Flower:

One to a few flowers on a stout, usually naked stem rising out of the water. Flowers are ½ to 1 inch across with 5 (occasionally more) shiny yellow petals, numerous orange to yellow stamens around a green center, and 5 spreading yellowish green sepals that are shorter than the petals.

Leaves and stem:

Most of the plant is submerged, except when stranded in mud. Leaves are greatly variable but mostly semi-circular to kidney shaped in outline, ½ to 4 inches long and wide, simple, divided into many narrow segments and can appear to be compound.

Submerged leaves are more finely divided than those above the surface of the water, most palmately lobed but some pinnately lobed. Stems are stout but weak, smooth and hollow.

Fruit:

The center expands to an oval seed head about 1/3 inch long. Seeds are smooth and have a straight beak.

Notes:

A similar aquatic species is Small Yellow Water Crowfoot (Ranunculus gmelinii), which has smaller flowers (less than ½ inch), and smaller leaves that are typically wider than long and less finely divided.