This name is a synonym of Jacobaea maritima (L.) Pelser & Meijden.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record AC4E1112-D59D-4EBC-8751-0D46CF6BC8FD).
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 Senecio cineraria in version 1 of The Plant List.