Ferns are ancient plants. Their ancestors and related species dominated the earth when the great coal deposits of the carboniferous age were laid down around 300 million years ago. You might say that today's coal is largely made from the compressed remains of ancient ferns.
Today, according to The Fern Grower's Manual there are some 12,000 named species around the world with new types being regularly discovered. They range in size from the tiny to tree-like structures. Ferns propagate from spores rather than seeds, although this was not understood until 1794 when John Lindsay, a British surgeon in Jamaica, grew ferns from 'dust' collected from adult plants.
Ferns: Popular Victorian Plants