This name is a synonym of Helianthus pauciflorus subsp. subrhomboideus (Rydb.) O.Spring & E.E.Schill..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record C995D3A6-7326-4F0D-853F-1F1D522FC974) with original publication details: 419 1900.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:278040-2.
This name was in version 1 of The Plant List, record gcc-16841, and has not been changed.