EXPLANATION OF THE MAP. 525 



subdivisions, to be presentlj- subjoined, will render their 

 nomenclature more clear to the eye, and also more satis- 

 factory to the mind of a botanist, by showing its familiarity 

 and uniformity with the ordinary names of the counties 

 and other established sections of Britain, as "Wales, Low- 

 lands, Highlands, &c. 



On the utility of such divisions of a country, definite in 

 boundaries and nomenclature, some mtimation was made 

 on pages 13 and 18 of the first volume. It will become 

 more apparent in my future writings. But I would here 

 particularly request the attention of readers to a remark 

 near the foot of page 18, to the effect that the provincial 

 divisions, like the old divisions into counties, are only ar- 

 bitrary or conventional sections. Indeed, being entirely 

 founded upon the old boundaries of counties, it is obvious 

 that they must be divisions of a corresponding character, 

 though of different dimensions. Strangely enough, Mr. 

 Henfrey has totally overlooked this very obvious corre- 

 spondence ; and notwithstanding my own statement and 

 explanation about these sections being politico-geographi- 

 cal, not natural or botanical, he has informed his readers, 

 in 'The Vegetation of Eui'ope ', page 161, that "Mr. 

 Watson divides Great Britain into eighteen botanical 

 provinces, the boundaries of which are founded upon 

 physical and not political differences ;" &c. True, the 

 grouping of the counties does render the provinces some- 

 what more natural than are the single counties, in respect 

 to their physical geography ; but it does not make them 

 botanical sections at all. The 'Ascending Zones,' il- 

 lusti-ated by a diagram at the left-hand lower corner of 

 the Map of Britain, are true botanical divisions, being 

 founded upon the actual distribution of the plants them- 

 selves, as explained in some detail in the first volume of 

 the Cybele, jjages 19 to 43. 



