Schoenoplectus californicus (Cyperaceae) in New Zealand

Ecological, taxonomic, and physiological notes are given on Schoenoplectus californicus. This species has been recently recorded as naturalised in New Zealand, despite the possibility that it may have been present in the country since c. 1900 and overlooked through confusion with the indigenous S. tabernaemontani. This large aquatic reed currently occupies extensive areas along the Wairoa and Waikato Rivers on the west coast of the northern North Island, and has also been planted in artificial wetlands. It grows vigorously and produces viable seed. Unknown factors may be restricting its spread.