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The Primary Parts of a Flower

The often colorful and fragrant reproductive structures of flowering plants are familiar even to small children. The parts are often broadly be categorized into four parts called whorls: the calyx, corolla, androecium, and gynoecium. The calyx consists of sepals, the petals form the corolla, the androecium contains the male reproductive parts and the gynoecium contains the female reproductive parts. However, a great diversity is exhibited by flowering plants in not only the arrangement and shape of the whorls, but even in their presence or absence.

Calyx
- The bottom whorl of the flower is the calyx, consisting of the sepals. Sepals are green leaflike structures that protect the flower as a bud. After the flower opens, the sepals remain below the corolla. The stem at the base of the flower to which the calyx is attached is termed the pedicel.
Corolla
- Petals form the whorl above the calyx; this entire unit of petals is called the corolla. Bright colors, fragrant oils and nectar glands are often associated with the petals, and these form the showy displays commonly associated with flowers. A common function of the corolla is to attract pollinators--insects and other animals that carry the pollen between flowers enabling fertilization. The calyx and corolla together are termed the perianth, the nonreproductive whorls of the flower.
Androecium
- The androecium is the male reproductive part of the flower and forms the next whorl. Stamens are the principle structure of the androecium and consist of a pollen-producing tissue called the anther, atop a thin stalk called the filament.
Gynoecium
- The gynoecium (also called the pistil) forms the fourth whorl and contains the female reproductive parts. The major feature of the gynoecium is the carpel. The carpel consists of a stalk, called the style, stretching between the ovary at the base of the stigma and a sticky tissue that collects pollen at the other end of the style, called the stigma.

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