Despite the contribution of phenotypic variation in floral morphologies to speciation, species diversity has been recognized by modal morphologies where variation is averaged out.

Here Kitazawa and Fujimoto show a relationship between the species-representative phenotype and phenotypic variation, by analysing quantitatively intraspecific variation of the organ numbers within flowers of Ranunculaceae and the numbers of flowers within the capitula of Asteraceae. The relationship followed a common mathematical function, showing robustness on the species-representative organ numbers.