Platylomella

Plants small to somewhat large, dark green to blackish with yellowish green shoot apices. Stems fine, prostrate, irregularly branched or subpinnate; hyalodermis absent, central strand present; paraphyllia present, filiform; rhizoids basal or sometimes adventitious distally on decumbent shoots, forming tomentum, slightly branched, smooth; axillary hair distal cells 1 or 2, hyaline. Stem leaves erect-spreading, straight or incurved, cordate-ovate to ovate-lanceolate, not plicate, 0.5–1.5 mm; base not decurrent; margins plane, serrulate distally or to base, sometimes entire, limbidia conspicuous or sometimes inconspicuous, 2–4-stratose, cells incrassate; apex gradually or abruptly acuminate, sometimes apiculate, tips often obtuse; costa single, strong, percurrent to short-excurrent, usually confluent distally with limbidia; alar cells undifferentiated; basal laminal cells rectangular or oblong-hexagonal; distal cells short-rhomboidal to oblong-hexagonal, 6–12 × 15–40 µm. Branch leaves similar, slightly smaller and narrower. Sexual condition autoicous. Capsule horizontal to cernuous, oblong-cylindric, asymmetric, sometimes arcuate; peristome hypnoid; exostome margins dentate; endostome cilia appendiculate. Spores 12–17(–25) µm.

Distribution

c, e North America.

Discussion

Species 1.

Platylomella has previously been included in Sciaromium (Mitten) Mitten, a synonym of Echinodium Juratzka (S. P. Churchill 1986).

Selected References

Andrews, A. L. 1945. Taxonomic notes. IV. Sciaromium lescurii. Bryologist 48: 100–103.

Ochyra, R. 1987. A revision of the moss genus Sciaromium (Mitt.) Mitt. III. The section Platyloma Broth. J. Hattori Bot. Lab. 63: 107–132.

Lower Taxa

Platylomella lescurii