This name is a synonym of Lactuca polyclada Boiss..
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 706C2A70-A300-4A29-B280-D59B91DEA811).
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 Chondrilla piestocarpa in version 1 of The Plant List.