II THE FLORAS OF THE PACIFIC ISLANDS 15 



outside the zone of influence of the regular currents that would 

 bring the seeds of tropical plants to its shores, Hawaii possesses a 

 strand-flora that is meagre in the extreme. Not only does it lack 

 the mangrove formation so characteristic of Fiji, but it lacks also 

 many of the plants of the beach formation that are found both in 

 Fiji and in Tahiti, plants that give a peculiar beauty to the reef- 

 girt beaches all over the South Pacific. Its poverty is sufficiently 

 indicated in the number of its species, thirty in all, barely more 

 than half of the number found in Tahiti, and not much over a 

 third of those occurring in Fiji. Though coral reefs with their 

 accompanying beaches of calcareous sand are relatively scanty, the 

 characteristic littoral plants have not been numerous enough to 

 hold their own against intruders from the inland flora, and endemic 

 species have taken a permanent place amongst the strand plants. 

 The Hawaiian strand-flora has thus quite a facies of its own, and 

 it will be found discussed in Chapter VIL, whilst a list of the 

 plants is given in Note 28. It will thus not be a matter for surprise 

 that the littoral flora of Hawaii follows the principle of buoyancy 

 only in a modified degree. It is true that about two-thirds of the 

 species of the present beach flora possess seeds or seed-vessels that 

 float for months ; but since there are reasons for believing that 

 several of them are of aboriginal introduction, this proportion is 

 reduced to a third. In the list of the Fijian shore plants given in 

 Note 2, those occurring also in Hawaii are preceded by H. 



When we look to the Hawaiian inland flora for indications 

 respecting the principle of the non-buoyancy of the seeds or seed- 

 vessels of inland plants, we find that so far as it has been there 

 tested this principle receives fresh support from the plants growing 

 on the slopes of the Hawaiian mountains. Although the author 

 was only able to sample the inland flora, we have in the list given 

 in Note 6 all kinds of plants, from the forest-tree to the herb, and 

 most varieties of fruits. Excluding a few introduced plants, there 

 are in this list about fifty species of indigenous plants belonging to 

 about forty genera. Of these plants quite 80 per cent, possess 

 seeds or fruits that sink either at once or in a week or two. Of 

 the " buoyant " residue very few have seeds or fruits that will float 

 for months. These apparent exceptions to the principle are in 

 great part capable of being explained on the grounds referred to 

 in Note 5 in connection with the Fijian inland plants ; and I have 

 alluded to them in Note 7. 



The littoral flora of Fiji is essentially Malayan and Asiatic, and 

 for our purpose is eminently typical. Its plants are found far and 



