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Ammophila (synonymous with Psamma P. Beauv.)is a genus consisting of two or three very similar species of grasses; common names for these grasses include Marram Grass, Bent Grass, and Beachgrass. These grasses are found almost exclusively on the first line of coastal sand dunes; their extensive systems of creeping underground stems or rhizomes allow them to thrive under conditions of shifting sands and high winds. Ammophila species are native to the coasts of the North Atlantic Oceanmarker where they are usually the dominant species on sand dunes. Their native range includes few inland regions, with the Great Lakesmarker of North America being the main exception. The genus name "Ammophila (Am-mó-phi-la) " originates from the Greek words of Ammos, meaning sand, and Phillia, meaning lover.

The Ammophila grasses are widely known as examples of xerophytes, which are plants that can withstand arid conditions such as deserts or sandy beaches. Its xerophytic adaptations (mentioned below) allow it to thrive under conditions most plants could not survive. Despite their occurrence on seacoasts, Ammophila grasses are not particularly tolerant of saline soils; they can tolerate a salinity of about 15 g/l (1.5%), which makes them "moderate halophytes".

Ammophila builds coastal sand dunes and thus stabilizes the sand. For this reason, the plants have been introduced far from their native range. Alfred Wiedemann writes that, starting in the early 1800s, Ammophila arenaria "has been introduced into virtually every British colonial settlement within its latitudinal tolerance range, including southeast and southwest Australia, New Zealand, South Africa, the Falkland Islands, and Norfolk Island. It has been planted widely in Japan and has been reported from Argentina and Chile." Ammophila species were introduced in the late 1800s on the Pacific coast of North America as well, and massive, intentional plantings were continued at least through 1960. In essentially all of the locations where they have been introduced, Ammophila plants are now listed as invasive, and costly efforts are underway to eradicate them.

Species

Only two species seem incontrovertible: A. arenaria and A. breviligulata. Two other species have been proposed, and are discussed below.
  • A. arenaria - European Marram Grass or European Beachgrass. Native to coasts of Europe (north to Icelandmarker) and northwest Africa. Inflorescence to 25 cm long; broad.
  • A. baltica has now been identified as a natural hybrid, × Ammocalamagrostis baltica, between Ammophila arenaria and Calamagrostis epigeios. The hybrid occurs in parts of northern Europe, mainly from the Baltic Seamarker west to eastern Englandmarker.
  • A. breviligulata - American Marram Grass or American Beachgrass. Native to coasts of eastern North America, including the shores of the Great Lakesmarker. Inflorescence to 30 cm long; narrower than A. arenaria.
  • A. champlainensis or A. breviligulata ssp. champlainensis - Champlain Beachgrass. Native to shores of Lake Ontariomarker and Lake Champlainmarker. Inflorescence to 22 cm long; very similar to A. breviligulata, and no longer considered a distinct species by several authorities.


Ecology

In Europe, Ammophila arenaria has a coastal distribution, and is the dominant species on sand dunes where it is responsible for stabilising and building the foredune by capturing blown sand and binding it together with the warp and weft of its tough, fibrous rhizome system. Marram grass is strongly associated with two coastal plant community types in the British National Vegetation Classification. In community SD6 (Mobile dune) Ammophila is the dominant species. In the semi-fixed dunes (community SD7), where the quantity of blown sand is declining Ammophila becomes less competitive, and other species, notably Festuca rubra (Red Fescue) become prominent.

Uses

Newboroughmarker women once used marram grass in the manufacture of mats, haystack covers and brushes for whitewashing.

The ability of marram grass to grow on and bind sand makes it a useful plant in the restoration of coastal defences on sandy coasts.

Marram grass has been widely used for thatch in many areas of the British islesmarker close to the sea. The harvesting of marram grass for thatch was so widespread during the 17th century that it had the effect of destabilizing dunes, resulting in the burial of many villages, estates and farms. In 1695 the practice was banned by an Act of the Scottish Parliament:

References

  1. The identification of Champlain beachgrass as a species that is distinct from A. breviligulata is still under investigation, and some authors consider Champlain beachgrass to be a subspecies A. breviligulata ssp. champlainensis (Seymour) P.J. Walker, C.A. Paris & Barrington ex Barkworth. Recent work on morphological differences between varying populations assigned to A. breviligulata and to A. champlainensis do not support the assignment of a distinct species for the latter specimens, despite significant differences. See


Gallery

Image:Illustration Ammophila arenaria0.jpg|European Marram Grass (left) with Velvet Bent (right).Image:Studland Beach-Flooded Shell Bay.JPG|Beds of Marram grass (foreground) in November in the dunes on Studlandmarker, Dorsetmarker, UKmarkerImage:Ostduinkerke-d.JPG|European Marram Grass at Oostduinkerke, Belgium.Image:AmericanMarramGrassKohlerAndraeStateParkLakeMichigan.jpg|American beachgrass on Lake Michiganmarker in November.

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