74 FLOWERS 



Arnica flowers have a slight pleasant odour, and bitter, rather acrid 

 taste. 



The student should particularly note 



(a) The narrow, ligulate corollas, with from seven to nine veins 



and three teeth, 

 (6) The straight, bristly fruit and abundant, whitish, bristly 



pappus, 



FIG. 43. Arnica flower. Natural size. 

 (Pharmaceutical Journal. ) 



(c) The linear-lanceolate, hairy, involucral bracts, 



(d) The characteristic twin hairs on the fruit. 



Constituents. Arnica flowers contain traces of volatile oil and a 

 bitter principle, arnicin, which has been obtained in minute, yellow, 

 deliquescent crystals. The flowers are said to contain more arnicin 

 than the rhizome. The drug also contains tannin, resin, yellow colour- 

 ing matter and a phytosterin, arnisterin. 



Uses. Preparations of arnica flowers applied to the skin appear to 

 increase the activity of the circulation, and the tincture, diluted with 

 water, is used for application to the skin ; internally they are stimulant 

 and irritant, but they are now seldom administered. 



