Carboniferous (Westphalian)
Mudstone Series
Upper Silesia, Poland
Big 30mm fruiting body from a seed fern.

Cone, Fern. Fructification.

Whittleseya is a genus of seed fern in the plant order, Medullosales.  It appeared in the Carboniferous and survived into the Triassic Period.  The order died out by the end of the Triassic.  Their closest living relatives are cycads.