Flora of North America species comparison

septate.

sessile or petiolate;

petiole terete to triangular;

blade with translucent markings absent, linear to obovate, base attenuate to hastate or sagittate, margins entire, apex round to acute.

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.

racemes, panicles, rarely umbels, of 1–17 whorls, erect, emersed or floating, rarely submersed;

bracts coarse or delicate, apex obtuse to acute, smooth or papillose proximally to distally.

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.

unisexual, the proximal rarely with ring of sterile stamens;

staminate flowers pedicellate, distal to pistillate flowers;

pistillate flowers mostly pedicellate, rarely sessile;

bracts subtending pedicels, lanceolate, shorter than pedicels, apex obtuse to acute;

pedicels ascending to recurved;

receptacle convex;

sepals recurved in staminate flowers, recurved to erect in pistillate flowers, often sculptured, herbaceous to leathery;

petals white, rarely with pink spot or tinge, entire;

stamens 7–30;

filaments linear to dilated, glabrous to pubescent;

pistils to 1500 or more, spirally arranged, not radiating in starlike pattern, distinct;

ovules 1;

styles terminal.

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.

without longitudinal ribs, compressed, abaxially keeled or not, abaxial wings often present, lateral wing often present, 1, curved, glands present.

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.

= 11.