Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class tetrapyrroles
                 Class chlorophylls
                   Class bacteriochlorophylls
                     1.1 bacteriochlorophyll a
                     1.2 bacteriochlorophyll b
                     1.3 bacteriochlorophyll g
                     2.1 bacteriochlorophyll c
                     2.2 bacteriochlorophyll d
                     2.3 bacteriochlorophyll e