This name is a synonym of Monsonia angustifolia E. Mey. ex A. Rich..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 13900795) with original publication details: J. Bot. Ital. 26: 151 1919.
This name was in version 1 of The Plant List, record tro-13900795, and has not been changed.