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 appressed to stem or somewhat spreading; lingulate, ovate, to triangular; equal to or less than 0.9 mm;

apex obtuse and often erose to lacerate.

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

with leaves unranked to 5-ranked, leaves not much elongated at distal branch tip.

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, 1.1–1.3 mm long, stiff, weakly undulate and slightly recurved when dry;

hyaline cells in mid region quite short and broad, 3.3–2.5:1, in basal 1/2 of leaf on convex surface often with 1 large pore apically and/or up to 6 free pores, in apical region often with pseudopores along the cell margins;

on concave surface with large round wall-thinnings in the cell ends and angles (these sometimes faint or absent);

chlorophyllose cells triangular in transverse section and typically well-enclosed on concave surface.

dioicous.

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 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 2–3 pendent branches.

unknown.