This name is a synonym of Carduus pycnocephalus L..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 4997453E-B96A-4A51-ABA2-DB15619E687F).
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 Carduus pycnocephalus in version 1 of The Plant List.