Cal. Civ. Code § 4910

4910.    (a) The board shall not take action on any item of business outside of a board meeting. (b) (1) Notwithstanding Section 7211 of the Corporations Code, the board shall not conduct a meeting via a series of electronic transmissions, including, but not limited to, electronic mail, except as specified in paragraph (2). (2) Electronic transmissions may be used as a method of conducting an emergency board meeting if all directors, individually or collectively, consent in writing to that action, and if the written consent or consents are filed with the minutes of the board meeting. These written consents may be transmitted electronically.