Very Rare Sphenopteris preslesensis extinct pre dinosaur fossil plant fern leaf

Description

My specimens are genuine and will be delivered with a "Certificate of authenticity, age and origin"  and scientific paper allowing plant identification !
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Specimen:
Very rare, extinct primitive leaves fossil fern species:
Sphenopteris
preslesensis
STOCKMAN &WILLIERE
Locality:
All detailed and accurate data will be provided with the specimen
Stratigraphy:
Upper Carboniferous, Middle Pennsylvanian, Namurian B
Age:
ca. 320 Mya
Nodule dimensions:
ca 11,5 x 8,0 x 2,5 cm ( white square on pictures is 1,0 x 1,0 cm  )
Description:
Very rare, extinct , namurian B age coal age
herbaceous fossil fern
-
Sphenopteris
preslesensis
STOCKMAN &WILLIERE
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.
Systematic:
Ordo:
Medullosales
Familia:
Whitleseyinae
Genus:
Alethopteris
Species:
Sphenopteris
preslesensis
STOCKMAN &WILLIERE