Publication: Fl. Gall. 719. 1807.
Origin: Introduced from the Atlantic coast of North America
selected vouchers: WTU
Notes: FNA25: "partina alterniflora is found on muddy banks, usually of the intertidal zone, in eastern North and South America, but it is not known from Central America. In addition, it has become established on the west coast of North America, England, southeastern France, and China. It hybridizes with S. maritima in Europe, with S. pectinata in Massachusetts, and with S. foliosa in California.
The rhizomes and scales of S. alterniflora have large air spaces, presumably an adaptation to the anaerobic soils of its usual habitat. Decaploid plants tend to be larger than octoploids, but they cannot be reliably distinguished without a chromosome count.
Spartina alterniflora is considered a serious threat to coastal ecosystems in Washington and California. It out-competes many of the native species in these habitats and frequently invades mud flats and channels, converting them to marshlands. Pure S. alterniflora grows within the lower elevational marsh zones in its native range but, in San Francisco Bay, its hybrids with S. foliosa grow both below and above the range of that species."