Flora of North America species comparison

leaves quite variable in shape, elongate-lingulate to ovate, broadest above the middle, 1.9–2.5 mm, slightly concave, straight;

apex broad and toothed;

hyaline cells narrowly rhomboid, 0–1-septate, distal portion fibrillose, convex surface with membrane pleats, concave surface with 1(2–3) oblong membrane gaps.

leaves triangular-ovate, more than 1.2 mm, usually appressed;

apex acute to apiculate, hyaline cells rarely septate or porose, apical region often fibrillose.

rarely 5-ranked.

mostly unranked to weakly 5-ranked, often conspicuously falcate, leaves greatly elongated at distal end.

ovate, 1.6–2.2 mm, concave, straight;

apex stiffly involute and broadly truncate with up to 8 teeth, border denticulate due to cell wall resorption and projecting cell walls;

hyaline cells strongly bulging on convex surface and nearly plane on the concave surface, convex surface with narrowly elliptic pores along commissures grading from smaller pores near the apex to large rounded pores at base, concave surface with large round pores in proximal regions of leaf.

ovate-lanceolate to lanceolate, 1.6–5 mm, falcate toward branch tips, when dry often undulate and recurved, rarely weakly serrulate along the margins in submerged forms, leaves from middle of spreading branches with length to width ratio less than or equal to 1:0.28;

hyaline cells length to width ratio in apical convex surface region 8:1 or more, convex surface with 0–1 small round pores at apex, concave surface with faint round wall thinnings in cell apices and angles; chlorophyllous cells triangular to trapezoidal in transverse section, broadly exposed on the convex surface and exposed slightly on the concave surface.

monoicous.

dioicous.

27–33 µm, finely papillose on both surfaces with distinct bifurcated Y-mark sculpture on distal surface;

proximal laesura less than 0.5 spore radius.

29–38 µm; covered with large papillae on both surfaces, appearing pusticulate;

proximal laesura less than 0.5 spore radius.

fascicles with 2 spreading and 1–2 pendent branches.

fascicles with 2 spreading and 2–3 pendent branches.;

branch stems green, but often pinkish at the proximal ends, with cortex enlarged with conspicuous retort cells.