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Phylloclades and cladodes are flattened, photosynthetic shoots, which are usually considered to be modified branches. The two terms are used either differently or interchangeably by different authors. ''Phyllocladus'', a genus of conifer, is named after these structures. Phylloclades/cladodes have been identified in fossils dating from as early as the Permian. ==Definition and morphology== The term "phylloclade" is from the New Latin ''phyllocladium'', itself derived from Greek ''phyllo'', leaf, and ''klados'', branch. Definitions of the terms "phylloclade" and "cladode" vary. All agree that they are flattened structures that are photosynthetic and resemble leaf-like branches. In one definition, phylloclades are a subset of cladodes, namely those that greatly resemble or perform the function of leaves,〔 p. 448〕 as in Butcher's broom (''Ruscus aculeatus'') as well as ''Phyllanthus'' and some ''Asparagus'' species. By an alternative definition, cladodes are distinguished by their limited growth and that they involve only one or two internodes. By this definition, some of the most leaf-like structures are cladodes, rather than phylloclades. By that definition, ''Phyllanthus'' has phylloclades, but ''Ruscus'' and ''Asparagus'' have cladodes. Another definition uses "phylloclade" to refer a portion of a leaf-like stem or branch with multiple nodes and internodes, and "cladode" for a single internode of a phylloclade.〔 p. 87.〕 Although phylloclades are usually interpreted as modified branches, developmental studies have shown that they are intermediate between leaves and branches as their name indicates. Molecular genetic investigations have confirmed these findings. For example, Hirayama et al. (2007) showed that the phylloclade of ''Ruscus aculeata'' "is not homologous to either the shoot or the leaf, but that it has a double organ identity," which means that it combines shoot and leaf processes. Phylloclades also occur in ''Bryophyllum'' and ''Kalanchoe''. 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「Phylloclade」の詳細全文を読む スポンサード リンク
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