Michigan Compiled Laws, Chapter 450. Corporations § 450.1506

Sec. 506. (1) The articles of incorporation or a bylaw adopted by the shareholders or incorporators may provide that in lieu of annual election of all directors the directors be divided into 2 or 3 classes, each to be as nearly equal in number as possible. The term of office of directors in the first class shall expire at the first annual meeting of shareholders after their election, that of the second class shall expire at the second annual meeting after their election, and that of the third class, if any, shall expire at the third annual meeting after their election. At each annual meeting after such classification, a number of directors equal to the number of the class whose term expires at the time of the meeting shall be elected to hold office until the second succeeding annual meeting if there are 2 classes, or until the third succeeding annual meeting if there are 3 classes.

(2) A corporation having more than 1 class or series of shares may provide in its articles for election of 1 or more directors by shareholders of a class or series, to the exclusion of other shareholders.