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.

submersed, phyllodial, lenticular, 5–40 ´ 0.1–0.4 cm, or rarely floating;

petiole terete, 2.4–4 cm;

blade linear-lanceolate to ovate, 1–2.5 ´ 0.3–1.5 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 2–7 whorls, floating, 2–11 ´ 1.5–4.5 cm;

peduncles 5–40 cm;

bracts connate more than ¼ total length, subulate, 1.5–4.2 mm, delicate, not papillose; fruiting pedicels recurved, cylindric to club-shaped, 0.2–1.1 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.

0.4–1.2 cm diam.;

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

filaments dilated, longer than anther, glabrous;

pistillate pedicellate, occasionally with ring of sterile stamens.

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 0.55–0.8 cm diam.;

achenes oblanceoloid, abaxially keeled, 2 ´ 1.5 mm, beaked;

faces not tuberculate, wings 1–2, crenate, glands 0–1;

beak lateral, erect, 0.2–0.4 mm.

= 22.