Plants 1--12.5 cm, usually longer than 3 cm. Stem leaves erect-appressed when dry, narrowly lanceolate to ovate-lanceolate, 2--4.5 mm, sharply to slenderly acute; margins recurved to narrowly revolute to near apex, entire; distal laminal cells 6--13 µm wide, 1-stratose, with 1--2 small, conical or low, forked papillae per cell; basal laminal cells elongate, thick-walled and nodose to rectangular and thin-walled. Sexual condition goniautoicous. Seta less than 1.8 mm. Capsule immersed, emergent or slightly exserted, usually ± 1/3 emergent; urn globose ovate, ovate-oblong, or short-oblong, 1.3--1.8 mm, lightly or distinctly 8-ribbed for 1/2--2/3 the length; stomates superficial; peristome single, rarely double; endostome segments lacking or rarely 8 and rudimentary; smooth or roughened; exostome teeth 16, erect or sometimes spreading-recurved when old; smooth, scattered-papillose to coarsely papillose-granulate. Calyptra oblong, hairy or rarely naked, hairs finely papillose. Spores 13--21 µm.

Non-calcareous boulders and cliff faces in mesic areas of pine, spruce-fir or aspen forests, usually at higher elevations, rarely found in sterile condition at the base of trees, frequently collected in subalpine shaded situations; 100--3000 m; Greenland; Alta., B.C., N.W.T., Nun., Ont., Yukon; Alaska, Ariz., Calif., Colo., Idaho, Mont., Nev., N.Mex., Oreg., S.Dak., Utah, Wash., Wyo.; South America ; Europe; Asia; n and e Africa; Asia (Japan); Atlantic Islands (Canary Islands); Pacific Islands (New Zealand); Australia.

In typical form, O. rupestre is characterized as follows: (1) plants much branched in loose tufts; (2) leaves lanceolate, apex narrowly and bluntly acute; (3) basal cells elongate, thick-walled, and nodose, yellowish in older leaves; (4) capsule oblong, emergent, 8-ribbed 1/2 the length when old and dry, smooth or slightly 8-ribbed when mature; (5) exostome of 16 teeth, coarsely papillose; and (6) calyptra with abundant spinulose, papillose hairs, some of which extend over the beak.