California Code, Civil Code - CIV § 880.240

(a) The interest of a person in possession (including use or occupancy) of real property and the interest of a person under whom a person in possession claims, to the extent the possession would have been revealed by reasonable inspection or inquiry.

(b) An interest of the United States or pursuant to federal law in real property that is not subjected by federal law to the recording requirements of the state and that has not terminated under federal law.

(c) An interest of the state or a local public entity in real property.

(d) A conservation easement pursuant to Chapter 4 (commencing with Section 815) of Title 2.