Mo. Rev. Stat. § 21.010

The general assembly shall meet on the first Wednesday after the first Monday in January in the year 1971, and on the corresponding day in January every year thereafter; and at twelve o'clock of the day fixed by law for the convening of the legislature in odd-numbered years, the secretary of state, or, in case of his death, absence or inability to act, some other person designated by the governor shall call the house of representatives together and preside over its deliberations until a temporary organization is effected.