INTRODUCTION TO THE EEPOETS ON INSULAR FLORAS. 5 



are based upon the present relative depths of the intervening seas, and, while admitting, 

 or rather susicjestinsr, a former connection between New Zealand and Eastern Australia, he 

 utterly rejects Captain Hutton's theory of a southern continent uniting the former with 

 South America, and perhaps also with South Africa. Without going so far as Hutton, we 

 think the botanical evidence, as explained further on, strongly favours a former greater 

 land connection in a lower latitude in the south temperate zone than Wallace admits, and 

 we cling to this " forlorn hope of the botanical geographer," as Sir Joseph Hooker terms 

 it ; for all the various means by which plants are diffused seem to be inadequate to 

 account for the present distribution of plants in the coldest southern zone of vegetation. 



Seemann, B. — This author merits special mention here for the immense amount of 

 information concerning the vegetation of Polynesia he embodied in his Flora Vitiensis. 

 How much it contains is only apparent on a thorough examination of the work, for he 

 gives no summary nor tabular view of the distribution of the vegetation. He utilised the 

 collections made by the early voyagers, as well as various unpublished documents relating 

 thereto, in the British Museum. 



Grisebach, A. H. R. — The chapter on Oceanic Islands in Die Vegetation der Erde 

 (and especially as supplemented in the French edition of Tchihatchef) is doubtless the 

 best general account in existence of the botany and geology (the latter only in the French 

 edition) of oceanic islands ; but there are a great many blanks in the floral statistics, a 

 number of which are more or less filled by the present work ; and these insular floras are 

 considered by Grisebach apart from all continental floras. 



Moseley, H. N. — Independently of the collections of dried plants, the drift-seeds and 

 seed-vessels, and the seeds from the crops of pigeons, Mr Moseley has in various publica- 

 tions recorded the observation of a large number of facts bearing on plant geography, 

 which add much to the value of the Reports on the Botany of the Expedition. 



CLASSIFICATION OF ISLANDS IN RELATION TO THE COMPOSITION 



OF THEIR VEGETATION. 



The classification of islands proposed by Wallace, whose definitions are reproduced on 

 the preceding page, harmonises on the whole very well with differences in the characteristic 

 features of the vegetation of some islands ; but it is not adapted for exhibiting the floral 

 peculiarities of islands generally — because, apart from latitude, the sources of the vegeta- 

 tion of oceanic islands, for example, are obviously so various that a classification based on 

 age and the degree of isolation alone is inapplicable. A glance at the composition of the 

 vegetation of the Bermudas and the Galapagos is sufficient to show that these two groups 



(BOT. CHALL. EXP. — INTRODUCTION — 1885.) 2 



