Mystery Grass

Whenever I visit Mount Douglas Park I always visit a small swampy area because it has such a grand stand of Skunk Cabbage and to see the wonderful cuneiform of deer hoofprints in the black mud. On my last visit however, what drew my attention were stands of this grass with their striking flower heads. I'm guessing these are male and female flowers but I have no idea. Nor do I know what this grass is called. Any ideas?