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, 1.3–1.6 mm, apex broadly rounded or pointed and notched (sometimes denticulate), border strong and broadened at base (more than 0.25 width);

hyaline cells short sinuoid-rhombic, mostly efibrillose, 0–1(–2)-septate.

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

long and slender, never 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, 1.3–1.6 mm, concave, straight, apex strongly involute;

hyaline cells on convex surface with numerous round to elliptic pores along the commissures, grading from small round pores near the apex to large elliptic pores at the base, concave surface usually with large round pores throughout, but sometimes restricted to proximal portions of leaf.

dioicous.

dioicous, but some specimens apparently monoicous.

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

proximal laesura less than 0.5 spore radius.

18–33 µm, coarsely papillose on both surfaces;

proximal laesura more 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.