While many flowers exhibit pentamerous symmetry with five petals, this is not a universal characteristic across all flowering plants. The number of floral parts varies significantly, with monocots often displaying parts in threes and eudicots typically having four or five. This variation originates from the early evolution of angiosperms, where different major clades established distinct numbers of "slots" for organ development within whorls. The precise number of petals is not genetically dictated but rather influenced by the dynamics of growth, such as the size of the meristem and the timing of organ development, which collectively determine how many parts can form.