This name is a synonym of Juncus balticus subsp. mexicanus (Willd. ex Schult. & Schult.f.) Snogerup.
The record derives from IOPI
(data supplied on 2012-03-23)
which reports it as a synonym (record 314828) with original publication details: Revista Sudamer. Bot. 6: 149 1940.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:132090-2.
This name was in version 1 of The Plant List, record kew-314828.