Flower differentiation
Flower differentiation is a plant process by which the shoot apical meristem changes its anatomy to generate a flower or inflorescence in lieu of other structures. Anatomical changes begin at the edge of the meristem, generating first the outer whorls of the flower - the calyx and the corolla, and later the inner whorls of the flower, the androecium and gynoecium. Flower differentiation can take from only a few days (in annual plants) to 4–11 months (in fruit crops). The process is preceded by flower induction.