This name is a synonym of Micranthocereus polyanthus (Werderm.) Backeb..
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Repert. Spec. Nov. Regni Veg. Sonderbeih. C t. 43 1932.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:274256-2.
This name was in version 1 of The Plant List, record kew-2709547, and has not been changed.