A revised delimitation of the species‐rich genus <i>Pilea</i> (Urticaceae) supports the resurrection of <i>Achudemia</i> and a new infrageneric classification

Abstract Ensuring that genera are monophyletic should result in a stable classification better reflects evolutionary history, and which can serve as framework for answering broader scientific questions. It is also important species be assigned to easily unambiguously so remove barriers identification discovery. Pilea , with 933 published names likely more than 700 spp. the largest genus within Urticaceae was last monographed 1869. Whilst monophyly of has been proposed by previous authors, this based on incomplete taxon sampling failed resolve position key taxa. We aimed generate robust phylogeny allied could test provide taxonomic revision species‐rich yet poorly studied genus. To do so, we sought sample taxa encompassing infrageneric classifications anomalous inflorescences or flower morphology use resulting evaluate delimitation establish an classification. In addition, included representative Polynesian Haroldiella which, morphologically, seemed indistinguishable from . Using two plastid one nuclear region, constructed phylogenies using Bayesian inference, maximum likelihood parsimony approaches. used our BI informativeness 22 morphological characters both delimit groups sections. Our results recovered paraphyletic, consequence recovery clade comprising Lecanthus sect. Achudemia Smithiella neither had adequately sampled studies. paraphyletic respect (including ) sister identified isomery between male female flowers, part number, sepal arrangement achene ornamentation being phylogenetically informative distinguish ( trend decreasing merism fruit size, correlated increase species‐richness across suggest may indicate shift pollen dispersal, dispersal becoming kinetic less reliant animals. On basis evaluation phylogenetic relationships propose new eight sections, five first time here: Angulatae Plataniflorae Tetraphyllae Trimeris Verrucosae