The nature of plant species.

The species concept is a central tenet of biological diversity. Attempts to describe diversity have led to empirical concepts of species based on assumptions found wanting for plants. Plant species lack reality, cohesion, independence, and simple evolutionary or ecological roles. The concept of species for plant taxonomists and evolutionists can only serve as a tool for characterizing diversity in a mentally satisfying way. Diversity is idiosyncratic. ft is impossible to reconcile idiosyncrasy with preconceived ideas of diversity. The search for hidden likenesses is unlikely to yield a unifying species concept. The concept that is most operational and utilitarian for plants is a mental abstraction which orders clusters of diversity in multidimensional character space.