Evolutionary and genetic factors explain why many flowers have five petals

Many flowers have five petals due to evolutionary choices made by early angiosperms, with eudicots favoring four or five floral parts per whorl. This petal number is not genetically fixed but influenced by growth dynamics. The size and shape of the floral bud's tissue and the spacing needs of developing organs determine the number of slots available for petal formation. While five petals are common in eudicots, other flowering plants exhibit different petal counts, such as threes in monocots, or may have fused, numerous, or absent petals.