After the $8$ -nucleate stage cell walls are laid down leading to the organisation of the typical female gametopytic on embryo sac.

Eight nuclei are surrounded by cellwalls and result into cells. Three cells are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus consists of two synergid and one egg cell.

Three cells are at the chalazal end and are called the antipodals. The large central cell has two polar nuclei. Thus a typical angiosperm embryo sac at maturity through 8 -nucleate is 7 -celled. Embryo sac is produced from haploid megaspore. So it is called monosporic embryo sac.

– Function of synergid cells : The synergids have special cellular thickenings at the micropylar tip called filliform apparatus, which play an important role in guiding the pollen tubes into the synergid.