Taxonomic and Morphometric Studies of Taxa from the Nissolia brasiliensis and N. longiflora Complexes (Leguminosae, Papilionoideae, Dalbergieae)

Abstract

 Nissolia Jacq. comprises 32 species distributed throughout the Neotropics. Its representatives are vegetatively uniform, making floral and fruit characters essential for species delimitation. This homogeneity, however, results in unresolved taxonomic complexes, especially among species with high morphological similarity, such as N. brasiliensis (Vogel) T. M. Moura & Fort.-Perez and N. longiflora (Benth. ex A. Gray) T. M. Moura & Fort.-Perez. These taxa exhibit not only extensive intraspecific morpholog­ical variation but also imprecise delimitation. Resolving such complexes is critical for understanding biodiversity, as they obscure the actual number of species. In this context, the present study aimed to conduct a morphometric and taxonomic investigation of the N. brasiliensis–N. longiflora complex. We combined classical taxonomic approaches with multivariate analyses, specifi­cally factor analysis of mixed data (FAMD) coupled with hierarchical clustering on principal components (HCPC), using 14 qual­itative and 25 quantitative characters from 46 operational taxonomic units (OTUs). We also provide an identification key, dis­tribution maps, photographic plates, and illustrations for the investigated taxa. The results support the recognition of five species within the complex, leading to the proposal of four name reinstatements, six new combinations, and four new synonyms.