Aureliana and Athenaea (Withaniinae, Solanaceae) are two genera of shrubs or small trees with centres of diversity in the Brazilian Atlantic Rain Forest. They are difficult to distinguish using gross morphology, and are traditionally segregated based on differences in fruiting calyx size. Pollen grains of all taxa were acetolysed, treated and examined with light and scanning electron microscopy, with the aim of identifying diagnostic characters. Microphotographs and illustrations of pollen grains are presented. The species analysed present small- to medium-sized monad pollen grains of varying morphology with long to extremely long colpi, and lalongate endoapertures. The analysis showed that the pollen grains of both genera are very similar, differing in size-related characters. These data contributed to the synonymisation of Athenaea within Aureliana.