This name is a synonym of Magnolia wilsonii (Finet & Gagnep.) Rehder.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 117638) with original publication details: J. Roy. Hort. Soc. 75: 159 1950.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:554734-1.
This name was in version 1 of The Plant List, record kew-117638.