[plants] Haeckel (1866) - plants
   vascular plants see Phylum Tracheophyta Sinnott ex Caval.-Sm. (1998)
     euphyllophytes see Clade Euphyllophyta Lecointre & Le Guyader 2006 [Cantino & Donoghue 2020]
       "Moniliformopses" Kenrick & P.R.Crane (1997), nom. inval. - ferns see Infraphylum Moniliformopses Kenrick & P.R.Crane (1997), nom. inval.
         Class Polypodiopsida Cronquist, Takht. & Zimmerm. (1966) - ferns
           Order Salviniales Link (1833) - water ferns
             Family Salviniaceae Martinov (1820) - floating ferns
               Genus Azolla Lam. (1783)