Tree-ferns and some other ferns with creeping rhizome stems make up the Cyatheales group of ferns (as a sub-class or order). The tree-like habit has evolved a number of times in this group. They can grow up to 20 metres tall, with their large fronds at the top.
Tree ferns are found growing in tropical and subtropical areas as well as temperate rainforests in Australia, New Zealand, and other island groups nearby. A few genera extend further, such as Culcita in southern Europe. Like all ferns, tree ferns reproduce by means of spores developed in sporangia on the undersides of the fronds.