Fossil Fern | Crenulopteris acadica | Illinois

This Pennsylvanian period fossil fern, Crenulopteris acadica, is from the Carbondale Formation in Coal City, Illinois.

Specimen measures approx. 2.25" x 0.5"
Matrix measures approx. 2.25" x 1.25"

Crenulopteris acadica is an extinct seed fern (Pteridosperm) known from the Pennsylvanian (Carboniferous) period, approximately 310–315 million years old.

Morphology

• Fronds are pinnate to bipinnate, with well-defined, evenly spaced pinnae.

• Pinnules are typically rounded to ovate, attached directly to the rachis without a stalk (sessile).

• Margins commonly show the crenulated or scalloped edges that give the genus its name.

• Venation is open and regularly branched, with a strong midvein and secondary veins arching toward the pinnule margins.