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 broadly ovate, 3.5–4 mm, apex rounded and indistinctly toothed;

hyaline cells on convex surface with 10–20 small (2.5–7.5 µm) round pores approximately 1/6 the diameter of the hyaline cells along the commissures, cells on concave surface uniporose in distal end or aporose, sometimes one or a few pores are scattered over the surface of the cells.

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

few, single and short or more commonly none.

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.

if any, are usually slightly smaller, 2–3 mm, but otherwise identical to the stem leaves.

dioicous.

dioicous.

immersed in perichaetial leaves, pseudopodium extremely short, without pseudostomata.

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

25–40 µm; coarsely papillose on both surfaces;

proximal laesura more than 0.5 the length of the spore

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

branch stems green, cortex enlarged with conspicuous retort cells.

fascicles, if any, usually only 1 single branch.