When any of the real property of which a decedent dies seized passes to a body politic or corporate, or to a devisee or beneficiary other than the corporations, institutions and organizations specifically exempted under chapters 33 to 36 of this title (s. 54:33-1 et seq.), from the tax thereby imposed, the heirs, devisees, executors, administrators or trustees of such decedent shall give information thereof in writing to the state tax commissioner within six months after they obtain title thereto or undertake the execution of their respective duties, or, if the fact be not known to them within that period, then within one month after the same has come to their knowledge.