Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       artefacta - artefacts
         Product group materials
           Product group fibers
             Product group natural fibers
               Product group animal fibers (protein-base)
                 1 Product silk (fiber)
                 2.1 Product cashmere (fiber)
                 2.2 Product mohair (fiber)
                 2.3 Product wool (fiber)