Bryum weigelii Sprengel, Mant. Prim. Fl. Hal., 55. 1807

Plants in loose low open turfs, green or rarely pinkish red. Stems 2-4(-6) cm, fertile stems comose, innovations evenly foliate. Leaves green, yellow-green, or rarely red or pink, distant, strongly contorted to shrunken when dry, ovate-lanceolate, flat, 1-3 mm, not much enlarged toward stem apex; base usually green, strongly and broadly decurrent, decurrencies almost reaching next more proximal leaf; margins revolute proximally, plane distally, limbidium weak, in 1 (or 2) rows; apex acute; costa not reaching apex to short-excurrent, awn slender; proximal laminal cells hexagonal to rectangular, 3-4:1; medial and distal cells 18-25(-30) µm wide, 2-3:1, walls thin. Specialized asexual reproduction absent. Sexual condition dioicous. Seta red-brown, 2-4 cm, slender, straight to somewhat flexuose. Capsule brown, turbinate to pyriform, symmetric, 3-4 mm, mouth yellow; operculum convex, apiculate; peristome well developed; exostome teeth yellow basally, hyaline distally, lamellae straight, pores absent near base along mid line; endostome not adherent to exostome, basal membrane 1/2 exostome height, segments broadly perforate, cilia well developed, long, appendiculate. Spores (12-)14-18 µm, yellow or green.

Capsules mature Jun-Aug. Wet soil, wetlands, along streams; low to high elevations (0-3500 m); Greenland; Alta., B.C., Man., Nfld. and Labr., N.W.T., N.S., Nunavut, Ont., P.E.I., Que., Sask., Yukon; Alaska, Ariz., Calif., Colo., Conn., Idaho, Maine, Mass., Mich., Minn., Mont., Nev., N.H., N.Dak., Ohio, Oreg., Pa., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; South America; Eurasia; Africa; Pacific Islands (New Zealand); Australia.

Ptychostomum weigelii is a common arctic-boreal to north-temperate species in wet sites, easily identified by the broad, long marginal decurrencies of the leaves that nearly reach to the next leaf. Leaves of the similar P. cyclophyllum and P. turbinatum are either not decurrent or only produce short, very slender decurrencies. Plants of P. weigelii from Colorado are pinkish red.