Adelphotaxon

In the structure of the phylogenetic system, as in every hierarchical ordering, a sequence of ranks between the taxa of the individual levels is necessarily linked with the sequence of hierarchical levels. Here the following law applies: the adelphotaxa of any given level of coordination have identical rank.

When justifying the monophyly of system unities and working out their ground patterns, we usually, more or less immediately, draw upon the subordinated adelphotaxa.