Flora of North America species comparison

submersed or emersed; submersed leaves phyllodial, angled abaxially, flattened adaxially, 6.4–35 × 0.5–4 cm; emersed with petiole triangular, 6.5–17 cm, blade linear to linear-oblanceolate, 2.5–17.4 × 0.2–4 cm.

emersed;

petiole 5-ridged, ascending to erect, 24.5–60 cm;

blade sagittate, 11.5–26.5 × 0.8–15 cm, basal lobes longer than remainder of blade.

racemes or panicles, of 1–12 whorls, emersed, 2.5–21 × 1–8 cm;

peduncles 6.5–29.7 cm;

bracts connate more than to equal to ¼ total length, broadly subulate to lanceolate, 20–50 mm, coarse, not papillose; fruiting pedicels spreading, cylindric, 0.5–5 cm.

racemes, rarely panicles, of 5–17 whorls, emersed, 20–37 × 5–27 cm;

peduncles 25–96 cm;

bracts connate more than or equal to ¼ total length, lanceolate, 6.5–15 mm, delicate, not papillose; fruiting pedicels spreading, cylindric, 1.5–4.4 cm.

to 2.3 cm diam.;

sepals recurved to spreading, not enclosing flower;

filaments dilated, shorter than anthers, pubescent;

pistillate flowers pedicellate, without ring of sterile stamens.

to 3 cm diam.;

sepals recurved to spreading, not enclosing flower;

filaments cylindric, shorter than anthers, glabrous;

pistillate flowers pedicellate, without ring of sterile stamens.

heads 0.6–1.5 cm diam.;

achenes oblanceoloid, without abaxial keel, 1.5–2.8 × 1.1–1.5 mm, beaked;

faces not tuberculate, abaxial wings 0–1, ± entire, glands 1–2;

beak lateral, erect, 0.2 mm.

heads 0.9–1.5 cm diam;

achenes oblanceoloid, abaxially keeled, 1.2–2.5 × 0.8–1.6 mm, beaked;

faces tuberculate, wings absent, glands 0–1;

beak lateral, erect, 0.1–0.6 mm.