A group of three cells in the seven-celled embryo sac of an angiosperm (flowering plant) consisting of the egg cell and two associated cells called synergids. The egg apparatus is located at the end of the embryo sac closer to the micropyle (the opening through which pollen nuclei enter the ovule.) The synergids are thought to help direct the pollen nucleus to the egg cell as part of the process of double fertilization characteristic of angiosperms. The synergids degenerate after the egg cell has been fertilized. See more at embryo sac.