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''Acrostichum'' is a fern genus in the Ceratopteridoideae subfamily of the Pteridaceae.〔 It was one of the original pteridophyte genera delineated by Linnaeus. It was originally drawn very broadly, including all ferns that had sori apparently "acrostichoid", or distributed in a solid mass across the back of the frond, rather than organized in discrete sori. This led Linnaeus to include such species as ''Asplenium platyneuron'' in the genus, because the specimen he received had sori so crowded that it appeared acrostichoid. Since ''Acrostichum aureum'' is regarded as the type for the genus, it is now narrowly circumscribed only to the natural genus of three species, that are allied to the genus ''Ceratopteris''. They are collectively known as the leather ferns or leather swamp ferns, genus members commonly being found in swamps. The species of ''Acrostichum'' are massive ferns, with fronds up to 12 feet (3.5 meters) tall, that depend on a semi-aquatic existence. They do not withstand prolonged immersion, but require wet roots. The species ''Acrostichum aureum'' is known to have a high saltwater tolerance, growing in mangroves. ==Species== *''Acrostichum aureum'' L. *''Acrostichum danaeifolium'' (Langsd.) Fisch. *''Acrostichum speciosum'' Willd. *''Acrostichum preaureum'' fossil plant. 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「Acrostichum」の詳細全文を読む スポンサード リンク
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