Flora of North America species comparison

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

sheath not winged.

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

0.6–0.9 mm, laterally winged toward apex.

with 12–18 distinct 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.

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