INTRODUCTORY EXPLANATIONS. 39 



Inverness. To this space we must likewise add a narrow 

 belt winding avoimd the hills of Wales, and characterised 

 by the vegetation of the present zone, rather than that of 

 the zones above or below this intermediate one. Descend- 

 ing from the super-agi"aiian into the present zone, we find 

 some of its chai-acteristics in the first appearance of Con- 

 volvulus sepium, Bryonia dioica, Tamus commimis, Acer 

 campestre, Rhanmus Frangula, Rhamnus cathaiticus, LTlex 

 nanus, Vibummn Lantana, Euonymus europasus and Cor- 

 nus sanguinea ; all of which also occm- in the lowest zone, 

 though none of them are ascertained to be tridy native in 

 the upper portion of the agi-arian region. Unlike the mid- 

 arctic zone, the present includes few or no species which 

 can be deemed entii'ely restricted to it. In common with 

 the zones above, it possesses TroUius em'opaeus, Geraniiun 

 sylvaticum, Habenaria albida, Rubus saxatilis and some 

 other species, which are very rare, if not wholly wanting, in 

 the zone below. 



The Infer-agrarian zone will embrace all the comitiy 

 southward fiom the Dee and Humber (continued into the 

 river Trent), excepting the moimtainous tracts of Wales 

 and the higher hills and moors in the provinces of the 

 Severn and Peninsula. This zone is more particularly 

 characterised by the increased abundance of the species 

 already mentioned as commencing in the zone above. 

 Among the species absolutely restricted to it, as native 

 plants, the Clematis Vitalba is one of the most conspicuous 

 and ornamental. Rubia peregrina is another characteristic 

 species, prevalent in the southern and western counties ; 

 while the Clematis delights in the calcareous tracts of the 

 southern, eastern, and inland counties. Several species are 

 quite peculiar to this lowest, or most southern, of the six 

 zones ; but for the most part, they are too scarce or local 



