Charmonium phenomenology andL=0trigluonia

Several charmonium decays which cannot be understood in a perturbative QCD scheme are considered and the possible role of glueballs in these decays is studied. In particular the decays of the ${\eta }_c$ in two vector mesons and in $p\overline{p}$ might receive a strong contribution from a trigluon $0^{-+}$ state with a mass close to that of the ${\eta }_c$. Experimental data on the decays of the ${\eta }_c^{\prime }$ could confirm the existence of such a state.