201 



in the pine-woods of Hunlsville, lat. 31" N., long. 95° 30' W. The 

 edible part is the root: immediately below the stem commences the 

 formation of irregularly-shaped potato-like tubers, rather larger than 

 the potato, and so abundant that one plant will yield two bushels. 

 These are used by the Indians made into a sort of bread ; and the 

 pioneer, trapper and backwoodsman are frequently obliged to have 

 recourse to it for the same purpose, and sometimes obtain from it by 

 fermentation a liquor of a pink colour, to which they give the name of 

 beer. Of this plant, and of the mode of growth of its tubers, sketches 

 accompanied the paper, which concludes with a notice of some of the 

 botanists who have visited the State of Texas for the purpose of col- 

 lecting plants, and with a list of the plants collected by Mr. Lindhei- 

 mer in his earlier journey, and by Dr. Kenan. 



Summary of some of the principal Results of the Investigations into 

 the Vegetation of the Alps in connexion icith Height and Tempe- 

 rature. By Dr. Adolph Schlagintweit. 



The author stated that very remarkable differences are to be ob- 

 served in the limits of the altitude of vegetation in the district of the 

 Alps. In the mean results for large divisions, we may plainly recog- 

 nize the influence of geographical position, as well as that of the na- 

 ture of the soil, and of the massiveness of the mountain range. The 

 limit in fact becomes higher the more we approach the southern and 

 western groups, a phenomenon which is connected with the general 

 changes of climate. The mean temperature varies in these latitudes 

 from 0-5° to 07° of Celsius for one degree ; and at the same time the 

 isothermal lines show an evident inclination from west to east. Many 

 very essential differences cannot, however, be explained by geogra- 

 phical position alone ; another important influence is dependent on 

 the form of the mountain-range, the limits of vegetation being gene- 

 rally connected with the mean magnitude of the elevation, and reach- 

 ing higher in massive and lofty groups of Alps than in the lower 

 chains. The favourable influence which the massiveness of the ele- 

 vation exercises on the vegetation, is essentially the same as that 

 which is also evidenced with regard to the temperature of the air and 

 soil ; and corresponds to the difference which is remarked between 

 the climate of a plateau, and that of a ridge or free peak in the neigh- 

 bourhood. In different valleys or on the spurs of a mountain remark- 

 able differences in the altitude of the limit of vegetation often manifest 

 Vol IV. 2 T) 



