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.

emersed, sessile, phyllodial, linear to lanceolate, flattened, 15–25(–40) × 1.5–4 cm, or petiole triangular, 15–50 cm, blade linear to elliptic-lanceolate, 4–10 × 0.3–2 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.

racemes, of 3–6 whorls, 1.5 × 4 cm;

peduncle 20–60 cm;

bracts connate greater than or equal to ¼ total length, ovate, 4–10 mm, nearly scarious, not papillose; fruiting pedicels spreading, cylindric, 0.8–3 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 0.8 cm diam.;

sepals recurved to spreading, not enclosing flower;

filaments dilated, exceeding anthers in length, pubescent; 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 1.2–2 cm diam.;

achenes cuneate-obovoid, abaxially keeled, 2.5–3 × 1.4–1.8 mm, beaked;

faces not tuberculate, wings 1, ± entire, glands absent;

beak ascending to horizontal, 0.4–0.7 mm.