Bryum wrightii Sullivant, Proc. Amer. Acad. Arts 4: 278. 1859

Plants in dense or open turfs, red-green or red-brown. Stems0.5-1(-2) cm, fertile stems comose, innovations evenly foliate. Leaves yellow-green to red-green, distant proximally, crowded distally, somewhat contorted to shrunken when dry, ovate, concave, 0.5- 2 mm, not enlarged toward stem apex; base green, not decurrent; margins revolute proximally, limbidium strong, in 2 or 3 rows; apex acute; costa percurrent to short-excurrent, awn absent; proximal laminal cells long-rectangular, 3-5:1; medial and distal cells 18-25 µm wide, 2-3:1, walls thin. Specialized asexual reproduction absent. Sexual condition synoicous. Seta red-brown, 1-3 cm, slender, straight to somewhat flexuose. Capsule yellow-red, red, or red-brown, often shiny, broadly ovate to pyriform, symmetric, 2-3 mm, mouth yellow-red; operculum short-conic, smooth or weakly apiculate; peristome reduced; exostome teeth yellow proximally, hyaline distally, lamellae somewhat curved proximally, pores absent; endostome not or weakly adherent to exostome, basal membrane low to rudimentary, segments very short, cilia absent. Spores 18-20(-22) µm, yellow.

Capsules mature Jul-Aug. Damp calcareous soil, silt, tundra; low to moderate elevations (0-1500 m); Greenland; Nfld. and Labr. (Labr.), N.W.T., Nunavut, Que., Yukon; Alaska; Eurasia.

Ptychostomum wrightii is a small arctic species with distinctive capsules that are somewhat inflated, shiny red, and ovate to pyriform, and a poorly developed fragile endostome. The stems are sparsely radiculose; the costal awns are smooth. Capsules are needed for identification.