Flora of North America species comparison

septate or not septate.

emersed;

petiole 5-winged, 19–85 cm;

blade sagittate, 3–19 × 2.5–11 cm, basal lobes ± 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, of 5–12 whorls, emersed, 10–29 × 3–5 cm;

peduncles 25–105 cm;

bracts distinct or if connate, then less than ¼ total length, lanceolate, 7–30 mm, papery, not papillose; fruiting pedicels spreading to ascending, cylindric, 0.3–2.3 cm.

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

to 3 cm diam.;

sepals recurved to spreading, not enclosing flower or fruiting head;

filaments cylindric, longer than anthers, glabrous; pistillate pedicellate, 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 cm diam.;

achenes obovoid, without abaxial keel, 2.1–3.2 × 1.4–2.3 mm, beaked;

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

beak lateral, strongly recurved, 4–17 mm.

= 22.