The correct option is Stamen.
Explanation
A typical flower in angiosperms consists of four distinct whorls arranged on the thalamus: calyx, corolla, androecium, and gynoecium. The androecium and gynoecium constitute the essential reproductive organs, while the calyx and corolla are accessory organs.
Detailed Analysis:
- Stamen (Correct): The stamen represents the male reproductive unit of the flower. Collectively, stamens form the androecium. Each stamen typically consists of two parts: a long, slender stalk called the filament and a terminal, generally bilobed structure called the anther, where pollen grains are produced.
- Pistil (Incorrect): The pistil (or carpel) is the female reproductive unit of the flower. Collectively, pistils form the gynoecium. It consists of the stigma, style, and ovary.
- Sepal (Incorrect): Sepals are the individual units of the calyx, the outermost whorl of the flower. They are typically green and leaf-like, serving to protect the flower during the bud stage.
- Petal (Incorrect): Petals are the individual units of the corolla. They are usually brightly colored to attract insects and other agents for pollination.
Key Takeaway:
In floral morphology, the stamen is the male reproductive organ (androecium), whereas the pistil or carpel is the female reproductive organ (gynoecium).