Ferns have been with us for more than 300 million years and in that time the diversification of their form has been phenomenal. Ferns grow in many different habitats around the world. The ferns were at their height during the Carboniferous Period (the age of ferns) as they were the dominant part of the vegetation at that time. During this era some fern like groups actually evolved seeds (the seed ferns) making up perhaps half of the fern like foliage in Carboniferous forests and much later giving rise to the flowering plants. Most of the ferns of the Carboniferous became extinct but some later evolved into our modern ferns. There are thousands of species in the world today.