This name is a synonym of Glyceria fluitans (L.) R.Br..
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym and as an invalid name (record 407872) with original publication details: Enum. Pl. 1: 367 1833.
This name was in version 1 of The Plant List, record kew-407872.