This name is a synonym of Euphorbia fendleri Torr. & A.Gray.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 37992) with original publication details: Fl. Rocky Mts. 544 1917.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:55285-2.
This name was in version 1 of The Plant List, record kew-37992.