Flora of North America species comparison

submersed or emersed; submersed leaves phyllodial, angled abaxially, flattened adaxially, 6.4–35 × 0.5–4 cm; emersed with petiole triangular, 6.5–17 cm, blade linear to linear-oblanceolate, 2.5–17.4 × 0.2–4 cm.

emersed, sessile, phyllodial, lenticular, or with petiole triangular, to 53 cm, blade lance-elliptic, 11–18 × 1.5–4.5 cm.

racemes or panicles, of 1–12 whorls, emersed, 2.5–21 × 1–8 cm;

peduncles 6.5–29.7 cm;

bracts connate more than to equal to ¼ total length, broadly subulate to lanceolate, 20–50 mm, coarse, not papillose; fruiting pedicels spreading, cylindric, 0.5–5 cm.

racemes, of 3–9 whorls, emersed, 2–13.5 × 3–6 cm;

peduncles to 75 cm;

bracts connate more than ¼ total length, lanceolate, 5–8 mm, delicate, not papillose; fruiting pedicels recurved, cylindric, 0.5–2.5 cm.

to 2.3 cm diam.;

sepals recurved to spreading, not enclosing flower;

filaments dilated, shorter than anthers, pubescent;

pistillate flowers pedicellate, without ring of sterile stamens.

to 3.5 cm diam.;

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

filaments club-shaped, longer than anthers, pubescent;

pistillate pedicellate, without ring of sterile stamens.

unknown.

heads 0.6–1.5 cm diam.;

achenes oblanceoloid, without abaxial keel, 1.5–2.8 × 1.1–1.5 mm, beaked;

faces not tuberculate, abaxial wings 0–1, ± entire, glands 1–2;

beak lateral, erect, 0.2 mm.

heads 0.7–1.2 cm diam.;

achenes oblanceoloid, abaxially keeled, 2–3 × 1.4–2.1 mm, beaked;

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

beak lateral, erect, 0.2–0.6 mm.