Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         ["vegetable kingdom"]
           ["Cryptogams"]
             [Class Acrogens Lindl.]
               1 [Alliance Characeales Berk. (1857)]
               2 [Alliance Muscales Lindl.]
               3 [Alliance Filicales Dumort.]