Flora of North America species comparison

green to dark brown, superficial cortex of 0–3 layers of efibrillose, non-ornamented, enlarged, thin-walled cells;

cells in outer layer aporose or with single round to elliptical wall thinning adjacent to the distal cell wall, visible only with heavy staining.;

stem leaves varying from smaller than to larger than branch leaves;

triangular, ovate to lingulate;

with rounded and sometimes erose apex;

border entire;

hyaline cells rhomboid to S-shaped, non-ornamented, efibrillose to fibrillose, aporose to sometimes porose, non- to multiply septate;

neither surface resorbed.

leaves lingulate to ovate-lingulate, 1.3–2 mm;

apex truncate to rounded, usually denticulate;

hyaline cells typically fibrillose for 1/2 of leaf or more, often 1–2-septate, convex surface with 4–12 or more pores per cell along the commissures, concave surface with fewer pores.

not always clearly dimorphic, spreading and pendent branches very similar.

usually curving, often large and tumid.

oval, ovate or ovate-lanceolate;

hyaline cells fibrillose, non-ornamented;

convex surface mostly with numerous elliptical to round pores (8–24 per cell) in rows along commissures on convex surface, concave surface with fewer or no pores; chlorophyllous cells elliptical in transverse section, ± equally exposed on both surfaces or slightly more on convex surface, end walls not thickened.

broadly ovate to ovate-lanceolate, 1.3–2.5 mm, greatly elongated in aquatic forms, straight or infrequently subsecund or subsquarrose;

hyaline cells with 10–22 pores along the commissures on the convex surface, no or fewer pores per cell (1–8) on the concave surface.

dioicous.

dioicous.

with few pseudostomata.

exserted, with few pseudostomata.

22–41 µm, with or without raised surface sculpture on distal surface;

proximal laesura more than 0.5 spore radius.

27–34 µm; finely papillose on both surfaces, with distinct raised Y-mark sculpture (indistinctly bifurcated Y-mark) on the distal surface;

proximal laesura less than 0.5 spore radius.

fascicles 1–3 spreading and 0–2(–4) pendent.;

branch stems green, surrounded by 1 layer of efibrillose, non-ornamented, thin-walled, inflated cells, with solitary short-necked retort cells or with conspicuously necked retort cells, interspersed with primarily aporose rectangular-shaped cells.

fascicles with 2(rarely 3) spreading and 1–2(–3) pendent branches.