Nearly worldwide, mostly Northern Hemisphere.
Genera 4, species ca. 150 (3 genera, 36 species in the flora).
Mielichhoferiaceae includes species traditionally classified in Bryaceae but phylogenetically closer to Mniaceae. Mielichhoferiaceae also includes Pseudopohlia R. S. Williams of Mexico. The leaves are narrowly to broadly lanceolate (sometimes elliptic or, in tropical species of Epipterygium, obovate to spatulate), with elongate distal laminal cells. The leaf margins are generally serrate to serrulate; laminal cells along the margins are weakly or undifferentiated in Mielichhoferia and Pohlia, moderately differentiated in Epipterygium tozeri. The peristome is fundamentally diplolepidous and double with well-developed exostome and endostome, but is variously reduced in many species. The stems in this family often bear subfloral innovations below the gametangia.
Among species of Epipterygium, the North American E. tozeri is most similar to species of Pohlia, especially those of the Mniobryum group (the latter sometimes treated as a subgenus of Pohlia or as a separate genus).
The three genera of Mielichhoferiaceae in the flora area were almost universally classified in Bryaceae until C. J. Cox and T. A. J. Hedderson (2003) published a phylogenetic study showing that these genera are more closely related to Mniaceae than to Bryaceae. This conclusion has been repeatedly corroborated by additional data from all three genomic compartments: nuclear, chloroplast, and mitochondrial. Phylogenetic resolution of precise relationships among genera in Mielichhoferiaceae and Mniaceae in the strict sense has been more recalcitrant (Cox, pers. comm.).
|1||Peristome appearing single; endostome basal membranes rudimentary; perichaetia on short lateral branches.||Mielichhoferia|
|1||Peristome clearly double; endostome basal membranes low to high; perichaetia terminal, sometimes appearing lateral because of subfloral innovations||> 2|
|2||Stems not complanate-foliate; dorsal and lateral leaves not differentiated; marginal cells undifferentiated or slightly narrower than medial cells; leaves narrowly lanceolate to ovate-lanceolate.||Pohlia|
|2||Stems slightly complanate-foliate; dorsal leaves in 1-3 rows, smaller than lateral leaves; marginal cells weakly but distinctly differentiated from medial cells; leaves ovate- lanceolate to elliptic.||Epipterygium|