This name is a synonym of Carduus pycnocephalus subsp. albidus (M.Bieb.) Kazmi.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 224C2C77-444F-40A5-8E1B-A2FD4F8BEA3E) with original publication details: 269 1808.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:188384-1.
This name was in version 1 of The Plant List, record gcc-104197.