Phylum [Tracheophyta] Sinnott ex Caval.-Sm. (1998) - vascular plants Subphylum Polypodiophytina Reveal (1996) [monotypic] Class Polypodiopsida Cronquist, Takht. & Zimmerm. (1966) - ferns Subclass Polypodiidae Cronquist, Takht. & Zimmerm. (1966) Order Hymenophyllales Link (1833) [monotypic] Family Hymenophyllaceae Mart. (1835) - filmy ferns Subfamily Hymenophylloideae Burnett [monotypic] 1 Genus Hymenophyllum Sm. (1793)