Group Pteridospermae, more commonly known as seed ferns, is a diverse and complex group of plants that existed during the Carboniferous and Permian periods. This group is characterized by their fern-like fronds, which held seeds instead of spores, making them similar to modern day gymnosperms. There are several synonyms that have been used to describe this group of plants, including "Pteridospermopsida", "Pteridospermatophyta", and "Pteridospermophyta". While the exact classification of seed ferns remains debated among scientists, there is no doubt that these fossils provide important insights into the evolution of plants and the history of the earth.