In plants that reproduce sexually the pattern is similar to that of animals. In the mosses and ferns, however, the egg cells are formed in special organs called archegonia and are fertilized by sperm that are commonly flagellated and motile like those of animals. In flowering plants the ovary is situated in the base of the pistil of the flower. After fertilization by a sperm contained in a pollen grain, the zygote develops into the embryo, contained in the seed.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.