Plants 4--12 mm. Stem leaves imbricate, erect-appressed when dry, ovate to ovate-oblong, concave, 2--2.8 mm; rounded to obtuse; margins involute, entire; distal laminal cells 7--12 µm wide, 1-stratose, with 2--3 conical papillae; basal laminal cells elongate-rectangular, non-nodose. Sexual condition dioicous. Seta ± 0.5 mm. Capsule immersed; urn oblong, 1.8 mm; moderately 8-ribbed when dry; stomates superficial, in one row at distal end of capsule; peristome none. Calyptra obscurely plicate, naked, papillose. Spores 18--20 µm.

Bark of deciduous trees; 0--200 m; Nfld.; Europe; Asia (Japan).

This species differs from O. obtusifolium (a species with similar appearance) by having leaves with involute margins, cells with 2--3 papillae, and immersed capsules with no peristome, while O. obtusifolium has leaves with erect margins, unipapillose cells, and emergent capsules with a double peristome. Orthotrichum gymnostomum is rare in North America, restricted to the coastal areas of Newfoundland.