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 very small, less than 0.8 mm, triangular with blunt rounded apex.

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

erect in distal portion of plants.

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.

large, 2.8 mm or longer, sub-squarrose, ovate, involute to broad, truncate apex with more than 6 teeth;

hyaline cells with up to 6 non-ringed pores on convex surface with few or no pseudopores, 2–4 elliptic ringed pores on concave surface in corners or along commissures, internal commissural walls minutely papillose (best viewed in oblique sections), rarely smooth; chlorophyllous cells narrowly triangular in transverse section, more broadly exposed on convex surface, enclosed on concave surface.

dioicous.

monoicous.

with abundant pseudostomata on surface of capsule.

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

proximal laesura less than 0.5 spore radius.

31–43 µm; coarsely papillose on both proximal and distal surfaces, raised Y-mark sculpture on distal surface;

proximal laesura moderately long, 0.4–0.7 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 short-spreading and 3 long-tapering pendent branches.