The species of Cyathea are mostly terrestrial ferns, usually with a single tall stem. Rarely, the trunk may be branched or creeping. Many species also develop a fibrous mass of roots at the base of the trunk.
The classification below follows the findings of Conant et al. in 1996. These workers concluded on molecular cpDNA and morphological evidence that a system of three clades – Alsophila, Cyathea and Sphaeropteris is the most accurate reflection of evolutionary lineages within the Cyatheaceae, Alsophila being the most basal and Cyathea and Sphaeropteris derived sister groups.