A STUDY IN PLANT ADAPTATION. 



By Peofessoe J. W. TOUMEY, 



YALE UNIVEESITY. 



"IT^VBEY one interested in plants knows that they are very depend- 

 -^— ^ ent upon their surroundings. The atmosphere and soil con- 

 ditions that suit one species are often totally unsuited to another. In 

 the process of development the different species become structurally 

 and physiologically modified with the change of environment ; they take 

 on certain adaptions, where they succeed best, which particularly fit 

 them to their surroundings. 



Every plant in order to grow must receive material from the outside 

 and must get rid of waste matter. The plant does not differ in any 

 essential respect from the animal in this regard. So also, the plant, in 

 order to continue from generation to generation, must bear offspring and 

 leave them in situations favorable to their growth. 



In all seed-plants the food materials are essentially the same. The 

 ability of a plant, however, to avail itself of these materials depends 

 very largely upon a close correlation between the structure and the 

 physiological activities of the plant organs and its environment. Thus 

 a plant like the apple wiU not succeed in a hot and arid climate, while, 

 on the other hand, the date will not thrive beyond the limits of the 

 desert. 



The sensitiveness of many plants to a slight change in soil or cli- 

 mate and the necessity for a perfect adaptation to a particular environ- 

 ment are illustrated in the very restricted range of many of our native 

 trees and shrubs. 



On the Pacific coast the Monterey cypress is only found growing 

 naturally over a strip of territory, south of the Bay of Monterey, about 



