Robert R. Ireland
Sharpiella Z. Iwatsuki
Plants medium-sized, in thin to dense, light- to yellow-green or dark green glossy mats. Stems creeping to ascending, simple or sparingly and irregularly branched, epidermal cells large and thin-walled in section, surrounding a few rows of smaller thick-walled cortical cells and large thin-walled central cells, central strand usually absent; rhizoids sparse, papillose, in leaf axils or just below juncture of leaves, often restricted to base of stems; axillary hairs with two brownish short-rectangular basal cells and two hyaline elongate apical cells; pseudoparaphyllia lacking or foliose pseudoparaphyllia present (H. adscendens). Specialized asexual reproduction lacking. Stem and branch leaves similar, rigid, crowded and imbricate to somewhat remote, spreading to squarrose, sometimes tips secund at stem and branch apices, concave, smooth or weakly plicate, symmetric, nondecurrent or 1--3 cells decurrent, ovate or lanceolate, acuminate; margins plane, serrulate to strongly serrate beyond leaf middle, serrate to entire below; costa short and double, rarely lacking; cells thick-walled, linear-fusiform, smooth, cell walls at leaf base usually pitted; alar cells usually clearly differentiated, a few quadrate, rectangular, or abruptly inflated and rounded cells present, 1--4 on margins. Sexual condition autoicous or dioicous. Perigonia and perichaetia near base of stems, perichaetial leaves ovate-lanceolate, gradually acuminate occasionally to a filiform acumen, sometimes plicate, margins plane. Seta smooth, elongate, straight to curved, often twisted, yellow, brown or red. Capsule erect to cernuous, straight to arcuate, yellow, brown or reddish brown, oblong or cylindric, when dry usually striate, sometimes smooth, tapering to a wrinkled neck, often contracted below mouth; operculum conic to short-rostrate; annulus of 2--3 rows of large cells, deciduous; peristome cross-striolate proximally, papillose distally, bordered, interior trabeculate; endostome papillose, consisting of narrow keeled segments from a high basal membrane, cilia 1--3, approximately the length of segments, sometimes lacking. Calyptra cucullate, smooth, naked. Spores spherical to ovoid, minutely papillose.
Species 7 (4 in the flora): terrestrial habitats at low to high elevations predominately in temperate and boreal regions; North, Central and South America, Europe, Asia, Africa.
Ireland, R. R. 1969. A taxonomic revision of the genus Plagiothecium for North America, north of Mexico. Natl. Mus. of Canada, Natl. Mus. Natural Sci., Publ. Bot. 1: 1--118. Ireland, R. R. 1990 (1992). Scanning electron microscopy of spores of Herzogiella. Lindbergia 16: 169--179. Ireland, R. R. 1991 (1993). Synopsis of the genus Herzogiella for North America. Lindbergia 17: 111--115. Iwatsuki, Z. 1965. Notes on the genus Dolichotheca, with special reference to the Japanese species. J. Hattori Bot. Lab. 28: 202--208. Iwatsuki, Z. 1970. A revision of Plagiothecium and its related genera from Japan and her adjacent areas, I. J. Hattori Bot. Lab. 33: 331--380.
Crum, H. A. and L. E. Anderson. 1981. Mosses of Eastern North America. Vol. 2. Columbia University Press, New York.
Iwatsuki, Z. and W. B. Schofield. 1973. The taxonomic position of Campylium adscendens (Lindb.) Mitt. J. Hattori Bot. Lab. 37: 609--615.