Horsetails

Reconstruction of Calamites After Hirmer, 1927, in Stewart and Rothwell, 1993.

Horsetails (Division Sphenophyta)
Horsetails are also known as bottle rush or scouring rush. They look like long jointed tubes, with whorls of narrow leaves around the stems. Living species, all in the genus Equisetum, do not usually grow much taller than a person, but the fossil horsetails were much taller. The fossil horsetail Calamites could be as tall as 20 m. Like other plant fossils, different parts of the same plant may have different biological names, because they are seldom found preserved together on one fossil.

· Calamites, the stem
· Asterophyllites, leaves
· Annularia, leaves
· Sphenophyllum, leaves
· Equisetites, horsetails similar to modern Equisetum