Volume 9 Number 6 



The Plant World 



JUNE, 1906 



THE DISIXTEGRATIXG INFLUENCES OF TROPICAL 



PLANTS. 



By Mel. T. Cook, Ph.D.. 

 Agricultural Station. Santiago dc las J'cgas, Cuba. 



The literature upon the methods of plant distribution and the 

 influences of plants upon their surrounding-s is voluminous, and 

 yet much more might well be written on this very interesting 

 and important subject. Wherever the conditions will permit, 

 plants are continually migrating" into new territory, and thev are 

 also continually making' their old homes unfit for themselves but 

 suitable for other species. In this work, in connection with 

 frost, and water, and animals, thev become one of the greatest 

 leveling forces of nature. They stop the flow and change the 

 courses of rivers : they fill the lakes, converting them into marshes 

 and then into dry land ; they incroach upon the ocean coast line 

 and gradually push it out farther and farther ; they help to level 

 the hills and to tear down the mountains. Neither are the\- 

 respecters of the works of man, for the}" attack and destrov his 

 greatest and noblest structures. His largest castles, temples, and 

 monuments become vine clad, old, ancient, and then historical 

 men"iories, in rapid succession. 



In no part of the western hemisphere is this better illustrated 

 than in the old Spanish fortifications in and around Havana. 

 Here, far south of the frost line, plants become the n"iost im- 

 portant factor in this slow but sure work of destruction ; and, 

 unconfused with other disintegrating" factors, their work is all 



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