American Bur Reed (Sparganium americanum Nutt.)

An erect, grass-like, aquatic sedge plant with zig-zag stalks bearing ball-like heads of tiny green flowers. Native to the Eastern United States. 
The Bur-reeds represent an important group of emergent plants that are partly in and partly out of the water; they frequently form dense stands along the edges of shallow lakes and ponds. The seeds are eaten by waterfowl and marsh birds, and muskrats feed on the entire plant.