Palynotaxonomy of Passiflora supersections Coccinea and Distephana (Passifloraceae) in Brazil

The genus Passiflora is the largest Neotropical liana genus, comprising more than 600 species worldwide and 166 in Brazil; nevertheless, its infrageneric classification remains difficult to delimit. Within this genus, the supersections. Coccinea and Distephana include 17 Brazilian species, mostly red-flowered, historically treated together within Passiflora subgenus. Distephana. Their circumscription has been based primarily on leaf characters, whereas palynological data remain scarce and molecular phylogenies frequently do not recover them as distinct clades. To clarify these relationships, we examined 43 specimens covering 17 Brazilian species of the two supersections. Pollen grains were prepared by acetolysis and analyzed with light and scanning electron microscopy. Fourteen quantitative characters were measured and evaluated through multivariate analyses. The pollen is large to very large, 6-syncolpate, oblate-spheroidal, with sexine reticulate and heterobrochate. Diagnostic characters separated morphologically similar species, notably P. speciosa from P. margaritae and P. velutina from P. toxicaria, while distinctive characters such as partially duplicolumellate muri in P. dolorosa reinforced species-level recognition. These results demonstrate that palynological evidence is effective for distinguishing species. However, within the examined sampling and for the variables measured in this study, the qualitative and quantitative data do not support their recognition as separate supraspecific taxa.