Au electrodeposition on C(0001) from aqueous solutions with different concentrations of AuCl3. HCl, at a constant ionic mass transport rate (j(L)) in the temperature range 275 less than or equal to T less than or equal to 313 K, results in the initial formation of nanometer-sized Au islands consisting of a central core and symmetrically distributed branches with the island fractal dimension D-t = 1.6. For all values of T, the time dependence of the Au island radius fulfills a r proportional to t(n) relationship with n = 0.25 +/- 0.05. At constant T, the density of Au islands (N-s) increases according to N-s proportional to j(L)(X) with X = 0.69 +/- 0.03. At constant j(L), the value of N-s decreases as T is increased, following an Arrhenius-type relationship. Kinetic data are consistent with a growth mechanism involving surface diffusion of Au adatoms from the island core towards branch tips. From the dependence of N-s on T at constant j(L), the activation energy for Au adatom surface diffusion results in E-a* approximate to 11 Kcal/mol. This figure is slightly smaller than E-a* approximate to 14 Kcal/mol that has been reported for Au atom surface diffusion in Cl--ion free acid solutions.