This name is a synonym of Magnolia kobus DC..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym and as an invalid name (record 117781) with original publication details: Bot. Mag. (Tokyo) 43: 386 1929.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:554809-1.
This name was in version 1 of The Plant List, record kew-117781, and has not been changed.