A rescue operation is under way to keep alive a century-old plant collection, including species that exist nowhere else in the world, after the heating broke in an Edinburgh glasshouse.
The boiler heating research glasshouses at the Royal Botanic Garden Edinburgh has failed.
The glasshouses, which cover 4,000 sq ft and house 3,000 species, need to be at a temperature between 22C and 24C.
Now dozens of temporary heaters have been brought in to keep them alive.
Engineers said they will have the heating system fixed by Monday. By then, the plants will have gone 10 days without the normal heating system.
Although the temporary heaters are only managing to keep the glasshouses at a temperature between 12C and 14C, experts at the site said they were hopeful they could keep the plants alive until the heating system was fixed.
One of the species in the glasshouse is a pelargonium insularis from the Samhah Island in the Socotra archipelago of Yemen. It was discovered in 1999 and propagated from a single plant. It is now believed to be extinct in the wild.
Simon Milne, Regius Keeper at the Royal Botanic Garden, told the BBC Scotland news website of his "worry and concern" because the plant collection was their most valuable asset.
He said: "This is a century of exploration and collecting which form much of our international research. There are species that are new to science in these glasshouses including some begonias and gingers and others that exist nowhere else in the world.
"We have an ageing boiler system and the main feed pipe, which is 40 years old, has broken under a wall. Thankfully we are not having zero temperatures outside and after commandeering heaters from around the country we are managing to keep the temperature between 12C and 14C.
"This means the plants won't prosper as its not their optimum temperature but they will hopefully survive for a few days until engineers have fixed the heating system.
"This has never happened to us before and is a result of ageing infrastructure.
"It is thanks to my amazing staff working around the clock that hopefully these plants won't suffer."