The systematic value of pollen morphology of Passiflora subgenus Astrophea (Passifloraceae)

Abstract

This study investigates and reports the pollen morphology of a selected group of Passiflora species of the subgenus Astrophea. We found that species can be grouped into five pollen types, four of which had been previously documented. The fifth new pollen type was observed in P. macrophylla. This pollen type completely lacks muri, and possesses spines and bacula on a granulate surface. All of the species of the subgenus Astrophea studied have the same type of aperture: 6-colporate with 3 lalongate endoapertures, one for each pair of ectoapertures. Multivariate analyses performed with quantitative characters showed a great degree of similarity between type I, II and V pollen, and individual distinction of type III and type IV. The pollen characters observed do not support the currently accepted taxonomic classification for the Passiflora subgenus Astrophea, but are useful for delimiting species.