147 



intentional or unintentional introduction, with approximate 

 dates. Some detailed notes on its distribution and habitat in the 

 Old World, and on the other species which is said to grow in 

 Japan, would also be valuable. If our plant grows in India it 

 may also in Africa, and the ancestors of our negroes may have 

 become acquainted with it there. 



Most introduced and cultivated plants prefer comparatively 

 dry soils, that have been or could be tilled; but there are a few 

 other plants indigenous to Europe whose American habitat is 

 similar to that of A corus, and which may have had a similar 

 history. The well-known mints, Mentha piperita and M. spicata, 

 grow spontaneously in marshy places in all or nearly all the 

 eastern states, but are said to have been introduced from 

 Europe. Like the calamus, they are cultivated in some places 

 for their aromatic properties. 



The water-cress, called at various times Nasturtium offici- 

 nale, Roripa Nasturtium, and Sisymbrium Nasturtium-aquati- 

 cum, appears perfectly at home in many of our limestone springs 

 and the streams issuing from them, but is said to be of Old 

 World origin. Like the mints, it is a commercial crop in some 

 places. 



Of similar habitat to the Acorus, but with more restricted 

 range, and no known economic properties, is Lythrum Salicaria, 

 a showy plant of wet meadows in some of the northeastern 

 states and Canada, appearing like a native, but believed to have 

 been naturalized from Europe. 

 University, Ala. 



