Taxonomic treatment, geographic distribution and preliminar conservation status of Croton sect. Barhamia subsect. Barhamia (Euphorbiaceae) in Brazil

The genus Croton (Euphorbiaceae) is an exceptionally megadiverse genus, encompassing roughly 1200 species that are predominantly distributed across tropical regions globally. For the New World, the genus is organized into three subgenera ( Adenophylli , Geiseleria and Quadrilobi ) and 31 sections, with C. sect. Barhamia standing out with its approximately 80 species. This section is currently divided into 5 subsections ( Astraeopsis , Barhamia , Medea , Micranthi and Sellowiorum ). Here we focus on C. subsect. Barhamia , where we identified a gap in knowledge. We analysed herbarium materials, original protologues, photographs of type specimens, and made observations of species in the field. We recognize 14 species in Brazil and the Caatinga as its center of diversity. Additionally, we indicate the recently described Croton ludovicensis as a member of this subsection. An identification key, detailed morphological descriptions, notes on morphological relationships, photographs of diagnostic characters, distribution maps for all species belonging of subsection, and preliminary conservation assessments are provided. These assessments highlight the importance of conservation for several species classified as ‘Endangered', such as C. aemulus , C. glandulosodentatus , C. graomogolensis , C. ludovicensis , and C. rhexiifolius .