ner·va·tion /ˌnɝˈveʃən/
  脈狀,葉脈,翅脈
  Ner·va·tion n. The arrangement of nerves and veins, especially those of leaves; neuration.
     The outlines of the fronds of ferns, and their nervation, are frail characters if employed alone for the determination of existing genera.   --J. D. Hooker.
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