Plants: in thin mats, yellow-green. Stems: to 5 cm, subpinnate, branches terete-foliate. Leaves: erect to spreading, oblong-lanceolate, slightly plicate, 1.2–2 mm; margins plane, subentire proximally, ± serrulate distally; apex slender acuminate; ecostate or costa double, short; alar region ± abruptly differentiated, 1-stratose, not reaching costa. Sexual: condition autoicous. Seta: yellow, 0.5–1.5 cm. Capsule: cylindric, to 1.4–2 mm; annulus 3- or 4-seriate, persistent; operculum bluntly short-rostrate; exostome teeth reddish, external surface densely papillose throughout, not perforate; endostome segments densely papillose. Spores: 16–21 µm.
Bark at base of hardwood trees, logs, stumps, rock. low to moderate elevations. N.B., Nfld. and Labr. (Nfld.), Ga., Ill., Ind., Maine, Mass., N.J., N.Y., N.C., Ohio, Pa., Va., W.Va., Wis.
Entodon brevisetus is an uncommon but widely dispersed species recognizable by its terete-foliate plants with slenderly acuminate leaves. The setae are yellow and the exostome teeth are densely papillose throughout. The endostome is sometimes adherent to the exostome teeth.