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 or submersed, sessile, phyllodial, nearly terete; emersed, to 60 × 0.15–0.7 cm; submersed, 3.5–18.5 × 0.15–0.4 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 1–4 whorls, emersed, 2.5–4 × 2.5–6 cm;

peduncles 10–80 cm;

bracts connate more than or equal to total length, subulate, 2–3 mm, delicate, not papillose; fruiting pedicels obliquely ascending, filiform, 1 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 1.5 cm diam.;

sepals recurved, not enclosing flower;

filaments dilated, ± equaling 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 0.6–1 cm diam.;

achenes obovoid-cuneate, abaxially keeled, 2–3 × 1.2–1.5 mm, beaked;

faces not tuberculate, wings absent, glands 1–2;

beak erect to horizontal, 0.3–0.4 mm.

= 22.

= 22.