Flora of North America species comparison

submersed and emergent;

petiole triangular, 11.5–35 cm;

blade elliptic to ovate, 25–56 cm.

mostly submersed, rarely emersed, sessile, phyllodial, flattened to lenticular, 5–30 × 0.2–0.5 cm.

racemes or panicles, of 4–10 whorls, emersed, 8–25 × 5–36 cm;

peduncles to 76 cm;

bracts connate ¼ total length, lanceolate, 4–8 mm, papillose; fruiting pedicels ascending to spreading, cylindric, 1–4.5 cm.

racemes, of 2–5 whorls, emersed, 1.5–8 × 1–7 cm;

peduncles 1–2.5 cm;

bracts connate more than or equal to ¼ total length, lanceolate, 0.5–1.5 mm, delicate, not papillose; fruiting pedicels spreading, cylindric, 0.6–2.5 cm.

to 3 cm diam.;

sepals appressed to spreading;

filaments slightly dilated, shorter than anthers, glabrous;

pistillate pedicellate, without ring of sterile stamens.

to 2.5 cm diam.;

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

filaments dilated, shorter than anthers, minutely tomentose;

pistillate pedicellate, without ring of sterile stamens.

heads 0.7–1 cm diam.;

achenes obovoid, abaxially keeled, 1.2–1.5 × 0.7–1.1 mm, beaked;

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

beak lateral, erect, 0.1–0.3 mm.

heads 0.5 cm diam;

achenes obovoid-triangular, abaxially keeled, 2 × 1 mm, beaked;

faces tuberculate, wings 1, scalloped or toothed, glands 0–1;

beak lateral, incurved-erect, 0.3 mm.