This name is a synonym of Phoradendron leucarpum subsp. macrophyllum (Engelm.) J.R. Abbott & R.L. Thompson.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50245902) with original publication details: Trees and Shrubs of the Southwest Deserts 286 1981.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:1151997-2.
This name was in version 1 of The Plant List, record tro-50245902.