  We study a certain class of piecewise monotonic maps of interval. These maps
are strictly monotone on finite interval partition, satisfies Markov condition
and have generator property. We show that for a function from this class
distributional chaos is always present and we study its basic properties. Main
result states that distributional spectrum as well as weak spectrum is always
finite. This is a generalization of same result for continuous maps on the
interval, circle and tree. Examples showing that conditions on mentions class
can not be weakened are presented.
