The principal purpose of a flower is the reproduction of the individual and the species. All flowering plants are heterosporous, that is, every individual plant produces two types of spores.
While land plants have existed for about 425 million years, the first ones reproduced by a simple adaptation of their aquatic counterparts: spores. In the sea, plants—and some animals—can simply scatter out genetic clones of themselves to float away and grow elsewhere. This is how early plants reproduced.