Palynological characterization and taxonomical delimitation of the subgenera within Passiflora L. (Passifloraceae: Malpighiales), the largest genus of lianas in the Neotropics

Passiflora L., the largest genus of Neotropical lianas, belongs to the family Passifloraceae and encompasses 615 accepted species as concluded in the present research. Historically, various taxonomic classifications have been proposed for the genus. One such proposal divided the genus into 23 subgenera. Subsequent revisions reduced this number to four and later expanded it to the six currently recognized subgenera. Recent phylogenetic analyses using molecular markers have confirmed the monophyly of these subgenera. However, no study has used pollen characteristics for the taxonomic delimitation of subgenera of Passiflora. Given the importance of pollen morphology in taxonomy, this study aims to present taxonomic and palynological descriptions, illustrations, an identification key, and a list of species of the subgenera Astrophea, Deidamioides, Decaloba, Passiflora, Tetrapathea, and Tryphostemmatoides.