See also:
http://plantsoftheworldonline.org/taxon/urn:lsid:ipni.org:names:60456000-2 (calls it Vincetoxicum)
and note from @milkweedguy:
"ITIS [which calls it Vincetoxicum] is the most authoritative source for nomenclature of North American plants. The New Manual of Vascular Plants of Northeastern United States and Adjacent Canada and Flora of North America will both use this nomenclature."
Unintended disagreements occur when a parent (B) is
thinned by swapping a child (E) to another part of the
taxonomic tree, resulting in existing IDs of the parent being interpreted
as disagreements with existing IDs of the swapped child.
Identification
ID 2 of taxon E will be an unintended disagreement with ID 1 of taxon B after the taxon swap
If thinning a parent results in more than 10 unintended disagreements, you
should split the parent after swapping the child to replace existing IDs
of the parent (B) with IDs that don't disagree.