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 to 1.2–2.2 × 0.8–1 mm; rarely hemiisophyllous;

hyaline cells non-ornamented, rarely septate, comb-lamellae absent.

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

tapering, leaves spreading to somewhat imbricate.

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.

broadly ovate, to 1.7 × 1.5 mm;

hyaline cells non-ornamented, convex surface with elliptic to rarely round pores along the commissures; chlorophyllous cells lenticular to narrowly elliptical in transverse section, narrowly exposed on both ends, but more so on concave surface, end walls thickened at both ends.

dioicous.

dioicous.

with inconspicuous pseudostomata.

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

proximal laesura less than 0.5 spore radius.

23–30 µm;

surface finely roughened to smooth;

laesura on proximal surface more 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 1–2 pendent branches.;

branch stems with cortical cells non-ornamented, no or weak funnel-like projections on the interior end walls, often with large round pores on the superficial walls.