Synopsis of Argythamnia, Chiropetalum and Philyra (Euphorbiaceae) in South America

ABSTRACT As part of the systematic study of the tribes Ditaxeae and Adelieae (Acalyphoideae-Euphorbiaceae), here we compile and present a taxonomic synopsis for the South American taxa of Argythamnia, Chiropetalum, and Philyra. We recognize 22 species for Argythamnia, including one herein described as a new species, 20 species and one variety for Chiropetalum, and a single species for Philyra. We also designate 22 lectotypes, a new synonymization and a status novum, in addition to keys for each genus, distribution maps for all taxa, analysis of collection density in South America for each genus, and taxonomic and ecological comments for all taxa.