SECTION JVIII 



SUBTERRANEAN ORGANS 



(Rhizomes, Corms, Bulbs, and Roots) 



The subterranean organs of perennial plants serve as storage-rooms 

 for the reserve material destined for the subsequent use of the plant. 

 These organs often contain accumulated in them alkaloids, glucosides, 

 and other medicinally valuable constituents, in addition to, such 

 carbohydrates as starch, sugar, inulin, &c. ; hence the utilisation of 

 such subterranean organs for medicinal purposes. They are generally 

 collected in the autumn after the summer foliage has filled them with 

 reserve material and before the development of the stem in the spring 

 has partially exhausted them. Whether, however, they are in all 

 cases richest in active constituents at this particular period has not 

 yet been satisfactorily demonstrated. 



In many herbaceous plants, such as dandelion, pellitory, &c., the 

 aerial stem dies down in the autumn, leaving the lower modified portion 

 attached to the root into which it passes more or less imperceptibly. 

 This lower portion of the stem bears the buds destined to develop into 

 new stems ; being a subterranean stem it is to be regarded as an erect 

 rhizome (often called rootstock), and is collected together with the 

 root. Such drugs as dandelion and pellitory root consist therefore 

 of both root and rhizome. 



In other cases the transition from root to rhizome is more abrupt, 

 as it is in valerian, serpentary, &c., but here also both are collected 

 and dried together. In other cases, again, the rhizomes are separated, 

 as they are in ginger and turmeric, the roots being rejected ; or both 

 roots and rhizome occur simultaneously in the drug, as with liquorice, 

 gelsemium, &c. Comparatively few drugs consist either of root or of 

 rhizome (corm or bulb) alone. This being the case it is evidently 

 impracticable in classifying the drugs satisfactorily to separate roots 

 from rhizomes. 



Rhizomes may be defined as stout or slender, prostrate, oblique, or 

 erect, hypogaeic or epigaeic stems. They may be distinguished from 



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