Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       Astra Plinius - celestial bodies
         Universe
           Virgo-Hydra-Centaurus Supercluster
             Virgo Supercluster
               Local Group
                 Milky Way Galaxy veter.
                   Orion Arm
                     Local Bubble
                       Local Interstellar Cloud
                         Solar System
                           Earth System
                             Earth veter.
                               "spheres" (Earth)
                                 Biosphere (Earth) - zone of life
                                   "terrestrial and freshwater ecoregions"
                                     New World
                                       Nearctic
                                         "terrestrial ecoregions" (Nearctic)
                                           Northern mixed grasslands (Nearctic)
                                             "Canada" (Northern mixed grasslands)
                                               "Saskatchewan" (Canada; Northern mixed grasslands)