Comparative morpho-anatomy of the female flowers in species of the amazonia palm genuS Oenocarpus Martius

Among the Amazon native palm species with potential economic use are those of genus Oenocarpus Mart., tribe Euterpeae, considered one of the most ecologically and economically important tribes within Arecaceae. Considering that floral structure provides a wide range of morphological characters with complex evolutionary patterns, and that morphology and anatomy contribute to our better understanding of physiology and ecological, taxonomic, and phylogenetic relationships, we studied female flowers of four Oenocarpus species (O. bacaba, O. bataua, O. minor and O. mapora) occurring in the Amazonas state, Brazil, representing most species in the Brazilian Amazon. Morphoanatomy indicates that an oval shape pattern is the main trend for the flowers of the genus, with specific differences observed in stigmas, whereas anatomy, histochemistry, and SEM analyses revealed that the main differentiating characteristics are restricted to the perianth. Geometric morphology helped establish similarities and distances between species in shape of the floral outline. Anatomy and histochemistry show that there is a pattern of structural and metabolic organization within the genus, regardless of environment, reinforcing the putative affinity between the species.