Transfer of pollen from the anther to the stigma of the flower is called pollination. It can be of two types:
- Self-pollination
- Cross-pollination
In cross-pollination, pollen grains are transferred by some agency from the flower to the stigma of the flower on a different plant of the same species or a different species. To eliminate self-pollination and to promote cross-pollination, flowers develop following adaptations:
1. Self sterility or incompatibility
2. Unisexuality or Decline
3. Dichogamy
4. Herkogamy
5. Heterostyly