Hypnum concinnum De Notaris, Mem. Reale Accad. Sci. Torino 39: 220. 1836; Entodon orthocarpus (Bridel) Lindberg

Plants in loose or occasionally dense mats, yellow-green to brownish yellow. Stems to 10 cm, spreading to ascending, pinnate, branches terete-foliate. Leaves erect, oblong-ovate, 1.5-2 mm (branch leaves 1-1.3 mm); margins incurved distally, entire; apex rounded-obtuse; ecostate or costa double, short; alar region abruptly differentiated, 2- or 3-stratose, not reaching costa. Sexual condition dioicous. [Seta reddish, 1.3-2.5 cm. Capsule cylindric, 2-2.5 mm; annulus 2-or 3-seriate, persistent; operculum conic, obliquely short-rostrate; exostome teeth reddish, external surface cross striolate proximally, obliquely to vertically striolate mid tooth, finely papillose to smooth apically, not perforate; endostome segments smooth. Spores 11-14 µm].

Soil, rock, calcareous areas; low to high elevations; Alta., B.C., N.B., Nfld. and Labr. (Nfld.), N.W.T., Yukon; Alaska, Colo., N.Mex., Tenn.; South America (Ecuador); Eurasia; Pacific Islands (Papua New Guinea).

Entodon concinnus is the most distinctive species in the genus. It is the only dioicous species, the branch and stem leaves are fairly well differentiated (in size), and the alar cells are multistratose (rather than 1-stratose). Sporophytes are unknown in North America; the description here is from European material.