Plants to 3 cm. Stem leaves erect, loosely-appressed when dry, oblong-lanceolate to ovate-lanceolate, 1.8--3 mm, broadly acute to obtuse; margins narrowly recurved-revolute to near apex, entire; distal laminal cells 7--12 µm wide, 1-stratose, smooth; basal laminal cells rectangular, not nodose in small leaves, long-rectangular and sometimes nodose in larger leaves. Sexual condition goniautoicous, perigonia numerous. Seta 2--3 mm. Capsule fully exserted; urn cylindric, 1.5--2.2 mm, slightly to distinctly 8-plicate for 1/2 length; stomates superficial; peristome single; endostome segments absent; exostome teeth 16, erect to spreading-reflexed when old and dry, smooth. Calyptra short-conic, naked. Spores 13--18 µm.

Seasonally wet rocks in small streams of dry montane forests; 1000--2000 m; Calif., Idaho, Oreg., Wash., Wyo. Restricted to w North America

This species is distinguished by having smooth leaf cells, smooth exostome, naked calyptra, and exserted, lightly-ribbed capsules. It is a distinct species, endemic to a small region in western North America, and is most closely related to O. laevigatum.