Flora of North America species comparison

leaves equilateral to isosceles-triangular, small, less than 0.8 mm, mostly appressed to stem, apex acute to obtuse, hyaline cells efibrillose and nonseptate.

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

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

straight to slightly curved, usually 5-ranked;

leaves not much longer at distal end than proximal end.

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

narrowly ovate-lanceolate, 0.8–1 mm, straight, moderately undulate and recurved in larger and/or wetter grown forms, not undulate and slightly recurved in compact forms from drier sites;

margins entire;

hyaline cells on convex surface with 1(2–3) pore per cell at apical end of cell, on concave surface with round wall thinnings in cell ends and angles; chlorophyllous cells triangular in transverse section and just enclosed 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.

21–25 µm; coarsely papillose on proximal and distal surfaces;

proximal laesura more than 0.5 spore 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 2–3 pendent branches.;

branch stems with cortex enlarged with conspicuous retort cells, often pinkish red at proximal end.

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.