202 A NATURALIST IN THE PACIFIC CHAP. 



up chlorides in their tissues, and especially in their leaves, without 

 injury to themselves, is but slightly possessed by such characteristic 

 shore-plants as Canavalia, Pongamia glabra, and Sophora tomen- 

 tosa. This capacity, which, as Professor Schimper indicates, goes 

 to determine whether or not plants are capable of living in salt-rich 

 localities, has often no determining influence with the Leguminosse. 

 (See Note 60.) 



Though the plants of this order form such a large element in the 

 strand-flora of the Pacific islands and of the tropics generally, 

 they seem in other respects, besides those just referred to, to act as 

 if they were strangers to the station. Look, for instance, at the 

 readiness of the floating beans of Mucuna, Strongylodon, &c., to 

 germinate, as shown in Chapter IX, in the tepid waters of the 

 warmer areas of the tropical oceans. This is a great deal more 

 than a disturbing factor of distribution. It is significant also of 

 the plants being out of touch with their dispersing agencies. 



One may notice in conclusion the fact brought out in 

 Chapter VIII that nearly all the littoral plants dispersed by the 

 currents that are common to the Old and the New Worlds belong 

 to the Leguminosae. This is held to indicate that their home is in 

 America, since that continent distributes but does not receive 

 tropical littoral plants dispersed by currents. 



Summary. 



The Leguminosae are far more characteristic of the littoral flora 

 than of the inland flora of the Pacific islands ; and since the greater 

 number of them have buoyant seeds, it follows that this order 

 mainly owes its presence in this region to the currents. 



As it has been shown that in a large number of islands where 

 there is no littoral flora the Leguminosae are wanting, the presumption 

 arises that when, as in Hawaii, inland species occur which at present 

 have no capacity for dispersal by currents, they have been derived 

 from strand-plants originally brought by the currents, even though 

 such shore species no longer belong to the flora. 



As far as its relation to dispersal by currents is concerned, the 

 buoyancy of the seeds of Leguminosae is merely an adventitious 

 character, and the structure connected with it has no specific 

 value. 



Plants of this order in the Pacific are a source of much 

 perplexity and conform to no one rule of dispersal, whether as 

 regards their disconnected distribution, their means of dispersal, the 



