This name is a synonym of Sonchus asper (L.) Hill.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 8F7C505E-65A3-4E8C-BB97-9FD18B703172).
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 Sonchus fallax in version 1 of The Plant List.