A search for geriatric buttercups is under way to enable scientists to work out the age of Britain’s meadows.

Buttercups are thought to be able to survive, like some grasses, for hundreds of years and perhaps more than a thousand. By identifying the presence and spread of buttercups in a meadow, researchers hope that it will be possible to date them just as rings in trunks give the age of trees. Dr John Warren, of Aberystwyth University, aims to find Britain’s oldest meadow. He wants the public to help by sending reports of creeping buttercups and the number of their petals.

One of the most common species of buttercup is goldilocks. The older it gets, the more genetic mutations it has. As it is asexual, it is unable to fix the genetic code with each generation, so they accumulate mutations. Dr Warren hopes that by identifying the number of mutations it will be possible to judge the age of the buttercups and thus the age of meadows.

Many of the mutations affect the number of petals the flower has, so that instead of having five it can muster as many as nine or as few as one. The shape of the petals can also indicate mutations. Buttercups spread across a field by growing runners which creep along the ground, set down roots and develop new leaves and flowers. The date and conclusions assembled during the project will help to improve the understanding of Britain’s biodiversity and should pinpoint the most valuable meadows that are most in need of protection from development.

“In this day and age we worry about biodiversity,” Dr Warren said. “If it takes a long time to assemble, we should value it a lot more. We can sow wild flower seeds, but if it takes 500 years to get a fully mature meadow we should be a lot more careful about keeping them.” He said that goldilocks,Ranunculus repens, was the ideal buttercup for the study: “In ordinary buttercups you can start with a fresh individual. Golidlocks is asexual, so when it develops mutations it has no means of shedding them. It’s a really odd plant. It can have just the one petal.

“It’s weird in the number of petals it can have. Preliminary research has shown that old buttercups from older pastures are more likely to have extra petals than young buttercups in newly established fields.”

The technique has similarities to the longstanding but crude method of estimating the age of a hedge by c o u n t i n g woody species along a 30-metre length and assuming 100 years for each one.

Two common species of buttercups other than the creeping variety are also readily found, but creeping buttercups can be distinguished from meadow buttercups because their leaves are in three parts and are connected by short lengths of stalk. The bulbous buttercup has “sepals” just behind the flowers and which fold back over the stem.

Members of the public willing to help the researchers at Aberystwyth are asked to find a field of buttercups and, after identifying the creeping species, count the petals of 100 flowers. An estimate of the last time the field was ploughed is useful and can often be provided by a landowner or local historian. Details should be e-mailed to Dr Warren at jhw@aber.ac.uk.

Times recommends

• Energy-saving ideas from switched-on professor
• Rooks are as clever with tools as chimpanzees
• Burping of the lambs blows roast off menu