Flora of North America species comparison

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

sheath not winged.

to 3.5 cm, tip usually sharp pointed;

sheath narrowly winged at base (wing 2–3 times as long as wide).

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

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

0.6–0.9 mm, laterally winged toward apex.

0.7–1 mm, not winged.

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

with 35–70 indistinct ribs, staying within fruit wall after ripening.

stalks 2–20 mm.

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.

floating, 1 or 2–few, coherent in groups, ovate-obovate, flat, 1–4 mm, 1–1.7 times as long as wide, margins entire;

veins 3, greatest distance between lateral veins near or distal to middle; 1 distinct papilla near apex on upper surface, 2–3 very distinct papillae above node;

anthocyanin absent, no reddish color;

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

white, small, often decaying.

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

= 40 (U), 42 (G).