Two new species of the South American genus Lessingianthus (Asteraceae: Vernonieae) are described and illustrated. One of these species, Lessingianthus arctatus, bears a resemblance to L. linearis (Spreng.) H.Rob. and L. rosmarinifolius (Less.) H.Rob., but can be separated from them by its almost glabrous phyllaries, solitary heads and longer internodes. The other new taxon, Lessingianthus longicuspis, can be easily separated from L. cataractarum (Hieron.) H.Rob. and L. bardanoides (Less.) H.Rob., and other taxa of the genus, by the combination of petiolate leaves, aristate phyllaries and inflorescence bracts alternate to the heads. Four other taxa previously included in Vernonia are transferred to the genus Lessingianthus.
