Sagittaria montevidensis subsp. montevidensis
Herbs, perennial, not stranded by low tide. Leaves submersed and emersed; submersed leaves sessile, blade linear; emersed petiolate, blade hastate to sagittate. Inflorescences of 1–15 whorls, floating or emersed; bracts connate. Flowers: pistillate without ring of sterile stamens; petals with purple spot at base.
Phenology: Flowering summer–fall (Jul–Oct).
Habitat: Wet ditches, mud flats of rivers
Elevation: 0–10 m
Introduced; Ala., Fla., Ga., c, s South America
Sagittaria montevidensis subsp. montevidensis apparently is native to South America. It has been introduced along the coast of the Gulf of Mexico.