Mature plant
Seeds are produced during the reproductive stage of a plant's life cycle. This follows the flowering and pollination stages, where the plant's reproductive organs are involved in producing seeds for dispersal and future growth.
"They have spores. These are not an exact counterpart to seeds however, they are produced asexually (require no fertilization) as ferns have a 2 stage reproductive cycle."~ Hach on Answers.com
Spores are single cells that can develop into a new organism, while seeds are multicellular structures that contain an embryo, stored nutrients, and a protective coat. Spores are produced by plants, fungi, and some protozoa, while seeds are primarily produced by seed plants. Spores are usually smaller and simpler structurally than seeds.
Seeds are produced in the ovary of a flower. After pollination and fertilization, the ovary develops into a fruit containing the seeds.
Ferns reproduce through spores instead of seeds. These spores are produced on the underside of fern fronds in structures called sori. Spores are released into the environment and can germinate to grow into new fern plants.
By Seeds.
On plants
Plant seeds are typically produced in the ovary of a flower after pollination has occurred. The ovary develops into a fruit that surrounds the seeds, providing protection and aiding in their dispersal. Once the seeds are mature, they are released from the fruit and are ready to germinate and grow into new plants.
From each Tulsi fruit two seeds are produced. Under subtropical conditions it flowers several times in the year and continuously produces seeds.
it's not
The Soviet Union produced sunflower seeds