Transfer of Paraguayan Eupatorium amambayense to Chromolaena (Asteraceae, Eupatorieae) with taxonomical notes

Eupatorium amambayense, an endemism of Paraguay, was originally described within Eupatorium sect. Cylindrocephalum. Nowadays, genus Eupatorium is restricted to species from North America and Eurasia, and section Cylindrocephalum is a synonym of Chromolaena (Praxelinae). The objective of the work is to determine the current taxonomic identity of E. amambayense. Detailed comparative analyses of morphological traits, the protologue and type materials have revealed that the species belongs to Chromolaena and can be differentiated from the other genera of Praxelinae, especially Praxelis. As result the transfer of Eupatorium amambayense as Chromolaena amambayensis is proposed.