This name is a synonym of Aster ovatus var. microcephalus (Miq.) Mot.Ito & Soejima.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 0469EAB0-81CF-4A75-BFAD-FA78B20785B8).
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 microcephalus in version 1 of The Plant List.