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 usually smaller than branch leaves, triangular to lingulate, apex apiculate, acute, broad, or erose and split, border narrow or broad at base;

hyaline cells non-ornamented, usually efibrillose (in proximal portion) to often fibrillose in distal portion of leaf, aporose or with few pores and septate to nonseptate.

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

dimorphic, pendent branches more slender and delicate than spreading branches.

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.

usually longer than stem leaves, ovate to lanceolate;

margins entire or in a few cases serrulate;

apex involute and smooth;

hyaline cells non-ornamented, fibrillose (in one case efibrillose), convex surface porose or with a few to numerous pores or pseudopores, concave surface aporose or with pores or pore-like wall thinnings; chlorophyllous cells triangular to trapezoidal in transverse section, more broadly exposed on convex surface, end walls not thickened.

dioicous.

mostly dioicous or occasionally monoicous.

less than 2 mm, with few pseudostomata.

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

proximal laesura less than 0.5 spore radius.

usually more than 30 µm, rarely with raised surface sculpture on distal surface;

proximal laesura typically less than or equal to 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 2–3 spreading to 1–3 pendent branches.;

branch stems green to pinkish, surrounded by 1 layer of efibrillose, non-ornamented, enlarged, thin-walled cells, with solitary uniporose retort cells (or in groups) with short necks, other aporose cells rectangular.