xvni THE LEGUMINOS^ OF THE PACIFIC ISLANDS 203 



structural cause of buoyancy, the loss of buoyancy of inland species, 

 and in other particulars. Even in their physiological constitution 

 they are often at variance with the bulk of littoral plants when they 

 grow on the sea-shore, since typical beach-plants of the order, 

 though thriving in salt-rich localities, are shy of salt in their 

 tissues. 



It is probable that whilst the Pacific islands have derived most 

 of their littoral plants that are dispersed by currents from the 

 tropics of the Old World, they have received most of their strand 

 Leguminosse from America. 



