Isopterygiella Ignatov & Ignatova

Ignatova, E. A., Fedorova, A. V. & Ignatov, M. S., 2020, On the genera Isopterygiopsis and Isopterygiella, gen. nov. (Plagiotheciaceae) in Russia, Arctoa 29 (1), pp. 49-62 : 57-59

Isopterygiella Ignatov & Ignatova , gen nov.

Diagnosis. The new genus differs from Isopterygiopsis in having terete or indistinctly complanate vs. strongly complanate foliage; leaves often homomallous to falcate-secund vs. straight to slightly homomallous; plants autoicous or apparently dioicous (only one sex is known) vs. dioicous; operculum high conic vs. rostrate.

Type species: Isopterygiella pulchella (Hedw.) Ignatov & Ignatova (= Leskea pulchella Hedw. ).

Description. Plants small or minute, green or yellowish-green, silky glossy, in small soft patches. Stems terete-foliate or indistinctly complanate, sparsely and irregularly branched; central strand present; hyalodermis well-developed or absent, in the latter case epidermal cells with thinner outer walls; rhizoids axillary, purple, coarsely papillose. Leaves straight or slightly falcate-secund, ovate-lanceolate to lanceolate, narrowly acute or acuminate; margins entire or serrulate near apex or throughout; costa short, double; laminal cells linear, basalmost cells shorter and wider, alar cells not differentiated or few alar cells quadrate to short rectangular. Specialized asexual reproduction by axillary propagulae of 3–4 cells in one row. Autoicous or apparently dioicous (male plants unknown). Inner perichaetial leaves short. Capsules erect to inclined, cylindric to slightly, rarely moderately curved. Operculum conic, sometimes with an apiculus. Annulus revoluble, of 2–3 rows of cells. Peristome slightly reduced; exostome teeth whitish, striolate below, papillose above; basal membrane of endostome ca. 40% of exostome teeth length, segments narrow, not perforated, cilia 1–2, short to about as long as exostome teeth, nodose. Spores 10–15 µm. Calyptra cucullate.

The genus inclides two species.