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''Alisma'' is a genus of flowering plants in the family Alismataceae, members of which are commonly known as water-plantains. The genus consists of aquatic plants with leaves either floating or submerged, found in a variety of still water habitats around the world (nearly worldwide).〔(【引用サイトリンク】 work = Flora of North America )〕〔(Kew World Checklist of Selected Plant Families )〕 The flowers are hermaphrodite, and are arranged in panicles, racemes, or umbels. ''Alisma'' flowers have six stamens, numerous free carpels in a single whorl, each with 1 ovule, and subventral styles. The fruit is an achene with a short beak. The nineteenth century British art and social critic John Ruskin believed that the particular curve of the leaf-ribs of ''Alisma'' represented a model of 'divine proportion' and helped shape his theory of Gothic architecture.〔J. Mordaunt Crook, "Ruskinian Gothic" in The Ruskin Polygon: Essays on the Imagination of John Ruskin ed. John Dixon Hunt and Faith M. Holland (Manchester University Press, 1982) pp. 65–93.〕 ''Copóg Phádraig'' ("''leaf of Patrick''") is the Irish name for the water-plantain. It is reputed to ward off fairies. Water plantains are perennial plants. These herbs are usually emergent plants 0.1 – 1 m high. They have broad leaves that can be either tapered or rounded at the base. When submerged, the plant produces ribbon-like leaves. Inflorescences are highly branched. They produce whorls of perfect flowers either white or pinkish. The fruits are flat-sided nutlets 2.5 – 3 mm in length. These herbs usually flower in late May to early September, but thiscan vary with conditions.〔Gleason and Cronquist (1991); Fernald (1970); Voss (1972).〕 Water-plantains are wetland plants and found in saturated soils and shallow water as well as marshes, wooded swamps, shrub swamps and flooded farmland. When introduced to an area, water plantain can rapidly reproduce. ==Species and subspecies== The following taxa are recognized as of May 2014:〔 *''Alisma × bjoerkqvistii'' Tzvelev - Russia * ''Alisma canaliculatum'' A.Braun & C.D.Bouché - eastern Asia * ''Alisma gramineum'' Lej. - Europe, Asia, North Africa; minor naturalization in North America *''Alisma × juzepczukii'' Tzvelev - Russia * ''Alisma lanceolatum'' Withering - Europe, Asia, North Africa; naturalized in Australia, New Zealand, California etc. * ''Alisma nanum'' D.F.Cui - Xinjiang * ''Alisma orientale'' * ''Alisma plantago-aquatica'' L. - Europe, Asia, Africa * *''Alisma plantago-aquatica'' subsp. ''orientale'' (Sam.) Sam. * *''Alisma plantago-aquatica'' subsp. ''plantago-aquatica'' *''Alisma × rhicnocarpum'' Schotsman - western Europe * ''Alisma subcordatum'' Raf. eastern North America * ''Alisma triviale'' Pursh - North America * ''Alisma wahlenbergii'' (Holmb.) Juz. Baltic Sea region 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「Alisma」の詳細全文を読む スポンサード リンク
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