Plants in mats or patches, green, golden green, brown-green, or blackish, rarely with orange or red tinge. Stems slender, creeping, irregularly branched, sometimes unbranched, rarely regularly pinnate, branches (secondary and tertiary) spreading to erect, sometimes clustered, branching monopodial, older portion of primary stem often becoming stoloniferous; paraphyllia present or absent, unbranched or sometimes branched; pseudoparaphyllia foliose to linear or peglike; rhizoids few, usually arising from base of leaves. Stem and branch leaves usually similar, rarely differentiated. Stem leaves appressed to erect when dry, erect to erect-spreading or rarely squarrose when moist, ovate, ovate-lanceolate, or oblong, symmetric or sometimes asymmetric, not to distinctly plicate on either side of costa; margins plane to recurved, entire to serrate distally, limbidium absent or rarely present; apex broadly rounded, acute, or acuminate; ecostate to costa percurrent, sometimes 2-fid, occasionally sinuate distally; alar cells shorter than laminal cells, isodiametric to transversely elongate, region usually distinct; laminal cells isodiametric to elongate-rhomboidal or linear-fusiform, often prosenchymatous, sometimes obscure or opaque, smooth, papillose over lumen, or prorulose distally, walls thin to usually firm or thick, rarely pitted. Branch leaves often smaller; apex sometimes less acute; costa weaker. Specialized asexual reproduction rarely present, of clustered flagelliform branchlets in axils of distal branch leaves. Sexual condition dioicous or autoicous; perigonia budlike, on primary stems; perichaetial leaves on primary stems or rarely secondary branches, differentiated, opaque to translucent, apex longer, more acuminate than stem and branch leaves, costa short to excurrent. Seta elongate, thin, straight or somewhat curved, often twisted. Capsule erect to horizontal, long-exserted, oblong to pyriform, symmetric to asymmetric-curved, smooth; stomata absent or present, phaneropore; annulus absent or present; operculum conic, short-to long-rostrate; peristome double, perfect to variously reduced; exostome teeth lanceolate or linear-lanceolate, lamellae present, sometimes faint or absent, striolate to densely papillose; endostome basal membrane low to high, free or sometimes adherent to exostome at base, segments broad and keeled to linear, sometimes absent, cilia well developed to rudimentary or absent. Calyptra usually cucullate, small, fugacious, usually smooth. Spores smooth to variously roughened.
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