Ptychostomum intermedium

Plants in dense or open turfs, green or yellow-green. Stems 1–2 (–3) cm, comose, innovations comose or somewhat elongate and evenly foliate; often strongly radiculose. Leaves green, twisted to contorted when dry, ovatelanceolate, flat to weakly concave, (1–) 1.5–2 (–3) mm, not much enlarged toward stem apex; base weakly decurrent; margins revolute to mid leaf or beyond, limbidium weak to strong, in 1–2 (–3) rows; apex acuminate; costa long-excurrent, awn ± smooth; proximal laminal cells 3–4: 1, same width or sometimes wider than more distal cells; medial and distal cells rhomboidal, 12–20 µm wide, 3–4: 1, walls usually thin to firm, never oblique to costa. Specialized asexual reproduction absent. Sexual condition synoicous. Seta 1–2 (–3) cm. Capsule brown, elongate-pyriform, asymmetric, somewhat curved, 2–4 mm, mouth oblique, 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, 1/2 exostome height, segments with narrowly ovate perforations, cilia long, nodose. Spores (18–) 20–26 (–30) µm, finely papillose, pale-yellow or green.

Phenology: Capsules mature Jun–Sep.
Habitat: Wet soil, boreal-temperate areas
Elevation: moderate elevations (1000-1500 m)

Greenland, Alta., B.C., Man., Ont., Sask., Eurasia

Discussion

Although material of Ptychostomum intermedium was not confirmed by A. L. Andrews (1935), a few collections from the southern portion of the boreal zone in Canada can be assigned to this species based on asymmetric capsules, synoicous sexual condition, nodulose cilia, and correct spore size. Otherwise this species is similar to P. creberrimum and P. lonchocaulon. The costal awns are pigmented. Mature capsules are needed for identification.

Selected References

None.

Lower Taxa