This name is a synonym of Centranthus longiflorus subsp. junceus (Boiss. & Heldr.) I.Richardson.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Bull. Soc. Sci. Nancy III, 9: 350 1908.
This name was in version 1 of The Plant List, record kew-2709047.