Ptychostomum longisetum

Plants in dense or open turfs, green or yellow-green. Stems 1–2(–3) cm, comose, innovations comose or somewhat elongate and evenly foliate; not strongly radiculose. Leaves green or yellow-green, twisted to contorted when dry, ovate to broadly ovate-lanceolate, weakly concave, 1–2(–3) mm, enlarged toward stem apex; base not or weakly decurrent; margins revolute to mid leaf or beyond, limbidium strong, in 2 or 3 rows; apex acute; costa short-excurrent, awn recurved, denticulate; proximal laminal cells 3–4:1, same width or sometimes wider than more distal cells; medial and distal cells rhomboidal, 12–18 µm wide, 2–3:1, walls usually thin to firm. Specialized asexual reproduction absent. Sexual condition synoicous. Seta 3–6(–8) cm. Capsule brown, elongate-pyriform, symmetric, 2–4 mm, mouth yellow; operculum conic, apiculate; peristome well developed; exostome teeth yellow basally, hyaline distally, lamellae usually straight mid tooth, pores absent along mid line; endostome not adherent to exostome, basal membrane high, less than 1/2 exostome height, segments with broadly ovate perforations, cilia short, rudimentary. Spores variable in size, (38–)40–50 µm, finely papillose, pale yellow-brown or green.

Phenology: Capsules mature Jun–Sep.
Habitat: Damp soil in wetlands
Elevation: low to moderate elevations (0-600 m)

Greenland, Nfld. and Labr., N.W.T., Nunavut, Yukon, Alaska, Eurasia.

Discussion

Ptychostomum longisetum is a circumpolar arctic-boreal species related to P. inclinatum. Gametophytically it is similar to P. intermedium and P. salinum but differs in the extremely long seta and very large spores.

Selected References

None.

Lower Taxa