Botanists still prefer paintings to photographs.
Many people regard botanical art as a genre which started at some point in the 15th century, reached its peak with the works of Johann Jakob Walther, Redoute and Ehret, and died at some point early this century - its usefulness eclipsed by the immediacy and accuracy of photography. Not so. Botanical art has not only survived, but is actually thriving, and the genre as a whole is currently enjoying something of a renaissance - as the current exhibition of the Shirley Sherwood Collection at Kew Gardens Gallery in London makes clear.

The plants and flowers represented in the show are analysed petal by petal, stamen by stamen; each minute hair annotated. Colours are built up through washes until the exact pink, red or green is achieved. While the dedication of these artists is all very laudable, and their illustrations remarkable, is their work really necessary? Wouldn't a photograph be a faster, more accurate, and certainly more cost effective means of recording organisms which often die before the artist's paint has dried, and sometimes long before the study is even finished?

The advantage of the artist's eye over the camera becomes obvious the moment you look closely at any of the works in Dr Sherwood's collection. No camera could record the detail required by botanists, and captured by the artists. Thus botanical illustration is an essential means of plant identification, and is regarded as an important scientific tool: "The photograph will give you a very good idea of a plant's habitat," explains Dr Sherwood. "But when it comes to the nitty gritty, a botanist will always consult a drawing." The key to any botanical illustration, she says, is the quality of the specimen recorded, and a good botanical artist will go to any lengths to get that perfect specimen. The lavishly illustrated book which accompanies the exhibition is filled with tales of bulbs that died, plants that wilted or in the case of Paul Jones - who has dedicated his powers of observation and drawing to the camellia - the commission scuppered by a member of the public who unwittingly picked the choice flower and bud he was planning to paint. The commission had to wait a year until the plant was next in bloom.

For many years there has been no real market for contemporary botanical art beyond the academic: at Kew, for example, there are at least a quarter of a million extraordinary studies of the rare and the common-place, all beautifully and faithfully executed (the majority for scientific and horticultural publications), but then consigned to folios where they will be looked at by a couple of hundred pairs of eyes at the most. A meagre reward for such lonely and exacting work.

However the fortunes of the botanical artist have begun to change. The Kew Gardens Gallery shares its treasures with the public, mounting at least two exhibitions a year since its foundation in 1988. While Kew's efforts have met with approval from artists and public alike, Dr Sherwood, botanical artist manque, has been the real force behind moving late 20th century botanical illustration beyond the realms of science and into the art world. Her unrivalled collection, built up over the last six years, has made the works of contemporary artists in this field available to a wider, and hugely receptive lay audience.

Botanical Artists: The Shirley Sherwood Collection is available in paperback from Kew Gardens (pounds 12.99) or in hardback from bookshops (pounds 40). The exhibition at Kew Gardens runs until 2 June.