Matoniaceous ferns preserved in growth position in Lower Jurassic dune sandstones of the Holy Cross Mountains (Poland)

The occurrence of the fern Matonia braunii (Goeppert) Harris, preserved in the growth position in sandstones of dune origin, is documented from the late Pliensbachian Szydłowiec Sandstone of the Drzewica Formation in the Holy Cross Mountains. This plant formed monotypic stands on coastal dunes during a marine highstand. The presence of this common Early Jurassic fern in such an unfavourable environment attests to the huge ecological plasticity of this species.