Distribution: Introduced in Pacific County, Washington; common along the Atlantic and Gulf Coasts of the United States.
Habitat: Along the coast in brackish water.
Flowers: August - September
Origin: Introduced from the Atlantic coast of North America
Growth Duration: Perennial
Conservation Status: Not of concern
Strongly rhizomatous perennial, the culms 6-12 dm. tall, glabrous and hollow.
Sheaths open, pubescent at the throat; ligules about 1.5 mm. long, composed chiefly of a fringe of fine, straight hairs; blades 7-15 mm. broad at the base, involute at the tip.
Inflorescence of many spikes, crowded and overlapping, 5-8 cm. long, arranged in a raceme; spikelets 1-flowered, articulate below the glumes, borne in two rows on one side of the rachis; first glume very narrow, acute, 6-9 mm. long, keeled, blunt, 1-nerved; second glume broader and longer, keeled and blunt, exceeding the floret; lemmas keeled, 1-nerved, slightly exceeded by the delicate, 2-nerved palea.
PNW Herbaria: Specimen records of Spartina alterniflora in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Spartina alterniflora checklist entry.
E-Flora BC: Spartina alterniflora atlas page.
CalPhotos: Spartina alterniflora photos.
USDA Plants: Spartina alterniflora information.