392 COMPOSITE. 



Rosacea}. The latter is thicker than the rhizome of arnica, being y% to 

 ^ of an inch in diameter ; it is a true root, furnished on all sides with 

 rootlets, and has an astringent taste. The leaves of Gevum are pinnate 

 and quite unlike those'of arnica. 



FLORES ARNICiE. 



Botanical Origin — See preceding article. 



History — The flowers probably in the first line attracted the atten- 

 tion of popular medicine in Germany, as we pointed out, page 390. 



Description — Arnica montana produces large, handsome, orange- 

 yellow flowers, solitary at the summit of the stem or branches. The 

 involucral scales of the capitulum (20 to 24) are of equal length, but 

 are imbricated, forming a double row. They are very hairy, the shorter 

 hairs being tipped with viscid glands. The receptacle is chafly, ^ of an 

 inch in diameter, with about 20 ligulate florets, and of tubular a much 

 larger number. The ligulate florets, an inch in length, are oblong, 

 toothed at the apex, and traversed by about 10 parallel veins. The 

 achenes are brown and hairy, crowned by pappus consisting of a single 

 row of whitish barbed hairs. 



The receptacle is usually inhabited by a fly, Trypeta arnicivora 

 Low ^ ; the Pharmacopoeia Germania (1872) therefore ordered the florets 

 to be deprived of the involucre and receptacle — " flosculi a peranthodio 

 liberati." From a chemical point of view the usefulness of this direc- 

 tion may be doubted. 



Arnica flowers have a weak, not unpleasant odour ; they were for- 

 merly used in making the tincture, but as the British Pharmacopoeia 

 now directs that preparation to be made with the root, they have almost 

 gone out of use in Great Britain. 



Chemical Composition — The flowers appear to be rather richer 

 in arnicin than the root, and are said to be equal if not superior to it 

 in medicinal powers ; yet the essential oil they contain is not the same. 

 It is obtained in but extremely small amount and has a greenish or 

 blue coloration. Hesse (1864) has proved that the flowers are devoid 

 of a peculiar volatile alkaloid which had been supposed to be present 

 in them. 



RADIX TARAXACI. 



Dandelion Root, Taraxacwm Root ; F. Pissenlit ; G. Lowenzahnwnrzel. 



Botanical Origin — Taraxacijmi officinale Wiggers (T. Dens-leonis 

 Desf , Leontodon Taraxacum ^, a plant of the northern hemisphere, 

 found over the whole of Eurof^ Central and Northern Asia, and North 

 America, extending to the Arctic regions. It varies under a consider- 

 able number of forms, several of which have been regarded as distinct 

 species. In many districts it is a troublesome weed. 



History — Though the common Dandelion is a plant which must 

 have been well known to the ancients, no indubitable reference to it 

 can be traced in the classical authors of Greece and Italy ; it is thought 



^ Figured in Nees von Esenbeck's Plantce medicinales, Dusseldorf, ii. (1833) fol. 39. 



