Unlike angiosperms, or flowering plants, whose seeds are enclosed by fully developed ovaries, or fruits, gymnosperms, or any vascular plant, reproduce by the use of an exposed seed, or ovule.
Gymnosperms don't have an ovary, hence they can't reproduce.
As a result, they develop seeds that aren't encased in the ovary, resulting in naked seeds.
There are no flowers on these plants to distinguish the ovary,style, or stigma.
As Gymnosperms lack ovaries, they do not have multiple fertilization, have male and female gametophytes on cones rather than flowers, and pollination is carried out by wind rather than animals, unlike angiosperms.