Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class carbohydrates [Cn(H2O)n, etc.]
                 Class saccharides
                   Class monosaccharides - sugars
                     Class aldoses [H[CH(OH)]nC(=O)H (n>=2), etc.]
                       xylose [C5H10O5; CH(=O)[CHOH]3CH2OH]