N0RXHUMBT5ELAND AND DURHAM. 



307 



agency than to be genuine aborigines, but it is of course impos- 

 sible to draw the Kne between the two classes with any precision. 

 In this eighty -nine we include sixty-three well-established weeds 

 of cultivated ground, and twenty-six which are either trees or 

 plants likely to have been introduced through garden cultivation. 



3. — Classing the plants of the two counties according to the 

 types of distribution of the Cylele Brifannica, we obtain the fol- 

 lowing result : — 



Whole of Britain. 



Northumberland 

 and Durham. 



British type 



■ English ,, 



Germanic ,, 

 [ Atlantic , , 



Highland ,, 



Scottish ,, 



! Intermediate ,. 



Local 



Total 



532 



409 



127 



70 



120 



81 



37 



49 



632 



251 



26 



5 



36 



57 



21 



7 



1425 



935 



4. — If we arrange the plants of Britain on the basis of this last 

 table in three principal geographical classes, according as they 

 are distributed over its whole extent, or shew a northern or 

 southern tendency, we shall of course find the characteristic pe- 

 culiarities of the botany of the different parts of the island as 

 compared with one another, in the absence or presence of the 

 plants of the two last classes. The characteristic of the North of 

 England is that it yields a fair proportion of both of them. In 

 Northumberland and Durham we have one hundred and fourteen 

 out of the two hundred and thirty-eight northern and montane 

 plants, and two hundred and eighty- two out of the six hundred 

 and six comparatively southern species. Of the eighteen bota- 

 nical provinces defijied in the Cyhele the richest in number of 

 species are those of the south-east of England. The Thames 

 province, which includes Kent, Surrey, Berks, Oxford, Bucks, 

 Middlesex, Herts, and Essex, an area of 7000 square miles, yields 

 one thousand and fifty-one species. The Channel province, which 



