Schistidium cryptocarpum

Plants in cushions or low, sometimes extensive tufts, olivaceous or yellowish brown. Stems 0.8–2.5 cm, central strand distinct. Leaves erect or curved, rarely falcate, imbricate when dry, lanceolate to ovate-lanceolate, strongly keeled distally, (0.9–)1.4–2(–2.3) mm, 1-stratose; margins usually recurved to just before the apex, proximally often more broadly recurved on one side of leaf, distal 1/3 often plane, smooth, 1-stratose with 2-stratose sections; apices acute or sub-obtuse; costa excurrent as a denticulate, flexuose, usually strongly decurrent awn, often embracing part of the lamina, smooth; basal marginal cells short-rectangular, occasionally with transverse walls thicker than longitudinal walls; distal cells mainly short-rectangular or quadrate, 7–10(–11.5) µm wide, smooth, usually strongly sinuose. Sexual condition autoicous. Capsule orange-brown or reddish brown, campanulate, 0.5–0.6 mm; exothecial cells short-elongate or isodiametric, often more or less quadrate, thin-walled or slightly thickened, small trigones usually present; stomata present; operculum rostrate; peristome rudimentary, consisting of basal segments, or absent, yellowish, papillose. Spores 8–12 µm, verruculose.

Phenology: Capsules mature late spring to early summer.
Habitat: Shallow crevices and cavities on basalt cliffs
Elevation: low to moderate elevations (60-1200 m)

Greenland, N.W.T., Que., Alaska.

Discussion

The long, usually strongly decurrent awns and the campanulate capsules absent a distinct peristome separate Schistidium cryptocarpum from other arctic species of the geunus. Mogensen and Blom provided further details on this species. It should be confused only with S. flaccidum, a more southern species, which differs in having a mamillate rostrum and a cupulate capsule.

Selected References

None.

Lower Taxa