More than 200 years after her death the MacDonald story - and the mythology that has grown up around the reality - continues to grip the imagination across the world.

Attend any clan gathering and you will find dozens of earnest descendants of Highlanders who honestly claim the heroine to be an ancestor. But is it possible that so many could be part of the same family?

At least eight generations have passed since the Jacobite helper lived but expert genealogists are certain that Flora has hundreds of descendants. What's difficult to determine, however, is who among the thousands are truly linked to her.

Records show Flora and her husband Allan MacDonald of Kingsburgh had seven children. Their lives were as turbulent as the times they lived in and many of her children were to die young.

Reginald Henry MacDonald, the XVth of Kingsburgh and Castle Camus, in 1961 prepared a family tree to trace Allan and Flora MacDonald's descendants. Two of Reginald’s grandchildren live Stateside, and Clan Donald USA believe they are the only two known descendants in America.

"It is improbable that so many could be the direct descendant of Flora MacDonald. In fact I know of only two in the USA," says Mark MacDonald, national historian for Clan Donald USA.

To complicate matters, many people come from the female line of the family and about three-quarters of her descendants will not have the MacDonald name. Flora's sister-in-law Anne, for example, had 14 children and at least one of Anne's daughters had 16 children, and members have lived in New Zealand, South Africa, as well as the UK and US.

"In general, without impugning the assertions of those [whose claims I have not verified], it is quite common for people in the US, and Canadians who later emigrated to the US, to mistakenly assert Flora descent because it is a romantic line and their grandparents may have been the source of the inaccurate information," says MacDonald.

Clan Donald USA has a regular presence at gatherings and Highland games in the US, where their tent is a magnet for Americans of Scottish origins in search of their roots. MacDonald adds: "About 5 per cent of the people we get through our doors believe they are descended from Flora. We politely listen … and attempt to gently redirect them toward more accurate alternatives for their genealogies."

Flora's time in America is well documented, and she gave her own breathtaking account of the time in her own handwriting. She spent five years in America from 1774, when she and her husband set sail for North Carolina with two of their sons, Alexander and James. Her daughter Anne, along with her husband Alexander MacLeod and their two sons, also made the six-week journey. Flora's other children - Ranald, a Marine, Charles, who worked for the East India Company, John, 15, a student in Edinburgh, and Fanny, eight - remained in Scotland.

The MacDonalds arrived in the New World just as the American Revolution was intensifying and, like many Highlanders, Flora and her family sided with the Crown. Allan and Alexander were captured by Revolutionary troops along with Alexander MacDonald of Cuildreach, the husband of Flora's sister, Annabella. The family plantation was said to have been confiscated after Flora refused to take the oath of allegiance to North Carolina.

On her arrival in London in 1779 she learned of the death of her son, Alexander, at sea. Two years later her son, Ranald, also died at sea.

She wrote in her account: "To my great sorrow, on my landing, received the melancholy news of my son Alexander's death … and a short time thereafter got the account of [the ship] Villa de Paris being lost on her way home, where my beloved son Ranald was captain of the marines…

"Those melancholy strocks, by the death of my children who, had they lived, with God's assistance, might now be my support in my declined old age…"

Flora was, however, reunited with two of her children, Anne MacLeod, and Fanny, her youngest, whom she had not seen since she had left five years before.

Allan and Flora MacDonald, their surviving sons, Charles and James, and their daughters, Anne and Fanny, all returned home to Skye with stories and memories of exciting experiences. Flora died in 1790 and Allan two years later, both buried on the island.

Hugh Peskett, the genealogist who traced former US president Ronald Reagan's Scottish and Irish roots, said one explanation for the high levels of Americans believing they are descendants of Flora MacDonald might be down to a case of mistaken identity.

Pestkett, who is the Scotland editor for Burke's Peerage, the British and Irish genealogy specialists, said: "Flora was and still is a popular name in the West Highlands. There may be families who are MacDonalds, but not necessarily the MacDonalds of Kingsburgh. But there is a Flora in every generation and so it enters family tradition. I am afraid that most of these probably will not stand scrutiny of the records. Some, of course, will be related to Flora MacDonald as she will have hundreds of descendants."

While most of MacDonald's children were in Britain at the time of her death, Peskett says there is every possibility that subsequent generations may have moved to America. He says: "Flora’s life illustrates an important point about the movement of Highlanders to the New World. It was not 'one way'. Many came back and for some families generations have crossed the Atlantic both ways."

Charles Mosley, editor in chief of Debrett's, the genealogy experts, said: "There is a good chance that she will have hundreds, if not thousands of descendants, even if she only had two children. She lived 250 years ago and that means there have been about eight generations since, and that makes a lot of descendants.

"I wouldn't dismiss out of hand those who claim ancestry on the basis of the oral history of the family either. While records in America are intact from colonial days, many records in Europe are incomplete, due to wars and other such disturbances," Mosley says.