Calyptothecium Mitt., J. Linn. Soc., Bot. 10: 190. 1868.
Plants somewhat small to rather large, forming loose tufts, glossy green. Primary stems creeping, wiry, leaves scale-like, usually eroded. Secondary stems erect, simple and unbranched, or frondose and several branched. Leaves rather complanate, somewhat differentiated between median mostly symmetric leaves and lateral asymmetric leaves, concave, strongly so with lateral leaves, broadly ovate-short lanceolate, apex acute or broadly short acuminate, base auriculate; margins plane or incurved distally, entire to weakly serrulate distally; costae single, ca. 2/3 lamina length, usually forked below; median cells linear, somewhat vermicular, smooth, weakly porose; insertion cells strongly porose, golden-brown; alar cells differentiated, subquadrate, porose. Propagula present in leaf axial on distal stem and branches, cylindrical, smooth. Dioicous. Perichaetia lateral, leaves oblong-lanceolate, convolute. Setae short to somewhat elongate. Capsules immersed to shortly exserted, urn ovoid-cylindrical; opercula conic-rostrate; peristome double although often rudimentary or absent. Calyptrae mitrate. Spores not observed.