Mo. Rev. Stat. § 60.341: Fractional sections, how established.

In subdividing a fractional section or quarter-section, the land surveyor will run his lines from properly established quarter-section or quarter-quarter-section corners, as the case may be, with courses governed by the conditions represented upon the official government plat, to the lake, watercourse, grant boundary, state line or other irregular boundary which renders such land fractional.