THE PLANTING OF OUR FLORA 151 



Stream, thus putting them aboard the great trans- 

 port which carried them to their final destinations. 



On the floor of any tropical forest there are 

 always decaying limbs and tree trunks, and often 

 in considerable numbers. The exposed surfaces 

 of such fallen timber usually decay first and on 

 them soon forms a thin bed of loose soil. Seeds 

 fall on this and find it an excellent place to germi- 

 nate. On one of these decaying logs in my little 

 hammock I once counted no less than ninety 

 seedlings of trees and shrubs which grew near 

 by, seven species in all. These little plants 

 came from several different crops of fruit, some of 

 them being three or four years old. Digging into 

 the decaying wood I found many other fresh and 

 sprouting seeds. Here was a garden richly planted 

 and all needed to establish it elsewhere would be 

 transportation of the log itself. 



Suppose that such a tree lay in a stream valley, 

 say in North Cuba, and that in time of some great 

 downpour of rain (during a hurricane for example) 

 it was washed into the Florida Strait. The cur- 

 rent of the Gulf Stream moves eastward and north 

 at the rate of about three miles an hour and this 

 would rapidly bear driftwood toward Florida, 



