85 



enquiries from trustworthy seed merchants and agricultural associations. 

 Several countries already possess such statistics, and as such information 

 is very valuable in many ways, it is much to be regretted that replies 

 were received from several quarters to the effect that it was impossible to 

 collect reliable data in this connection. Generally speaking, however, 

 we may say that the proposals adopted by the Congress at Copenhagen 

 have been favourably received. 



To my regret, soon after the conclusion of the Congress, I was 

 prevented by other urgent work from devoting myself fully to the further- 

 ance of these investigations, and thus the material which is presented 

 to-day is chiefly the result of the laboiir of the following gentlemen : — 



1. Dir. K. Dorph-Petersen, Copenhagen, for Denmark. 



2. Dir. A. W. Franck, Wageningen, for Holland. 



3. Dir. Jon Enescu, Bucarest, for Roumania. 



4. Gustav Wiksell, Stockholm, for Stockhohns-Lan. 



My special thanks are due to these four gentlemen for putting at 

 my disposal the results of their researches for use in the preparation of 

 my report presented to-day. 



I am glad to say that in several other countries similar investigations 

 have been initiated, so that in time further information on this subject 

 may be expected. 



Thus I received only some days ago interesting res\ilts of fxurther 

 examinations by Mr. Edgar Brown of Washington (red clover of the 

 United States), Dr. F. Wahlen of Ottawa (red clover of the province 

 of Ontario) and a very valuable paper on the distribution of some weeds 

 which are " determining " for red clover of Southern France by Dr. Louis 

 Frangois, presented by Prof. Bussard. I am sorry it is not possible to 

 make use of these papers in my lecture. 



In condensing the results it was found desirable to distinguish the 

 nature of the occurrence of seeds of other species both in regard to their 

 frequency and number. It is a different thing, whether a species occurs 

 constantly, taut only in small numbers, in all samples, or only in few 

 samples in very great numbers, i.e., in dominating numbers. In this 

 respect and in accordance with the terms used in botanical geography, 

 the frequency might be called constancy, and the mmibers in which the 

 species occurs dominancy. As regards the frequency, it was considered 

 suitable to differentiate between : — 



very frequent, i.e., those occurring in 75 • 1 — -100 per cent, 

 frequent „ „ 50- 1 — 75 per cent, 



less frequent „ „ 25 • 1 — 60 per cent, 



unimportant „ ,. 0*1 — 25 per cent. 



In the condensed statements that follow, the frequency (constancy) 

 s expressed by stating the nmnber of samples in which each species 

 was found. In addition, the four above-mentioned sub -categories are 

 given separately. The nimiber (dominancy) is expressed by the as- 

 certained highest number in 1,000 gr. and by the average number of samples 

 in which the species was found at all. Perhaps it would have been more 

 correct to calculate the average and the standard deviation, as in this 

 way it could also be ascertained whether a difference in the number of a 

 species from two separate sources, arrived at by investigation, may be 

 considered as reliable. As, however, it raay be confidently asserted 

 that the result would not have justified the great amount of necessary 

 calculations, we abstained from this method of deduction. It will 

 always be possible, later on, to determine the rehabiUty of a difference 

 by referring to the original tables. 



I have condensed the results of the investigations by the four gentlemen 

 mentione'd above into short summaries, which are added as appendices 

 to my report. In discussing the results of these siommaries, I would 

 point out that their bearing on the practice of investigations into country 

 of origin must be kept separate from the deductions to be drawn as to the 



