The record derives from TICA
(data supplied on )
which reports it as a synonym (record
CAD11A24-DDC4-42DA-9483-15EBF8EC9451) with original publication details: "C.F.W. Wallroth, Sched. Crit.. 1822" 432 1822.
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.