XXXI 



limits to the variation in species, which may perhaps be 

 looked upon with dismay by the class of readers for whom 

 this little Work is principally intended. I will therefore 

 now take leave of these topics, and with them of the 

 volume itself, respecting which I will merely remark in 

 conclusion, that without meaning to make myself respon- 

 sible for the accuracy of all the details introduced into 

 its pages, I am ready to bear my humble testimony to the 

 general truthfulness of the descriptions given; and may 

 therefore venture to recommend the Book as one likely 

 to supply a void in the popular scientific literature of the 

 day; inasmuch as the subject is therein handled, on the 

 one hand, in a less perfunctory manner than is commonly 

 done in works embracing the entire extent of Physical 

 Geography, and, on the other, on a less dry and technical 

 plan than appears to have been hitherto the rule in the 

 larger treatises on the Geography of Plants which have 

 come before the public. 



C. D. 



Oxford, November 5, 1855. 



