Flora of North America species comparison

nodal, never tuberous.

leafy, creeping or floating, not bulbous-based, without bulbils.

cauline, simple, petiolate;

blade undivided or 3-lobed, much longer than wide, margins entire.

axillary, solitary flowers.

pedicellate (pedicels naked or leafy);

sepals deciduous soon after anthesis, 3;

petals 7-11, white or reddish;

nectary scale attached on 3 sides for at least half its length, forming pocket (sometimes mouth of pocket prolonged as short flap), glabrous, free margin entire;

style present.

achenes, 1-locular, 4.2-5.2 mm;

achene body oblong-lenticular, 1.3-1.7 times as wide as thick, prolonged beyond seed as corky distal appendage;

wall thick, smooth;

margin low corky band;

beak much shorter than achene body.