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What are the four main organs of a complete flower?
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Plant reproductive system
A large bumblebee (Bombus species) pollinating a teasel flower head (Dipsacus species).
A complete flower is composed of four main organs attached to the floral stalk by a receptacle. Arranged from the base upward, these organs are:
- Sepals: The outermost layer, which is usually green and serves to protect the flower bud. Collectively, they are known as the calyx.
- Petals: Located internal to the calyx, these are generally brightly colored to attract pollinators. Collectively, they are known as the corolla.
- Stamens: The male reproductive structures, collectively called the androecium, which produce pollen.
- Carpels: The female reproductive structures located at the center of the flower, collectively called the gynoecium. These enclose the ovules and eventually develop into fruit after fertilization.1
While the sepals and petals are considered accessory parts or sterile appendages, the stamens and carpels are directly involved in sexual reproduction.1