Common arrowhead brightens the view on a bayou shore in the Neponset River floodplain. Arrowheads belong to water-plantain family, which consists entirely of water-loving plants. Arrowheads form a large genus with the center of diversity in North America. A few species may grow together in one place, and they are not necessarily easy to tell apart. Common arrowhead is a species with an enormous area that covers nearly all of North America from Quebec to California and extends to Central and South America.