Scirpus pallidus (Britton) Fernald
Family: Cyperaceae
pale bulrush
[Scirpus atrovirens var. pallidus Willd.]
Scirpus pallidus image
from USDA Plants website  
Scirpus pallidus image
University of Wisconsin-Stevens Point, Robert W. Freckmann Herbarium (UWSP)