Flora of North America species comparison

septate or not septate.

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.

basal, submersed, floating, or emersed, sessile or petiolate, sheathing proximally;

blade with translucent markings of dots or lines present or absent, basal lobes present or absent;

venation reticulate, primary veins parallel from base of blade to apex, secondary veins reticulate.

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.

scapose racemes or panicles, rarely umbels, erect, rarely floating or decumbent, whorled (forming racemes) or whorls branching (forming panicles), bracteolate.

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.

bisexual or unisexual, if unisexual, staminate and pistillate on same or different plants, hypogynous, subsessile to long-pedicellate;

sepals persistent, 3;

petals deciduous, 3, delicate;

stamens 0, 6, 9, or to 30, distinct;

anthers 2-loculed, dehiscing longitudinally;

pistils 0 or 6–1500 or more, distinct or coherent proximally, 1-loculed;

placentation basal;

ovules1–2.

achenes or follicles.

embryo U-shaped;

endosperm absent in mature seed.

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.