Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class flavins [1≈NC(=O)NHC(=O)C(~2)=NC(≈3)CH=C(CH3)C(CH3)=CHC(≈3)NRC(~2)≈1]
                 riboflavin - vitamin B2