The classification of the legume family proposed here addresses the long‐known non‐monophyly of the traditionally recognised subfamily Caesalpinioideae, by recognising six robustly supported monophyletic subfamilies. This new classification uses as its framework the most comprehensive phylogenetic analyses of legumes to date, based on plastid matK gene sequences, and including near‐complete sampling of genera (698 of the currently recognised 765 genera) and ca. 20% (3696) of known species. The matK gene region has been the most widely sequenced across the legumes, and in most legume lineages, this gene region is sufficiently variable to yield well‐supported clades. This analysis resolves the same major clades as in other phylogenies of whole plastid and nuclear gene sets (with much sparser taxon sampling). Our analysis improves upon previous studies that have used large phylogenies of the Leguminosae for addressing evolutionary questions, because it maximises generic sampling and provides a phylogenetic tree that is based on a fully curated set of sequences that are vouchered and taxonomically validated. The phylogenetic trees obtained and the underlying data are available to browse and download, facilitating subsequent analyses that require evolutionary trees. Here we propose a new community‐endorsed classification of the family that reflects the phylogenetic structure that is consistently resolved and recognises six subfamilies in Leguminosae: a recircumscribed Caesalpinioideae DC., Cercidoideae Legume Phylogeny Working Group (stat. nov.), Detarioideae Burmeist., Dialioideae Legume Phylogeny Working Group (stat. nov.), Duparquetioideae Legume Phylogeny Working Group (stat. nov.), and Papilionoideae DC. The traditionally recognised subfamily Mimosoideae is a distinct clade nested within the recircumscribed Caesalpinioideae and is referred to informally as the mimosoid clade pending a forthcoming formal tribal and/or clade‐based classification of the new Caesalpinioideae. We provide a key for subfamily identification, descriptions with diagnostic charactertistics for the subfamilies, figures illustrating their floral and fruit diversity, and lists of genera by subfamily. This new classification of Leguminosae represents a consensus view of the international legume systematics community; it invokes both compromise and practicality of use.

Dialium (Leguminosae, Dialiinae) is pantropical and comprises about 40 species. Presently, only one species occurs in the Neotropics, Dialium guianense, which is found from eastern Mexico to northeastern Minas Gerais, Brazil. The objective of this study was to carry out a thorough taxonomic revision of Dialium in the Neotropics, to determine if species diversity of the genus in this region is underestimated. The study analyzed 765 collections, from 18 herbaria throughout the world, which revealed three groups of specimens that clearly differ from each other and from D. guianense. Morphology and biogeography support their recognition as new species. Dialium hexaestaminatum occurs in northern Colombia and western Venezuela, and is characterized by generally having six stamens, while the other neotropical species have only two. Dialium congestum occurs in Ecuador and southern Colombia and is mainly characterized by the presence of congested inflorescences, unlike the lax inflorescences found in the other neotropical species.  Dialium rondoniense occurs in the state of Rondônia and the most southern part of the state of Amazonas, Brazil. It is characterized by the dense coverage of trichomes on the abaxial surface of the leaflets, as well as the petiolules, petioles, leaf rachis and branches, while the other neotropical species are generally glabrous or covered with sparse trichomes that are imperceptible to the bare eye. The results show that the diversity of Dialium in the Neotropics was underestimated and that the genus has four species in the region. An identification key, illustrations and descriptions of the species are provided.

In this work, we describe Dialium heterophyllum, a new species for the largest genus in the diverse and morphologically unique legume subfamily Dialioideae. Dialium, with 32 species, has its highest diversity in tropical Africa and Asia, with four species accepted until now in the Neotropics. The fifth species described here reinforces the idea that a large portion of the Neotropical diversity, notably in the Amazon, is still unknown. Dialium heterophyllum is restricted to the south of the Amazon Basin in Brazil and Bolivia, areas under intense anthropic pressure in recent years. Due to its floral morphology, the species appears to be closely related to the other Neotropical species of the genus, differing by its reduced leaf rachis with unifoliolate to trifoliolate leaves, generally opposed to sub-opposed leaflets, the terminal leaflet much longer than the lateral ones (when present) and than the leaf rachis. We provide illustrations, distribution maps, a conservation risk assessment and an identification key.

Martiodendron (Leguminosae/Fabaceae) is a Neotropical genus of trees and shrubs comprising five species. It is characterized by its yellow pentamerous corolla, four to five long poricidal anthers and large, attractive red samaras; it represents an intermediate stage of floral reduction among the 17 genera of the subfamily Dialioideae, which display diverse floral morphologies including different types of reduced flowers in the perianth and androecium. The last taxonomic revision of Martiodendron was published some 60 years ago and there is frequent misidentification of specimens in herbaria, databases, and floristic works with mistreatment of taxa and unclear geographic distributions. Thus, circumscriptions of the species and varieties of the genus require reassessment in light of the substantial new data that has become available during the last several decades. Here, we synthesized morphological, geographical, and ecological data on the genus to produce a modern integrative taxonomic treatment. Our taxonomic concepts are underpinned by analysis of 352 herbarium specimens and substantial fieldwork in South America. We recognize five species and four varieties of Martiodendron. All of these taxa display high levels of morphological and geographical cohesion. One of the varieties, M. mediterraneum var. concinnum, is described as new to science. Detailed descriptions of each recognized taxa are accompanied by illustrations, distribution maps, conservation status assessments, and complete nomenclatural treatments with four new lectotypifications. An identification key and a morphometric analysis of fruits are also provided.

N/A