This name is a synonym of Wedelia prostrata var. robusta Makino.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 1332D213-FAEA-4F53-8623-DF2EE1783AFF) with original publication details: 1942.
This name was in version 1 of The Plant List, record gcc-130703, and has not been changed.