Flora of North America species comparison

submersed or floating, rarely emersed; submersed phyllodial, flattened, 30–250 × 0.1–1.5 cm; floating with petiole flattened, to 40 cm, blade linear-ovate to ovate, rarely sagittate, to 3.5 × 0.5 cm; emersed with petiole 5–10 cm, blade linear-ovate to ovate, rarely hastate to sagittate, to 4 × 0.5 cm; stranded plants usually with expanded leaf blades.

emersed;

petiole triangular, 10–40 cm;

blade sagittate, 4.5–10 × 0.2–2 cm, basal lobes ± equal to remainder of blade.

racemes, rarely panicles, of 4–10 whorls, floating to slightly emersed, 15–25 × 5–15 cm;

peduncles 10–200 cm;

bracts connate more than ¼ total length, lanceolate, 110 mm, delicate, not papillose; fruiting pedicels spreading to recurved, cylindric, 1.5–4.5 cm.

racemes, of 2–4 whorls, emersed, 5–14 × 2–4 cm;

peduncles 20–38 cm;

bracts distinct or if connate, then less than ¼ total length, lanceolate, 5–25 mm, not papillose; fruiting pedicels spreading, cylindric, 1.5–3.5 cm.

to 3 cm diam.;

sepals spreading in staminate, erect in pistillate, enclosing flower or fruiting head;

filaments dilated, ± equaling anthers, glabrous;

pistillate pedicellate, without ring of sterile stamens.

to 30 mm diam.;

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

filaments linear, longer than to equal length of anther, glabrous;

pistillate pedicellate, without ring of sterile stamens.

heads 0.7–1 cm diam.;

achenes obovoid, abaxially keeled, 5 × 2.5 mm, beaked;

faces not tuberculate, wings 0–3, ± entire, glands 0–1;

beak lateral, erect, 1 mm.

heads 1–1.8 cm diam.;

achenes cuneate to obovoid, without abaxial keel, 2.4–4 × 1.5–3.8 mm, beaked;

faces not tuberculate, wings 1–3, ± entire, glands 1–2;

beak lateral, obliquely ascending, (0.7–)1–2.1 mm.

= 22.

= 22.