Sarmentypnum
Dioicous. In mineral rich fens. Stems sparsely to densely irregularly branched and radiating in all directions, with sparse rhizoids in rows or at scattered points along length; outer pseudoparaphyllia triangular to broader than long and irregular; central strand present. Stem and branch leaves similar, ovate to triangular or oblong (not in Victoria), falcate or straight when moist, scarcely altered when dry, not or distinctly (not in Victoria) decurrent; apex acuminate, obtuse (not in Victoria) or rounded (not in Victoria) and usually apiculate; costa single, extending 3/5 of leaf length to excurrent (not in Victoria); margin entire or denticulate, plane; laminal cells linear, smooth, unistratose; alar cells differentiated, quadrate to rectangular, inflated, hyaline, forming a distinctly defined transversely triangular region that extends from margin to or near costa. Capsule inclined to horizontal, curved, cylindric, with an annulus. Calyptra cucullate, smooth, glabrous. Operculum conic. Peristome double; endostome segments same height as exostome, with a high basal membrane; cilia present.
Seven species throughout northern temperate and boreal regions, temperate Australia, New Zealand and South America, subantarctic islands south of South America, Antarctica and at high altitude throughout the tropics; one species in Victoria.
The dioicous species formerly included in Warnstorfia formed a group more closely related to other genera of the Calliergonaceae than to the autoicous species of Warnstorfia in a phylogeny of chloroplast and nuclear DNA and morphological characters, providing a primary basis for recognising these two groups as separate genera (Hedenäs 2006). The type of Warnstorfia is the autoicous, W. fluitans (Hedw.) Loeske, and the genus Sarmentypnum was previously erected for the dioicous W. sarmentosa (Wahlenb.) Hedenäs, so all remaining dioicous Warnstorfia species were transferred to Sarmentypnum by Hedenäs (2006).
SpinningHedenäs, L. (2006). Additional insights into the phylogeny of Calliergon, Loeskypnum, Straminergon, and Warnstorfia (Bryophyta: Calliergonaceae). Journal of the Hattori Botanical Laboratory 100: 125–134.