Equisetales

Equisetaceae, also known as the horsetail family, is a family of ferns and the only surviving family of the order Equisetales, with one surviving genus, Equisetum, comprising about twenty species.

Equisetales is an order of subclass Equisetidae with only one living family, Equisetaceae, containing the genus Equisetum (horsetails), as well as a variety of extinct groups, including the tree-like Calamitaceae.

Calamitaceae is an extinct family of equisetalean plants related to the modern horsetails, known from the Carboniferous and Permian periods. Some members of this family like Arthropitys attained tree-like stature, with heights over , with extensive underground rhizomes. They were largely found in wetland environments.

Equisetites is an extinct genus of vascular plants within Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds. The genus was named by Sternberg (1833) and contains at least 40 named species and two unnamed species, with the earliest known species being E. hemingwayi from the Westphalian of Yorkshire, England, though the affinity of this genus to modern Equistaceae is uncertain.