Schoenoplectus triqueter

Schoenoplectus triqueter, commonly known as the triangular club-rush, is a species of sedge which lives in temperate Eurasian wetlands, on muddy shores and river margins. It is found across Eurasia, as well as in South Africa, and has been introduced to North America on the west coast. Because of its tolerance of salty habitats, it is considered a halophyte, but plants which were subjected to a high salinity level (10 parts per thousand) in an experiment were noticeably stunted....read more on Wikipedia.