Family: Calymperaceae

Diagnosis: Plants erect (rarely prostrate and with erect-ascending branches), with simple to highly forked stems in loose to dense mats or cushions. Leaves sometimes dimorphic (gemmiferous and nongemmiferous), straight to crispate or variously contorted or twisted when dry; intramarginal files of differentiated cells (teniolae) present or lacking; costa single and strong; basal part mostly sheathing and with evident shoulders, including usually conspicuous fields of enlarged, hyaline, externall and internally posrose cells (cancellinae); upper part of leaf shorter to many times longer than lower lamina, its margins mostly variously thickened or bordered, or both, but rarely undifferentiated, mostly toothed at least in part; cells of upper lamina isodiametric to vertically or transversely elongate, smooth to bulging to mammillose to uni- or pluripapillose; gemmae frequently present on leaves in Calymperes, less common in Syrrhopodon. Setae smooth, mostly elongate; capsules cylindrical, mostly exerted but rarely immersed; operculum rostrate; peristome single or lacking, often vestigial, the teeth variously papillose externally, mostly smooth internally. Calyptra naked, smooth or papillose, cucullate and deciduous or rarely conical-mitrate (Syrrhopodon), or clasping the seta below the capsule and persistent (Calymperes). Spores mostly spherical and finely papillose.

Notes: W. D. Reese has monographed the family for the New World: 1993. Flora Neotropica 58: Calymperaceae.