Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         "crystal-kingdom"
           chemical substances
             chemical compounds
               Class isoprenoids
                 Class terpenes
                   1 Class hemiterpenes [C5 skeleton] - terpenes having one isoprene unit
                   2 Class monoterpenes [C10 skeleton] - terpenes having two isoprene units
                   3 Class sesquiterpenes [C15 skeleton] - terpenes having three isoprene units
                   4 Class diterpenes [C20 skeleton] - terpenes having four isoprene units
                   5 Class sesterterpenes [C25 skeleton] - terpenes having five isoprene units
                   6 Class triterpenes [C30 skeleton] - terpenes having six isoprene units
                   7 Class tetraterpenes [C40 skeleton] - terpenes having eight isoprene units
                   8 Class polyterpenes [C5n skeleton] - terpenes having more than eight isoprene units