and subjacent Rocks. 425 



viously, however, I shall venture a very few remarks on the 

 opinions of others in relation to the same subject. 



The authors of our general floras of Britain have not 

 attempted any thing beyond occasional notices of the soil 

 which some particular species appear to affect. Of our local 

 works, the recent Flora Dcvoniensis and Flora of Berwick on 

 Tweed alone treat of this. . The authors of the former deny, 

 almost in toto, the existence of any decided affinities; while 

 the author of the Berwick Flora points out some few seem- 

 ingly strong examples. The principal papers on this subject 

 are in this Magazine, and they will of course be familiar 

 to its readers. This is now more particularly true, since the 

 substance of Dr. Murray's remarks in the Edinburgh New 

 PhilosophicalJournalhixve, been repeated in this Magazine [in 

 the present volume, p. 335 — 344.]. It is very justly remarked 

 by this writer, that " the distribution of vegetables is mainly 

 regulated by climate; a term implying a combination of cir- 

 cumstances which depend very much upon altitude and lati- 

 tude: " and, if the propositions presently to appear be correct, 

 the influence of rocks over the plants of any two compared 

 districts can only become very evident where all the other 

 circumstances are as nearly as possible at an equilibrium, 

 which rarely occurs. A comparison, therefore, of the floras 

 of Aberdeenshire, Edinburgh, and Devonshire, adopted by 

 Dr. Murray, will not be at all adequate to determine the 

 influence of subjacent rocks, since the more potent sway of 

 climate differs so widely in the latter. Dr. Murray takes a 

 few natural orders, and shows that Devonshire is wanting in 

 a greater number of the Aberdeenshire species than is Edin- 

 burgh : thou eh the latter presents a greater dissimilarity of 



le • tiofjhi 

 county, and which could not be expected to re-appear theri 

 however favourable the rocks might be; while the climate of 

 Edinburgh, and its geographical proximity, are highly fa- 

 vourable to similarity of vegetation. Several of the plants 

 common to Edinburgh and Aberdeenshire, but not found in 

 Devonshire, are those which affect vegetable earth, and ac- 

 cordingly they find a congenial soil in the woods and bogs of 

 the former, uninfluenced by the rocks that lie beneath. Sup- 

 pose we meet this with an opposite example, aim-' 'CoptVaSt 

 the plants of Cambridge with those of other similar and 

 dissimilar districts in regard to ! the^i^rbc^. } in 1 the iPtoja 

 Cantabrigiensis are the following species, considered to have 

 an affinity with calcareous rocks, which they find in the 

 chalk of that county : — )i 



Z/igustrum vulerare, Veronica spicata, Avhna. pubescens, 



