200 THE HIGH ALPINE PLANTS 



and structure, which we have seen to be distinctive of 

 Alpine habitats. 



Several botanists in the past have paid special 



attention to this matter. The experimental researches 



of Prof. Bonnier of Paris on the adaptation of plants 



to Alpine climates are of particular importance in 



this connection. We will now glance briefly at his 



methods and results. Prof. Bonnier studied a number 



of species, among others the Harebell {Campanula 



rotundifolia, Linn.), the Kidney Vetch {Aiithyllis 



vulneraria, Linn.), the Bird's-foot Trefoil {Lotus 



corniculatus, Linn.), the Ling {Calluna vulgaris, 



Salisb.) and the Rock Silene {Silene rupestris, Linn.). 



Strong, well-grown examples of these plants from the 



■ Lowlands were divided into two halves, as nearly 



similar as possible. One half of each plant was 



transported to one or other of the experimental gardens 



on the Mont Blanc range, situated at 3,460 feet and 



7,590 feet respectivel}^, or in the Pyrenees to one of 



three small gardens at 2,470 feet, 4,950 feet, and 



7,920 feet respectively. The other half was cultivated 



\at Paris (105 feet above sea-level). The soil used in 



I each case was identical, and everything was precisely 



f similar, except the physical conditions of the chmate 



^of each experimental station, which varied with the 



- altitude above sea-level. 



The experiment was a particularly fair one, for 

 the plant grown as a " control " in the plains at Paris 

 was derived originally from the same individual as 

 the plant in one of the Alpine gardens. In such 



