Pecopteris Falcatus Emmons Fern, from Tarahumara, Senora State, Mexico (REF:PFEF419)

Pecopteris is a very common form genus of leaves. Most Pecopteris leaves and fronds are associated with the marattialean tree fern Psaronius. However, Pecopteris-type foliage also is borne on several filicalean ferns, and at least one seed fern.

Pecopteris first appeared in the Devonian period, but flourished in the Carboniferous, especially the Pennsylvanian subperiod (323.9-298.9 Million Years Ago). Plants bearing these leaves became extinct in the Permian period, due to swamps disappearing and temperatures on Earth dropping.