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).

to 2.5 cm (sometimes not developed), tip pointed;

sheath not winged.

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

ovaries 1-ovulate, utricular scale with narrow opening at apex.

0.5–0.8 mm, not winged.

0.6–0.9 mm, laterally winged toward apex.

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

with 12–18 distinct ribs, staying within fruit wall after ripening.

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.

submersed (except when flowering or fruiting), 3–50, coherent and very often forming branched chains, narrowly ovate, flat, thin, 3–15 mm (excluding stalk), 2–3.5 times as long as wide, base suddenly narrowed into green stalk, margins denticulate distally;

veins (1 or) 3, lateral veins only in proximal part of frond;

papillae absent;

anthocyanin often present;

air spaces shorter than 0.3 mm;

turions absent.

stalks 2–20 mm.

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

= 40, 42, 44, 60, 63, 80.