The stigma is a part of the pistil, which is the female reproductive organ of a flower). It is located at the top of the pistil and is a sticky surface that is receptive to pollen). The stigma plays a crucial role in the fertilization process of a flower. When pollen lands on the stigma, it germinates and sends down a pollen tube that grows through the style and into the ovary, where it fertilizes the ovules. The stigma is adapted in various ways to catch and trap pollen, such as having hairs, flaps, or sculpturings). It can also play an active role in pollen discrimination and self-incompatibility reactions, which reject pollen from the same or genetically similar plants). Additionally, the stigma rehydrates the pollen and assists it in moving down the style.