Bryum marratii Hooker & Wilson in W. M. Wilson, Bryol. Brit., 434, plate 32, fig. b. 1855

Plants in dense or open turfs, yellow-green to yellow-brown. Stems 0.5-2 cm, fertile stems comose, innovations evenly foliate. Leaves yellow-green to green distally, brown with age, crowded, somewhat contorted to shrunken when dry, ovate, concave, (0.5-)1-2 mm, not much enlarged toward stem apex; base green, not decurrent; margins plane, limbidium absent, or rarely in 1 weak row, 1-stratose; apex broadly acute to obtuse; costa not reaching apex, apiculus absent; proximal laminal cells irregularly rectangular to rhomboidal, 3-4:1; medial and distal cells 18-25 µm wide, 2-3:1, walls thin. Specialized asexual reproduction absent. Sexual condition autoicous. Seta red-purple, 2-4(-5) cm, stout, somewhat flexuose. Capsule yellow-brown to red-brown, pyriform, symmetric, 2-3 mm, mouth yellow-brown to red-brown; operculum long-conic; peristome reduced; exostome teeth red-brown basally, yellow distally, lamellae straight, pores absent near base along mid line; endostome weakly adherent to exostome, basal membrane 1/2 exostome height, segments narrowly perforate, cilia absent or rudimentary. Spores (30-)32-40 µm, yellow.

Capsules mature Jul-Sep. Moist soil; low to moderate elevations (0-1000 m); Greenland; Alta.; N.Dak., Wash.; nw Europe.

Ptychostomum marratii is a distinctive arctic-boreal species with oblong, more or less obtuse green leaves that lack a limbidium. The proximal laminal cells are somewhat bulging. The species is found typically along the coasts of northern Europe. Two of the three North American collections are from interior regions.