Scirpus caespitosus

About

Eleocharis palustris, the common spike-rush, creeping spike-rush or marsh spike-rush, is a species of mat-forming perennial flowering plants in the sedge family Cyperaceae. It grows in wetlands in Europe, North Africa, northern and central Asia and North America. Eleocharis palustris is not easily distinguished from other closely related species and is extremely variable worldwide itself. The species epithet palustris is Latin for "of the marsh" and indicates its common habitat.

Summary from Wikipedia