Equisetales

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.

Equisetales Temporal range: Late Devonian – Present PreꞒ Ꞓ O S D C P T J K Pg N
Equisetum sylvaticum in France
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Division:	Polypodiophyta
Class:	Polypodiopsida
Subclass:	Equisetidae
Order:	Equisetales DC. ex Bercht. & J. Presl
Families
†Archaeocalamitaceae †Calamitaceae Equisetaceae †Phyllothecaceae †Neocalamites †Nododendron †Schizoneura †Spaciinodum

Classification

In the molecular phylogenetic classification of Smith et al. in 2006, Equisetales, in its present circumscription, was held to be the sole member of class Equisetopsida.^[1] The linear sequence of Christenhusz et al. (2011), intended for compatibility with the classification of Chase and Reveal (2009)^[2] which placed all land plants in Equisetopsida,^[3] made it the sole member of subclass Equisetidae, equivalent to Smith's Equisetopsida.^[2] The placement of Equisetales in subclass Equisetidae has subsequently been followed in the classifications of Christenhusz and Chase (2014)^[4] and PPG I (2016).^[5]

The fossil record includes additional extinct species in Equisetaceae and the extinct families Calamitaceae, Archaeocalamitaceae and Phyllothecaceae.^[6][7]

Cladogram after Elgorriaga et al, 2018.^[8]

Equisetales	Archaeocalamitaceae Protocalamostachys Peltotheca Paracalamitina Cruciaetheca Calamitaceae Neocalamites Equisetaceae Equisetites arenaceus Spaciinodum Equisetum