This name is a synonym of Symphyotrichum lateriflorum var. flagellare (Shinners) G.L.Nesom.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record BED98E45-64A0-456A-B68B-208CDBDA296B) with original publication details: Field & Lab. 21 158 1953.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:23640-2.
This name was in version 1 of The Plant List, record gcc-17633, and has not been changed.