Flora of North America species comparison

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.

submersed and floating, sessile, phyllodial, flattened, 50–250 × 0.4–1.5 cm;

rare stranded plants without expanded leaf blades.

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.

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

peduncles to 200 cm;

bracts connate less than or equal to total length, lanceolate, 0.4–0.8 mm, delicate, not papillose; fruiting pedicels spreading to recurved, cylindric, 1.5–4.5 cm.

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.

to 2.8 cm diam.;

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

filaments dilated, ± equaling anthers, glabrous; pistillate pedicellate, without ring of sterile stamens.

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.

heads 0.7–1 cm diam.;

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

faces not tuberculate, wings absent, glands 0–1;

beak lateral, erect, 1 mm.

= 22.