Plants reddish brown to black. Leaves weakly spreading, straight or sometimes secund, narrowly lanceolate, widest proximally, apex symmetric; costa absent; leaf margins entire; basal laminal cells rectangular, marginal cells not different in shape, walls thickened, pitted, sinuose; medial laminal cells rounded-quadrate to ovate, 1-stratose entirely or sometimes 2-stratose in patches distally, lumens rounded; laminal papillae low, large, brown to whitish, mainly medial. Sexual condition apparently dioicous, possibly cladautoicous; perichaetial leaves differentiated, convolute-sheathing. Spores 12-20 µm.
Acidic rock in snow beds; low to moderate elevations; B.C.; Alaska; nw Europe.
Andreaea sinuosa is uncommon, and is distinguished from the similar A. rupestris by the symmetric and often rounded leaf apex and sinuose basal laminal cells.