Summary of meeting held at IBC Madrid, 27 July 2024

Legume researchers focusing on Caesalpinioideae (including the mimosoids) have recently published two special issues of the journal PhytoKeys: Advances in Legume Systematics 14 parts 1 and 2, and these provide a good model for tackling the Papilionoids:

1. ALS14 part 1: A series of papers, mainly resolving genus non-monophyly highlighted by the studies of Koenen et al. and Ringelberg et al., which cleared up many of the taxonomic and nomenclatural issues in the Caesalpinioideae, with a focus on the mimosoids Hughes C. et al. (2022) Phytokeys 205: 1-470.
2. ALS 14 part 2: A new classification of the Caesalpinioideae, including new or reinstated tribe names, and informal clade names. Bruneau A. et al. (2024) Phytokeys 240: 1-552.

Agreement of those present at the end of the meeting: • Each major research group working on higher level legume systematics should go ahead and publish their phylogenies and the taxonomic and nomenclatural implications of their studies.

• Their published studies could/should suggest clades that could be considered for formal tribal recognition but should not formalise tribal names; those to be agreed by collaborative international legume decision. An important aim would be to avoid nomenclatural instability.

• The final, formal reclassification will be proposed in a legume community publication.

• Although a new tribal classification preferably would be published under the Legume Phylogeny Working Group ‘umbrella’, details of authorship will be discussed and agreed in advance, taking into account different groups’ and individuals’ requirements where possible.

Next stages:

Note – we can arrange online meetings to update others as required.

The legume portal in GBIF (and associated databases) can adopt an agreed tribal classification based on Legumes of the World (2005) with some updates in the interim (as these portals will soon be able to include subfamily and tribe ranks).

Through this process several publications will likely be required to clarify and clean-up phylogenetic and taxonomic problems (e.g., genus level paraphyly and polyphyly). These could be published as one or more special issues of an international journal, prior to the publication of a formal Papilionoideae tribal classification, following the model of ALS 14 parts 1 and 2 for the Caesalpinioideae.

All involved in submitting these phylogenetic/phylogenomic manuscripts for publication will be encouraged to act as reviewers for the manuscripts submitted by other legume research groups, and to be coauthors on the final formal classification paper.

Stage 1:

Establish a Legume Tribes Phylogeny Working Group to compare existing phylogenies. This group will largely consist of the molecular specialists who have produced the phylogenetic trees but taxonomic specialists will also be needed. Below is a proposal for members to be included in the initial working group:

Interested groups and individuals (mostly those working with the phylogenies) to propose members of the group. In the meeting, the following people volunteered:

• Rong Zhang & Tingshuan Yi
• Ryan Folk & Carolina Siniscalchi
• Rafaela Trad
• Ashley Egan

Current phylogenies or ones appearing soon that should be considered include:

• Genomic and enriched (Zhang et al.)
• NITFIX (Folk et al.)
• Angiosperm 353 (Trad et al.)
• Egan et al.
• Bob Jansen and Marty Wojciechowski

Who else is out there?

If you are interested in joining the Legume Tribes Phylogeny Working Group, please contact Greg Kenicer and Rafaela Trad. Note, the phylogeny group is encouraged to consult outside expertise as they go through the following processes:

• Identify and agree on clades that are appropriate (have the support) to be given formal tribal names. This will be based largely on consistently resolving clades that have strong support across all the trees, thus underpinning final nomenclatural decisions and formal naming.

• Identify taxa/clades requiring more sampling, verification of identifications and other issues that may arise

• Deal with disagreements between topologies, and resolve how to name taxon grades in the phylogenies

• Consider diagnosability (morphology, chemistry, ecology, geography) and other issues across the proposed tribes. This will require consultation outside the core group with both phylogenetic and taxonomic experts

• Establish a community consensus final LPWG ratified tribal classification and propose this in a publication to allow the wider user community to respond and comment before the classification is formalised

• A note of caution was raised to take care when suggesting clade names that can easily be latinised by groups working outside the legumes without the expertise, who may publish names opportunistically

Stage 2:

• Based on the Legume Tribes Phylogeny Working Group’s proposed tribal reclassification, together with feedback from the wider legume taxonomic community and other interested parties present a new tribal framework that emphasises stability, broad utility beyond plant systematics, and aims to be conservative where possible

• This will require a separate working subgroup of specialist taxonomists (the Legume Tribes Taxonomic Working Group) to coordinate and ratify the proposal. If you are interested in being involved, please email as above

• Formally publish the new consensus legume tribes classification (this focusing on the Papilionoideae) endorsed by the international legume research and user communities