We examine the canonical forms of Painleve equations and argue that the equ
ation for Pm in which one parameter is taken to be equal to zero should be
considered as a canonical form different from the standard P-III Our argume
nt is based on the fact that the value of this parameter cannot be modified
through auto-Backlund transformations. We investigate the possible discret
e forms of this equation and produce two of them. One is of a difference ty
pe, where the independent variable enters linearly, while the second one is
of q type where the independent variable enters in a multiplicative way. T
he properties of these discrete equations are also studied.