Four different types of male flowers exist . On the basis of these flower types , the genus has often been split into four genera — a more narrowly defined Attalea , Orbignya , Maximiliana and Scheelea . The species sometimes referred to Orbignya have coiled anthers , while the other groups have straight ones . The petals of those placed in Maximiliana are much shorter than the stamens , while those placed in Scheelea and a more narrowly defined Attalea have petals that are longer than the stamens . Five species do not fit easily into any of these groups ; this fact has been used as an argument in favour of considering this group a single genus .