Palinotaxonomia de espécies brasileiras de Pavonia Cav. (Malvoideae-Malvaceae), com ênfase nas regi？es Nordeste e Sudeste

this work aims to study the pollen grains of 26 brazilian species of pavonia cav. occurring mainly in the brazilian northeast and southeast regions, belonging to three subgenera, goetheoides, pavonia, and typhalea. pollen grains were acetolyzed, measured, and photographed under light microscope (mo), and scanning electron microscope (sem). measures were statistically analyzed according to the sample. the pollen grains were classified into two main groups based on their apertures: a) pantoporate pollen grains, with pores associated to colpoids, spinous, tectate- microrreticulate-spiculate or tectate-perforate-spiculate-granulate exine and b) pantoporate pollen grains, with pores not associated to colpoids, spinous, tectate-microrreticulate-spiculate or tectate-perforate-spiculate-granulate exine. the results obtained in the present study showed that pavonia is a stenopalynous genus, which makes it impossible to delimitate between the subgenera goetheoides and pavonia using pollen grains characters. however, the subgenus typhalea has smaller pollen grains. spine types, tectum ornamentation, exine thickness, and pore diameters were quite important for the taxonomy of this genus, allowing to distinguish the species, which has led to a pollen key.