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 4558445B-6DAF-4F43-A415-8AF531FB4054) with original publication details: Field & Lab. 21 157 1953.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:23635-2.
This name was in version 1 of The Plant List, record gcc-57986, and has not been changed.