While major parts of a flower are both structural and reproductive in nature, each component has its own purpose. Although flower species can vary widely in their appearance, nearly all have the same or similar basic parts, including the perianth, the pistil or carpel and the stamen. Some flowers, however, may lack either the pistil or the stamen, making them "male" or "female" flowers and requiring cross-pollinization to bear fruits and seeds.
The perianth is made up of the outer flower parts, including the petals (corolla) and sepals (calyx). The sepals are the outer ring of leaf-like parts that grow on the base of the flower. The sepals protect the other flower parts when the flower is closed, prior to blooming. The petals are the inner set of leaf-like parts that are usually brightly colored. The petals exist to attract insects for pollination.
Pistil or Carpel
The pistil or carpel is comprised of several parts, including the stigma, style and ovary, which is divided into the placenta and ovules. The pistil is the female reproductive organ of the flower located at the very center of the bloom. The ovary is the bulbous portion at the base of the pistil, which develops into the fruit. Contained within the ovary are one or more female eggs or ovules, which turn into the seeds. The style is the long stalk that connects the ovary with the stigma. The stigma is the topmost part of the pistil and receives the pollen grains.
The stamens are the male reproductive organ of the flower, containing the filament, anther and pollen grains. The stamens are usually on either side of the pistil and inside the petals. The filament is the thin stalk that connects the pollen-containing anthers to the base of the flower. The anthers are typically yellow, oblong, sac-like structures that produce the pollen grains, which are the male reproductive cells. The pollen grains are barely visible individually but resemble a powdery substance when seen in larger quantities.