Spike Rush (Eleocharis spp.)
Emergent Spike Rush (photo Don Yurewicz)
Some species of spike rush are erect and emergent (see photo), while others are more grass-like and submergent (bottom two photos). The emergent species are easily identifiable by brown spiked seed heads at the top of the plant. They are often eaten by birds and may not be present. (excerpted from "Aquatic Plants Aquatic Plants & Algae of New Hampshire’s Lakes and Ponds).
The emergent species of spike rush are common in shallow perimeter of the lake.