Pollination is defined as the transfer of pollen grains from the anther (containing the pollen grains) to the stigma.
There are 2 methods of pollination – insect pollination and wind pollination. Read more in the blogs on insect pollinated flowers and wind pollinated flowers.
Shown below is an example of pollination in the Crinium lily plant. Notice the orange pollen grains sticking onto the stigma and style of the flower. 
There are two types of pollination – self pollination and cross pollination.
Self-pollination is the transfer of pollen grains from the anther and stigma of the same flower or of a different flower on the same plant. Cross pollination is the transfer of pollen grains from one plant to the stigma of a flower in another plant of the same species.
Studies have shown that only 10–15% of flowering plants are self-fertilizing. For example, orchid flowers are bisexual and are able to be self-pollinated/fertilised. The photograph below taken at the Singapore Botanical Gardens shows a typical Orchid (Aranda Prapin yellow) with two white pollen sacs at the top and the stigma next to it in the same tube. The pollen grains can be self-pollinated by wind, insect or even by hand!
After successfully landing on the stigma by insect or wind pollination, the pollen grain will germinate, carrying the male gamete down the style to reach the ovary, which contains the ovum or female gamete.
Shown below is the long style of the Spider lily (same family as Crinium lily) flower, which the pollen grain must germinate in order to reach the ovary.
Fertilisation takes place when the male gamete fuses with the female gamete, and the seed is formed. The ovary turns into the fruit.
The photographs below shows the fruit formed for the Peacock Flower / Caesalpina pulcherrima (after successful pollination and fertilisation).
The female Lemon Immigrant Butterfly / Catopsilia pomona pomona visits the Peacock Flowers and probably aids in its pollination.
purebiologyrs 