The development of the spo-rophyte directly from the gametophyte, without the formation of gametes. The resulting sporophyte therefore has the same chromosome number as the gametophyte. Although there is no nuclear alternation between the generations the morphological differences persist. The phenomenon is seen in certain ferns, fungi, and algae. If male gametes are produced they are redundant although they have been shown to be capable of functioning in certain species. For example, the male fern (Dryopteris borreri) produces antherozoids that can fertilize the female gametes of related ferns. Apogamy often occurs when the gametophyte has been produced by * apospory . It may also be induced by ageing or chemical agents. The term may also refer to the development of an unreduced diploid cell of the embryo sac into an embryo without fertilization occurring (i.e. parthenogenesis). |
