This name is a synonym of Brassica repanda subsp. saxatilis (DC.) Heywood.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Syst. Nat. 2: 598 1821.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:279363-1.
This name was in version 1 of The Plant List, record kew-2682271, and has not been changed.