|
''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, and to help stabilize and prevent coastal erosion. ''Ammophila'' species are native to the coasts of the North Atlantic Ocean where they are usually the dominant species on sand dunes. Their native range includes few inland regions, with the Great Lakes of North America being the main exception. The genus name "''Ammophila''" originates from the Greek words of ''Ammos'' (ἄμμος), meaning sand, and ''Phillia'' (ϕιλος), 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".〔(【引用サイトリンク】title=Comprehensive Report Species - Ammophila arenaria )〕 ''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 19th century, ''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 19th century 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 Iceland) and northwest Africa. Inflorescence to 25 cm long; broad. * ''A. baltica'' - Purple Marram. ''A. baltica'' has now been identified as a hybrid between ''A. arenaria'' and ''Calamagrostis epigejos''. The hybrid occurs in parts of northern Europe, mainly from the Baltic Sea west to eastern England, and is known as ''× Ammocalamagrostis baltica'' or ''× Calammophila baltica''.〔(【引用サイトリンク】url=https://data.nbn.org.uk/Taxa/NHMSYS0001754369 )〕 * ''A. breviligulata'' - American Marram Grass or American Beachgrass. Native to coasts of eastern North America, including the shores of the Great Lakes. Inflorescence to 30 cm long; narrower than ''A. arenaria''. * ''A. champlainensis'' or ''A. breviligulata'' ssp. ''champlainensis'' - Champlain Beachgrass. Native to shores of Lake Ontario and Lake Champlain. Inflorescence to 22 cm long; very similar to ''A. breviligulata'', and no longer considered a distinct species by several authorities.〔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 〕〔 (【引用サイトリンク】publisher=New York Natural Heritage Program )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ammophila (plant)」の詳細全文を読む スポンサード リンク
|