Rare Fossil Annularia from Calamites, Carboniferous, Massachusetts
AGE: Middle Pennsylvanian (300 Million Years Old)
LOCATION: North Attleboro, Massachusetts
Annularia is a form taxon. It is the name given to Calamites leaves. In fact the stems and the radiating structures of the leaf whorls is similar in the Calamites, an extinct genus of horsetails.
These horsetails were arborescent and grew to a height of 32 feet (10 meters) in a tree-like form.
Annularia leaves are arranged in whorls of between 8-13 leaves. Its shape is quite variable, being oval in Annularia sphenophylloides and between linear and lanceolate in Annularia radiata, but they are always flat and of varying lengths. This specimen has fossilized calamities branch stems on the back.