Plants with shoots 10 15 × 0.6 0.9 mm, forming mats, green to brown or blackish. Stems 100 180 µm, sparingly branched, the branches terminal, occasionally intercalary. Leaves remote to slightly overlapping, nearly flat, ovate quadrate, slightly longer than wide, 370 600 x 320 500 µm, 2-lobed 1/3 1/2 , with a narrow sinus and subacute to acute lobes ending in 1 2 single cells; lateral leaf margins often with a small tooth; leaf cells subquadrate, 22 28 µm, walls slightly thickened, often brownish; trigones not developed; oil bodies 3 8 per cell, ovoid or spherical 4 6 × 5 8 µm, smooth or slightly granular. Underleaves absent or vestigial, of small cilia or slime papillae. Specialized asexual propagation usually absent or rarely by gemmae on margins of leaf lobes, angular, 14 18 µm, 2 celled, brown. Plants usually sterile. Gynoecia with bracts similar to leaves in shape, larger; perianth rarely produced, not easily detached, inflated, clavate, the mouth dentate.

Igneous rock that are perhaps copper bearing, where they may occur with other rare species such as Cephaloziella massalongoi or Gymnomitrion concinnatum; w Greenland; Alaska, Maine, Tenn.; Europe.