Sphenopteris Seed Fern From Poland

This is a specimen of a seed fern Sphenopteris sp. from the Upper Carboniferous coal beds of Poland. This delicate herbaceous plants, are rarely found as a fossils.

Zeilleria, Discopterids, Uranopterids etc. were mostly a herbaceous "seeds ferns" or were creeping, vine-like plants. Seed ferns (Pteridosperms) were group of seed plants from the Carboniferous and Permian periods (about 360 to 250 million years ago). Some, such as Medullosa, grew as upright, unbranched woody trunks topped with a crown of large fernlike fronds; others, such as Mariopterids, were woody vines. All had fernlike foliage; however, they reproduced by seeds, with ovules and pollen organs attached to the fronds. Gamete - producing structures in the seeds were surrounded by a hard inner integument and a fleshy outer layer. These features have led some authorities to speculate that these seeds may have been dispersed by animals. Some seeds were large. ( Pachytesta gigantea, a seed of Medullosa, grew up to 7 cm long.) Pollen organs of seed ferns were also large and complex and were commonly made up of many pollen sacs fused into a large structure.