This name is a synonym of Euphorbia stygiana H.C.Watson.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym and as an illegitimate name (record 80837) with original publication details: Fl. Azor. 27 1844.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:347317-1.
This name was in version 1 of The Plant List, record kew-80837.