Think of parts of a flower attached to a receptacle as if they were leaves attached to a twig, except that, unlike leaves, the different parts of a flower are separated by very short distances. In a typical flower, the calyx, or outermost part of the flower, usually most closely resembles the leaves of the plant on which they occur. In fact, the calyx is frequently green and produces food from sunlight via photosynthesis, just as the leaves do. The calyx protects the developing flower bud in many plants. The corolla, the frequently colored part of the flower, is located just inside the calyx.
Showy corollas can attract pollinators such as insects or birds.
Wind-pollinated plants frequently have minute corollas or lack corollas entirely. The androecium is just inside the corolla. With magnification, you can see that the anther is actually made up of sacs. It is in these sacs that pollen grains are produced. Pollen grains are capable of producing sperm, the male sex cells.