Pollen morphology of the genera Basananthe, Deidamia and Efulensia of the tribe Passifloreae (Passifloraceae sensu stricto)

Abstract

Passifloreae is the largest tribe of the family Passifloraceae sensu stricto. Within the tribe, palynological studies are mostly restricted to the largest genus, Passiflora, given its expressive number of species. Consequently, other genera within the tribe are frequently underexplored, particularly in terms of pollen characters. Given the importance of pollen morphology for the taxonomic classification of Passifloraceae s.s., it is necessary to describe the pollen characters of Basananthe Peyr., Deidamia Noronha ex Thouars, and Efulensia C.H.Wright. The analyzed characters included dispersion unit, polarity, size, shape, aperture number, aperture type, operculum type, and sexine ornamentation. Subsequently, 10 metric variables were subjected to principal component analysis. The results showed that the studied genera could be easily distinguished based on pollen characters, confirming the importance of palynology. The pollen of all studied species, regardless of the genus, had the same aperture number and type, namely 3-colporate. Sexine ornamentation ranged from microreticulate to reticulate, without spines. Here, pollen characters of Basananthe, Deidamia, and Efulensia were compared with those of closely related genera and Passiflora, contributing to a more comprehensive and up-to-date understanding of the group. The results confirmed the importance of analyzing pollen attributes for the taxonomy of Passiflora s.s.