This name is a synonym of Echinocereus engelmannii var. munzii (Parish) Pierce & Fosberg.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Bull. S. Calif. Acad. Sci. 25: 48 1926.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:53149-2.
This name was in version 1 of The Plant List, record kew-2712125, and has not been changed.