Monographs Details: Brachythecium
Authority: Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part Two: Orthotrichales to Polytrichales. Mem. New York Bot. Gard. 69 (2)
Description:Genus Description - Plants small and slender to moderately robust, yellow- to dark-green, in loose or dense, intertwining mats. Stems prostrate or rarely erect-ascending, irregularly to ± regularly pinnate, often tapered or stoloniform; branches straight or flexuose, ± tapered, sometimes hooked at ends. Leaves straight or occasionally secund, imbricate to wide-spreading when dry, generally more spreading when moist. Stem leaves generally concave, smooth to strongly biphcate, lanceolate to broadly ovate-cordate (generally ovate-lanceolate), gradually to abmptly narrowed to a short or long, straight or flexuose acumen (occasionally bent to 1 side), slightly to strongly decurrent; margins plane or recurved at base and sometimes beyond, occasionally well into the acumen, entire to serrate; costa very slender or stout, extending to the leaf middle or into the acumen, occasionally forked, sometimes ending as an inconspicuous dorsal spine; upper cells smooth, fusiform to linear, generally becoming lax toward the base; basal cells quadrate to linear, with ± pitted walls; alar cells little to distinctly differentiated as few to many, quadrate to rectangular, small to inflated cells. Dioicous or monoicous. Setae smooth or papillose; capsules erect to horizontal, oblong-ovoid to cylindric, generally curved; annulus ± differentiated; operculum conic to conic-rostrate (generally apiculate); exostome teeth lance-subulate, brown or red-brown, cross-striolate below, papillose at the tips, trabeculate; endostome ± papillose, the segments keeled, from a high basal membrane, the cilia well developed or rarely mdimentary or lacking. Spores smooth or papiUose.
Brachythecium rutabulum (Hedw.) B.S.G. is included in the key as it has been found in the western United States, Guatemala, and South America.) It has a rough seta, autoicous sexuality, and somewhat decurrent leaves.