Sagittaria australis

Sagittaria australis, the Appalachian arrowhead or longbeak arrowhead, is a plant species native to much of the eastern part of the United States, from Louisiana to Iowa to New York State to Florida, mostly between New Jersey and Mississippi with scattered locations elsewhere in the range.
It is an emergent aquatic, growing in swamps and along the edges of lakes and ponds. It is sometimes sold as an ornamental to be cultivated in aquaria or garden ponds.
"Sagittaria australis" is a perennial herb up to 130 cm (50 inches) tall. It is unusual in genus in having a 5-winged petiole. Flowers are up to 3 cm (1.2 inches) in diameter, white, producing an achene with a recurved beak.