By Alex Kirby
BBC News Online environment correspondent
British conservationists are so worried about the fate of a rare plant species that they are making a tempting offer.
Juniper is an important part of the UK's culture and landscape (Image: Plantlife)
The first 50 people to join Plantlife International's survey of where juniper shrubs live in the UK's uplands will be offered a free bottle of organic gin.
Flavouring gin is just one of the many uses of the aromatic juniper, which is thought to be declining across the UK.
Plantlife says one cause is that many surviving bushes are over a century old and therefore little use for breeding.
The juniper, Juniperis communis, is one of only three native conifers in the UK; the others are the yew and the Scots pine.
It is found across most of Europe, except a few places including Crete and Sardinia, and is the only juniper species to be found in both hemispheres. It can grow on both acid and alkaline soils.
The shrub is wind-pollinated, and the birds disperse the seeds after eating the berries. The seeds take two to three years to ripen.
Many junipers are now too old to breed well (Image: Bob Gibbons/Plantlife)
The oldest specimen recorded, from Teesdale in north-east England, was at least 255 years old, but a normal lifespan on southern chalk is about 100-120 years.
Plantlife says there is evidence that juniper has declined in the UK by about 70% since the 1970s.
One problem, it says, is that many surviving bushes are too old to breed easily, and any seedlings that do result are at risk from grazing animals.
Other impediments are land use change, a lack of suitable sites poor in nutrients, fires, and development.
So Plantlife is launching a survey of upland juniper, asking people to keep a look-out for its black berries and blueish-green leaves in the Highlands, north-west Scotland, Northumberland, Cumbria and North Wales.
It says no botanical expertise is needed to complete the survey, which is available from its website, or by e-mailing email@example.com.
Apart from flavouring gin, the berries are often used in cooking game, and oil of juniper has an ancient reputation as an abortifacient, which perhaps explains another of its names, bastard's bane.
In Scotland the fragrant wood was the fuel of choice for illegal whisky stills, as it is said to burn with less smoke than other woods.