148 ADAPTATIONS. OFXOLOGICAL CLASSIFICATION 



communities as a whole. 1 But it does not seem possible to use develop^ 

 ment as the fundamental basis of classification of plant-communities : 

 for developmental changes are too dependent upon local conditions ; 

 a formation does not develop merely in a single definite direction, but 

 will modify in one direction at one place and in another at another place, 

 according to the prevailing conditions. 2 



1 As regards Denmark see Warming, 1904, 1906, 1907-9. 



* Concerning the oecological nomenclature and classification see : G. Beck von 

 Mannagetta, 1902 ; Brockmann-Jerosch, 1907 ; Cajander, 1903 ; F. Clements, 

 1002, 1904, 1905 ; Cockayne, loc. cit., 1905 ; Cowles, 1899, 1901 ; Drude, 1896, 1905 ; 

 Flahault, 1900, 1901 ; Ganong, 1902; Grabner, 1905, 18980, 1909; Harshberger, 

 1900, &c.; Kearney, 1900; Kerner, 1891 ; A. Nilsson, 1902; Kirchner und Schroter, 

 1896-1902; Shantz, 1905; R. and W. G. Smith, 1898, 1899, &c. ; Stebler and 

 Volkart, 1904; Woodhead, 1906. 



