This name is a synonym of Magnolia macklottii var. beccariana (A.Agostini) Noot..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 117435) with original publication details: Bull. Misc. Inform. Kew 1928: 185 1928.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:554628-1.
This name was in version 1 of The Plant List, record kew-117435, and has not been changed.