Contained in the coal swamps of the Carboniferous were the horsetails. Horsetails were very much like trees, although they were much less woody. One example of horsetails is the species of Calamites. These grew to a soaring height of 60 feet. Another species was Sphenophyllum. The only horsetails today are small, woodier specimens.

Paleozoic Era: Botanist's List