California Constitution § 9

A statute shall embrace but one subject, which shall be expressed in its title. If a statute embraces a subject not expressed in its title, only the part not expressed is void. A statute may not be amended by reference to its title. A section of a statute may not be amended unless the section is re-enacted as amended.

(Sec. 9 added Nov. 8, 1966, by Prop. 1-a. Res.Ch. 139, 1966 1st Ex. Sess.)