This name is a synonym of Betula platyphylla subsp. kamtschatica (Regel) Vorosch..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 21589) with original publication details: Bot. Zhurn. (Moscow & Leningrad) 70: 1064 1985.
This name was in version 1 of The Plant List, record kew-21589.