Flora of North America species comparison

leaves lingulate-triangular to lingulate, 1–1.4 mm, apex broadly rounded but becoming acute in hemiisophyllous forms, border strongly developed at base (more than 0.25 width);

hyaline cells rhombic and 0–3-septate with some cells in leaf midregion 2–septate.

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.

weakly to strongly 5-ranked.

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

ovate to ovate-lanceolate, 0.9–1.2 mm, concave, subsecund on some branches, apex involute;

hyaline cells on convex surface with numerous round to elliptic pores along the commissures, grading from small round pores near apex to round pores near base, on concave surface with large round pores in proximal portions of leaf.

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.

dioicous.

dioicous.

18–33 µm, coarsely papillose on both surfaces;

proximal laesura less than 0.4 spore radius.

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

fascicles with 2 spreading and 1–2 pendent branches.

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

branch stems green, cortex enlarged with conspicuous retort cells.