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 lingulate, 0.8–1.3 mm;

apex broadly rounded and entire to lacerate, sometimes slightly mucronate or slightly denticulate;

hyaline cells rhombic, 0–1(–2)-septate, usually efibrillose.

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

long and slender to short and compact, unranked to 5-ranked.

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, 1.1–1.3 mm, straight, concave, apex strongly involute;

margins entire, hyaline cells on convex surface with round to elliptic pores along the commissures, grading from small pores near the leaf apex to large pores near the base, concave surface with large round pores in proximal marginal regions of leaf.

dioicous.

dioicous.

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

proximal laesura less than 0.5 spore radius.

17–30 µm, finely papillose on proximal surface and pusticulate on distal surface;

proximal laesura less than 0.5 spore radius.

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.