[2] This family is composed of gymnosperms, and because of their stem structure discovered through fossil rocks, they are considered to be in this division.

[6] However, nothing is known of their reproductive organs, but they are classified as seed plants based on their similarities to the Lyginopteridaceae and Medullasaceae families within Pteriodspermatophyta.

[4][5] To identify a genus within this family, this petiole structure and monoxylic wood must be present, as well as a much larger cortex than vascular cylinder.

[1] Calamopityaceae fossils have been found in North America and Europe, and they have been dated back to the Paleozoic era, specifically the Upper Devonian and Lower Carboniferous (Mississippian) periods.

[4][5] In 1856, the Austrian paleontologist, Franz Joseph Andreas Nicolaus Unger, was the first to find Calamopitys, a genus of Calamopityaceae.

Though the original genera, Calamopitys, Stenomyelon, and Diichnia, still remain under this family classification, there have been historical additions to these groupings.

[11] Three genera of fossil wood are currently classified as belonging to the family Calamopityaceae, and their differences are distinguished by their decreasing primary xylem from Stenomyelon, to Calamopitys, to Diichnia.

[6] Although Eristophyton is sometimes considered to be a subgenus under this genus, the distinction between pycnoxylic and monoxylic secondary wood maintains these genera as separate.

[6] In terms of structure, these plants under this genera have narrow stems with diameter 2–3 cm (or larger in C. embergeri and C.