A petition shall include allegations of (1) the authority for and the purpose of the taking; (2) a description of each lot, parcel or tract of land and the nature of the interest to be taken; (3) insofar as their interests are to be taken (a) the name of any owner and all lienholders of record, and (b) the name of any party in possession. Such petition shall be verified by affidavit. Upon the filing of such petition the court by order shall fix the time when the same will be taken up. No defect in form which does not impair substantial rights of the parties shall invalidate any proceeding.