katuchka's Identifications

The Polypodiidae, also known as leptosporangiate ferns, formerly Leptosporangiatae, are one of four fern subclasses, and the largest of these, comprising approximately 11,000 species worldwide. Although other classifications assign them a different rank, t he group has also been treated as the class Pteridopsida or Polypodiopsida. Filicidae and Filicales were older names for the group, though the "water ferns" (now the Salviniales) were treated separately at the time. These ferns are known as leptosporangiate because their sporangia form from a single epidermal cell rather than a group of cells as in eusporangiate ferns (a polyphyletic lineage). The sporangia are typically covered with an indusium scale, which can cover the entire sorus, forming a ring or cup around the sorus.