Mo. Rev. Stat. § 528.080 – Those having an interest may appear and be made parties

Any person having an interest in such premises, whether the same be present or future, vested or contingent, though not made a party in the petition, may appear and be made a party on application for that purpose, accompanied by an affidavit of such interest.

(RSMo 1939 § 1716)

Prior revisions: 1929 § 1552; 1919 § 2000; 1909 § 2564