440 Ever-sporting Varieties 



His principle was the study of partial variabil- 

 ity under the influence of climate and soil. In 

 every experiment he started from a single indi- 

 vidual, divided it into two parts and planted 

 one half on a mountain and the other half on 

 the plain. The garden cultures were made 

 chiefly at Paris and Fontainebleau, the alpine 

 cultures partly in the Alps, partly in the Py- 

 renees. From time to time the halved plants 

 were compared with each other, and the cul- 

 tures lasted, as a rule, during the lifetime of the 

 individual, often covering many years. 



The common European frostweed or Helian- 

 themiim vulgare will serve to illustrate his re- 

 sults. A large plant growing in the Pyrenees in 

 an altitude of 2400 meters was divided. One half 

 was replanted on the same spot, and the other 

 near Cadeac, at the base of the mountain range 

 (740 M.). In order to exclude the effect of a 

 change of soil, a quantity of the earth from the 

 original locality was brought into the garden 

 and the plant put therein. Further control- 

 experiments were made at Paris. As soon as 

 the two halved individuals commenced to grow 

 and produced new shoots, the influence of the 

 different climates made itself felt. On the 

 mountain the underground portions remained 

 strong and dense, the leaves and internodes 

 small and hairy, the flowering stems nearly 



