IV 



TROPICAL FLORAS 49 



the Indian and Pacific Oceans. These conditions have led 

 to its being almost wholly forest-clad, and to its possessing 

 a flora comparable in luxuriance and beauty with that of 

 the great Amazonian plain, situated almost exactly at its 

 antipodes. 



The western half of this archipelago has undoubtedly 

 been united with the continent at a comparatively recent 

 geological epoch, and this portion of it, both in its animal 

 and vegetable life, is nearly related to that of the Malay 

 Peninsula and Siam ; but the three chief islands, Sumatra, 

 Borneo, and Java, are of such great extent, and have such 

 differences, both of geological structure and of climate, as 

 to give to each of them a distinct individuality, combined 

 with, in all probability, a wealth of species fully equal to 

 that of the adjacent continent. 1 The remainder of the archi- 

 pelago has had, however, a different origin, and has been 

 much longer isolated. Celebes and the Philippines have 

 certain features in common, indicating a remote but partial 

 union with, or approximation to, the Asiatic continent, and 

 probably subsequent submergence to an extent that has 

 greatly impoverished their mammalian fauna. New Guinea, 

 however, stands alone, not only as the largest island in the 

 world (excluding Australia), but as, in some respects, the 

 most remarkable, both by its extraordinary length of about 

 1500 miles, and its possession of a range of snow-capped 

 :and glaciated mountains. Biologically it is unique, by 

 having produced the wonderful paradise- birds numbering 

 about 50 species ; while its true land -birds already known 

 amount to about 800 species, a number very far beyond 

 that of any other island — Borneo, with its almost continental 

 fauna, having about 450, and the great island-continent of 

 Australia about 500. 



But, as regards plant-life, this vast archipelago is much 

 less known than that of inter-tropical Asia, though it will, 

 I believe, ultimately prove to be even richer. Of the two 



1 The Director of Kew Gardens informs me that, in 1859, the flora of the 

 " Netherlands India," extending from Sumatra to New Guinea, but excluding 

 the Philippines, was estimated by the Dutch botanists to possess 91 18 species of 

 flowering plants then known. As such large portions of all the islands are almost 

 unknown botanically, it seems not improbable that the actual numbers may be 

 three times as many. 



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