Enantiomorphy in Banksia (Proteaceae) : flowers and fruits

There is a history of discrepancy in the interpretation of floral symmetry in the genus Banksia L.f. The variation arises not just from the potential nuances of symmetry terminology, as variation is also found in the diagrams that describe it. This paper clarifies the issue of the orientation of the ovaries within a Banksia unit inflorescence. Dissection of 2400 flowers in situ from four Banksia species has revealed the Banksia unit inflorescence to be enantiomorphic (having left-right asymmetry) due to the orientation of the ovaries. The asymmetry of the ovary and its pronounced development of the anterior side in fruit formation means that fruits are also readily distinguished as having arisen from either a left- or right-handed flower.