Towards a new classification of Leguminosae: Naming clades using non-Linnaean phylogenetic nomenclature

•A format for the formal description and naming of clades in legume phylogeny is proposed.•Clade names follow recommended rules of phylogenetic nomenclature as set forth in the draft “PhyloCode”.•Formal clade names can be integrated into rank-based Linnaean and rank-free classification systems.•An example of a rank-free phylogenetic classification of papilionoid legumes is presented.

The past three decades of research have greatly advanced our understanding of phylogenetic relationships in the family Leguminosae. It has become clear in recent years that our classification system is in need of significant updating if it is to reflect our current understanding of the phylogeny of the family and facilitate effective communication of that knowledge. The goal of this paper is to suggest a set of guidelines for formally defining and naming clades, which draws on many of the recommendations embodied in the draft International Code of Phylogenetic Nomenclature or “PhyloCode”. I provide specific examples of phylogenetic nomenclature applied to several well recognized and well-supported, informally named papilionoid clades to serve as a model for standardizing legume clade names by the legume community in the future. For the most part the clades named here are below subfamily and above tribal ranks in the Linnaean system. It is my contention that a new Linnaean classification, designed to reflect phylogeny, and a clade-based system of phylogenetic nomenclature are mutually complementary approaches to achieving a new classification of the legume family.