This name is a synonym of Callitriche fassettii Schotsman.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 330573) with original publication details: Fl. Calif. 2: 436 1936.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:42487-2.
This name was in version 1 of The Plant List, record kew-330573, and has not been changed.