  It is shown that the experimental data of psi(3686) and psi(3770) are
consistent with a -90 degree phase between the strong and eletromagnetic decay
amplitudes. The e+ e- -> rho-pi measured at psi(3770) is also consistent with
the branching ratio predicted by Rosner's scenario on rho-pi puzzle in
charmonium physics. This scenario leads to a possible large charmless branching
ratio in psi(3770) decays.
