Cal. Civ. Proc. Code § 458

In pleading the Statute of Limitations it is not necessary to state the facts showing the defense, but it may be stated generally that the cause of action is barred by the provisions of Section ____ (giving the number of the section and subdivision thereof, if it is so divided, relied upon) of The Code of Civil Procedure; and if such allegation be controverted, the party pleading must establish, on the trial, the facts showing that the cause of action is so barred.