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Page:Popular Science Monthly Volume 61.djvu/489

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THE

POPULAR SCIENCE

MONTHLY

 

OCTOBER. 1902.




A STUDY IN PLANT ADAPTATION.
By Professor J. W. TOUMEY,

YALE UNIVERSITY.

EVERY one interested in plants knows that they are very dependent upon their surroundings. The atmosphere and soil conditions 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 will 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 climate and the necessity for a perfect adaptation to a particular environment 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