BOTANY 



century is ecology, or the study of the sociology 

 of plants as they jostle each other in their various 

 habitats. This science grew out of plant-geo- 

 graphy, and its general foundations were laid 

 by Drude (1889) and Schimper (1898), who were 

 essentially plant-geographers. In 1895 Warming 

 published an ecological plant-geography in which 

 laws of succession in the vegetation on a given 

 area were recognised, and his (Ecology oj Plants 

 was afterwards published at Oxford in 1909. 



In America the end of the last century was 

 marked by the pioneer studies of Cowles and 

 Clements, the former on the vegetation of the great 

 sand-dunes which border Lake Michigan, and the 

 latter (with Pound) on the vegetation of Nebraska. 



In America, where the vegetation covering 

 great areas, but slightly modified by human inter- 

 ference, can be studied in its broad outlines, the 

 relation of types of vegetation to climate and to 

 succession has been most emphasised. In Britain 

 the British Vegetation Committee, which was 

 formed in 1904, led to a more detailed considera- 

 tion of vegetational types in relation to soils and 

 the various climatic factors such as temperature 

 and rainfall. Its labours resulted in the Types 

 oj British Vegetation, edited by Tansley in 1911, 

 in the International Phytogeographical Excursion 

 through the British Isles in the same year, followed 

 by another through the United States two years 



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