What is pollination? Describe its types.

(N/A) Pollination is the mechanism by which pollen grains,shed from the anther,are transferred to the stigma of a pistil. Since male and female gametes in flowering plants are non-motile,they must be brought together for fertilisation to occur.
Depending on the source of pollen,pollination is divided into three types:
$(1)$ Autogamy: In this type,pollination is achieved within the same flower. Pollen grains are transferred from the anther to the stigma of the same flower. This requires synchrony in pollen release and stigma receptivity,and the anthers and stigma must lie close to each other. It is common in bisexual flowers.
$(2)$ Geitonogamy: This involves the transfer of pollen grains from the anther to the stigma of another flower of the same plant. Although it is functionally cross-pollination involving a pollinating agent,genetically it is similar to autogamy since the pollen grains come from the same plant.
$(3)$ Xenogamy: This involves the transfer of pollen grains from the anther to the stigma of a different plant. This is the only type of pollination which brings genetically different types of pollen grains to the stigma during pollination.