Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       Astra Plinius - celestial bodies
         1 Universe
         1.0.1 [Sidera Plinius - stars]
         1.0.2 [Planetae - planets]
         1.0.2.0 [Stellae erraticae - planets] see [unranked] Planetae