INTRODUCTORY ESSAY. 3 



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regard to the European genera, which in some parts literally 

 form the mass of the flora, we find them but vaguely indicated 

 in our best authorities; and the European and British spe- 

 cies have, as we have said already, been almost invariably de- 

 scribed as new, without examination or comparison, and many 

 of them more than once or twice. Yet all these elements 

 must be approximately settled before we can attempt a solu- 

 tion of those great questions involved in Botanical Geography, 

 which place it as a philosophical study in the foremost ranks 

 ,of science : we allude to the laws which govern the develop- 

 ment, progression, and distribution of forms and species; the 

 connection of these laws, not only with one another, but with 

 physical features ; and their modifications by geological change. 

 TV e must know at what rate European and African plants dis- 

 appear in advancing eastwards in India, and Malayan ones in 

 following an opposite direction ; how the Chinese, Japanese, 

 and North American genera and species mingle with western 

 forms along the Himalaya and Khasia ; and the exact amount 

 of Arctic and Siberian plants, which are spread all over the 

 loftier Himalayas, and descend the valleys of the Indian wa- 

 tershed. And lastly, there are extraordinary anomalies to 

 unravel, or to secure on a basis of accurate observation ; such 

 as the absence of Oaks in the peninsula of Hindostan and 

 Ceylon, though they abound on the opposite shores of the 

 Bay of Bengal continuously from the Himalaya to Java; the 

 want of any Pine whatever in the peninsula of Hindostan, 

 and of Cycadeq* in Ceylon; and many other points of the 

 highest interest, that have never yet attracted the attention 

 of naturalists, and want illustration previous to explanation. 



We cannot pursue these interesting subjects here, nor dare 

 we, in our present ignorance of botanical facts, allude to the 

 connection which we think shadowed out between the geolo- 

 gical events that have resulted in the present configuration 

 of the Indian continent and peninsulas, and the lines along 



which certain groups and species of plants have consequently 



been distributed. 





