On a plant, the stigma is the site where the germination of the pollen grains occur. The stigma sits on the top part of the pistil. Along with the style and ovary, the stigma is part of the flower's structure called the pistil.
In flowers, the pistil is the female part, and the male part is called the stamen. The ovary, located at the bottom part of the pistil, is where ovules are produced, while the style is a tube-like structure that leads to the stigma.
In the stamen, pollen is produced in the anther. Pollination occurs when pollen lands on the stigma. Pollen travels down the style through a pollen tube to fertilize the ovules.