This name is a synonym of Cyanus triumfettii subsp. axillaris (Čelak.) Štěpánek.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 699A790A-156D-4096-A2BA-533FC689105D).
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 axillaris in version 1 of The Plant List.