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. Plants bearing these leaves went extinct in the
Permian period.