III. TYPES OF DISTRIBUTION. 31 
fairly assigned to any of the six principal groups. Potentilla 
rupestris and Lloydia serotina are peculiar to single mountains in 
North Wales, and are found considerably below the highest 
summits. As local western species they might seem properly to 
associate with those of the Atlantic type, did not the hilly and 
inland character of their special localities, and their absence from 
the provinces of South Wales and the Peninsula, come incon- 
veniently in conflict with the chief characters of the Atlantic type. 
Draba aizoides and Cotoneaster vulyaris, found very locally on the 
rocky coasts of Wales, approximate rather nearer to that type, and 
might be associated under it in so far as Britain alone is con- 
cerned ; 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 well with that of any of the 
six types specified ; their localities being restricted to calcareous 
rocks, and being such as net to place them properly under one of 
those types. Examples may be cited in Draba muralis and 
Hutchinsia petrea, the distribution of which is strictly neither 
eastern nor western, northern nor southern; and though they are 
in some degree hill plants, they are unknown in the Scottish 
Highlands; while their very limited area separates them as 
clearly from the British or general type. Eriocaulun septangulare 
is another anomaly, limited to Ireland and a few islets on the 
western side of North Britain; the species beimg otherwise 
American, not European. 
This mode of viewing the distribution of plants is still 
essentially a climatic classification of them, though not exclusively 
so. It would seem not incorrect to regard the types as repre- 
senting so many present climatic areas, which are not separated 
by limitary lines, as the climatic zones are supposed or feigned to 
be, but which amalgamate or at least intermingle one with 
another. The actual areas and sites of the various species, as 
well as their directions of increase or decrease in abundance, 
appear on the whole to accord so closely with existing climatic and 
other physical conditions, as legitimately to warrant a conclusion, 
