Dig deeper at SERNEC, a consortium of southeastern herbaria.
Its elongate, tapering, seed beak (1.5-2mm long) is distinctive. Read more at Vascular Plants of North Carolina.
Spermatophytes (seed plants): Angiosperms (flowering plants): Monocots: Commelinids: Poales
Rhynchospora (Cyperaceae) of South Carolina and the Eastern United States (McMillan, 2007)
Manual of the Southeastern Flora (Small, 1933)