Flora of North America species comparison

leaves triangular-lingulate, 1.2–1.4 mm;

apex with a deep lacerate split;

hyaline cells aporose, efibrillose and often septate.

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

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

unranked to rarely 5-ranked, branch leaves only weakly undulate, but sharply recurved at the apex, leaves not much elongated at distal end.

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

ovate-lanceolate; 2–2.6 mm; straight; weakly undulate but strongly recurved, hyaline cells on convex surface with very large irregular pores (formed from the confluence of several smaller pores) at the cell apex, concave surface with large round wall thinnings in the cell angles; chlorophyllous cells triangular to trapezoidal in transverse section, apex normally slightly exposed on concave surface.

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.

dioicous.

dioicous.

22–28 µm;

proximal surface noticeably papillose, distal surface smooth or with fewer papillae;

proximal laesura more than 0.5 the length of the radius.

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 pendent branches.;

branch stem green, cortex enlarged with retort cells.

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.