This name is a synonym of Atriplex argentea var. expansa (S.Watson) S.L.Welsh & Reveal.
The record derives from WCSP (in review)
(data supplied on 2012-03-23)
which reports it as a synonym with original publication details: Proc. Amer. Acad. Arts 9: 116 1874.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:26321-2.
This name was in version 1 of The Plant List, record kew-2665257, and has not been changed.