1. Antitrichia Bridel, Muscol. Recent., suppl. 4: 136. 1818. • [Greek anti, opposite, and thrix, hair, alluding to endostome segments opposite exostome teeth].
Clayton C. Newberry
Plants large, in thick mats or deep wefts, yellow-green to dark green, glossy. Stems irregularly branched. Stem leaves ovate-lanceolate to cordate-ovate; base rounded to subcordate, slightly decurrent; margins revolute, serrate, serrulate, or denticulate; apex acute, acuminate, or abruptly acuminate; costa subpercurrent, with 2 or more shorter, supplementary costae at base; alar cells quadrate to transversely elongate, region extending nearly to costa and an equal distance distally; laminal cells smooth; medial cells uniformly linear-flexuose; apical cells oval-rhombic. Branch leaves similar, narrower, smaller, 2-3 × 1 mm; margins more strongly denticulate; apex narrower, flagelliform, smaller; costa weaker. Specialized asexual reproduction absent. Perigonia on secondary stems or sometimes on side branches, leaves deltoid-apiculate. Perichaetia on primary stems, leaves ecostate. Seta short. Capsule exserted, cylindric, oblong-cylindric, or oblong-ovoid; annulus scant or absent, adherent; operculum oblique-rostrate; exostome teeth subulate, trabeculate or papillose; endostome basal membrane absent, segments weakly developed, narrowly subulate, papillose.
Species 5 (2 in the flora): North America, South America, Europe, Asia, Africa, Atlantic Islands. The stems of Antitrichia are densely foliose and internally divided into a strong 4-6-layered cortex of incrassate cells and a medulla of loose, thin-walled cells. The branches are procumbent or pendent, somewhat plumose, and usually elongate, with deltate to subfoliose pseudoparaphyllia investing the branch buds; the central strand is rudimentary or absent. The stem leaves are concave and 2-3 × 1-1.5 mm; the basal laminal cells are rounded-quadrate to elliptic, in a region filling the basalmost angles and extending up most of the margins. The endostome segments are fragile, evanescent, and one-half to three-fourths the exostome teeth length.
