Remarks on the Flora of Ceylon. 225 



that the opposite sides of a single mountain exhibit at the same time 

 these opposite states of climate. 



The great variety of surface and of climate, then, which the Island 

 possesses, are favourable not only to a varied, but to a luxuriant 

 vegetation, especially in its central and southern districts. From 

 the study of plants taken in connexion with these circumstances, and 

 their various other physical conditions, has originated the science of 

 Botanical Geography, one of the most interesting branches of Botany, 

 and one which some day will, no doubt, throw much light on the laws 

 which have regulated the production and dispersion of species. It is 

 only of late years that attention has been given to this subject, for, 

 till the natural productions of different parts of the surface of the 

 globe came to be investigated with the attention and accuracy which 

 are peculiar to the present age, naturalists rested satisfied with the 

 vague idea, that all animals and vegetables had originally radiated 

 from a common centre, and that in the same parallels of latitude the 

 same species would be found. This we now know not to be the case, 

 and it can be as safely asserted that every large tract of country has 

 had its own peculiar creation of both plants and animals, as that two 

 and two make four, the exceptions to this general rule being accounted 

 for by disseminating causes now in operation. In no other way can 

 we account for Europe having a totally different class of plants from 

 that part of North America which lies immediately opposite to it ; or 

 for the botany of Southern Africa having little or no resemblance to 

 that of the same parallels in South America, or to that of Australia 

 or for many small Islands, such as that of St. Helena, possessing 

 a vegetation totally different even from that of the nearest continent. 

 Islands, however, in general approach nearest in the nature of 

 their productions to that of the countries to which they most nearly 

 range in a geographical point of view, and this we shall find to be 

 the case with Ceylon. 



Both the climate and the soil of the maritime parts of the west- 

 ern side of Ceylon being very similar to that of the Malabar coast, 

 we find that a large proportion of the plants of both places are 

 identical ; and the same holds good with reference to the northern 

 and north-east coasts of Ceylon, and that of the opposite Coromandel 

 coast, although each district in both countries is found to possess 

 species which are peculiar to each. A vegetation more or less 



2 G 



