24 ALPINE FLOWERS AND ROCK GARDENS. 



the Arctic Circle to the summit of far-distant mountain 

 ranges, and the great Dutch botanical investigator 

 sees no other explanation than that the species sprang 

 from a common ancestor, existed together in a previous 

 glacial period, and have remained constant and un- 

 changed ever since. 



As an example of the dispersion of Alpine species 

 in Nature, de Vries points out that Primula imperialis, 

 which was introduced from the high mountains of 

 Java, has also been found in the Himalayas, Ceylon 

 and Northern India. Species from Abyssinia have been 

 found on the mountains of the island of Madagascar. 

 Certain familiar Australian types have been discovered 

 in the mountains of Borneo. These species are not 

 to be found in the lowlands (in some cases seas) between, 

 and " the only possible explanation of their identity is 

 the conception of a common post-glacial origin, coupled 

 with complete stability.'* 



The object of de Vries in thus instancing the existence 

 of the same species of Alpines in widely different parts 

 of the world, and their constancy, is, of course, to 

 emphasise the fact that external conditions do not 

 necessarily influence evolution. That is a subject 

 into which it is not our purpose to follow him, but we 

 gladly draw from his rich storehouse of information on 

 plant morphology data of such interest to all lovers of 

 Alpine plants. 



Certain plants are found in both lowland and Alpine 

 regions, and a familiar example is the Harebell, 

 Campanula rotundifolia. In all such cases a difference 

 in the habit of the plants is manifest. Those in the 



