Monographs Details: Tortula
Authority: Sharp, Aaron J., et al. 1994. The Moss Flora of Mexico. Part One: Sphagnales to Bryales. Mem. New York Bot. Gard. 69 (1)
Description:Genus Description - Plants small to large, in green, yellow- or red-brown tufts. Stems simple or forked; epidermal cells differentiated in 1-layers; central strand usually present. Brood bodies (if present) borne on the lamina or costa, in leaf axils, or on rhizoids, leaflike, spherical, or cylindric. Leaves appressed and variously twisted when dry, erect-spreading to squarrose when moist, obovate, spatulate, or lingulate (or rarely broadly oblong-lanceolate), acute to truncate or emarginate, and often apiculate to hair-pointed; margins plane or revolute, usually entire, not at all or variously bordered; costa generally strong, usually rounded at back, percurrent to long-excurrent as a hyaline or colored hair point, in section showing 1 median layer of large guide cells, 1-3 layers of smaller ventral cells, a weak or strong dorsal stereid band, and sometimes a group of hydroids and/or a dorsal epidermis of larger cells; upper cells quadrate to rounded-hexagonal, sometimes slightly longer than wide, small and obscure to large, lax, and pellucid, smooth or pluripapillose (or rarely unipapillose) on both surfaces, with branched, hollow papillae; marginal cells sometimes differentiated and short or elongate, thick-walled and colored or pale; basal cells gradually or abruptly differentiated, usually large and rectangular, smooth, hyaline, thin-walled, often lax. Perigonial bracts often short, ovate or oblong-lingulate, blunt, with costa often ending below the apex. Perichaetia terminal, the bracts not differentiated. Setae long, red or brown, smooth; capsules erect, straight or slightly curved, cylindric, sometimes with a distinct neck, red or brown, usually striolate when dry; operculum conic, straight or slightly oblique, shorter than the urn; peristome usually present, inserted below the mouth, and consisting of 32 filiform, reddish, papillose divisions slightly to strongly twisted together above a pale, tessellated basal membrane 1/10-2/3 the total length of the peristome. Spores finely to strongly papillose. Calyptrae long-cucullate, acute, yellow or brown.
The genus is generally characterized by a long, twisted peristome consisting of fihform divisions spirally wound together and joined at base as a tubelike membrane. The leaves, most often lingulate, are often awned or apiculate at the tip and revolute at the margins. The costa has a single stereid band. The green upper cells of the leaf are isodiametric and usually pluripapillose (usually with branched papillae that appear C-shaped in surface view), whereas the basal cells are laxly rectangular, pale, smooth, and often abruptly differentiated.
Zander (1989) segregated six genera from the inclusive concept of Tortula as it is presented here. Mexican representatives of his segregates are Chenia (rhizophylla), Dolotortula (mniifolia), Sagenotortula (quitoensis), and Syntrichia (ssp. 14-25).