Plants: in dense mats, golden brown to reddish. Stems: to 8 cm, irregularly to ± regularly pinnate, branches terete-foliate. Leaves: erect, ovate-lanceolate, oblong-ovate, or broadly ovate, (0.8–)1–1.5 mm; margins plane or slightly recurved proximally, entire proximally, usually serrulate distally; apex acute or sometimes mucronate, rarely narrowly obtuse; costa double, short, often ending 1/4–1/2 leaf length; alar region ± abruptly differentiated, 1-stratose, reaching costa or not. Sexual: condition autoicous. Seta: reddish, 1–2 cm. Capsule: long-cylindric, 2.5–4 mm; annulus 3–5-seriate, deciduous; operculum bluntly long-conic, slightly oblique; exostome teeth yellow-brown, external surface densely papillose, not perforate; endostome segments smooth to papillose. Spores: 10–12 µm, smooth to finely papillose.
Logs, rock, exposed, dry habitats. moderate elevations. Ariz., N.Mex., Tex., Mexico, West Indies, South America.
Entodon beyrichii is a very common species in the drier habitats of Mexico, but barely reaches the United States. The species often grows in very dry, exposed habitats and then the seta can become bleached and appear not to be red. The papillose exostome teeth and smooth to papillose endostome segments aid in identification.