Bryobrittonia R. S. Williams, Bull. New York Bot. Gard. 2(6): 115. 1901.
Plants medium sized, gregarious. Stems rarely branched; central strand absent or weakly differentiated. Leaves oblong, elliptic or narrowly obovate; apex broadly acute, mucronate; margins plane to weakly incurved, crenulate distally, entire proximally; costae subpercurrent, smooth; distal laminal cells more or less rhomboidal, bulging on both exposed surfaces, but stronger adaxially; basal cells long-rectangular; marginal cells sometimes longer proximally forming a very weak border. Sexual condition dioicous. Seta very long, smooth, reddish brown to black. Capsule long-exserted, erect, furrowed; peristomate, stomata numerous; peristome double, exostome teeth long, narrow; endostome with basal membrane, segments filiform, almost as long as teeth, papillose. Operculum long conic-rostrate. Calyptra generally smooth, erose or lacerate at base. Spores small, round.
Species 1: Greenland; n North America, n Asia.
Found on open, calcareous soil across the northern reaches of the flora area, Bryobrittonia closely resembles Encalypta in its habitat preferences and growth form, and is only separated by microscopic characters. Fruiting specimens produce the large, brownish calyptra diagnostic of the family, but perhaps associated with dioicy, sporophytes are rare. Bryobrittonia can be separated from Encalypta, the only other genus in the family, by bulging distal laminal cells and crenulate distal leaf margins.