78 MEDICINAL HERBS AND POISONOUS PLANTS 



a little volatile oil^ gum, a bitter substance called geum- 

 bitter, and small quantities of other substances. The 

 Radix Caryophyllatw of the pharmacists is the dried 

 root and underground stem of this plant. The Avens 

 is also in demand by the herbalists. 



^ Fig. 46.— Tonueutil {PoteiUdla 



a. Calyx seen from below, b, HeaO of aolienes. Tormentilla) 



Water Ayexs {Geiivi rivale).—The aromatic, astrin- 

 gent, and antiseptic root of this herb was used in the 

 Middle Ages in making beer, just as hops are used at 

 the present day. In the United States it is used as a 

 tonic and as a febrifuge. It is distincjnished from the 

 preceding herb by tlie possession of large reddisli-purpl© 

 flowers, and the whole plant is hairy. 



The ToRMEXTiL (PotentiUa Torment Ula) and the 

 CiX(iUEFOlL (PotentiUa rej^taus). — Both of these are 



