A potato plant collected by Charles Darwin during his voyage on the Beagle is among botanical treasures to go on display to the public for the first time.
The specimen was re-discovered in a cabinet in the herbarium of the Royal Horticultural Society five years ago.
The famous naturalist came across the plant on an island off Chile in 1835.
"It's part of the history of science," says Tivvy Harvey, keeper of the herbarium.
"It was part of the voyage and the voyage led to the theory of evolution."