This name is a synonym of Betula pendula var. oycowiensis (Besser) Dippel.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 21548) with original publication details: Prim. Fl. Galiciae Austriac. 2: 289 1809.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:295165-1.
This name was in version 1 of The Plant List, record kew-21548.