Plants green, often pigmented with reddish purple blotches above, purplish red along the undulate, ascending margins and below; branching dichotomous, ventral intercalary branches infrequent. Thalli 10 30 ´ 4 6 mm; epidermis faintly areolate, cells 30 ´ 25 µm with thin walls and no trigones, oil cells few, scattered; air pores surrounded by 3 4 tiers of 6 8 scarcely differentiated cells; ventral scales large, purple with scattered oil cells; appendages 1 2, white, lanceolate to acuminate. Sexual condition paroecious or autoecious, androecia posterior to gynoecial stalks or on separate branches, ovate, with variable number of papillae, or forming dorsal streaks of papillae; gynoecia terminal on main thalli; stalks purplish, 1.5 2.5 cm with hairlike scales at bases and apices; carpocephala 3 4 mm across, conical with low tubercules above and 3 4 short lobes directed downward; pseudoperianths pleated, often purplish, of 12 or more segments with connate apices. Sporophyte capsules purple; spores deep purple, 80 100 µm; elaters purple, 2 spiral, 100 150 µm.

Capsules mature July--Aug. Damp, mossy soil, frequently calcareous, arctic alpine; Alta., B.C.; Alaska, Colo., Mont., Oreg., Utah, Wash., Wyo.; Mexico; South America (Colombia); Europe.

The purple spores and elaters of this species are distinctive and when fruiting it can be readily separated from other species in the flora on that basis.