Calamites — Calamites
Calamites Verisimilus, Wikimedia Commons, CC BY 3.0

Plant

Calamites

Giant horsetail

Calamites is the Carboniferous tree-sized horsetail whose ribbed, jointed pith casts are common in coal-measure sandstones and Mazon Creek concretions. Stem casts with the vertical ribs and nodes are cheap and often large; Annularia and Asterophyllites are its foliage. Pith casts are frequently mistaken for 'petrified bamboo'.

PhylumTracheophyta
ClassEquisetopsida
OrderEquisetales
FamilyCalamitaceae
GroupPlant
Rank (PBDB)genus· Paleobiology Database
AuthorSuckow 1784· Paleobiology Database
Classification (PBDB)Pteridophyta › Polypodiopsida › Equisetales › Calamitaceae· Paleobiology Database
Range (PBDB)330–171 Ma· Paleobiology Database
PBDB occurrences349· Paleobiology Database

Elsewhere

Cite this article

Stratum Study. "Calamites" (Taxon). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/taxa/calamites. Accessed 2026-09-20.

@misc{stratum-calamites,
  title        = {Calamites},
  author       = {{Stratum Study}},
  howpublished = {\url{https://stratum.black/study/taxa/calamites}},
  year         = {2026},
  note         = {Taxon article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, pbdb, wikidata, commons, smithsonian. Accessed 2026-09-20.}
}

Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.