This name is a synonym of Arctium minus f. tomentosum (A. Gray) Moldenke.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50326664) with original publication details: Manual (ed. 6) 295 1890.
This name was in version 1 of The Plant List, record tro-50326664, and has not been changed.