A COMPARISON OF PHYLOGENETIC NOMENCLATURE WITH THE CURRENT SYSTEM - ABOTANICAL CASE-STUDY

The family Lamiaceae was used as a case study to compare our current s ystem of nomenclature with a phylogenetic alternative proposed by de Q ueiroz and Gauthier (1992, Annu. Rev. Ecol. Syst. 23:449-480), with em phasis on nomenclatural stability and efficiency. Comparison of publis hed cladistic analyses revealed 19 suprageneric clades within Lamiacea e that are supported well enough to merit naming, but many genera coul d not be placed with confidence in any infrafamilial taxon. Two phylog enetic classifications were prepared, one following current nomenclatu ral rules and conventions and the other following the phylogenetic sys tem of nomenclature. A comparison of the classifications revealed exam ples of unstable and ambiguous names that resulted from employing curr ent rules and conventions to name clades. Old names based on nomenclat ural types of uncertain phylogenetic relationship and infrafamilial ta xon names based on the type of the family are particularly prone to in stability. The phylogenetic system appears to have fewer problems but may also lead to nomenclatural confusion if taxon names are defined ca relessly. The current system produces less efficient classifications b ecause the principle of exhaustive subsidiary taxa leads to inclusion of redundant names (monotypic taxa) when the classification is based o n an asymmetrical cladogram. In contrast, the phylogenetic system cont ains no redundant names. We endorse the recommendation that the princi ple of exhaustive subsidiary taxa be abandoned. Phylogenetic definitio ns should be provided for taxon names whenever phylogenies are transla ted into classifications. The definitions should be accompanied by a l ist of synapomorphies and a statement of clade membership to facilitat e subsequent provisional referral of newly studied species to supraspe cific taxa.