The two reproductive whorls of a flower are the androecium and the gynoecium. The androecium is the male reproductive whorl made up of stamens; each stamen has an anther that produces pollen grains (which contain the male gametes). The gynoecium (pistil) is the female reproductive whorl made up of one or more carpels; each carpel has an ovary containing ovules (which contain the female gamete, the egg), a style and a stigma that receives the pollen.

A typical mature embryo sac (female gametophyte) is 7-celled and 8-nucleate. At the micropylar end there is the egg apparatus consisting of one egg cell and two synergids (with special thickenings called filiform apparatus). At the chalazal end there are three antipodal cells. In the centre there is a large central cell containing two polar nuclei. Thus, although there are 8 nuclei, there are only 7 cells because the central cell has two nuclei.

Pollination is the transfer of pollen grains from the anther to the stigma of a flower. Self-pollination (autogamy) is the transfer of pollen from the anther to the stigma of the same flower or another flower of the same plant; it maintains parental characters. Cross-pollination (allogamy) is the transfer of pollen to the stigma of a flower on a different plant of the same species; it brings about variation. Cross-pollination is carried out by agents such as wind, water, insects and birds.