Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       particles
         hadrons - composite particles
           baryons - fermionic hadrons
             Xi baryons - baryons with one u or d quark (I=1/2)
               1.1 Xi0 - neutral Xi
               1.2 Xi- - negative Xi
               2.1 Xi(1530)0
               2.2 Xi(1530)-
               3.1 Xi(1690)0
               3.2 Xi(1690)-
               4.1 Xi(1820)0
               4.2 Xi(1820)-
               5.1 Xi(1950)0
               5.2 Xi(1950)-
               6.1 Xi(2030)0
               6.2 Xi(2030)-