Tortula

Description

Plants small size, growing in loose, dense turfs or gregarious, yellowish green to brown. Stems usually branched; in cross-section circular, hyalodermis undifferentiated, sclerodermis absent or with the outer cells smaller and with thicker-walled, central strand differentiated, sometimes weakly; axillary hairs of hyaline cells. Rhizoids, brownish, smooth; rhizoidal and protonematic gemmae sometimes developed. Leaves incurved to spirally twisted when dry, erect-patent to spreading when moist, usually ovate to lingulate or spathulate, occasionally orbicular, obovate, linear, oblong or elliptical, flat to concave; base usually not differentiated; lamina unistratose, yellow, rarely orange or with spots with KOH;; apex rounded to acute, sometimes tapering to the apex, apiculate or not, occasionally cucullate; margins papillose-crenulate or entire, rarely denticulate near apex, revolute to recurved, occasionally plane, uni to bistratose, bordered or not, sometimes intramarginally, by short-rectangular to linear or oblate cells, usually less papillose or smooth and thicker walls than the rest of the laminal cells; costa usually excurrent in a mucro, apiculus or hair-point hyaline, yellowish or brownish, smooth, rarely percurrent or ending below the apex; ventral surface cells of the costa mostly rectangular to quadrate or rounded, papillose or smooth, bulging or not; dorsal surface cells of the costa rectangular to linear, smooth or papillose; in cross-section semicircular, circular or elliptical with guide cells in one or two layers, band of ventral stereids usually undifferentiated, band of dorsal stereids differentiated, semicircular or circular, more rarely oval in shape, sometimes with substereids, hydroids scarcely or well-developed, ventral surface cells differentiated, usually quadrate to rectangular, rounded, disposed in one or two layers; dorsal surface cells differentiated; upper and middle laminal cells usually quadrate, short-rectangular or hexagonal, sometimes romboidal, rounded or oblate, usually thin-walled, not or slightly collenchymatous, smooth or more commonly papillose, with simple or bifurcate papillae; upper and middle marginal cells oblate, quadrate to rectangular or linear, rarely rounded or rhomboidal, usually thick-walled, smooth or papillose; basal laminal cells rectangular, sometimes oblate, usually inflate, hyaline, thin-walled, not or slightly collenchymatous, usually smooth; basal marginal cells quadrate to long-rectangular, thin to slight thick-walled, smooth. Dioicous or monoicous. Perichaetia terminal; leaves usually undifferentiated, rarely sheathing at base. Seta erect or curved, rarely slightly flexuose, usually spirally twisted to right above and to left below, sometimes straight or spirally twisted to the left throughout, smooth, yellowish to reddish brown. Capsule erect, rarely horizontal to cernuos, cleistocarpous or stegocarpous, immersed or exserted; theca ovoid to cylindrical, more rarely globose, elliptical or turbinate, orange to reddish brown; exothecial cells quadrate to rectangular, thin to thick-walled; stomata at theca base, superficial; annulus of 1-3 vesiculose or rounded, sometimes quadrate rows of cells, usually persistent, sometimes undifferentiated; peristome undifferentiated or of 16 or 32 filamentous or plane, sometimes anastomosed, papillose, spirally twisted or straight teeth, yellowish to orange or brownish, basal membrane usually differentiated, papillose, yellowish to orange or brown. Operculum long conical to rostrate, sometimes undifferentiated, occasionally systylious, with spirally twisted cells or in straight rows, orange to reddish brown. Calyptra cucullate, sometimes slightly mitrate, smooth, naked, yellow to brownish. Spores spherical to elliptical, granulate, sometimes clavate, baculate, verrucose or vermiculate, yellowish to brown.