Taxonomy Versus Cladonomy in the Dicot Families1

Abstract

Abstract The theoretical basis for cladistic classification into monophyletic (holophyletic) ranked taxa is fatally flawed and is promoting bad taxonomy. Biological classification that takes account of evolutionary history may be based on two main factors—lines of descent and extent of divergence represented by morphological and other characters. In taxonomy a balance must be found between lines of descent and characters, and insistence on one at the expense of the other will give unacceptable results. Much confusion has arisen in systematics from the failure to appreciate that taxonomy, which groups organisms into ranked taxa (families, genera, etc.), is essentially different from grouping them into clades. These two processes are based on conflicting hierarchies and have different methodologies and functions. For several decades, however, the cladistics movement has adopted lines of descent rather than characters as the sole basis of taxonomy, insisting that only complete clades should be recognized as ...