Sagittaria filiformis, the threadleaf arrowhead, is a perennial aquatic plant growing up to tall. Some leaves are thread-like, entirely underwater, but others are narrowly ovate or lanceolate and floating on the surface.Smith, Jared Gage. 1894. North American Species of Sagittaria and Lophotocarpus 20, pl. 15, figs 5-8, Sagittaria filiformis
The species is native to the eastern United States, from Maine south to Florida and Alabama. It occurs in flowing streams in the northern part of its range, but more stagnant waters such as marshes and swamps in the South.
References
External links photo of herbarium specimen at Missouri Botanical Garden, holotype of Sagittaria filiformis, collected in Alabama photo of herbarium specimen at Missouri Botanical Garden, Sagittaria filiformis, collected in Florida Center for Aquatic and Invasive Plants, University of Florida Go Botany, New England Wildflower Society Maine Department of Agriculture Conservation and Forestry, Maine Natural Areas Program,