Mo. Rev. Stat. § 171.011: School board may adopt rules and regulations.

The school board of each school district in the state may make all needful rules and regulations for the organization, grading and government in the school district. The rules shall take effect when a copy of the rules, duly signed by order of the board, is deposited with the district clerk. The district clerk shall transmit forthwith a copy of the rules to the teachers employed in the schools. The rules may be amended or repealed in like manner.