Interactive key for species of Rudgea Salisb. (Rubiaceae) that occur in Brazil with emphasis on domatia classification

ABSTRACT Rudgea Salisb. (Palicoureeae, Rubiaceae) comprises about 150 neotropical species, with one of its diversity centers in the Atlantic Rainforest. Species of Rudgea are usually identified by a combination of characteristics, including the presence or absence of a structure called domatia. Interactive keys, alongside the domatia descriptions, could be excellent tools for the identification of the Rudgea species. Therefore, the objective of this study was to create an interactive key to Rudgea and describe its domatia types. The characteristic with the highest differentiation power was the stipule type, whilst the type of domatia was the second most powerful between the species that possessed it. Excluding this work, other studies involving domatia descriptions in this family and genus are rare, therefore, new studies are necessary, since the structure shows a potential for identification and differentiation of other taxa of this family.