When pollen is carried from the stamens of one flower by insects, the wind, or other agency, and deposited on a stigma of another flower, the process is called pollination. If the pollen is placed on the stigma of the same flower, that would be self-pollination; and if the flower accomplishes this itself, as it frequently does, that would be automatic self-pollination. The word fertilization is often loosely used to imply the same act, but no fertilization can really take place till the pollen tube has reached the germinal vesicle in the ovule and formed a union with it.