This name is a synonym of Juncus balticus subsp. littoralis (Engelm.) Snogerup.
The record derives from IOPI
(data supplied on 2012-03-23)
which reports it as a synonym (record 315773) with original publication details: Monogr. Gen. Junci 13 1801.
This name was in version 1 of The Plant List, record kew-315773, and has not been changed.