A fern that has a trunk-like stem up to 10 m tall with the leaves located at the top. There are two principal families, Dicksoniaceae with three genera and about 30 species found in tropical, subtropical, and temperate regions mainly in the southern hemisphere, identifiable by having the stem covered with hairs, and Cyatheaceae with five genera and more than 600 species with a pantropical distribution, in which the stems are covered by scales.