This name is a synonym of Xanthium orientale subsp. riparium (Čelak.) Greuter.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 75B6C798-FCCD-42DA-88D8-7280E674B6C4) with original publication details: 186 1871.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:50426527-2.
This name was in version 1 of The Plant List, record gcc-54999.