266 FLORA HISTORICA. 



70VOV5 knee, and it was so called in allusion to the 

 numerous knots in the stalks. The British species 

 of this genus of plants was formerly called Knot- 

 grass on the same account. The name of Persi- 

 caria, by which several of the species are dis- 

 tinguished, is of modern origin, and was given to 

 these plants on account of the foliage of the kind 

 principally used in medicine being similar to that 

 of the Peach-tree, which is called Persica in the 

 Latin language. The leaves of the Oriental Per- 

 sicaria are, however, quite of a different shape, 

 being large, and of a broad oval shape inclined to 

 a point, whilst the Persicaria Urens, Polygonum 

 Hydropiper, has leaves of a narrow oblong shape 

 like those of the Peach. Medical writers dis- 

 tinguish this species by the name of Hydropiper, 

 water and pepper, from its hot, acrid taste, and 

 because it grows in wet situations, and most abun- 

 dantly in places that are under water in the winter. 

 M. Tournefort tells us that the Eastern Persicaria 

 was cultivated in Asia, principally on account of 

 its medicinal properties, which are similar to those 

 of the Hydropiper or Water-pepper, which was 

 formerly held in high reputation in this country on 

 account of its efficacy in medicine ; but its pungency 

 is so great as to be scarcely tolerable, for which 

 reason alone, probably, it is but little used in 

 modern practice. As an external application, in 



