No bond by its terms shall mature in more than 50 years from its own date and in the event any authorized issue is divided into 2 or more series or divisions, the maximum maturity date hereby authorized shall be calculated from the date on the face of each bond separately, irrespective of the fact that different dates may be prescribed for the bonds of each separate series or division of any authorized issue.
N.J.S. § 32:11D-70