Solidago canadensis subsp. canadensis is a synonym of Solidago canadensis L.
This name is a synonym of Solidago canadensis L..
The record derives from TICA (data supplied on 2012-02-11 ) which reports it as a synonym (record C19DE792-FCA2-4F64-9D78-465CDF0E2269).
This name record (from TICA) 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 Solidago canadensis in version 1 of The Plant List.