96 A NATURALIST ON DESERT ISLANDS. 



This tree had a habit on Swan Island, very rare among 



tropical trees, of growing in big groups or clumps. There 



were, for instance, one or two places in the woods where 



they grew so thickly together that one might easily have 



thought they had been planted by human agency. Except 



that the bark is of a bright mahogany-broTO, and is very 



smooth (hence the term " Indian skin these groups 



reminded us of plantations of young silver birch, an effect 



enhanced by the number of little wood-warblers which 



used to frequent them, and w^hich seemed, to our fancy 



to take the place of the tits one so often sees among 



birches at home. Possibly these " West Indian birches " 



represented a secondary growth which had sprung up on 



land previously cleared of original wood ; but it would 



be interesting to know the exact causes which had enabled 



them alone to estabhsh themselves over such large areas 



to the exclusion of every other kind of tree. Practically 



nothing grew beneath them but the Pliyllanthus . 

 ***** 



All these plants and trees are examples of true natives, 

 which have found their way at one time or another, in the 

 distant past, to this island by purely natural means. In 

 the remnants of the ancestral woods you may see the final 

 results of an incessant struggle for place, position, and 

 station, amongst a host of such-hke vegetable colonists 

 which have striven to assert themselves, and have either 

 won or lost, or established a compromise — a modus 

 Vivendi — in a racial war. You see, in fact, the well- 

 balanced, more or less stable, result as natural selection 

 and other of Nature's forces have ordered it, up-to-date. 



But the moment you step out of the woods into a 

 clearing, or on to one of the many grassy roads, which have 

 been cut through the woods from one point of the island 

 to another, yoM come upon another class of strugglers 

 and fighters. Many of these are obviously pure inter- 

 lopers, which got an accidental footing on the island through 

 the agency of man. But there are many others — real 

 natives — ^which had simply been biding their time, wait- 



