This plant is growing in the River Roding by Wanstead Park, and is difficult to access for positive identification. It is likely that a more experienced botanist would be able to do so at a distance, but for the time being it is sufficient to say that it is a Schoenoplectus species.

S. tabernaemontani, Grey Clubrush, is recorded as being present in Wanstead Park area in the "Flora of Essex" (Jermyn) and it is possible that it is this species we have here.