Pollination is the process of transfer of pollen grain from anther to stigma of the female reproductive organ. If the transfer is to a different flower of different plant then it is considered to be cross pollination. It is also called xenogamy.

If the transfer of pollen grain is between the neighboring flowers of same plant then it is called geitonogamy.

Self pollination and fertilization occurring in a closed flower is termed cleistogamy. Herkogamy is a technique to ensure cross pollination using mechanical barrier.