44 A NATURALIST IN THE PACIFIC chap. 



of a mangrove-swamp, and on the banks of an estuary. The 

 climbers, such as Entada scandens, Mucuna gigantea, Derris 

 uh'ginosa, &c., belong more to the mangrove and to the inter- 

 mediate formations than they do to that of the beach. Referring 

 the reader to the more complete lists given in Note 24, I may 

 remark that it is not always possible to distinguish sharply between 

 the three formations, since some of the plants belong to two, and a 

 tree like Cerbera Odollam may, in different localities, be referred to 

 all three formations. The general distinction, however, prevails in 

 the physiognomy of the coast-flora. 



The mangrove-formation comprises, it may be pointed out, 

 many plants other than mangroves, plants that find a home in the 

 mangrove-swamps of Fiji, either within their limits or at their 

 borders. It presents, indeed, a world in itself When the man- 

 groves establish themselves in a new locality they carry along 

 with them a host of hangers-on, both plants and animals, that only 

 find a home under the favourable conditions of a mangrove- 

 swamp. Thus, the absence of the mangrove-formation from a 

 Pacific island deprives its littoral flora of many very striking 

 features. For this reason the Tahitian shore-flora must seem to a 

 botanist coming from Fiji comparatively tame and monotonous ; 

 whilst that of Hawaii, for this and for other reasons to be subse- 

 quently mentioned, is still less interesting, and scarcely even gives 

 a character to the coasts. 



We are now, therefore, prepared to learn that a large number 

 of the plants other than true mangroves, that thrive in or around 

 the Fijian mangrove-swamp, are not to be found in those Poly- 

 nesian islands where true mangroves do not exist ; and that a law 

 of association here exists. Many of the plants of the intermediate 

 formation are so closely bound up with the mangroves in their life- 

 conditions that they are not to be found where the mangroves are 

 absent, even though their seeds or fruits are pre-eminently fitted 

 for dispersal by the currents. The influence of " station " here 

 rules supreme. This matter will be treated more in detail when 

 discussing the Tahitian and Hawaiian strand-floras in Chapters 

 VI. and VII. 



THE MODES OF DISPERSAL OF THE FIJIAN STRAND-PLANTS. 



The predominant influence of the currents having been already 

 established, there remains for consideration the distribution of the 

 floating capacity of the seeds or fruits among the different forma- 



