Flora of North America species comparison

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

submersed and emersed; submersed leaves absent or phyllodial, flattened, to 17 × 2 cm; emersed leaves with petiole triangular, 21–55 cm, blade hastate to sagittate, 2.5–17.5 × 0.6–22 cm, lobes longer than or equal to remainder of blade.

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.

racemes or panicles, of 1–15 whorls, floating or emersed, 1.5–28 × 1.5–15 cm;

peduncles 15–47 cm;

bracts distinct or connate less than ¼ total length, lanceolate to elliptic, 4–34 mm, delicate, not papillose; fruiting pedicels recurved, club-shaped, 0.5–4.2 cm.

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.

2–5 cm diam.;

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

filaments cylindric, longer than anthers, glabrous;

pistillate pedicellate, with or without ring of sterile stamens.

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.

heads 1.2–2.1 cm diam.;

achenes oblanceoloid, not abaxially keeled, 2–4.3 × 0.7–1.5 mm, beaked;

faces not tuberculate, wings absent, glands 1;

beak lateral, horizontal, 0.4–0.8 mm.