The Late Carboniferous tropical swamp forests predominately contained spore-producing plants like the club-mosses, horsetails and ferns. There were also, however, some seed plants, in the higher less boggy areas. Most notable were the seed ferns (or the Pteridospermatophyta, that, like their close relatives, the cycads, did not reproduce very frequently, but when they did, it was by means of large seeds. The outer parts of these seeds consisted of soft tissue, which is usually not fossilized. The inner part of the seed was much harder, facilitating fossilization.

The extant descendents of the extinct Pteridospermatophyta practice sex with spores, Fossil fern fruits have also been called "petrified pecan nuts" because of their superficial resemblance to modern pecans. The plant fossil plate also contains two species of genus Neuropteris, one of which was the likely source of the fruit.