The Vegetative Key to the British Flora. J. Poland and E. Clement. 2009. Published by John Poland, Southhampton, in association with the Botanical Society of the British Isles, Botany Department, The Natural History Museum, Cromwell Road, London. 526 pages. 24 color plates. $40.00 (£25.00), Softcover. ISBN 13: 978-0-9560144-0-5.
Becoming an expert on identifying naturalized plants in an area is a task that may literally require years of training or practice. Flowers are the key for taxonomic guides, and it may take several seasons before the flowers of a certain plant can be observed in bloom. The British, however, are lucky. John Poland and Eric Clement have provided an excellent tool for identifying British flora not by flowers, but by vegetative characters— characters that are present the majority of the growing season.
This reference is purported to be the most comprehensive vegetative tool for British flora, and it covers nearly 3000 taxa of Great Britain and Ireland. By using a polychromatic key, the manual is well organized and easy to navigate. Plants are divided initially into Divisions based on basic vegetative characteristics (e.g., A, B, … U). Each Division is further divided into Groups based on more specific vegetative characteristics (e.g., AA, AB, … UC), and these groups are broken out into species. Most Groups are contained on one or two pages; so, if selections are made correctly, using the key usually requires no more than three turns of a page.
In the case of a few genera or morphologically similar species that key out in more than one group or division, the key will reference the user to the back of the book where these genera are organized into separate keys, labeled with the first few letters of each group name (e.g., RAN keys out all the species in Ranunculus). However, some group abbreviations are not based on scientific names (e.g., DOCK is used for Polygonaceae). Although this organization might confuse someone who goes instantly to one of these groups of similar species, it has little effect on the usefulness of the guide when directed to the group by an earlier part of the key.
Due to the nature of vegetative characters, some of the useful differences between species are very minute, and identification hardly can be done in the field. Although most plants do not require such detailed study, line drawings of stem and leaf cross-sections are provided for difficult species. For the large genus Carex, color photographs of leaf cross-sections are included. In these cases, of course, the book is less useful as a field guide, but by and large, the usefulness and size of this book would make it a very handy backpack book for field botany.
Overall, this key seems to work incredibly well. In the midwestern United States, the reviewers were able to put this book into action, identifying a fine array of spontaneously occurring European plants (that is, weeds of European origin), and also found it to be a useful guide to the correct genus of most non-European plants. The British are fortunate to have such a quality guide of this type, designed specifically for their flora. The rest of the world can only hope that botanists in their region will take notice and aspire to create similar guides.
