Flowers make their first appearance on nature's stage as buds; short stems with embryonic male and female cells provide nutrients for the young flower. Cells divide and re-divide to form the parts of the mature flower in miniature. Flower buds, like leaf buds, form on branches of perennial or deciduous plants each spring as the plant resumes its growth after dormancy. On annual plants that grow, set seed and die within one season, flower buds develop as the plant approaches maturity. Buds may form along (laterally) or at the ends (terminally) of branches or in the axis of a leaf and branch (auxiliary). Each plant has a unique genetic code that will direct its flowering differently. Some flowers, such as those of many trees, shrubs or garden herbs, will be insignificant. Some, like those of the magnolia tree, perennial rose or annual sunflower, will be spectacular blooms.
Within the bud, the female and male cells repeatedly divide to form the ovary and anthers. The female ovary contains tiny eggs, called ovules. The male anthers will carry pollen. A tube-like pistil rises above the ovary, topped by a stigma to receive the fertilizing pollen. When this sexual structure has grown to maturity, the green calyx and colored petals are forced open as the flower "infloresces" or blooms. Inflorescence signals a botanical "puberty" to surrounding insects and birds that will harvest the sweet pollen from the anthers and track it across pistils as they travel from flower to flower. Each bloom is designed by nature to attract specific species of insects and birds. Native plants seldom need to be hand-pollinated because they dress themselves in colors and petal shapes that attract native insect and animal species. The period of bloom lasts as long as needed for the ovules to be fertilized. If they are not fertilized, the ovary and anthers shrivel as the petals dehydrate and drop; the food needed to sustain the flower is needed elsewhere.
Although we gather them for their beauty, a flower's main purpose in life is to recreate the plant that bears it. The ovary of a fertilized bloom swells as its petals drop, their job of attraction successfully completed. As embryonic plants grow in fertilized ovules inside, the ovary ripens into a green, then brown pod. Or it may grow into a fleshy, edible pod that we call a fruit. The ovules grow cases to contain the plant embryo and the nutritive material to keep it over the period of dormancy. The flower's final task is to "bloom" once more. It breaks open and casts its seeds upon the ground or winds until spring rain and warm sun stimulates their germination. Its reproductive task complete, the pod fades and dries.