Plants with shoots 5 10 × 0.8 1.3 mm, prostrate with ascending tips, in small flat patches or mats of suberect plants, green to brown or reddish brown, often purplish beneath. Stems 275 325 µm in diameter; branches few, intercalary; rhizoids dense, scattered along stem, colorless, occasionally reddish tinged. Leaves distant to contiguous on lower stem to imbricate on distal stem, slightly concave, orbicular to reniform, 450 575 × 750 900 µm, entire to shallowly retuse, or 2-lobed with sinus less than 1/5 leaf length, forming blunt, rounded, entire lobes; median leaf cells 24 30 × 20 25 µm, marginal cells smaller, 18 25 µm; cuticle smooth; cell walls thin, trigones large to bulging; oil bodies 2 3 per cell, ovoid to ellipsoid, large, 7 15 × 6 10 µm, granular opaque. Underleaves vestigial to subulate or lanceolate, often connate to leaf on one side, largest near stem apex. Sexual condition paroicous. Androecia beneath gynoecia; bracts 2 4 pairs, similar to leaves, larger, concave, entire to emarginate or crispate. Gynoecia terminal, fleshy; bracts larger and broader than leaves, reniform, ca. 700 × 1000 µm, exceeding the perianth, shallowly 2--3-lobed; bracteole large, to 650 µm, sometimes lobed; perianth conical, 250 300 µm, shorter than bracts, mouth crenulate denticulate; perigynium fleshy, 500 800 µm, densely rhizoidous, continuous with upright stem or at distinct angle to prostrate stem. Sporophyte capsule subglobose, brown; elaters 2 spiral. Spores 14 16 µm, slightly verruculose.

Thin soil over rock outcrops or on damp peaty soil along streams, Arctic alpine; n, nw and w Greenland; Alta., B.C., Nfld, N.S., Que.; Alaska, Colo., Conn., Calif., Maine, Mass., Mont., N.H., N.J., Ohio, Oreg., Pa., Utah, Wash., Wyo.; Europe.

A varietal name, Nardia geoscyphus var. bifida R. M. Schuster, has been proposed for plants with all leaves emarginate or shallowly 2-lobed with rounded lobes and decurrent leaf bases. This variety is known only from specimens collected in ne Greenland from soil in rock caves. Variation in leaf shape may have been induced by unique environmental conditions.