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''Geum rivale'', the water avens, is a flowering plant of the family Rosaceae. Other names for the plant are nodding avens, drooping avens, cure-all, water flower and indian chocolate.〔(A Modern Herbal. )〕 It is native to much of Europe, with the exception of Mediterranean areas, as well as some parts of Central Asia and North America.〔(【引用サイトリンク】title=Den virtuela floran: ''Geum rivale'' )〕 In North America, it is known as purple avens.〔(【引用サイトリンク】title=Plants Profile for ''Geum rivale'' L. (purple avens) )〕 It grows in bogs and damp meadows,〔(【引用サイトリンク】title=Water Avens (Purple Avens) ''Geum rivale'' )〕 and produces nodding red flowers from May to September. The plant is a native perennial of slow-draining or wet soils and can tolerate mildly acidic to calcareous conditions in full sun or under partial shade. Habitats include stream sides, pond edges, damp deciduous woodland and hay meadows.〔(Wildseeds Website. )〕 ''G. rivale'' is pollinated primarily by bees, less often by flies and beetles. As the flower matures, elongation of the stamens ensures it self-fertilises if not already cross-pollinated. The flowers stigmas mature before the stamens. It begins flowering a little earlier than ''G. urbanum'', so early pollinations will be within the gene-pool of the single species.〔(Biodiversity site. )〕 The seeds of Water Avens are burr-like, and are distributed after being caught in the coats of rabbits and other small mammals,〔(First Nature wildflowers. )〕 and by rhizomal growth〔 ''G. rivale'' is parasitised by ''Podosphaera aphanis'' – a conidial powdery mildew.〔Ing, B.( 1990). An Introduction to British Powdery Mildews.〕 Yellow spots on the living leaf may be caused by ''Peronospora gei'' – a downy mildew.〔Ellis, M. B. & J. P. (1997). Microfungi on Land Plants: An Identification Handbook.〕 ''Geum urbanum'' hybridises fairly regularly with ''Geum rivale'' as they are closely related and occur together. It is a component of Purple moor grass and rush pastures is a type of Biodiversity Action Plan habitat in the UK. It occurs on poorly drained neutral and acidic soils of the lowlands and upland fringe. It is found in the South West of England, especially in Devon. File:Geum rivale clump.jpg|Group of plants File:Geum rivale flowers.jpg|Flowers File:Geum rivale with pseudopeloria.jpg|Pseudo-peloric flower File:Geum rivale fruit.jpg|Fruits ==References== 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「Geum rivale」の詳細全文を読む スポンサード リンク
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