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