and Labr., 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.; s South America; Europe; Asia; Antarctica.

Variety revolutum produces sporophytes in summer.