134 A NATURALIST IN THE PACIFIC chap. 



inland species. But the further examination of this interesting- 

 group of genera, which are enumerated in the list below, goes to 

 show that the connection between the inland and coast species of a 

 genus is by no means always so close, or of such a character, as 

 one might have expected. It will not be possible, however, to do 

 much more than indicate in this chapter the results of this 

 inquiry ; but the details will usually be found either in the separate 

 discussion of the genus or in other parts of this work. For 

 convenience of treatment these genera may be grouped in the 

 following sections. 



Grouping of the Plant-Genera of the Islands of the Tropical 

 Pacific that possess both Littoral and Inland Species. 



Section I. Where the littoral and inland species are most 

 probably of independent origin, both possessing their own means 

 of dispersal ; Calophyllum, Hibiscus, Colubrina, Morinda, Scaevola, 

 Cordia, Ipomea, Vitex, Tacca, Casuarina. 



Section II. Where the littoral species have probably given 

 rise to inland species, and both still exist in the group of islands : 

 Vigna, Premna. 



Section III. Where inland species have been probably 

 developed from littoral species no longer existing in the group : 

 Canavalia, Erythrina, Sophora, Ochrosia. 



Section IV. Where the littoral and inland species are 

 evidently of independent origin, and there is no means of 

 accounting for the existence of the inland species by agencies of 

 dispersal at present in operation : Barringtonia, Pandanus. 



Section V. Where in the same genus some inland species are 

 derivatives of the coast species and others are of independent 

 origin : Guettarda. 



Section VI. Where the coast species, having little or no 

 capacity for dispersal by currents, are regarded as derived from 

 the inland species in one group of islands and as afterwards 

 distributed to those in the vicinity : Eugenia, Drymispermum, 

 Acacia. 



Section I 



This group, which includes those genera where the coast and 

 inland species are regarded as of independent origin, both possess- 

 ing their own means of dispersal, contains about half of the total 



