Cal. Pub. Resources Code § 9027
"Landowner" or "owner of land" includes a holder of evidence of title and, also, a holder of land under a possessory right acquired by entry or purchase from the United States or the State of California. A guardian, executor, administrator, or other person holding property in a trust capacity under an appointment of court is the "owner" of such property for the purposes of this division and as such may do and perform any act provided for herein when authorized by an order of court which order may be made without notice.
If any land is assessed on the assessment roll to unknown or fictitiously named owners, or to unnamed owners in addition to any owner or owners named thereon, the land has, for the purposes of this division, but one owner in addition to any owner or owners whose true name or names may be purported to be given on the assessment book.
The holder of title to an undivided interest in any land is an owner as to his interest for the purposes of this division, and such undivided interests shall be counted and valued as though they were separate interests. If the assessment roll fails to indicate the extent of any undivided interest, the holders of title whose undivided interests are not specifically defined are owners for the purposes of this division, of equal shares therein.
The value of any land and the owners of any land are conclusively determined, for the purposes of this division, by the last equalized assessment roll.
Ca. Pub. Res. Code § 9027