Section 31
SEC. 31. Action when owner makes no return, or is unknown, or in doubt, or when land and improvements are separately owned.—If the owner of any parcel of real estate shall fail to make a return thereof, or if the city assessor is unable to discover the owner of any real estate, he shall nevertheless list the same for taxation, and charge the tax against the true owner, if known, and if unknown then as against an unknown owner. In case of doubt or dispute as to ownership of real estate, the taxes shall be levied against the possessor or possessors thereof. When it shall appear that there are separate owners of the land and the improvements thereon, a separate assessment of the property of each shall be made.