Component number of flowers is an important aspect to capture floral morphology. Beside the diversity of floral shapes, basic numbers of the components are restricted to several numbers associated with the major clades of flowering plants. The developmental and evolutionary reason of such restriction has been a question for centuries. To answer this, we employed mathematical models developed for phyllotaxis, i.e., arrangement of leaves around the stem. The model showed that basic numbers of four and five, the major numbers in the largest clade of flowering plants, appeared spontaneously and stably, suggesting that preferences in developmental process underlie the restriction.