This name is a synonym of Monanthotaxis caesia var. elongata (Ghesq. ex Cavaco & Keraudren) Verdc..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 1600870) with original publication details: Bull. Mus. Hist. Nat. (Paris) 29: 352 1957.
This name was in version 1 of The Plant List, record tro-1600870, and has not been changed.