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Sagittaria platyphylla, the Broad-leaf arrowhead, Delta Arrowhead or Delta Duck-potato, is a plant species native to the eastern United States. The core of its range extends from central Texas to the Florida Panhandle north to southern Illinois. Isolated populations have been reported from Washington State, Missouri, Kansas, Ohio, Kentucky, Pennsylvania, West Virginia, eastern Virginia, North and South Carolina and eastern Georgia, Nuevo León, Michoacán and Panamá. It has also become a noxious weed in Australia. The plant is an emergent aquatic found in ponds, lakes and slow-moving streams.
Sagittaria platyphylla is a perennial herb up to 150 cm tall, producing underground corms (similar to tubers). The plant reproduces by means of stolons as well as seeds. Some leaves are totally submerged, others emergent (raising above the surface of the water). Submerged leaves have flattened petioles but no true blades. Emergent leaves have ovate to elliptical blades up to 17 cm long. Inflorescence is a raceme with 3-9 whorls of flowers. Flowers are white, up to 2 cm in diameter. 
- Australian Weeds Committee, Weed Identification Guide, Sagittaria platyphylla
- Flora of North America v 22.
- BONAP (Biota of North America Project) floristic synthesis, Sagittaria platyphylla
- Correa A., M.D., C. Galdames & M. Stapf. 2004. Catálogo de las Plantas Vasculares de Panamá 1–599. Smithsonian Tropical Research Institute, Panama.
- Smith, Jared Gage. 1894. North American Species of Sagittaria and Lophotocarpus 29.
- Engelmann, Georg in Asa Gray. 1867. Manual of Botany of the Northern United States (ed. 5) 494.
- photo of lectotype of Sagittaria platyphyllaat Missouri Botanical Garden
- Haynes, R. R. & L.B. Holm-Nielsen. 1994. The Alismataceae. Flora Neotropica 64: 1–112.
- Czerepanov, S. K. 1981. Sosudistye Rasteniia SSSR 509 pages. Nauka, Leningradskoe Otd-nie, Leningrad.
- Correll, D. S. & M. C. Johnston. 1970. Manual of the Vascular Plants of Texas i–xv, 1–1881. The University of Texas at Dallas, Richardson
- Wunderlin, R. P. 1998. Guide to the Vascular Plants of Florida i–x, 1–806. University Press of Florida, Gainesville.
- Godfrey, R. K. & J. W. Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States Monocotyledons 1–712. The University of Georgia Press, Athens