xv LITTORAL AND INLAND PLANTS' RELATIONSHIP 151 



This would just come within the limitations laid down by Gatke 

 as regards length and velocity of flight — a subject discussed in 

 Chapter XXXIII. 



We will now turn to the Sophora seeds themselves for evidence 

 of their capacity of surviving the perils of such a journey. The 

 seeds of Sophora chrysophylla, which are about a quarter of an 

 inch (6 to 7 mm.) in length, possess unusually hard coverings for 

 the order, and in that respect appear fitted for dispersal by animals. 

 Indeed, in the large island of Hawaii wild pigs and sheep feed on 

 the pods, and no doubt aid in the distribution of the plant over the 

 island through the germination of ejected undigested seeds. But 

 since the species is found on most of the larger islands, it is 

 apparent that to birds we must look for the explanation of its 

 inter-island dispersal. Mr. Wilson, in his Aves Hawaienses, 

 remarks that one of the Hawaiian finches (Loxioides) feeds on the 

 seeds of this tree, which probably, he adds, also serve as the food of 

 Chloridops kona, another big finch ; and it is to be inferred from 

 the observations of Mr. Perkins, quoted by Mr. Evans in his book 

 on Birds, that the Drepanididae, a family peculiar to Hawaii, are 

 in the habit of splitting the pods of trees like Acacia koa and 

 Sophora chrysophylla to obtain the seeds. It would, however, 

 seem that the agency of birds confined to these islands does not 

 carry us very far when we wish to explain the original transport of 

 the seeds over a breadth of ocean of some 1,500 miles and more. 

 Yet we know that this must have happened with some of the 

 Hawaiian plants, such as Osteomeles anthyllidifolia and Nertera 

 depressa, that are not confined to these islands and possess fruits 

 that would attract frugivorous birds. But whether it has occurred 

 with the dry beans of the Hawaiian species of Sophora is another 

 matter. 



On the whole I am inclined to the view, bearing in mind the 

 general indications of the Leguminosae in the Pacific, that S. 

 chrysophylla originally reached Hawaii as a littoral plant through 

 the agency of the currents. Many points still need investigation ; 

 but it may be pointed out that South America probably received 

 Sophora tetraptera from New Zealand by the West Wind Drift 

 Current. 



OCHROSIA (Apocyneae). 



This genus seems to offer the strongest testimony in support of 

 the derivation of an inland species from a strand-plant. The 

 drupes are so large, the minimum size of the "stone" being ii or 



