Flora of North America species comparison

erect or ascending from caudices, not rooting nodally, distally glabrous or brown-pilose, not bulbous-based.

floating or prostrate, glabrous, rooting at proximal nodes.

basal leaves seldom present, cauline leaf blades semicircular to reniform, 1-6x-lobed, parted, or dissected 1.2-7.3 × 1.9-10.8 cm, base truncate or cordate, segment margins entire or crenate, apex rounded to filiform.

reniform to broadly triangular in outline, 3-foliolate or deeply 3-parted, 1-4 × 1.6-4.4 cm, leaflets or segments 1-2x-parted, ultimate segments elliptic to oblanceolate or almost linear, margins entire or occasionally with 1-2 teeth, apex rounded to obtuse.

receptacle glabrous or brown-pilose;

sepals spreading, 7-12 × 4-9 mm, brown-pilose;

petals initially white, usually becoming red with age, 9-15 × 7-14(-18) mm.

receptacle sparsely hispid;

sepals 5, spreading or weakly reflexed, 5-7 × 3-6 mm, glabrous;

petals 5-6(-14), 7-12 × 5-9 mm;

nectary scale variable, crescent-shaped, funnel-shaped, or flaplike;

style 0.8-1.2 mm.

ovoid, 8-10 × 7-8 mm;

achenes 1.8-2.2 × 1.6-2.2 mm, glabrous;

beak lanceolate, straight, 1-1.8 mm.

roots absent.

heads hemispheric, 5-8 × 7-16 mm;

fruit wall smooth, not veined, loose but not inflated, winged along suture, fruits winged achenes;

achenes 2.6-3 × 1.4-2 mm, glabrous;

beak persistent, lanceolate, 0.8-2.3 mm.

= 32.