Where the plant quarantine inspector requires the entire shipment to be returned to the country of origin as a prohibited importation (in which event he shall endorse his action thereon) and delivers the shipment to the collector of customs, the collector shall in turn deliver it to the postmaster for dispatch to the country of origin. If, upon examination, the plant material is deemed dangerous to plant life, the collector of customs shall permit the plant quarantine inspector to destroy immediately both the container and its contents. In either case the plant quarantine inspector shall notify the addressee of the action taken and the reason therefor. If the objectionable plant material forms only a portion of the contents of the mail package and in the judgment of the inspector the package can safely be delivered to the addressee, after removing and destroying the objectionable material, such procedure is authorized. In the latter case the inspector shall place in the package a memorandum (Form AQI-387) informing the addressee of the action taken by the inspector and describing the matter which has been seized and destroyed and the reasons therefor.