^4 A NATURALIST IN THE PACIFIC chap. 



Most of these plants hail from the Indo-Malayan region. 

 Speaking generally of the extension eastward of the Indo- 

 Malayan strand-plants over the Pacific, Prof Schimper (page 195) 

 remarks that they become fewer and fewer in number as they 

 extend farther from their original home, their number shrinking to 

 a very few in the most remote groups of the Marquesas and the 

 Hawaiian Islands. This is well illustrated in the following 

 numerical results that I have prepared. Of the whole number, 

 some seventy in all, of the littoral plants of the tropical Pacific 

 with buoyant seeds or fruits, Fiji possesses about sixty-five, Tahiti 

 about forty, and Hawaii only about sixteen. As shown, however, in 

 Chapter VII., some of the Hawaiian littoral trees that are useful 

 to the aborigines were probably introduced by them. The number 

 actually introduced through the currents into Hawaii in all 

 likelihood therefore does not exceed ten. There is a method in 

 this diminution in numbers, as the plants migrate eastward and 

 northward over the Pacific, which has been described in detail in 

 the preceding chapter. The efficacy of the currents as plant- 

 dispersers in the tropical Pacific therefore diminishes as we proceed 

 eastward. 



In the South Pacific the littoral plants preserve their Old 

 World origin as far as the Polynesian archipelagoes extend east- 

 ward across to Pitcairn, Elizabeth, and Ducie Islands, where we 

 ifind in one or other of them such characteristic Indo-Malayan 

 beach trees as Barringtonia speciosa, Cerbera Odollam, Guettarda 

 -speciosa, Hernandia peltata, and Tournefortia argentea (see Note 34). 

 In the more distant Easter Island there is a suspicion, for the first 

 time, of immigration from South America in the presence of 

 5ophora tetraptera. In the islands relatively close to the 

 American continent, as in Juan Fernandez and in the Galapagos 

 ^roup, the Indo-Malayan strand-plants are no longer represented. 



We come now to consider the relation between the distribution 

 of the shore-plants and the currents. It is quite legitimate to 

 •discuss the currents of the Pacific from the botanist's point of view, 

 that is to say, from the standpoint of the distribution of littoral 

 plants with buoyant seeds or fruits. For ages the buoyant seeds 

 -and fruits of the strand-plants of the tropical Pacific have been 

 drifting over that ocean, and we have the results now before us in 

 the dispersal of the species to which they belong. There is no 

 necessity to endeavour to make the distribution of such littoral 

 plants square with the arrangement of the currents as shown in a 

 •chart. The usual result of such a comparison has been to lead the 



