Evolution of floral dimorphism in a cleistogamous annual, Impatiens noli-tangere L. occurring under different environmental conditions

The resource allocation models for the evolution of a mixed production of cleistogamous and chasmogamous flowers were tested in four natural populations of Impatiens noli-tangere L. When we incorporated the estimated parameter values into our basic model, under the assumption that the environmental conditions did not change through the reproductive season, the model predicted the obligate chasmogamy in all four populations. However, including the fluctuation of the fertility of chasmogamous flowers in the model, the seasonal switching of chasmogamous and cleistogamous flower production becomes an evolutionary stable strategy, which explains the reproductive behavior of the individuals in two populations. Only after the relationship between the geitonogamy of chasmogamous flowers and the number of chasmogamous flower production was considered in the model did the simultaneous production of both of the dimorphic flowers become an evolutionary stable strategy. Further, the complete model clarifies the reproductive behavior of the individuals in the other two populations.