196 Mitvos^cdivc Criticism, 



table species are not limited and determined by the subjacent roclcs; butfo 

 this there may be a few exceptions. Thus, it is certain that plants must be 

 affected by rocks which influence the moisture of the soil; and, considering 

 the peculiar and energetic properties of lime, it is not an improbable guess 

 that it may be eventually established that certain plants are confined to the 

 limestone rocks." The question as to the relations subsisting between soils 

 and plants. Dr. Murray acknowledges to be a subject far more difficult than 

 the influence of rocks on plants. He does not discuss this subject ; but he 

 says, " In all probability, the native plants of any given region will, when 

 other circumstances are equal, grow and prosper in any soil, some excep- 

 tions being necessary, chiefly on the score of moistness." 



" The limiting of certain vegetables to certain soils is favoured by no 

 analogy which can be drav/n from animals, who live and prosper in nearly 

 all regions." 



Vegetables in a state of cultivation, and especially those cultivated for 

 particular parts, as the root, fruit, &c., may be favoured by circumstances 

 in the rock and soil, that do not influence native uncultivated species, 

 which alone form the subject of these remarks. From all that we have been 

 able to observe and to read on this subject, we are inclined to conclude 

 that climate has a much greater influence on plants than either rocks or 

 soil. The geological circumstances of the earth's surface cannot be mate- 

 rially different in every zone, and yet the plants are materially so. 



Dr. Murray's article occupies nearly ten pages ; and, although published 

 in June, is dated January 19. 1831. Strictures on J>. Murray's first article, 

 and on Mr. Thomson's remarks on it, as given in our Vol. III. p. 410., occur 

 by Causidicus (Vol. IV. p. 460.), headed " Geological Relations of Plants.'* 

 These strictures we received on January 7. 1831, and regret that we omit- 

 ted the date at the close of the article. As they were written prior to Dr. 

 Mumiy's second article, and we did not publish them till September last, 

 it is probable that they have not yet met Dr. Murray's notice. — Cond. 



Changes in the Habitats of Plants. — Sir, The interesting remarks of your 

 correspondent Mr. Lees (Vol. IV. p. 437.), in which he appears unable 

 to account for the changes in the habitats of plants, have induced me to 

 offer a few observations, which, I trust, will cause somebody of greater 

 experience to take our hopes and fears into consideration, and give an ex- 

 planation satisfactory to us both. It appears, even from Mr. Lees's own 

 showing, that the loss of rare plants from particular places must, in some 

 measure, be attributed to enclosure and cultivation ; but, I fear, the hands 

 of numerous collectors must also be blamed for their entire removal from 

 well-known habitats. On the other hand, Mr. Lees says, " beautiful plants 

 occasionally rise up in stations where they were before unknown." It may 

 be some consolation lo prove that this is also caused by cultivation ; and, 

 therefore, I trust we not only run no risk of losing old favourites, but that, 

 as long as any waste land remains to be ploughed up, we may look forward 

 to new plants discovering themselves. I am led to hope this from the fol- 

 lowing circumstance : — A friend who had been in the habit of peeling turf 

 from a hill for his lav/n and garden, remarked to me that, at whatever time 

 of the year this was done, plants of various kinds sprang up, when it was 

 scarcely possible the seeds could have been sown there after the turf was 

 Cut ; and, consequently, I imagine they must have lain in the soil an 

 unknovv'n time. Perhaps some one of your correspondents better acquainted 

 with the subject, will be able to inform me what time it is probable seeds 

 will remain in the ground without vegetating ; if, as in this instance, they 

 were prevented by a thick coating of grass, with its matted roots, through 

 which, I understood, the plants were not accustomed to force their way. 

 1 am. Sir, yours, &c. — .7. //. H. Oxford, Sept. 1 7. . 1 83 1 . 



Ascent of the Sap. — Sir, In Vol. IV. p. .542. is an ingenious theory of the 

 ascent of sap in trees, by H., as follows : — " The theory I wish to prove 



