April 18

winter aconite Photo Credit: Rudi Riet.

Science Fact

The Parts of a Flower

Most flowers are comprised of four whorls, or concentric circular arrangements of parts, that sit atop a stem: the calyx, the corolla, the androecium, and the gynoecium.

The calyx is the outermost layer of leaves of a flower. It is made up petal-like sepals, which can be green or the same color as the rest of the flower. These sepals form the outside of the flower bud and help to protect the bud. It also can help provide food for the plant.

The corolla is the main part of the flower and refers to the flower's petals collectively as a group. The corolla attracts bugs and other pollinators who help the plant reproduce, as well as protecting the inner whorls of the plant.

Together, the calyx and the corolla form the perianth.

The androecium whorl is made up of stamens. Each stamen consists of an anther atop a filament. The anther produces pollen, which contain the male reproductive cells of the plant.

The gynoecium whorl is made up of carpels or pistils, which are the female organs of a plant. Each pistil consists of an ovary, from which a style extends, ending with a stigma.

Some flowers lack one or more of these whorls, making them incomplete flowers. Those that have all four whorls are called complete flowers.

Check out some flower-related resources from Science NetLinks and our associates:

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