Leptosporangiate fern
[6] Older names for the group include Filicidae and Filicales, although at least the "water ferns" (now the Salviniales) were then treated separately.[10] Smith et al. (2006) carried out the first higher-level classification of ferns based on molecular phylogenetics.[11] Later classifications renamed the group Polypodiidae, initially as a subclass of Equisetopsida sensu lato.There has been some challenge to recent molecular studies, claiming that these provide a skewed view of the phylogenetic order because they do not take into account fossil representatives.For example, fossils assigned to the Dicksoniaceae, a member of the Cyatheales, are known from the Lower Jurassic (201 to 175 million years ago).