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.

submersed, phyllodial, lenticular, to nearly terete, 12–53 × 0.3–0.7 cm;

rare stranded plants without expanded leaf blades.

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 2–7 whorls, floating or emersed, to 16 × 4 cm;

peduncles 13.5–28 cm;

bracts connate more than ¼ total length, ovate to lanceolate, 1.5–2 mm, delicate, not papillose; fruiting pedicels spreading to reflexed in flower and fruit, cylindric, 1.5–6.5 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.

1.5–5 cm diam.;

sepals spreading in staminate, appressed to spreading in flower and fruit in pistillate, often enclosing flower or fruiting head;

filaments dilated, longer than anthers, glabrous;

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 0.4–0.6 cm diam;

achenes oblanceoloid to obovoid, not abaxially keeled, 1.5 × 1 mm, beaked;

faces not tuberculate, wings absent, glands absent;

beak lateral, erect, 1.1 mm.

= 22.