Flora of North America species comparison

to 3 cm;

tip usually sharp pointed;

sheath winged at base (wing 1–2.5 times as long as wide).

1 per frond.

ovaries 1-ovulate, utricular scale open on 1 side.

1(–2) per frond, surrounded by small utricular, membranous scale;

stamens 2, 4-locular.

0.5–0.8 mm, not winged.

with 8–26 distinct ribs, falling out of fruit wall after ripening.

1–5, longitudinally ribbed.

small, white, often decaying.

floating, 1 or 2–few, coherent in groups, ovate-lanceolate, flat, 1–6 mm, 1–3 times as long as wide, margins entire;

veins 3, greatest distance between lateral veins near or proximal to middle; 1 often very distinct papilla near apex on upper surface and 1 above node;

anthocyanin absent, no reddish color;

largest air spaces much shorter than 0.3 mm; distinct turions absent.

floating or submersed, 1 or 2–20 or more, coherent in groups or forming chains, lanceolate-ovate, flat or gibbous, 1–15 mm, margins entire or denticulate, upper surfaces sometimes with small conic papillae along veins (especially at node and near apex);

air spaces in tissue;

reproductive pouches 2, lateral, at base from which daughter fronds and flowers originate, triangular;

veins 1–5(–7), originating from point in proximal part of frond (node) or if more than 3 veins present, outer ones sometimes branching distally from inner ones;

scale at base of frond absent;

anthocyanins sometimes present;

pigment cells absent (red pigmentation present in some species);

turions absent (sometimes present in L. turionifera).

= 10, 21, 22

= 40, 42, 50, 60, 80, 84.