Plants large, in dense tufts or intermixed with other bryophytes, dark green, rufous proximally. Stems 1-3 cm, erect, simple or sparingly branched, tomentose proximally. Leaves laxly erect-appressed when dry, somewhat incurved and erect-spreading when moist, ovate-lanceolate, 0.8-1.2 mm; margins narrowly revolute basally, plane distally, serrulate throughout, teeth single; apex sometimes acuminate; costa subpercurrent to excurrent, abaxial surface smooth; laminal cell papillae 1, centric, on both sides (more prominent on adaxial side); basal cells subquadrate to quadrate, 15-20 × 8-10 µm; distal cells rectangular, 15-26 × 6-8 µm. Specialized asexual reproduction by slender brood branches in leaf axils. Sexual condition dioicous; perigonia somewhat gemmate. Sporophytes unknown.

Rocky cliffs, steep slopes, wet or dry sites; low to high elevations (0-2700 m); B.C., Nfld. and Labr. (Nfld.), Ont.; Alaska, Calif., Mont., Vt., Wash., Wyo.; e Asia (Japan, Korea).

Philonotis yezoana is easily recognized by its dark green color and centrally papillose laminal cells.