vi AUTHOR'S PREFACE 



The connexion between the forms of plants and the external 

 conditions at different points on the earth's surface forms the 

 subject-matter of oecological plant-geography 1 , which has only 

 recently become a prominent subject of interest, although it found 

 a place in earlier works, especially in Grisebach's valuable ' Vegeta- 

 tion der Erde,' where, however, it was regarded from obsolete points 

 of view. The greater prominence of physiology in geographical 

 botany dates from the time when physiologists, who formerly 

 worked in European laboratories only, began to study the vegeta- 

 tion of foreign countries in its native land. Europe, with its tem- 

 perate climate and its vegetation greatly modified by cultivation, 

 is less calculated to stimulate such observations ; in moist tropical 

 forests, in the Sahara, and in the tundras, the close connexion 

 between the character of the vegetation and the conditions of 

 extreme climates is revealed by the most evident adaptations. 



The physiological branch of geographical botany has made 

 very rapid progress, owing to the foundation of a botanical 

 laboratory at Buitenzorg, and to the unusually favourable oppor- 

 tunity for a residence in the midst of tropical vegetation which 

 is thus offered to botanists in Java, thanks to Treub's praise- 

 worthy exertions. It has thus become possible, as Wiesner's and 

 Haberlandt's pioneering works show, to carry on prolonged and 

 exact physiological research in a tropical climate. It is to be 

 hoped that a counterpart to Buitenzorg may soon be established 

 in the arctic zone ; for an arctic laboratory, with a modest equip- 

 ment corresponding to the poverty of the flora and the relative 

 simplicity of the problems to be solved, would be of great service. 



The oecology of plant-distribution will succeed in opening 

 out new paths on condition only that it leans closely on experi- 

 mental physiology, for it presupposes an accurate knowledge of 

 the conditions of the life of plants which experiment alone can 

 bestow. Thus only will it be possible to sever the study of 

 adaptations from dilettantism which revels in them, and to free 

 it from anthropomorphic trifling, which has threatened to bring it 

 into complete discredit. In this respect, we may congratulate 

 ourselves that scientific botanists are turning more and more to 



1 Following Hackel's initiative the most recent name for the science of biological 

 adaptations is Oecology. 



