Phyllotaxis in the Oil Palm: Arrangement of Male/Female Spikelets on the Inflorescence Stalk

The geometry of spikelet arrangement along the massive maleand female inflorescences of this monoecious palm is investigatedthrough techniques of phyllotaxis measurement (Equivalent phyllotaxisindex or E.P.I. Essentially there is little apparent differencewhether E.P.I. values from male inflorescences or female areconsidered. In both sexes E.P.I. estimates vary in a curvilinearmanner along the inflorescence length, higher values being obtainedtoward the broad base. Based on this pattern one value-over-allinflorescence E.P.I. is suggested to compare bunches emanatingfrom different treatment or genetic sources. It is also shownthat over-all bunch (inflorescence) E.P.I. varies systematicallywith palm age, being low in young palms and rising to asymptoticlevels in c. 11-year-old palms. Some physiological explanationsfor this latter observation are put forward, and some possibleapplications in cultural and genetic studies are suggested.Attention is also given to describing the results in terms ofFibonacci contact parastichy systems.