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
Manual of the Grasses of the US (Hitchcock & Chase, 1950)
Setaria verticillata var. verticillata
Manual of the Southeastern Flora (Small, 1933)
No pictures are available at this time.