Dig deeper at SERNEC, a consortium of southeastern herbaria.
Check out EDDMapS.org to see where this has been reported.
Read more about Black Swallow-wort at Vascular Plants of North Carolina.
Spermatophytes (seed plants): Angiosperms (flowering plants): Eudicots: Core Eudicots: Asterids: Lamiids: Gentianales
Britton & Brown Illus Flora of Northeast US & adjacent Canada (Gleason, 1952)
Black Swallow-wort, Dog-Strangling Vine