This name is a synonym of Plectocephalus varians (A.Rich.) C.Jeffrey in Cufod..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record E97EC4FA-094B-485E-9656-572F047B1888).
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 abyssinica in version 1 of The Plant List.