Primitive, but unique

Ferns are perhaps very old plants, but they are unique in their kind. They already occur in several hundred million year old fossils. After all, it was the first plant with roots and a real vascular system. In this way the ferns managed to extract water from the ground and use it for their further development. Because of the branches of the vessels it was also possible to get the water into the tops of the feathers or leaves. Ferns do not carry flowers. They therefore do not propagate with seeds, caused by fertilization of pistils with pollen through bees, beetles, birds, wind or otherwise. 

At the bottom of the fern leaves you see small brown dots. These points in turn consist of very small balls that stick together. Each ball is a spore box (sporangia). There are many spores in that box. In ferns, several sporangia can form a cluster called sorus (plural sori). When the sporangia are ripe, they burst open. In this way millions of spores are produced per plant. The wind takes them to other places where they can finally germinate. From the spores first grows a pre-germ (prothallium), the gametophyte, on which a male and female reproductive organ are located. Under favorable conditions, sperm cells can swim from the male to the female organ to fertilize an egg cell. A new adult plant, the sporophyte, develops from the fertilized egg. 

Spores are not the only reproductive mechanism in ferns. Some ferns also form offshoots that can run far into the environment. Breeding bulbs at the top of the leaf or along the main vein of the leaf immediately form roots at the moment they touch the ground and start to lead their own lives.

Spores of many species can survive for decades - and there are indications for thousands of years - under the ground in the cool, humid and dark environment. They are brought back to life when they come to the surface again due to disturbance and are exposed to the light. A limited number of species can germinate underground in symbiosis with fungi.