The reproductive biology of two poorly known relatives of the fig (Ficus ) and insights into the evolution of the fig syconium

Abstract

We conducted the first detailed investigation of the floral architecture and reproductive biology of two species from the genus Dorstenia, which are poorly known relatives of Ficus (Moraceae). Our aims were to extend and refine knowledge of the understudied genus Dorstenia and to explore possible insights into the evolution of the fig syconium. We characterised four key stages of floral development using light microscopy, scanning electron microscopy and histological staining. Reproductive biology was found to be complex and species-specific. Both study species are monoecious and produce an inflorescence of minute male and female flowers. Protogyny, associated with a spatial separation of male and female flowers and asynchronous stamen development, was species-specific, as was seed set. Our results reveal novel insights into the complex reproductive biology of an under-studied genus in the family Moraceae. We propose that exploring the reproductive biology of Dorstenia and other poorly known Ficus relatives will provide insights into the evolution of the fig syconium – the unique reproductive structure of this economically and ecologically important genus.