Box 1
Solving a ‘Frankenstein type’: nomenclatural and taxonomic approaches to deal with admixture. Typification is the main nomenclatural act to solve a nomenclatural admixture. According to Shenzhen Code (
Turland et al. 2018), if a type is found to belong to more than one taxon, the name must remain attached to the part (specimen as defined in Art. 8.2) that corresponds most nearly to the original description or diagnosis (Art. 9.14) by the designation of a lectotype (Art. 9.3 and Art. 9.11). When the original description/diagnosis is itself taxonomically mixed, as in the case of
Mimosa asperoides, the use of the protologue to guide the lectotypification may be compromised. A solution would be to conduct a comparative taxonomically analysis of the fragments to find features that underline the differences among the species involved in the admixture. This analysis may result in an amended circumscription (emend., Rec. 47A.1), in which it is possible to perform the corrections and to include relevant information previously not cited in the description, such as new diagnostic features. If after this analysis, the original material is demonstrably ambiguous and cannot be critically identified for purposes of the precise application of the name to a taxon, an epitype should be proposed under the Art. 9.9 to help the interpretation of that name; considering at least if the specimen has a similar locality, habitat, and morphological details to those mentioned in the protologue (
Turland 2019;
Lendemer 2020). On the other hand, if the lectotype is unambiguous, but incomplete, it is not appropriate to designate an epitype (see
Box 1, scheme below).
Figure 1
Detail of the identification tag of M. asperoides Izag. & Beyhaut isotype, illustrating the historical evidence of taxonomic confusion caused by specimen admixture; which was highlighted by Burkart in 1948, when he considered this specimen as a putative hybrid (Photo from F. Schmidt-Silveira).
Figure 2
Comparative morphological analysis of Mimosa asperoides and M. axillarioides leaflets, showing that some leaflets from the fragments of the designated holotype and isotype of M. asperoides (A, B) have consistent morphology with M. axillarioides (C); while other leaflets are indeed from M. asperoides (D) when comparing its morphology with non-mixed material from the M. asperoides paratype (E) and the Brazilian collections (F). A. Leaflets from a fragment of the designated holotype of M. asperoides (MVFA barcode 0000095), whose morphology corresponds to M. axillarioides. B. Leaflets from a fragment of M. asperoides isotype (MVFA barcode 0000096) that correspond to M. axillarioides. C. Leaflets from the holotype of M. axillarioides (MVFA barcode 26745). D. Leaflets from a fragment of M. asperoides holotype (MVFA barcode 0000095), whose morphology corresponds to M. asperoides. E. Leaflets of M. asperoides paratype (Berro 5528). F. Leaflets of M. asperoides from Brazil (F. Schmidt-Silveira, 1094). Upper leaflets are from adaxial face, being usually nerveless and brighter. Lower leaflets are from abaxial face, usually 1-3 nerved and non-brighter. Scale bars of 1 mm.
Figure 3
Comparative morphological details between Mimosa asperoides and M. axillarioides, showing that the morphology and indumentum of calyx and corolla are similar in both species (A, B, C, D, E). However, they differ by the indumentum of peduncles (G, H); the arrangement of leaves on branches (F, L), by fruit type, and indumentum (I, J, K). M. asperoides: B, C, D, E, F, H, J, K, M. axillarioides: A, G, I, L. (Photos A, G, I, L from M. axillarioides holotype; Photo B from a fragment of M. asperoides holotype; Photo C from M. asperoides paratype; Photos D, E, F, H, I, J, K from F. Schmidt-Silveira, 1094). Scale bars of 0.5 mm (A-E & H) and 1mm (F, G, I-L).
Figure 4
Designated holotype of Mimosa asperoides Izag. & Beyhaut and details of admixture (mixed collection): the ‘Frankenstein type’. This original material is composed of fragments of M. asperoides (A dotted & C, here lectotypified) that presents its mainly diagnostic feature, the fruit; and M. axillarioides Izag. & Beyhaut (A not dotted & B), which does not present this feature. (Photos from F. Schmidt-Silveira).