Alisma parviflorum

About

Alisma subcordatum, the American water plantain, is a perennial aquatic plant in the water-plantain family (Alismataceae). This plant grows to about 3 feet in height with lance to oval shaped leaves rising from bulbous corms with fibrous roots. Any leaves that form underwater are weak and quick to rot; they rarely remain on adult plants. A branched inflorescence with white to pink 3-petaled flowers blooms from June to September. The seeds are eaten by waterfowl and upland birds. Native Americans dried and ate the submerged rootlike structures. The species name subcordatum means "almost heart-shaped".

Summary from Wikipedia