This name is a synonym of Cyanthillium cinereum (L.) H.Rob..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 1ACCF849-3964-469B-958E-10997EE8FBB9) with original publication details: 130 1860.
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 Vernonia cinerea in version 1 of The Plant List.