Plants of Europe naturalized in the United States. 155 



Muskingum or Tuscarawas river, but had not crossed to the 

 western bank. In 1831 I met with it, in incredible quantities, 

 every where. The circumstances which prevent some plants, 

 that are naturalized to a great extent in certain localities, from 

 extending generally, are often not to be discovered. Thus, for 

 fifty years at least, Cichoritim intybus is as much spread in the 

 vicinity of Bethlehem as any native plant ; while I never saw 

 it westward of the Susquehannah, nor in this neighbourhood at 

 any considerable distance from the town. The worst enemies 

 of the farmers, at least in the northern states, are all foreigners ; 

 on which account we have reason to congratulate ourselves, 

 that no greater number of these foreign weeds are prone to 

 usurp the soil ; for it is certainly worthy of remark, that among 

 upwards of four thousand species of plants in the United States, 

 not more than from 120 to 130 foreigners should have obtained 

 any thing like a permanent and extensive footing. 



The following few plants, in some degree naturalized in the 

 southern states, are not derived from Europe: — - 



Polycarpum tetraphyllum. 

 Cardiospermum halicacabum. 

 Melia azedarach. 

 Leucas martinicensis. 

 Cucurbita lagenaria. 



