A taxonomic headache due to a ‘Frankenstein type’: solving the identity and typification of a Mimosa species

A nomenclatural type is the element to which a name is permanently linked and must consist of a gathering, or part of a gathering, of a single species or infraspecific taxon. However, sometimes more than one species may be mounted on a single herbarium sheet (‘Frankenstein type’), causing a nomenclatural confusion (admixture) in the use of a name, which creates difficulties on the delimitation of the species and application of its name (‘taxonomic headache’). This is the case of the assigned holotype to Mimosa asperoides Izag. & Beyhaut that is composed also of other Mimosa species. To solve the ‘Frankenstein type’ of Mimosa asperoides , we analyzed the original material, the protologue, and performed a morphological comparative analysis to distinguish the species involved in the admixture. These analyses allowed us to identify which of the fragments of the ‘Frankenstein type’ correspond to M. asperoides , enabling its lectotypification and providing new diagnostic features to amend its description. Finally, we reported the first citation of M. asperoides for Brazil and discussed the link between nomenclature and taxonomy to solve a taxonomic headache due to admixture.