Preliminary report on permineralized Senftenbergia from the Chester Series of Illinois

Specimens of Senftenbergia from the Chester Series of Illinois include ones having both external features diagnostic of the genus, and internal anatomy. The anatomy of the frond does not support the generally held view that Senftenbergia is related at the family level to the modern schizaeaceous ferns. Both the form of the vascular system and the presence of peripheral loops are characters that the genus shares with the coenopterid ferns Ankyropteris and Clepsydropsis, but are unlike any of the Schizaeaceae.