The record derives from WCSP (in review) (data supplied on ) which reports it as a synonym and as an illegitimate name with original publication details: Sci. Rep. Tohoku Imp. Univ., Ser. 4, Biol. 12: 100 1937.
This name record (from WCSP (in review)) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Salix alopochroa in version 1 of The Plant List.