This name is a synonym of Helianthus nuttallii subsp. rydbergii (Britton) R.W.Long.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 47CD5AC5-F270-4843-A0F8-20242B1585AB) with original publication details: 1901.
This name was in version 1 of The Plant List, record gcc-17394, and has not been changed.