This name is a synonym of Magnolia sieboldii subsp. japonica K.Ueda.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 117879) with original publication details: Bot. Mag. (Tokyo) 40: 339 1926.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:554874-1.
This name was in version 1 of The Plant List, record kew-117879, and has not been changed.