Thuidiaceae

Diagnosis: Plants small and slender, mostly green but occasionally golden, lax mats. Stems creeping, 1-2 pinnate, not frondose; paraphyllia few to relatively abundant, usually confined to the stems, filamentous, mostly unbranched. Stem and branch leaves typically strongly differentiated, stems leaves mostly broadly ovate, acuminate, seldom plicate, mostly short-decurrent or subauriculate; margins mostly crenulate-papillose, less often serrate to serrulate, often recurved at least below; costa single, usually strong but not filling the acumen; cells quadrate to short-rectangular, mostly pluripapillose, occasionally unipapillose, always on both surfaces, thin- to firm-walled, sometimes becoming more elongate in the acumen; alar cells not differentiated. Branch leaves mostly smaller than stem leaves, rarely ca. the same size, lanceolate to oblong to ovate, obtuse to rarely short-acuminate, usually concave, not plicate, not or slightly decurrent; margins mostly crenulate-papillose, less often serrate to serrulate, usually plane; costa single, weaker than in stem leaves, sometimes projecting as a spine at apex; cells mostly isodiametric, mostly pluripapillose, occasionally unipapillose, always on both surfaces, thin- to firm-walled; alar cells not differentiated. Seta elongate, smooth or roughened, reddish, capsules suberect to horizontal, rarely ± pendent, often asymmetric and arcuate, cylindric; operculum conic, often obliquely rostrate. Calyptra cucullate. Spores usually finely papillose.