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 1.3 × 0.7 mm; rarely hemiisophyllous;

hyaline cells non-ornamented, mostly septate.

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

generally short and blunt, leaves 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.

broadly ovate, 1.7 × 1 mm;

hyaline cells on convex surface with round to elliptic pores along the commissures, hyaline cell walls covered with papillae where overlying chlorophyllous cells; chlorophyllous cells trapezoidal to truncate-elliptic in transverse section, equally exposed on both surfaces or less exposed on convex surface, end walls thickened.

dioicous.

dioicous.

with numerous pseudostomata.

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

26–36 µm; more roughly papillose on distal surface than proximal surface, distinct raised, bifurcated-Y mark sculpture on distal surface;

proximal laesura 0.5 spore radius or more.

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

branch stems green, cortex enlarged with conspicuous retort cells.

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

branch stems with hyaline cells non-ornamented, no or weak funnel-like projections on the interior end walls, mostly with 1 pore per cell on superficial cell wall.