Mo. Rev. Stat. § 90.510: Public parks, maintenance.

In case of an increase in valuation in any year of the taxable property within any city, or whenever the common council of such city is satisfied that a lower rate will produce ample funds, it may reduce the levy herein provided for by levying a tax for the maintenance of said free public parks which in the judgment of said common council shall be sufficient for the maintenance of said free public parks throughout the year.