Scientists at the Royal Botanic Garden in Edinburgh have helped create the world's first DNA barcode for plants, making it quicker and easier to identify poisonous, endangered or illegal species.

The breakthrough agreement on a standard for identification comes after four years of intensive work with an international team of 52 scientists working in ten countries.

While DNA barcoding has been used successfully to distinguish among animal species since 2003, it has been virtually impossible to get any kind of agreement for botanical barcoding until now, due mostly to the complex nature of plant genetics.

Work can now begin on creating a central DNA- barcode reference library of the world's 400,000 land plant species.

The Royal Botanic Garden contributed research on DNA-barcoding Bryophytes (liverworts, hornworts and mosses), which are found in many Scottish habitats and can be of major economic importance. The result was the discovery of formerly "hidden" species classified as "new to science".

The new technique will work on minute amounts of tissue and can be used on fragments of plant material, small seedlings, and in some cases digested or processed samples. It will be used immediately in global projects such as Tree-BOL, which aims to build the DNA barcodes database for the world's 100,000 tree species, many of which are of economic and conservation importance.

The identification process will initially be laboratory-based, although it is hoped that a hand-held device might be created in the future.

Other applications include identifying illegal trade in endangered species and identifying invasive organisms, poisonous species and fragmentary material in forensic investigations.

Potentially, the main application will be assessment of the diversity of species in the world's biodiversity hotspots where a shortage of specialist skills hampers conservation efforts.

Dr Peter Hollingsworth, head of genetics and conservation at the Royal Botanic Garden, who chaired the group, explained: "Identification is important - it is the link between a given plant and the accumulated information available for that species. It is not possible to know if a plant is common or rare, poisonous or edible, being traded legally or illegally, etc, unless it can be identified.

"Conservation prioritisation, in particular, can be impeded by a lack of knowledge of what species grow where. But identifications can be difficult: there are a large number of plant species and some look very similar."