A revision of the Celtis iguanaea complex (Cannabaceae) and the reinstatement of an additional species from southern South America

Studies on Celtis over the last 50 years have established the role of the pyrene in the delimitation of the species. This structure is of fundamental importance for the understanding of the genus and has recently changed the species delimitation, which was previously very broad and vague. Based on these new findings, we have investigated the Celtis iguanaea species complex. This taxonomic group was previously treated as a single species, but it included several species-level synonyms in the Neotropical region for which no modern taxonomic and nomenclatural revision is yet available. In order to correctly delimit C. iguanaea and the other species accepted here, we conducted a review of all records and herbarium specimens (types or not). The main results include (1) a modified taxonomic concept, (2) a revision of the taxonomy, nomenclature, and synonymy (with new or corrected typifications), and (3) a revision of the distribution ranges. In addition, we re-establishment Momisia tarijensis as a species from southern South America for which a new combination (Celtis tarijensis) and an epitype are proposed. In addition, Sarcomphalus punctatus is newly included in the synonymy of C. iguanaea. Finally, we provide an identification key that distinguishes C. iguanaea from all related species.