Sagittaria longiloba is a species of flowering plant in the water plantain family known by the common name longbarb arrowhead and Gregg arrowhead. It is native to the south-central and southwestern United States (Texas, New Mexico, Oklahoma, Kansas, Nebraska, Arizona and California) plus Mexico, Venezuela and Nicaragua. It is also reportedly naturalized in the western Himalayas of India and Bhutan. It grows in slow-moving, stagnant, and ephemeral water bodies such as ponds and small streams, and sometimes disturbed and cultivated habitat such as rice fields and irrigation ditches.