The male flowers are borne below the female spikes. The leaves are very narrow. Swamps, wet meadows. Tufted annual with fibrous roots. Ovate, obtuse, shorter than the perigynia.
Achenes ovate, flattened, smooth.
The achenes are eaten by waterfowl. Although the National Wetlands Inventory lists area 2 in the range of this species, there is no evidence that it occurs in the southeastern United States.