520 Miscellaneous. 



was ignoraut at the time of its being a new species, and in conse- 

 quence communicated it to Professor Balfour under the name of 

 Conferva Broivnii. 



Dr. Harvey's shght doubt as to the British form of Cladophora 

 repens being the same species with that described by J. Agardh is 

 entirely dispelled by these specimens from Ireland, in which the 

 articulations, although variable, are in general shorter than in the 

 Jersey specimens gathered by ^liss Turner, and intermediate in size 

 between Agardh's plant and that described by Harvey. 



3. " On the British species of Arctium,'^ bv Charles C. Babington, 

 M.A., F.R.S. &c. (See p. 369.) 



4. "Register of the Flowering of certain Plants in the Royal 

 Botanic Garden, from 14th Feb. till 13th March 18.56, as compared 

 with the five previous years," by Mr. M'Nab. 



MISCELLANEOUS. 



On the Influence of the Soil on the Distribution of Plants. By 

 M. Stur. Communicated by Count Marschall. 



In a Memoir presented to the Imperial Academy of Sciences of 

 Vienna, March 6, 1856, M. Stur, treating of the influence of the 

 soil on the distribution of plants, gave the results of the observations 

 made by himself in the Alpine region of Austria. 



The soil on which plants live is either rocky or disintegrated. 

 The " rocky " or solid soil is either of calcareous or of argillaceous 

 and siliceous nature. The " disintegrated" or detrital soil is com- 

 posed of fragments from the "rocky," agglutinated by mineral 

 substances of tertiary origin ; it contains therefore lime, silica, and 

 alumina, in more or less equal portions. 



The rocky soil prevails in the higher elevations of the Alpine region ; 

 the detrital soil fills up the bottoms of the valleys and depressions. 

 The first corresponds to the continents surrounding the tertiary sea, 

 or to the islands emerging from it ; the second indicates the extension 

 of this sea itself, as formed by drift deposited on its bottom. 



The nature of the roots is an essential condition for the thriving of 

 any plant on either of these soils. Species with annual fleshy, or with 

 compound fasciculated, roots, or with underground stems, can only 

 live on detrital soil ; those with woody roots, with numerous rami- 

 fications, are best fitted for the rocky soil. 



A comparison of the flora of the higher calcareous region with the 

 mica-schist flora proves the plants of either of them, although equal 

 in size, to diff'er so materially from each other in shape, that it must 

 be admitted that the geological constitution of the soil has an influ- 

 ence on the vegetation covering its surface. 



Alpine plants carried down by the streams into the plain increase 

 in size and grow more luxuriantly in their new station. Forest-trees 



