Flora of North America species comparison

leaves to 2 × 0.7 mm; rarely hemiisophyllous;

hyaline cells non-ornamented, mostly nonseptate.

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.

long and tapering to short and pointed, leaves loosely imbricate.

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

broadly ovate, to 2 × 1 mm or more wide, broadly ovate, hyaline cells non-ornamented, convex surface with round to elliptic pores along the commissures; chlorophyllous cells short-elliptic in transverse section and well-enclosed on both surfaces.

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.

with numerous pseudostomata.

22–30 µm; roughly papillose to nearly smooth, with distinct Y-mark sculpture on distal surface;

proximal laesura 0.5–0.8 spore radius.

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

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

branch stems with hyaline cells non-ornamented;

no or weak funnel-like projections on the interior end walls, large round pores on superficial cell walls.

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

branch stems green, cortex enlarged with conspicuous retort cells.