This name is a synonym of Betula pubescens var. pumila (L.) Govaerts.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 21667) with original publication details: Deut. Dendrol. 109 1893.
This name was in version 1 of The Plant List, record kew-21667, and has not been changed.