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 triangular, large, less than 1.7 mm, mostly appressed to stem, apex weakly apiculate to narrowly obtuse;

hyaline cells efibrillose and seldom to often septate at base and sides.

weakly to strongly 5-ranked.

unranked, long and tapering, leaves greatly elongate 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.

ovate-lanceolate to lanceolate in aquatic forms, ovate to ovate-lanceolate in emergent forms, greater than 2.5 mm, often falcate-secund, especially in submerged forms, weakly undulate and recurved when dry;

margin entire, hyaline cells on convex surface with 0–1 pores per cell, concave surface with round wall thinnings in the cell apices and angles; chlorophyllous cells narrowly triangular in transverse section and well-enclosed on the concave surface.

dioicous.

dioicous.

18–33 µm, coarsely papillose on both surfaces;

proximal laesura less than 0.4 spore radius.

fascicles with 2 spreading and 1–2 pendent branches.

fascicles with 2 spreading and 2 pendent branches.;

branch stem green, cortex enlarged with conspicuous retort cells.

not seen.