In the life cycle of plants, fertilization is invariably associated with sexual reproduction and therefore represents the genetic switch that initiates the diploid, or the sporophytic, phase of development. The history of research into fertilization in angiosperms may be said to have begun with the discovery of syngamy, or the actual fusion of the male and female gametes, by Strasburger (1884) and of double fertilization by Nawaschin (1898) and Guignard (1899). The latter two investigators called attention to the streamlining of the male gametophyte's economy by providing light microscopic evidence for the fusion of one sperm with the egg cell to form the diploid zygote and of the other sperm with the polar fusion nucleus of the central cell to generate the triploid endosperm. In spite of an abundance of studies on the development of the male and female gametophytes and on postfertilization events in angiosperms in the years following these discoveries, relatively few investigators have ventured into the area of fertilization research. This has led to the unenviable situation that, as a biological process, fertilization in angiosperms has remained as an unknown black box. The paucity of information on fertilization is undoubtedly related to the fact that events leading to the egg–sperm encounter take place in the privileged interior of the multicellular ovule, where, hidden from the eye, they are not prone to experimental assault and to the technical difficulties that have so far prevented the development of an exovulo in vitro fertilization system.