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XLV. Memoir respecting the State cf Vegetation on high 

 Mountains, Readin the National Institute, June 1804. 



J. hr* first thing which strikes an observer of plants at the 

 entrance of high mount a'ns in our temperate regions, is the 

 vigour and luxuriance of vegetation : every thing he has seen 

 in the adjacent plains suddenly changes its dimensions, its 

 aspect, and its form; he scarcely knows the most common 

 plants under the new dress which they have assumed. The 

 stems are high, the flowers enlarged ; and even the leaves 

 of trees have acquired such an amplitude, as often excites 

 some doubt in regard to the identity of their species. The 

 groves are better clothed with foliage, the grass thicker as 

 well as more abundant, its green colour livelier; in a word, 

 every thing is enlivened with more brilliancy, from the 

 depths of the valleys to those heights where the eye can 

 discern nothing but bare rocks and eternal snow. 



The plants being thus endowed with a vigour of vegeta- 

 tion unknown in other places, they tend with more energy 

 to pass through the periods of their existence. Time, which 

 regulates the periods of it, creeps on with a slow pace in 

 our plains, but in the mountains it flies. Every thing 

 hurries on along with it: meteors succeed each other with 

 extreme rapidity; the air there is in continual agitation; all 

 the determining causes act at once with their whole force; 

 the signal of germination, floration, and fructification is 

 given at the same time to all individuals placed under the 

 same conditions. The decoration of the meadows and fo- 

 res! s changes suddenly at the pleasure of the south wind, 

 of a storm, or stroke of the sun, which uniformly affects the 

 whole of certain kinds of species ; and each day of the fine 

 season is the spring of an order of vegetables, or of one of 

 the regions in which they grow. 



This first view is succeeded by another; in traversing the 

 mountains and valleys, each situation has its own soil, and 

 each region .its climate. These particular regions have each 

 their productions : each has its own characteristic vege- 

 tables, which are distinguished in the number of those cos- 

 mopolite plants, whose temperature, more robust or more 

 •e, seems to adapt themselves to every soil, and to tri- 

 umph over every climate. In the plains these local distinc- 

 tions occupy immense spaces, the limits of which are too 

 extensive and too indeterminate to be easily perceptible. 

 In the mountains every thing, on the other hand, is con-» 

 filled within narrow limits, which the eye often embraces 



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