Trachybryum (Brotherus) W. B. Schofield, 1968.

Trachybryum is the only species of a genus endemic to the west coast of North America. It is a segregate from the pleurocarpous genus Homalothecium with which it shares the features of plicate leaves and a strong costa. Trachybryum was segregated from Homalothecium on the basis of the elongate (not quadrate) cells of the alar region. Additional differential characters include the plumose growth pattern from a somewhat upwardly directed main stem axis. The leaves are broadly ovate rather than variously lanceolate as in Homalothecium, and the median cells are very strongly porose. Trachybryum megaptilum is one of several species of moss that have been called "pseudautoicous" on the basis of the presence of dwarf males in the axils of leaves very near the perichaetia. Such dwarf males arise from separate spores that have fallen into those leaf axils and grown into structures consisting of nothing more than a very short stem without vegetative leaves but with perigonial leaves surrounding a group of antheridia and paraphyses.
see Keys to Homalothecium, Hylocomium Etc.

Species included:
Trachybryum megaptilum (Sullivant) W. B. Schofield