ORIGINAL COMMUNICATIONS. 



XIV. — On the Periodic Phenomena of Vegetable Life at 

 Different Altitudes in the Alps. Translated from the 

 German of Adolplie Schlagintweit.* 



1. Mode of Observation. — An enquiry into the periodic phe- 

 nomena of vegetable life is the more interesting in the Alps 

 from the great differences observable within very short distances. 

 A careful observation of these phenomena often points out changes 

 in climate, which it would be difficult to ascertain by meteorological 

 observations alone. Thus, for instance, the several causes which 

 occasion a variation in the limits of vegetation in respect of 

 altitude become much more apparent. It not unfrequently 

 bappens, that it is only in certain seasons that a combination of 

 circumstances occurs unfavourable to the growth of a given plant ; 

 the disturbances thus produced in the periods of development of 

 such a plant will call our attention to the causes of its lower limit 

 in altitude. 



The great disturbances which the diversity of seasons in dif- 

 ferent years occasions in the development of vegetation make it 

 often difficult to obtain positive results, easily comparable with 

 eacb other. In many special cases, on points either very low or 

 on the summits of the Alps, I have been able to make use of 

 observations already published and extending over a long term of 

 years ; I have also procured detailed notes on many points for 

 the years 1848 and 1849. They are in general taken at the 

 same places for which I have already communicated meteorological 

 observations for the same years. 



It was a great object to me to extend these stations to the limits 

 of growth of Cerealia. Yet it is difficult to obtain authentic 

 observations of this nature for any lengthened period of time, or 

 for any considerable number of points in the Alps, because they 

 depend entirely on the individual care and attention bestowed by 

 the observer. 



* This constitutes the 19th chapter of the Researches on the Physical 

 Geography of the Alps, by Hermann and Adolphe Schlagintweit, Leipzig, 

 1850. 



