For some years there has been general agreement about the need for an international registration system for names of dahlia cultivars, because of the large number of new cultivars produced each year and the confusion which has arisen when two distinct cultivars are given the same name, or when one cultivar is given different names by growers in different countries. Discussions about the appointment of an International Registration Authority for Dahlia Names took place at the 16th International Horticultural Congress in Brussels in 1962 and subsequently at the Congress in Maryland in 1966, when The Royal Horticultural Society was appointed I.R.A.
The Society had for many years maintained an index of dahlia names amounting to several thousand but the first task of the l.R.A.was to secure international agreement to a classification system. The Society is most grateful for the cooperation in preparing and agreeing the classification, which appears on page vi, given by those interested in Dahlias throughout the world and in particular for the help provided by the National Dahlia Society in this country and the respective Societies in Holland and the U.S.A. The classification finally agreed is based on ten Groups: some difficulty was found in agreeing a further sub-division of some of these Groups according to size, as this factor depends on such considerations as cultivation, climate and soil. Such a subdivision was thought to be desirable, however, more particularly for show purposes and it was finally decided to include these subdivisions (also set out on page vi), it being understood that the category indicated is that of the cultivar in its country of origin, from information received from that country. National Societies, when preparing show schedules, should bear this point in mind and make any adjustments necessary.
Having obtained general acceptance of the classification for international use as opposed to national show purposes, the I.R.A. asked national organisations to supply lists of dahlias in cultivation and such lists were submitted by organisations in Belgium, Denmark, France, Holland, Israel, the U.S.A., Western Australia and West Germany. The I.R.A. is indebted to those who compiled these national lists.
The names thus obtained have been correlated with the records already held by this Society and names have also been obtained from current catalogues. This Tentative Classified List and International Register of Dahlia Names is the result. Though it is not claimed that errors have been entirely eliminated, it was considered essential to issue a list as quickly as possible so as to help prevent any further duplication in the use of names. The I.R.A.will be grateful to all who take the trouble to give information about omissions or errors of any kind which may then be corrected before the
next edition is printed.