Plants with shoots 10 30 × 1.2 1.8 mm, prostrate with ascending apices, light green with reddish lower stem and leaf bases. Stems soft, ca. 300 µm in diameter, branches few, intercalary; rhizoids numerous, dense at leaf bases with few scattered along stems, colorless, occasionally slightly purplish tinged. Leaves somewhat quadrate, wider than long, 0.6 0.8 × 0.8 1 mm, uniformly emarginate to 2-lobed up to 1/3 the leaf length, with triangular, blunt lobes; median leaf cells 35 40 × 32 36 µm, marginal cells smaller, 30 33 µm; cuticle smooth, walls thin with bulging trigones; oil bodies 2 3 per cell, ovoid to ellipsoid, 6 7 × 14 16 µm, grayish opaque. Underleaves present throughout, spreading, lanceolate with reddish bases. Sexual condition paroicous. Androecia beneath perianth; bracts undulate crispate, ca. 1 1/2 times larger than leaves, 2-lobed ca. 1/2; base slightly concave. Gynoecia form a terminal fleshy head, continuous with stem in upright plants, forming an angle with stem in prostrate plants; bracts wide, 700 900 × 1100 1400 µm, 2-lobed about 1/2 their length, crispate; bracteole lanceolate, large, to 900 µm; perianth short, 400 500 µm, conical, contracted to crenulate mouth; perigynium fleshy, 1000 1200 µm, elaters 2 spiral. Spores 20 24 µm, slightly granulate, brownish.

Moist to wet humus or loam in bogs or along streams, Arctic alpine; B.C., Nfld., N.S.; Maine, N.H., N.Y., Wash., Wyo.; Europe.

Nardia insecta is similar to and perhaps derived from N. geoscyphus and was at one time considered a form or variety of the latter. The chromosome number of N. geoscyphus is n=18; it is n=36 in N. insecta, a slightly more robust plant of similar habitat. Leaves of N. insecta are almost all 2-lobed to about 1/3 their length and cells are slightly larger with coarser trigones.