This name is a synonym of Ruppia didyma Sw. ex Wikstr..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 286869) with original publication details: Bull. Torrey Bot. Club 42: 359 1915 publ. 1916.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:699837-1.
This name was in version 1 of The Plant List, record kew-286869, and has not been changed.