Ferns, far from being the woodland undergrowth plant found in temperate climates, are actually found all over the world. They are simple, spore-reproducing plants, with efficient photosynthesising leaves which can flourish in a wide variety of places, from desert to drainage ditch.

They are remarkably tough. They can live on ground which is unsuitable for anything else; tolerate the presence of heavy metals; endure blazing sun and the cold of the desert night.

They are an important food plant for many smaller creatures, and have survived almost unchanged from the Carboniferous period to the present.