Native and exotic species of Tabebuia and Handroanthus en Argentina

The most recent studies about the genus Tabebuia and Handroanthus recognize two and six native species in Argentina, and one exotic cultivated species of Handroanthus in urban streets. Nevertheless, the genera are not completely understood, because some taxonomic conflicts are mentioned for the NW of Argentina (NWA). New collections made in Salta and Jujuy, and the revision of an important number of herbarium samples have confirmed a very high variability among the populations of the NWA region, and the subsistence of conflictive situations that prevented the correct identification of the species. Consequently, we considered it was necessary to make the revision of the genus analizing comprehensive material including all the phenological phases, in order to study most characters of every plant organ (young leaves, mature leaves, inflorescences, flowers, fruits and seeds). Our results indicate that the number of native taxa of Handroanthus is seven, including a new variety, and two of Tabebuia. Besides, another cultivated species of Tabebuia was identified, so there are two exotic taxa. All the entities are described, as well as the extant variability of native populations, and their distribution ranges in Argentina are provided.