Mo. Rev. Stat. § 137.165: Procedure of assessing real estate omitted from tax books.

If by any means any tract of land or town lot shall be omitted in the assessment of any year or series of years, and not put upon the assessor's book, the same, when discovered, shall be assessed by the assessor for the time being, and placed upon his book before the same is returned to the court, with all arrearages of tax which ought to have been assessed and paid in former years charged thereon.