Flora of North America species comparison

submersed, phyllodial, lenticular, to nearly terete, 12–53 × 0.3–0.7 cm;

rare stranded plants without expanded leaf blades.

emersed;

petiole triangular, 15–54 cm;

blade lanceolate to ovate, 5–20 × 1–10.5 cm.

racemes, of 2–7 whorls, floating or emersed, to 16 × 4 cm;

peduncles 13.5–28 cm;

bracts connate more than ¼ total length, ovate to lanceolate, 1.5–2 mm, delicate, not papillose; fruiting pedicels spreading to reflexed in flower and fruit, cylindric, 1.5–6.5 cm.

racemes, rarely panicles, of 2–11 whorls, emersed;

bracts scarcely connate proximally, linear to lanceolate, 10–30 mm, delicate, not papillose; fruiting pedicels spreading to ascending, cylindric, 1.5–3.5 cm.

1.5–5 cm diam.;

sepals spreading in staminate, appressed to spreading in flower and fruit in pistillate, often enclosing flower or fruiting head;

filaments dilated, longer than anthers, glabrous;

pistillate pedicellate, without ring of sterile stamens.

to 23 mm diam.;

sepals recurved, not enclosing flower or fruiting head;

filaments linear, shorter than anthers, glabrous;

pistillate pedicellate, without ring of stamens.

heads 0.4–0.6 cm diam;

achenes oblanceoloid to obovoid, not abaxially keeled, 1.5 × 1 mm, beaked;

faces not tuberculate, wings absent, glands absent;

beak lateral, erect, 1.1 mm.

heads 0.8–1.2 cm diam;

achenes cuneate-obovoid, abaxially keeled, 1.5–2.1 × 0.8–1.5 mm, beaked;

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

beak lateral, horizontal or incurved, 0.1–0.2 mm.