Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       particles
         hadrons - composite particles
           mesons - bosonic hadrons
             c cbar mesons
               ["chi(c2)(2P)" [unconfirmed]]
               ?["X(3930)" [unconfirmed]] see chi(c2)(2P) [unconfirmed]
               ?["X(3940)" [unconfirmed]]
               ?["X(3945)" [unconfirmed]]
               ?["X(4360)" [unconfirmed]]
               ?["X+(4330)" [unconfirmed]]
               01 eta(c)(1S)
               02 J/psi(1S)
               03 chi(c0)(1P)
               04 chi(c1)(1P)
               05 h(c)(1P)
               06 chi(c2)(1P)
               07 eta(c)(2S)
               08 psi(2S)
               09 psi(3770)
               10 ?X(3872)
               10.2 ?[X(3872)+ [hypothetical]]
               11 psi(4040)
               12 psi(4160)
               13 X(4260)
               14 psi(4415)