This name is a synonym of Callitriche palustris subsp. subanceps (Petrov) Kuvaev.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 31526) with original publication details: Bot. Not. 128: 516 1975 publ. 1976.
Full publication details for this name can be found in IPNI: http://ipni.org/urn:lsid:ipni.org:names:875462-1.
This name was in version 1 of The Plant List, record kew-31526, and has not been changed.