XVI International Botanical Congess

Linnaean taxonomy and nomenclature, based on mutually exclusive taxa and a pre-determined hierarchy of ranks, are well suited to cataloguing biodiversity. Phylogenetic taxonomy and nomenclature, based on a potentially infinite series ofsuccessively internested clades with no ranks, are a quite different matter. Any attempt to develop a nomenclature for monophyletic taxa (clades) should be completely independent of the Linnaean system and not confusable with it. The present Code provides an efficient set of rules, to which only minor changes are needed. Attempts to eliminate paraphyletic taxa from Linnaean classification cause nomenclatural instability. The main question for Linnaean nomenclature is whether the principles of priority and the type method should be abandoned.