This name is a synonym of Magnolia virginiana var. australis Sarg..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 117457) with original publication details: Torreya 31: 39 1931.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:149274-2.
This name was in version 1 of The Plant List, record kew-117457, and has not been changed.