Scirpus echinatus

About

Cyperus echinatus, commonly called globe flatsedge, is a species of plant in the sedge family. It is native to much of the eastern United States, primarily in the lower Mississippi Valley and the lowland plain east of the southern Appalachians, with scattered populations in Florida and as far north as Wisconsin and the Adirondacks. Additional isolated populations occur in southern Mexico. It is found in a variety of sunny, often mesic habitats.

Summary from Wikipedia