Fossil Fern | Crenulopteris acadica | Illinois

Crenulopteris acadica
Pennsylvanian
Carbondale Formation
Coal City, Illinois

Specimen approx. size: 3.125" x 0.75"

Matrix approx. size: 3.125" x 1.5"

*Note: the lighter half is much thinner than the darker half.

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.