Fortunate Islands 



Suppose one of these navigator seeds has stranded 

 on the coast of a desert island, then it has still various 

 difficulties to meet with. If it is a mangrove seedling, 

 it will only be able to take root and grow if it has 

 happened on a muddy foreshore. It will perhaps ger- 

 minate, but is sure to die if the coast is sandy or 

 coralline. The usual associates of the mangroves can 

 only establish themselves if there is at least the be- 

 ginning of a mangrove swamp. There are, for instance, 

 none of the mangrove association in Tahiti, because 

 apparently there is no place suitable for them. 



But if the newly arrived navigator plant is an ordinary 

 coral strand plant, it will at once take root and begin to 

 grow vigorously. Sometimes they are destroyed by 

 crabs, which nibble off the young shoots, but this seems 

 not to be a common casualty. 



One can see this happening with such a common 

 navigator as Entada which, once established on the 

 shore of an island, soon spreads itself all along the 

 coast, and may even pass inland and be found straggling 

 over the trees and bushes at a long distance from the 

 shore. 



It has apparently happened that the descendants of 

 some of these navigators have not only taken to aA 

 inland life, but have become so modified and changed 

 as to constitute entirely new and peculiar species only 

 found in one of these island groups. This seems to 

 explain at least the various island species of Vigna, 

 Premna, Canavalia, Erythrina, Sophora, and Ochrosia, 

 for each of these genera has a navigating species. 



But one cannot entirely account for all the plants in 

 South Sea islands by these explanations. Many are 

 neither navigators nor descendants of them, nor are 

 their seeds, so far as we know, carried either by wind 

 or by birds. 



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