The dephasing kinetics of the excitation in the P-870 band of Rb. sphaeroides R26 and the mutant Rb. sphaeroides (M)Y210W was measured by accumulated photon echo experiments. The photon echo signal shows an extremely fast component and a nonexponential longer decay. The fast component is attributed to electron-phonon coupling, and the Huang-Rhys factor is determined to be about S = 1.7. The longer decay components are attributed to charge transfer from the primary donor. The multiple decay components can be explained by assuming dispersive kinetics due to configurational and energetic disorder. The results are compared with those of incoherent pump-probe and hale-burning experiments.