Abstract Timing of pollen presentation and ovule maturation at the level of the flower, individual and population may exert a profound influence on individual fitness and population structure. We explored the evolutionary consequences of asynchrony in flowering in a population of dichogamous plants, making use of a genetic model to represent pollen and ovule availability over time. When the model was run for 18 generations, starting from a mixed population of both early- and late flowering, protandric and protoginous genotypes, the system evolved differently according to whether genetic dominance for precocity (or lateness) was present or absent. Under the assumption of dominance, the population evolved towards a structure dominated by protandrous, late flowering genotypes. In the absence of dominance, the system seemed to attain steady state equilibrium in which both dichogamous modes coexisted in predominantly intermediate-flowering genotypes.