Welsh Journals

BOOK REVIEWS Atlas of the British Flora. Edited by F. H. PERRING and S. M. WALTERS. Botanical Society of the British Isles and Thomas Nelson & Sons, Ltd. xxiv + 432 pages, 1962. £ 5 5s. As a standard work on the plant life of our islands this fine book surely ranks with Clapham, Tutin & Warburg's, Tansley's, and Godwin's works. It is the result of the scheme, launched in 1954 by the Botanical Society of the British Isles with the financial support of the Nuffield Foundation and the Nature Conservancy, to map the distribution of the British flora in relation to the 10 X 10 km. squares of the Ordnance Survey National Grid. Over five or six years some 1,500 volunteers, ranging from schoolchildren to the most eminent of botanists, recorded in the field on specially printed cards all the species of flowering plants and pteridophytes that they could find in each of these grid squares. There are about 3,500 such squares in the British Isles and only 7 were not worked-a fine achievement considering the remote districts of Ireland, the inaccessible Scottish islands, as well as the industrial wastes of lowland England, that had to be covered. The mass of data in herbaria and the literature was also worked. About 1 million records were accumulated, and it was possible to process them and produce maps only with the aid of modern mechanical equipment. The Atlas contains about 1,600 of these maps, four to a page, showing the distribution in the British Isles of all but the critical species of vascular plants, and each record is represented by a spot or similar symbol on the appropriate map. (Critical species, and subspecies and hybrids, are to be dealt with in a companion volume now being prepared.) The fineness of the 10 X 10 km. grid square as a recording unit, compared with the old vice- county', can be appreciated from the fact that there are about 23 times as many grid squares as vice-counties in these islands. Thus by the old system the whole of Merioneth would be blacked out on a map for Neottia nidus-avis because of a single plant that was once found near Dolgellau by the new system only one spot is shown out of a possible 30 for the vice-county, which is a typical Welsh one in size. The book also has a 15-page Introduction, a list of unconfirmed vice-county records, and-particularly useful-transparent overlay maps showing January and July mean and February minimum temperatures, rainfall, humidity, and the distribution of high ground and limestone. The first edition of a book based on an entirely new principle is bound to have faults. Most of the moderately uncommon species are clearly under-recorded one wishes that provisional maps could have been circulated for improvement before publication, but presumably the cost would have been too great. But it is a tribute