476 MM. P. Barker- Webb et Sabin Berthelot, 



the flowering plants. Lichens and a few minute mosses mark a farther 

 but now nearly exhausted state of vegetation; and at 11,424 feet 

 Weissia verticillala springs in the crevices, heated by the constantly 

 exhaling vapours. Such is a very rapid sketch of the manner in 

 which the plants rise from the coast to the nearly barren summits. 



In the second chapter, the " Distribution Phytostatique," the 

 distribution of the plants, taken according to the mass of species 

 which prevail in certain ranges, from the shore to the summits of 

 the peaks, with the relation between the vegetation and the cli- 

 mates, have served MM. Webb and Berthelot for the basis of their 

 tables. These differ considerably from those of their predecessors 

 in research : Humboldt selecting Teneriffe as possessing the greatest 

 range of elevation, and placing a height of 10,500 feet as the limit 

 of vegetation, divided their altitude into five zones, viz. the zone of 

 Vines; of Laurels ; of Pines; of the Retamas; and of the Graminece. 

 Our authors, in dissenting from this division, observe, that the first 

 zone is inaccurately defined, for the vineyards occupy but a small 

 space in the whole, and do not reach to the sea, while they cease 

 before attaining the elevation marked for the commencement of the 

 second region. The Quercus Canariensis, (Brouss.) which is noted 

 as indicating the zone of Laurels, is thought to be only the Q. pu- 

 bescens, introduced by the first settlers after the conquest of Tene- 

 riffe, and now in a state modified by climate. The Juuiperus cedro, 

 (Brouss.) which is placed in the third zone among the pines, accord- 

 ing to the researches of our authors, ought to occupy a much higher 

 station. The zones of the Retamas and Graminece, placed at an 

 elevation analogous to the highest ridges of the Pyrenees, should 

 only include the last ; two species of grasses only presenting them- 

 selves on the highest range ; but our naturalists, at the same time, 

 are unwilling to admit any zone of grasses at all, considering that 

 M. Humboldt must have been deceived by false accounts, and stat- 

 ing, that none of the Cerealia are now cultivated beyond a height of 

 4,800. 



The distribution of Von Buch is also differed from ; here the 

 same island is divided into five zones, characterized by elevation and 

 temperature. 



1. La region subtropicale ou des 



formes Africains, . 1.200. cl. Egypt and Barbary. 



2. La region Mediterranienne, ou 



des cultures Europeans, 2.580. cl. France and Cent. Italy. 



3. La region tonjours verte, ou celle 



des forets, . . 4.100. cl. Lyons and Lombardy. 



4. La region du pinar, ou des pins 



des Canaries, . , 5.900. cl. France, Scotland, N. of Germany. 



3 



