382 



SUBTERRANEAN ORGANS 



developed from buds after the rhizome has flowered, which may not 

 occur for three or four years. 



The under surface is marked with the small dark circular scars of 

 roots, and on the upper surface traces of the leaves, or at least of 

 the fibro- vascular bundles that passed into them, can be discerned, 

 the drug showing distinct evidence of having been peeled. It is 

 hard, heavy, and compact, and breaks with a short fracture, the 



interior being yellowish and horny. 



The transverse section exhibits a 



large stele containing scattered darker 



bundles and a comparatively narrow 



cortex. 



The drug has an agreeable aromatic 



odour and a slightly bitter taste. 



The student should particularly 



observe 



(a) The contractions of the rhizome, 



(b) The scars of leaves upon the 



upper and of roots on the 

 under surface, 



(c) The characters of the transverse 



section, 



(d) The characteristic odour. 



Constituents. By distillation with 

 steam, orris rhizome yields about O'l 

 or 0'2 per cent, of a yellowish, buttery, 

 aromatic substance, commonly called 

 oil or butter of orris ; this consists 



FIG. 205. Orris rhizome. Rhi- principally (about 85 per cent.) of 



myristic acid together with irone, 

 an oily liquid with a powerful odour 

 of violets. Irone is the only aromatic 

 constituent of the rhizome. The drug 

 also contains a crystalline glucoside, 

 iridin, which must be carefully dis- 

 tinguished from the brown, resinous, 



eclectic remedy of the same name ; the latter is obtained from the 



rhizome of Iris versicolor, Linne. 



Uses. Orris rhizome is used as a perfume, dentifrice, &c., although 

 formerly medicinal qualities were attributed to it. 



Varieties. The chief commercial varieties of orris root are the 

 Florentine, Veronese, and Mogadore. A very inferior quality, of small 

 size, dark colour, and little fragrance, is occasionally imported from 

 Bombay. 



205. Orris rhizome. Rhi- 

 zome of Iris germanica. a, 

 constrictions indicating win- 

 ter growth ; 6, 6, young 

 branches ; c, scar left by 

 previous year's flowering 

 shoot. (Tschirch, after 

 Hartwich.) 



