Tortella (Lindb.) Limpr., Laubm Deutschl. 1: 599. 1888, nom. cons.
Mollia subg. Tortella Lindb., Musci. Scand. 21. 1879.
Plants small to medium-sized, yellow-green to green or dark-green above, brown, in loose tufts or cushions. Stems erect, sparsely and irregularly branched; hyalodermis present, central strand present or absent, rhizoids reddish brown, radiculose. Leaves ligulate to long-lanceolate, erect at base, appressed, erect or incurved, often twisted and contorted when dry, erect-spreading to spreading when wet; apices subulate, narrowly or broadly acute, at times rounded or cucullate; laminae unistratose, occasionally bistratose, at times fragile and broken above; margins entire, weakly crenulate by projecting papillae, at times dentate above, plane, erect, or incurved above; costa subpercurrent, percurrent or weakly excurrent as a short mucro, guide cells and two stereid bands present, ventral surface layer of enlarged cells; upper cells quadrate to hexagonal, firm-walled, pluripapillose, basal cells differentiated, enlarged, rectangular, walls thin or firm, at times porose, bulging, or long-rectangular to linear, hyaline, usually smooth, outer cells running up the margins farther than the interior cells forming a v-shaped pattern, alar cells not differentiated. Asexual reproduction by fragile leaf apices or lamina. Dioicous or autoicous; perichaetia terminal. Setae elongate, smooth. Capsules cylindrical or elliptical; stomata in neck; opercula long-conic to rostrate; annuli well-developed or rudimentary and non-functional; peristome of 32, linear, spiculose, counter-clockwise twisted teeth, rarely absent, basal membrane low or absent, or capsules cleistocarpous. Calyptrae cucullate.