The overall aim of this research is to understand at the molecular and cellular level how cells in plant meristems are directed to specific fates. The centroradialis (cen) gene is required for apical meristem identity in Antirrhinum majus. The cen mutant causes proliferating shoots to terminate with a flower of novel symmetry. Therefore, through analysis of cen I will look at how the identity of the shoot meristem is maintained and how primordia identities are specified. By expressing cen in different meristems and tissues of a number of key species, the function of cen and its interactions will be delineated. Furthermore, novel forms of plant architecture may result from altering the expression of cen and this will have implications for how differences between species arise. The cen gene is the first example of a gene required for shoot proliferation. Its analysis will have important implications on how the diversity in plant form, seen in nature and achieved through breeding, is controlled molecularly. This study, in particular, will directly ask how such a transgene may affect flower position, shoot growth and flower symmetry.