Systema naturæ - nature
   Universum - universe see [unranked] Mundus Plinius
     naturalia - natural bodies
       Regnum Animale nom. inval. - animal kingdom see Kingdom Animalia Linnaeus, 1758
         Class Aves Plinius, nom. inval. - birds see Class Aves Linnaeus, 1758
           Order Anseres nom. inval. see Order Anseres Linnaeus, 1758
             Genus Cygnus nom. inval. see Genus Anas Linnaeus, 1758
               1 Olor Plinius, nom. inval.
               2 Elder nom. inval.
               3 Anser Plinius, nom. inval.
               4 Anser Bernicla nom. inval.