Ptychomitrium

Plants small to robust, tufted or caspitose, dark green to blackish. Stems erect or repent. Leaves erect to crispate when dry, margins entire to serrulate or serrate; medial cells smooth or slightly papillose. Specialized asexual reproduction rare, by 1-seriate gemmae on branched axillary filaments. Seta straight. Capsule ovoid to cylindric, symmetric or slightly curved, smooth to wrinkled or ribbed when dry. Calyptra mitrate, more or less plicate, lobed proximally. Spores smooth to papillose.

Distribution

Nearly worldwide, mostly in temperate regions.

Discussion

Species 40–50 (5 in the flora).

Excluded Species:

Glyphomitrium canadense Mitten

This taxon was included for western Canada by G. N. Jones (1933), but was excluded from North America by H. A. Crum (1972) and L. E. Anderson et al. (1990). Crum considered Glyphomitrium canadense to be a synonym of the British G. daviesii (Withering) Bridel and suggested that the specimen on which Mitten based the name came from Great Britain.

Selected References

Cao, T. and D. H. Vitt. 1994. North American–East Asian similarities in the genus Ptychomitrium (Bryopsida). Bryologist 97: 34–41.

Lower Taxa

Ptychomitrium drummondii, Ptychomitrium gardneri, Ptychomitrium incurvum, Ptychomitrium serratum, Ptychomitrium sinense

Key

1	Leaves coarsely serrate distally	> 2
1	Leaves entire or obscurely irregularly serrulate distally	> 3
2	Leaves slenderly long-acuminate, 4-6 mm; basal leaf margins broadly recurved on one or both sides; calyptra deeply lobed proximally, lobes half length of calyptra.	Ptychomitrium gardneri
2	Leaves broadly acuminate, 3-4 mm; basal leaf margins plane and erect or irregularly narrowly recurved on one side proximally; calyptra shallowly lobed proximally, lobes less than 1/2 length of calyptra.	Ptychomitrium serratum
3	Plants dull, mostly corticolous; leaves straight or slightly contorted but not crispate when dry, margins mostly obscurely serrulate distally.	Ptychomitrium drummondii
3	Plants glossy, mostly on rock; leaves crispate when dry, margins entire	> 4
4	Longest leaves mostly 2.5-4 mm.	Ptychomitrium sinense
4	Longest leaves mostly 2 mm.	Ptychomitrium incurvum