This name is a synonym of Symphyotrichum laeve var. purpuratum (Nees) G.L.Nesom.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record D3D0D987-E670-407C-BA6D-301E1D692E79) with original publication details: Phytologia 55(6): 377 (1984): 377 1984.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:23616-2.
This name was in version 1 of The Plant List, record gcc-26027, and has not been changed.