This name is a synonym of Haworthia attenuata (Haw.) Haw..
The record derives from WCSP
(data supplied on 2012-03-26)
which reports it as a synonym (record 297093) with original publication details: Trans. Linn. Soc. London 7: 11 1804.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:529227-1.
This name was in version 1 of The Plant List, record kew-297093.