From MarineBiotech Infopages
Definition of Marram:
There are two principle species of marram grass Ammophilla arenaria (marram, European marram grass or European beach grass) and A. breviligulata Fern. (American beach grass).
Both species occur in sand dunes, often dominating the early stages of development. They are especially adapted to burial by sand and are drought resistant.
Marram (A. arenaria) is native to the coast of Europe and North Africa, from Scandinavia south to the Mediterranean Sea, and from Ireland east to Egypt.American beach grass (A. breviligulata) occurs on the coasts of eastern North America, including the shores of the Great Lakes.
This is the common definition for Marram, other definitions can be discussed in the article