Rare Pteridosperm or Seed Fern Fossil Fruit

Pteridosperms or seed ferns are a very heterogeneous group of extinct plants with mostly fern-like foliage but with real seeds. Their descendents today practice sex with spores, but these ancient ancestors, the seed ferns used seeds. This is Trigonocarpus, which is the "seed" or "megaspore" of the seed fern Neuropteris. This fossil fern fruit have also been called "petrified pecan nuts" because of their superficial resemblance to modern pecans.

The plant fossil plate also contains two species of the genus Neuropteris.