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 (record 123612) with original publication details: Fl. Ins. Austr. 37 1786.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:597918-1.
This name was in version 1 of The Plant List, record kew-123612, and has not been changed.