EXPERDIENTAL CULTIVATIONS 



201 



in 



differing 



experiments "controls," or plants grown under 

 normal conditions, are always used as the basis 

 of comparison with the plants wdiich are being 

 investigated. 



The results of Prof. Bonnier's experiments were 

 remarkable. It will not be necessary to discuss here 

 the different effects pro- 

 duced on each of the 

 very large number of 

 species with which he 

 worked. The con- 

 clusions were similar 



each case, though 

 in detail. In 

 several instances he 

 found that the plants 

 grown in the Alpine 

 regions became dwarf 

 plants, possessing many 

 of the characteristics 

 of Alpine species ; in 

 short, he made Alpine 

 plants. 



The case of the Harebell {Campanula rotundifolia^ 

 Linn.) — of which two examples are seen in Text-fig. 

 XVIIL, taken from Prof. Bonnier's memoir — will 

 afford a good illustration of the effect of the High 

 Alpine climate. The plant on the left is the '' control " 

 grown at Paris. The one on the right is the other 

 part of what was originally the same plant, grown in 



Fig. XVIIL— Plants of the Harebell 



{C(unp(uiula rotundifolia, Linn.). 



That on the left crown in the Lowlands ; 

 that on the riglit in an Alpine garden. 

 (After Bonnier.) 



