Ferns are plants that do not have seeds; they do not grow flowers as well. These plants are known to reproduce through their spores. On the other hand, gymnosperms do have seeds; the seeds are not inside an ovary, though. Gymnosperms make use of their seeds for procreation. Examples of this include cycads and conifers. Ferns are classified under the division of the family Pteridophyta.
Gymnosperms are divided into four divisions, which are pinophyta (conifers), Cycadophyta, Gnetophyta, and ginkgophyta. Examples of the Bryophyta are the pine trees, and it happens to be the biggest of the four divisions.
Actually, ferns have been noted to be the larger group of plants with about twenty thousand different species, whereas there are not up to a thousand species of gymnosperms. The stages of the gametophytic life cycle between gymnosperms and ferns are also different, as ferns are noted to have complex surviving gametophytes, which is not so for the gymnosperms.