100 A NATURALIST ON DESERT ISLANDS. 



home after having once established themselves on the 

 beach and played their pioneering part. 



It is true that in some instances, in the islands Mr. 

 Guppy wites of, certain species have crept inland along 

 paths which conform to the arid conditions of the beach ; 

 or again certain genera possess both inland and littoral 

 representatives, or the original littoral ancestor may have 

 long since perished in the struggle for existence, leaving 

 its inland descendants with no record wherewith to trace 

 their descent or explain their presence on the island : 

 but in the main, as Mr. Guppy points out, the beach 

 and inland floras have been developed on independent 

 lines, and in only a seventh of the whole beach flora can 

 any question of a connection between coast and inland 

 species of the same genera be raised." 



From all which considerations and without entering into 

 more details, we may, perhaps, take it for granted that the 

 majority of the trees and plants to be met with in the 

 woods of Swan Island have not got there by the aid of 

 floating seeds, in spite of the fact that Swan Island is so 

 narrow that the whole of it might be regarded as littoral. 



The influence of wind, which is such an important agent 

 in the transport of Alpine species to high mountainous 

 islands, and in the conveyance of the spores of ferns 

 and other humble plant colonists, can almost be ignored 

 in the case of our little islands — if we except such plants 

 as the Phyllanthus, the fungi, lichens and grasses, etc. 

 Therefore we are left with the inference that practically 

 the major portion of the flora owes its existence to the 

 unconscious efforts of birds.* 



One could, of course, easily picture the time when, 

 after a period when Swan Island first existed as a flat 

 reef almost awash — ^the home of flamingoes, herons, 

 frigate-birds, gannets, and waders — ^the seeds of littoral 

 plants drifted to it, estabhshed themselves, and formed 



* Even the seeds of the hog plum {spondias) which are capable of 

 floating for an indefinite tinxe, and which are constantly found washed 

 up on the shores of Jamaica, do not, according to Guppy, gain a 

 footing by means of marine currents. 



