Isopterygiella
Autoicous or possibly dioicous (not in Victoria). Asexual reproduction by axillary gemmae. Mats on soil, rocks, logs or trees. Stems creeping, simple or sparsely and irregularly branched, with purplish rhizoids in leaf axils; central strand present. Leaves ovate-lanceolate to lanceolate, arranged around stem and facing all directions, monomorphic, erect-spreading when moist, scarcely altered when dry, straight to slightly falcate-secund, not decurrent; apex acuminate; costa short and double; margin entire or serrulate at apex, plane or erect; laminal cells linear, shortest near base, smooth; alar cells not or scarcely differentiated or a few quadrate to short-rectangular. Capsule erect to pendent, straight or slightly curved, ovoid to cylindric. Calyptra cucullate, smooth, glabrous. Operculum conic, sometimes apiculate. Endostome with a basal membrane c. 40% of exostome teeth height; cilia present.
Two species; one species throughout the northern temperate zone and a second also in the southern temperate zone.
Isopterygiella was recently segregated from Isopterygiopsis based on its two species not forming a group with Isopterygiopsis in phylogenies of all genomic compartments and the supporting morphological differences between the two genera, including a difference in leaf arrangement, with Isopterygiella having leaves arranged around the stem and facing all directions rather than complanate as in Isopterygiopsis (Ignatova et al. 2020). Both genera were previously placed in Isopterygium but were removed from that genus due to their lack of pseudoparaphyllia, axillary rhizoids, filamentous gemmae and a differentiated annulus (Iwatsuki 1970).
Ignatova, E.A.; Fedorova, A.V.; Ignatov, M.S. (2020). On the genera Isopterygiopsis and Isopterygiella, gen. nov. (Plagiotheciaceae) in Russia. Arctoa 29: 49–62.
Iwatsuki, Z. (1970). A revision of Plagiothecium and its related genera from Japan and her adjacent areas. I. Journal of the Hattori Botanical Laboratory 33: 331–380.