Tex. Natural Resources Code § 161.324: DEFENSES IN LAWSUITS.

After obtaining the permission of the legislature, in any action brought in the courts against the state involving the title to a tract of land to which the state has a warranty deed, the state is entitled to plead all statutes of limitations in the general laws of this state, but this shall not be considered as a limitation to any other defense the state may have.

Acts 1977, 65th Leg., p. 2672, ch. 871, art. I, Sec. 1, eff. Sept. 1, 1977.