Was the “Calamite” the first tree-like plant to grow on land? Many scientists believe so. It grew as high as 100 feet, towering above its counterparts in the earlier periods of its lengthy lifespan, which began some whopping 400 million years ago during the Devonian Period. The trunk was a woody hollow tube, lacking true bark, like modern trees. The leaves were primitive and needle like, arranged in whorls around a stem. The Calamite thrived in hot swampy tropics, particularly during the Pennsylvanian Period around 300 mya. Many of their fossils have been found worldwide including, USA, China, Canada, South America and Europe. These fossils were found in Sebastian County, Arkansas in an old coal strip mine in 1993 by Michael A. Whitkanack, who donated them to my classroom. They are actually the imprints of the Calamite’s leaves and stems which scientists refer to as trace fossils.
Scientific Name: Calamite Common Name: Horsetail / Wiskfern
Division: Pteridophyta (Ferns, reproduce by spores)
Class: Sphenopsida or Equisetopsida (means ribbed, vertical jointed stem; bamboo like in appearance)
Genus: (STEM) Calamite (LEAF) Annularia
Special Note: The Calamite may look familiar to some, as their modern descendants are the “horsetails” of today, growing in open fields and edges of woodlands, but only reaching a few feet tall. See photo below
The “horsetail” or Equisetum is an amazing living fossil related to the Calamites, being the only surviving genus from the entire class of Equisetopsida. For over one hundred million years, the Equisetopsidas were much more diverse and dominated the understory of the late Paleozoic forests. Through the millenniums, they decomposed layer by layer, transforming into the sunken coal deposits of today.