58 EXPLANATIONS OF THE FORMULA. 



presently to be explained. The numbers which are en- 

 closed by curves, thus ( ), will indicate the provinces 

 within which the species can scarcely yet be deemed really 

 wild, although existent there. Those nvmabers which are 

 enclosed by angles, thus [ ], will refer to the provinces 

 within which the species has been reported to occm-, al- 

 though under circumstances of doubt which render some 

 confirmation necessary ; most of the provinces so distin- 

 guished being probably eiToneous. 



The second and third hnes give the north and south 

 limits of the species in Britain, by naming those counties 

 in which occur their extreme localities- The selection of 

 counties to be cited, is made with reference both to the east 

 and the west sides of the island ; whereby to convey some 

 idea of the relation of the species to longitude also. Thus, 

 for instance, the county of Glamorgan is named in the north 

 limit of the Clematis ; although the other two covmties, 

 Salop and Norfolk, are much more northerly. This is 

 done, because, so far as yet ascertained, the coimty of Gla- 

 morgan is the north limit of the Clematis in the longitude 

 of Wales ; the alpine character of the two Welch provinces 

 being unfavourable to a shrub which requires a wai-m sum- 

 mer. Our lists of Cornish plants being yet very incom- 

 plete, Devon will be named as the south limit of many 

 species which doubtless do grow also in Cornwall. 



The foui-th line is devoted to a sort of censu.s of the spe- 

 cies. This can only be given approximately, by estimat- 

 ing the number of provinces and of counties within which 

 the species is deemed hkely to occm\ It is probable that 

 the number of provinces will be set down coiTectly for the 

 majority of the species ; though there may still remain a 

 considerable minority, for which the number of provinces 

 will ultimately be found less exact. The lists of species 

 for South Wales, the Lake Province, and the North and 



