This name is a synonym of Magnolia gloriensis (Pittier) Govaerts.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 201402) with original publication details: Contrib. U.S. Natl. Herb. 13: 94 1910.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:249118-2.
This name was in version 1 of The Plant List, record kew-201402, and has not been changed.