This name is a synonym of Astranthium robustum (Shinners) DeJong.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 8503D987-1753-46D6-B57A-0E99BF6FDEE9) with original publication details: Field & Lab. 18 158 1950.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:25837-2.
This name was in version 1 of The Plant List, record gcc-7846, and has not been changed.