This name is a synonym of Metrosideros diffusa (G.Forst.) Sm..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym and as an illegitimate name (record 123760) with original publication details: Suppl. Pl. 342 1782.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:598009-1.
This name was in version 1 of The Plant List, record kew-123760, and has not been changed.