This submersed floating plant is widely scattered in "acidic to alkaline" waters of eastern states, except the upper midwest, and most common on the southeastern Coastal Plain (FNA 3). It is easily missed and rarely collected in Ky. Disjunct records from JEFF (DHL, KSNPC) are old (1938, 1940, 1957) and perhaps from adventive or planted populations, but there were large natural ponds in the county before settlement.