Resolving intergeneric relationships in the aervoid clade and the backbone of Ptilotus (Amaranthaceae): evidence from whole plastid genomes and morphology

The informally named “aervoid clade” in Amaranthaceae includes ~134 species in five genera: Ptilotus (~120 spp.), Aerva (11 spp.) and the monotypic Nothosaerva, Omegandra, and Kelita. The relationships of the small aervoid genera to the large genus Ptilotus, and relationships between major clades within Ptilotus, are poorly resolved. The aims of this study were to: (1) elucidate relationships between genera and within Ptilotus using a phylogenomic approach; (2) identify morphological characters within each genus to help delimit generic boundaries; and (3) provide an updated taxonomic framework for the aervoids. A well-supported coding DNA sequence (CDS) phylogeny was constructed for 36 aervoid and 5 outgroup species based on 69 gene sequences derived from assembled whole-plastid genomes. The CDS tree was used to constrain relationships on a larger phylogeny based on Sanger-sequenced ITS and matK for 135 taxa, comprising near-comprehensive sampling within the aervoids. Both datasets were analysed using maximum likelihood and Bayesian inference. Morphological characters were assessed from herbarium specimens. Our study demonstrates that Aerva is polyphyletic; this is resolved by reinstating Ouret and erecting a new genus, Paraerva. Kelita is found to be deeply nested within Ptilotus and is formally synonymised. The well-resolved phylogeny of Ptilotus presented here will inform future studies in biogeography and character evolution. A taxonomic treatment is provided for all aervoid genera, and new combinations are made

Evolution of flower morphology and a natural re-arrangement of Calyceraceae

Calyceraceae is a small South American family sister to Asteraceae. Previous phylogenetic analyses revealed that Calyceraceae genera are para- or polyphyletic. Fruit and inflorescence characters used historically as diagnostic in Calyceraceae taxonomy have proven unreliable in defining natural groups. Surprisingly, flower morphology does not appear in diagnoses of Calyceraceae genera, and its diversity and evolution has remained unstudied before now. Based on phylogenetic analyses using six molecular markers and an almost complete sampling of the family (43 of 46 species), we propose a taxonomic re-arrangement of Calyceraceae. In the search for diagnostic morphological characters, we studied flower structure diversity and optimized 12 discrete characters by maximum parsimony and maximum likelihood to reconstruct floral evolution in the family. Calyceraceae species are arranged in eight genera (three monotypic, five with 6 to 13 species). Two genera are new (Anachoretes, Asynthema), one is reinstated (Leucocera), with the remaining five emended (Acicarpha, Boopis, Calycera, Gamocarpha, Moschopsis). Flower morphology is notably diverse but provides only a few diagnostic features. Many floral attributes likely reflect selection for pollination or fruit dispersal rather than phylogenetic affinity. In the context of this taxonomic revision, we include a key to genera, new and emended diagnoses, and new combinations.Fil: Pozner, Raúl Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Johnson, Leigh. University Brigham Young; Estados UnidosFil: Denham, Silvia Suyai. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin