WHAT IS THE WRITER OF A FLORA TO DO? EVOLUTIONARY TAXONOMY OR PHYLOGENETIC SYSTEMATICS?

Plant classification and nomenclature are in a continuing state of flux and heated debate between two opposing schools— 1) traditional taxonomists supporting "evolutionary" or "Linnaean taxonomy"; and 2) cladists supporting "phylogenetic systematics" or "cladonomy." While it is a multifaceted controversy that has spanned several decades, relatively little attention has been focused specifically on the ramifications for floristics. The two goals of this paper are 1) to give special emphasis to the implications of the controversy for the writers of floras, and 2) to provide an overview of some of the arguments in a format accessible to a diverse audience of botanists interested in floristics. We examine some of the issues we have confronted in our floristic work, discuss how we are attempting to balance the strengths and weaknesses of both approaches, and indicate what we believe is the best, albeit imperfect, approach to the writing of floras at the present time. We argue that, for both practical and theoretical reasons, a modified traditional system (binomial nomenclature, ranked hierarchies) be used in floras (allowing paraphyletic groups but eliminating all polyphyletic groups despite some nomenclatural instability). Further, these floras should incorporate information on newly discovered phylogenetic relationships (even if too preliminary, tentative, or inappropriate for nomenclatural change) and discuss these in appropriate family and generic treatments in order to facilitate as complete an understanding of plant evolution as possible. La clasificación y nomenclatura de las plantas está en un flujo continuo y debate ardiente entre dos escuelas opuestas— 1) taxónomos tradicionales que apoyan la "taxonomía Linneana" o la "evolutiva"; y 2) dadistas que apoyan la "sistemática filogenética" o "cladonomía." Mientras esta controversia se ha extendido durante varias décadas, se ha prestado relativamente poca atención a las ramificaciones de la florística. Las dos metas de este artículo son 1) dar un énfasis especial a las implicaciones de la controversia para los autores de floras, y 2) ofrecer una visión general de algunos de los argumentos en un formato accesible a una audiencia diversa de botánicos interesados en la f lorística. Examinamos algunos de los resultados que hemos confrontado en nuestro trabajo f lorístico, discutimos como hemos intentado equilibrar las bondades y debilidades de ambos métodos, e indicamos lo que creemos que es el mejor, aunque im