Flowers are reproductive organs of the plants. Be it water-meal duckweed that produces the smallest flower in the world, or Rafflesia arnoldii, the largest flower of the world, all flowers more or less have the same structural elements. To understand the function of flowers in plants, it is necessary to know the various parts of a typical flower and to understand how each of these parts contributes to the overall process of reproduction.
Pedicel is only a structural element of the flower. It can be loosely seen as a tender branch, at the tip of which a flower grows. In the case of most flowers, the pedicel is in some shade of green. Its only other function is to supply nutrition to the flower.
At the tip of the pedicel is a small cup-like structure that holds the entire flower above it. Its name, receptacle, comes from this very function that it performs. Like the pedicel, the receptacles of most flowers are also green.
Tiny leaf-like projections, called sepals, grow above the receptacle. Like the pedicel and the receptacle, the sepals of most flowers are green shaded. Sepals hold the bud until it blossoms into a flower. While this happens, the sepals open up, first outwards and then start drooping downwards. All the sepals of a flower are collectively referred to as the calyx.
From around the edge of the receptacle, and just about the calyx, are the petals. They form the most distinguishable and easily identifiable part of any flower. The two reproductive structures of the flower are nestled inside the petals: the stamens and the pistil.
Each stamen consists of a thin wire-like element, the filament, at the tip of which is a tiny bud-like element called the anther. In a single flower, there are several stamens organized in a circular pattern. Each anther contains pollen, a fine powdery substance which, in turn, holds the male gametes (sperm cells) within it.
The pistil, a tubular structure, grows at the center of the conical structure formed by the stamens. There usually is only one pistil in each flower. The lower part of the pistil is a bulb-like structure called the ovary, which produces the female gametes (eggs), called ovules. Above this ovary is a stem-like structure called the style, at the tip of which are small globules called the stigma. In most flowers, pollen gets picked up from the anthers of one flower and deposited on the stigma of another flower of the same species. Referred to as pollination, it is the most important aspect of reproduction.