Apogamy is the process of development of an embryo from a haploid cell of the embryo sac, other than the egg cell. This process bypasses the normal sexual reproduction process and leads to the formation of a haploid embryo, which is genetically identical to the mother plant.

Process of Apogamy:
1. In the process of apogamy, the megaspore mother cell undergoes meiosis, which results in the formation of four haploid cells.
2. One of the haploid cells develops into the functional megaspore, which gives rise to the embryo sac.
3. The embryo sac contains seven cells, including two synergids, one egg cell, three antipodal cells, and one central cell with two polar nuclei.
4. In apogamy, one of the antipodal cells or the central cell with two polar nuclei develops into an embryo without fertilization by a sperm cell.
5. The haploid embryo develops into a new plant without fusion with any other haploid cell.

Examples of Apogamy:
Apogamy is a common phenomenon in some plant species, such as ferns and mosses. In ferns, the prothallus, a haploid structure, develops into a new fern plant without fertilization. In mosses, the haploid spores can directly develop into new plants without the formation of a gametophyte.

Advantages of Apogamy:
Apogamy provides an advantage to plants in environments where pollination and fertilization are difficult due to various factors such as a lack of pollinators or harsh environmental conditions. It also allows for the rapid propagation of plants without the need for fertilization and genetic recombination.

Disadvantages of Apogamy:
However, apogamy may lead to a loss of genetic diversity and increase the risk of susceptibility to diseases and environmental stresses. It also reduces the chances of adaptation to changing environmental conditions.