Ciaran @Tapirlord . A sedge ... (non–climbing) .
Eg. Showing here, stems triangular in cross-section. Showing here, not a climber, well grown leafy culms free standing . (Hence not _Freycinetia_ genus aka 'climbing pandans') .
it should now be listed (I have tried to add it): but it won't be under Other Freshwater Plants category, as that applies to non-woody species: check under other Trees.