British scientists have successfully revived mosses that have been frozen under the Antarctic ice for 1,500 years.
The researchers thawed out the ancient vegetation and were surprised to see new shoots rapidly appear.
While bacteria of a similar age have been recovered before, the scientists say these are the oldest plants to be brought back to life.
The research has been published in the journal Current Biology.
Mossy banks are a curious feature of the frozen Antarctic, formed over thousands of years from the accumulation of these tenacious plants that spring to life in the brief southern summer.
The shoots are alive right the way through the moss bank'
End Quote Prof Peter Convey British Antarctic Survey
The oldest banks date back over 5,000 years and are a useful archive for scientists of past climatic conditions.
Researchers have made previous attempts to revive long-frozen moss, but they have only managed to grow material that had been locked in ice for about 20 years.
Shoots of recovery
Now scientists from the British Antarctic Survey (BAS) and the University of Reading have taken sliced and seemingly dead samples from the deep permafrost and brought them back to life.
They were placed in an incubator at 17C, a temperature often found in Antarctic moss plants in summer.
After three weeks, new shoots appeared.
'Various people have asked us did we do anything complicated to make it re-grow,' co-author Prof Peter Convey, from BAS, told BBC News.
'We've basically just cut it in half and put in the incubator and did as little as possible.'
While the researchers did little to the plants, they took great care to ensure that there was no contamination from other life forms. Carbon dating put the age of the newly growing material at 1,530 years.
'The shoots are alive right the way through the moss bank,' said Prof Convey.
'The blue sky result is that we've really stuck a much older age on recovery than anyone has done so far.'
In both the Arctic and Antarctic, mosses are an important part of the ecosystem.
They play a major role in storing carbon and in the Arctic particularly, there are concerns that as the world warms the permafrost will emit even more CO2 into the atmosphere.
But could the discovery that moss in the southern ice can be revived after 1,500 years mean that carbon release is less of a worry?
Not quite, says Prof Convey. He says that most of the moss frozen in the Arctic is already dead and can't be revitalised. Warming there would see that carbon seep back into the atmosphere.
In the Antarctic though, it might be a different story.
'In a warmer wetter world, mosses actually grow quite well. The question is how much are these thawing mosses going to grow in response to changes and how much can that been seen as a carbon sink?'
The researchers also believe that the discovery signals that, in the right circumstances, multi-cellular organisms such as plants can survive for longer timescales than previously thought.
'My gut feeling is that if you looked at a range of plants that have these sort of tactics, in the right conditions you'd start detecting these things back longer for a number of organisms,' said Prof Convey.
Follow Matt on Twitter @mattmcgrathbbc.