Flora of North America species comparison

emersed, rarely floating, petiolate;

blade ovate to elliptic, to 15 × 10 cm.

to 1 m. Flowers chasmogamous;

sepals 1.5–2.5(–6) mm;

petals white, 1–3 mm, margins slightly erose, apex mostly acuminate;

anthers rounded, 0.4–0.6 mm;

style ± curved, 0.2–0.4 mm, ¼ length ovary.

to 1 m. Flowers chasmogamous;

sepals 3–6 mm;

petals white, 3.5–6 mm, margins ± erose, apex obtuse;

anthers ovoid, 0.6–1 mm;

style ± curved, 0.4–0.6 mm, equal to ovary length.

heads 2–4 mm diam;

achenes obliquely ovoid, 1.5–2.2 mm, abaxially rounded, with 1 abaxial groove;

beak ascending.

heads 4.1–7 mm diam;

achenes ovoid, 2.1–3 mm, abaxial keel broadly rounded with 1 median abaxial groove, beak erect or nearly erect.

=14.

= 28.