450 X. GENERAL REMARKS. 



of species, tending to induce further uncertainty in the 

 figures. 



It is not unlikely that" the number of Scottish species 

 may appear to the botanists of that sub -kingdom as being 

 too much reduced below the number for England. The 

 reputed flora of Scotland (here made only about equal to 

 that for the single English county of York) has been 

 somewhat lowered in a manner which may require expla- 

 nation. Several of the truly native species of England 

 occur in Scotland only as doubted natives ; and some of 

 the denizen species of England are more evidently aliens 

 in Scotland. In reckoning up the provinces and counties 

 for such plants, and in deciding on their boreal limits, 

 the very uncertain line of separation, where the native or 

 denizen becomes an alien species, has been conveniently 

 drawn between England and Scotland ; thus giving a 

 somewhat greater abruptness in severing the floras of the 

 two sub-kingdoms than elsewhere apjjears between minor 

 divisions and sections of the island. In example, Viola 

 odorata and Vinca minor, with various other species, have 

 been reckoned in the summaries for eastern and western 

 England ; not so for Scotland, although often mentioned 

 in Scottish floras as if natives, but too usually on slender 

 grounds and on no reasons. 



It has appeared from the census of species, that so 

 many as 57 (or 55) are yet known only in single counties 

 or vice-counties ; that 77 (or 75) have been clearly ascer- 

 tained in single sub-provinces only; and that 111 species 

 are thus limited to single primary provinces ; also, that 

 various other species are restricted to two or three of 

 such sections of Britain. The question will here ration- 

 ally arise, whether some of these species may not be 

 exclusively western, or exclusively eastern, by the acci- 

 dent of their very restricted areas or localities, and not 



