Flower:

Flowers are 1½ to 3 inches across with up to 15 white petals and 30 to 45 yellow stamens surrounding a saucer-shaped disk in the center. Light green sepals about as long as the petals are at the back. The sepals and outer rows of petals are whorled in groups of 4. Flowers are single, floating on the water's surface at the end of a long naked stem, closing up at night and may only be open a few hours a day.

Leaves and stems:

Leaves are 1½ to 6 inches long, toothless and hairless, broadly elliptic in outline with a round tip and a pair of lobes forming a deep “V” at the base. The basal lobes are about as long as the remainder of the blade, or a little less. The upper surface is green and the lower green to deep purple. Leaves float on the water's surface at the end of a long, hairless stalk arising from a stout rhizome.

Fruit:

Fruit is round and berry-like, containing oval seeds about 1/16 inch long.

Notes:

Small White Water-lily is a circumboreal species, more widely distributed in Canada and only present in a handful of northern US states. Uncommon to rare in its North American range, Minnesota has more occurrences than other US states, with around 30 known locations in our northern counties. According to the DNR, it seems to have a liking for waters impounded by beaver dams. It's been listed as a Minnesota Threatened species since 1984; threats include disturbances such as herbicide applications, wild rice management, and boat wakes, as well as water warming, siltation and oxygen depletion. A similar species is the related American White Water-lily (Nymphaea odorata), which has flowers twice the size with twice as many petals, and leaves more than twice the size that are rounder in outline with a much narrower gap between the 2 basal lobes. Another similar species, N. tetragona, is not known to be in the lower 48 states but is just to our north in Canada; it is most easily distinguished by a distinct pair of small lobes at the base of the sepals and having up to 70 yellow-orange stamens. N. leibergii sometimes goes by synonym Nymphaea tetragona subsp. leibergii.