Estudos taxonômicos em Bauhinia L. com foco no complexo de B. fusconervis (Bong.) Steud. (Fabaceae)

Abstract

Bauhinia L. is a genus of Cercidoideae (Fabaceae) with a pantropical distribution. It consists of approximately 230 species, 65 of which have been recorded for Brazil, 43 of which are endemic. In Brazil, the state of Mato Grosso is the seventh richest with 22 spp. This can be explained by the presence of a mosaic of ecosystems comprising the Amazon, Cerrado and Pantanal domains, with the Baixada Cuiabana region standing out as an ecotone area. The current classification of the genus consists of eight sections. Seven species complexes are still recognized for Brazil, of which the B. fusconervis complex stands out, as it has eight species with an almost exclusively Brazilian distribution. Therefore, this study presented a taxonomic treatment for Bauhinia in the Baixada Cuiabana (Chapter 1) and investigated the delimitation of species of the B. fusconervis complex using geometric leaf morphometrics (Chapter 2). Specimens from field collections and those deposited in the UFMT Herbarium were used. The identifications followed specific literature and were subsequently described, and an identification key produced. In total, 16 species were described in the Baixada Cuiabana, of which five are endemic to Brazil and two are restricted to the region. For the delimitation study of the B. fusconervis complex, 765 leaf images of the eight species that make up the complex were compiled. The images were processed, and eight landmarks were applied for PCA and CVA analyses using MorphoJ. The results showed that five groups can be recognized, three of them corresponding to B. candelabriformis, B. curvula and B. pulchella, and the other two with overlapping species. Analyses including only the species of the groups where there is overlap were developed by separating the samples by geographical area. We found that although there were areas that separated, we observed areas where there was only marginal overlap, and cases with at least one area that had high morphological variation to the point of overlapping all the other ellipses. Overall, in all the analyses the main variation observed was the degree of fusion of the leaflets, followed by the angulation of the leaf apex. In view of this, these taxa have either not yet finished their morphological differentiation process or are the same specific entity with great morphological variation.