In this type of pollination, the pollen is transferred from the anthers of one flower to the stigma of another flower. In this case, the two flowers are genetically different from each other. Cross-pollination is always dependant on another agent to cause the transfer of pollen. The agents of pollination include birds, animals, water, wind, and insects. Based on the agent of pollination, cross-pollination can be of different types:
- Hydrophilous Flowers: These flowers are pollinated by water means. The flowers are often very small and inconspicuous to other agents. They do not have any fragrance or too much color on their petals. The pollen is adapted to be able to float in water.
- Zoophilous flowers: In this type of pollination, the pollinating agents are animals like human beings, bats, birds etc. The zoophilous flowers have pollen that is designed to stick on to the body of the animal so that they can be easily carried from one flower to another.
- Anemophilous flowers: These flowers are pollinated by the agency of wind. These flowers, like zoophilous flowers, are small and inconspicuous. Another important feature of flowers that are wind pollinated is that they are very light so that they are easily carried by the wind. The pollen grains are very light, non-sticky and sometimes winged.
- Entomophilic flowers: These flowers are pollinated by insects. These flowers are often attractive to look at with bright petals and are fragrant to attract the insect visitors to them. They often have broad stigmas or anthers to allow the insect to perch on it. Many of the insect-pollinated flowers also secrete nectar which attracts bees, butterflies or other similar insects to the flowers. The pollen grains in these flowers are often spiny or have extensions that help them to stick on to the body of the insects.
- It is beneficial to the race of the plant as it introduces new genes into the lineage as a result of the fertilization between genetically different gametes
- It improves the resistance of the offsprings to diseases and changes in the environment.
- The seeds produced as a result of cross-pollination are good in vigor and vitality.
- There are any recessive characters in the lineage, they are eliminated as a result of genetic recombination.
- It is the only way unisexual plants can reproduce.
- wastage of pollen grains that need to be produced to ensure fertilization occurs.
- There is a chances that the good qualities may get eliminated and unwanted characteristics may get added due to recombination of the genes.