Self-pollination takes place when the pollen from the same plant arrives at the stigma of a flower or at the ovule. There are two kinds of self-pollination, that is, autogamy and geitonogamy.
In autogamy, pollen is moved towards the stigma of the similar flower. While in geitonogamy, pollen is moved from the anther of one flower to the stigma of another flower on the similar flowering plant, or from microsporangium to ovule within a monoecious gymnosperm.