Shoots erect, determinate, 6--10 cm, clustered to rarely shortly decumbent, decumbent portion to 1 cm; leaves in mature distal portion markedly smaller than leaves in juvenile proximal portion; annual constrictions absent; juvenile growth erect. Leaves ascending to spreading (juvenile portion) or ascending to appressed (mature portion), green to yellow green, not lustrous; leaves in juvenile portion narrowly triangular, 4--6 mm, widest at base; leaves in mature portion narrowly triangular, 2--3.5 mm; margins entire or with occasional papillae; stomates present on both surfaces, numerous (35--60 per 1/2 leaf) on adaxial surface. Gemmiferous branchlets produced throughout mature portion; gemmae 3--4 X 2.5--3.5 mm; lateral leaves 0.5--1 mm wide, narrowly acute. Spores 29--35 µm.

On damp, acidic, igneous rocks in alpine zone or exposed cliffs and talus slopes elsewhere; 800--2300 m, lower (600--1200 m) along coast of Atlantic Ocean and Lake Superior; Greenland; St. Pierre and Miquelon; Nfld., N.S., Ont., Que.; Ga., Maine, Mass., Mich., Minn., N.H., N.Y., N.C., S.C., Tenn., Vt., Va.; possibly Europe.