Flora of North America species comparison

leaves quite variable in shape, elongate-lingulate to ovate, broadest above the middle, 1.9–2.5 mm, slightly concave, straight;

apex broad and toothed;

hyaline cells narrowly rhomboid, 0–1-septate, distal portion fibrillose, convex surface with membrane pleats, concave surface with 1(2–3) oblong membrane gaps.

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.

rarely 5-ranked.

unranked, long and tapering, leaves greatly elongate at distal end.

ovate, 1.6–2.2 mm, concave, straight;

apex stiffly involute and broadly truncate with up to 8 teeth, border denticulate due to cell wall resorption and projecting cell walls;

hyaline cells strongly bulging on convex surface and nearly plane on the concave surface, convex surface with narrowly elliptic pores along commissures grading from smaller pores near the apex to large rounded pores at base, concave surface with large round pores in proximal regions 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.

monoicous.

dioicous.

27–33 µm, finely papillose on both surfaces with distinct bifurcated Y-mark sculpture on distal surface;

proximal laesura less than 0.5 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.