Why is double fertilization not observed in gymnosperms despite them being seeded plants?

In gymnosperms, ovaries are absent and thus seeds are present in the cones. The male and female gametophytes are present inside cones. These produce pollen and egg respectively. Through wind pollination, the pollen grains are transferred to the female cones. One of the two sperm cells produced in the pollen fuse with the egg to form the zygote. The other one degenerates. The zygote develops inside the female cone. Nourishment is provided by endosperm derived from the female gametophyte. So, the process of double fertilization is not observed in gymnosperms, though they are seeded plants.