Ferns and Seed Ferns

Restoration of a Psaronius From Morgan, 1959 in Taylor and Taylor, 1993

Ferns and seed ferns (Division Pteridophyta and Division Pteridospermophyta)

There are two types of ferns that are known from Mazon Creek. The true ferns are represented by several types, from large tree ferns to small epiphytes. Two of the common true ferns known are:

· Pecopteris, foliage
· Asterotheca, a fertile frond

Seed ferns are an extinct group, with fern-like foliage, but unlike the true ferns, their life cycle involved large seeds instead of tiny spores. They were severely reduced in their diversity at the end of the Permian period, and finally became extinct at the end of the Cretaceous. They were very common in the Pennsylvanian, and there are many types known from Illinois, including:

· Alethopteris, foliage
· Neuropteris, foliage
· Diplothmema, foliage

In some cases, we have foliage from ferns where we don't have enough information to tell whether they belong in the true ferns or the seed ferns, like these:

· Sphenopteris, foliage
· Sphenopterid, foliage