THE CONTINENTAL ELORA OE SOUTH SWEDEN 223 



Hence in the first place the object of this study of the continental features in 

 the South Swedish flora has been to determine in detail the distribution of con- 

 tinental species in South Sweden and to explain the position of the limits as far 

 as that is at present possible. 



However, it should even here be pointed out that space does not permit me 

 to treat the problems in as great detail as might have been desirable. 



The study also purposes to give a contribution to the fixing of the ]iosition of 

 the South Swedish flora in relation to that of the rest of Middle Europe. A pretty 

 large space has therefore been allotted to a survey of the continental element in 

 the Middle European flora; and the distribution and mode of occurrence of spe- 

 cies in South Sweden have as far as possible been connected with the distribution 

 and mode of occurrence in the rest of Middle Europe. I have considered it 

 necessary to give this part of the study comparatively considerable space, as by 

 far too little attention would seem to have been paid hitherto to non-Scandinavian 

 relations in our floristic and phytogeographical investigations. 



Some ten years ago, when I began my botanical studies at the University of 

 Upsala, I had the great privilege of taking part in the work of the Plant Biology 

 Seminar and of joining the flock of pupils that Professor RUTGER vSernander 

 had gathered around him. This aroused my interest in the problems of phyto- 

 geography; and it is thanks to the excellent, suggestive and inspiring instruction 

 which I thus received that I am now in a position to put forward some results 

 of my own researches in phytogeography. 



It is thus an agreeable duty to acknowledge in this place my great debt of 

 gratitude to Professor Sernander. 



I have very much pleasure in taking this opportunity of expressing my respect- 

 ful thanks to my teacher in other branches of botany. Professor O. JUEL for the 

 instruction I have received from him and for the kindness and interest he has shown in 

 the pursuit of my botanical work. — I am also deeply indebted to Professor NiLS 

 Syedelius for botanical instruction and for the interest he has shown in my studies. 



To several of my fellow -workers I am deeply indebted for much invaluable help 

 in the working out of this study. In the first place I should like to mention Docent 

 GUNNAR Samuelsson, who, himself occupied with investigations in the sphere 

 of taxonomic phytogeography, has given me a great deal of valuable advice and 

 information. 



To a large extent my work has consisted in the collection of information as 

 to the distribution of certain species. In order to pursue these investigations a 

 very considerable amount of material was necessary. It would have been impossible 

 for me to procure sufficient material within a reasonable time if I had not received 



