Nearly worldwide, mostly in temperate regions.
Genera 3, species ca. 80 (2 genera, 6 species in the flora).
The acrocarpous habit, thickened and often serrate leaf margins, smooth or nearly so leaf cells, single peristome, and mitrate, basally lobed, and sometimes plicate calyptra make Ptychomitriaceae recognizable. The family has been included in Grimmiaceae by some authors, e.g., S. P. Churchill (1981), E. Lawton (1971), and A. Noguchi and Z. Iwatsuki (1987+, part 2), but it is recognized as a distinct haplolepideous family by, e.g., H. A. Crum and L. E. Anderson (1981) and D. H. Vitt (1982).
|1||Plants delicate, very small; leaves linear above base, entire, commonly circinate when dry; seta flexuous; calyptra smooth.||Campylostelium|
|1||Plants coarse, small to robust; leaves acuminate above base, entire to serrulate or serrate, sometimes crispate but not circinate; seta straight; calyptra plicate.||Ptychomitrium|