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.

The Tribe Wisterieae (Zhu 1994), founded on the single genus Wisteria, is emended and recircumscribed based on morphology and data from nuclear ITS and ndhJ-trnF, matK and rbcL chloroplast DNA sequences. This newly enlarged tribe comprises 36 species and 9 infraspecific taxa within 13 described genera. Six genera are new, two are reinstated and five were previously placed in Tribe Millettieae. The genus Adinobotrys is also reinstated comprising two species including the new combination A.vastus. Other reinstated genera include Whitfordiodendron, with four species, and Padbruggea, with three species, including the reinstatement of P.filipes and the new combination P.filipesvar.tomentosa. The existing genera Afgekia, Callerya, Endosamara (with the new combination E.racemosavar.pallida), Sarcodum and Wisteria, with the new combinations W.frutescenssubsp.macrostachya are evaluated. The new genera comprise three Australasian species in Austrocallerya: A.australis, A.megasperma and A.pilipes; Wisteriopsis with five species from east Asia has six new combinations: W.japonica, W.kiangsiensis, W.championii, W.eurybotrya, W.reticulata and W.reticulatavar.stenophylla. Two species comprise the new Thai genus Kanburia: K.tenasserimensis and K.chlorantha. Nanhaia comprises the two species: N.fordii and N.speciosa and the monotypic genera Sigmoidala and Serawaia are based respectively on the species S.kityana and S.strobilifera. Lectotypes are designated for the names Adinobotrysfilipes, A.myrianthus, Millettiabonatiana, Millettiabracteosa, Millettiachampionii, Millettiacinerea, Millettiadielsiana, Millettiakityana, M.maingayi, Millettianitida, Millettiaoocarpa, Millettiapurpurea, M.reticulata, M.reticulatavar.stenophylla, Padbruggeadasyphylla, Pterocarpusaustralis, Robiniaracemosa, Whitfordiodendronscandens, W.sumatranum and Wisteriapallida. A neotype is designated for the name Millettialeiogyna.

Callerya chlorantha and C. tenasserimensis, here illustrated and described as new to science, are found in dry deciduous or bamboo forest in Kanchanaburi and Ratchaburi provinces in Thailand. Callerya chlorantha, characterized by having pale green flowers that are rare in the genus, grows on limestone. This species is considered as Data Deficient (DD) at this time because there are not yet sufficient data about its distribution, abundance or threats. Callerya tenasserimensis has glabrous leaves and stems and rather small, purple or maroon flowers with golden-brown hairs on the calyx and abaxial side of the standard petal. The conservation status of this species is assessed as Vulnerable (VU).

Following recent mimosoid phylogenetic and phylogenomic studies demonstrating the non-monophyly of the genus Albizia, we present a new molecular phylogeny focused on the neotropical species in the genus, with much denser taxon sampling than previous studies. Our aims were to test the monophyly of the neotropical section Arthrosamanea, resolve species relationships, and gain insights into the evolution of fruit morphology. We perform a Bayesian phylogenetic analysis of sequences of nuclear internal and external transcribed spacer regions and trace the evolution of fruit dehiscence and lomentiform pods. Our results find further support for the non-monophyly of the genus Albizia, and confirm the previously proposed segregation of Hesperalbizia, Hydrochorea, Balizia and Pseudosamanea. All species that were sampled from section Arthrosamanea form a clade that is sister to a clade composed of Jupunba, Punjuba, Balizia and Hydrochorea. We find that lomentiform fruits are independently derived from indehiscent septate fruits in both Hydrochorea and section Arthrosamanea. Our results show that morphological adaptations to hydrochory, associated with shifts into seasonally flooded habitats, have occurred several times independently in different geographic areas and different lineages within the ingoid clade. This suggests that environmental conditions have likely played a key role in the evolution of fruit types in Albizia and related genera. We resurrect the name Pseudalbizzia to accommodate the species of section Arthrosamanea, except for two species that were not sampled here but have been shown in other studies to be more closely related to other ingoid genera and we restrict the name Albizia s.s. to the species from Africa, Madagascar, Asia, Australia, and the Pacific. Twenty-one new nomenclatural combinations in Pseudalbizzia are proposed, including 16 species and 5 infraspecific varietal names. In addition to the type species Pseudalbizzia berteroana, the genus has 17 species distributed across tropical regions of the Americas, including the Caribbean. Finally, a new infrageneric classification into five sections is proposed and a distribution map of the species of Pseudalbizzia is presented.

Sophora huamotensis Mattapha, Suddee & Rueangr. is illustrated and described here. This new species is recognised by having numerous leaflets, articulated pedicels and the wing petals with lunate sculpturing on the outer surface and without auricles at the base. The morphological characters of the species are compared and discussed with its closest species. Description, illustration, images and a distribution map of the new species are provided.