This name is a synonym of Carduus nyassanus subsp. kikuyorum (R.E.Fr.) C.Jeffrey.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 23E411E2-14A5-4A02-9062-CBCAA35F3BB7) with original publication details: Acta Horti Berg. 8: 26 (1923) 26 1923.
This name was in version 1 of The Plant List, record gcc-66067.