This name is a synonym of Centaurea castellana Boiss..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 26BA2E1F-EEEB-4F1A-890C-ED0CE7548CC5).
This name record (from TICA) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Centaurea castellana in version 1 of The Plant List.