A tree consists of two types of 'nodes':
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tips or terminal nodes: species
connected to exactly one father
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inner nodes: hypothetical ancestors
connected to one father (and in the binary case to two children). A group_name may be assigned to an inner node; in this case, the node and all its children become a group. <ARB_NT/INFO_MODE/M>
There are significant differences between phylogenetic trees and binary trees:
phylogenetic trees binary trees:
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unrooted rooted
inner nodes have n children all inner nodes have two children Since binary trees are much easier to handle, ARB converts phylogenetic trees to binary trees.
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