Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class hydrazonic acids [RkE(=O)l(OH)m (l≠0; ≥1 (=O):=(=NNR2))]
                 1 Class carbohydrazonic acids [RC(=NNH2)OH]
                 2 Class sulfonohydrazonic acids [RS(=O)(=NNH2)OH]