Dig deeper at SERNEC, a consortium of southeastern herbaria.
Check out EDDMapS.org to see where this has been reported.
Spermatophytes (seed plants): Angiosperms (flowering plants): Monocots: Commelinids: Poales
Britton & Brown Illus Flora of Northeast US & adjacent Canada (Gleason, 1952)
Manual of the Grasses of the US (Hitchcock & Chase, 1950)