INSULAR FLORAS. 



PART V. 



TH E botanical exploration of the African islands of the 

 Indian Ocean has now reached a point that further 

 discoveries will hardly lead to further problematical ques- 

 tions in relation to the geographical distribution of plants. 

 Numerous species still lie undescribed in herbaria, and 

 doubtless many have not yet been collected, and probably 

 new generic types may yet be discovered ; but were every 

 genus and species known we should be in no better position 

 than we are at present for discussing the composition and 

 origin of the flora of these interesting islands. 



I will take Madagascar first, because so much has been 

 written on the relationship of its fauna and Mora ; and, I 

 may add, because the peculiarities of its flora, at least, 

 have been exaggerated and the affinities misunderstood. 

 Following- up Mr. J. G. Baker's investigations, to which I 

 shall have occasion to refer again, I, some years ago, 

 attempted to demonstrate (i) that the flora was essentially 

 African in character, and the enormous accumulation of 

 data since then fully confirm the views there set forth. 



I was impelled to an examination of the facts in con- 

 sequence of the importance attached by Dr. Wallace (2) 

 to the apparent Asiatic affinities of the flora and its dis- 

 similarity from the African flora of the same latitude. 

 This view is even emphasized in his later work (3), from 

 which I quote the following sentence : — ■ 



" As examples of extreme diversity, notwithstanding 

 geographical proximity, we may adduce Madagascar and 

 Africa, whose animal and vegetable productions are far 

 less alike than are those of Great Britain and Japan at the 

 remotest extremities of the great northern continent ; while 

 an equal, or perhaps even a still greater, diversity exists 

 between Australia and New Zealand ". 



Now, I believe that it will be generally admitted that 



