XVI International Botanical Congess

The task of converting phylogenetic hypotheses into classifications is especially difficult in groups where phylogenetic relationships are poorly known. At the same time, the need for efficient, flexible classification systems is especially acute in poorly known groups. Phylogenetic uncertainty takes several forms, for example, it can involve uncertainty about relationships among described taxa, or uncertainty about the species richness of recognized groups. The inherent stability of rank-free classification systems makes them superior to ranked systems for dealing with rearrangements among clades, or addition or deletion of clades. A special kind of phylogenetic uncertainty involves questions about the numbers of cryptic species that are concealed within currently recognized species. Rank-free classification systems that maintain a nomenclatural distinction between clades and species perform much like the current ranked system when dealing with the discovery that a previously recognized species actually contains multiple lineages. In this talk, we will discuss possible mechanisms for dealing with various forms of phylogenetic uncertainty in phylogenetic taxonomy.