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.

submersed and emersed; submersed sessile, phyllodial, flattened, to 26 × 0.5 cm; emersed with petiole ± triangular, 21–70.5 cm, blade linear-ovate to ovate, 4.6–16.4 × 0.7–6.1 cm.

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 3–9 whorls, emersed, 2.5–10 × 2–4.5 cm;

peduncles 22–60 cm;

bracts connate more than ¼ total length, lanceolate, 3–5.5 mm, delicate, not papillose; fruiting pedicels spreading to recurved, cylindric, 0.5–3 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 1.8 cm diam.;

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

filaments dilated, longer than anthers, pubescent;

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 0.7–1.2 cm diam.;

achenes oblanceoloid, not abaxially keeled, 1.2–2 × 0.8–1.2 mm, beaked;

faces tuberculate, wings absent, glands absent;

beak lateral, horizontal to erect, 0.3–0.6 mm.

= 22.

= 22.