Revision of the Pennsylvanian fern Boweria Kidston and the establishment of the new genus Kidstoniopteris

Boweria is a fossil-genus of Pennsylvanian true ferns whose exact taxonomic position was for many years confused. The morphology of reproductive structures (including sporangia), pinnae, pinnules and in situ spores (Leiotriletes and Granulatisporites types) of the type species (Boweria schatzlarensis) are described in detail. A new species (Boweria nowarudensis) is distinguished by its sporangia being isolated with two types of cells and a lateral annulus, and containing microspores of the Granulatisporites minutus type. Another former species of the genus (Boweria minor) is transferred to a new genus (Kidstoniopteris minor) based its irregularly grouped free sporangia with three types of cells, and in situ microspores of the Granulatisporites type, and laevigate spores of the Leiotriletes type.