Ammophila arenaria is a species of grass known by the common names European marram grass and European beachgrass. It is native to the coastlines of Europe and North Africa where it grows in the sands of beach dunes. It is a perennial grass forming stiff, hardy clumps of erect stems up to 1.2 metres (3.9 ft) in height. It grows from a network of thick rhizomes which give it a sturdy anchor in its sand substrate and allow it to spread outward.
European Beachgrass is also recognised as one of the most problematic noxious weeds of coastal California. This sand-adapted grass was introduced to the beaches of western North America during the mid-19th century to provide stabilization to shifting sand dunes. It grew readily and it can now be found from California to British Columbia. The grass is invasive in the local ecosystems, forming dense monotypic stands that crowd out native vegetation, reduce species diversity of native arthropods, and cover vital open stretches of sand used for nesting by the threatened Western Snowy Plover.