Flora of North America species comparison

leaves triangular, ovate-triangular to triangular-lingulate, 1–1.3 mm; appressed to spreading;

apex obtuse, hyaline cells usually fibrillose near apex.

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.

straight to somewhat curved, leaves moderately elongate at distal end.

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

ovate-lanceolate; usually more than 2 mm; straight; weakly undulate and slightly recurved when dry, margins entire;

hyaline cells on convex surface with numerous small free pores in proximal 2/3 of leaf and in apical region with numerous pseudopores along commissures, on concave surface with numerous round free pores;

cells relatively long and narrow in basal region, much longer than in mid region; chlorophyllous cells triangular in transverse section and well-enclosed on concave surface.

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.

29–33 µm;

both surfaces very smooth;

proximal laesura long, more than 0.6 spore radius.

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

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

branch stems green, cortex enlarged with conspicuous retort cells.

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

branch stems green, cortex enlarged with conspicuous retort cells.