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Where "identifier" is a user specified name for the network and "rich newick string" is a user specified rich newick string. For more information about rich newick strings see its corresponding reference page.
In addition to the NETWORKS block, the TREES block may also be used to define rich newick strings. However, rich newick strings defined in a TREES block may not contain hybridization nodes. The inclusion of the TREES block in addition to the NETWORKS block is for increased comparability with NEXUS processing tools besides PhyloNet that also consume or produce TREES blocks within NEXUS files.
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