The female gametophyte is housed in the ovule. In one type of female gametophyte, there are several cells, with a total of 8 nuclei. Pollination - the plant version of copulation. There are advantages and disadvantages of each. Pollen will not germinate or the pollen tube will stop growth if both pollen and stigma have the same S allele.
Plants involve others in their sexual escapades.
In other words, plants rely on a variety of different vectors to accomplish pollen transfer. A flower is evolutionarily adapted for its mode of pollination. For example, wind pollinated flowers have little nectar or odor, reduced petals and produce copious pollen. There is intimate coevolution between flower and pollinator. Referes to the fusion of sperm and egg, occurs in ovule.