XVI International Botanical Congess

From a comprehensive pollen study of the Piptadenia group, the morphological and structural pollen characterization of the genus Adenopodia sensu Brenan species is analyzed. These are polyads with variable shape, pollen grains number and small size with tendence to flat tetratetrads with tetrads in cross distribution (decussed) and ellipsoidal-rhomboidal outline shape, pores in angular position and thin exine (1 |m). Structural characters of the exine (vestigial foot layer and white lines in lamellar endexine) demonstred affinity with the genus Piptadenia s.l.. Apertural areas with a reduced cover of the ectexine and subdistal-proximal position demonstred no affinity with species of genus Mimosa (ser. Glanduliferae Benth). The systematic position of A. uaupensis, A.floribunda, A. minutiflora and A. peruviana is discussed. These, with Adenopodia polyad type differs in other morphological and structural characters. In order to interpret the relationships within Piptadenia group morphologycal and structural phylogenetic trends are suggest.