Development of female gametophyte :
The female reproductive part of a flower is gynoecium. which consists of three parts-stigma, style and ovary. The ovules are formed in the ovary and attach to it through placenta. The ovule is surrounded by one to two protective layers are called integuments, leaving a small opening at one end termed as a micropyle. The stalk of the ovule is called funiculus. The ovule is composed of multi-celled cellular tissue called the nucellus. A hypodermal cell of nucellus toward at the micropylar end enlarges and becomes a megaspore mother cell that undergoes meiosis to form a linear tetrad of four megaspores. Out of four, only one remains functional and three megaspores degenerate. The functional megaspore undergoes three successive mitotic divisions to form eight nuclei, which arrange themselves into three groups. Three nuclei migrate towards the micropylar end and form the egg apparatus. Other three nuclei form antipodal cells at chalazal end. The remaining two nuclei come together as polar nuclei which fuse to form secondary nucleus in the centre of the embryo sac.