Cal. MVC § 550

Whenever any part of the National Guard of this state is in active federal service, or when Congress consents thereto, the Governor may organize and maintain within this state during that period, under regulations the Secretary of Defense of the United States may prescribe for discipline in training, the military forces the Governor deems necessary to defend and for the security of this state; provided, however, the Governor may authorize the organization and maintenance of these forces at cadre strength at any time. These forces shall be composed of officers commissioned or assigned, and the qualified citizens or persons who are not citizens or nationals of the United States who have declared their intentions to become citizens and who volunteer for service, supplemented, if necessary, by members of the unorganized militia enrolled by draft or otherwise as provided by law. These forces shall be additional to and distinct from the National Guard and shall be known as the State Guard. These forces shall be uniformed under the conditions and subject to the regulations as the Governor may prescribe.