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)K. Sternberg, von Graf. (1833). Versuch einer geognostisch-botanischen Darstellung der Flora der Vorwelt, Heft V. Prag (1833–1838) and contains at least 40 named species and two unnamed species,Zauer, V. V. (1965) The Permian flora of Solikamsk. Trudy Vsesoyuznyy Nauchno-Issledovatel'skiy Geologorazvedochniy Neftyanoy Institut (VNIGRI). Paleophytological Collection.(Samoilovich, S.R., editor) Vol. 239 p. 53- 78 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.
Systematics Equisetites is a "wastebin taxon" uniting all sorts of large horsetails from the Mesozoic; it is almost certainly paraphyletic and would probably warrant being subsumed in Equisetum. But while some of the species placed there are likely to be ancestral to the modern horsetails, there have been reports of secondary growth in other Equisetites, and these probably represent a distinct and now-extinct horsetail lineage. Equicalastrobus is the name given to fossil horsetail strobili, which probably mostly or completely belong to the (sterile) plants placed in Equisetites. (2005): Equisetites aequecaliginosus sp. nov., ein Riesenschachtelhalm aus der spättriassischen Formation Santa Clara, Sonora, Mexiko [Equisetites aequecaliginosus sp. nov., a tall horsetail from the Late Triassic Santa Clara Formation, Sonora, Mexico]. Revue de Paléobiologie 24(1): 331–364 [German with English abstract]. PDf fulltext
Ecology Equisetites likely reproduced via the spore-bearing strobili which have been preserved in some specimens, and has also been proposed to be capable of asexual Vegetative reproduction via shed twigs and adventurous roots.
References