The “Burbank” complaint challenges this assertion on the basis that
The Smithsonian Institution is an instrumentality of the United States, chartered by the Congress, and the recipient of $745.8 million dollars in federal appropriations in FY 2009. The Smithsonian Institution receives use of some of the most valuable real estate in the country. The Smithsonian Institution is not allowed to claim copyright in ownership in items unless it falls under specific exemptions, such as a specific requirement by a donor that copyright be maintained on specific items.
The US copyright law provides that copyright protection is not available for any work of the US government.
Luther Burbank, as you will likely know, was an American pioneer in agricultural science who demonstrated in his work the power of creativity. The reference to him here is meant to draw attention to the aims of copyright law and, indeed, the Smithsonian, to spur and support invention and creativity.