What are the main signs of gymnosperms?

Gymnosperms were the first plants to have seeds. They are often called bare seeds because they have no flowers and their seeds develop on the surface of the reproductive structures of plants, rather than being contained in a specialized ovary.

Gymnosperms are a group of plants with the following unique characteristics:

they have no outer covering or shell around their seeds;
they don’t produce flowers;
they don’t produce fruit;
they are pollinated by the wind.