Leymus arenarius; Lyme-grass generally is a coastal plant growing on sandy dunes and higher regions of beaches. On Iceland though, this species can also be found on the "sandy" volcanic ash-soils of the highlands and "sandur" plains of the south coast. Both this species and the closely related foreign species Leymus mollis (American Lyme-grass) have been widely introduced for the purpose of combating soil erosion in the wind-erosion prone highland regions.
The American Lyme-grass can be distinguished from the (European-) Lyme-grass by the hairy top of the culm below the spike. This species is much rarer and easily overlooked.
Both are members of the grass family (Poaceae, also known as Gramineae). The Icelandic name of Lyme-grass is Melgresi.