Ferns first appear in the fossil record about 360 million years ago in the late Devonian period, but many of the current species did not appear until roughly 145 million years ago. Ferns are basically flowerless plants that have feathery or leafy fronds. Plus, they are classified by their structure and spore-bearing parts, not to mention that they vary in size from tiny mosslike growths to large tree ferns with a stout trunk. As a matter of fact, ferns are not as important economically as seed plants, yet they have considerable importance in some societies, considering some varieties are used for food. You'd be surprised if you knew that the humble fern leaves actually contain high amounts of protein and minerals like zinc, potassium and calcium. Furthermore, they are also an excellent source of vitamin A, vitamin C and some vitamin B complex. In addition, ferns support bone health, promote optimal function of nerve system and promote healthy vision.