378 X. GENERAL RE]MARKS. 



census summary, on page 271) are counted as many 

 times ; entering into all tlieir floras. Even in the mote 

 numerous sub-provincial districts, a hundred and twenty 

 species are ascertained to belong to all their thirty-eight 

 floras ; scarcely eighty species being restricted to a single 

 subi^rovince, and being so counted only once in those 

 local areas, as they would be in the wider spaces. 



The area of Europe has been estimated at 3,650,000 

 square miles. A full estimate of its flora, in even figures, 

 may give 10,000 species. Dividing one number by the 

 other, we get the result of only a single species to 365 

 miles of surface, or an allowance of so many miles to 

 each species, if all grew separately on their apportioned 

 share of the surface. The area of the British Isles, 

 including Ireland, may be stated in even figures at 

 120,000 square miles. The British and Irish Floras 

 together may be called 1450 species. Again dividing one 

 number by the other here, we find the result of only a 

 single species to 82 or 83 miles of surface. In Britain 

 proper, apart from Ireland, we may divide the 88,000 

 square miles of area by 1425 species ; the result being fil 

 or 62 mUes of surface for each. Proceeding downwards 

 to divisions and subdivisions of the island, we should find 

 a decreasing number of square miles in proportion to 

 species ; until, in counties of intermediate size, the num- 

 bers of miles and species become equalised with eaoli 

 other ; while in still smaller areas the species will exceed 

 one to the single square mile ; at length becoming some 

 scores to the square mile in the barren wastes, or some 

 hundreds in the richer and much varied portions of the 

 surface. 



The subjoined list will show the areas and floras, and 

 the proj)ortions between them, for spaces of various di-, 

 mensions within Britain. Although the list prints into a 



