The grass
The genus name Ammophila comes from the Greek words ámmos, meaning "sand", and philos, meaning "friend". The grasses are found almost exclusively on the first line of coastal dunes. Their extensive system of creeping underground stems, or rhizomes, lets them thrive in shifting sands and high winds and helps stabilize the dunes and prevent coastal erosion. Ammophila species are native to the coasts of the North Atlantic Ocean, where they are usually the dominant species on dunes. The grasses are not particularly tolerant of saline soils, although they can tolerate a salinity of about 15 g/L (1.5%).
Species
Only two species seem incontrovertible: Ammophila arenaria and Ammophila breviligulata. Ammophila arenaria, European marram grass or European beachgrass, is native to the coasts of Europe, north to Iceland, and to northwest Africa. It is a perennial grass forming stiff, hardy clumps of erect stems up to 1.2 metres in height. Ammophila breviligulata, American marram grass or American beachgrass, is native to the coasts of eastern North America, including the shores of the Great Lakes. The leaves of Ammophila breviligulata have deeply furrowed upper surfaces and smooth undersides and grow 1 to 3 feet (0.3 to 0.9 m) tall. A taxonomic database treats Ammophila breviligulata as a synonym of Calamagrostis breviligulata. The name breviligulata comes from the Latin brevis, "short", and ligula, "tongue", and refers to the ligule, a feature of grass leaves. Compared with A. arenaria, A. breviligulata has smaller ligules, wider and less inrolled leaves, and a longer flower spike. Champlain beachgrass, native to the shores of Lake Ontario and Lake Champlain, is very similar to A. breviligulata and is no longer considered a distinct species by several authorities. A hybrid between A. arenaria and Calamagrostis epigejos, called purple marram, occurs in parts of northern Europe.
Ecology
In Europe, Ammophila arenaria is the dominant species on dunes, stabilizing and building the foredune by capturing blown sand and binding it with its tough, fibrous rhizome system. The beachgrass species can tolerate burial in as much as 3 feet (0.9 m) of sand, and sand burial stimulates the rhizomes to grow vertically. Marram grass has a rolled leaf that creates a localized environment of water vapour concentration within the leaf and helps to prevent water loss.
Adaptations and habitat
The leaves of Ammophila arenaria are up to 0.9 metres long and 6 mm wide, with inrolled margins and a sharply pointed apex. In marram grass the stomata sit in small pits within the curls of the rolled leaf, and a waxy cuticle on the leaf surface also inhibits evaporation. Marram grass prefers the active sand area and the windward side of the foredune. Ammophila arenaria has also been introduced and naturalised in Australia, southern South America, the Falkland Islands, New Zealand, South Africa, and the east and west coasts of Canada and the United States.
Uses of the plant
The ability of marram grass to grow on and bind sand makes it a useful plant in the stabilization of coastal dunes and artificial defences on sandy coasts. The flowering stems and leaves are used for thatching, basketry and making brooms. Fibre from the stem is used for making paper, and the rhizomes are used for making rope and mats. The roots of marram grass are edible, although thin and fibrous.
Invasiveness
Ammophila is now invasive in virtually all of the locations where it has been introduced. Ammophila arenaria is one of the most problematic noxious weeds of coastal California, where it is called European beachgrass. It forms dense monotypic stands that crowd out native vegetation and cover open stretches of sand used for nesting by the threatened western snowy plover. An effort to remove Ammophila arenaria from Morro Strand State Beach began in 2000 and combined herbicide treatments with handpulling. The initial treatment achieved a 60 percent mortality after several months.
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Related: Deer Tongue Grass · Gingergrass · Grass · Hay · Nut Grass · Sabah Snake Grass · Sweet Grass
