Pollination can be classified into three different types based on the source of pollen grains. They are:
i) Autogamy: It is defined as the transfer of pollen grains from the anther to the stigma of the same flower in the same plant.
ii) Geitonogamy: It is defined as the transfer of pollen grains from the anther of one flower to the stigma of another flower on the same plant.
iii) Xenogamy: This type of pollination brings genetically different types of pollen grains to the stigma of the flower.