Irish people are being asked to report where mistletoe, the most romantic of Christmas plants, is growing in this country as part of a national survey on the shrub.
Mistletoe is known to be growing in counties Waterford, Wexford, Carlow, Limerick, Wicklow, Dublin, Armagh, Down and Antrim, according to Dr Charles Nelson, who is carrying out the work.
"It is not a native plant but was introduced into Ireland in the middle of the 19th century," said Dr Nelson.
"If there is a hot-spot for mistletoe, it is Glasnevin in Dublin, close to where it was first grown in Ireland.
"Since the survey started, I now know that it is growing in Palmerston Park, Mount Usher, Bunclody, Birr, Adare and Waterford.
"It is hard to grow and I suspect it was cultivated by gardeners in the bigger demesnes around the country.
"However, it can be spread by birds and it seems to grow best on apple trees, though there are few references to it in Armagh and Kilkenny, which have the highest concentrations of orchards."
However, he said in Ireland mistletoe has been found on Norway maple, sycamore, red horse chestnut, cotoneaster, cultivated and crab apples, willows, rowan, lime and poplars, but not on oak.
"The myth that Irish druids went around cutting mistletoe with golden sickles would appear to be without logic I am afraid."
Dr Nelson said he was hoping that birdwatchers would keep an eye out for the plant because it frequently grows high in the branches of tall trees such as poplars and limes.
"The problem with botanists is that they keep their heads down whereas birdwatchers keep looking up."
Dr Nelson said he did not know where the association with kissing and mistletoe came from but he imagined it was part of pan-European culture.
• Dr Nelson can be contacted at Tippitiwitchet Cottage, Hall Road, Outwell, Wisbech, Cambridgeshire PE14 8PE, or e-mail: tippitiwitchet@zetnet.co.uk.