Physcomitrium collenchymatum

Illustrator: Patricia M. Eckel

Copyright: Flora of North America Association

Plants light green or yellowish green. Stems 2–4(–5) mm. Leaves obovate to ovate-lanceolate, concave, distal leaves 1.2–2 mm; margins toothed distally; costa percurrent to subpercurrent. Specialized asexual reproduction as tubers occasionally present. Seta 2–3 mm. Capsule exserted, 0.5–1.2 mm, ovoid to hemispheric when young, cupulate following dehiscence of operculum, and usually becoming shallow and wide-mouthed with age; neck short, indistinct; exothecial cells irregular rounded-hexagonal, often with curved walls, sometimes collenchymatous (apparently only on young capsules); suboral cells weakly differentiated, usually consisting of 2–6 rows of irregularly isodiametric cells. Spores 24–38 µm, spiculose or papillose.

Phenology: Capsules mature late fall–spring.
Habitat: Wet soil in disturbed places
Elevation: low to moderate elevations

Distribution

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N.S., Fla., Kans., La., Miss., Tenn.

Discussion

The small size combined with the wide-mouthed and shallow mature capsules distinguish this taxon from other species of Physcomitrium. The collenchymatous exothecial cells that are associated with the name of this species are most common in maturing capsules and rarely present in mature capsules (R. R. Ireland 1982; H. A. Crum and L. E. Anderson 1981).

Selected References

Crum, H. A. and L. E. Anderson. 1964. Notes on Physcomitrium collenchymatum. Bryologist 67: 350–355.

Lower Taxa

None.