The UK's space agency is hunting for 'moon trees' grown from seeds that went on the Apollo 14 lunar mission

A sycamore moon tree planted at Mississippi State University in 1975. It grew from a seed that traveled to the moon and back during the Apollo 14 lunar mission.

(CNN)Fifty years ago, NASA's Apollo 14 completed the third crewed mission to the moon. On board the spacecraft as it landed in the Pacific Ocean on February 9, 1971, was some unusual cargo -- about 500 tree seeds.

The seeds -- loblolly pine, sycamore, sweetgum, redwood and Douglas fir -- had traveled with Stuart Roosa, one of the three NASA astronauts on the mission and a former US Forest Service parachute firefighter, sealed in small plastic pouches stored in a metal canister in his personal luggage. They were part of an experiment to see how seeds reacted to the space environment.
Upon their return to Earth, the seeds were germinated by the Forest Service. Known as the "Moon Trees," the resulting seedlings were planted throughout the United States and the world, according to NASA. There was no systematic effort to keep track of them, but NASA has since tracked down about 60 trees -- mainly in the US but also ones in Brazil, Japan and Switzerland.
    Steve Miller, vice president of the Royal Astronomical Society and a professor at University College London, believes that some of these seeds or seedlings ended up in the United Kingdom. He wants to know what happened to them, as does the UK Space Agency.
      His quest began after he asked a popular BBC radio show "Gardener's Question Time" about a suitable horticultural way to mark the Royal Astronomical Society bicentenary, celebrated in 2020.
      Panelist and gardener Christine Walkden suggested he look for the trees grown from the moon seeds that she believed were planted in the UK and get a cutting from one of them. However, no evidence has been found that they exist in the UK.
      Two potential recipients, Kew Gardens in London and the arboretum at Jodrell Bank, the UK's main space observatory, have no records of the seeds that supposedly came to the UK, Miller said.
        He's now appealing to the public for any leads.
        In the United States, many of the seeds were given away to state forestry organizations in 1975 and 1976 to be planted as part of the country's bicentennial celebrations. According to NASA, a loblolly pine was planted at the White House. Trees have also been planted in Washington Square in Philadelphia, in the International Forest of Friendship at Valley Forge, and at various universities and NASA centers.
        Miller has been able to track down a "half moon tree" created from a cutting taken from one of the moon trees that was planted in the United States. The half moon tree is growing in a private garden in the village of Flamstead in the Chiltern Hills to the north of London. The RAS has been promised a cutting from that tree for its bicentenary.
        Apollo 14 astronauts pose for a group portrait at a prelaunch news conference at Kennedy Space Center in Cape Canaveral, Florida. From left to right: Edgar J Mitchell, Alan B Shepard and Stuart A Roosa.