CALAMITES

originally, a stem fragment of a fossil plant prominent during the coal age, the Carboniferous Period (from 286 million to 360 million years ago). As such, it was termed a form genus. Later, the connotation was broadened to include an idealized treelike plant, and it became a full genus designation. Furthermore, the term calamite is used for any member of the family to which the original Calamites was assigned; the Calamitaceae, order Calamitales, class Sphenopsida. Calamites and other treelike plants of the coal age constitute the coal that provides a source of energy today.