Sandra Knapp and Steve Cafferty celebrate

The Swedish botanist Carl Linnaeus was born 300 years ago this year. The Linnean Society of London holds 14,300 specimens of plants he collected or received from friends and colleagues, and other collections of insects, animals and letters. As part of the celebrations of the Tercentenary of his birth, the Society has embarked on a large-scale programme to create a digital archive of all of these important specimens.

These collections are never lent outside London, and the digitisation will help scientists all over the world. The high quality images for the first elements of the project will be available through the Linnean Society’s website from the end of 2007.

Linnaeus’s system

The science of taxonomy is that of describing and documenting the natural world, and of discovering the relationships between different kinds of plants and animals. Today, many different sorts of data, from physical characteristics, to behaviour, to gene sequences, are being used to describe and study the identity and evolutionary relationships of organisms.

In order to maintain a standard set of names and usage, taxonomists use a system established by Linnaeus in the mid-eighteenth century, and modified and improved since. Linnaeus ‘invented’ the two-word scientific names we still use today for living things – Homo sapiens (our own scientific name), Solanum tuberosum (the potato) and Drosophila melanogaster (the fruit fly) are all names that use Linnaeus’s binomial naming convention.

Research obstacles

Linnaeus and subsequent taxonomists used specimens to show how names applied to actual plants and animals. Later generations of taxonomists established rules for naming (today the Codes of Nomenclature), among which is included the concept of a type specimen. A bit like the gold standard, the type is ‘the’ specimen designated by the person describing a new species. Other specimens are used to show variability, but the type is a fixed point to which a name is tied.

Types are very important for decisions about the identity of organisms, and are critical for those who are describing and documenting diversity. Type specimens are carefully looked after by herbaria and museums, and are sometimes lent to scientists working in other parts of the world. Some, however, are very fragile, or too historically precious to be lent, and scientists need to come to the institution where they are held to examine them. This can be prohibitively expensive, and occasionally impossible due to travel restrictions, especially for scientists from the developing world. Most of the world’s diversity lies in the developing world, while most type specimens are held in the developed world. Enter technology to the rescue!

Widening access

In recent years British institutions that hold plant collections (including the Natural History Museum, the Royal Botanical Gardens, Kew and the Royal Botanic Garden Edinburgh) have prioritized access for colleagues not only in the developing world, but also to the general public. The historically important plant specimens held by the Linnean Society (often among the oldest type specimens for widespread species) are uniquely important for science and access to them is of global interest.

An image of the type specimen will often enable a scientist to make a decision as easily as the real thing; digital imaging is revolutionizing access to scientifically important primary data. Plant specimens – as essentially 2D objects – are particularly well-suited to imaging, and if the image is high enough quality, even tiny features can be seen.

Conserving biodiversity

It may seem that the digitization of such specimens is an esoteric exercise, useful only to a few academics. These digital images, however, will be important in many ways. Conservation of biodiversity, one of the great modern challenges, depends partly on the ability to accurately identify and name species of plants and animals. Universal access to the images of type specimens will help us to stabilise naming, and to better communicate about threats.

The Global Strategy for Plant Conservation (GSPC) has as one of its targets a widely accessible working list of all known plant species. Digital access to those important specimens tied to names will help pull the botanical community together to achieve this goal.

Linnaean specimens are particularly important for conservation. Many of those species described by Linnaeus are today our most invasive weeds. Accurate identification will help identify new areas of spread of invasive species, one of the five greatest threats to biodiversity identified by the Millennium Ecosystem Assessment (MA). Digitization to improve access is important not only for these scientific and conservation goals, but also brings the treasures held in our great collections to a wider public, as part of a cultural and scientific heritage we all share.

Dr Sandra Knapp and Steve Cafferty are at the Department of Botany, The Natural History Museum, Cromwell Road, London