This name is a synonym of Betula utilis var. occidentalis (Kitam.) Ashburner & A.D.Schill..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 3600349) with original publication details: ? .
This name was in version 1 of The Plant List, record tro-3600349, and has not been changed.