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 equilateral triangular, 0.8–1.1 mm; often spreading;

apex more or less obtuse;

leaves often spreading;

hyaline cells usually septate and often fibrillose in proximal half of leaf.

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

unranked, ± straight, leaves moderately elongated at distal end.

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.

ovate-lanceolate, less than 2.2 mm, straight; undulate and sharply recurved when dry;

margins entire;

hyaline cells on convex surface with 0–1 apical pores and often with pseudopores, concave surface with to 12 round wall thinnings in cell angles and sometimes along commissures; chlorophyllous cells triangular in transverse section, just enclosed on the concave surface and broadly exposed on the convex surface.

dioicous.

unknown.

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

proximal laesura less than 0.5 spore radius.

not seen.

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 1–2 pendent branches.;

branch stems green, with cortex enlarged with conspicuous retort cells.