IN ASCENDING REGIONS. 



57 



and Azalea; nor is the distance always the same. The 

 selected species are those which usually cease nearly in 

 the order represented, and which from their frequency or 

 visible size form convenient tests or features of the 

 several regions. 



Ascending zones or regions should be marked by the 

 appearance, or lower limits, as well as by the upper 

 limits of species ; but the former are yet more capricious 

 (if such an expression can apply to natural peculiarities) 

 than the latter ; nor can I give an exact scale of them to 

 correspond with the preceding. The region of the plains 

 commences on the south coast of England. Empetrum 

 nigrum and Rubus saxatilis do not extend to the south 

 coast Vaccinium Vitis-Idaea and Arbutus Uva-Ursi 

 scarcely belong to the plains. Saxifraga stellaris and 

 Alchemilla alpina decidedly mark the upland region. 

 Above these appear Thalictrum alpinum, Draba incana, 

 Saxifraga oppositifolia. Silene acaulis and Epilobium 

 alpinum (excluding E. alsinifoliurn) begin in the median 

 region. Cerastium alpinum., Salix herbacea, Azalea pro- 

 cumbens belong to the subalpine region. Luzula arcuata 

 and Saxifraga rivularis are seen only on the Alps. 



In the Outlines, which preceded the present work, a 

 slightly different arrangement was adopted, and it may be 

 useful to compare them together to avoid mistakes through 

 similarity of name not indicating precisely the same thing 

 here. 



Present Regions. 



Outlines. 



Zones. 



Regions. 



Plains - - 

 Uplands - 

 Medians - 

 Subalps 



Alps - - 



Agricultural - 1 

 Upland - - J 

 Moorland - 1 

 Subalpine J 

 f Alpine - \ 

 \ Snowy - J 



Wooded. 



Barren. 



Mossy. 



D 5 



