The whole number of votes cast for Governor at the general election next preceding the filing of an initiative or referendum petition shall be the basis on which the number of signatures to such petition shall be computed. The veto power of the Governor shall not extend to measures initiated by or referred to the people. A measure initiated shall become a law or part of the Constitution, as the case may be, when a majority of the votes cast thereon, and not less than thirty-five per cent of the total vote cast at the election at which the same was submitted, are cast in favor thereof, and shall take effect upon proclamation by the Governor which shall be made within ten days after the official canvass of such votes. The vote upon initiative and referendum measures shall be returned and canvassed in the manner prescribed for the canvass of votes for president. The method of submitting and adopting amendments to the Constitution provided by this section shall be supplementary to the method prescribed in the article of this Constitution, entitled, "Amendments" and the latter shall in no case be construed to conflict herewith. The provisions with respect to the initiative and referendum shall be self-executing, but legislation may be enacted to facilitate their operation. All propositions submitted in pursuance hereof shall be submitted in a non-partisan manner and without any indication or suggestion on the ballot that they have been approved or endorsed by any political party or organization. Only the title or proper descriptive words of measures shall be printed on the ballot and when two or more measures have the same title they shall be numbered consecutively in the order of filing with the Secretary of State and the number shall be followed by the name of the first petitioner on the corresponding petition.