Parts of a Flower

• Inside the petals, which form the delicate outer casement of a flower, are the plant's reproductive organs. The stamens, which produce pollen, are the male organs. Their two parts are the filaments, which are thin fibers that extend from the base of the flower, and the bulbous anthers at the ends of the filaments, where the pollen is formed. The single female organ, called the pistil or carpal, has an opening, called the stigma, a hollow tube-like style and an ovary at the base containing ovules that will become seeds. The green leaves at the base of the flower are the sepals. They protect it when it is closed.
  
  

Reproductive Cycle

• In order to reproduce, pollen from the stamens must reach the stigma. When this happens, the stigma forms into a tube and transmits the pollen into the ovary. Individual cells from the pollen merge with cells from the ovules to create seeds. This process is called fertilization. When seeds form, the flower drops its petals and closes in on itself, eventually becoming a fruit peculiar to that species. Eventually the fruit falls from the plant or bursts open, releasing the seeds into the ground or the air. When conditions are right, they grow into new plants and begin the cycle over again.
  
  

The Purpose of Petals

• Many plants need help to transmit pollen from the stamens to the stigma, and they may rely on bees, butterflies, other insects or even small animals. Flower petals are brightly colored and fragrant to attract them. Petals have a fragrance because smell also attracts insects and animals. They come to drink the flower's nectar and, while drinking, they rub against the stamen and collect the pollen on their bodies. When they move to a different flower, they transfer it to the stigma of that flower. Some plants rely on the wind to transfer pollen. Their flowers usually aren't as brightly colored or fragrant.
  
  

Perfect and Imperfect Flowers

• Not all flowers have both sets of reproductive organs. Perfect flowers have both, but imperfect flowers have only male or only female organs. The male and female flowers may grow on the same plant, or they may grow on different plants. Plants with perfect flowers are called bisexual, and they don't depend on insects to transfer pollen. Examples are dandelions, lilies and roses. Plants with imperfect flowers are called unisexual. The plant is monoecious if it has both male and female flowers and dioecious if it has only one sex. A dioecious plant must usually be close to one of the opposite sex to reproduce.