This name is a synonym of Arabis pubescens subsp. decumbens Ball.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Bull. Soc. Hist. Nat. Afrique N. 15: 72 1924.
This name was in version 1 of The Plant List, record kew-2645526, and has not been changed.