Taxonomic synopsis of invasive and native Spartina (Poaceae, Chloridoideae) in the Pacific Northwest (British Columbia, Washington and Oregon), including the first report of Spartina ×townsendii for British Columbia, Canada

Abstract

Five species of the grass genus Spartina are invading salt marshes along the Pacific coast of North America, of which three have been documented in British Columbia, Canada, in only the last decade. A taxonomic synopsis of the two native (S. gracilis, S. pectinata) and five introduced Spartina taxa (S. anglica, S. alterniflora, S. densiflora, S. patens, S. ×townsendii) in the Pacific Northwest is presented to facilitate their identification, including nomenclature, a new taxonomic key, new descriptions for a subset of taxa, and representative specimens. Spartina ×townsendii is newly reported for the flora of British Columbia. The non-coastal species S. pectinata is reported from an urban site in British Columbia, the first confirmed report of the taxon for the province. Lectotypes are newly designated for S. anglica C.E. Hubb., S. maritimasubvar.fallax St.-Yves, and S. cynosuroides f. major St.-Yves.