CHAPTER XXXIV 



GENERAL ARGUMENT AND CONCLUSION 



The problems concerned in the study of the floras of the 

 Pacific islands from the standpoint of dispersal are here ap- 

 proached through the buoyant quality of the seed and fruit ; and 

 it is shown when dividing the plants into two groups, those with 

 buoyant and those with non-buoyant seeds or fruits, that there has 

 been at work through the ages a great sorting process, by which 

 the plants belonging to the group first named have been mostly 

 gathered at the coast. Its operation may be also observed within 

 the limits of a genus, where the species possessing seeds or fruits 

 that float is stationed at the coast, whilst the species with seeds or 

 fruits that sink makes its home inland. 



When the principle here involved is applied to the British flora, 

 it presents itself as part of a much wider principle, by which plants 

 endowed with buoyant seeds and fruits have been stationed at the 

 water-side, whether on a river-bank, or beside a lake or pond, or 

 on a sea-beach. The broader principle proves in its turn to belong 

 to a far larger scheme, in which the fitness or unfitness of a plant 

 to live in a physiologically dry station appears as the primary 

 determining quality, the xerophyte (the plant of the dry station), 

 provided with buoyant seed or fruit, finding its way to the coast, 

 and the hygrophyte (the plant growing under more moist condi- 

 tions), that is similarly endowed, establishing itself by the side of 

 the river, or the lake, or the pond. 



When dealing with the general character and composition of 

 the strand-plants of the tropical Pacific, it is shown that in Fiji the 

 beach-plants often assert their primary xerophilous habit or fitness 

 for occupying any dry station by extending into the inland plains 

 on the dry sides of the islands. The P'ijian shore-plants are 

 divided into three formations, those of the beach, those of the 



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