What does the sigma do on the flower?

In the context of flowers, "sigma" typically refers to the stigma, which is the receptive part of the pistil. The stigma's role is to capture and hold pollen grains during the pollination process, facilitating fertilization. It is often sticky to enhance its ability to trap pollen, which can then grow down into the ovary to fertilize the ovules. This process is essential for the reproduction of flowering plants.