In conifers, the union of the egg and sperm takes place within the female gametophyte, specifically in the ovule found inside the ovulate cone. The ovule contains the egg cell, and fertilization occurs when a sperm cell successfully enters the egg cell.
Sperm reaches the egg through a fascinating process that involves pollen. When the wind carries pollen grains from a male cone to a female cone, the pollen grain lands on the ovule. The pollen grain then germinates, growing a pollen tube down into the ovule where the egg is located. The sperm cells travel through this pollen tube, and when it reaches the egg cell, fertilization occurs, forming a zygote that eventually develops into a seed.