The CMI was calculated only for the progenitor cells in primordial region P-1, P-2 (only five cells that will ultimately constitute a predominant part of the flower bud are considered) and the intervening region (IR) located between them (progenitors for the P-4 region) (Fig. 6A; Fig. 9A,B). The CMI observed in individual sectors during successive 24 hour intervals is expressed as percent increase in cell number over initial number of cells at 0 hours.