Mo. Rev. Stat. § 10.100
10.100 State tree nut — black walnut.
10.100. State tree nut — black walnut. — The nut produced by the black walnut tree ( Juglans nigra ) known as the "Eastern Black Walnut", is selected for and shall be known as the official tree nut of the state of Missouri.
(L. 1990 S.B. 749)