INTRODUCTORV EXPLANATIONS. 53 



thus disposing of a large portion of these local species, 

 there are still some others left on hand, which cannot be 

 so fairly assigned to any of our six principal types. Po- 

 tentilla rupestris and Anthericum serotinum, for instance, 

 are peculiar to single mountains in North Wales. As lo- 

 cal western species they might be associated with the 

 Atlantic type ; but the hilly and inland nature of their lo- 

 calities, and their absence from the provinces of South 

 Wales and the Peninsula, come inconveniently in conflict 

 with the chief characters of the Atlantic type. Draba ai- 

 zoides and Cotoneaster vulgaris, found on the rocky coasts 

 of Wales very locally, approximate rather nearer to that 

 type, and might be associated under it, in so far as Bri- 

 tain is concerned; and yet, if we should extend our views, 

 so as to take in their distribution upon the continent of 

 Europe, this would be found a misposition. Some other 

 less local species have also a distribution which does not 

 correspond with that of any of the six types specified ; 

 their localities being restricted to calcareous rocks, and 

 occurring in such positions as not to place them properly 

 under one of those types. Examples may be mentioned in 

 Draba muralis and Hutchinsia petraea, the distribution of 

 which is strictly neither eastern nor western, northern nor 

 southern ; and, though they are in some degree hill plants, 

 yet they are certainly not Highland species ; while their 

 very limited area separates them as clearly from the Bri- 

 tish or general type. Eriocaulon septan gulare is another 

 anomaly, which was associated with some very few other 

 species into the ' Hebridean type ' of the former work. 

 But as these few did not make a congruous group, and 

 were numerically too insignificant to be set up against 

 those of the other six types, the Hebridean is here dis- 

 carded, and its half-dozen species divided between the 

 Scottish and Local types. 



