Testing generic limits in Cercidoideae (Leguminosae): Insights from plastid and duplicated nuclear gene sequences

Reconstructing the phylogenetic history of species in large taxonomic groups remains a challenge despite ever increasing access to molecular data. In subfamily Cercidoideae (Leguminosae), the large pantropical Bauhinia s.l. (~380 spp.) is never supported as monophyletic, but the generic boundaries and the number of genera that should be recognised remains a challenging taxonomic and phylogenetic question. Here we reconstruct the phylogeny of Bauhinia s.l. and related genera in the subfamily using sequences obtained from five loci ( matK , trnL‐F , Leafy , and two previously undetected duplicate copies of Legcyc ), which we analyse individually and in a concatenated matrix (excluding Leafy ). The individual and concatenated analyses generally support two distinct lineages in Bauhinia s.l.: (1) the Bauhinia clade, containing Bauhinia s.str., Brenierea , and Piliostigma ; and (2) the Phanera clade, containing Barklya , Cheniella , Gigasiphon , Lasiobema , Lysiphyllum , Phanera s.str., Schnella , and Tylosema . Based on our analyses, we recognise 14 genera in Cercidoideae. We resurrect the genus Tournaya from Gigasiphon , and synonymise the Asian segregate genus Lasiobema back into Phanera s.str. Our analyses reveal a clear gene duplication event in CYCLOIDEA that is shared by all Cercidoideae excluding the sister lineage to the subfamily, Cercis , supporting recent hypotheses for a whole genome duplication in all Cercidoideae except this genus.