California Code, Education Code - EDC § 44258

A teacher who is authorized for single subject instruction may be assigned, with his consent, to teach any subject in his authorized fields at any grade level;  preschool;  kindergarten and grades 1 to 12, inclusive;  or in classes organized primarily for adults, and similarly, a teacher authorized for multiple subject instruction may be assigned, with his consent, to teach in any self-contained classroom;  preschool;  kindergarten and grades 1 to 12, inclusive;  or in classes organized primarily for adults;  and similarly, a teacher authorized as a specialist teacher may be assigned, with his consent, to teach in his area of specialization at any grade level;  preschool;  kindergarten and grades 1 to 12, inclusive;  or in classes organized primarily for adults.