Marram Grass (Ammophila arenaria)
The seaside is a complex place naturally speaking. Where salt water meets the land a unique environment is created, a harsh environment with ever changing conditions, especially with the influences of the tide.
Where sandy shores result sand dunes often follow. Not a lot can grow in sand but this plant, Marram Grass can In fact, so good at growing in sand and binding sand together from stopping it spreading it is actually planted for this purpose in some areas.
Marram Grass grows just about anywhere there is sand and so the sandy dunes behind Studland Beach are one obvious place to look for it.