Monadelpha L.J.Gillespie & Card.-McTeag., gen. nov., is described as a new member of Euphorbiaceae tribe Plukenetieae subtribe Tragiinae, to accommodate Tragia guayanensis, a species known from western Amazonas, Venezuela and, newly reported here, from Amazonas, Brazil.  The genus is unique in the subtribe for having 5-colpate pollen and staminate flowers with filaments entirely connate into an elongate, cylindrical staminal column terminated by a tight cluster of anthers.  Phylogenetic analyses based on nuclear rDNA ITS and sampling 156 accessions across the diversity of Tragiinae (all 12 genera and 77 of ~195 species) also support Monadelpha as a distinct lineage that is separate from Tragia.  A revised key to the genera of Tragiinae in South America and Central America is provided.

This package includes the archived ITS alignment and resulting MrBayes tree file for Tragiinae and outgroups from the following paper: Gillespie et al. (2020) Monadelpha (Euphorbiaceae, Plukenetieae), a new genus of Tragiinae from the Amazon rainforest of Venezuela and Brazil. PhytoKeys.