The holder or holders of title, or evidence of title, and the secretary of the interior of the United States for unentered or public land, representing one-half or more of any body of lands which can be served by the irrigation system, and which, taken together, constitute one tract of land, may file with the board of directors of such district a petition in writing praying that the boundaries of such district may be so changed as to include their lands. The petition shall describe the boundaries of the parcel or tract of land, and also shall describe the boundaries of the several parcels owned by the petitioners, if they are the owners of district parcels. Such description need not be more particular than may be required when such lands are entered by the township assessor in the assessment book. Such petition must contain the assent of the petitioners to the inclusion in said district of the parcels or tracts of land described in the petition, and of which the petition alleges that they respectively are the owners, and it must be acknowledged in the manner in which a conveyance of lands is required to be acknowledged.