Eusphenopteris and Neuropteris Seed Fern Fossils

Pteridosperms or seed ferns are a group of extinct plants with mostly fern-like foliage but having real seeds. They were mostly small trees but other forms that exhibited climbing growth have been found. Some forms, notably those called the Medullosales as seen here had large fronds which could be up several meters long. Several groups can be distinguished within the Pteridosperms. The Pteridosperms evolved in the latest Devonian, and became common in the Carboniferous. The Medullosales appeared in the late Mississippian where they dominated wetlands, and persisted into the early Permian before becoming extinct.

These are two different seed ferns from the same site. To the right is Neuropteris with frond segments having numerous pinnules, a seed fern genus charactrerized by rounded leaflets that are nomally blunt at the tips. To the left is Euspenopteris, a seed fern genus characterized by smallers and more delicate round-lobed leaflets. The specimens come from the Fire Creek Formation (coal country), West Viginia, and dates to the Lower Pennsylvanian.