- ■ HAMILTON SCIENTIFIC ASSOCIATION lOL 



features of distribution, while the great body of facts, anoma- 

 lies and curious details remained unexplained. 



These have now to a large extent been used by such men 

 as Darwin, Benthani, Gray and others who have devoted 

 their lives to this subject to invest the facts of distribution 

 with special importance. The time when a group or a species 

 first appeared, the place of its origin and the area it now oc- 

 cupies upon the earth, become essential portions of the history 

 of the Universe. These men I liave referred to have shown 

 us the marvellous interdependence of every part of nature. 



If there be anything in the theory of life now held by 

 most men of science, and by those who have devoted their 

 lives to the subject of plant distribution, we must come to the 

 conclusion that not only is each organism related to, and 

 effected by, all things livirg and dead that surround it, but 

 every detail of form and structure, of color, food and habits, 

 must have been developed as a result of its organic or inor- 

 ganic surroundings. If that be so, then plant distribution 

 must be as essential a part of the science of life as anatomy 

 or physiology, for it shows as it were, the form and structure 

 of the plant life of the world, considered as one vast organism 

 and it should enable us to understand, however imperfectly, 

 the processes of development and variation, during past ages 

 which have resulted in the actual state of things. It must 

 therefore afford a fair test of the truth of the development 

 theory, or at least, must never contradict it, for the countless 

 facts presented by the distribution of living things in present 

 and past time, must be explainable by some true tlieory. 



But my purpose is not to discuss the theory but rather to 

 present a few interesting facts concerning plant distribution 

 as it has been, and is found to-da5^ 



The first attempt to review the whole subject of Plant 

 Distribution from the modern point of view afforded by 

 evolution is due to Bentham, who was for a long time Presi- 

 dent of the Linnean Society. His conclusions are based upon 

 the experience of a long life devoted to systematic botany. 



The general aspect of vegetation is largely affected by 

 purely physical causes. In the Polar regions for instance, 



