This name is a synonym of Haworthia coarctata f. greenii (Baker) M.B.Bayer.
The record derives from WCSP
(data supplied on 2012-03-26)
which reports it as a synonym (record 312611) with original publication details: Mem. Soc. Brot. 2: 87 1943.
This name was in version 1 of The Plant List, record kew-312611, and has not been changed.