XVI International Botanical Congess

Within the leptosporangiate ferns, the families Gleicheniaceae, Schizaeaceae and Hymenophyllaceae are considered to be among the most primitive. The oldest record for Gleicheniaceae dates from the Permian and by the Mesozoic the family was already widespread in both hemispheres. Megafossils assigned to Schizaeaceae are known from the Upper Cretaceous of North America and Germany with worldwide distribution during the Tertiary. Although many fossils have been described as belonging to these families, few have been placed in a cladistic context. The purpose of this presentation is to review the fossil record for these families, to report results of a combined (morphological and molecular) analysis. In particular the effect of including these fossils on previously known and generally accepted phylogenies will be presented.