358 A NATURALIST IN THE PACIFIC ch. xxvr 



peculiar species. A few species, however, still keep up a connec- 

 tion with neighbouring island-groups. Should this be severed we 

 get the type of genus belonging to the earlier period of the 

 Malayan era as described in the preceding chapter, a genus pos- 

 sessing only peculiar species and destined, after ages of further 

 isolation through the failure of the dispersing agencies, to give rise 

 to a new generic type or types. 



(6) Frugivorous birds were chiefly active in dispersing these 

 genera over the Pacific. Some of the genera possess seeds or 

 " stones " of such a size that at first sight their transport by 

 frugivorous birds to Hawaii seems improbable ; but, as in the case 

 of Elseocarpus, it is shown that this difficulty does not apply to all 

 species of a genus, some of them having much smaller seeds 

 or stones. 



(7) The close of the era of the general dispersal of Malayan 

 plants over the Polynesian Islands is indicated by those genera 

 that are represented more or less entirely by widely ranging 

 species. Though such species may vary among the different 

 groups, they rarely take the rank of polymorphous species, the 

 agencies of dispersal being sufficiently active to check marked 

 variations. 



(8) Several of the genera of this concluding stage, like Rhus, 

 Viscum, and Plectronia, are known to be dispersed by frugivorous 

 birds, whilst others, like Osteomeles and Dianella, are equally well 

 suited for this mode of dispersal. 



(9) Distinct indications are afforded by the genera Rhus, 

 Osteomeles, and Dianella that the Hawaiian Group has been often 

 supplied with its plants directly from the Old World by the 

 Asiatic mainland, whilst the groups of the South Pacific have 

 received different species of the same genus by Malaya and 

 tropical Australia. 



