Pollination is the mechanism by which pollen grains shed from the anther are transferred to the stigma of the pistil.
Pollination requires pollinating agents which can biotic(animals and insects), and abiotic(wind and water).
Cross-pollination:
Cross-Pollination is referred to as the complex type of pollination during which the pollen grains are transferred from the anther of one flower to the stigma of another flower.
Cross pollination are of two types:
Xenogamy
Transfer of pollen grains from anther to stigma of different plant is known as Xenogamy
This type of pollination creates genetically diverse plants.
Examples : Squash, onion, spinach.
Geitonogamy
In Geitonogamy transfer of pollen grains from anther to stigma of another flower of same plant takes place.
Geitonogamy do not creates genetic diversities as pollen grain comes from same plant