Source : Webster's Revised Unabridged Dictionary (1913)

Petitionary \Pe*ti"tion*a*ry\, a.
   1. Supplicatory; making a petition.

            Pardon Rome, and any petitionary countrymen. --Shak.

   2. Containing a petition; of the nature of a petition; as, a
      petitionary epistle. --Swift.

Source : WordNet®

petitionary
     adj : of the nature of or expressing a petition; "the petitionary
           procedure had a quality of indecisiveness"