Flora of North America species comparison

leaves long triangular-ovate, 1–2 mm; usually appressed;

apex acute to apiculate, hyaline cells only rarely septate or aporose but often fibrillose in apical region.

leaves to 1.1 × 0.7 mm, commonly hemiisophyllous;

hyaline cells non-ornamented, mostly 1–2-septate.

unranked, straight to slightly curved, leaves somewhat elongated at distal end.

short and blunt at distal end, leaves loosely spreading.

1.5–2.7 mm, ovate-lanceolate to lanceolate; straight to falcate toward branch tips; when dry often undulate and lightly recurved, margins entire to rarely weakly toothed along the margins in flaccid aquatic forms, hyaline cells on convex surface with 0–1 small round pores at apex, on 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 to broadly on the concave surface.

ovate, to 2.2 × 1.1 mm; ovate, hyaline cells non-ornamented, on proximal half of convex surface with small ringed pores or pseudopores in groups of three where the corners join and pseudopores along the commissures; chlorophyllous cells narrowly rectangular, lenticular to narrowly trapezoidal in transverse section; exposed equally on both surfaces or more broadly on concave surface;

end walls not thickened.

dioicous.

dioicous.

with numerous pseudostomata.

30–43 µm; the superficial surface coarsely papillose to papillose reticulate.

25–39 µm;

surface smooth to irregularly and finely papillose;

indistinct Y-mark on distal surface;

proximal laesura more than 0.6 spore radius.

fascicles with 2 spreading and 2–3 pendent branches.;

branch stems green, cortex enlarged with conspicuous retort cells.

fascicles with 2 spreading and 1–2 pendent branches.;

branch stems with hyaline cells non-ornamented, no or weak funnel-like projection of end walls of cortical cells, cortical cells with one large pore per cell on superficial wall.