An end to all things? — plants and their names

Abstract

Great advances in our understanding of phylogenetic relationships have been made over the last decade and a half. Major clades in many groups, including flowering plants, now show substantial stability both in terms of content and relationships. This makes possible the development of a system in which only monophyletic ( = holophyletic) entities are named, entities that represent all and only the descendants of a common ancestor. However, some argue that use of Linnaean ranked names is inappropriate in such circumstances; this argument is bolstered by appeals to history and philosophy. Those who doubt the wisdom and / or very possibility of naming only monophyletic groups also argue that their position follows from history, or that ancestors cannot be incorporated into a Linnaean-type classification and that ancestors are an integral part of monophyletic groups. However, I argue that most of the apparently more cosmic issues brought up in this debate are based on a combination of a misunderstanding of the nature and purpose of language, fallacious reasoning and dubious—and largely irrelevant—interpretations of history. A flagged hierarchy helps memory and communication. Binomials in particular simply represent the noun–adjective combinations of ordinary language in a Latinised form, and are too valuable a communication device to be discarded because rank has been demonised. However, hierarchies can be misinterpreted and cannot be made complex enough to cope with the much more detailed phylogenies being produced. Thinking of naming systems as conventions may help clarify what we should be doing, if we are not to squander both the time and the reputation of systematics. Time is in short supply and our reputation not what it might be; solving the less cosmic issues may involve a self-discipline that also seems in short supply in the systematic community.