This name is a synonym of Symphyotrichum lanceolatum var. lanceolatum .
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 8B51C82E-43A5-4429-B7EF-FC33E05EEE1B).
This name record (from TICA) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Aster lamarckianus in version 1 of The Plant List.