Pollination is the process by which pollen is transferred in the reproduction of plants, thereby enabling fertilization and sexual reproduction. In spite of a common perception that pollen grains are gametes, like the sperm cells of animals, this is incorrect; pollination is a phase in the alternation of generations: each pollen grain is a male haploid plant, a gametophyte, adapted to being transported to the female gametophyte, where it can achieve fertilization by producing the male gamete (or gametes, in the process of double fertilization). As such the Angiosperm successful pollen grain (gametophyte) containing the male gametes (sperm) gets transported to the stigma, where it germinates and its pollen tube grows down the style to the ovary. Its two gametes travel down the tube to where the gametophyte(s) containing the female gametes are held within the carpel.
Contributions by Pollinator, Debivort, and Curtis Clark.