Leymus arenaria is a grass species that is commonly known as the sand ryegrass or the coast ryegrass. It is a perennial species that can grow up to 4 feet tall and is widely found in coastal sand dunes, salt marshes, and other sandy locations. The plant has several other synonyms, including Leymus mollis, Ammophila arenaria, Elymus mollis, Elytrigia serotina, and Elymus arenarius. These synonyms are used to describe different varieties and subspecies of the same plant. The plant is highly valued for its resilience and resistance to harsh environmental conditions, making it an important species in soil stability and erosion control projects.