Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       particles
         hadrons - composite particles
           baryons - fermionic hadrons
             N baryons - baryons with three u and/or d quarks (I=1/2)
               01.1 proton
               01.2 neutron J. Chadwick, 1932
               02.1 N(1440)+
               02.2 N(1440)0
               03.1 N(1520)+
               03.2 N(1520)0
               04.1 N(1535)+
               04.2 N(1535)0
               05.1 N(1650)+
               05.2 N(1650)0
               06.1 N(1675)+
               06.2 N(1675)0
               07.1 N(1680)+
               07.2 N(1680)0
               08.1 N(1700)+
               08.2 N(1700)0
               09.1 N(1710)+
               09.2 N(1710)0
               10.1 N(1720)+
               10.2 N(1720)0
               11.1 N(2190)+
               11.2 N(2190)0
               12.1 N(2220)+
               12.2 N(2220)0
               13.1 N(2250)+
               13.2 N(2250)0
               14.1 N(2600)+
               14.2 N(2600)0