THE DISTRIBUTION OF PLANTS. 53 



work on the distribution of species within Britain, than 

 will be found in the hands of any other person, and will 

 consequently enable me to speak with considerable con- 

 fidence regarding such. 



For information on the influence of elevation, and the 

 range and distribution of plants in connection therewith, 

 I have hitherto been compelled to rely almost solely on 

 my own limited and transitory opportunities for observ- 

 ation. This is much to be regretted, so little being pub- 

 lished on the subject, that almost every thing had to be 

 done ; a task beyond the power of one whose place of 

 residence has always been remote from the mountain 

 tracts. And much as my works will show me indebted 

 to botanical friends for their exertions and assistance 

 in other respects, it seems that few of them have felt suf- 

 ficient interest in that department to which I have at- 

 tached the most importance. It is true, and it would be 

 injustice to conceal, that several correspondents have 

 given various useful facts in regard thereto. Thus, in 

 the lists of plants for the Tees, Mr. Hogg has dis- 

 tinguished those chiefly, or only, found in the middle and 

 higher parts of the course of that river. And Mr. Gor- 

 don, also, in the list of Moray plants, has distinguished 

 them into three stages, according to their ranges from the 

 mountains towards the coast. But such divisions, having 

 reference only to their lower limits, can apply to a very 

 small number. Their higher limits, or lines of cessation 

 towards and on the mountains, constitute the most essen- 

 tial inquiry. Very few species reach the mountain- 

 summits, but most of them descend to the shores. I have 

 also derived additional information from Mr. Gordon and 

 Mr. W. C. Trevelyan with respect to the range of several 

 species into the Upland Zone (of the Outlines) which I 

 had not enjoyed the opportunity of ascertaining. In 

 Murray's Encyclopaedia of Geography is a notice of the 

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