Flora of North America species comparison

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

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

leaves to 1.7 × 1.2 mm; rarely hemiisophyllous;

hyaline cells nonseptate to occasionally septate, comb-lamellae absent.

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

long and tapering.

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.

broadly ovate, to 3 × 2.3 mm;

hyaline cells on proximal half of convex surface with elliptical pores along the commissures, often with ridges running parallel to long leaf axis on hyaline cell surface overlying chlorophyllous cells; chlorophyllous cells elliptical and just enclosed on both surfaces in transverse section;

end walls not thickened.

dioicous.

dioicous.

not seen.

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

proximal laesura less than 0.5 spore radius.

unknown.

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.

fascicles with 2 spreading and 2 pendent branches.;

branch stems with hyaline cells non-ornamented, no or weak funnel-like projections on the interior end walls, often with large round pores on the superficial wall.