This name is a synonym of Symphyotrichum novi-belgii var. crenifolium (Fernald) Labrecque & Brouillet.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record E4A68411-516D-4715-99E4-D1027B51896E) with original publication details: Rhodora 17 15 1915.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:23440-2.
This name was in version 1 of The Plant List, record gcc-66715.