Fossil Fern | Alethopteris grandini | Kansas

Specimen measures approx. 4" x 1.5"

Matrix measures approx. 8.5" x 6.5" x 3"

This spectacular fern specimen is very detailed and the preservation is impeccable.

Alethopteris grandini is a classic and widely recognizable Pennsylvanian-age seed fern (Pteridosperm) commonly found in the Carboniferous coal measures of North America and Europe. Although often called a “fern,” it is technically a seed-bearing plant that simply evolved frond-like foliage.

Key Identifying Features

Frond Structure:

• Fronds are pinnate to bipinnate, forming large, elegant leaf sprays.

• Pinnae (leaflets) are attached at a slight angle along a central rachis, giving the frond a gently arched, feather-like appearance.

Leaflets (Pinnules):

• Pinnules are typically elongate-oval with a rounded outer edge and slightly tapered base.

• The midvein (primary vein) is strong and clearly visible, running straight or slightly curved toward the tip.

• Numerous lateral veins branch off the midvein at regular intervals and curve toward the leaflet margin.

Texture & Preservation:

• Surface texture can show fine venation when preserved in detail.

• Specimens are commonly preserved as carbonized impressions or compressions in shale or siltstone.