This name is a synonym of Thesium humile var. maritima (N.D.Simpson) F.M.Saad.
The record derives from WCSP (in review)
(data supplied on 2012-03-26)
which reports it as a synonym with original publication details: Techn. Sci. Serv. Bull. 93: 36 1930.
This name record (from WCSP (in review)) 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 Thesium humile in version 1 of The Plant List.