This name is a synonym of Phoradendron flavens var. orbiculatum (Engelm.) Engelm..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50130885) with original publication details: Mem. Amer. Acad. Arts, n.s. 4: 59 1849.
This name was in version 1 of The Plant List, record tro-50130885.