SPHENOPSIDS
Also known as: Horsetails, Scouring rushes
Informal group: Land plants
Age range: Devonian-Recent
Found in OK: Pennsylvanian and Permian rocks; most common in eastern Oklahoma
Living plants known as "horsetails" or "scouring rushes" belong to the genus Equisetum. Equisetum, contains
about 66 species and is the only modern representative of an ancient plant group called "Sphenopsids." Sphenopsids were very
common on the edges of coal swamps during the Pennsylvanian. Three common Oklahoma plant fossils belong to this group: Calamites,
Annularia and Asterophyllites.
