Clarificación y Epitipificación de Tagetes iltisiana (Asteraceae, Tageteae)

Background and aims: Tagetes is an American genus that includes 50-55 species of annual and perennial, strongly aromatic herbs. As part of the integral revision of the genus, in this work we study morphology and distribution of T. iltisiana, an annual Bolivian species with a dubious taxonomic position, occasionally included in the synonymy of Tagetes laxa, an annual species that inhabits northwestern Argentina. M&M: We analyzed common herbarium specimens and we conducted field observations in Jujuy, Salta and Tucuman provinces, keeping reference vouchers at Gaspar Xuarez Herbarium (BAA). Then, we compared these materials with the protologues and type specimens of Tagetes iltisiana y Tagetes laxa. Results: Numerous important morphological characters were detected to differentiate both entities. An epitype of Tagetes iltisiana is designated. A revised morphological description of Tagetes iltisiana is presented. An illustration of Tagetes iltisiana is presented for the first time. A key to differentiate the annual species of Tagetes that inhabit north-west Argentina and Bolivia is provided. Conclusions: The synonymy of Tagetes iltisiana within Tagetes laxa is rejected, identifying them as two different species. The presence of Tagetes iltisiana in Argentina is reported for the first time, bringing the number of Argentinian species of this genus to 15.