Flora of North America species comparison

emersed, floating, and submersed; submersed phyllodial, flattened, to 45 cm; floating with petiole triangular, to 100 cm, blade cordate or sagittate, rarely linear or ovate, 7.5–9 × 3.5–4 cm; emersed with petiole recurved, 3.5–51 cm, blade linear to sagittate, 2.5–17 × 1.5–11 cm, basal lobes when present shorter than remainder of blade.

mostly submersed, rarely emersed, sessile, phyllodial, flattened to lenticular, 5–30 × 0.2–0.5 cm.

racemes, rarely panicles, of 2–10 whorls, emersed, 14–21 × 2–10 cm, peduncle triangular, 10–50 cm;

bracts connate more than or equal to ¼ total length, lance-attenuate or acute, mostly (4–)7–40 mm, membranous, not papillose; fruiting pedicels ascending, cylindric, 0.5–2 cm.

racemes, of 2–5 whorls, emersed, 1.5–8 × 1–7 cm;

peduncles 1–2.5 cm;

bracts connate more than or equal to ¼ total length, lanceolate, 0.5–1.5 mm, delicate, not papillose; fruiting pedicels spreading, cylindric, 0.6–2.5 cm.

to 25 mm diam.;

sepals recurved, not enclosing flower or fruiting head;

filaments not dilated, equal to or longer than anthers, glabrous;

pistillate pedicellate, without ring of sterile stamens.

to 2.5 cm diam.;

sepals recurved to spreading, not enclosing flower or fruiting head;

filaments dilated, shorter than anthers, minutely tomentose;

pistillate pedicellate, without ring of sterile stamens.

heads 0.8–1.5 cm diam.;

achenes obovoid, abaxially keeled, 1.8–2.6 × 1.3–2.5 mm, beaked;

face not tuberculate, wings 0–1, ± entire, glands 0–1;

beak apical, erect, 0.1–0.4 mm.

heads 0.5 cm diam;

achenes obovoid-triangular, abaxially keeled, 2 × 1 mm, beaked;

faces tuberculate, wings 1, scalloped or toothed, glands 0–1;

beak lateral, incurved-erect, 0.3 mm.

= 22.